Feasibility Study for Solar Cooling Systems

ALTENER Project Number 4.1030/Z/02-121/2002

GUIDELINES FOR SOLAR COOLING FEASIBILITY STUDIES

&

ANALYSIS OF THE FEASIBILITY STUDIES

ALTENER PROJECT

CLIMASOL

May 2005

Guidelines for solar cooling feasibility studies page 2

LIST OF CONTENTS

A. Guidelines for solar cooling feasibility studies 0/ INTRODUCTION.................................................................................................................4

1/ DATA OF THE PROJECT...................................................................................................7

1.1/ General presentation 1.2 / Cooling equipments 1.3/ Orientation of the study 1.4/ Pre-sizing using SACE Solar cooling Light Computer Tool 2/ SYSTEM SIZING...............................................................................................................13

2.1/ Sizing data 2.2/ Chiller

2.3/ Solar collectors 2.4/ Cooling tower (only for closed cycle technologies) 3/ THERMAL BALANCE OF THE SOLAR SYSTEM.......................................................15 3.1/ Calculation method

3.2/ Meteorological data 3.3/ Data on "domestic hot water consumption" 3.4/ Component features

3.5/ Presentation of the calculation results 4/ INSTALLATION & WORKING PRINCIPLES.................................................................17

4.1/ Installation principle 4.2/ Working principle

5/ SYSTEM TELEMONITORING..........................................................................................19

5.1/ Functions of the telemonitor 5.2/ Description of the measurments 5.3/ Monitoring 6/ ECONOMICAL BALANCE................................................................................................20

6.1/ Evaluation of the cost of the project 6.2/ Evaluation of the annual savings 7/ ENVIRONMENTAL ADVANTAGES...............................................................................23


B. Analysis of the CLIMASOL feasibility studies 1/ INTRODUCTION...............................................................................................................24 2/ MAIN DESCRIPTION OF THE STUDIES........................................................................24 3/ STATISTICAL ANALYSIS OF THE STUDIES................................................................25

3.1/ Technical parameters 3.2/ Economical parameters 3.3/ Environmental benefit 4/ CONCLUSION AND FUTURE OF THE STUDIED PROJECTS....................................34 ANNEX : DETAILED PRESENTATION OF 5-6 REPRESENTING CASE STUDIES.......34

A) DEC system (9,5 kW) : Conference room (Marathon, Greece) B) Absorption system (8,6 kW) : Office building (St Etienne, France) C) Absorption system (200 kW) : Office building (München, Germany) D) Adsorption system (10 kW): Office building (Milano, Italy) E) Absorption system (15 kW) : Metal Industry (Schlierbach, Austria) F) Absorption system (35 kW) : Laboratory (Grenoble, France)


A. Guidelines for solar cooling feasibility studies 0/ INTRODUCTION

Indoor comfort depends on many factors. Most dominating out of them are indoor temperature and humidity. The indoor temperature felt by an individual of course depends on both air temperature and the temperature of surrounding wall surfaces. Indoor temperature and humidity depend on many factors which are related to the climate of the site, the building and its construction and user depending factors. Most important climatic factors are the solar radiation, outdoor air temperature and outdoor air humidity. Building related factors are among many others the buildings thermal mass, building orientation, window sizes and characteristics, shading devices and their control, construction of walls and ceilings etc.. Internal loads strongly depend on internal equipment and use of artificial lighting, infiltration and ventilation gains and occupation of rooms by persons.

Goal of the presented guideline for solar cooling feasibility studies is to show how to realize a feasibility study using a solar cooling system. The different chapters briefly give general notions to build a structured feasibility study.

Details about the used technologies and the different system configurations can be found in the Handbook “Solar-Assisted Air-Conditioning in Buildings – A Handbook for Planners” which has been produced in the framework of Task 25 [Hans-Martin Henning (Editor); Solar-Assisted Air-Conditioning in Buildings – A Handbook for Planners. Springer Wien/NewYork; ISBN 3-211-00647-8].

For more information on the results of the Climasol project, a brochure has been produced in English and in the different national languages of the participating countries.

A website is dedicated as well to the project at www.raee.org/climasol.

In introduction, the following decision scheme is to guide the decision for a certain technical solution for a given situation, defined by climatic, building and occupation related factors as described above. Finally each solution represents a technical solution to use solar thermal energy for building air-conditioning.

A basic scheme to guide the decision is shown in Figure 1Figure 1. A basic assumption is that both, temperature and humidity of indoor are to be controlled. The starting point always is a calculation of cooling loads based on the design case. Depending on the cooling loads and also according to the desire of the users/owner, either a pure air system, a pure water system or hybrid air/water systems are possible for extraction of heat and humidity out of the building. The basic technical decision is whether or not the hygienic air change is sufficient to cover also cooling loads (sensible + latent). This will typically be the case in rooms/buildings with a requirement of high ventilation rates, such as e.g. lecture rooms. However, a supply/return air system makes only sense in a rather tight building, since otherwise the leakages through the building shell is to high. In cases of supply/return air systems both thermally driven technologies are applicable, i.e., desiccant systems as well as thermally driven chillers. In all other cases only thermally driven chillers can be used in order to employ solar thermal energy as driving energy source.


Cooling load calculation (buildingparameters, e.g., materials,

geometry, orientation; internalloads, meterological conditions)

⇒ cooling load, requiredhygienic air change

Hygienic air change able to covercooling load?

Pure air system:Full air system

(supply and exhaust air)

yes

yes

yes

no

no

no

Installation of centralized airhandling unit feasible and

desired?

Pure chilled water system

Distribution mediumTechnology

Building

Supply air system+ chilled water system

no

Conv. AHU, thermally driven chiller,

chilled water network6°C - 9°C (Figure 7)

Climate

temperateand extreme

yesFull air system

(supply and exhaust air)+ chilled water system

Climate

temperate extreme

Thermally driven chiller,chilled water network6°C - 9°C (Figure 6)

Climate

temperateand extreme

Building constructionappropriate for supply /

return air system (buildingtight enough)?

Building constructionappropriate for supply /

return air system (buildingtight enough)?

DEC system, standardconfiguration,


Conv. AHU, thermallydriven chiller,


DEC system, specialconfiguration,


Climate

temperate extreme

DEC system,standard configuration

(Figure 2)

Conv. AHU,thermally driven

chiller6°C - 9°C

DEC system, specialconfiguration

(Figures 3 and 4)

yes

Figure 1 – Basic scheme for decision guidance

The lowest required temperature level of chilled water is determined by the question whether air dehumidification is realized by conventional technique, i.e., cooling the air below the dew point or whether air dehumidification is realized by a desiccant process. In the latter case the temperature of chilled water - if needed at all - can be higher since it has to cover only sensible loads. Application of desiccant technique in extreme climates, i.e., climatic conditions with high humidity values of the ambient air, special configurations of the desiccant cycle are necessary in order to be able to employ this technology. More items of the design which cannot be covered in this presentation are for instance:

- Necessity of a backup system for the cold production or to allow solar autonomous operation of the solar assisted air conditioning system;

- Flexibility in comfort conditions, e.g. to allow certain deviations from the desired air states;

- Economical issues;

- Availability of water for humidification of supply air or for cooling towers;

- Comfort habits for room installations: fan coils have lowest investment cost, but allow dehumidification only when connected to a drainage system; chilled ceilings and other gravity cooling systems require for high investment cost, but provide high comfort.

It is not indicated here, which type of thermally driven chiller is applied. In case of a desiccant system is required with an additionally chiller to cover peak-loads, the required chiller may be an electric driven compression chiller for economical reasons.


A basic technical scheme of a system which contains both open desiccant cycles and closed cycle water chillers is shown in Figure 2Figure 2. Also different options of back-up are shown in Figure 2Figure 2, namely back-up on the heat side by other heat sources (e.g. gas burner, connection to a district heating network, co-generation plant etc.) and a back-up compression chiller. To provide cooling in the room several solutions are possible: a fan-coil system which is used in summer and winter, a radiative cooling system such as chilled ceilings or a ventilation system providing fresh air which is cooled and dehumified.

storage heat cold production

sola

r co

llect

or

air handling unit ho

t w

ater

cold distr. building, loadheat prod. storage cold

chill

ed w

ater

con

dit

ion

ed a

ir

oth

er h

eat

sou

rces

heat distr.

Figure 2 – Scheme of a complete system including desiccant technique and heat driven water chiller


1/ DATA OF THE PROJECT 1.1/ General presentation

Description of the type of building (place, area, use) Building in construction, renovation program

1.2 / Cooling equipments

• Load calculation & thermal balance

• Planned HVAC system (central ventilation, decentralized ventilation, other cooling equipment beside air treatment, ....).

• Place of the technical premices

• Reasons of the choice of a solar system (power limitation, environmental

considerations)

1.3/ Orientation of the study

List of criteria permitting to evaluate the level of suitability of a solar cooling system with the load :

- power range of the load if less than 8,6 kWcold :

è no absorption chillers available è desiccant cooling system available requirinq centralised air

distribution system if more than 35 kWcold :

è power range of the absorption chillers : multiple number of 35 kWcold

è power range of the adsorption chillers : multiple number of 70 kWcold

è desiccant cooling systems : no power range restriction - seasonal correlation of the load with the climate

The amount of solar cooling energy usable will be directly depending on the correspondance between the season (more or less sunny) and the load (occupation level, load profile) - daily adequation between solar energy available and load profile The best situation is a diurnal load profile with peak load at midday. The use of a storage capacity will be required whether the peak load is in the morning or in the evening.

- available space for the solar cooling components


It is very important to see where a solar collector field can be installed and integrated in the architecture of the place. Same question for the technical premices (not forget the cooling tower in a ab/adsorption chiller configuration) After considering these different criteria, it is relevant to choose a strategy for the solar cooling system in the entire cooling system :

- pre-cooling of the chilled water loop in summer and pre-heating in winter if

use of an absorption system - other strategy permitting to increase the solar fraction : study of the ratios

solar cooling and net collector efficiency (cf. next chapter) 1.4/ Pre-sizing using SACE Solar cooling Light Computer Tool

The SACE Solar Cooling Light Computer Tool is a fast and easy-to-handle computer tool to study the feasibility of using solar thermal energy for building air conditioning. It has been developed in the framework of the EU project SACE Solar Air Conditioning in Europe by Fraunhofer Institute for Solar Energy Systems ISE.

1.4.1. General scheme of use

The tool has the function to carry out a draft feasibility study about application of solar cooling for a given load file and a given solar collector. The tool uses a combined meteo-load-file as input (produced with TRNSYS or any other similar program) and a configuration file for definition of the system. The format of the meteo-load file has to follow exactly the following scheme: hour Oper Vdot Troom rhroom Tamb rhamb Pheat Pcool Phumi Pdehu Itot Idif Icol theta - - m3/h øC % øC % Wh Wh Wh Wh Wh/m2 Wh/m2 Wh/m2 ø 1 0 0.0 19.60 51.0 8.30 70.0 0 0 0 -0 0.0 0.0 0.0 0.0 2 0 0.0 19.60 51.0 8.30 70.0 0 0 0 -0 0.0 0.0 0.0 0.0 3 0 0.0 19.40 50.0 7.80 72.0 0 0 0 -0 0.0 0.0 0.0 0.0 4 0 0.0 19.30 48.0 7.60 73.0 0 0 0 -0 0.0 0.0 0.0 0.0 . . in total 8760 lines, one for each hour of the year . . 8757 0 0.0 19.50 56.0 12.30 76.0 0 0 0 0 0.0 0.0 0.0 0.0 8758 0 0.0 19.30 56.0 11.70 79.0 0 0 0 0 0.0 0.0 0.0 0.0 8759 0 0.0 19.20 55.0 11.50 80.0 0 0 0 0 0.0 0.0 0.0 0.0 8760 0 0.0 19.10 55.0 11.20 82.0 0 0 0 0 0.0 0.0 0.0 0.0

Figure 3 – Scheme of the format of the meteo-load file

1.4.2. Basic description of the method

Based on meteo-load-file and configuration of the system the annual solar fraction for heating and cooling is calculated based on an hour-by-hour comparison of needed heat for a thermal driven cooling and available solar heat. A parametric study for different collector areas, expressed as specific collector area AA (m2 of collector per m² of conditioned room), is automatically carried out. In order to assess the effect of storage, also different sizes of a heat storage, expressed in kWh of storage capacity per m2 of collector, are considered. Purpose of this


method is to achieve a first assessment of a reasonable value of collector area and storage size for a given meteo-load system and a given solar collector.

1.4.3. How to install and use the tool

Steps for installation are : 1. Copy the ZIP-File SACE-SolCool-Tool.ZIP on your computer 2. Extract the ZIP-File; the File-structure should be the same as in the ZIP-File Steps for use are :

1. Open SACE Solar Cooling Light Computer tool by Double-Click on ‘SolarCoolingLight.exe’ in the main directory.

2. Open ExCel and open the Work Sheet ‘Postprocessor_SolarCoolingLight.xls’ in the path ..\ResultFiles

3. If you want to open a saved configuration file from the hard disk: Chose a configuration file either by clicking on the ‘File’ in the top line or click on the Open File button. Select a file from the file list.

4. The window on the left hand side of the screen shows all parameters which have to be defined in order to run asimulation. You can either use the values from the current configuration or change them. To save the configuration file with a new name click on ‘File’, ‘Save Config File’ in the main menu and chose a name for the new file.

5. Insert all the parameters for the chosen system (solar collector, room, global efficiencies of backup heater and thermal driven chiller). It is important that the value of the room area is identical with the area of the rooms which were used for the production of the load file. If you use for instance an example file for the hotel, you should also use the area of the hotel example, which is contained in the respective configuration file.

Figure 4 – Example of the interface of the SACE Tool


Chose a meteo-load-file either by clicking on the ‘File’ in the top line or double-click on ‘Load and Meteo Data File’ or click on the Open File button. Select a file from the file list. In this list you can add own files produced with any building simulation program with the file format as described in chapter 2.

6. Start Simulation by clicking on ‘Calculate’ in the top line and then choose to start calculation either with or without saving the configuration file.

7. Go to ExCel in the Work Sheet ‘Postprocessor_SolarCoolingLight.xls’

8. Press ‘Ctrl j’. An Excel Macro should start which inserts values from the latest simulation into the Excel work sheet in the tables ‘Input’ and ‘Time_series’.

9. To save results save the ExCel-File under a new name.

10. The following pages show examples of the results and describe the meaning.

1.4.4. Results

Figure 5 – ExCel-Table ‘Calculation’ in the work sheet ‘Postprocessor_SolarCoolingLight.xls’: Solar fractions for heating, cooling and

Specific collector

area

Heat storage

size

Heat for Cooling

Heat for Heating

Radiation on

collector

Gross collector output

Backup Cooling

Backup Heating

Solar Fraction Cooling

Solar Fraction Heating

Solar Fraction

Total

Gross collector efficiency

Net collector efficiency

m2/m2 kWh/m2

collkWh/m2

roomkWh/m2

roomkWh/m2

coll.kWh/m2

coll.kWh/m2

roomkWh/m2

room% % % % %

0.1 0 128.17 67.75 1566.42 840.39 100.34 55.58 21.71 17.96 20.42 53.65 25.540.2 0 128.17 67.75 1566.42 840.39 82.21 51.04 35.86 24.66 31.99 53.65 20.000.3 0 128.17 67.75 1566.42 840.39 71.83 48.92 43.96 27.79 38.37 53.65 16.000.4 0 128.17 67.75 1566.42 840.39 66.02 47.67 48.49 29.64 41.97 53.65 13.120.5 0 128.17 67.75 1566.42 840.39 62.5 46.86 51.24 30.83 44.18 53.65 11.050.6 0 128.17 67.75 1566.42 840.39 60.4 46.29 52.88 31.68 45.54 53.65 9.490.7 0 128.17 67.75 1566.42 840.39 58.91 45.83 54.04 32.35 46.54 53.65 8.320.8 0 128.17 67.75 1566.42 840.39 57.89 45.48 54.83 32.87 47.24 53.65 7.390.9 0 128.17 67.75 1566.42 840.39 57.17 45.23 55.40 33.24 47.73 53.65 6.631 0 128.17 67.75 1566.42 840.39 56.6 45.01 55.84 33.56 48.14 53.65 6.02

0.1 0.5 128.17 67.75 1566.42 840.39 96.13 50.64 25.00 25.25 25.09 53.65 31.380.2 0.5 128.17 67.75 1566.42 840.39 71.8 39.51 43.98 41.68 43.19 53.65 27.010.3 0.5 128.17 67.75 1566.42 840.39 55.5 31.06 56.70 54.15 55.82 53.65 23.270.4 0.5 128.17 67.75 1566.42 840.39 43.29 25.05 66.22 63.03 65.12 53.65 20.360.5 0.5 128.17 67.75 1566.42 840.39 34.3 20.32 73.24 70.01 72.12 53.65 18.040.6 0.5 128.17 67.75 1566.42 840.39 27.81 16.43 78.30 75.75 77.42 53.65 16.140.7 0.5 128.17 67.75 1566.42 840.39 23.01 13.44 82.05 80.16 81.40 53.65 14.540.8 0.5 128.17 67.75 1566.42 840.39 19.36 11.26 84.90 83.38 84.37 53.65 13.190.9 0.5 128.17 67.75 1566.42 840.39 16.52 9.58 87.11 85.86 86.68 53.65 12.051 0.5 128.17 67.75 1566.42 840.39 14.4 8.36 88.76 87.66 88.38 53.65 11.05

0.1 1 128.17 67.75 1566.42 840.39 93.5 46.8 27.05 30.92 28.39 53.65 35.510.2 1 128.17 67.75 1566.42 840.39 66.53 31.4 48.09 53.65 50.02 53.65 31.280.3 1 128.17 67.75 1566.42 840.39 46.64 21.85 63.61 67.75 65.04 53.65 27.120.4 1 128.17 67.75 1566.42 840.39 32.55 15.37 74.60 77.31 75.54 53.65 23.620.5 1 128.17 67.75 1566.42 840.39 22.68 10.84 82.30 84.00 82.89 53.65 20.740.6 1 128.17 67.75 1566.42 840.39 16.41 8.1 87.20 88.04 87.49 53.65 18.240.7 1 128.17 67.75 1566.42 840.39 12.39 6.25 90.33 90.77 90.49 53.65 16.170.8 1 128.17 67.75 1566.42 840.39 9.88 5.33 92.29 92.13 92.24 53.65 14.420.9 1 128.17 67.75 1566.42 840.39 8.25 4.62 93.56 93.18 93.43 53.65 12.981 1 128.17 67.75 1566.42 840.39 7.38 4.02 94.24 94.07 94.18 53.65 11.78

0.1 2 128.17 67.75 1566.42 840.39 90.18 41.59 29.64 38.61 32.74 53.65 40.950.2 2 128.17 67.75 1566.42 840.39 61.1 25 52.33 63.10 56.05 53.65 35.050.3 2 128.17 67.75 1566.42 840.39 39.09 14.79 69.50 78.17 72.50 53.65 30.230.4 2 128.17 67.75 1566.42 840.39 25.17 9.79 80.36 85.55 82.16 53.65 25.690.5 2 128.17 67.75 1566.42 840.39 16.15 6.49 87.40 90.42 88.44 53.65 22.120.6 2 128.17 67.75 1566.42 840.39 11.03 4.42 91.39 93.48 92.11 53.65 19.200.7 2 128.17 67.75 1566.42 840.39 7.73 2.84 93.97 95.81 94.60 53.65 16.900.8 2 128.17 67.75 1566.42 840.39 5.97 2.13 95.34 96.86 95.87 53.65 14.990.9 2 128.17 67.75 1566.42 840.39 4.76 1.52 96.29 97.76 96.79 53.65 13.451 2 128.17 67.75 1566.42 840.39 4.07 1.1 96.82 98.38 97.36 53.65 12.18

0.1 3 128.17 67.75 1566.42 840.39 87.88 39.44 31.43 41.79 35.01 53.65 43.790.2 3 128.17 67.75 1566.42 840.39 57.06 22.53 55.48 66.75 59.38 53.65 37.130.3 3 128.17 67.75 1566.42 840.39 34.39 12.1 73.17 82.14 76.27 53.65 31.800.4 3 128.17 67.75 1566.42 840.39 21.12 7.72 83.52 88.61 85.28 53.65 26.670.5 3 128.17 67.75 1566.42 840.39 13.12 4.47 89.76 93.40 91.02 53.65 22.770.6 3 128.17 67.75 1566.42 840.39 8.43 2.02 93.42 97.02 94.67 53.65 19.730.7 3 128.17 67.75 1566.42 840.39 5.64 0.96 95.60 98.58 96.63 53.65 17.270.8 3 128.17 67.75 1566.42 840.39 4.17 0.37 96.75 99.45 97.68 53.65 15.270.9 3 128.17 67.75 1566.42 840.39 2.96 0.22 97.69 99.68 98.38 53.65 13.671 3 128.17 67.75 1566.42 840.39 2.07 0.21 98.38 99.69 98.84 53.65 12.36


heating+cooling are calculated for different collector areas (1st column) and storage sizes (2nd column) based on the simulation results.

Figure 6 – ExCel-Diagram ‘SFC_eta’ in the work sheet ‘Postprocessor_SolarCoolingLight.xls’. Solar fraction for cooling and net collector efficiency are shown for different collector areas (x-axis) and storage sizes (curves). Example: specific collector area of 0.2 means 0.2 m2 of collector per m2 of room. SF-0.5 means the solar fraction for a storage size of 0.5 kWh per m2 of collector. eta-0.5 means the net collector efficiency for a storage size of 0.5 kWh per m2 of collector.

0

20

40

60

80

100

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Specific collector area, m2/m2

So

lar

frac

tio

n c

oo

ling

, %

0

10

20

30

40

50

Net

co

llect

or

effi

cien

cy,

%

SF-0 SF-0.5 SF-1 SF-2 SF-3eta-0 eta-0.5 eta-1 eta-2 eta-3


Figure 7 – ExCel-Diagram ‘Dia_1h’ in the work sheet ‘Postprocessor_SolarCoolingLight.xls’: Hourly required heat (Wh per m2 of room) for heating (t) or cooling (Q) versus hourly solar gains. Each line stands for a certain value of the specific collector area AA (m2 collector per m2 room area). A dot below the line demonstrates a situation in which solar gains exceed the actual required heat. A dot above the line demonstrates a situation in which solar gains are lower than the actual required heat.

All these indicators must help the engineer to pre-size some parameters : type and collector area, storage size.


2/ SYSTEM SIZING 2.1/ Sizing data

SCENARIO 1 : UNDERSIZED SYSTEM USING AN ABSORPTION SYSTEM The target is : - produce cooling energy without significant storage, - use all the produced cold.

To reach this goal, the cooling power of the absorption machine must be less than the minimum cooling load.

SCENARIO 2 : OPTIMIZED SYSTEM USING DEC, AD- OR ABSORPTION CHILLERS

Notice : The following part of the guidelines until chapter 5 is based on the hypothesis of the choice of SCENARIO 1. For the studies using SCENARIO 2, a specific solar cooling sizing software is required. TRNSYS for example permits to do this work as well as SOLAC, a design tool which is the result of the work of the Subtask B of the IEA Task 25 (http://www.iea-shc-task25.org). This tool will be accessible on demand at this internet address in 2005. 2.2/ Chiller sizing

Description of the features of the chosen absorption chiller fitting with the minimum cooling load and in maximum operating conditions

- Cooling capacity - Chilled water temperature - Generator temperature - Inlet cooling temperature

Flowrates to respect :

- Evaporator flowrate - Generator flowrate

- Absorber/condensor flowrate 2.3/ Solar collectors

2.3.1/ Collector implementation

After consulting the architects (in the case of a new building), study of the available space :

- on the roofs (building, parking, etc...) - on the ground in a free and protected place

Estimation of the total area available with the orientations and tilt angle


Technical specifications of the suitable collectors (3 maximum to reduce the cases) : - gross and net absorber area - performance coefficients

2.3.2/ Maximum use of the collected solar energy

Economical interest & overheating problems for the collectors avoided.

Maximim heating power from the collectors in the following conditions :

- solar max. input: 1000 W, - max. external temperature : °C - max. outlet collector temperature : °C - collector efficiency : that means : - max. usable heating power : kW. On that basis with the following other max. conditions :

- generator temperature of °C, - condensor temperature of °C, - chilled water temperature of °C, - COP of the chiller of , this means a max. cooling capacity of kW , less to the minimum cooling load.

2.4/ Cooling tower (only for closed cycle technologies)

Open or closed according to the water quality.

Dimension features based on the maximum operating conditions:

- heat power to evacuate (max cooling capacity + max heat source power), - outlet cooling tower temperature, - humid bulb temperature, - water flowrate.

Addition potential of an anti-corrosive continuous treatment and an anti-alga discontinuous treatment.


3/ THERMAL BALANCE OF THE SOLAR SYSTEM

3.1/ Calculation method

SOLO method (from the CSTB, the French Scientific Center for Building Technologies) normally dedicated to solar thermal hot water systems and adapted here to solar cooling systems. Available online on the TECSOL website (www.tecsol.fr)

3.2/ Meteorological data

Choice of the reference meteo station .

External temperatures : (average daily values) (in °C) :

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

Solar irradiation : Data in Wh/m2.jour for a given orientation & tilt angle


3.3/ Data on "domestic hot water consumption"

“Cold water” temperature : The « cold water » temperature (return generator temperature) is fixed at °C

“Hot water” temperature : The value is approximated to °C so that the installation is never in over-production.

3.4/ Component features

Solar collectors :

Efficiency, area per unit.

3.5/ Presentation of the calculation results

Daily needs (in kWh/day).


Solar collector production (in kWh/day) :


• On the cooling period, global results (based on a cooling period from April to

October):


MONTH Nb days Solar Energy kWh/d

Solar Energy

kWh/month

Generator Energy

kWh/month

COP machine

Cooling energy produced

kWh/month

April 15

May 31

June 30

July 31

August 31

September 30

October 15

TOTAL

Collectors losses (non usable solar energy + distribution losses) estimated at 10%

of solar collected energy:

• generator energy = 0,90 x solar energy.

• Cooling energy = Average COP of the absorption chiller x generator

energy

• On the heating period : global results (based on a heating period from November to

March):

MONTH Nb days Solar Energy kWh/d

Solar Energy

kWh/month

November 15

December 31

Januar 30

Februar 31

March 31

TOTAL


4/ INSTALLATION & WORKING PRINCIPLES

4.1/ Installation principle

• Solar collectors :

- Location of th collectors

- Spacial repartition

- Architectural integration

- Piping description, insulation technology

• Primary solar loop :

- Power of the heat exchanger (optional); - Description of the components used in the loop (fluid, circulating pump,

valves…) • Secondary solar loop :

- Power of the buffer storage (optional); - Description of the components used in the loop (fluid, circulating pump,

valves…) • Generator loop :

- Description of the components used in the loop (fluid, circulating pump, valves…)

• Absorption chiller :

- Dimensions of the machine(s)

- Connection features with the different loops

• Evaporator loop :

- Description of the components used in the loop (fluid, circulating pump, valves…)

• Cooling tower – condensor loop :

- Cooling tower description - Description of the components used in the loop (fluid, circulating pump,

valves…)

4.2/ Working principle

• Primary solar loop : starting & stopping conditions for the circulating pump (solar sensor for example).


• Secondary loop : starting & stopping conditions for the circulating pump (temperature difference for example) • Chiller : regulation strategy linked with the manufacturer specifications

• Cooling tower : regulation strategy linked with the manufacturer & chiller

specifications


5/ SYSTEM TELEMONITORING 5.1/ Functions of the telemonitor

The function of a telemonitoring apparatus that can be questioned at a distance by telephone is twofold: - ensure a permanent control of the solar installation performance and the working order of the different components, - inform the system manager immediately in the case of a breakdown or a failure of one of the components. For these reasons, it is an essential tool needed to obtain “guaranteed” results

5.2/ Description of the measurments

Depending on the system architecture 5.3/ Monitoring

The datalogger will be questioned every week, the collected data will be stocked and processed. The processed data will be published at the end of each month in the form of a statement that will be sent to all the partners. The purpose of this “solar statement” is to materialize the energetic performance and the conventional energy savings.


6/ ECONOMICAL BALANCE

6.1/ Evaluation of the cost of the project

- Collectors - Piping, primary loop accessories - Heat exchanger - Piping, secondary loop accessories - Piping, generator loop accessories - Chiller(s) - Cooling tower - Piping, condensor loop accessories - Piping, evaporator loop accessories - Set-up material - Management - Telemonitoring - Checkings, maintenance ____________

TOTAL WORKS………………..…………………………………………

• Engineering and telemonitoring actions on several years (3 to 5 years) ... _____________

TOTAL GENERAL Notice : in the cost of the proejct, the distribution network and terminals is not included. This is due to the fact that in any solution (solar or other), this part is compulsory and represents nearly the same cost.

6.2/ Evaluation of the annual savings

♦ Cost of the primary energy savings :

The reference solution to calculate the savings is based on the technology which would be used if the solar system was not implemented.

• Summer : Electricity, Fuel, gas.

⇒ Cost of useful kWh (in c€)

• Winter : Electricity, Fuel, gas

⇒ Cost of useful kWh (in c€)

For a reference solution, the cost of useful kWh includes the cost of primary energy and the efficiency of the reference solution to produce 1 kWh of cold or heat. This cost does not include the cost of the auxillary consumptions (electricity, water) because the total consumption per kWh is nearly the same between the reference solutions and the solar one. An exception is to be noted with an air/air electric system. It does not require water consumption but this product has to be replaced after 10 years (20 years for a solar or gas system). So, if this replacement cost is considered as damping, it widely covers the water consumption cost.


The costs of operation and maintenance are not included as well in the calculation of primary energy savings because the level per installed kW is nearly the same for all the solutions (gas, electric and solar).

• Useful solar energy : This represents the amount of energy produced by the solar system and available for the load (cooling and heating energy)

- Winter : kWh - Summer : kWh

♦ Annual savings :

• Cooling energy cost (summer) : € / an (value obtained by : useful solar cooling energy x cost of useful kWh)

• Heating energy cost (winter) : € / an (value obtained by : useful solar heating energy x cost of useful kWh)

⇒ TOTAL ANNUAL SAVINGS : ……….…………. €

The amount of saved energy is quantified because it represents the gain between a solar system and a reference one. Indeed, in the majority of the cases, the investment of a conventionnal solution as a back up is however necessary to face the load when the sun is not present. So, it can not be considered as a kind of saving.

6.3/ Overcost evaluation

The reference solution to calculate the overcost of the solar system is based on the technology which would be used if the solar system was not implemented. An equivalent service must be done. For example, this can correspond to an electric heat pump (able to produce cold in summer and heat in winter ) or an gas absorption system (with an absorption machine and a boiler). A single compression non reversible system can not be considered as a reference solution. To consider the solar system overcost, the cost of the project must be decreased of the value of the reference solution cost. SOLAR OVERCOST = SOLAR PROJECT COST – REFERENCE SOLUTION COST Notice : in the solar cooling projects, the working and maintenance costs are not taken into account because they are estimated to be at the level of the ones of a reference solution.


6.4/ Grants

Without financial incentives, solar-assisted air-conditioning cannot, for the time being - given the energy prices and system component costs that were used - be economically competitive to conventional systems. However, with funds that support energy-saving measures and the use of systems that exploit renewable energy sources - as are available in several countries - solar-assisted air-conditioning become financially competitive, and can be considered a promising approach for the future. The grant level is generally calculated with a ratio of the solar overcost of the project. Some European rules are managing the maximum levels so as to limit excess and non-concurrency cases. The final solar project cost can be obtained with the initial cost decreased with the financial incentives. A notion of pay back can be thus integrated by dividing this final cost by the annual energy savings.


7/ ENVIRONMENTAL ADVANTAGES The CO2 production due to primary energy production is contributing at the level of 50% to the greenhouse effect. Amount of tons of avoided CO2 emission thanks to the solar cooling system. Saving in primary energy. A example of such a comparison with traditional thermal systems is shown in the following pictures :

Figure 8 – Comparison on primary energy between traditionnal thermal system and solar cooling system

The two pictures show the COP based on primary energy. On the top, a comparison between an electric system and a gas system and on the bottom, a comparison between an electric system and an hybrid solar/gas system. The COP is far better for the solar/gas system.

Compression gas Sorption

88

100 100

82

49

34

29

81

Gas burner

Turbo-alternator

Transportation

0,6

2,8

0,820,88

0,38

COP_PE = 0.81COP_PE = 0.49

Compression system

Absorption machine


88

100 100

82

49

34

29

81

Gas burner

Turbo-alternator

Transportation

0,6

2,8

0,820,88

0,38

COP_PE = 0.81COP_PE = 0.49

Compression system

Absorption machine


88

100 50

41

49

34

29

81

0,6

2,8

0,820,88

0,38

solar41

COP_PE = 0.81

COP_PE = 0.98

Gas burner

Turbo-alternator

Transportation

Compression system

Absorption machine


88

100 50

41

49

34

29

81

0,6

2,8

0,820,88

0,38

solar41

COP_PE = 0.81

COP_PE = 0.98

Gas burner

Turbo-alternator

Transportation

Compression system

Absorption machine

Analysis of the feasibility studies page 24

B. Analysis of the CLIMASOL feasibility studies 1/ INTRODUCTION

The analysis of existing installations has enabled the “Promoting solar Air-Conditioning” project participants (9 participants from 7 different countries) to identify a certain number of conditions that are favourable to the success of solar air conditioning projects, and to define criteria for the research of potential sites, either new or in building in a retrofitting process. “Targets” for solar air conditioning have been defined. Three existing or projected buildings have been selected from these criteria in each country (except for Germany with only 2 sites), and a feasibility study carried out for each one.

Each partner was responsible for the research of the sites in their country and for the quality of the studies. The aim was to be able to have demonstration set-ups in each country that can serve as an example for other building owners.

Some difficulties were encountered to make these studies. The first problem was to find building owners ready to pay for a feasibility study. In countries such as France were the studies are partially supported by public fundings, the research was easier. Finally, all the planned studies have been found. Another difficulty has been to quantify the cooling load and then size the solar cooling system. A few software or tools easy to use are adapted to this target. Indeed, the sizing phase must be done on energy and not on power because the sun irradiation is changing during the day and the season (contrary to gas or electricity). This trouble could partially solved thanks to simple tools such as the SACE tool described in this Guideline. 2/ MAIN DESCRIPTION OF THE STUDIES The participants per country involved in the production of the feasibility studies are the following :

- Austria : ESV - France : RAEE & TECSOL - Germany : FhG - ISE & BE - Greece : CRES - Italy : Punti Energia - Portugal : AMES - Spain : EVE

In total, 21 studies were done : 3 per each country, except 2 for Germany and 4 for France. The feasibility studies has been made, respecting the following plan : 1. Data on the project – orientation of the study

1.1 General presentation of the project 1.2 Existing cooling and heating equipment 1.3 Orientation of the study

2. Targeted building description


2.1 Building structure 2.2 Occupancy 2.3 Conclusions

3. Impact of the improvement of the energetic quality of the building 3.1 Building modelling for intial conditions 3.2 Building modelling with passive techniques (eg. night ventilation)

4. Installation sizing 4.1 Sizing data 4.2 Solar sorption system sizing 4.3 Solar collectors 4.4 Cooling tower (for ab- or adsorption systems) 4.5 Technical premices

5. Thermal balance for solar production 5.1 Calculation methods 5.2 Meteorological data 5.3 Components features 5.4 Calculation results for solar cooling production 5.5 Calculation results for solar heating production 5.7 Calculation results for solar hot water production 5.8 Conclusion

6. Installation and working principle 6.1 Installation principle 6.2 Working principle

7. Telemonitoring 7.1 Telemonitoring objectives 7.2 Measurement description

8. Economical data 8.1 Project cost evaluation 8.2 Solar overcost evaluation 8.3 Yearly energy savings evaluation 8.4 Subsidies

9. Environment benefit A large variety of targeted buildings is presented in these studies :

- 10 office buildings - 2 churches - 3 laboratories - 1 sport centre - 1 hotel - 1 factory - 1 swimming pool - 1 single family house - 1 school

Different technologies are studied : absorption, adsorption and desiccant evaporative

cooling. The solar cooling power range is from 10 to 285 kW. At the same time, the cooled


area of each project is from 80 m² up to 12 000 m². Of course, the solar cooling penetration rate is different from one project to the others. That is why a statistical analysis of the results is necessary in the following chapter

Figure 9 – Building and solar cooling system description

3/ STATISTICAL ANALYSIS OF THE STUDIES

3.1/ Technical parameters Cold production technology : The first criteria to classify the different project is the technology of cold production : absorption, adsorption and DEC. The following chart is showing the repartition :

Country Location ApplicationBuilding

cooled area

AB. : AbsorptionAD. : AdsorptionDEC : Dessicant

Cooling capacity

(kW)

Collector type : SAC, FPC, VTC,

CPC

Gross collector area

(m²)

Berlin office building 1200 AB 40 VTC 120

München office building 5800 AB 200 VTC 580

Chrissopigi church 500 AB 35 VTC 70

Athens laboratory 310 AB 35 VTC 140

Marathon hotel 80 DEC 9.5 FPC 45Bilbao office building 12000 AB 176 VTC 770

Bilbaonew office building

2600 AB 105 VTC 310

Leioa sport centre 600 AB 70 VTC 385Sintra office building 3000 AB 150 CPC 135Sintra office building 4000 AB 282 CPC 210Sintra swimming pool 600 AB 70 CPC 170Seriate church 1500 AB 70 FPC + VTC 290 (67+223)Povegnano office building 550 AD 35 CPC 60Milano office building 412 AD 10 VTC 22

Theningsingle family house

180 AB 15 FPC 74

Wels technical college 240 AB 15 VTC/FPC 65

Schlierbach metal industry 3000 AB 15 FPC 73Valence office building 450 AB 35 VTC 116St Etienne office building 230 AB 8.6 VTC 36Vaulx en Velin laboratory 700 DEC 35 FPC 50St Martin d'Heres laboratory 1100 AB 35 VTC 119

GERMANY

ITALY

AUSTRIA

FRANCE

GREECE

SPAIN

PORTUGAL


Figure 10 – Sorption technology repartition in the feasibility studies

The principal technology is absorption with more than 80% (17 FS) of the feasibility studies. This leading position is well in accordance with the existing solar cooling systems in Europe : the proportion reaches 60%. The explanation of such dominating position is mainly due to the majority of centralised cooling distribution systems made of chilled water instead of cold air, especiallly in Mediterranean countries. Type of solar collectors : Three kind of solar collectors are used for the systems :

- flat plate collectors (FPC) ; - vacuum tube collectors (VTC) - compound parabolic collectors (CPC)

The following chart is showing the repartition :

VTC57%

FPC26%

CPC17%

VTC FPC CPC

Figure 11 – Repartition of the solar collector technology in the projects.

17

22

Absorption Adsorption DEC


The technology with Vaccum Tube Collectors is the most represented with 57% of the projects (13 projects). It is to note that for one project, two technologies are used at the same time : FPC and VTC. But most generally, only one technology is studied and preferred. The most experimented and used pair is VTC and absorption while DEC is majoritairely used with FPC. Solar cooling capacity :

0

50

100

150

200

250

300

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Solar cooling capacity (kW)

Figure 12 – Solar cooling capacities for the different projects The average cooling capacity is 68 kW and 80% of the projects are working on solar cooling capacities of less than 110 kW. The minimum value is 8,6 kW and the maximum one is 282 kW. The repartition into the power ranges is the following : 0-30 kW : 6 projects ; 30 – 60 kW : 7 projects and > 60 kW : 8 projects. Solar collector gross area :

0100200300400500600700800900

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Solar collector gross area (m²)

Figure 13 – Solar collector gross area for the different projects


The average area is 184 m² and 75% of the projects are designed with areas of less than 200 m². The minimum value is 22 m²and the maximum one is 770 m². Solar collector gross area / solar cooling capacity ratio : An interesting link can be made between the cooling capacity and the collector area. The following chart is showing for all the case studies in each country these different data and the ratio between the collector area and the cooling capacity :

AB. : Absorption AD. : Adsorption DEC : Dessicant

Cooling capacity

(kW)

Collector type

Collector gross area

(m²)

Ratio Area/capacity

(m²/kW)

AB 40 VTC 120 3.0 GERMANY

AB 200 VTC 580 2.9 AB 35 VTC 70 2.0 AB 35 VTC 140 4.0 GREECE

DEC 9.5 FPC 45 4.7 AB 176 VTC 770 4.4 AB 105 VTC 310 3.0 SPAIN AB 70 VTC 385 5.5 AB 150 CPC 135 0.9 AB 282 CPC 210 0.7 PORTUGAL AB 70 CPC 170 2.4 AB 70 FPC + VTC 290 4.1 AD 35 CPC 60 1.7 ITALY AD 10 VTC 22 2.2 AB 15 FPC 74 4.9 AB 15 VTC/FPC 65 4.3 AUSTRIA AB 15 FPC 73 4.9 AB 35 VTC 116 3.3 AB 8.6 VTC 36 4.2

DEC 35 FPC 50 1.4 FRANCE

AB 35 VTC 119 3.4

Figure 14 – Technical data on the 21 projects The collector area/cooling capacity ratio average is 3,2. A precision has to be given : by solar collector gross area is meant the area occupied by the entire collector. It is different from the useful or net area which corresponds to the area of the absorption structure of the collector. As systems using absorption chillers and vacuum tube collectors are representing the majority of the studies, the average value of 3,5 can be a very good number for the ratio collector gross area / solar cooling capacity. A small number of systems have values of less than 1. This means finally a small solar fraction and the presence of a important back-up. The strategy is to participate to the cold production but at a low level. The solar fraction in this case can reach 10%. At the opposite, some values are of more than 5. This high value can have several reasons : wish of high solar fraction, possibility to use the solar energy in other applications than only


solar cooling, relative low efficiency of the solar collector field because of non optimal orientation or tilt angle. Annual cold production estimation / solar cooling capacity ratio : This ratio represents the number of hours in the year at nominal cooling capacity for the solar cooling system. The average on the 21 studies is of nearly 650 hours. This number could represent a good key for solar cooling system sizing in a first approach.

0

200

400

600

800

1000

1200

1400

1600

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Annual cold production estimation/ cooling capacity ratio (h)

Figure 15 – Annual cold production estimation /cooling capacity ratio for the 21 projects

Solar cooling fraction :

Figure 16 – Solar cooling fraction for the 21 projects

0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Solar cooling fraction


This notion of solar cooling fraction means the ratio between the cooling load of the

building (in kWh) and the solar cooling production (in kWh as well) in a cooling season. The analysis of the repartition of the fraction on the different projects underlines the

fact that different strategies are adopted. 5 studies show a fraction of 100% : this means that there is no back up and that the cooling load have no precise quantitative value. The comfort conditions are reached with the temperature decrease due to the solar system. This concept involves an important tolerance level from the building’s users. In the case of a low solar cooling fraction (i.e less than 10%), the solar cooling system is generally a part of a large traditionnal cooling network. It has a function of pre-cooling and is never sufficient to face the load.

More generally, every solar cooling system must be able to valorize all the solar cooling energy produced. So, two strategies are possible : for one thing, there are strict comfort conditions and the solar cooling energy is always less importan than the cooling load, avoiding solar energy in surplus. For another thing, if there is no strict comfort conditions, the solar cooling system can be alone to cool the ambiance of the building when the weather is sunny. Back-up system :

Figure 17 – Back up technology repartition for the 21 projects

In the case of a use of a back up system, two principal strategies are used : a hot back

up system, mainly with gas (1 project with wood and 1 with a district heating network). This heating source can be generally connected to the solar absorption chiller or to another one. For the cold back up system, the wide majority is made from compression chillers. The most relevant strategy in this case is to consider the solar cooling system as a pre-cooling one and to connect the electric compression device in serie to fill the needs of the load. A majority of gas back up are used (52%) because this technology permits to do as well heating as cooling with a good flexibility. 3.2/ Economical parameters

7

11

12

Electricity Gas Wood Others


Cost of the solar system : The analysis of the cost of the 21 studied projects makes appear a wide range because of the different sizes of the systems. The average cost is of 146 000 €. The lowest cost is of 15 000 € and the bigest is of 756 500 €. The cost of a solar cooling system is generally including (without tax) : solar collectors, piping, hydraulics, control, sorption machine, storages (buffer, hot or cold storage), monitoring and engineering. The distribution system is not included, being generally the same as for a traditionnal system. An interesting ratio to calculate is the solar cooling system cost by the collector area (picture below). This shows, that except one value (for an experimental DEC system), nearly all the projects have a cost between 500 and 1000 €/m². The average value is of 920 €/m². This number can be a good basis for sizing middle range solar cooling system (35-100 kW).

0

500

1000

1500

2000

2500

3000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

€/m

2 (c

olle

cto

r g

ross

are

a)

Figure 18 – Solar cooling project cost on the collector area ratio for the 21 projects

Overcost of the solar system (compared to a traditionnal solution): In each project, a solar overcost can be calculated : this represents the difference between the total solar cooling project cost and the cost of a traditionnal solution permitting to give the same result. This notion is important because it allows to obtain the payback time of the solar system by dividing this overcost with the annual energy savings. In addition, this overcost is the basis to calculate the amount of invesmtent subsidies in several countries (for example in France). This overcost is in any case a percentage of the total solar cooling system cost. The following figure shows the large distribution of such an overcost.


0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1

3

5

7

9

11

13

15

17

19

21

Figure 19 – Solar overcost on total solar cost system ratio for 19 projects (data for 2 projects missing)

Subsidies : On the 21 projects, 9 are susceptible to benefit from grants. These subsidies are particular to Germany, Spain and France and are planned to help the development of demonstration project using solar energy such as solar cooling projects. The level of subsidies is from 26 to 70% of the investment cost.

3.3/ Environmental benefits Avoided C02 emission : In each project, a quantity of CO2 avoided emission was calculated. The total quantity for the 21 project is reaching the value of 360 tons. The average value per project is of 17 tons.


4/ CONCLUSION AND FUTURE OF THE STUDIED PROJECTS All of the 21 feasibility studies were done for a large variety of buildings. The question of the future of the projects were asked by each participant of the project at the end of the CLIMASOL project in Aprirl/May 2005feasibility studies. The picture based on these returns is quite positive. As indicated also in the project specific performance indicators in two cases the studies have led to the construction of a solar cooling plant. This is the case in Austria and in Italy. In the majority of the cases, no precise answer could be given. The situation in France is also promising as Nevertheless, especially in France the building owner can count on a where specific investment supports can be attributed,. For two 3 projects a positive decision has been taken. In two other countries, Greece and Italy, this is also the case. are ongoing for the year 2005. In other countries such as Austria, one project is optimistically on a good way for a close future. For the rest two-thirds of the feasibility studies the follow up is much more uncertain. This is mainly due to The reason why so few answers could be given on the possibility to realize the operations is the lack of visibility on possible national or European grants for the building owner. Indeed, the overcost of the solar systems are quite always large high in comparison with traditionnal solutions ones and the project will be carried out are possible only if support helps can fill in the financial gap.

The initial goal of 13 realisations on the 21 studies could not be achieved in a short term, but thiese studies have permitted allowed to have in the participating countries theorietical case studies. This will give additional support material for convincing and motivating the potential building owners.

Among the 21 studies, 6 studies are presented with more detail in the annex because they are well representing the diversity of sorption technologies, countries, applications (hotel, office, industry…), and sizes, and different applicationsI n the majority of the cases, no precise answer could be given. The situation in France is also promising as the building owner can count on a where specific investment supports can ANNEX : DETAILED PRESENTATION OF 6 REPRESENTING CASE STUDIES A) DEC system (9,5 kW) : Conference room (Marathon, Greece) B) Absorption system (8,6 kW) : Office building (St Etienne, France) C) Absorption system (200 kW) : Office building (München, Germany) D) Adsorption system (10 kW): Office building (Milano, Italy) E) Absorption system (15 kW) : Metal Industry (Schlierbach, Austria) F) Absorption system (35 kW) : Laboratory (Grenoble, France)

FRAMEWORK FOR

FEASIBILITY STUDIES

1. Data on the project – orientation of the study

1.1 General presentation of the project The hotel is situated Nea Makri, Attica, Greece. It has 144 rooms, 3670 m² inhabited area and a conference room, situated roof garden, of 80 m² surface to be climatised by solar energy. In the photos below we may observe the entrance of the lobby of the hotel as well as its terrace, where solar collectors are to be placed for the solar cooling system under design.

1.2 Existing cooling and heating equipment Two years ago, the hotel changed the reciprocating compression air conditioning central system into VRV system, which is able to provide heating as well. The required heating loads are restricted to a minimum value, since the hotel for the moment is seasonal performance (only summer operation extended period sometimes) The installed cooling capacity is equal to 120 RT (420 kW). LPG is used for the hot water production. For a conference room to be installed besides the roof garden, under design, there is no cooling system designed yet. 1.3 Orientation of the study

There is need of a system which uses solar energy for winter operation and able to give any cooling load during summer with a back up based LPG.


2.1 Building structure Heavy weight structure is applied. Windows glazing is double. There exists insulation on the roof. 144 indoor units, split to 15 outdoor VRV units have a cooling capacity of 120 RT. Using VRV units the hotel director pretends an energy saving level equal to 25% (compared to the previous reciprocating and low efficient chillers-water cooled) 2.2 Occupancy The mean occupancy, 6 month based, is 45%. The director targets at a 12month occupancy equal to 70%. 2.3 Conclusions

Since the conference room will de deserved by a hybrid (FCU for space loads and pre-climatised air for the fresh air intake) system, we oriented the study to put VRV system for FCU for space loads and deciccant evaporative cooling for the fresh air intake, where soalr energy will regenerate.

3. Impact of the improvement of the energetic quality of the building

3.1 Building modeling for initial conditions The solar system will supply cooling and space heating locally to a conference room situated on the roof top. 3.2 Building modeling with passive techniques (eg. night ventilation) A retrofitting with double glazing to the doors of the rooms as well as to the glazing of the lobby area is foreseen.

4. Installation sizing

4.1 Sizing data

The room is sized 13x6x3 m3.It is foreseen to receive 40 persons at maximum. The load for heating is 8,75 Mcal/h and it is calculated according DIN77. The design temperatures are 20°C (room inside) and 3°C (outdoor) The cooling load is calculated approximately 9,24 kW. The design temperatures are 27°C & 50% (room inside) and 33,2°C ±10 K (outdoor for 23rd July) The above fresh air loads correspond to ach 5,7 (air changes per hour), or a fresh air intake equal to 20 cfm (33,8 m3/h) per person. We suppose a 3hour conference or meeting every day while the room will be open (and climatised) 8 hour a day. A hot water production is planed for the needs of the catering process in the nearby kitchen. We estimated these needs for hot water production equal to 500 lit/day. 4.2 Solar system sizing

According to the fresh air needs, an air handling unit with air flow rate of 1350 m3/h will be selected, equipped with both heat recovery heat exchanger and desiccant wheel. 4.3 Solar collectors There is shortage of space to install the solar collectors which are selected flat plate and this is why we faced to install them as a solar roof solution, oriented to the west (azimuth angle -900 ). The solar system is to compare with the “reference” conventional solution of a boiler for space heating and hot water production and of a chiller for the space cooling. The surface of collectors is 40m², therefore 50% of the climatised area. 4.4 Cooling tower (for ab or adsorption systems)

Not needed, since desiccant system. 4.5 Technical premises Roof area is restricted down to 40 m². Room available exists in a corner of the conference room and is restricted to 3 m². An air handling unit with air flow rate of 1350 m3/h will be equipped with both heat recovery heat exchanger and desiccant wheel. A second recovery possibility is drawn from the exhaust air discharge from the desiccant wheel to the incoming fresh water in the hot water storage tank.

5. Thermal balance for solar production

5.1 Calculation methods

For the study of the solar cooling system, desiccant evaporative, we have run four software: SACE, TSOL, 4M and SECO.exe, with:

• Operation temperature space heating 45°C • Operation temperature cooling 70°C

5.2 Meteorological data

Data base of SACE concerning Athens and lecture room. 5.3 Components features

Collector type FPC Optical efficiency 0,78 Linear loss coefficient 3,8 W/m2K Quadratic loss coefficient 0,03W/m2K2 Solar collector area against climatized area 0,5 Efficiency of heating system 0,85 Efficiency of DEC-cooling system 0,55 Time equivalent of the storage volume 1 hour 5.4 Calculation results for solar cooling production

Amount of heat for cooling, reference to m2 room 50,4 kWh/m2 Solar fraction cooling 70 % The solar system will supply fresh air loads The remaining space cooling load (up to the 11 kW) is covered by a small conventional electrically driven chiller sized 4RT. 5.5 Calculation results for solar heating production Amount of heat for heating, reference to m2 room 28,8 kWh/m2 Solar fraction SPACE heating 66 % A large amount of solar hot water is produced and can let the collector achieve larger collector efficiencies 5.7 Calculation results for solar hot water production

Annual needs for hot water production 6357 kWh/y Delivered by the solar collector 6357 kWh/y 5.8 Conclusion Amount of heat energy for space cooling 5781 kWh/y Amount of electric energy for space cooling, if conventional 1514 kWh/y Amount of energy for space heating 4664 kWh/y Amount of energy for SHW heating 6357 kWh/y

Amount of back-up energy for space cooling 1749 kWh/y Amount of electric back-up energy for space cooling, 0 kWh/y Amount of back-up energy for space heating 1194 kWh/y Amount of back-up energy for SHW heating 0 kWh/y

6. Installation and working principle

6.1 Installation principle

The cooling system is based on the solar assisted evaporative cooling in a desiccant air supply and we have a small conventional backup, oil fired. The solar collector field, sized 40m², produces hot water around the year, which will be supplied to the kitchen/restaurant for the hot water needs of the catering process A desiccant evaporative cooling air handling unit selected, sized 1350 m3/h, equipped with an additional air to water heat recovery coil, which preheats the fresh water in to the hot water storage tank before it is heated by the solar system 6.2 Working principle Space cooling The hot water from solar collectors (appr. 75°C) feeds the regenerating coil of the air handling unit. A 2000 lit buffer permits to the storage of heat able to cover the cooling load during 1 hour. A desiccant wheel, 1350 m3/h, technology SECO, dries the outdoor air, so the latest is able to be cooled down effectively due the water spray unit (by the evaporative effect). A new section of the air handler contains a heat recovery pre-cooler of the fresh air intake, by recovering the cold energy from the exhaust air side. No cooling tower is needed. Nevertheless, make up water flow is necessary and important SHW production The water intake goes first through the recovery coil in the air handler and then to the storage tank. The solar heat is kept from the buffer to the storage tank via a plate heat exchanger. Finally, a conventional boiler (back up) using a new heat exchanger, gives the necessary heat to achieve the final temperature required at the water supply.

7. Telemonitoring 7.1 Telemonitoring objectives

Not yet suggested 7.2 Measurment description

Not yet suggested

8. Economical data

8.1 Project cost evaluation

COP Cost

CHI-Electric chiller (COP=2,8/3,1) 2.64 RT 2.8 5282.5 10 RT 3.1 L/K-Oil burner 8.75 Mcal/h 1500.0

ΚΚΜ-Air Handling Unit 1352 m3/h 3000.0 Installation 2.5 RT 2000.0

TOTAL 11782.5 8.2 Solar overcost evaluation

COP Cost (€) Flat plate collectors 40 m2 8000.0 Storage tank 2000 lit 2000.0 Oil burner 14.45 Mcal/h 2479.0 ΚΚΜ-Air Handling Unit with desiccant wheel 1352 m3/h 0,55 10500.0 Installation 0 RT 2800.0

TOTAL 25779.0 Overcost evaluation 13 996 € 8.3 Yearly energy savings evaluation

Type of fuel

kWh/y saved

Price (€/kWh)

elecricity 1514 0,055 oil heating 2024 0,042 oil "motion" 7478 0,083

For the production of hot water in Greece we must use the “motion” oil which is more expensive than the oil for space heating. 8.4 Subsidies

Not yet sought

9. Environment benefit

Emissions of gases

Unitary values

amount (kg,

MWh)

Hu (kWh/kg) CO2 SO2 CO Nox HC particules TOTAL units

oil 1 11.92 3142 0.7 0.572 2.384 0.191 0.286 3146.133 g/kg electricity 1 1 850 15.5 0.18 1.2 0.05 0.80 867.73 kg/MWh

Reference A. Overall emissions of reference

oil 1087.76 11.92 3417.73 0.76 0.62 2.59 0.21 0.31 3422.22 kg i/y electricity 1.51 1.00 1286.99 23.47 0.27 1.82 0.08 1.21 1313.83 kg i/y

4736.06total kg/y

Solar cooling B. Overall emissions of solar cooling

oil 290.48 11.92 912.69 0.20 0.17 0.69 0.06 0.08 913.90 kg i/y electricity 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 kg i/y

913.90total kg/y

Annex 1 – Installation schemes Annex 2 – Calculations

FRAMEWORK FOR FEASIBILITY STUDIES


1.1 General presentation of the project Glaciology & Geophysics Laboratory (Saint Martin d’Hères) Rhône Alpes area (France) Total area of the building to cool : 1 100 m², on 3 levels. Office building built in 1982. Height per floor : 2,5 m. 1.2 Existing cooling and heating equipment No major cooling equipment (1 Split system for the manager room) except the cold rooms in the ground floor. 1.3 Orientation of the study

Cooling season between May and end of September. First priority for cooling : 1982 Building (1 100 m²). Heating in winter. No hot water needed. Excess of solar coolin used in a second building (built in 1973) nearby -> Solar absorption system (35 kW) chosen because no air distribution system adaptable for DEC.


2.1 Building structure Walls : concrete, internal insulation 100 mm. Ceiling : concrete, rockwool 100 mm, Windows : double glazed No forced ventilation system Solar protection on eastern and western facade Infiltration : 0,6 V/h

Roof : plate 2.2 Occupancy - 50 people in the 1st floor (400 m²). - Small office rooms (12 m²) with 2 to 3 researchers. - 3 laboratories on the ground floor and the cold rooms. Planning : 8h->12h & 14h->18h from Monday to Friday 2.3 Conclusions

Use of solar protection to be optimised. Add-in of a night ventilation device. 3. Impact of the improvement of the energetic quality of the building

3.1 Building modelling for intial conditions 3.2 Building modelling with passive techniques (eg. night ventilation) Night ventilation : 8 vol./h Optimal use of the solar protections Annual cooling load (for a normal year) at 27°C : 1 500 kWh Annual cooling load (for a special very hot year eg. 2003) at 27°C : 20 000 kWh Benefit of using solar protections but not sufficient : solar cooling required


4.1 Sizing data

Cooling load for the 1982 building for a hot season (2003) (instantaneous power in kW) Cooling needs first covred with solar cooling system (35-45 kW) : self-sufficient for a normal year Use of a back up for special hot years (2003) necessary for only a few days

Eté exceptionnel (2003) - LGGE

0

20

40

60

80

100

120

5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8 9 9 9 9 9 9 9 9Mois

(kW

)

Charge thermique

4.2 Solar sorption system sizing YAZAKI Absorption Chiller :

- Cooling power : 35 kW - Chilled water temp. : 7°C - Inlet generator temp. : 95°C - Inlet condensor temp. : 29,5°C - Evaporator flowrate : 6 m3/h - Generator flowrate : 8,5 m3/h - Absorber.condensor flowrate : 14,6 m3/h

4.3 Solar collectors 510 m² available on the plate roof of the 1973 building (see picture). 27 Evacuated tube collectors (Thermomax Mazdon) Absorber area per unit : 3,04 m² Total useful area : 82 m² Efficiency : • c0 = 0,798 • c1= 1,3 W/m².K. • c0= 0,0082 W/m².K². 4.4 Cooling tower

Open cooling tower Features : - Cooling power : 80 kW (35 kW + 45 kW), - Outlet temp. : 27°C, -Wet bulb temp. :22°C, - Flowrate : 14,6 m3/h. 4.5 Technical premices Located in northern part of the 1973 building, at immediate proximity of both the solar collector field (located in the 1973 building roof) and the cooling load (located in the 1982 building) just below the roof and on the top of the building. Dimensions : 5 x 2,5 x 2,5 m (L x w x h)


5.1 Calculation methods TRNSYS : hourly simulation for one year long of both the load (building) and the solar cooling system. 5.2 Meteorological data

Average monthly meteo data from GRENOBLE (temperature and irradiation). Sinusoidal extrapolation made by TRNSYS 5.3 Components features Presence of a 1 000 liters hot water buffer storage between the solar collector field and the absorption machine. 5.4 Calculation results for solar cooling production

Cooling load for the 1982 building (5 months of cooling season for an exceptionnal year) : 21 220 kWh Solar cold production : 19 610 kWh 5.5 Calculation results for solar heating production Heating load (7 months of heating season at 20°C) for the 1982 building : 423 700 kWh Solar heat production : 39 000 kWh 5.7 Calculation results for solar hot water production No hot water use.. 5.8 Conclusion

Total solar energy produced and used in the building : 58 610 kWh No need of a cooling back up system because the target is reached for a normal year : acceptable confort conditions for the 1982 building in summer. Excess of cooling energy is used in the 1973 building. For exceptionnal year, only a few days without respect of comfort conditions occur. Heating back up in winter : central conventionnal heating system.



6.2 Working principle Priority to the 1982 building. Cold production for the 1973 building otherwise No interruption of the system during the week end (to maintain comfort conditions for the monday)

7. Telemonitoring

7.1 Telemonitoring objectives To check the quality in the working of the installation, Capacity of a fast intervention in case of troubles.

7.2 Measurment description

Irradiance Solar collector loop energy Generator (or available for heatin) energy Evaporator energy Condensor energy State of the different pumps

8. Economical data


VE

RD

Circulateur

Clapet anti-retour(sens de circulation)

Vanne d'arrêt NO

Vanne d'arrêt NF

Soupape de sécurité

Cellule d'éclairement

Régulateur différentiel

Sonde

Purgeur d'air automatique

Compteur volumétrique àémetteur d'impulsions

Capteurs solaires

Eva Abs

Con

Gén

RDIC

Machine à absorption

Réseau ventiloconvecteursbâtiment 1982

80°C

29,5°C

Tour de refroidissement

VE

Ballontampon1 000 l

ProjetRafraîchissement solaire

TECSOLBP 434 - TECNOSUD - 66 004 PERPIGNANTél : 04.68.68.16.40 Fax : 04.68.68.16.41

Septembre 2004Schéma n° 2

Principe général rafraîchissement et chauffage solaire

arrêt : 80°Cmarche : 75°C

Arrivée réseau chaleurd'appoint optionnelle

LGGE - Rafraîchissement Bâtiment 1982 - Grenoble (38)

Retour circuiteau glacéebâtiment 1973

Ballon500 l

Retoureau glacéevers groupes froids2 x 100 kW

Limites prestation solaire

Technical premices Solar collector field + piping Primary loop Hot water buffer storage tank Absorption machine + generator loop Cooling tower + condensor loop Control + electricity Telemonitoring Engineering TOTAL Solar system cost : 112 000 € (without tax) Distribution network TOTAL cost estimation : 163 000 € (without tax)

8.2 Solar overcost evaluation

Electricity configuration (reversible compression chiller) : Cost of the compression chiller : 10 000 € Cost of the technical premices : 10 000 € Estimation of the overcost due to the solar system : 112 000 – 10 000 – 10 000 = 92 000 €

8.3 Yearly energy savings evaluation

Electricity useful kWh (including conversion efficiencies) : Useful kWh in summer : 0.0125 € Useful kWh in winter : 0,053 € TOTAL savings : 3 170 €/year

8.4 Subsidies

Level of subsidies avalaibable to support the project : 70 % (but not yet fixed) Final cost for the owner with deduction of the grants : 33 880 € (distribution network excluded) Payback time : 10,7 years

9. Environnment benefit Estimation of the CO2 avoided emissions :

16,1 tons compared to electricity : Annex 1 – Installation schemes

Localtechnique solaire

(emplacement provisoire)

Canalisations

LGGE - Rafraîchissement Bâtiment 1982 - Grenoble (38)


Implantation capteurs solaires et local technique

TECSOL BP 434 - TECNOSUD - 66 004 PERPIGNANTél : 04.68.68.16.40 Fax : 04.68.68.16.41

Septembre 2004Schéma n° 1

Détail local technique

4 m

2,5 m

N

S

E

O

N

S

E

O

Tour de refroidissement (emplacement provisoire)

Bâtiment 1973

Champ de capteurssolaires

Bâtiment cible 1982

Garage 1973

Local technique 1973

Groupes froids existants(2 x 100 kW)

Machineabsorption

Echangeur

hsp : 2,2 m

Ballontampon

Feasibility study

Solar Cooling

Metal industry Schlierbach

(Upper Austria)


1.1 General presentation of the project Main data of the project (owner of the building, size and kind of use of the building) Metal industry factory Schlierbach Upper Austria

Use of the building: 2000 m2: production of metal parts for die casting 2x 500 m2: offices 1.2 Existing cooling and heating equipment For existing buildings, description of the cooling and heating components Production and offices are heated by natural gas with high efficiency (use of the gross calorific value). Heat recovery is done from the compressed air unit and additionally with a air/air-heat exchanger. 300 m2 of the production area and 700 m2 of the offices are heated by a underfloor heating. Additional ventilators and radiators are in use. Cooling is needed for process-cooling of machines. The major part of the cooling is done by a water buffer tank with a capacity of 100 m3 and the tank is fed with cold water from the spring of the company. For the remaining demand an electric compression chiller with 35 kW cooling capacity is installed. 1.3 Orientation of the study

Principal wishes of the owner for the use of solar energy : which part of the building has to be cooled, how to valorize solar energy during winter (heating, hot water...) The owner is very much interested to use as less energy as possible and the energy which has to be used should be ecological and renewable.

The company produces high quality products, thus the owner and the managers are always interested in new intelligent technologies and techniques. Solar cooling would fit into this corporate philosophy. Solar cooling should replace the electric compression chiller and the additional solar yield should reduce the natural gas consumption for heating purposes.


2.1 Building structure Description of the building structure (walls, windows, lights, doors, infiltration and AHU systems). Division of the building into separated and independent zones

?? ferro-concrete ceilings ?? thermal insulation walls U=0,3 W/m²K ?? Offices with glass façade ?? windows: U = 1,1 W/m²K ?? lighting: high pressure mercury lamps in production area; fluorescent

lamps in offices ?? natural gas (high efficient by use of the gross calorific value), air/air heat

exchanger, heat recovery from compressed air system ?? under floor heating

2.2 Occupancy Typology of the existing or forecast occupancy per zone in the building Solar cooling should be used for process (machine) cooling. The production equipment produces about 100 kW of waste heat. Most of the cooling can be done by the spring. Only about 35 kW of cooling load must be performed by additional cooling with electrical compression or solar cooling with a thermal driven chiller.

2.3 Conclusions

Discussion on the energetical quality of building. Recommandations to improve this quality (solar protection to be added, roof insolation to increase, night ventilation...) The building is new and built according to the highest thermal standards. Heat recovery, heat exchange and efficient production of heat and cold yields to a very low overall energy consumption.


3.1 Building modelling for intial conditions

If possible, modelling of the building without passive techniques improvement and virtual temperature profile of the different zones. Quantification of the uncomfortable conditions level 3.2 Building modelling with passive techniques (eg. night ventilation) If possible, modelling of the building with passive techniques improvement and virtual temperature profile of the different zones. Quantification of the uncomfortable conditions level decrease. Necessity of the active techniques (solar cooling)


4.1 Sizing data

Load calculation and cooling strategy Cooling should be performed mainly by use of water from the spring. About 7 m3/h of cold water can be pumped out of the spring. This gives a cooling capacity of the spring of up to 75 kW. Only a maximum of 35 kW of additional cooling by use of electrical or thermal driven chillers is necessary. To obtain a system with high hours of operation, a 15 kW absorption cooling unit driven by solar energy is planned. 4.2 Solar sorption system sizing

Estimation of the nominal power requested for the sorption machine so as to fit the load as much as possible. 15 kW H2O/LiBr absorption cooling system 4.3 Solar collectors Estimation of the collector area requested so as to make work the machine. Study of the available space for collectors on the roof or on any other place near the targeted building. 65 m² flat plate collectors There is sufficient flat roof available for the installation of the collector system. 4.4 Cooling tower (for ab- or adsorption systems)

Estimation of the nominal power requested for the cooling tower and study of the available space to put this device. The cooling tower with a cooling capacity of 32 kW is planned. Problems of space or noise are not expected. 4.5 Technical premices

Description of the layout of the premices (dimensions, networks requested (electricity, water inputs and outputs). Study of the space requested for the installation of the technical premices. The two main assemblies, evaporator – absorber and generator – condenser, can be readily installed, wired and piped and connected by quick-disconnect couplings. The cabinet of the automatic control technology is also already produced by the factory. Furthermore, the plant consists also of:

?? solvent and refrigerant pumps ?? heat exchanger ?? ventilation system ?? control cabinet

Additional equipment is necessary like:

?? heat, cooling and cold water pumps buffer storage: The company has a 100 m3 buffer storage tank for the cold water. Heat from the solar collectors can be integrated and used directly for heating of the production area. The integration of the solar collector circle is done by external heat exchanger.


5.1 Calculation methods

Description of the main features of numerical tool or method to make the thermal balance. Assets and limits of the tool. The solar heat circle was calculated using the programme T*SOL. With this programme, particularly with the latest version, all components of the solar system and its basic conditions (consumer profile, temperatures, etc.) can be modified very well independently from each other - so that a simulation of the solar system for solar cooling can be done with sufficient accurateness. SACE Solar Cooling Light Computer Tool: The tool has the function to carry out a draft feasibility study in order to investigate the application of solar cooling for a given load file and a given solar collector. The tool uses a combined meteo-load-file as input (produced with TRNSYS or any other similar program) and a configuration file for definition of the system. Based on meteo-load-file and configuration of the system the annual solar fraction for heating and cooling is calculated based on an hour-by-hour comparison of needed heat for a thermal driven cooling and available solar heat.

A parametric study for different collector areas, expressed as specific collector area AA (m² of collector per m² of conditioned room), is automatically carried out. In order to assess the effect of storage, also different sizes of a system-integrated energy storage, expressed in h of peak cooling load, are considered. The storage is not modelled as a technical component, but simply as a buffer which enables the use of excess solar heat (or cold) of one hour in later hours in which the solar gains are not sufficient to match the load. A storage size of 1 hour means, that the peak cooling load of the entire year can be covered by the storage for one hour without any other energy input into the system. In a real system, storage can be integrated either on the hot side (storage of excess solar heat), on the cold side (storage of excess solar produced cold) or on the load side, e.g. using the building thermal mass.


Source of the meteo data and values used for the calculations T*SOL: The meteorological data are provided by the programme T*SOL and come from the Swiss programme Meteonorm. For the given plant in Schlierbach the meteorological data of Kremsmünster were used. SACE: The meteo-load file contains all information which is used to compute the hourly performance of the solar assisted air conditioning system. Any well-known building simulation tool with a radiation processor can be used in order to produce the file. In this case, a pre-defined meteo-load file for an lecture room with nearly the same load in Freiburg (Germany) was taken. This meteo-load file was developed in the framework of Task 25 Solar Assisted Air-Conditioning of Buildings of the Solar Heating and Cooling Programme of the International Energy Agency (IEA).

5.3 Components features

Description of the inputs for the model (compared to chapter 4., complementary information on components features) 5.4 Calculation results for solar cooling production

Results of the calculations to determine the solar cooling production. Solar cooling penetration rate. Impact on the temperature profiles in the building. Level of comfort reached in comparison with comfort conditions expected. Cooling production: 10 MWh 5.5 Calculation results for solar heating production

Results of the calculations to determine the solar heating production. Solar heating penetration rate. Impact on the temperature profiles in the building. Level of comfort reached in comparison with comfort conditions expected. No heating support is taken into account 5.7 Calculation results for solar hot water production

Results of the calculations to determine the solar hot water production. Solar penetration rate. Hot water production: 10 MWh 5.8 Conclusion Total solar energy produced and used in the building. Need of a back-up system. Proposal for the management of the back-up. Total solar energy production: 24,3 MWh Cooling production: 10 MWh As a back-up system the plant has an electric compression chiller for cooling and a natural gas heating system for the heating of the building and hot water production.



Description of the different parts of the solar system : type of pumps, estimated lenght and nature of the piping, ...etc Conventional components of the solar technology are used. Estimated length of the pipeline outdoors: 70 m Estimated length of the pipeline in the building: 20 m 6.2 Working principle Description of management of the system : control rules, hierarchy between the different uses of solar energy Hierarchy: If there is a cooling load, primary the cold water from the spring, buffered in the storage tank, is used. If the cooling demand is higher, the absorption cooling system produces the remaining cold. Whenever the solar collectors produce a surplus in energy which is not used in the absorption cooling system, this heat is used for hot water production. During the transitional period and wintertide, the priority is switched to hot water supply, whereas the collector fields are integrated in the hot water supply.

7. Telemonitoring

7.1 Telemonitoring objectives

Explanation of the objectives of telemonitoring : quality in the working of the installation, interest for a fast intervention in case of troubles. The objective of the installation of a cooling system driven by solar energy is to produce cheap and clean cold for the plant. Preliminary economical calculations show negativ results. To obtain a better economical result, the installation must be supported with subsidies. For this support the company offers information and practical experiences e.g.

- Proof of the operational and functional safety of the absorber and identification of improvement potentials

- Ratio of the different heat sources (solar heat, conventional heating) to ensure an economic cooling mode

- Collection of experiences during the layout and the operation of solar cooling systems

7.2 Measurement description

Basic description of the measurement points (sensors, flowmeters, energy)

Solar system:

?? external temperature sensor ?? irradiation sensor ?? primary flow temperature sensor ?? primary backward temperature sensor ?? primary flow rate counter ?? secondary flow temperature sensor ?? secondary backward temperature sensor ?? secondary flow rate counter ?? secondary heat flow counter for the buffer storage ?? secondary heat flow counter for the solar support of the hot water system

Absorption cooling machine:

?? pressure and temperature measurements at different points in the cooling cycle process to get specialized knowledge and to point out optimization steps

8. Economical data


List of the components included in the solar project. Cost estimation with engineering and cold distribution.

Cooling machine + control € 15,000 Collectors including assembly € 16,500 Buffer storage and distribution system € 9,000 Installation costs, accessory, recooling system inclusive piping

€ 5,500

Additional costs and detailed planning of the cooling

€ 9.000

Total € 55,000 8.2 Solar overcost evaluation Estimation of the overcost due to the solar system in comparison with a traditional system (for cooling and heating) A traditional cooling system can be installed at costs of € 10,000. The heat production of the solar system equals a conventional heating system which can be installed at costs of € 5.000. Thus, the overcost is about € 40,000. 8.3 Yearly energy savings evaluation Energy savings for different technologies (electricity, gas, fuel...) 3,250 kWh electrical energy; approx. 1,000 m3 natural gas 8.4 Subsidies

Level of subsidies available to support the project, final cost for the owner with deduction of the grants. Payback time. Preliminary economical calculations show negativ results. To obtain a better economical result the installation must be supported with subsidies. The owner of the plant will install the solar cooling system if the costs are equal or just a bit higher as a traditional system.

9. Environment benefit Estimation of the CO2 avoided emissions 5,841 kg / year

Annex 1 – Installation schemes Solar collector installation, technical premices, working priniciple

Annex 2 – Calculations Calculation data sheets, detailed results


Office building

Milano (Italy)


1.1 General presentation of the project Location: Milan (Italy) Headquarters of an association Total area of building to cool: 412 m2 Major functional areas of the building: - Multi-purpose rooms – 254 m3 heated and cooled with radiant panels; - Office – 1280 m3 heated and cooled with radiant panels and air treatment unit; - Cloakrooms – 72 m3 heated with radiators; - Total volume to cool: 1534 m3; - Total volume to heat: 1607 m3; Average floor height: 3,9 m 1.2 Existing cooling and heating equipment For the production of DHW and space heating 19 m2 of evacuated tube collectors are being used in addition to two 32 kW condenser boilers for the back-up system. The heating terminal for space heating are radiant panels. No cooling system is available. 1.3 Orientation of the study

Cooling season between May and end of September. Cooling peak demand 27 kW. Heating season between October and end of April: Heating peak demand: 26,6 kW. DHW production of 420 litres/day at 45 °C with an overall energy demand of 6 MWh/year. Solution proposed within specific constraints defined by the client: - to maintain the same surface area of solar panels; - to install absorption machine with chemical heat storage; - to use traditional chiller compressor; - to not use condenser boilers during summer season.


Office building organised on the basis of the open space concept with glazed partitions and an

enclosed meeting room. Inner height of ceilings 4,35 m and with a false ceiling placed at a height of 3,90 m realised with “eraclit” insulating boards. Above the floor slab there is a polystyrene layer where tubes for radiant heating have been placed below the pavement finish. Structure built in reinforced concrete frame and with perimeter walls in brick and concrete to which has been applied, during renovation works, an external insulating coat. Old industrial iron windows with single glazing replaced by double glazing low-emissivity 6/16/6 with air gap filled with gas. Characteristics of building elements: - perimeter walls: U-value 1,849 W/m2K and thickness 0,3 m; - roof: U-value 0,924 W/m2K and thickness 0,62 m; - floor slab: U-value 0,837 W/m2K and thickness 0,26 m; - windows: 5-12-5 U-value 2,191 W/m2K and thickness 0,022 m. 2.1 Occupancy Average occupancy rate: 0.07 people/m2 in moderate office activity (latent heat 38 W/m2, sensible heat 67 W/m2). Fluorescent lighting: 16 W/m2 Electrical appliances (e.g. 30computers, printers): Air change rate: 1,5 m3/hour

Multi-purpose hall: according to the programme Office running time: Monday to Saturday 2.2 Conclusions

We suggest the use of horizontal and vertical overhangs to minimise solar contribution and thus reduce cooling loads and improve internal comfort.


3.1 Building modelling with passive techniques (e.g. night ventilation) The building modelling (ASHRAE TFM) adopted does not allow us to take into account passive techniques, in particular night ventilation.


4.1 Sizing data

Energy - related comparison Unit Reference System

with Chiller Solar System

0. General Data

1 Collector type - Evacuated tube collector

Evacuated tube collector

2 Collector Area (absorber) m2 19 19

3 Volume of heat storage m3 0 0

4 Volume of Domestic Hot Water (DHW) lt 420 420

5 Airflow (air-handling unit) m3/h 1.000 1.000

6 Heating power, back-up heater (n.3 boiler) kW 32 32

7 Nominal chiller power, compression chiller kW 30 30

8 Nominal chiller power, thermally driven chiller kW 0,00 10

9 Nominal power of cooling tower kW 0,00 20

4.2 Solar absorption system sizing

Technical data of ClimateWell DB220 (see annex for more information)

Model DB220

Chiller Power kW 10

Input °C 12 Chilled Water Temperature

Output °C 7

Input °C 29 Cooling Water Temperature

Output °C -

Input °C 90

Output °C - Hot Water Temperature

Range °C 80 - 100

Electricity V/phase/Hz 220/1/50

Consumption W 40 - 80

Electrical current A 6 Electricity data

Consumption average kWh/year 580

Weight charge kg 112 Solution

Type LiCl

4.3 Solar collectors

Solar Collector data

Company Kloben

Model SP 16 CPC

Type Evacuated tube

a0 0,632

a1 0,936 a2 0,0076 Collector net surface 19 m2 Inclination of Collector 45 °

Azimuth south ° Average temperature of collector in summer 90 °C Average temperature of collector in winter 45 °C

4.4 Technical premises At the top floor level there is the availability of providing technical premises having a total surface area of: 60 m2.



5.2 Calculation results for solar cooling production, solar heating production and solar hot water production

Energy - related comparison Unit Reference

System with Chiller

Solar System

1. Result of annual energy balance for system design (obtained with simulation programme) 10 annual electricity consumption , chiller kWh 15.510,97 12.923,98

11 annual energy produced by solar collector for cooling/dehumidification

kWh 0,00 7.391,41

12 annual required heat for heating/humidification kWh 73.108,01 73.108,01 13 annual required heat for domestic hot water kWh 5.901,30 5.901,30 14 total annual heat kWh 79.009,31 86.400,72

15 annual heat from 2nd heat source low temperature (fossil fuel)

kWh 69.559,42 68.205,02

16 annual heat from 2nd heat source high temperature (fossil fuel)

kWh 0,00 0,00

17 total annual heat from 2nd heat source (fossil fuel) kWh 69.559,42 68.205,02 18 annual amount of fossil heat source (primary energy) kWh 67.533,42 66.218,47 19 annual radiation on collector kWh 32.329,64 32.329,64 20 annual heat produced by solar collector kWh 15.486,89 15.486,89 21 annual heat used by solar collector kWh 9.449,89 15.486,89 22 annual heat used by pre-heating DHW kWh 0,00 1.354,40 23 annual overall cold production (cooling, dehumidification) kWh 31.021,95 31.021,95 24 annual cold production by compression kWh 31.021,95 25.847,96 25 maximum electricity demand (maximum hourly value) kW 20,00 20,00 26 total annual water consumption m3 0,00 148,11

Energy - related comparison Unit Reference

System with Solar System

System with Chiller

2. Energy related evaluation 27 annual useful solar heat kWh 9.449,89 15.486,89 28 annual gross collector efficiency % 48 % 48% 39 annual net collector efficiency % 29 % 48% 30 annual COP of compression chiller - 2,00 2,00 31 annual COP of thermally driven cold production - - 0,70 32 annual primary energy consumption kWh 110.619,46 102.118,41 33 annual primary energy savings kWh - 8.501,04 34 relative primary energy savings % - 8 % 35 specific useful net collector output kWh/m2 497,36 815,10 36 specific primary energy saving kWh/m2 - 813,66

5.7 Conclusion Total solar energy produced and used in the building (7,4 MWh/year). Not being able to provide a larger solar collector surface area the absorption machine can only partially cover the required cooling load and the traditional chiller provides for the back-up. We suggest the installation of additional solar collectors on the facade of the building, positioned to act also as horizontal overhangs to screen from direct solar penetration the transparent surfaces.



See the annex 2. Red line: Delivery circuit. Blue Line: Return circuit.

7. Tele-monitoring

7.1 Tele-monitoring objectives

A tele-monitoring is not foreseen, but within the building there is an automatic thermal regulation of the entire plant.

8. Economical data


Economic Assessment Unit Reference System


1. Investment costs

37 solar collector system including supporting structure € 0,00 0,00

38 heat storage unit € 0,00 0,00

39 (additional) heat source (e.g. gas burner) € 0,00 0,00

40 Installation costs (including piping, pumps) € 2.000,00 6.000,00

41 air-heating unit or desiccant air-heating unit € 0,00 0,00

42 compression chiller € 8.134,20 8.134,20

43 thermally driven chiller € 0,00 10.000,00

44 cooling tower € 0,00 1.044,00

45 cold storage unit € 0,00 0,00

46 pumps € 0,00 0,00

47 control system € 1.000,00 1.000,00

48 planning costs € 500,00 720,00

49 total investment cost without funding subsidies € 11.634,20 26.898,20

50 funding (investment support) € 0,00 0,00

51 funding related to solar collector € 0,00 0,00

52 final total investment cost € 11.634,20 26.898,20

8.2 Yearly energy savings evaluation Energy savings for different technologies (electricity, gas, fuel...)



2. Annual costs

53 annuity factor, conventional equipment % 6,00 6,00

54 annuity factor, solar system (collector, storage) % - -

55 capital costs € 802,46 1.855,27

56 cost for maintenance, inspection € 232,68 300,00

57 annual electricity cost ( consumption) € 2.177,74 1.814,53

58 annual electricity cost (peak) € 1.200,00 1.200,00

59 annual heat cost (fossil fuel) € 1.918,82 1.881,46

60 annual w ater cost € 0,00 74,05

61 total annual cost € 6.331,70 7.125,32

62 annual extra cost of solar system € 0,00 793,61

63 annual operation an maintenance cost € 5.529,25 5.270,04

8.3 Subsidies



3. Comparative evaluation

64 payback time year 0 58,9 65 cost of saved primary energy €/kWhPE 0 0,093354697

Under the economical point of view, the payback period is too high versus its real benefits.

9. Environment benefit Estimation of the avoided CO2 emissions Economic Assessment Unit Solar System

66 saved electric energy kWh 2.586,99

67 CO2 saving due to electricity saving kg 1.482,58

68 saved electric power kW 0,00

69 saved fossil fuel energy for heat kWh 1.314,95

70 CO2 saving due to heat saving kg 272,53

71 water saving m3 -148,11

72 overall primary energy saving kWh 8.501,04

73 total CO2 saving kg 1.755,11

74 material pair solar system (refrigeration/sorbent) - water/LiCl 75 refrigerant reference system - FKW R134a

76 environment advantage of solar system - -



1.1 General presentation of the project Office building of a company Unterföhring / München (Germany)

- the building has a gross area of 66.000 m²; approximately 58.600 m² used area; - Office building with use from Monday to Friday, 08:00 am to 6:00 pm; - The building is very representative and architectural filed; - 640 employees are working in this building; - there is also a kitchen which is cooking 500 meals per day; - joined on the district heating system - it is the aim of the building owner to reduce CO2-emissions

1.2 Existing cooling and heating equipment As the building is used since 2001 the whole technology for cooling and heating is present: Energy Sources:

Unit Heating energy Capacity kW 2.500 Energy consumption for heating MWh/a 3.500 Electricity Capacity kW 1.280 Electric energy consumption MWh/a 5.700 Consumption of fresh water m³/a 17.500

Distribution System: 1. For heating and cooling: Ventilation system with heating and cooling exchangers (with 6 central

air conditioning systems) 2. For heating: floor heating system

3. For cooling: activation of constructional elements (cooled concrete-ceilings) Room temperature control system 1.3 Orientation of the study

It is a important aim of the building owner to reduce the CO2-emissions of the building. The building is getting its heating energy from a CHP-plant which is burning waste. Additionally to the innovative heating and cooling concept and to the heat-source the building management is always trying to reduce the energy consumption. There is a very high emphases to improve the building to a low energy consumption! The solar panels installed for the solar cooling will also produce heat in winter and in transition period for the hot water production of the building. There are 3 hot-water tanks with 500 liter volume each – so the support of the solar energy is interesting.


2.1 Building structure For the ventilation system there are 6 units which will be conditioned in a own central station. The central air conditioning is including in all units a heat recovery system. There is one central cooling-production with a cooling capacity of 1077 kW. The building has a high quote of glassed façade; there are two different sun protection devices in the building: first the outside rolling blinds which are controlled automatically, second the hedge around the whole building which has leaves in summer and is giving natural shading. The lightning concept is also very efficient. It is controlled via the central Building-control-System (with motion detector) and could be also switched manual. The lightning devices are very efficient (with reflector). The area on the flat roof is giving space for approx. 5.000 m² collector-area. 2.2 Occupancy In the building are working 640 employees. It is used from Monday to Friday, 08:00 am to 06:00 pm. 2.3 Conclusions

The building has the following specific energy consumption values: Energy source Unit SwissRe-Value Common value in

Germany

Specific Heating energy consumption

kWh/m²a 59,32 110

Specific electricity consumption kWh/m²a 96,61 18 Specific cooling energy consumption

kWh/m²a 8 50

As it is shown in the table above the building has a very good specific value concerning heating and cooling consumption. But in comparison to other office buildings in Germany the building has a very high specific electricity consumption. This results from the energy consumption of the ventilation system and from the high control standard. The cooling and heating distribution is based on a very good system. The cooling and heating of the surrounding faces in combination with the conditioned air system (air exchange rate of 1,2) is giving a very comfortable room climate and is producing the low heating and cooling consumption.


3.1 Building modelling for intial conditions 3.2 Building modelling with passive techniques (eg. night ventilation)


4.1 Sizing data

The building management has installed a amperemeter to measure the electricity consumption of the conventional cooling machines. We got the dates with 15 minutes measurement including the data about the temperature outside. With the given volts and with the given COP of the cooling machines we made the following graph showing the cooling load of the year 2004.

Jahresdauerlinie

0

100

200

300

400

500

600

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500

h/a

kW

Concerning this cooling loads of the building we decided to analyze a absorption cooling system. Why not the desiccant cooling system: because the later installation of a desiccant wheel in the air centrals is very difficult and expensive and the distribution of the hot air to each air-conditioning-central is very expensive and there are much heat losses. Why not the Adsorption machine: because this cooling machine is quite big and unfortunately very expensive. 4.2 Solar sorption system sizing

We decided to analyze two different sizes of absorption machines to get more information about the economy of smaller and bigger installation sites.

Absorption Chiller Unit Model 1 Model 2 Cooling capacity kW 100 200 Chilled water temperature °C 8/16 8/16 Hot water temperature °C 95 95 Electricity consumption W 500 1000 Working pair Water/LiBr Water/LiBr

4.3 Solar collectors

Evacuated tube collectors Unit Model 1 Model 2 Gross collector area m² 292 583 Net collector area m² 250 500 Optical Efficiency % 77,6 77,6 Annual efficiency % 55 58

4.4 Cooling tower (for ab or adsorption systems)

Wet cooling tower Unit Model 1 Model 2 Cooling capacity kW 250 510

4.5 Technical premises For the solar system it is also necessary to install a storage tank. The storage tank for the two models will have a volume of 9 and 18 m³. The storage tank as well as the cooling machine do have place on the roof and in the technical room in the ground floor. So it has to be decided where the technology has to be installed and which possibility has the most advantages.

To optimize the utilization of the absorption machine it is planned to use the district heating as a backup system. This should additionally reduce the electricity consumption and therefore the CO2-consumption (as the district heating is produced from burning waste).


5.1 Calculation methods 5.2 Meteorological data

Strahlungsdaten

020406080

100120140160180200220

1 2 3 4 5 6 7 8 9 10 11 12

Monate

kWh

/m²

Flä

che

The picture is giving the global radiation in Munich in one year. Reference: Deutscher Wetterdienst; 5.3 Calculation results for solar cooling production

Unit Conventional Model 1 Model 2 Global radiation of a year kWh/m²

a 1.178 1.178

Solar cooling energy kWh/a 0 84.100 177.500 Cooling energy from district heating

kWh/a 0 131.600 187.500

Electricity consumption for cooling

kWh/a 166.600 94.400 44.500

Annual COP conventional chiller

2,9 2,9 2,9

Annual COP absorption chiller 0,65 0,65 5.4 Calculation results for solar heating production

Unit Conventional Model 1 Model 2 Solar heating energy kWh/a 0 32.400 68.300 Consumption of district heating energy

KWh/a 3.500.000 3.467.600 3.431.700

5.7 Conclusion

Unit Conventional Model 1 Model 2 Reduction in electricity consumption

kWh/a 0 72.200 122.100

Primary energy factor for electricity

% 3,22 3,22 3,22

Annual primary energy savings kWh/a 0 232.400 393.000 Solar fraction for cooling % 16,9 35,6


6.1 Working principle There is a clear hierarchy between the use of the different energy sources to produce cooling energy: 1. absorption machine with solar energy 2. absorption machine with district heating 3. conventional cooling machine The storage tank should give the solar system the possibility to bridge over some hours if no sun is shining and no solar energy can be produced.

7. Telemonitoring

7.1 Telemonitoring objectives

The monitoring system should check the quality of the system and should give a clear overview of the energy balance. It is necessary to have a clear dates to improve the system continuous. 7.2 Measurment description

- Irradiation - Temperature outside - Power of absorption chiller - Power of evaporating and condensing energy - Electricity consumption of the secondary advices and absorption chiller - Electricity consumption of the conventional system - Temperature of the solar heating water - Temperature of the storage tank - Mass flow of the solar collector - Mass flow from the storage tank - Temperature of chilled water - Mass flow of chilled water - Temperature of the district heating system (secondary side)

- Mass flow of the district heating system to the absorption chiller - Mass flow and temperature of the cooling tower

8. Economical data


Unit Model 1 Model 2 Solar collector € 124.880 249.750 Storage tank € 13.500 27.000 Absorptions chiller € 50.000 90.000 Re-cooling tower € 8.750 17.850 Measuring system € 29.570 57.690 Installation costs € 23.660 38.460 Planning € 30.000 45.000 Total Investments € 280.360 525.750 8.2 Solar overcost evaluation / Yearly energy savings evaluation

Unit Conventional Model 1 Model 2 Capital costs €/a 0 15.890 29.310

Annual costs for electricity €/a 125.190 111.860 99.870

Annual costs for district heating (heating)

€/a 145.750 144.880 143.910

Annual costs for district heating (cooling)

€/a 0 3.550 6.060

Total annual costs €/a 270.940 272.590 273.090

Annual overcosts €/a 1.650 2.160

8.3 Subsidies

In the calculation to get the values from table 8.2 the support of the program Solarthermie2000plus has been integrated. It is possible to get 50 % of the collector costs, the planning costs and the measurement costs. For this project the subsidies values approx. 88.520 € for Model 1 and 171.090 € for Model 2.

9. Environnment benefit

Unit Model 1 Model 2 CO2-equivalent for electricity To/MWh 0,162 0,162

CO2-emission savings electricity Tons 12 20

CO2-equivalent for district heating To/MWh 0 0

Total CO2-savings € 12 20

The CO2-equivalent for electricity is lower than the equivalent of the typical “electricity-mix” in Germany because the SwissRe is sourcing electricity from hydropower (certificated ecological power).

Annex 1 – Installation schemes

Annex 2 – Calculations

Einheitkonventionelles

SystemVariante 1 Variante 2

Jährliche Sonneneinstrahlung kWh/m²a 0,00 1.178,00 1.178,00Netto-Kollektorfläche m² 0,00 250 500

spezifische nutzbare Sonnenenergie kWh/m²a 0,00 648 683Nutzbare Sonnenenergie kWh/a 0,00 161.813 341.279

Nutzbare Sonnenstrahlung für Kühlung kWh/a 0,00 129.450,55 273.022,98Nutzbare Sonnenstrahlung für Heizung kWh/a 0,00 32.362,64 68.255,74

Kälteenergiebedarf kWh/a 497.986,24 497.986,24 497.986,24davon solar erzeugt kWh/a 0,00 84.142,86 177.464,94

davon Absorption mit FW kWh/a 0,00 131.625,00 187.500,00

davon konventionell erzeugt kWh/a 497.986,24 282.218,38 133.021,30

Strombedarf zur Kälteerzeugung kWh/a 166.550,58 94.387,42 44.488,73

Wärmebedarf (inkl. Warmwasserbereitung) kWh/a 3.500.000,00 3.500.000,00 3.500.000,00Solare Heizungsunterstützung kWh/a 0,00 32.362,64 68.255,74

Benötigte Heizenergie (Fernwärme) kWh/a 3.500.000,00 3.467.637,36 3.431.744,26

Jährlich verwendete Solarenergie kWh/a 0,00 116.505,49 245.720,68

Jährlicher COP Kompression 2,99 2,99 2,99Jährlicher COP Absorption 0,00 0,65 0,65

EndenergiebedarfStrom kWh/a 166.550,58 94.387,42 44.488,73Fernwärme kWh/a 3.500.000,00 3.670.137,36 3.720.205,79

EndenergieeinsparungStrom kWh/a 0,00 72.163,16 122.061,85Fernwärme kWh/a 0,00 -170.137,36 -220.205,79

spez. Endenergieeinsparung für Kühlung kWh/m²a 0,00 288,94 244,37

Solarer Deckungsgrad Kälteerzeugung % 0,00 16,90 35,64

Reduktion der elektrischen Spitzen kW 0 100 200Elektr. Anschlussleistung kW 1280 1180 1080

Bewertung CO2 Strom to/MWh 0,647 0,647 0,647CO2-Einsparung to/a 0,00 46,69 78,97Bewertung CO2 Fernwärme to/MWh 0 0 0CO2-Einsparung to/a 0,00 0,00 0,00

Summe CO2-Einsparung to/a 0,00 46,69 78,97

Energetische und ökologische Betrachtung


System Variante 1 Variante 2

Spezifische PreiseSpezifische Kosten Vakuumkollektoranlage €/m² 0,00 500,00 500,00Spezifische Kosten Absorptionskältemasch. €/kW 0,00 500,00 450,00Spezifische Kosten Speicher €/m³ 0,00 1.500,00 1.500,00Spezifische Kosten Rückkühlwerk €/kW 0,00 35,00 35,00

InvestitionenKollektoranlage € 0,00 124.880,00 249.750,00Pufferspeicher € 0,00 13.500,00 27.000,00Absorptionskältemaschine € 0,00 50.000,00 90.000,00Kühlturm € 0,00 8.750,00 17.850,00Installation € 0,00 23.660,00 38.460,00Mess-, Steuer-, Regelsystem € 0,00 29.570,00 57.690,00

Planung, Entwicklung € 0,00 30.000,00 45.000,00

Investitionskosten € 0,00 280.360,00 525.750,00

Förderung Kollektoranlage € 0,00 49.952,00 99.900,00Förderung MSR € 0,00 29.570,00 57.690,00Förderung Planung € 0,00 9.000,00 13.500,00Förderung Absorptionskälteanlage € 0,00 0,00 0,00

Investitionskosten inkl. Förderung € 0,00 191.838,00 354.660,00

Investitionen

Wirtschaftlichkeit - Investitionen


SystemSolares System Solares System

A Wirtschaftliche PrämissenStrompreis Arbeit ct/kWh 6,00 6,00 6,00

Leistung €/kW 90,00 90,00 90,00Fernwärmepreis

Arbeit ct/kWh 2,70 2,70 2,70Leistung €/kW 20,50 20,50 20,50

Fremdkapitalzinssatz % 0,00 5,50 5,50Nutzungsdauer a 0,00 20,00 20,00Eigenkapital Zinssatz % 0,00 5,00 5,00

B InvestitionAnteil Eigenkapital 30% € 0,00 57.551,40 106.398,00Anteil Fremdkapital 70% € 0,00 134.286,60 248.262,00Summe € 0,00 191.838,00 354.660,00

C JahresgesamtkostenKapitalgebundene Kosten

Eigenkapital-Annuität € 0,00 4.618,07 8.537,65Fremdkapital-Annuität € 0,00 11.237,01 20.774,40Summe € 0,00 15.855,09 29.312,05

Verbrauchsgebundene KostenStrombezug € 125.193,03 111.863,25 99.869,32Fernwärme (Heizung) € 145.750,00 144.876,21 143.907,09Fernwärme (Kälte) € 0,00 3.553,88 5.062,50Summe € 270.943,03 256.739,45 243.776,42

Betriebsgebundene Kostenbleiben gleich

Kostensumme € 270.943,03 272.594,54 273.088,47

Mehrkosten pro Jahr € 0,00 1.651,50 2.145,43Kosten je eingesparte Tonne CO2 € 35,37 27,17

Wirtschaftlichkeit

Statische Investitionsrechnung SOLARE KLIMATISIERUNG



1.1 General presentation of the project Local Electric utility in Rhône Alpes area (Saint Etienne) Total area of the building to cool : 230 m², on 3 levels. Office building in 5 levels but only the 3 on the top are concerned Height per floor : 3 m. 1.2 Existing cooling and heating equipment No cooling equipment. 1.3 Orientation of the study

Cooling season between May and end of September. Cooling needs : 20 kW for the 3 levels. First priority for cooling : meeting room (77 m²). Heating in winter. No hot water needed. Space available for the technical premices in the attic – Only 80 m² on the roof for the collectors. -> Small solar absorption system (10 kW) chosen because no small size DEC available on the market.


2.1 Building structure Walls : stone 400 mm, internal insulation rockwool 85 mm, plaster 10 mm. Ceiling : concrete 100 mm, rockwool 100 mm, plaster 10 mm. Windows : double glazed 4/16/4 of U coefficient = 2,8 W/m².K No forced ventilation system Infiltration : 0,6 V/h Roof : tiles Division of the building into 3 separated zones (one per floor)

2.2 Occupancy - Level 3 (meeting room) : 20 à 30 people for 1 to 2 days/week. - Level 4 :3 rooms and 5 people. - Level 5 :3 rooms and 5 people. Planning : 8h->12h et 14h->18h from Monday to Friday 2.3 Conclusions

Solar protection to be added on the windows in the Southern facade 3. Impact of the improvement of the energetic quality of the building

3.1 Building modelling for intial conditions

External temperature >25°C Meeting room temperature >25°C Floor 4 temperature >25°C Floor 5 temperature >25°C 345 2858 3268 3191

Number of hours beyond the internal temperature limit (25°C) (between 01/05 and 30/09 (3 672 hours))

3.2 Building modelling with passive techniques (eg. night ventilation)

With solar protections : External temperature >25°C Meeting room temperature >25°C Floor 4 temperature >25°C Floor 5 temperature >25°C 345 1646 2385 2283

Number of hours beyond the internal temperature limit (25°C) (between 01/05 and 30/09 (3 672 hours))

Benefit of using solar protections but not sufficient : solar cooling required

10

15

20

25

30

35

40

45

50

5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8Mois

(°C

)

Salle Réunion R+4 R+5


4.1 Sizing data

Cooling load for the meeting room (instantaneous power in kW) 4.2 Solar sorption system sizing Phönix Absorption Chiller :

- Cooling power : 8,6 kW - Chilled water temp. : 6°C - Inlet generator temp. : 90°C - Inlet condensor temp. : 27°C - Evaporator flowrate : 2,9 m3/h - Generator flowrate : 1,2 m3/h - Absorber.condensor flowrate : 2,6 m3/h

4.3 Solar collectors 80 m² available on the roof. 15 Evacuated tube collectors (Cortec Giordano) Absorber area per unit : 1,675 m² Total useful area : 25 m²

0

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)

Charge thermique salle réunion (kW)

10

15

20

25

30

35

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45

50

5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8Mois

(°C

)

Salle Réunion R+4 R+5

Efficiency : • c0 = 0,836 • c1= 0,79 W/m².K. • c0= 0,009 W/m².K². 4.4 Cooling tower

Open cooling tower (but not definitive choice) Dimensions : 1,3 x 0,9 x 1,3 m (L x w x h) – Weight : nearly 120 kg. Features : - Cooling power :25 kW (10 kW + 15 kW), - Outlet temp. : 27°C, -Wet bulb temp. :22°C, - Flowrate : 2,6 m3/h. 4.5 Technical premices Located in the attic, just below the roof and on the top of the building. Dimensions : 3 x 2,5 x 2 m (L x w x h)


5.1 Calculation methods TRNSYS : hourly simulation for one year long of both the load (building) and the solar cooling system. 5.2 Meteorological data Average monthly meteo data from LYON (temperature and irradiation). Sinusoidal extrapolation made by TRNSYS 5.3 Components features Presence of a 500 liters hot water buffer storage between the solar collector field and the absorption machine. 5.4 Calculation results for solar cooling production

Cooling load for the meeting room (5 months of cooling season) : 3 535 kWh Solar cold production : 7 676 kWh (4 141 kWh available for the 2 other levels) Impact on the confort conditions of the meeting room (when empty and busy)

External temperature >25°C Meeting room temperature >25°C Busy meeting room temperature >25°C

Busy meeting room temperature >30°C

345 1034 159 11 Number of hours beyond the internal temperature limit (25 or 30°C)

(between 01/05 and 30/09 (3 672 hours)) 5.5 Calculation results for solar heating production Heating load for the 3 zones (7 months of heating season at 20°C) : 10 290 kWh Solar heat production : 11 026 kWh (but only 3 312 kWh in phase so usable to fit the load) 5.7 Calculation results for solar hot water production No hot water use.. 5.8 Conclusion

Total solar energy produced and used in the building : 10 990 kWh No need of a cooling back up system because the target is reached : acceptable confort conditions for the meeting room in summer. Heating back up in winter : central conventionnal heating system.



6.2 Working principle Priority to the meeting room when used. Cold production for the 2 other levels otherwise No interruption of the system during the week end (to maintain comfort conditions for the monday)

VE

RD

Circulateur

Clapet anti-retour(sens de circulation)

Vanne d'arrêt NO

Vanne d'arrêt NF

Soupape de sécurité

Cellule d'éclairement

Régulateur différentiel

Sonde

Purgeur d'air automatique

Compteur volumétrique àémetteur d'impulsions

Capteurs solaires

Eva Abs

Con

Gén

RD

Machine à absorption

Ventiloconvecteurs

80°C

29,5°C

Tour de refroidissement

VE

Ballontampon500 l

SIEL - Saint Etienne (26)


Principe général rafraîchissement etchauffage solaire

TECSOLBP 434 - TECNOSUD - 66 004 PERPIGNANTél : 04.68.68.16.40 Fax : 04.68.68.16.41

Juin 2004Schéma n° 3

7. Telemonitoring

7.1 Telemonitoring objectives To check the quality in the working of the installation, Capacity of a fast intervention in case of troubles.

7.2 Measurment description

Irradiance Solar collector loop energy Generator (or available for heatin) energy Evaporator energy Condensor energy State of the different pumps

8. Economical data

8.1 Project cost evaluation Technical premices Solar collector field + piping Primary loop Hot water buffer storage tank Absorption machine + generator loop Cooling tower + condensor loop Control + electricity Telemonitoring Engineering TOTAL Solar system cost : 44 800 € (without tax) Distribution network TOTAL cost estimation : 51 800 € (without tax)

8.2 Solar overcost evaluation

Gas configuration (indirect absorption chiller with a gas burner) : Cost of the absorption machine : 12 000 € Cost of the coolin tower + storage tank : 4 000 € Cost of the technical premices : 2 700 € Estimation of the overcost due to the solar system : 44 800 –12 000 –4 000 –2 700 =26 100 € Electricity configuration (reversible compression chiller) : Cost of the compression chiller : 3 000 € Cost of the technical premices : 2 700 € Estimation of the overcost due to the solar system : 44 800 – 3 000 – 2 700 = 39 100 €

8.3 Yearly energy savings evaluation

Gas (including conversion efficiencies) : Useful kWh in summer : 0.0638 €

Useful kWh in winter : 0,0407 € TOTAL savings : 624 €/year Electricity useful kWh (including conversion efficiencies) : 0,0452 € TOTAL savings : 497 €/year

8.4 Subsidies

Level of subsidies avalaibable to support the project : 70 % (but not yet fixed) Final cost for the owner with deduction of the grants : 13 440 € (distribution network excluded) Payback time : 21,5 years (gas) and 27 years (elec.)

9. Environnment benefit Estimation of the CO2 avoided emissions :

5,1 tons compared to gas 2,2 tons compared to electricity :

Annex 1 – Installation schemes

N

S

E

O

SIEL - St Etienne (42)


Implantation capteurs



Vue de dessus toiture bâtiment

Capteurs solairesContours toiture

4,8 m

17 m

Conduits cheminéesexistants

Trappe accès toiture

1,2 m

Canalisations

N

S

E

O

SIEL - St Etienne (42)Projet

Rafraîchissement solaireImplantation local technique



Contours toiture

Conduits cheminéesexistants

Ballon solaire

Machine absorption

Chappe béton

Arrivée canalisationssolaires

Réseaueau glacée

Vers tour derefroidissement

Régulation + circulateurs

Vue intérieur combles

A

A

Coupe A-A Trappe accès toitureMachine abs.

Ballon

Documents

Feasibility Study for Solar Cooling Systems