Energy Audit 2013

8/13/2019 Energy Audit 2013

1/82

Energy Audit

Prof. Gabriel Pita


2/82

Energy Management

Energy loss in any industrial process or plant is inevitable; it

Energy loss

Slide 2 of 53

.

But its economic and environmental impacts are not to be

taken lightly, thus explaining the growing need for industrial

energy efficiency.

Put simply, the level of energy efficiency a plant or process

can achieve is inversely proportionate to the energy loss

that occurs; the higher the loss, the lower the efficiency.


3/82

Energy Management

Where and how do most of the losses occur?How much energy is actually lost ?

Are they controllable or recoverable?

Energy loss

Slide 3 of 53

The answers to these questions remain well concealed in ablack box where once energy is input, we do not know what

really happens to it inside and how much the losses are.

It is only when we look into the black box and extract these

details that we are able to ascertain the performance of the

overall or process levels and respond more effectively to

the weaknesses in energy management.


4/82

Energy Management

Overall energy losses in a plant can result from losses due

to designs that do not incorporate energy efficient

specifications such as: heat recovery option

operations that run on inefficient methods

- -

Energy loss

Slide 4 of 53

programme

Reducing these losses will substantially increase the plant's

efficiency, but we need data to identify and quantify thelosses and subsequently suggest suitable techno-economic

solutions to minimize the losses. This data can be

acquired through energy audits.


5/82

Energy Management

Sankey Diagram as illustrative example forenergy chain efficiency.

Slide 5 of 53

Sankey Diagram as illustrative example for energy chain efficiency. Taken from GEA, 2012: Global EnergyAssessment Toward a Sustainable Future, Cambridge University Press, Cambridge UK and New York, NY, USAand the International Institute for Applied Systems Analysis, Laxenburg, Austria, p. 116


6/82

What is Energy Audit?

Energy Audit is a periodic examination of an

energy system to ensure that energy is

being used as efficient as possible.


7/82

Energy Management

Energy audit is a systematic study or survey toidentify how energy is being used in a building or

plant, and identifies energy savings opportunities.

Energy Audit

Slide 7 of 53

Using proper audit methods and equipment, an

energy audit provides the energy manager with

essential information on how much, where and how

energy is used within an organization (factory orbuilding).


8/82

Energy Management

This will indicate the performance at the overall plant or

process level.

The energy manager can compare these performances

against past and future levels for a proper energy

management.

Energy Audit

Slide 8 of 53

The main part of the energy audit report are energy

savings proposals comprising of technical and

economic analysis of projects.

Looking at the final output, an energy audit can also be

defined as a systematic search for energy conservation

opportunities.


9/82

Energy Management

The Sankey diagram shows the energy balance ofa house for a mid-winter week.

Slide 9 of 53

Flows are in kWh, total amount 804 kWh. Energy sources/types are from the left (purchased heat,domestic hot water, solar gains), energy consumption and losses to the right (heat loss throughwindows, ceilings, walls).


10/82

Energy Management

The auditing process should identifyenergy-management opportunitiesEMOs

In many situations major cost savings can be achievedthrough the implementation of no cost or low cost

measures, such as:

Changing energy tariff; Rescheduling production activities to take advantage of

referential tariffs

Slide 10 of 53

Adjusting existing controls so that plant operationmatches the actual requirements of the building ormanufacturing process;

Implementing good housekeeping policies, in which staffare encouraged to avoid energy-wasteful practices

Investing in small capital items such as thermostats andtime switches.

Some times it is necessary to undertake more capitalintense measures.


11/82

Energy Management

Energy audit can be categorized into two types:

namely walk-through or preliminary auditdetail audit.

Energy audit stages

Slide 11 of 53

Sankey diagram for energy gains and losses in abuilding.


12/82

Energy Management

Walk-through or preliminary audit comprises:

one day or half-day visit to a plant

Walk-through or preliminary audit

Slide 12 of 53

historical data provided during the visit.

The findings will be a general comment based on rule-

of-thumbs, energy best practices or the manufacturer'sdata. It seek to establish the quantity and cost of

each form of energy used in a facility


13/82

Energy Management

Quick overview of energy use patterns

Provides guidance for energy accounting system

Provides personnel with perspectives of processes and

equipment

Preliminary Energy audit

Slide 13 of 53

Identify energy intensive processes and equipment

Identify energy inefficiency ,if any

Set the stage for detailed energy survey


14/82

Energy Management

GUIDELINES FOR PRELIMINARY ENERGY AUDIT

REPORT

Introduction

Overview of current systems in place How much energy is being consumed;

Slide 14 of 53

a ype o energy s e ng consume

The performance of the facility compared with other similar facilities; The characteristic performance of the facility

Scope of work for energy audit

Recommendations and the associated

costs and savings

Conclusions


15/82

Energy Management

Detail audit is carried out for the energy savings

proposal recommended in walk-through or

preliminary audit.

It will provide detailed data on the energy inputs

Detail audit

Slide 15 of 53

,

technical solution options and economic analysisfor the factory management to decide project

implementation or priority. A feasibility study will

be required to determine the viability of each

option.


16/82

Energy Management

Detailed evaluation of energy use pattern

By processes and equipment

Measurement of energy use parameters

Detailed Energy Survey

Slide 16 of 53

Evaluation of efficiencies

Identify energy saving options and measures

Recommendation for implementation


17/82

Energy Management

Slide 17 of 53


18/82

Energy Management

Slide 18 of 53


19/82

Energy Management

Slide 19 of 53


20/82

Energy Management

Introduction

Methodology and instrumentation Detailed survey of the management and operation characteristics of a facility

The energy supply

The energy use within the facility

The plant and equipment within facility Data analysis and findings including graphs and plots.

Determine the energy performance of a facility.

Identify and quantify the principal energy flows

GUIDELINES FOR DETAILED ENERGYAUDIT REPORT

Slide 20 of 53

Identified and quantify achievable energy cost savings

Summary of recommendations and the associated costs and

savings

Conclusion

Appendices

CD containing raw measurement data collected during the audit, in

a readable file format


21/82

Energy Management

EQUIPMENT

Slide 21 of 53


22/82

Energy Management

Physical entities Electricity

Mass flow Temperature Humidity

Equipment Electrical analyzer

Anemometer (turbine, Pitot) Thermometer Humidity meter

Slide 22 of 53

ue gases compos on Luminance Total dissolved solids

, , ana yzer Luximeter TDS meter


23/82

Energy Management

Slide 23 of 53


24/82

Energy Management

Measuring air velocity - flow

Slide 24 of 53

E M t


25/82

Energy Management

Combustion Efficiency &

Environmental Analyzer

Slide 25 of 53

E M t


26/82

Energy Management

Thermographic image

Infrared Temperature Measurement

Slide 26 of 53

Energy Management


27/82

Energy Management

250

300

350

400

450

ia(kW)

Sbado6 feira5 feira4 feira

Slide 27 of 53

0

50

100

150

200

0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:

Po

tn

Potncia Mdia Potncia Instantnea

Energy Management


28/82

Energy Management

20

25

30

35

40

45

50

Potncia(kW)

Slide 28 of 53

0

5

10

15

12:00 15:00 18:00 21:00 0:00 3:00 6:00 9:00 12:00

P. Mdia P. Instantnea

Medies no compressor 793

Energy Management


29/82

Energy Management

Slide 29 of 53

Energy Management


30/82

Energy Management

Energy balances in energy audits

The energy balance in EAs differs from currentthermodinamic energy balances because some

Slide 30 of 53

.

Unknowns obtained from measurements have anerror of measurement

As a consequence, calculated unknowns do alsoshow errors.

Energy Management


31/82

gy g



Slide 31 of 53

.



Energy Management


32/82

gy g

Energy audit objectives:1 - Energy accountancy (data)

Slide 32 of 53

2 - Energy consumption (measurements)Direct measurement

Energy balance (equation +measures)

3 - Energy savings

Energy Management


33/82



Slide 33 of 53

.



Energy Management


34/82

Problems in energy balances

The number of equations frequentlydiffers from the number of unknowns

N. equations > N. unknows

Slide 34 of 53

measurement results in an equation)

Create a chance to validateequations

N. equations < N. Unknows

Requires estimatives

Energy Management


35/82

WallLosses

3

Example: Industrial heat generator

Slide 35 of 53

Electricalresistance

21

Qelec

Energy Management


36/82

Equations and unknowns:

Mass and energy balance:

LossHTCmQTCmTCmmmm

.332211

321

+=++=+

&

Slide 36 of 53

Unknowns - measurements:

Good confidence: Q, T1, T2, T3Less confidence: m1, m2

No confidence: m3, Heat loss

Energy Management


37/82

Case 1: Equilibrium

2 Equations = 2 Unknowns

Slide 37 of 53

easuremen s accep e :Q, T1, T2, T3, m1, m2

Unknowns obtained by 2 eq.

System:m3, Heat loss

Energy Management


38/82

Case 2: Less unknowns

2 Equations = 1 UnknownMeasurements accepted:

Slide 38 of 53

, , , , , ,

Unknown obtained by resolution:

Heat loss

Allows to create an error typeunknown:

Error of m3

Energy Management


39/82

Case 3: Less equations

2 Equations = 3 Unknowns

Measurements accepted:

Slide 39 of 53

Unknowns obtained by resolution:m2, m3, Loss

Requires more measurements (andmore equations, specific humidity):

Water balance:

Or assume a value for a unknown (!?)

332211 wmwmwm =+

Energy Management


40/82

Frontier definitionCharacterization of mass and energy

Energy balance sequence:

Slide 40 of 53

Equations identificationDefinition of measurement plan

Equipment selection

MeasurementsValidation

Energy Management


41/82

COMPRESSED AIR

Slide 41 of 53

Atlas Copco

Energy Management


42/82

=2

vdPw

Physics of compression

Slide 42 of 53

=

1

1

1

21

P

PTmC

W

p

Energy Management


43/82

Electrical measurements

150

200

250

ctrica[kW]

Funcionamento em carga Funcionamento em vazio

1

2

P

Slide 43 of 53

Example

0

50

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41

Tempo ([s]

Potnciael

t1 t2 t3

1Pp

Energy Management


44/82

Example 1: Boiler

Frontier anf flows

Slide 44 of 53

Combustionair

Natural gas

Flue gases

Water

Steam

Purge

Heat losses

CSC

Energy Management


45/82

DIRECT METHOD

( )hhmsteam waterfeedsteam=

Equations and measurements

Slide 45 of 53

Requires steam and combustible flow meters (feedwater meter is common)

mcomb

Required data

Energy Management


46/82

LOSSES METHOD (empiric)

=

Losses100%Boiler

Slide 46 of 53

=

1%)(Unburned

1%)(purgingSteam

3%)(Walls

steam

gasesry

10%)(gasesFlue

Losses

Energy Management


47/82

LOSSES BY THE WALLS

Where nominal losses depends on the boiler size, typically1,5%.

Functioning factor: by stack temperature

factorFuncioningL nominal-wallswalls

Lossesosses =

240

Slide 47 of 53

100

120

140

160

180

200

220

22-5-07 0:00 22-5-07 1:00 22-5-07 2:00 22-5-07 3:00 22-5-07 4:00 22-5-07 5:00 22-5-07 6:00 22-5-07 7:00

Temperatura[C]

Energy Management


48/82

Example 2: Aluminum furnace

Is known the following data:- Aluminum: flow and temp- Air: temperature- Combustion air: flow and tem

Slide 48 of 53

- Gases: temp, % O2

- Surfaces: temp, area- Fan: electrical power

Energy Management


49/82


Frontier and flows

Slide 49 of 53

Energy Management


50/82


Equations

Slide 50 of 53

++=+

=+

=

=++

gasesfluelossesheataluminumventilatorpropane

gasesflueinoxygenpropaneforoxygenairinoxygenaircombinoxygen

outaluminuminaluminum

gasesflueairpropaneaircomb

QQQWQ(4)

mmmm(3)

mm(2)

mmmm(1)

&&&&&

&&&&

&&

&&&&

Energy Management


51/82


Equations

=+

=

=++

gasesflueinoxygenpropaneforoxygenairinoxygenaircombinoxygen

outaluminuminaluminum

gasesflueairpropaneaircomb

mmmm(3)

mm(2)

mmmm(1)

&&&&

&&

&&&&

Slide 51 of 53

++=+

gasesfluelossesheataluminumventilatorpropaneQQQWQ(4) &&&&&

Energy Management


52/82

WATER AUDIT & CONSERVATION

Industry has recognized 'Water Audit' as a

important tool for water resource managementWater Audit study is a qualitative and quantitative

analysis of water consumption to identify means of

reuse and rec clin of water. This stud includes

Slide 52 of 53

segregation of effluent streams and schemes for

effectively treating them to enable byproductrecovery. Water Audits encourage social

responsibility by identifying wasteful use, enables

estimation of the saving potential they not only

promote water conservation but also deliver cost

savings, but also companies to safeguard public

health and property, improve external relations and

reduce legal liability.

Energy Management

preliminary energy audit of your home


53/82

p y gy y

Main processes involved in a preliminary audit

Collecting data

Slide 53 of 53

Presenting dataEstablishing priorities and making recommendations.

Energy Management

Collecting data


54/82

Collecting Building Information:

a)General building characteristics such as floor areas, numbers ofend-users, construction details, building orientation, building

facade, etc.;

b) Local Meteorological data

g

Slide 54 of 53

c) Check for air leaks, insulation,..

c)Technical characteristics of energy consumingequipment/systems;

d)Record of EMOs already implemented or to be implemented;

e)Energy consumption bills in previous three years.

Energy Management


55/82

Equipments:

Slide 55 of 53

Energy Management


56/82

Categora o tipo de artefacto y su potencia nominal en W

Potencia

nominal del

aparato

N de aparatosHoras utilizado

diariamente

Consumo en

kwh

Lmparas de bajo consumo y tubos

fluorescentes

9 W 0

11 W 0

15 W 0

20 W 0

Lmparas incandescentes

25 W 0

40 W 0

60 W 0

75 W 0

Calefactores de cuarzo, halgenas o

aire caliente

1600 W 0

1300 W 0

Slide 56 of 53

0

Lavarropas automtico alimentado conagua fra.

2000 W 00

Otros lavarropas350 W 0

0

Radiadores de aceite

1000 W 0

1500 W 0

0

0

Termos elctricos

1500 W 0

0

0

0

Energy Management


57/82

Televisores

90 W 0

125 W 0

0

0

Planchas

1500 W 0

1300 W 0

00

Cargador celular 13 W 0

Secador de pelo 1200 W 0

Equipo musical 150 W 0

Radio pequea 11 W 0

Slide 57 of 53

Microondas 1000 W 0

Batidora - Licuadora 600 W 0

0

0

Computador 50 W 0

Impresora 500 W 0

Scanner 300 W 0

Fax 120 W 0

Refrigeradores, freezer o

refrigeradores con freezer

170 W 0

250 W 0

0

0

Consumo Total Aproximado (Kwh) 0

Energy Management


58/82

Slide 58 of 53

Energy Management


59/82

ElectrodomsticoPotencia Elctrica

(Watts) Horas (da) Energa Wh (da)Energa kWh

(da)Energa Wh

(mes)

5 Bombillas de 75 W(Potencia total 75Wx5=375W)

75 4 1500 1,50 45,0

2 Bombillas de 60 W(Potencia total 60Wx2=120W)

60 1 120 0,12 3,60

Televisor de 21 140 5 700 0,70 21,0

Equipo de Sonido 200 1 200 0,20 6,0

Slide 59 of 53

Horno de Microondas 1200 0,50 (30 min) 600 0,60 18,0

Coffee Maker 800 0,50 (30 min) 400 0,40 12,0Olla Arrocera 700 0,50 (30 min) 350 0,35 10,5

Cocina discospequeos (2 discos)

1000 0,75 (45 min) 750 0,75 22,5

Cocina discosgrandes (4 discos)

18000,75 (45minutos)

1350 1,35 40.5

Refrigeradora 290 9 2610 2,61 78,3Termoducha 4000 0,50 2000 2,0 60,0Lavadora (10 das almes)

385 3 1155 1,15 11,6

Total Energa Elctrica (kWh) 329 kWh

Energy Management

Analyzing data


60/82

The most important source of energy data is the energy invoice.At lest one year of all energy invoices , electricity, gas, , should

be analyzed.

Any estimated meter readings should be identified, since this can

Slide 60 of 53

result in misleading data. To overcome this problems additional

invoices should be collected which cover the same months asthe estimated invoice, but for years prior to the audit period.

Energy Management

Electricity invoices:


61/82

Electricity invoices:

Slide 61 of 53

Energy Management


62/82

Muito Alta Tenso (MAT)Alta Tenso (AT)

Slide 62 of 53

Baixa Tenso (BT)Baixa Tenso Normal acima de 20,7kVA(BTN)Baixa Tenso Normal at 20,7kVA (BTN)

Energy Management


63/82

Slide 63 of 53

Energy Management


64/82

Slide 64 of 53

Energy Management


65/82

Consumo em quilowatt-hora (kWh): De modo a dar cumprimento s diretrizes europeias, os consumos de Gs

Natural passaram a ser faturados em unidade de energia - quilowatt-hora (kWh), em vez de unidade de volume -

metro cbico (m3).

Fator de converso de m3 para kWh: Para se obter o consumo faturado em kWh a partir de m3 de Gs Natural

necessrio aplicar um fator de converso que calculado a partir da seguinte frmula:

Fator de Converso (m3 para kWh) = PCS x Fct x Fcp

Em que:

PCS = Poder Calorfico Superior do Gs Natural. Valor correspondente mdia aritmtica dos valores de PCSmensal, relativos a todos os meses j concludos e englobados no perodo de faturao. Os valores de PCS mensal

so determinados pela mdia aritmtica dos valores de PCS dirio correspondentes.

Fct= Fator de correo por temperatura calculado pela frmula 273,15/(273,15+Tgs), em que Tgs corresponde

temperatura mdia, em C, da zona de distribuio.

Slide 65 of 53

, , ,

fornecimento em mbar.

Escales tarifrios

De acordo com o Regulamento tarifrio, a atualizao de preos efetuada anualmente, a cada ano gs (um ano gs

completo decorre de 1 de julho a 30 de junho do ano seguinte), para os clientes com consumo at 10.000 m3/ano.

Findo cada ano gs, a ERSE aprova os preos a vigorar para o ano gs seguinte.

Os clientes so enquadrados nos escales, tendo em considerao o seu histrico de consumo dos ltimos 12

meses,

Escales nacionais (m3/ano)

1 2 3 4

0-220 221-500 501-1.000 1.001-10.000

Energy Management


66/82

Tarifas de Venda a Clientes Finais em Baixa Presso < 10.000 m3/ ano

1. Este tarifrio est em vigor para o 2. Trimestre do ano gs 2013-2014 (01.10.2013 a

31.12.2013). O ano gs 2013-2014 corresponde ao perodo compreendido entre 01.07.2013 e

30.06.2014.

2. IVA aplicvel taxa de 23%.

3. Desde 1 de janeiro de 2013, o fornecimento de gs natural sujeito a um Imposto Especial

sobre o Consumo. Se utilizado como combustvel (fogo, esquentador, caldeira) o imposto de

0,001080 /kWh; se consumido como carburante de 0,010224 /kWh. A utilizao de gs

natural como carburante dever ser declarada pelo cliente.

Slide 66 of 53

EscaloConsumoanual (m3)

Termo tarifriofixo ( /dia)

Energia ( /kWh)

Escalo 1 0 - 220 0,0732 0,0755

Escalo 2 221 - 500 0,1170 0,0700

Escalo 3 501 - 1.000 0,1732 0,0658

Escalo 4 1.001 - 10.000 0,1819 0,0588

.

(www.erse.pt).

Energy Management

Household Energy Use: Where


67/82

Does the Money Go?

Slide 67 of 53

http://greenworldpics.com/2009/02/18/household-energy-use-where-does-the-money-go/

Energy Management

Format of Energy Audit Report


68/82

1Introduction

This part aims to describe the following topics:

a)The building audited - numbers of floors, floor areas, usage, occupancy, hours ofoperation, year built, etc., layouts and schematics to be attached as appendix;

b)Objectives, such as studying the building energy consumption with a view to

identifying EMOs for implementation, setting target savings, considering long term

Slide 68 of 53

energy management program, etc.;

c)Scope of audit, covering the installations to be studied such as HVAC Installation,Electrical Installation, Lift & Escalator systems, Plumbing & Drainage Systems or

any particular equipment/systems, the depth of the study, the parties involved (end-

user, building management, O&M personnel, etc.); and

d)Members of the audit team, and audit consultant employed, if any.

Energy Management


2 Description of Equipment/Systems Audited


69/82

This part aims to focus on the following issues:

a)Describe equipment/systems audited, their corresponding capacities and ratings,

design conditions, etc., equipment schedules, schematics and layout drawings to be

included as appendix.

b)Make use of information provided by the building management, O&M personneland end-users and site surveys.

c)State the design conditions if known, and if not known the conditions adopted as

base reference and calculations in the audit.

Slide 69 of 53

s ou nc u e e o ow ng con en s:-

a)Zoning of systems according to building height or usage ;

b)HVAC Installation for different areas type of system e.g. VAV, CAV, FCU, etc.;

types of controls; type and numbers of chillers, pumps, heat rejection methods, etc.

and their locations;

c)Lighting Installation type of lighting for different areas and type of control and

zoning;

d)Electrical Installation numbers of transformers and low voltage main switch-boards and their locations and size or ratings of main distribution cables/bus ducts;

e)Lift Installation and Escalator Installation capacity, zoning, quantity, floors/areas

served and types of control, types of drive;

f)Plumbing and Drainage System;

g)Hot Water System type of system; and

h)Other notable energy consuming equipment/systems.

Energy Management



70/82

3 Findings

This part aims to focus on description of the results of the site surveys and

should include:

a)Findings in a systematic format such as in order of systems(e.g. first on HVAC

Installation, then on Lighting Installation, etc.) or in order of floors (e.g. from

lowest level to top floor), or in order of usage (e.g. general office, private office,

Slide 70 of 53

, , .

b)Descriptions of floors/areas with special requirements (e.g.24-hour operation,

low space temperature for computer room, etc.);c)Calculation on cooling load, heating load, lighting load, electrical load and

annual energy consumption (detailed calculations should be included as

appendix);

d)Findings on O&M procedures and practices; and

e)Preliminary identification of possible EMOs against corresponding findings. Thedescriptions should focus on issues related to possible EMOs and provide

systematic numbering to findings for purpose of easy cross-reference.

Energy Management

4 - Analysis and Identification of Energy Management Opportunities



71/82

4 Analysis and Identification of Energy Management Opportunities

This part focuses on the detailed analysis and identification of EMOs and should

include:

a)Comparison on actual performances of equipment/systems against original design (if

information available) and/or actual site measurements for any discrepancies and

identify the causes thereof;

b)Possible EMOs and corresponding substantiations(calculations on achievable

energy savings and detailed descriptions as appendix);

Slide 71 of 53

numbers assigned to the findings detailed calculations, schematics and drawings

included as appendix);ENERGY AUDIT REPORTd)Comparison on the different solutions to the same EMOs ,as appropriate;

e)Classification of the EMOs into categories (Cat. I, Cat. II or Cat. III);

f)Listing of EMOs in a systematic format such as in order of system (e.g. first on HVAC

Installation, then on Lighting Installation, etc.) or in order of floors (e.g. from lowest

level to top floor) or in order of usage (e.g. general office, private office, commoncorridor, lift lobby, etc.);

g) Program for implementation of the EMOs;

h)Identification of areas for further study, if any;

i)Indication of parties concerned in the implementation of EMOs and the difficulties that

may encounter and general methodologies to overcome them; and

j)Initial investment and payback of each EMO in the summary.

Energy Management



72/82

5 - Recommendations

This part aims to focus on:

a) The initial investment and payback period of each EMO.

Slide 72 of 53

.

c) Grouping items of similar nature/location/usage together or group

according to their categories (Cat. I, Cat. II andCat. III).

Energy Management

Documents

Energy Audit 2013