ACMV Systems.pdf

7/17/2019 ACMV Systems.pdf

http://slidepdf.com/reader/full/acmv-systemspdf 1/171

Induction Course for new M&E Engineers

4 – 6 March 2013

Air Conditioning andMechanical Ventilation Systems



Mechanical Ventilation Systems

Induction Course for new M & E Engineers

Air-Conditioning and Mechanical Ventilation

6th March 2013

Ir. NG YONG KONG, P.Eng., GBIF, MASHRAEEmail: [email protected]

Tel: +6012 –

201 9319



1.ASHRAE Handbook – SI and Imperial Units

a.Fundamentals 2013

b.HVAC Systems and Equipment 2012

c.HVAC Applications 2011

d.Refrigeration 2010

2. Air Conditioning System Design - CARRIER3. Handbook of A/C Design – TRANE

4. CIBSE

5. MS 1525:2007 COP on Energy Efficiency and Use ofRenewable Energy for Non-Residential Buildings ( 1st Revision)

5. Uniform Building By – Laws 1984 (UBBL)

6. Guide to Fire Protection in Malaysia



INDUCTION COURSE IN

AIR-CONDITIONING1) INTRODUCTION TO AIR-CONDITIONING

2) PRINCIPLES OF REFRIGERATION

3) PSYCHROMETRICS

4) COOLING LOAD ESTIMATION & SOFTWARE5) REFRIGERANT ISSUE

6) TYPES OF AIR CONDITIONING SYSTEMS

7) AHRI 550/590 or MS2449 FOR CHILLERS

8) MS1525:20079) Green Building Index ( GBI )



1.) Introduction to Air Conditioning

What is Comfort?

Definition:

A State of Ease and Contentment”

• “A satisfying and enjoyable experience”

The feeling of comfort is clearly subjective.

Main components that determine comfort :

• Climatic conditions• Outdoor environment

• Indoor environment

• Activities & clothing



Comfort Requirements

• Temperature

• Humidity

• Air movement

• Fresh air

• Clean air

• Noise level

• Lighting

• Furniture and work surfaces



ASHRAE Comfort Zone



ASHRAE Standard 55-2010

Specifiesconditions likelyto be thermally

acceptable to atleast 80% of theadult occupants

in a space





Specifies Conditions likely to be thermally acceptable to at least 80%of the adult occupants in a space

Design to ASHRAE 55-2010 : Thermal EnvironmentalConditions for Human Occupancy in conjunction relevantlocalised parameters as listed in MS 1525:2007

6 Primary factors that must be addressed whendefining conditions for thermal comfort are:

1.) Metabolic rate2.) Clothing insulation3.) Air temperature

4.) Radiant temperature5.) Air speed6.) Humidity



2. What is a Refrigerant?A refrigerant is a fluid that absorbs heat and changes fromvapor to liquid phase at reasonable pressures and temperaturesas encountered in mechanical refrigeration.

Princ iples of Refr igeration

• The science of refrigeration is based upon the fact that a liquid canbe vaporised at any desired temperature by changing the pressure

on it.• Liquids boiling at low temperatures (Refrigerants) are the most

desirable medium for removing heat.• The large quantities of heat is absorbed when liquid is evaporated

(Changed to vapour).



2.What is a Refrigerant.

PRESSURE psia

F Water HCFC-22 HFC-410A HFC-134a CO2 Propane

-40 0.00186 15.26 26 7.43 145.77 16.1

0 0.0185 38.73 64 21.62 305.80 38.4

40 0.122 82.28 132 49.70 567.50 78.6

100 0.950 210.70 340 138.80 X 188.6

130 2.225 311.60 500 213.40 X 273.3

212 14.696 *CP *CP 587.20 X X

*Critical Point, pressure psia



Four Laws of System Operation

1. Heat only moves from a higher temperatureto a lower temperature

2. A large amount of energy is required to

change the state of matter

3. The temperature and energy required tochange state are a function of pressure

4. Fluid flow only occurs if a pressuredifference exists



Three Types of Heat Transfer

Conduction – Transfer by contact

Convection – May be natural or forcedtransfer by density currents and fluid motion

Radiation – Transfer by electromagnetic waves

Mechanical refrigeration uses the first two.

Convection

Conduction



Sensible Heat

1 FRISE

Btu is the heat energy necessary tochange one pound of water by 1° F

1 lb

1 Btu

Btu – British thermal unit

1 ton = 12,000 Btu/Hr.= 3.517 kWr



Latent HeatTotal Heat = Sensible Heat + Latent Heat

Change of State

212° F

212° F

Section 2 – Basic Principles

Not measured ona thermometer



Refrigeration Cycle• The refrigeration can be obtained by use of

the refrigerants.

• When the liquid refrigerants are allowed toexpose to the atmosphere, it evaporates andrefrigeration can be obtained.

• To make use of the vaporised refrigerantover and over again it is necessary to usethe devices like evaporator, compressor andcondenser.



Four Components Are Required

4. Pressure/flow control

valve

2. Vaporpump

1. Heat absorbing section

3. Heat rejecting section





Basic System Components

Evaporator

55°

F90.8 psia

Rejects the heat from the loadand system losses

Highly superheated refrigerant

condenses in the tubes as heat load isrejected and changes back to aliquid and is subcooled

SET

SST

SDTSCT

Every system has four

basic components

Evaporator

Compressor

Condenser

45° F90.8 psia

108°

F274.7 psia

Air in: 80° F db / 67° F wb

Air out: 59.7° F db / 57.3° F wb

Compressor

Air in: 95° F

Air out: 115° F dbCondenser

120°

F274.7 psia



3. Psychrometrics



Objectives• Understand the properties of air and water

vapor mixtures

• Build the psychrometric chart

• Use the psychrometric chart to determine

the properties of an air/water vapor mixture

• Use the psychrometric chart to understandthe basic air conditioning processes

• Understand how the processes can becombined into a system using a system plotdiagram and psychrometric chart

Section 1 – Introduction



Why Study Psychrometrics?


1. Determine the temperatureat which condensation will

occur in walls or on a duct

2. Find all the properties of airby knowing two conditions

3. Calculate the required airflow to

the space and for the equipment4. Determine the sensible and total

cooling load the unit shouldprovide

5. Determine the coil depth andtemperature to meet the designload conditions

Brooklyn Printing Plant



Dry-Bulb Thermometer

The temperature of air as measured by athermometer with a dry sensing bulb



Wet-Bulb Thermometer

The temp. at which water will evaporate into the airsample.

Physically…the temp. of air when measured by athermometer with a wetted wick over the sensing bulb.



Section 3 – Building the Psychrometric Chart

Sling Psychrometer

• Avoid adverse conditions that can affect reading

• Moisten wick before procedure

• Rotate device at least 2 minutes

• Read device immediately after rotation



Water Vapor in Air

Mechanical Mixture

Dry Air WaterVapor

Air + Vapor



50% 100% (saturated)

Relative Humidity ( RH )

If RH of the air is 50%, it contains one-half the amount of moisturepossible at the existing dry-bulb temperature.



Relative Humidity

RelativeHumidity

Amount of moisture that a given

amount of air is holding=

Amount of moisture that a given

amount of air can holdAt the same dry-bulb temperature.

The amount of water vapour in the air, compared to it’s maximumcapacity at that dry bulb temperature.

D B lb T t S l



Dry Bulb Temperature Scale

wb dp°F

db°F

Section 3 – Building the Psychrometric Chart



Dew Point Example

55° 67°

95° F

db100 gr

95°

100 gr

wb dp°F

db°F



Condensation Occurs atDew Point

Air Conditioning Clinic TRG-TRC001-EN © American Standard Inc. 1999



Relative Humidity Lines

Relative

Humidity Approx.

%4513260

132 gr

45%

75°

60 gr

wb dp°F

db°F

E th l S l



Enthalpy Scale

hs = 27.5 Btu/lb

wb dp°F

db°F

hs = Enthalpy at saturation



Psychrometric Chart

Dew PointTemperature

Dry BulbTemperature

Wet Bulb Temperature

SpecificHumidity

RelativeHumidity

wb dp°F

db°F

SpecificVolume

Enthalpy

Ai C diti i P



Air Conditioning Processes1. Sensible Heating

2. Sensible Cooling

3. Humidification4. Dehumidification

5. Cooling and Humidification(Evaporative Cooling)

6. Cooling andDehumidification

7. Heating andHumidification

8. Heating andDehumidification

wb dp°F

db°F



Sensible Heat

Sensible Heat Change

68% rh

HEATING

90 – 60 = 30

52 gr

t

90° 60°

db - Changeswb - Changesdp - Constantgr - Constant

tcfm10.1qs

COOLING

24% rh

wb dp°F

db°F



Latent Heat

75°

30 gr

89 gr

grainscfmq l 69.0

LatentHeat

Change

68% rh24% rh

89 – 30 = 60

grains

C on d en s a t i on

E v a p or a t i on

wb - Changesdp - Changesgr - Changesdb - Constant

wb dp°F

db°F



Total Heat

G r a i n s

95°

t

lst qqq

Sensible Heat Change 75°

Cooling

Heating

C o n d e n s a t i o n

E v a p or a t i on

30 gr

89 gr

wb dp°F

db°F

LatentHeat

Change



Using Enthalpy to Determine Total HeatRemoved

Latent Heat

Sensible Heat

55° 75°

wb dp°F

db°F

1.7

5.0



Total Capacity or Load Formula

GTH = 4.5 cfm hWhere:

GTH = Grand Total Heat4.5 = Constant

cfm = cubic feet per minute

h = Difference in enthalpy fromair entering to air leavingconditions

Cooling Coils



Cooling Coils

HeightLength

Face Area = Length Height

Velocity

Fins

Rows

cfm / face area

RefrigerantTemperature



ASHRAE Comfort Zone



4.) Cooling Load Estimation

To design the effective HVAC design, the analysis of heat

load is carried out.

Cooling Load Components:

- Location/altitude/ orientation

• Transmission through Building Components -

walls, glass, ceilings, roofs, doors and floors,

partitions from non conditioned spaces.

• Solar Radiations on - glass, wall, roof, etc.



Human Comfort - Design

•

Ventilation Requirements.

• Latent and Sensible heat losses from people.

• Lighting and ballasts.

• Appliances and equipment in the conditioned space.

• Ducts and motor heat gain from cooling system itself.

• Infiltration of outdoor air.







Building code requirements

Extract from Third Schedule (By-law 41)



ASHRAE STD 62.1-2010 Ventilation For AcceptableFor Indoor Air Quality

Ventilation is the key toSustainable IAQ and

ASHRAE Std 62.1 is theLeading Standardadopted by most Local

Authorities and HVAC

Engineers in the world.



1.) Ventilation Rate Procedure ( VRP ) –

is a prescriptive procedure with a table of minimum required outdoor airflowrates per occupant for a variety of non-

residential occupancies.

The airflow rate per square foot of building floor area is based-on the design occupancy density and the required flow rate per person,

adjusted to reflect the air distribution system used.

Acceptable Indoor Air Quality is defined as air in which there areno known Contaminants at harmful Concentrations as determined

by Cognizant Authorities and with which a substantial majority( 80% or more ) of the people exposed do not expressdissatisfaction.

ASHRAE Std 62 1 2007 Ventilation For Acceptable Indoor Air Quality



1.) Ventilation Rate Procedure ( VRP )

Vbz = Rp.Pz + Ra.Az

Where Vbz = Design outdoor airflow required in thebreathing zone of the occupied space or spaces in azone,i.e the breathing zone outdoor air flow

Az = Zone floor area: the net occupiable floor area of the zonem2 ( ft2)

Pz = zone population: the largest number of people expectedto occupy the zone during typical usage.

Rp = outdoor airflow rate required per person as determinedfrom Table 6-1

Ra = outdoor airflow rate required per unit area as determinedfrom Table 6-1

ASHRAE Std 62.1-2007 – Ventilation For Acceptable Indoor Air Quality

ASHRAE Std 62.1-2010 – Ventilation For



1.) Ventilation Rate Procedure ( VRP )

2.) Indoor Air Quality Procedure ( IAQ )

- air filtration/purification to remove some or all of the

contaminants of concern can be part of the system.

Acceptable Indoor Air Quality



TABLE 6-1 MINIMUM VENTILATION RATES INBREATHING ZONE

People Outdoor Area Outdoor Default Values

Occupancy Air Rate Air Rate

Occupant

Density

Combined

Outdoor

Category R p Ra

Air Rate

cfm/

person

L/s

person

cfm/ft

² L/s

m²

#1000 ft² cfm/

person

L/s

personor #100 m²

Office

Buildings

Office

Space 5 2.5 0.06 0.3 5 17 8.5

Reception

areas 5 2.5 0.06 0.3 30 7 3.5



Hotels, Motels, Resort,

Dormitories

Bedroom / living

room 5 2.5 0.06 0.3 10 11 5.5

Barracks sleepingareas 5 2.5 0.06 0.3 20 8 4.0

Laundry rooms,

central 5 2.5 0.12 0.6 10 17 8.5

Laundry rooms within 5 2.5 0.12 0.6 10 17 8.5dwelling units

Lobbies / pre-function 7.5 3.8 0.06 0.3 30 10 4.8

Multipurpose assembly 5 2.5 0.06 0.3 120 6 2.8

TABLE 6-1 MINIMUM VENTILATION RATES IN BREATHING ZONE



MS1525-2007

Air Conditioning and Mechanical Ventilation (ACMV) System

Indoor Design Condition

a) Recommended Design DB Temperature 23 - 26ºC (73.4 – 78.8°F )

b) Minimum DB Temperature 22ºC

c) Recommended Design RH 55% - 70%

d) Recommended Air Movement 0.15 m/s – 0.50m/s

e) Maximum Air Movement 0.7 m/s

Outdoor Design Conditions

a) Recommended Outdoor Design 33.3ºC / 27.2ºC

Conditions DB / WB ( 92°F/ 81°F )



ASHRAE Comfort Zone



Type of Refrigerants

CFC

•R-11•R-12•R-13•R-500•R-502•R-503

HCFC

•R-22•R-123•R-401A•R-401B•R-402A•R-402B•

R-408A•R-409A

HFC

•R-134a•R404A•R-407C•R-410A•R-507

HFO

HFO1234fy

5 ) Refrigerant Issue



5.) Refrigerant Issue-Environmental Impact

• ODP: Ozone Depletion Potential

• GWP: Global Warming Potential

• Climate Change

7 ) TYPES OF AIR CONDITIONING



7.) TYPES OF AIR CONDITIONINGSYSTEMS

• WRACs are factory-made assemblies that normally

include an evaporator or cooling coil and acompressor-condenser combination

• Room Air Conditioners are encased assemblies

designed primarily for mounting in a window orthrough a wall and are often called Window Room

Air Conditioners ( WRAC ).

WRAC



Window Room Air Conditioner

Window room air conditioner







Air Cool Split Units

• A Unitary Air Conditioner with more than onefactory-made assembly is commonly called a splitsystem.

• It basically comprises an indoor unit with theevaporator and blower and an outdoor unit withthe compressor, condenser coil and fan coupledwith refrigeration piping.

• The indoor units is often known as Fan Coil Units( FCUs )and the outdoor units known asCondensing Units. As a whole, they are known asthe Air Cooled Split Units. (ACSUs)

3 Ai C l d S lit U it



3. Air Cooled Split UnitsWarm air (recirculating)

Cool air

Outdoor air

Fan Coil Unit

Condensing Unit

3 Air Cooled Split Units (ACSUs)



3.Air Cooled Split Units (ACSUs)

Both indoor and outdoor units are housed in

robust casings. The outdoor unit is basicallythe same construction for all the various typesof indoor units. The difference lies in the type

of indoor unit.Wall Mounted Cassette

Ceiling Exposed

Floor Standing

3 Ai C l d S lit U it



3. Air Cooled Split Units

Type Typical CoolingCapacity (kWr)

Remark

Wall mounted 2.64-7.03 Most common

Ceiling cassette 5.26-14.65 Most aesthetic

Floor Standing 7.03-14.65 Not so Common

here

Under Ceiling

Exposed

5.26-17.60 Can be Floor

mounted

Common Fan Coil Units



3. Air Cooled Split Units

The installation of an Air Cooled Split Unit isbasically the same with the outdoor and indoorunits connected with refrigerating piping calledSuction and Liquid line.

Manufacturers recommend a Maximum Pipinglength of 7 to 15 m and maximum elevationbetween indoor and outdoor unit of 5 to 7 m.



4b.) Air Cooled Split Units

Many Business Establishments are housedin Small Premises using ACSUs.

Office Restaurant



Shop Office

4b.) ACSUs Application



Advantages

• Low first cost• Flexibilities

• Easy to maintain

• Short lead time• Ex Stock

Other Systems

• Low Efficiency

• No Fresh Air

• Potential IAQ

issues



3. ACSUs : Fresh Air Intake ?

The wall mountedand under ceilingsplit system has noprovision for intake

of outdoor air and/orexhaust of staleroom air.

Room air is justfiltered and re-circulated.

.

3 ) Air Cooled Split Units



3.) Air Cooled Split Units

The Ceiling Cassette Split

System has a knockout in thecasing that allows outdoorfresh air to be introduced.

A fan may be

added if theintake is faraway.



5. Water-cooled Splits/Packaged Units

-

WC Splits- Typ. Capacity range

from 2.0 – 6 Hp

- Ducted/Under

ceiling

- WC Packaged

- Typ. Capacity range

from 20 –

100 Hp- Floor Standing

Typical kw / ton around 1.0- 1.2 kw/ton



On a single refrigerant pipe, manyindoor units can be connected.

6. Variable Refrigerant System



Advantages

• Flexibilities

• Better RH than ACSUs

• Space Saving

• Better EE than ACSUs

Others Systems

• Moderate EnergyEfficiencyCompared to

CHWS

• Potential IAQProblem



Chilled Water System

coolingtower

condenser

97°F (36.1

C)

87

F (30.6

C)

110°F (43.3

C)

41°F (5.0

C)

50°F (10

C)

44°F (6.7

C)

54°F (12.2

C)

55°F (12.8

C)

80°F (26.7

C)

100°F (37.8

C)

controlvalve

pump

Condenser Water Loop(CWP, Piping & Cooling Tower)

Chilled Water Loop(CHWP, Piping &Cooling Coil)

Refrigeration Loop(Water-cooled Chiller)

Airside Loop(AHU & Air Duct)



Packaged Air-Cooled Chiller

compressor

evaporator air-cooledcondenser

expansiondevice

Refrigeration Loop(Air-cooled Chiller)

Chilled Water Loop(CHWP, Piping &Cooling Coil)

Airside Loop(AHU & Air Duct)



Conventional chilled water system

54°F

[12.2

C]

44°F

[6.7

C]

3-way valve



Primary-Secondary Configuration

primarypumps

two-way valve

Variablesecondarypump

distributionloop

productionloop



Variable-Primary-Flow Systems

two-wayvalve

Variable-flowpumps

control

valve

checkvalves

optional bypasswith three-way valve



Constant Primary Flow / Variable SecondaryFlow Chilled Water System

Chiller (Constant

Flow)

Chiller (Constant

Flow) Load(Variable

Flow)

Load(Variable

Flow)

D e c o u p l i n g B y p a s s

Primary Pumps

(Constant Speed)

Secondary Pumps(Variable Speed)

P

Isolation

Valves

Control

Valves

80

Type of Chiller Compressors



ScrollReciprocating

Helical-RotaryScrew Centrifugal

Compressor

Type of Chiller Compressors(Hermetic or Semi-Hermetic)



Air-cooled Chiller

Scroll & Screw & some using Reciprocating

• 20 – 100RT for Scroll

• 70 – 500 RT for Screw

• Typical Efficiencyrange 1.1 – 1.3 kw/ton

• Applications :

• Retail, Commercial,Industrial & Government



Water-cooled Chiller

Scroll & Screw & some using Reciprocating

• 20 – 100RT for Scroll

• 70 – 400RT for Screw

• 100 – 2500 RT

• Typical Efficiency

range 0.5 – 0.7 kw/ton

• Applications :

• Retail, Commercial,Industrial & Govt.

Buildings



• Avoid VSD Chillers - Centrifugal

Malaysian tropical climate has a near constant wet bulb temp thus VSDs do

not save a huge amount of energy. In temperate climates, the WB dropssignificantly, thus the condenser water supply will also drop- at low CWS,

the chiller compressors will overspeed

During low wetbulb temperature the lift changes, thus causing the compressorto overspeed, which is similar to a car moving downhill. The new “lift” for therefrigerant is achieved by reducing the compressor speed- thus, therefrigerant will work more effectively during those periods of low wet bulb

temperature.

Source: Malaysian Industrial Energy Audit Guidelines – MIEEIP, PTM

Variable Speed Chillers – Screw or



Centrifugal

Good variable Part Load Valuefor 4-season areas.

Low Ambient

Need to carefully Evaluate

Benefits.



DX versus Chilled Water

Major factors Affecting the Decision

• Installed Cost

• Energy Consumption

• Type of Application

• Space Requirements

• Building Aesthetics

• System Capacity

• Centralized Maintenance

• Stability of Control

• Redundancy

Air-Cooled vs Water-Cooled



Air Cooled vs Water Cooled

Air-cooled Water-cooled

Life Span 15 - 20 years 20 - 30 years

System EE kW/ton 1.0 - 1.3 0.9 - 1.1

Maintenance Lower Higher

Noise Containment Open Enclosed

Space Requirement Less More

Cost Lower Higher

Capacity Range 3 - 500RT 50 - 2,500RT+



Typical Energy Usage in a Commercial Building inHot/Humid climates

Other

Equipment

15%

AHU/FCU

24%

DHW

12%

Lighting

10%

Central

Plant

39%

Approx. 60% - AirConditioning Plant

Variable FrequencyDrive (VFD)/

Variable Speed Drive(VSD)/ SpeedController

-Improve comfort levels

-Reduce operating costs,

Chill d W t S t Di t R



Chilled Water System: Direct or ReverseReturn

DBCV - DYNAMIC BALANCING CONTROLVALVE



VALVEPICV – PRES. INDEPENDENT CONTROL

VALVE

Design• Pressure Independent

Control

• Automatic balancing• Commissioning

Save installation space & timeSave commissioning time &balancingEliminate error



Illuminated enclosure

GREEN: normal

RED: fault

Air Distribution System



Methods of Air Flow Control

Air flow :•Outlet dampers•Inlet guide vanes•Variable pitch fan•Variable Speed Drive(VSD/VFD)

Water Distribution System



Methods of Water Flow Control

Water Flow Centrifugal pumps :•Bypass valve (three way)•Throttling valve (two way)•Trim Impeller (irreversible)•Variable Speed Drive (VSD)

Fans and Centrif gal P mps F ndamentals



Fans and Centrifugal Pumps Fundamentals Affinity Laws

Air Flow2 Fan Speed2 Air Flow1 Fan Speed1

– Air/Water flow is proportional to Fan/Pump Speed

Static Pressure2 Air Flow2 Static Pressure1 Air Flow1

– Static Pressure is proportional to (Fan/PumpSpeed)2

Input Power 2 Air Flow2

Input Power 1 Air Flow1 – Input Power is proportional to (Fan/Pump Speed)3

w/o system effect

=

=

=

3

2

e.g

80% speed

Input power

= (0.8x0.8x0.8)

= 0.51 or 51%



•There are two types of air

distribution systems

i.)CAV - Constant Air Volumeii.)VAV – Variable Air Volume

Air Distribution System – Supply Fan Basics



CAV – Constant Air Volume• In CAV systems, thermal comfort is

achieved by delivering a constant volume of

supply air.• If location being served requires less

cooling, the supply air temperature remain

the same but the total volume of supply airremains the same as if full cooling isrequired




VFD/VSD Application - Supply Fan Basics

• There are two types of airdistribution systems

– Variable Air Volume

– Constant Air Volume

Supply Fan

• VFDs/VSDs are not only

applied to VAV systems

but can also be incorporated

into CAV systems.




CAV Supply Fan Basics

• No method of controlling air flowis provided

• The conditioned space receives“Design” air flow at all times

• The chilled water valves are

controlled by space temperature

Conditioned

Space

Supply

Fan

T

Sensor may be inreturn air duct.

• However, for large single zone CAVsystems, it’s possible to convert them

to single zone VAV systems



VAV – Variable Air Volume• To maintain thermally comfortable conditions,

VAV systems utilize a resetable constant

temperature of the delivered air to mostlocations, while varying the quantity of airdelivered to the individual zones in the building.

• Varying the air flow is controlled by using aVFD/VSD in the fan motor.



VAV - Variable Air Volume

SystemComponents:

1. VAV Box

2. Zone Thermostat

3. Air Diffuser

4. Return Grille

5. Duct Static Pressure

Sensor

6. Supply Fan VFD

7. AHU

8. Supply Duct

Zone 1 Zone 2 Zone 3 Zone 4





Why put a VFD/VSD on CAV SYSTEM

• Oversized systems

Variable Occupancy Profile

• Eliminate over capacity=> energy saving,

=> Lower Acoustic Noise

=> easier balancing

Better temperature control -maintain minimum airflow

- Vary from 70-100%

E.g :Hotel Lobby, Office or LiftLobby, Cineplex, Large Single

Zone office, conference hall,etc..




CAV to — Single Zone VAV using VFD/VSD

ConditionedSpace

Supply Fan Drive

Supply

Fan

T

T

Sensor may be in

return air duct.

• VFD controls air flow just as

VAV boxes would• Coils control supply air

temperature

• Works for large, single-zonesystems

Maintain minimum airflowtypically 70% and vary between70-100% based on temp, Airquality or CO2 inputs

Input Power2 Air Flow2 3 Input Power1 Air Flow1 eg 80% Input Power = (0.8 x 0.8 x 0.8)

Input Power is proportional to (Fan Speed) = 0.51 or 51% – w/o system effect

=

Chiller Standard Performance Rating



Chiller Standard Performance RatingStandard

( Air-Conditioning, Heating

and Refrigeration Institute)

AHRI STD. 551/591 – 2011



MS 1525:2007

Code of Practice on

Energy Efficiency and

Use of RenewableEnergy for Non-

Residential Buildings

(1st

Revision)



Chillers Standard Rating Conditions

1.) MS 1525:2007 Code of Practice on Energy Efficiency and Use ofRenewable Energy for Non-Residential Buildings (1st Revision)

Pg. 36 Section 8.11.1

Kw/Ton at

1.) 100% or Full load

2.) Part Load

Chiller Standard Performance Rating



Chiller Standard Performance RatingStandard

Eurovent

JISGBMS2449:2012



Performance

rating of water-chilling packagesusing the vapor

compression cycle

MS 2449:2012

Included in AHRI STD Certification Program for 50 HzEl t i l P



Electrical Power

1.) Centrifugal & Screw Chillers with ContinousLoading

2.) Rated 200 – 1,000 tons (703 – 3,517 KW ) at

Standard ARI Rating Conditions.3.) Hermetic & Open type, electric motor driven.

4.) Voltages up to 5,000 Volts.

Excluded in AHRI STD Certification Program for 50 HzEl t i l P



Electrical Power

1.) Scroll & Reciprocating compressor chillers with step unloading.2.) Condenserless Chillers.

3.)Evaporatively Cooled Chillers.

4.) Chillers below 200 tons and above 1000 tons.

5.) Chillers with Voltages above 5000 volts.

6.) Chillers powered by other than electric motor drives.

7.) Chillers with motors not supplied with the unit by themanufacturer.

8.) Air-Cooled Chillers.



6.1 ) Percent Load Weighting of Part Load Points1992 Std 1998 Std 2003 Std

100% 17% 1% 1%

75% 39% 42% 42%

50% 33% 45% 45%

25% 11% 12% 12%



6.2) Fouling factors (h.ft² F/Btu) or (m². c/w)1992 1998

Cooler 0.00025 0.0001

Condenser 0.00025 0.00025

A = kw/ton at 100% Load C = kw/ton at 50% Load

B = kw/ton at 75% Load D = kw/ton at 25% Load

WHAT TEMP. TO USE FOR PART LOAD PERFORMANCE FROM 100%DOWN TO 0%



DOWN TO 0%

7.) Entering Condenser Water Temp. commonlyused in Malaysia to evaluate Part LoadPerformance:

Percent Load ( 1 ) ( 2 )

F F F

100% 85 87 87

75% 75 87 85.25

50% 65 87 83.525% 65 87 81.75

0 % 65 87 80

Flow Rates and Temperatures



Flow Rates and Temperatures

2.4 gpm/ton[0.043 L/s/kW]

44°F[6.7°C]

54°F[12.2°C]

85°F29.4°C]

95°F [35°C]


ARIconditions


44°F[6.7°

54°F[12.2°C]

87°F[30.6°C]

97°F [36.1°C]


MalaysiaConditions

evaporatorflow rate

condenserflow rate

evaporatorflow rate

condenserflow rate

CHILLED

COOLING

TOWERS FCondenser water makeup

Typical Schematic of Chilled Water HVAC System



Theimportance

ofcontrollingthe flow of

air and waterin HVACsystems

T

AHU

CHILLED

WATER

SECONDARY

CHILLEDWATER PUMPS

AHU

CONDENSER WATER 35ºC

RETURN CONDENSER WATER 30ºC

15ºC

15ºC

15ºC

M A I N R

I S E R

R E T U R

N

9 - 1 2 º C

M A I N R

I S E R

F E E D 6

º C

T

T

T

T

T

T

F

FCU

F

F

F

F

F

F

CONDENSER

WATER PUMPS

F

AHU

15ºC

T

T

F

FFF

C O N D

E N S E R

E V A P O

R A T O R

PRIMARY CHILLED

WATER PUMPS

C H I L

L E R

3

C H I L

L E R

2

C H I L

L E R

1

RETURN

AIR FAN

By Air

By Air

By Water

By Refrigerant

Chil lers – Flow Rates and Temperatures



1-115

Why use 10

F and how much above can we go ?

•10 F = 2.4 USgpm/RT



Chil lers Flow Rates and Temperatures

Btuh = 500 x Q USgpm) x T deg F)

kWR = 4.187 x Q l/s) x Δ T deg C)

SavesEnergy

Equipment Rating Stds shouldn’t restrict us from designing more efficient CHW

system

Chiller Part Load Performance



1-116

IPLV / NPLV =____________1____________

0.01 + 0.42 + 0.45 + 0.12

A B C D

Where : A = KW/Ton at 100% , B = KW/Ton at 75 %

C = KW/Ton at 50 % , D = KW/Ton at 25 %

1%

42%

45%12%

50% Load

75% Load

25% Load100% Load

Full Load Vs Part Load



Full Load Vs Part Load

• Both FullPart and Part Load Efficiency can beimportant.

• Full Load- Design Based On ConsultantCalculation. (With or Without diversity factor)

– Part Load- May be running most of the time?

The arts and sciences of HVAC based on experience





MS 1525:2007

Code of Practice onEnergy Efficiency and

Use of Renewable

Energy for Non-Residential Buildings

(1st Revision)

8. Air-conditioning and mechanicalventilation (ACMV) system



ventilation (ACMV) system

8.1 Load calculations

8.2 System and equipment sizing

8.3 Separate air distribution systems

8.4 Controls

8.5 Piping insulation

8.6 Air handling duct system insulation

8.7 Duct construction8.8 Balancing

8. Air-conditioning and mechanicalventilation (ACMV) system



ventilation (ACMV) system

8.9 ACMV systems

8.10 ACMV system equipment

8.11 ACMV system components

8.12 ACMV system equipment/component

– heat operated (absorption), cooling mode

8.13 System testing and commissioning

8.14 Operation and maintenance (O&M) manualand as-built drawings

8.15 Preventive maintenance

8.1 Load calculations



8.1.1 Calculation procedures

Cooling system design loads for the purpose ofsizing systems and equipment should be

determined in accordance with the proceduresdescribed in the latest edition of the ASHRAEHandbook , or other equivalent publications.



8.1.2 Indoor design conditions



Room comfort condition is dependent on various

factors including air temperature, mean radianttemperature, humidity, clothing, metabolic rate andair movement preference of the occupant.

For the purpose of engineering design, room

comfort condition should consider the followingthree (3) main factors:

• dry bulb temperature;

• relative humidity; and

• air movement (air velocity)

8.1.4 Ventilation



Outdoor air-ventilation rates should comply with ThirdSchedule (By Law 41) Article 12(1) of UniformBuilding By Laws, 1984.

Exception: Outdoor air quantities may exceed those shown, ifrequired because of special occupancy or processrequirements or source control of air contamination or

Indoor Air Quality consideration.

8.2 System and equipment sizing



y q p g

8.2.1 Air conditioning systems and equipment shall besized to provide no more than the space and system

loads calculated in accordance with 8.1 above,consistent with available equipment capacity.Redundancy in capacity of equipment, if incorporatedinto the sizing of the duty equipment, should includeefficiency devices such as variable speed drive, highefficiency motor, efficient unloading devices, multicompressors etc so as not to diminish theequipment/system efficiency when operating atvarying loads.



8.2.2 Where chillers are used and when the design load

is greater than 1,000 kWr, a minimum of eithertwo chillers or a single multi-compressor chillershould be provided to meet the required load.

8.2.3 Multiple units of the same equipment type, such as

multiple chillers, with combined capacitiesexceeding the design load may be specified tooperate concurrently only if controls are providedwhich sequence or otherwise optimally control theoperation of each unit based on the required cooling

load.

8.4 Controls



8.4.1 Temperature control Each system should be provided with at leastone thermostat for the regulation of temperature.

Each thermostat should be capable of being set byadjustment or selection of sensors over aminimum range of between 22 C to 27 C.

Multi-stage thermostat should be provided for

equipment exceeding 35/65 kWr in conjunctionwith 8.2.4.

8 4 2 i i



8.4.2 Humidity control

In a system requiring moisture removal tomaintain specific selected relative humidity inspaces or zones, no new source of energy (suchas electric reheat) should be used to produce a

space relative humidity below 70 % forcomfort cooling purposes.

8.4.3 Energy Recovery

It is recommended that consideration be given to



It is recommended that consideration be given tothe use of recovery systems which will conserve

energy (provided the amount expended is less thanthe amount recovered) when the energy transfer

potential and the operating hours are considered.

Recovered energy in excess of the new source ofenergy expended in the recovery process may beused for control of temperature and humidity.

Examples include the use of condenser water for

reheat, desuperheater heat reclaim, heat recoverywheel, heat pipe or any other energy recoverytechnology.

8 4 5 M h i l til ti t l



8.4.5 Mechanical ventilation control

Each mechanical ventilation system (supplyand/or exhaust) should be equipped with areadily accessible switch or other means forshut-off or volume reduction when ventilation is

not required. Examples of such devices wouldinclude timer switch control, thermostatcontrol, duty cycle programming andCO/CO2 sensor control.



8.4.6 Fan System Efficiency

For fan system with air flowrate exceeding17000 m3/h and operating for more than 750hours a year, the power required by the motor

for the entire fan system at design conditionsshould not exceed 0.45 W per m3/h of airflowrate.

8.7 Duct construction



All ductwork should be constructed and erected in

accordance with HVAC Duct ConstructionStandards Metal and Flexible published bySMACNA or any other equivalent duct construction

standards.

8.7.1 High-pressure and medium-pressure ducts should be leak tested in accordance with HVAC Air DuctLeakage Test Manual published by SMACNA or

any other equivalent standards, with the rate ofleakage not to exceed the maximum rate specified.



8.8 Balancing

The system design should provide means for

balancing the air and water system such as but notlimited to dampers, temperature and pressure test

connections and balancing valves.

8.10 ACMV system equipment



• ACMV system equipment provides, in one (single package) or more (split system) factory assembled packages, means for air-circulation, air-cleaning, air-cooling with controlled temperature and

dehumidification. The cooling function may be eitherelectrically or heat operated, and the refrigerantcondenser may be air, water or evaporatively-cooled.

• Where the equipment is provided in more than one package, the separate packages should be designed bythe manufacturer to be used together.



LaunchedJuly 2007

8 13 System testing & commissioning



8.13 System testing & commissioning

• Air system balancing should be accomplished in amanner to minimise throttling losses and then fanspeed shall be adjusted to meet design flow conditions.

• Hydraulic system balancing should be accomplished ina manner to minimise throttling losses and then the

pump impeller should be trimmed or pump speedshould be adjusted to meet design flow conditions.

• ACMV control systems should be tested to assure thatcontrol elements are calibrated, adjusted and in properworking condition.

8 15 Preventive Maintenance



8.15 Preventive Maintenance

• The owner should implement preventive maintenancesystem and schedule periodic maintenance on all thecritical items of air-conditioning systems such as

compressors, cooling towers, pumps, condensers, airhandlers, controls, filters and piping.

AHU Room with Acoustical Problems



AHU Room with Acoustical Problems

What is Legionnaires’ Disease?



- Respiratory disease- Bacteria – Legionella pneumophilia

- Found in any aquatic environment

e.g; Cooling towers, evaporative condensers, showers, whirlpool spas, humidifies, decorative fountains, firesprinklers systems.

Sign and Symptoms of Legionnaires’ Disease



- Usually begins with a headache, pain in the muscles anda general feeling un-wellness.

- High fever (up to 40°-40.5 deg C or about 104-105deg.F) and shaking chills.

- Nausea, vomiting and diarrhea may occur

- Dry coughing and chest pain might occur

- 5 -15% of known cases have been fatal



Who is more likely to getLegionnaires’ disease?



Legionnaires disease?

- Middle aged or older people- Those who smoke tobacco or have chronic lung

disease

- Low resistance to infection / immune system

Workers most at risk

- Those who maintain cooling towers in air

conditioning systems

How to Prevent Legionnaires’ Disease?



a) Good engineering practices in the operation andmaintenance of the system.

- Cooling towers should be inspected and thoroughlycleaned at least once a year.

b) Corroded parts, such as drift eliminators should bereplaced.

c) Algae and accumulated scale should be removed.

d) Cooling towers water should be treated constantly.

Location of Cooling Towers



- Locate away from fresh air intakes.- Locate away from kitchen exhaust fans,

plants, truck bays, or other sources of

organic matter- Consider direction of prevailing wings.

- Consider future construction.

Industry Code of Practice on Indoor Air Quality 2010DOSH Malaysia* Ministry of Human Resources

Table 1: List of Indoor Air Contaminants and the Maximum Limits





Acceptable Range for SpecificPhysical Parameters – Proposed 2010

Parameter Acceptable range

(a) Air temperature

(b) Relative hum idity

(c) Air movement

23.0 – 26.0 ºC

40 – 70%

0.15 – 0.50



List of Indoor Air Contaminants and acceptable limits

Indo or Air Contaminants Eight-hou rs t ime-weighted average airborne

concentrat ion

ppm mg/m³ cfu/m³

Chemical contaminants

(a) Carbon d ioxid e

(b) Carbon mo noxid e

(c) Form aldehyde

(d) Ozone

(e) Resp irable part ic ulates

(f ) Total volat i le organic c ompounds(TVOC)

C1000

10

0.1

0.05

-

3

-

-

-

-

0.15

-

-

-

-

-

-

-

Biolog ical con taminants

(a) Total bacterial co unts

(b) Total fung al coun ts

-

-

-

-

500

1000

Carbon Dioxide and DCV



• CO2-based DCV has the mostenergy savings potential inbuildings where occupancy

fluctuates. – Office buildings, government

facilities, retail stores andshopping malls, airports,

theaters, auditoriums,conference or lecture halls,entertainment areas are goodcandidates for DCV





• Benefits – Improved IAQ – Increasing ventilation if CO2

levels rise to unacceptable levels.

– Improved humidity control – In humidclimates, DCV can prevent unnecessaryinfluxes of humid outdoor air that makesoccupants uncomfortable and encouragesmould & mildew growth

Typical Installation – AHU RoomReturn Air



AHU

AHU Room

Return Air

Supply Air

Fresh Air

Fresh air damper

Damper Actuator

CO2 sensor

Energy Monitoring



Air Handling Unit

Pt 500RTD

Pt 500 RTD

Energy meterEFC3500

DANFOSS

Flowmeter

FARADAY’S LAW



•

Ui = When an electrical conductor of length L ismoved at velocity v, perpendicular to the lines offlux through a magnetic field of strength B, thevoltage Ui is induced at the ends of theconductor.

• Ui = L x B x v

– Ui = Induced voltage

– L = Conductor length

– B = Magnetic field strength

– v = Velocity of conductor

The operation principle of inline magnetic flowmeters



Full Bore Flange Type

Type of Flow Meters



• Electronic Flow Meters – Full Bore Flange Type

Electromagnetic

Qualities

Obstruction free

No moving parts

Wide flow range

Virtually no maintenance

Minimal installation requirements

Typical accuracy at 0.25% and 0.5%

Full BMS Integration

Measures the velocities across thepipe line cross section

Insensitivity to viscosity, specificgravity, temperature and pressure

Respond well to fast changing flows

Lower life-cycle costs

When an electrical conductor

moved at velocity, perpendicularto the lines of flux through amagnetic field of strength, the

voltage is induced at the ends ofthe conductor

Type of Flow Meters

El t i Fl M t



Electronic Flow MetersUltrasonic

Obstruction freeNo moving partsWide flow rangeVirtually no maintenanceSensitive to pipe elbows and

control valvesRespond well to fast changingflowsFull BMS IntegrationLow Cost of Ownership onlarger pipe (>DN300)

Measuring PrincipleAcoustic flow measuring procedures likethe ultrasonic-flow measurement usesound waves above the hearing barrier,

i.e.> 20 kHz for speed and flowmeasurement. The velocity and directionof the sound rays change due to thetransport of the sound waves in the fluid.With the transit time procedure, the timeis measured in which a sound wave takesto get around path 1. I.e. point A, thesender

What is a “Green Design” or

Sustainable Design?



g

• ASHRAE GreenGuide provides one definition forsustainable building design:

“Sustainability is the providing of the

needs of the present without detractingfrom the ability to fulfill the needs of thefuture”

What’s Green Building? • USEPA- practice of creating structures and



• USEPA- practice of creating structures and

using processes that are environmentallyresponsible and resource-efficient throughout abuilding’s lifecycle from design ,construction,operation , maintenance,

renovation and even deconstruction.• - Sustainable or High-Performance building

• Source: IEM Jurutera June 2010 Bulletin

Green Building Rating System



AustraliaGreen Star

USALEEDEnergy StarGreen Globe

UK

BREEAM

SingaporeGreen Mark

CanadaLEED CanadaBREEAM Canada

Green Globe

Hong Kong HK-BEAM

JapanCASBEE

ItalyProtocolloITACA

Brazil

GBTool

KoreaGBTool

IndiaLEED-India

Taiwan綠建築標章

China绿色建筑评估标准

MalaysiaGBI

Green Building Rating System

• Australia: Nabers / Green Star• Brazil: AQUA / LEED Brasil• Canada: LEED Canada / Green Globes• China: GBAS

Fi l d P i E

http://www.ptm.org.my/wiki/Finland

http://www.ptm.org.my/wiki/People's_Republic_of_China

http://www.ptm.org.my/wiki/Canada

http://www.ptm.org.my/wiki/Brazil

http://www.ptm.org.my/wiki/Australia



• Finland: PromisE• France: HQE

• Germany: DGNB / CEPHEUS• Hong Kong: HKBEAM• India: GRIHA• Italy: Protocollo Itaca / Green Building Counsil Italia• Malaysia: GBI Malaysia• Mexico: LEED Mexico

• Netherlands: BREEAM Netherlands• New Zealand: Green Star NZ• Philippines: BERDE / Philippine Green Building Council• Portugal: Lider A• Singapore: Green Mark• South Africa: Green Star SA

• Spain: VERDE• Switzerland: Minergie• United States: LEED / Living Building Challenge / Green Globes /Build it Green / NAHB NGBS• United Kingdom: BREEAM• United Arab Emirates: Estidama

GLOBAL GREEN TOOLS

http://www.ptm.org.my/wiki/United_Arab_Emirates

http://www.ptm.org.my/wiki/United_Kingdom

http://www.ptm.org.my/wiki/United_States

http://www.ptm.org.my/wiki/Switzerland

http://www.ptm.org.my/wiki/Spain

http://www.ptm.org.my/wiki/South_Africa

http://www.ptm.org.my/wiki/Singapore

http://www.ptm.org.my/wiki/Portugal

http://www.ptm.org.my/wiki/Philippines

http://www.ptm.org.my/wiki/New_Zealand

http://www.ptm.org.my/wiki/Netherlands

http://www.ptm.org.my/wiki/Mexico

http://www.ptm.org.my/wiki/Malaysia

http://www.ptm.org.my/wiki/Italy

http://www.ptm.org.my/wiki/India

http://www.ptm.org.my/wiki/Hong_Kong

http://www.ptm.org.my/wiki/Germany

http://www.ptm.org.my/wiki/France

http://www.ptm.org.my/wiki/Finland



1. BREEAM, UK – Building Research Establishment

Environmental Assessment Method (1990)2. LEED, USA – Leadership in Energy and Environmental

Design (1996)

3. BEAM, Hong Kong – Building Environment AssessmentMethod (2003)

4. EEWH, Taiwan – Green Building Evaluation System (2003)

5. Green Star, Australia/New Zealand (2003)

6. CASBEE, Japan – Comprehensive Assessment System forBuilding Environmental Efficiency (2004)

7. Green Mark, Singapore (2005)8. Green Building Index, Malaysia (2009)

9. Greenship, Indonesia (2010)

GBI : An Integrated Design Approach



Workingtogether

to achieveGoals

Architect

CivilEngineer

MechanicalEngineer

ElectricalEngineerGBIF

QuantitySurveyor

Contractor

FM ServiceProvider

CommisiongSpecialist

EnergyConsultant

VendorsSub-cons

LandscapeArchitect

Owner /User



Building Energy Intensity



BEI = (TBEC - CPEC - DCEC)*(52/WOH)

(GFAex.cp - DCA - GLA*FVR)

where: “ex.cp” denotes excluding car park


(GFAexcl carpark - DCA - GLA*FVR)



( p )

Where;

TBEC: Total Building Energy Consumption (kWh/year) for alllandlord and tenancy areas.

CPEC: Carpark Energy Consumption (kWh/year) for carparkarea (which is not air-conditioned) and typically covers

artificial lighting, lifts, mechanical ventilation fans, sumppumps and plug loads (car washing facilities).Installations serving the whole building (such as hydraulicpumps and fire pumps) shall not be included.

DCEC: Data Centre Energy Consumption (kWh/year) for

operation of the Data Centre equipment and forcontrolling its indoor environment (air-conditioning,mechanical ventilation, lighting and plug loads).

GFAexcluding carpark : Gross Floor Area of buildings exclusiveof car park area (m2)


(GFAexcl carpark - DCA - GLA*FVR)



( p )

DCA: Gross area of Data Centre (m2)

GLA: Gross Lettable Area (m2) refers to the total functional usearea for commercial purposes such as office, retail,cafeteria, restaurant, gymnasium and club house insidethe building but excluding all common areas and service

areas. The sum of GLA, common areas and service areasshould equal the GFA excluding car park.

FVR: Floor Vacancy Rate is the weighted floor vacancy rate ofoffice, retail and other functional spaces of GLA. The FVR

(%) of GLA is equal to the non-occupied lettable area dividedby the GLA.

52: Typical weekly operating hours of office buildings inKL/Malaysia (hrs/wk) = 2,700 hrs/annum

WOH: Weighted Weekly Operating Hours of GLA exclusive ofDCA (hrs/wk)

BEI



EE5 pts Office Retail Hotel Hospital Etc

2 150 240 200 200 ?

3 140 225 190 190 ?5 130 210 175 175 ?

8 120 195 160 160 ?

10 110 180 150 150 ?12 100 160 135 135 ?

15 90 145 120 120 ?

• Separate metering provided for the following;

Electrical Sub-Metering



Separate metering provided for the following;

– Landlord and/or tenant

– Lift and escalator

– Major water pumping system

– Central air-conditioning system

– Car park and common area lighting/power system

– External and façade lighting

Separate electricity metering

to be linked to EMS





THANK YOU

Ir. NG YONG KONG, P.Eng., GBIF, MASHRAEEmail: [email protected]

Tel: +6012 –

201 9319

Documents

ACMV Systems.pdf