Post on 08-Jan-2016
description
transcript
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 2/171
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: nyk@nyk.com.my
Tel: +6012 –
201 9319
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 3/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 4/171
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 )
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 5/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 6/171
Comfort Requirements
• Temperature
• Humidity
• Air movement
• Fresh air
• Clean air
• Noise level
• Lighting
• Furniture and work surfaces
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 7/171
ASHRAE Comfort Zone
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 8/171
ASHRAE Standard 55-2010
Specifiesconditions likelyto be thermally
acceptable to atleast 80% of theadult occupants
in a space
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 9/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 10/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 11/171
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).
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 12/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 13/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 14/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 15/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 16/171
Latent HeatTotal Heat = Sensible Heat + Latent Heat
Change of State
212° F
212° F
Section 2 – Basic Principles
Not measured ona thermometer
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 17/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 18/171
Four Components Are Required
4. Pressure/flow control
valve
2. Vaporpump
1. Heat absorbing section
3. Heat rejecting section
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 19/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 20/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 21/171
3. Psychrometrics
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 22/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 23/171
Why Study Psychrometrics?
Section 1 – Introduction
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 24/171
Dry-Bulb Thermometer
The temperature of air as measured by athermometer with a dry sensing bulb
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 25/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 26/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 27/171
Water Vapor in Air
Mechanical Mixture
Dry Air WaterVapor
Air + Vapor
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 28/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 29/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 30/171
Dry Bulb Temperature Scale
wb dp°F
db°F
Section 3 – Building the Psychrometric Chart
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 31/171
Dew Point Example
55° 67°
95° F
db100 gr
95°
100 gr
wb dp°F
db°F
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 32/171
Condensation Occurs atDew Point
Air Conditioning Clinic TRG-TRC001-EN © American Standard Inc. 1999
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 33/171
Relative Humidity Lines
Relative
Humidity Approx.
%4513260
132 gr
45%
75°
60 gr
wb dp°F
db°F
E th l S l
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 34/171
Enthalpy Scale
hs = 27.5 Btu/lb
wb dp°F
db°F
hs = Enthalpy at saturation
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 35/171
Psychrometric Chart
Dew PointTemperature
Dry BulbTemperature
Wet Bulb Temperature
SpecificHumidity
RelativeHumidity
wb dp°F
db°F
SpecificVolume
Enthalpy
Ai C diti i P
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 36/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 37/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 38/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 39/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 40/171
Using Enthalpy to Determine Total HeatRemoved
Latent Heat
Sensible Heat
55° 75°
wb dp°F
db°F
1.7
5.0
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 41/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 42/171
Cooling Coils
HeightLength
Face Area = Length Height
Velocity
Fins
Rows
cfm / face area
RefrigerantTemperature
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 43/171
ASHRAE Comfort Zone
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 44/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 45/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 46/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 47/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 48/171
Building code requirements
Extract from Third Schedule (By-law 41)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 49/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 50/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 51/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 52/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 53/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 54/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 55/171
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 )
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 56/171
ASHRAE Comfort Zone
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 57/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 58/171
5.) Refrigerant Issue-Environmental Impact
• ODP: Ozone Depletion Potential
• GWP: Global Warming Potential
• Climate Change
7 ) TYPES OF AIR CONDITIONING
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 59/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 60/171
Window Room Air Conditioner
Window room air conditioner
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 61/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 62/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 63/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 64/171
3. Air Cooled Split UnitsWarm air (recirculating)
Cool air
Outdoor air
Fan Coil Unit
Condensing Unit
3 Air Cooled Split Units (ACSUs)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 65/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 66/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 67/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 68/171
4b.) Air Cooled Split Units
Many Business Establishments are housedin Small Premises using ACSUs.
Office Restaurant
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 69/171
Shop Office
4b.) ACSUs Application
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 70/171
Advantages
• Low first cost• Flexibilities
• Easy to maintain
• Short lead time• Ex Stock
Other Systems
• Low Efficiency
• No Fresh Air
• Potential IAQ
issues
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 71/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 72/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 73/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 74/171
On a single refrigerant pipe, manyindoor units can be connected.
6. Variable Refrigerant System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 75/171
Advantages
• Flexibilities
• Better RH than ACSUs
• Space Saving
• Better EE than ACSUs
Others Systems
• Moderate EnergyEfficiencyCompared to
CHWS
• Potential IAQProblem
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 76/171
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)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 77/171
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)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 78/171
Conventional chilled water system
54°F
[12.2
C]
44°F
[6.7
C]
3-way valve
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 79/171
Primary-Secondary Configuration
primarypumps
two-way valve
Variablesecondarypump
distributionloop
productionloop
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 80/171
Variable-Primary-Flow Systems
two-wayvalve
Variable-flowpumps
control
valve
checkvalves
optional bypasswith three-way valve
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 81/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 82/171
ScrollReciprocating
Helical-RotaryScrew Centrifugal
Compressor
Type of Chiller Compressors(Hermetic or Semi-Hermetic)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 83/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 84/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 85/171
• 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 86/171
Centrifugal
Good variable Part Load Valuefor 4-season areas.
Low Ambient
Need to carefully Evaluate
Benefits.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 87/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 88/171
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+
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 89/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 90/171
Chilled Water System: Direct or ReverseReturn
DBCV - DYNAMIC BALANCING CONTROLVALVE
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 91/171
VALVEPICV – PRES. INDEPENDENT CONTROL
VALVE
Design• Pressure Independent
Control
• Automatic balancing• Commissioning
Save installation space & timeSave commissioning time &balancingEliminate error
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 92/171
Illuminated enclosure
GREEN: normal
RED: fault
Air Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 93/171
Methods of Air Flow Control
Air flow :•Outlet dampers•Inlet guide vanes•Variable pitch fan•Variable Speed Drive(VSD/VFD)
Water Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 94/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 95/171
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%
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 96/171
•There are two types of air
distribution systems
i.)CAV - Constant Air Volumeii.)VAV – Variable Air Volume
Air Distribution System – Supply Fan Basics
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 97/171
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
Air Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 98/171
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.
Air Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 99/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 100/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 101/171
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
Section 1 – Introduction
Air Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 102/171
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..
Air Distribution System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 103/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 104/171
Chiller Standard Performance RatingStandard
( Air-Conditioning, Heating
and Refrigeration Institute)
AHRI STD. 551/591 – 2011
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 105/171
MS 1525:2007
Code of Practice on
Energy Efficiency and
Use of RenewableEnergy for Non-
Residential Buildings
(1st
Revision)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 106/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 107/171
Chiller Standard Performance RatingStandard
Eurovent
JISGBMS2449:2012
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 108/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 109/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 110/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 111/171
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%
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 112/171
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%
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 113/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 114/171
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]
3.0 gpm/ton[0.054 L/s/kW]
ARIconditions
2.4 gpm/ton[0.043 L/s/kW]
44°F[6.7°
54°F[12.2°C]
87°F[30.6°C]
97°F [36.1°C]
3.0 gpm/ton[0.054 L/s/kW]
MalaysiaConditions
evaporatorflow rate
condenserflow rate
evaporatorflow rate
condenserflow rate
CHILLED
COOLING
TOWERS FCondenser water makeup
Typical Schematic of Chilled Water HVAC System
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 115/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 116/171
1-115
Why use 10
F and how much above can we go ?
•10 F = 2.4 USgpm/RT
•12 F = 2.0 USgpm/RT
•14 F = 1.7 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 117/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 118/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 119/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 120/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 121/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 122/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 123/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 124/171
8.1.2 Indoor design conditions
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 125/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 126/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 127/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 128/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 129/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 130/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 131/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 132/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 133/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 134/171
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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 135/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 136/171
• 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.
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 137/171
LaunchedJuly 2007
8 13 System testing & commissioning
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 138/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 139/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 140/171
AHU Room with Acoustical Problems
What is Legionnaires’ Disease?
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 141/171
- 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 142/171
- 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 143/171
Who is more likely to getLegionnaires’ disease?
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 144/171
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?
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 145/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 146/171
- 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 147/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 148/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 149/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 150/171
• 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
Carbon Dioxide and DCV
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 151/171
Carbon Dioxide and 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 152/171
AHU
AHU Room
Return Air
Supply Air
Fresh Air
Fresh air damper
Damper Actuator
CO2 sensor
Energy Monitoring
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 153/171
Air Handling Unit
Pt 500RTD
Pt 500 RTD
Energy meterEFC3500
DANFOSS
Flowmeter
FARADAY’S LAW
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 154/171
•
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 155/171
Full Bore Flange Type
Type of Flow Meters
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 156/171
• 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 157/171
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?
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 158/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 159/171
• 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 160/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 161/171
• 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 162/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 163/171
Workingtogether
to achieveGoals
Architect
CivilEngineer
MechanicalEngineer
ElectricalEngineerGBIF
QuantitySurveyor
Contractor
FM ServiceProvider
CommisiongSpecialist
EnergyConsultant
VendorsSub-cons
LandscapeArchitect
Owner /User
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 164/171
Building Energy Intensity
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 165/171
BEI = (TBEC - CPEC - DCEC)*(52/WOH)
(GFAex.cp - DCA - GLA*FVR)
where: “ex.cp” denotes excluding car park
BEI = (TBEC - CPEC - DCEC)*(52/WOH)
(GFAexcl carpark - DCA - GLA*FVR)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 166/171
( 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)
BEI = (TBEC - CPEC - DCEC)*(52/WOH)
(GFAexcl carpark - DCA - GLA*FVR)
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 167/171
( 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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 168/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 169/171
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
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 170/171
7/17/2019 ACMV Systems.pdf
http://slidepdf.com/reader/full/acmv-systemspdf 171/171
THANK YOU
Ir. NG YONG KONG, P.Eng., GBIF, MASHRAEEmail: nyk@nyk.com.my
Tel: +6012 –
201 9319