HVAC FOR ARCHITECTS AND
INTERIOR DESIGNERS
D.BALAJI
HVAC CONSULTANT
WHAT IS HVAC
ARE YOU COMFORTABLE
ARE YOU COMFORTABLE
WHAT IS AIR CONDITIONING
Air conditioning can be defined as simultaneous control of the following to
maintain comfortable conditions
Temperature
Relative Humidity
Air Flow
Air Purity
Noise
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
WHAT THE AIR CONDITIONER DOES
BENEFITS OF AIR CONDITIONING
STUDY IN USA SHOWS
THAT DUE TO HVAC :
15 % PRODUCTIVITY
INCREASE
EQUVALENT TO 180 BILLION
USD
INR 1080000 CRORES
TOO HOT AND TOO COLD IS NOT AC
COMFORT AIR-CONDITIONING
PROCESS AIR-CONDITIONING
PROCESS AIR-CONDITIONING
DATA CENTRE AIR-CONDITIONING
GOOGLE DATA CENTRE
POWER CONSUMPTION : 260 MW
( APRX 1000 CRORES ANNUAL POWER BILL )
MICROSOFT : 48 MW YAHOO : 12 MW
PROCESS AC TURBULANCE AIR FLOW
PROCESS AC LAMINAR AIR FLOW
PROCESS AIR-CONDITIONINGOP THEATRE
SECTOR-WISE ENERGY CONSUMPTION
ENERGY USAGE OF HVAC SYSTEMS
ENERGY USAGE OF HOSPITAL
SCOPE OF POWER SAVING IN CHENNAI
COMMERCIAL SECTOR POWER CONSUMPTION IN CHENNAI
2500 MILLION UNITS IN 2013
ESTIMATED POWER CONSUMPTION BY HVAC
560 MILLION UNITS ( Rs.400 CRORES )
ESTIMATED MINIMUM POWER SAVING 10 %
56 MILLION UNITS
IN TERMS OF POWER COST
Rs.40 CRORES
Losing Our Cool
Uncomfortable Truths about Our Air-Conditioned World
(and Finding New Ways to Get through the Summer)
If rest of the world uses the same level of AC
like USA then the power demand will go by 50
times.
China expected to cross USA by 2020 in AC
usage.
40 % of all electricity in Mumbai goes for AC
By 2028 Saudi Arabia will consume more fuel
than it can export due to AC
Global usage of AC by 2050 will be 8 fold more
than today.
Power consumed by Americans for running airconditioners equals the amount of electricity
consumed by everyone in Africa.
Fuel Energy In
Electric powered
System or process
Power Plant
Transmission
and Distribution
1.1kWh
3.37 kWh
Thermal
(11,500 Btu)
1 kWh
delivered to
end use
(Thermal equivalent assuming 33% plant efficiency)
Coal Fuel - 1.14 KG of CO2 per KW of electricity
CONCEPTUAL ILLUSTRATION OF CO2 EMISSIONS FROM ELECTIC END USE
OF ENERGY.
AIR-CONDITIONERS AND ENVIRONMENT
GREEN
HOUSE
EFFECT
Worldwide levels of the
chief greenhouse gas that
causes global warming have
hit a milestone, reaching an
amount never before
encountered by humans
GLOBAL WARMING CO2 CONCENTRATION
"At the current rate of increase, the global
annual average CO2 concentration is set to
cross the 400 ppm threshold in 2015 or 2016,"
the UN agency said .
GREEN HOUSE EFFECT
Between 1993 and 2005 sea level rose, on average, 3mm (0.1 inches) per year,
attributed to an increase in melting ice and thermal expansion as the ocean absorbs
excess energy.
The 2007 IPCC report conservatively predicts that sea levels could rise 10 to 23
inches by 2100 if current warming patterns continue.
GREEN HOUSE EFFECT
GLOBAL WARMING
OZONE LAYER DEPLETION
CAUGHT IN A VICIOUS
CIRCLE !
TEMPERATURE
Temperature indicates the average kinetic energy of the molecules of a substance.
Temperature can also be defined as measure of intensity of Heat in a substance.
98 F or 36.6 C
32F
or
0C
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
HEAT
Heat is the total amount of energy possesses by the molecules in a piece of matter.
This energy is sum of both kinetic energy and potential energy of the molecules.
Heat is a form of energy which transfers from Higher Side to Lower Side.
Some Sources of Heat in Air Conditioned Space
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
Types of Heat
Sensible Heat
Latent Heat
The Heat added or removed without change
The Heat added or removed with change in
in moisture content of air is termed as Sensible
moisture content of air is termed as Latent
Heat .
Heat .
Eg : -
Eg : People
Electric Bulb
Only Heat Addition
Heat Addition
No Moisture Addition
Moisture Addition
Sensible Heat ( normal body temperature 37 C )
Purely Sensible !!
Zero Latent Heat
GOOD DESIGN EXCELLENT PERFORMANCE
Latent Heat ( Respiration and Perspiration )
ISHRAE CHENNAI CHAPTER
Modes of Heat Transfer
35 C
Conduction is the transfer of heat from
Conduction
molecule to molecule through a substance
24 C
by chain collision.
Convection is heat transfer by the movement
Convection
of molecule from one place to another.
Radiation transfers heat by passing from a
Radiation
source to an absorbent surface without
heating the space in Between.
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
Modes of Heat Transfer
Ton of Refrigeration
One Ton of Refrigeration is defined as the quantity of heat added to melt
one ton of ice at 32 degree F ( 0 degree C ) to water at the same temperature
in 24 hours or vice versa.
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
British Thermal Unit ( Btu/hr )
One British thermal unit is defined as the amount of heat to be added
( removed ) to raise ( lower ) the temperature of one pound of water
by One Degree F.
33 F
1 Pound
Sensible Heat = 1 Pound x ( 33 - 32 )
= 1 BTU
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
Wet and Dry Bulb Temperature
The temperature of the air as
The temperature of the air
measured by the ordinary
as measured by the ordinary
thermometer whose bulb
thermometer.
is covered by a wetted wick
or cloth and exposed to
a current of rapidly moving
air.
GOOD DESIGN EXCELLENT PERFORMANCE
10
ISHRAE CHENNAI CHAPTER
Specific Humidity
The Specific Humidity is the weight of water vapour
in grains or pounds of moisture per pound of dry air.
Dry Air
1 lb
GOOD DESIGN EXCELLENT PERFORMANCE
Mixture
Water
W lb
( 1 + W ) lb
11
ISHRAE CHENNAI CHAPTER
Relative Humidity
The Relative Humidity is the ratio of actual amount of
moisture present in one unit volume of dry air to the
amount of moisture needed to saturate it at that
temperature
Dry Air
Mixture
Water
W lb
1 lb
( 1 + W ) lb
Relative Humidity =
W
X 100 =
Ws
Ws : moisture at saturated condition
At Saturated Condition Air is having maximum amount of water particle beyond this moisture in air will condense.
GOOD DESIGN EXCELLENT PERFORMANCE
12
ISHRAE CHENNAI CHAPTER
Relative Humidity
GOOD DESIGN EXCELLENT PERFORMANCE
13
ISHRAE CHENNAI CHAPTER
PSYCHROMETRICS
Dry bulb temp.
Wet bulb temp.
Humidity
Dew point
Moisture content
Heating
Cooling
Humidify
De-Humidify
Psychrometric Chart
PSYCHROMETRICS
PSYCHROMETRICS
CHANGE OF PHASE
CHANGE OF PHASE
CHANGE OF PHASE
CHANGE OF PHASE
REFRIGERATION CYCLE
Condenser
Compressor
Expansion
Valve
Evaporator
REFRIGERATION CYCLE
REFRIGERATION CYCLE
REFRIGERATION CYCLE
REFRIGERATION CYCLE
CONDENSER
EXPANSION
DEVICE
EVAPORATOR
COMPRESSOR
COMPONENTS - EVAPORATOR
Evaporator
A
mixture of
liquid and vapor
refrigerant
refrigerant
vapor
air
COMPONENTS - COMPRESSOR
Compressor
B
low-pressure
lowrefrigerant vapor
from evaporator
C
high-pressure
highrefrigerant vapor
to condenser
COMPONENTS - CONDENSER
Condenser
C
refrigerant
vapor
D
outdoor
air
liquid
refrigerant
COMPONENTS EXPANSION DEVICE
Expansion Device
mixture of
liquid and vapor
refrigerant
liquid
refrigerant
ROTARY COMPRESSOR
SCROLL COMPRESSOR
RECIPROCATING SCROLL COMPRESSOR
SCROLL COMPRESSOR
SCREW COMPRESSOR
SCREW COMPRESSOR
Comfortable Conditions
Temperature and Humidity :
The comfort level varies with the application
APPLICATION
TEMP -DEG C
RELATIVE
HUMIDITY -%
COMFORT
24 +/- 1
AROUND 60
SERVER ROOM
OPERATION
THEATRES
20 +/- 1
22 +/- 1
< 50
50 +/- 5
Air Flow :
Air movement or velocity inside the air conditioned
space depends on application. Generally it is
around 25 fpm.
GOOD DESIGN EXCELLENT PERFORMANCE
ISHRAE CHENNAI CHAPTER
Different Types of Heat Load
Internal
Load
External Load
Infiltration & Ventilation Load
GOOD DESIGN EXCELLENT PERFORMANCE
17
ISHRAE CHENNAI CHAPTER
Building Survey
An accurate survey of the load components of the space to be air conditioned is basic
requirement for realistic estimate of cooling and heating loads. During the survey the
below mentioned points should be considered.
Orientation of building
Doors
Use of space
Stairways, Elevators and Escalators
Physical Dimension of Space
People
Ceiling Height / False Ceiling Height
Lighting
Columns and Beams
Motors
Construction Material
Appliances
Surrounding Conditions
Ventilation
Windows
SOURCES OF HEAT
Orientation of the Building
N
North
NE
NW
North
East
North
West
W
SE
SW
S
An Octagonal
Building
West
East
South
West
South
East
South
GOOD DESIGN EXCELLENT PERFORMANCE
19
ISHRAE CHENNAI CHAPTER
Flow of Heat in an Air Conditioned Space
110 F or 43.3 C
Air Conditioned Room
Non Air Conditioned
Room
105 F or 40.5 C
75 F or 23.8 C
Window
Heat Reflecting
Glass
GOOD DESIGN EXCELLENT PERFORMANCE
20
ISHRAE CHENNAI CHAPTER
HEAT LOAD - ESTIMATED TIME AND MONTH
TIME : 4 PM - MONTH : MAY
Solar heat gain thru ordinary glass 10 deg Lat
Time of Exposure
Year
10
11
12
6 Exposure Time of
Year
22-Dec
North
Northeast
23-Jul East
&
Southeast
21-May South
Southwest
West
Northwest
Horizontal
5 34 39 35 33 31 30
42 127 148 135 109 56 22
50 135 158 142 98 43 14
26 57 66 56 32 14 14
1
7 11 13 14 14 14
1
7 11 13 14 14 14
1
7 11 13 14 14 14
1
7 11 13 14 14 22
3 42 107 166 210 236 247
31
14
14
14
14
14
14
56
236
33 35 39 34 5 South
14 13 11 7 1 Southeast
14 13 11 7 1 East
21-Jan
14 13 11 7 1 Northeast
&
14 13 11 7 1 North
21-Nov
32 56 66 57 26 Northwest
98 142 158 135 50 West
109 133 148 127 42 Southwest
210 166 107 42 3 Horizontal
EFFECT OF HEAT DUE TO ORIENTATION
EXCESSIVE LIGHT AND HEAT
GLASS : RADIATION AND CONDUCTION
GLASS : RADIATION AND CONDUCTION
GLASS HEAT GAIN LOAD - SHGC
SOLAR HEAT GAIN CO-EFFICIENT - SHGC
SOLAR HEAT GAIN CO-EFFICIENT - SHGC
The
amount of solar
heat energy allowed to
pass through a window
Example:
SHGC = 0.40
Allows 40% through and
turns 60% away
GLASS : CONDUCTION
SHGC AND U-VALUES FOR GLASS
SHGC AND U-VALUES FOR GLASS - ECBC
SHGC AND U-VALUES FOR GLASS
WINDOW TYPES
VELAVAN SHOPPING MALL - TUTICORIN
VELAVAN SHOPPING MALL - TUTICORIN
WALL HEAT GAIN LOAD
WALL U-FACTOR
Q = U x A x T
U-Value is the rate of heat
flow in Btu/h through a
one ft2 area when one
side is 1oF warmer
WEST SIDE ORIENTATION
UPVC WINDOWS AND FIRE RATED DOORS
