hvac for architects-1

8/9/2019 Hvac for Architects-1

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HVAC FOR ARCHITECTS AND

INTERIOR DESIGNERS

D.BALAJI

HVAC CONSULTANT


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WHAT IS HVAC


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ARE YOU COMFORTABLE


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ARE YOU COMFORTABLE


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Air conditioning can be defined as simultaneous control of the following to

maintain comfortable conditions

Temperature

Relative Humidity

WHAT IS AIR CONDITIONING

Air Flow

Air Purity

Noise

GOOD DESIGN EXCELLENT PERFORMANCE 6 ISHRAE CHENNAI CHAPTER


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WHAT THE AIR CONDITIONER DOES


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BENEFITS OF AIR CONDITIONING

A STUDY IN USA SHOWSTHAT DUE TO HVAC :

•15 % PRODUCTIVITY

INCREASE•EQUVALENT TO 180 BILLION

USD•INR 1080000 CRORES


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TOO HOT AND TOO COLD IS NOT AC


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COMFORT AIR-CONDITIONING


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PROCESS AIR-CONDITIONING


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PROCESS AIR-CONDITIONING


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DATA CENTRE AIR-CONDITIONING


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GOOGLE DATA CENTRE

POWER CONSUMPTION : 260 MW

( APRX 1000 CRORES ANNUAL POWER BILL )

MICROSOFT : 48 MW – YAHOO : 12 MW


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PROCESS AC – TURBULANCE AIR FLOW


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PROCESS AC – LAMINAR AIR FLOW


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PROCESS AIR-CONDITIONING–OP THEATRE


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SECTOR-WISE ENERGY CONSUMPTION


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ENERGY USAGE OF HVAC SYSTEMS


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ENERGY USAGE OF HOSPITAL


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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


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Losing Our CoolUncomfortable 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 air-

conditioners equals the amount of electricity

consumed by everyone in Africa.


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Fuel Energy In Power Plant

Transmission

and Distribution

Electric powered

System or process

3.37 kWh

Thermal

(11,500 Btu) (Thermal equivalent assuming 33% plant efficiency)

1.1kWh 1 kWh

delivered to

end use

CONCEPTUAL ILLUSTRATION OF CO2 EMISSIONS FROM ELECTIC END USE

OF ENERGY.

Coal Fuel - 1.14 KG of CO2 per KW of electricity


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AIR-CONDITIONERS AND ENVIRONMENT


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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


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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 .


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GREEN HOUSE EFFECT


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Between 1993 and 2005 sea level rose on average 3mm (0 1 inches) per year


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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


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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


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GREEN HOUSE EFFECT

GLOBAL WARMING


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GLOBAL WARMING

OZONE LAYER DEPLETION


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OZONE LAYER DEPLETION


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CAUGHT IN A VICIOUS

CIRCLE !

TEMPERATURE


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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

0 C


HEAT


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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.

HEAT

Some Sources of Heat in Air Conditioned Space

GOOD DESIGN EXCELLENT PERFORMANCE ISHRAE CHENNAI CHAPTER

Types of Heat


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Types of Heat

Sensible Heat Latent Heat

The Heat added or removed without change

in moisture content of air is termed as Sensible

Heat .

The Heat added or removed with change in

moisture content of air is termed as Latent

Heat .

Eg : - Eg : -

Electric Bulb

Purely Sensible !!

Zero Latent Heat

Only Heat Addition

No Moisture Addition

People

Sensible Heat ( normal body temperature 37 C )

+Latent Heat ( Respiration and Perspiration )

Heat Addition

Moisture Addition


Modes of Heat Transfer


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24 C

35 C

Conduction

Conduction is the transfer of heat from

molecule to molecule through a substance

by chain collision.

Convection

Radiation

of molecule from one place to another.

Radiation transfers heat by passing from a

source to an absorbent surface without

heating the space in Between.




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Ton of Refrigeration


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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.


British Thermal Unit ( Btu/hr )


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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.

1 Pound

Sensible Heat = 1 Pound x ( 33 - 32 )

= 1 BTU


Wet and Dry Bulb Temperature


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Wet and Dry Bulb Temperature

The temperature of the air

as measured by the ordinary

thermometer.

The temperature of the air as

measured by the ordinary

thermometer whose bulb

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


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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

Water

W lb

Mixture

( 1 + W ) lb


Relative Humidity


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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

1 lb

Water

W lb

Mixture

( 1 + W ) lb

Relative Humidity =W

Ws

W : moisture at saturated conditions

At Saturated Condition Air is having maximum amount of water particle beyond this moisture in air will condense.

X 100 = %


Relative Humidity


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Relative Humidity


PSYCHROMETRICS


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• Dry bulb temp.

• Wet bulb temp.

• Humidity

• Dew oint

PSYCHROMETRICS

• Moisture content

• Heating

• Cooling• Humidify

• De-Humidify

Psychrometric Chart

PSYCHROMETRICS


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PSYCHROMETRICS

PSYCHROMETRICS


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PSYCHROMETRICS

CHANGE OF PHASE


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CHANGE OF PHASE

CHANGE OF PHASE


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CHANGE OF PHASE

CHANGE OF PHASE


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CHANGE OF PHASE

CHANGE OF PHASE


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CHANGE OF PHASE

REFRIGERATION CYCLE


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Compressor

Condenser

REFRIGERATION CYCLE

Expansion

Valve

Evaporator

REFRIGERATION CYCLE


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REFRIGERATION CYCLE

REFRIGERATION CYCLE


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REFRIGERATION CYCLE

REFRIGERATION CYCLE


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REFRIGERATION CYCLE

REFRIGERATION CYCLE


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REFRIGERATION CYCLE

CONDENSER

EXPANSIONDEVICE

EVAPORATOR

COMPRESSOR

COMPONENTS - EVAPORATOR


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Evaporator

A

COMPONENTS EVAPORATOR

refrigerantrefrigerant

vapor vapor

mixture of mixture of

liquid and vaporliquid and vapor

refrigerantrefrigerant B

air air

COMPONENTS - COMPRESSOR


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Compressor

lowlow--pressurepressure

CB

highhigh--pressurepressure

COMPONENTS COMPRESSOR

from evaporator from evaporator

to condenser to condenser

COMPONENTS - CONDENSER


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Condenser

C

refri erantrefri erant

CO O S CO S

D

vapor vapor

liquidliquid

refrigerantrefrigerantoutdooroutdoor

air air

COMPONENTS – EXPANSION DEVICE


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Expansion Device

Dliquidliquid


mixture of mixture of

liquid and vaporliquid and vapor


ROTARY COMPRESSOR


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SCROLL COMPRESSOR


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RECIPROCATING – SCROLL COMPRESSOR


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SCROLL COMPRESSOR


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SCREW COMPRESSOR


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SCREW COMPRESSOR


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Comfortable Conditions


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Temperature and Humidity :

The comfort level varies with the application

APPLICATION TEMP -DEG C RELATIVE

HUMIDITY -%

COMFORT 24 +/- 1 AROUND 60

SERVER ROOM 20 +/- 1 < 50

OPERATION

THEATRES

22 +/- 1 50 +/- 5

Air Flow :

Air movement or velocity inside the air conditioned

space depends on application. Generally it is

around 25 fpm.



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Different Types of Heat Load


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External LoadInternal

Load

Infiltration & Ventilation Load


Building Survey


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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

Use of space

Doors

Stairways, Elevators and Escalators

Ceiling Height / False Ceiling Height

Columns and Beams

Construction Material

Surrounding Conditions

Windows

Lighting

Motors

Appliances

Ventilation

SOURCES OF HEAT


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Orientation of the Building


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N

S

EW

N W N E

S W S E

North

North

East

North

West

An Octagonal

South

SouthEast

SouthWest

Building


Flow of Heat in an Air Conditioned Space


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110 F or 43.3 C

Air Conditioned Room

75 F or 23.8 C

Non Air Conditioned

Room

105 F or 40.5 C

Window

Heat Reflecting

Glass



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HEAT LOAD - ESTIMATED TIME AND MONTH


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TIME : 4 PM - MONTH : MAY

Solar heat gain thru ordinary glass 10 deg Lat


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

Year Year

22-Dec

North 5 34 39 35 33 31 30 31 33 35 39 34 5 South

Northeast 42 127 148 135 109 56 22 14 14 13 11 7 1 Southeast

23-Jul East 50 135 158 142 98 43 14 14 14 13 11 7 1 East 21-Jan

& Southeast 26 57 66 56 32 14 14 14 14 13 11 7 1 Northeast &

21-May South 1 7 11 13 14 14 14 14 14 13 11 7 1 North 21-Nov

Southwest 1 7 11 13 14 14 14 14 32 56 66 5 7 26 Northwest

West 1 7 11 13 14 14 14 14 98 142 158 135 50 WestNorthwest 1 7 11 13 14 14 22 56 109 133 148 127 42 Southwest

Horizontal 3 42 1 07 1 66 2 10 236 247 236 210 1 66 107 42 3 Horizontal

EFFECT OF HEAT DUE TO ORIENTATION


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EXCESSIVE LIGHT AND HEAT


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GLASS : RADIATION AND CONDUCTION


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GLASS HEAT GAIN LOAD - SHGC


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SOLAR HEAT GAIN CO-EFFICIENT - SHGC


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SOLAR HEAT GAIN CO-EFFICIENT - SHGC


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The amount of solar

heat energy allowed to

pass through a window

Example: SHGC = 0.40Allows 40% through and

turns 60% away

GLASS : CONDUCTION


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SHGC AND U-VALUES FOR GLASS


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SHGC AND U-VALUES FOR GLASS - ECBC


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SHGC AND U-VALUES FOR GLASS


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WINDOW TYPES


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VELAVAN SHOPPING MALL - TUTICORIN


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VELAVAN SHOPPING MALL - TUTICORIN


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WALL HEAT GAIN LOAD


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WALL U-FACTOR


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Q = U x A x T

U-Value is the rate of heat

flow in Btu/h through aone ft2 area when one

side is 1oF warmer

WEST SIDE ORIENTATION


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UPVC WINDOWS AND FIRE RATED DOORS


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