AIR-CONDITIONING SYSTEM SUBMITTED BY: SANJIB KUMAR MANDAL ROLL NO: 97/ELM/104011
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 1/27
AIR-CONDITIONING SYSTEM
SUBMITTED BY:SANJIB KUMAR MANDAL
ROLL NO: 97/ELM/104011
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 2/27
INTRODUCTION TO AIR
CONDITIONING SYSTEMS
(a) Air conditioning is the removal of heat fromindoor air for thermal comfort.
(b) Air conditioning means conditioning of airfor maintaining specific conditions of temperature, relative humidity and low dust
levels inside an enclosed space.(c) An air conditioner is an appliance, system or
machine designed to change the airtemperature and humidity within an area(Used for cooling as well as heating
depending on the air properties at a giventime) typically using a refrigeration cyclebut sometimes using evaporation,commonly for comfort cooling in buildingsand motor vehicles.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 3/27
PURPOSE OF AIR CONDITIONING
• To control the temperature
• To control the humidity
•
To filtering the air to minimize dust• To provide moisture free dry air
• To remove air-borne bacteria
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 4/27
METHODS OF REFRIGERATION
• CHANGE OF PHASE
• EXPANSION OF A LIQUID
•
STEADY FLOW OF EXPANSION OF A PERFECTGAS
• EMPTYING PROCESS
•
ELECTRICAL PROCESSES
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 5/27
CYCLES USED FOR AIR CONDITIONING
• Vapor compression cycle
• Carnot refrigeration cycle
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 6/27
REFRIGERANT AND ITS PROPERTIES
• WHAT IS A REFRIGERANT ?
• BASIS OF SELECTION OF A REFRIGERANT
It depends upon three factors:(A)Thermodynamics
(B)Chemical
(C)Physical
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 7/27
COMPARISION OF FREEZING
TEMPERATURE OF DIFFERENT
REFRIGERANT
Refrigerants must operate above its freezing point temperature,making a low freezing point desirable. Freezing temperature of
different refrigerants are given below-• Ammonia -107˚F (-77.22 ˚C)
• Carbon dioxide -69.9˚F (-56.61 ˚C)
• Refrigerant 11 -168˚F (-111.11 ˚C)
• Refrigerant 22 -256˚F (-160 ˚C)
• Refrigerant 113 -31˚F (-35 ˚C)
• Water 32˚F (0˚C)
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 8/27
COMMONLY USED AIR
CONDITIONING SYSTEM
• (1) ROOM AIR CONDITIONER(RAC)
• (2) SPLIT AIR CONDITIONER(SAC)
•
(3) PACKAGE AIR CONDITIONER• (4) CENTRAL AIR CONDITIONING PLANTS
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 9/27
ROOM AIR CONDITIONER
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 10/27
HOW TO AVOID PROBLEM OF
INEFFICIENT FUNCTION OF RAC
• 1. Measure the air velocity per minute of the
supply grill air by using Anemometer and take
5 readings. Average air velocity = ((i) + (ii) +
(iii) + (iv) + (v))/5 (Say 959 ft. /min.)
• 2. Measure the Area of the supply Grill (say
0.5 sq. ft.)
• 3. Calculate the Air volume coming out of the
supply grill (say 480 cfm)
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 11/27
CONTINUED… • 4. Read the wet bulbs and Dry bulb
temperature of the supply air wet bulb 52.7°F
(11.5°C) Dry bulb 55.4°F(13°C)
• 5. Corresponding to the said wet bulb and dry
bulb temperature/ read the specific volume
of the supply air in the cubic feet per pound
from the enclosed psychometric chart. 13.1
cft/lb. (If chart is not available, 13.5 cft/lb may
be taken for practical purpose)
• 6. Calculate the Mass of the supply air by
dividing 3 by 5.(480/13.1)= 37 lbs/minute.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 12/27
CONTINUED… • 7. Read the Wet bulb temperature of the
Return air 66.2°F (19°C)WB.• 8. Calculate the total heat of the Return air
and supply air corresponding to wet bulb
temperature of Return air and supply air fromthe enclosed Table.
Return air 30.9 BTU/lb Say 31 BTU/lb.
Supply air 21.9 BTU/lb and 22 BTU/lb.Drop in the total heat
= 30.9 – 21.9 = 9 BTU/lb.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 13/27
CONTINUED… • 9. Capacity is equal to:
Mass of the supply air x Drop in total heat=37 x 9 BTU / min.= 333 x 60 BTU / lb.
=(333 x 60)/12000 = 1.6 Refrigeration Tons.
But to be sure regarding the capacity under any
situation,care to be taken whether the
difference in wet bulb temperature of the
supply air and return air is not less than 12°Fand also the air volume of the supply air is not
less than 400-500 cfm. for 1.5 Ton and 300-
350 cfm for 1 Ton machine.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 14/27
CENTRAL AIR CONDITIONING
PLANT
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 15/27
DEVICE USED IN CENTRAL AC PLANT
AND ITS FUNCTIONING
• 1. evaporator
• 2. compressor
•
3. condenser• 4. receiver
• 5. expansion device
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 16/27
THE VAPOR COMPRESSION CYCLE
Evaporator
Compressor
CondenserReceiver
ExpansionDevice
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 17/27
CHILLED WATER SYSTEM• Water chillers are used with duct or water
piping system.
• The water chiller contains a compressor, a
condenser, a thermal expansion valve and a
refrigerant evaporating coil.• Instead of cooling air as in vapor compression
system, the water chilled by the evaporation
coil.• The chilled water is then pumped into piping
system.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 18/27
FAN-COIL UNIT/AIR HANDLER
•It consists of :
• (1) the housing
• (2) the fan
• (3) the coils
• (4) face and bypass dampers
• (5) mixing box
• (6) fitters
• (7) spray humidifiers.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 19/27
REFRIGERATION BY ABSORPTION
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 20/27
ROUTINE MAINTENANCE • Unnecessary heat development in rotating
parts• Undue vibration and noise
• Checking of voltages and currents
• Oil level check• Leakage of refrigerant vapor
• Air Filter Changing
• Cleaning of water-cooled condensers
• Maintenance and servicing of water cooling-
towers
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 21/27
CONTINUED…
• Checking of water hardness
• Room Air-Conditioners
•
Water-cooled Packaged Units• Pump down of refrigerant system
• Cleaning of the Compressor
• Electrical system
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 22/27
HOW WE WILL DETERMINE
REQUIRED CAPACITY IN TONS?
• A general office measuring 30 ft. x 20 ft. x 12
ft. height is to be Air Conditioned. There are
floors above the office and the West wall is
made of brick. What will be the requiredcapacity in tons ?
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 23/27
CONTINUED… • i) Area of the office = 30 x 20 = 600 sq. ft.
• ii) Required capacity = 600 x 72 = 43200BTU/Hr = 3.6 Tons
• For 12 ft. height, if will be 3.6 / 9 x 12= 4.8 Tons
• iv) Add 10% Safety factor = 4.8 + 0.48= 5.28Tons
• So either 3 numbers 2 Tons capacity or 4
numbers 1.5 Tons capacity room AirConditioners should be recommended.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 24/27
ENERGY CONSERVATION IN THE
AREA OF REFRIGERATION
AND AIR CONDITIONG
• Energy conservation is now a tonic of the day
throughout the world and its bits are more feltin India and West Bengal in particular.
• The efficiency of an air conditioning and
refrigeration plant is expressed as the ratio of the refrigeration effect produced to the power
consumed (BTU per watt hour or kcal/Wh)
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 25/27
CONTINUED…
• This ratio, known as the ‘Energy Efficiency
Ratio’ (EER) is useful in comparing various
compressors as well as the performance of a
particular compressor at different operating
conditions.
• In a developing country like India 10 to 15% of
the total electricity produced, is used for
refrigeration and air-conditioning.
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 26/27
CONTINUED…
• A few method for consideration of Electrical
energy in the area of refrigeration and air-
conditioning area summarized below:
• Domestic Refrigeration and Air-conditioning
• Ice Bank Principle
• Heat Recovery System
•
Use of Centrifugal Compressor• Better Design of cooling tower
7/29/2019 Air Conditioning Systems-sanjib
http://slidepdf.com/reader/full/air-conditioning-systems-sanjib 27/27
THANK YOU