The document discusses the vapor absorption cooling system (VACS), which utilizes a heat source and absorbents like lithium bromide and ammonia to drive the refrigeration process. VACS differs from vapor compression cooling systems (VCCS) in that it operates using waste heat, is less noisy, and has low maintenance costs, although it has a lower coefficient of performance (COP) and is bulkier. It is used in various applications such as cold storage, oil refineries, and air-conditioning, emphasizing its environmentally friendly properties by not using harmful refrigerants.

1. VAPOR ABSORPTION
COOLING SYSTEM
Muhammad Ali Haider
ME-09 B
SMME ,NUST

2. REFRIGERATION/COOLING
• Process of lowering the Temperature of the enclosed space by removing heat from it.
• A fluid called refrigerant is filled and flows through closed pipes , this process
completes by the phase change of the refrigerant.
• Common Refrigerants used for Refrigeration are ; R23 , R404A , R407A , Ammonia .
• Working Principle Of Refrigeration is the transfer of heat from low temperature
medium to High Temperature with the Addition of work to the system ; Clacius Law.
• Types of Refrigeration System
• Vapor Absorption cooling System(VACS)
• Vapor Compression cooling system(VCCS)

3. VAPOR ABSORPTION COOLING SYSTEM
(VCCS)
• Introduction:
An absorption refrigerator is a refrigerator that uses a heat source to provide the energy needed
to drive the cooling system. A vapor absorption system makes use of a substance, called
absorbent to absorb large volumes of the vapor of a refrigerant even when cold and reduce it to a
liquid, and subsequently give off its vapors when heated.
• Types:
 Single pressure absorption system
o Uses lithium bromide salt as absorbent & water as refrigerant.
 Water spray absorption system
 Simple absorption system
o Uses ammonia as refrigerant & water as absorbent.

4. VAPOR ABSORPTION COOLING SYSTEM
(VCCS)
• Principle
• Components
 Evaporator
 Vapor Generator
 Condenser
 Expansion Valve
Evaporato
r
Absorber
Pump
Condenser
GeneratorExpansion
Valve
1
23
4
Q’ in
W’ in
Q’ out
Qout
Q in

5. COMPARISON OF VCCS & VACS
• Both cycles circulate refrigerant inside the chiller to transfer heat from one fluid to the
other.
• VACS uses pump instead of compressor b/w evaporator & condenser to increase pressure
of Absorbent bcz it is in liquid phase at that stage.
• VACS uses refrigerants that have no bad effect on the Environment i.e Ammonia &
Lithium Bromide. But VCCS uses halocarbon i.e (HCFC-123, HCFC-22, HFC-134a).
• Performance of VACS is not sensitive to the load variation.
• VACS has low COP but it has low operation cost because it works on the waste heat of
powerplants.

6. • Advantages
• Less Noise
• Can be used to above 10000 ton Capacity.
• Corrosion Problem is less.
• Low Maintenance cost.
• Disadvantages
• Low COP
• Only Ammonia can be used as refrigerant.
• Bulky in Size

7. APPLICATIONS & BENEFITS
• It is mostly used in Cold Storage and icemaking Plants.
• It is used in Oil Refineries, Chemical Plants & Recreational Vehicles.
• VACS uses thermal energy to give instant chilled water for Co-generation Plant.
• Absorption chillers uses very little electricity compared to an electric motor driven
compression cycle chiller.
• It can be used to Air-Condition buildings by using waste heat of Cogeneration
Plant;Trigeneration.
• Absorption chillers do not use CFCs or HCFCs - the compounds known for causing Ozone
depletion.