Slide 1: REFRIGERATION AND AIR CONDITIONING Refrigeration may be defined as the process of removing heat from
a body or enclosed space so tat its temperature is first lowered and
then maintained at a level below the temperature of surroundings.
The system maintained at the lower temperature is known as
refrigerated system while equipment used to maintain this lower
temperature is known as refrigerating equipment.
Work is required to transfer heat from lower temperature body to
higher temperature body.
Amount heat removed by refrigerating equipment from
system is known as refrigerating effect. Unit – kJ/s.
Effectiveness of refrigeration is given by Co-efficient of
COP = Refrigerating effect/Work supplied Chetan M. Patel, R.K.College,India Slide 2: Applications Comfort air conditioning of auditoriums, hospitals, residents, offices, hotels etc.
Manufacturing and preservation of medicine.
Storage and transportation of food stuffs such as dairy products, fruits, vegetables, meat, fish etc.
Processing of textiles, printing work and photographics materials.
Manufacturing of ice.
Cooling of concrete for dam.
Treatment of air for blast furnace.
Processing of petroleum and other chemical products.
Production of Rocket fuel.
Computer functioning. Chetan M. Patel, R.K.College,India Slide 3: Refrigerant The working substance used in refrigeration equipment is known as refrigerant.
Some desirable properties of regrigerants are listed below.
High latent heat of evaporation and low specific volume.
Good thermal conductivity for rapid heat transfer.
Non-toxic, non-flamable and non-corrosive.
Low saturatio pressure.
Reasonable cost and should be available easily.
Stable and should decompose under any condition.
High critical pressure.
Commonoly used refrigerants are R12(CCl2F2), R22(CHClF2), NH3 , CO2, water and air. Chetan M. Patel, R.K.College,India Slide 4: Unit of Refrigeration The unit of refrigeration is ton of refrigeration or simply ton denoted by TR.
One ton of refrigeration means amount of heat required to remove from one short ton of water at 00C to produce ice at 00C at 24 hours.
The latent heat of ice is 334.9 kJ/Kg and one hourt tons equals to 907.18 kg therefore 1 ton of refrigeration equals to
1 TR = (334.9 x 907.18) / (24 x 3600)
= 3.516 kW Chetan M. Patel, R.K.College,India Slide 5: CLASSIFICATION Natural Refrigerators Mechanical Refrigerators Gas Refrigerators Vapour Refrigerators Vapour Compression Refrigerators Vapour
Absorption Refrigerators Chetan M. Patel, R.K.College,India Slide 6: Vapour Compression Refrigeration Cycle Slide 7: Advantages and Disadvantages ADVANTAGES:
Smaller in size.
Low running cost.
Temperature change by just control valve.
Requires greater safety and prevention of leaks due to the use of inflammable and toxic vaports of refrigerants.
Initial cost is high. Chetan M. Patel, R.K.College,India Slide 8: Vapour Absorption Refrigeration Cycle Slide 9: Air Regrigeration System Slide 10: Window Air Conditioning System Slide 11: Window Air Conditioning System Slide 12: Window Air Conditioning System Chetan M. Patel, R.K.College,India Slide 13: Split Air conditioning System Chetan M. Patel, R.K.College,India Slide 15: Split Air conditioning System Chetan M. Patel, R.K.College,India