Refrigeration &

Air ConditioningBy

Harshvardhan Gandhi

2011B2A8641G

Refrigeration

• It can be defined as the process of transferring heatfrom a low temperature region to a high temperature region.

• In other words it is the process of cooling a substance.

• This can be achieved only if the heat is removed from that substance.

Principle of refrigeration

The principle of refrigeration is based on second law of thermodynamics. It states that heat does not flow from a low temperature body to a high temperature body without

the help of an external work.

Principle Since the heat has to be

transferred from a low temperature body to a high temperature body some external work has to be done according to the second law of thermodynamics. This external work is done by means of compressor, condenser etc.

This external work is done by means of

compressor, condenser etc.

Terms in refrigeration

1. Refrigerator:

It is a machine used to extract heat from a body at low

temperature and reject this heat to a body at high temperature. Thus it cools the body.

2. Refrigerant:

It is substance, which is used as a working fluid in refrigerators. The refrigerant has low boiling point, which means that it vaporizes at low temperature and takes away the heat from a substance.

3. Capacity of Refrigerator:

It is defined as the rate at which heat can be removed from the cold body.

4. Refrigeration Effect:

It is defined as the ratio of the quantity of heat removed to the time taken.

Refrigeration Effect = Heat removed / Time taken

5. Coefficient of Performance (COP):

It is defined as the ratio of heat absorbed in a given time (Refrigeration Effect) to the work done

COP = Refrigeration Effect / Work done

Vapor Compression Refrigeration System

Working Principle

• During evaporation, the refrigerant absorbs its latent heat of vaporization from the material that is to be cooled. Thus the body is cooled in the evaporator .

Then the low pressure vapor refrigerant enters the compressor and the cycle is repeated. Thus a material is cooled in vapor compression system

Air Condtioning

• Air conditioning is the process of altering the properties of air (primarily temperature and humidity) to more favorable conditions.

• The control of these conditions may be desirable to maintain the health and comfort of the occupants, or to meet the requirements of industrial processes irrespective of the external climatic conditions

Principle of Air Conditioning

TYPE OF AIR-CONDITIONING

1) Window air-conditioning system

To install one of these units, you need the space to make a slot in the wall, and there should also be some open space behind the wall.

when the summer heat dies down, these units can be easily removed for storage, and you can use the window sill for other purpose

2) Split Air-Conditioning System :• The split air conditioner comprises of two parts: the outdoor

unit and the indoor unit.

• The outdoor unit, fitted outside the room, houses components like the compressor, condenser and expansion valve.

• The indoor unit comprises the evaporator or cooling coil and the cooling fan.

3) Centralized Air-Conditioning System :

The central air conditioning plants or the systems are used when large buildings, hotels, theaters, airports, shopping malls etc. are to be air conditioned completely.

4) Packaged Air-Conditioning System :

The packaged air conditioners are used for the cooling capacities in between split air conditioners and centralised air conditioners.

Thank You!