DEPARTMENT OF MECHANICAL ENGINEERING
LAB MANUAL
SUBJECT: REFRIGERATION & AIR CONDITIONING
ACADEMIC YEAR: 2026-27
1
,SR. NO. NAME OF EXPERIMENTS
1 Study of air-refrigeration cycle.
2 Study vapor compression cycle.
Study of different vapor absorption refrigeration systems and to calculate the
3
COP of Electrolux vapor absorption system.
4 Study of various components of VCR system.
To understand various tools used for refrigeration tubing and various
5
operations like flaring, bending, brazing.
To understand the different psychrometric processes and analyze the same
6
using psychrometric chart.
To calculate the cooling load of the confined space and compare the same
7
with load estimation sheet.
8 To study domestic refrigerator.
9 To study air-washer.
10 To study about window and split type air-conditioner.
11 To study about different types of refrigerants.
2
, 1. Aim:- Study of air-refrigeration cycle.
➢ Why use air cycle?
Air cycle systems have specific advantages that apply to all potential applications:
• The working fluid (air) is free, environmentally benign, safe and non-toxic
• Air cycle equipment is extremely reliable, reducing maintenance costs and system down-time
• The performance of an air cycle unit does not deteriorate as much as that of a vapour-compression unit
when operating away from its design point
• When operating in a refrigeration cycle, an air cycle unit can also produce heat at a useful temperature. If
this is used together with the cooling, highly efficient, low energy processes are possible
• Air cycle units can produce a much higher temperature difference between the hot and cold sides
compared to vapour-compression units. This means that: o Very cold air can be produced for near-
cryogenic processes o Heat can be produced at a useful temperature, which, if used together with the
cooling, can result in highly efficient, low energy processes.
➢ How does air cycle work?
Air cycle refrigeration works on the reverse Brayton or Joule cycle. Air is compressed and then heat
removed, this air is then expanded to a lower temperature than before it was compressed. Work must be
taken out of the air during the expansion, otherwise the entropy would increase. Work is taken out of the
air by an expansion turbine, which removes energy as the blades are driven round by the expanding air.
This work can be usefully employed to run other devices, such as generators or fans. Often, though, it is
used to power a directly connected (bootstrap) compressor, which elevates the compressed (hot) side
pressure further without added external energy input, essentially recycling the energy removed from the
expanding air to compress the high pressure air further. The increase in pressure on the hot side further
elevates the temperature and makes the air cycle system produce more useable heat (at a higher
temperature). The cold air after the turbine can be used as a refrigerant either directly in an open system,
or indirectly by means of a heat exchanger in a closed system. The efficiency of such systems is limited to a
great extent by the efficiencies of compression and expansion, as well as those of the heat exchangers
employed. Originally, slow speed reciprocating compressors and expanders were used. The poor efficiency
and reliability of such machinery were major factors in the replacement of such systems with vapour
compression equipment. However, the development of rotary compressors and expanders (such as in car
turbochargers) greatly improved the isentropic efficiency and reliability of the air cycle. Advances in
turbine technology, together with the development of air bearings and ceramic components offer further
efficiency improvements. Combining these advances with newly available, compact heat exchangers, which
have greatly improved heat transfer characteristics, makes competition with many existing vapour
compression quite feasible.
3
, The components of the air refrigeration system are shown in Fig.6.3 (a). In this system, air is taken into the
compressor from atmosphere and compressed. The hot compressed air is cooled in heat exchanger up to
the atmospheric temperature (in ideal conditions). The cooled air is then expanded in an expander. The
temperature of the air coming out from the expander is below the atmospheric temperature due to
isentropic expansion. The low temperature air coming out from the expander enters into the evaporator
and absorbs the heat. The cycle is repeated again. The working of air-refrigeration cycle is represented on
p-v and T-s diagrams in Fig.6.3 (b) and (c).
4
LAB MANUAL
SUBJECT: REFRIGERATION & AIR CONDITIONING
ACADEMIC YEAR: 2026-27
1
,SR. NO. NAME OF EXPERIMENTS
1 Study of air-refrigeration cycle.
2 Study vapor compression cycle.
Study of different vapor absorption refrigeration systems and to calculate the
3
COP of Electrolux vapor absorption system.
4 Study of various components of VCR system.
To understand various tools used for refrigeration tubing and various
5
operations like flaring, bending, brazing.
To understand the different psychrometric processes and analyze the same
6
using psychrometric chart.
To calculate the cooling load of the confined space and compare the same
7
with load estimation sheet.
8 To study domestic refrigerator.
9 To study air-washer.
10 To study about window and split type air-conditioner.
11 To study about different types of refrigerants.
2
, 1. Aim:- Study of air-refrigeration cycle.
➢ Why use air cycle?
Air cycle systems have specific advantages that apply to all potential applications:
• The working fluid (air) is free, environmentally benign, safe and non-toxic
• Air cycle equipment is extremely reliable, reducing maintenance costs and system down-time
• The performance of an air cycle unit does not deteriorate as much as that of a vapour-compression unit
when operating away from its design point
• When operating in a refrigeration cycle, an air cycle unit can also produce heat at a useful temperature. If
this is used together with the cooling, highly efficient, low energy processes are possible
• Air cycle units can produce a much higher temperature difference between the hot and cold sides
compared to vapour-compression units. This means that: o Very cold air can be produced for near-
cryogenic processes o Heat can be produced at a useful temperature, which, if used together with the
cooling, can result in highly efficient, low energy processes.
➢ How does air cycle work?
Air cycle refrigeration works on the reverse Brayton or Joule cycle. Air is compressed and then heat
removed, this air is then expanded to a lower temperature than before it was compressed. Work must be
taken out of the air during the expansion, otherwise the entropy would increase. Work is taken out of the
air by an expansion turbine, which removes energy as the blades are driven round by the expanding air.
This work can be usefully employed to run other devices, such as generators or fans. Often, though, it is
used to power a directly connected (bootstrap) compressor, which elevates the compressed (hot) side
pressure further without added external energy input, essentially recycling the energy removed from the
expanding air to compress the high pressure air further. The increase in pressure on the hot side further
elevates the temperature and makes the air cycle system produce more useable heat (at a higher
temperature). The cold air after the turbine can be used as a refrigerant either directly in an open system,
or indirectly by means of a heat exchanger in a closed system. The efficiency of such systems is limited to a
great extent by the efficiencies of compression and expansion, as well as those of the heat exchangers
employed. Originally, slow speed reciprocating compressors and expanders were used. The poor efficiency
and reliability of such machinery were major factors in the replacement of such systems with vapour
compression equipment. However, the development of rotary compressors and expanders (such as in car
turbochargers) greatly improved the isentropic efficiency and reliability of the air cycle. Advances in
turbine technology, together with the development of air bearings and ceramic components offer further
efficiency improvements. Combining these advances with newly available, compact heat exchangers, which
have greatly improved heat transfer characteristics, makes competition with many existing vapour
compression quite feasible.
3
, The components of the air refrigeration system are shown in Fig.6.3 (a). In this system, air is taken into the
compressor from atmosphere and compressed. The hot compressed air is cooled in heat exchanger up to
the atmospheric temperature (in ideal conditions). The cooled air is then expanded in an expander. The
temperature of the air coming out from the expander is below the atmospheric temperature due to
isentropic expansion. The low temperature air coming out from the expander enters into the evaporator
and absorbs the heat. The cycle is repeated again. The working of air-refrigeration cycle is represented on
p-v and T-s diagrams in Fig.6.3 (b) and (c).
4
