VAPOUR COMPRESSION CYCLE
Introduction
The vapour compression cycle is the mostly widely used method of refrigeration in the modern application. Your household refrigerator, water cooler, deep freezer, air-conditioner etc, all run on vapour compression cycle. The cycle is called as vapour compression cycle, because the vapours of refrigerant are compressed in the compressor of the system to develop the cooling effect.
Working
Introduction
The vapour compression cycle is the mostly widely used method of refrigeration in the modern application. Your household refrigerator, water cooler, deep freezer, air-conditioner etc, all run on vapour compression cycle. The cycle is called as vapour compression cycle, because the vapours of refrigerant are compressed in the compressor of the system to develop the cooling effect.
Working
Here
are the various process of vapour compression cycle (refer the figure).
1) Compression: The
vapours of refrigerants enter the compressor and get compressed to high pressure and high temperature. During this process the entropy of the refrigerant ideally remains
constant
and
it
leaves
in super heated state.
2) Condensation:
The superheated refrigerant then enters
the
condenser where it
is cooled either by air or water due to which its temperature reduces,
but pressure remains constant and it gets converted into liquid
state.
3) Expansion:
The
liquid
refrigerant
then
enters
the
expansion
valve
or throttling valve or capillary tube when sudden expansion of the refrigerant occurs,
due to which its temperature and pressure
falls
down.
The refrigerant leaves expansion valve or capillary tube in partially
liquid state and partially
in gaseous state.
4) Evaporation or cooling: The partially
liquid
and
partially
gaseous refrigerant at very
low
temperature
enters
the
evaporator
where
the substance to be cooled is kept. It is here where the refrigeration effect is produced. The refrigerants absorbs
the
heat
from
the substance
to be cooled and gets converted into vapour state.
Fig : Simple VCR System
Advantages
» Capable of large refrigerating loads at lower
initial purchase
and operating cost.
» Very efficient
» Very compact system for small to very large heat loads.
» Cycle can be reversed
for heat pump operation.
Disadvantages
» Parts can wear out.
» Noise
» Potential refrigerant leaks.
» Operates in limited orientation.
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