Tuesday, 1 September 2015

Vapor COMPRESSION REFRIGERATION SYSTEM



Vapor COMPRESSION REFRIGERATION SYSTEM
In the vapor pressure refrigeration framework, the refrigerant changes its stage from fluid to vapor and from vapor to fluid amid one cycle. Amid the vaporization handle the refrigerant assimilates the inactive warmth of vaporization from the refrigerated space and rejects the warmth to the surroundings amid the build-up stage. 
Figure demonstrates the piece graph of a vapor pressure framework and the T-S outline showing the four procedures that make the vapor pressure refrigeration cycle.
Process 1-2: Constant weight heat ingestion.
A blend of vapor and fluid at low temperature and weight assimilates heat from the evaporator as dormant warmth to change over all the fluid into vapor.
Process 2-3: Isotropic pressure of refrigerant vapor.
The low temperature and low weight vapor is packed in the compressor to a high weight super warmed vapor.
Process 3-4: Constant weight heat dismissal.
The super warmed vapor at high weight goes through the condenser where it is cooled by circling water or air consequently uprooting the inert warmth. The refrigerant changes stage to fluid.
Process 4-1: Adiabatic throttling development.

The high weight fluid is then extended adiabatic in a throttle valve. the sudden decrease in weight diminishes the temperature of the refrigerant. As the immersion temperature is low at low weight a percentage of the fluid changes stage to vapor and the fluid vapor blend enters the evaporator to rehash the cycle.
The vapor pressure strategy gives COPs of the request of 4 to 5. This is utilized most broadly as a part of present-day business refrigeration frameworks because of the high COP. It has the included point of interest of relatively littler size of gear as for different strategies because of warmth retention and dismissal as inert warmth rather than sensible warmth.
Vapor ABSORPTION REFRIGERATION SYSTEM
The vapor assimilation refrigeration framework works on the same succession of procedures as in the vapor pressure framework. The main distinction is that the compressor in the vapor pressure is supplanted by a vapor retention era unit comprising of
i)       absorber,
ii)      pump,
iii)     generator, and
iv)     expansion valve 
Figure demonstrates the piece graph of a smelling salts retention framework where alkali is the refrigerant water is the absorbent medium. The refrigeration technique is as per the following.
The low weight smelling salts vapor from the evaporator is caught up in water in a safeguard. The solid water arrangement is pumped to the generator through a warmth exchange. The solid water arrangement is warmed in the generator to discharge smelling salts vapor at high weight. The freed smelling salts goes to the condenser where it is consolidated and after that to the throttle valve for weight diminished. The fluid vapor smelling salts blend goes to the evaporator where it retains the dormant warmth and vanishes totally. The cycle is then rehashed.
In the ingestion – era unit the feeble water arrangement after arrival of smelling salts vapor comes back to the safeguard through the warmth exchange – to exchange some warmth to the solid water arrangement – and the development valve – to decrease the weight before admission to the safeguard. The feeble water arrangement is cooled in the safeguard to enhance its alkali assimilation limit.
Favorable circumstances over vapor pressure framework:
1.       lower commotion and upkeep because of disposal of compressor.
2.       low evaluation warmth sources can be utilized.
3.       high limits, well over 1000 tons, can be constructed.
4.       less electrical vitality utilization – just for pumping.
The drawbacks are:
1.       low COP (0.5 to 0.7) when contrasted with vapor pressure.
2.       as a bigger number of types of gear are utilized than as a part of a vapor pressure framework, can be efficient just if some waste warmth or second rate warmth sources are available.

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