10-08-2013, 04:35 PM
INTRODUCTION TO VAPOUR ABSORPTION SYSTEM
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Introduction To Vapour Absorption System
The phasing out of CFC based refrigerants is an important aspect in greening the industry.
There are several ways of achieving this objective- replacing the refrigerant or installing Vapour
Absorption System.In this context,vapour absorption system is gaining immense popularity.
In addition to being eco-friendly,VAS offers tremendous power savings .
The absorption chiller is a machine, which produces chilled water by using heat such as steam,
hot water, gas, oil etc. Chilled water is produced by the principle that liquid (refrigerant), which
evaporates at low temperature, absorbs heat from surrounding when it evaporates. Pure water
is used as refrigerant and lithium bromide solution is used as absorbent
Heat for the vapour absorption refrigeration system can be provided by waste heat extract-
ed from process, diesel generator sets etc. Absorption systems require electricity to run pumps
only. Depending on the temperature required and the power cost, it may even be economical to
generate heat / steam to operate the absorption system.
Types of VAS System:
There are two types of VAS- the single effect and the Double effect.The major
d ifference between the Single effect and Double effect machines is that the Double
Effect VAS has one additional Generator called Low Temperature Generator. In low
Temperature generator the absorbent is further concentrated using the vapour.
Advantages of Vapour Absorption System
The main advantages of installing VAHP are as follows:
* Environment friendly (No CFCs and hence a “Green Technology”)
* Very low power consumption (fractional power for refrigerant pump)
* Part load efficiency is as good as efficiencies at full load.
* Requires negligible maintenance since there are no moving parts
* Noiseless and vibration free operation