In this article, I will share with you the components and working principle of the vapour absorption refrigeration system.
The vapour absorption refrigeration system is kinda similar to the vapour compression system since both systems have a condenser and an evaporator.
Though there are some differences that I want you to recognize before you confuse these two systems.
The difference between vapour absorption refrigeration system and vapour compression refrigeration system are;
- In the vapour absorption refrigeration system there is an introduction of a generator while the vapour compression refrigeration system has a compressor.
- Pressure in the vapour absorption system is achieved by pumping the strong solution into the generator while the development of pressure in the vapour compression refrigeration system is achieved by compression.
- The vapour absorption refrigeration system uses a pressure-reducing valve to reduce the pressure of the liquid refrigerant while in the vapour compression refrigeration system pressure is reduced by the expansion valve.
- In a vapour absorption refrigeration system the vapour refrigerant has to be absorbed by the adsorbent to form a liquid before it’s taken to the generator while in a vapour compression refrigeration system the vapour is used in the same phase it’s in.
Now, that you have a hint about the differences between these two systems it will be easier for you to understand the working principle.
Before I share with you the working principle of the vapour absorption refrigeration system, you have to know its components and how they work.
Components of vapour absorption refrigeration system and their functions.
These are the main components of the vapour absorption refrigeration system and their functions;
Evaporator; the main function of the evaporator is to accommodate the refrigerant that is used for heat absorption from the medium that needs to be cooled.
The absorber; has an adsorbent that is used to absorb the vapour refrigerant from the evaporator to form the strong solution used in the refrigeration cycle.
A pump; it’s used to pump the strong solution formed by the absorber to the generator. Also by pumping the strong solution it raises its pressure.
Generator; it’s the part where the strong solution is heated to regenerate the vapour refrigerant from the strong solution, rendering it weak.
Condenser; it’s the device that cools the vapour refrigerant driven off from the strong solution so that it’s qualified.
Absorbent; is the solution that absorbs refrigerant vapour in the absorber to form a strong solution.
Working principle of vapour absorption refrigeration system;
I will share with you the working principle of the vapour absorption refrigeration system in steps so that you understand every process that happens in the system to result in the cooling effect.
Step by step of how vapour absorption refrigeration system works;
Step 1; The liquid refrigerant in the evaporator absorbs heat from the medium that needs to be cooled and it states changes from liquid to gas.
Step 2; the vapour refrigerant from the evaporator is drawn to the absorber where it’s absorbed by the absorbent (weak solution) to form a strong solution.
The absorber maintains low pressure in the evaporator by sucking the vapour refrigerant out of the evaporator thus making it easier for the refrigerant to evaporate at low temperature.
This increases the efficiency of the refrigeration system.
The combination of the weak solution and the vapour refrigerant forms a strong solution that will be circulated in the refrigeration system.
Step 3; the strong solution will be pumped out of the absorber to the generator by a pump. The action of the pumping also increases the pressure of the strong solution.
Step 4; the strong solution is heated in the generator to drive off the vapour refrigerant from the strong solution thus making it a weak solution.
Since the pressure of the vapour refrigerant is high to that of the condenser, the vapour refrigerant from the strong solution will enter the condenser.
The suction action performed by the absorbent and the function of heating the strong solution performs the compression and discharge of the refrigerant vapour to the condenser.
Between the generator and absorber, a shell and a heat exchanger are introduced to enhance the heat transfer that is required for heating the strong solution in the generator.
The weak solution in the generator is left for recycling, it will flow back to the absorber to be reused.
The heating of the strong solution in the generator can be achieved by the use of hot water or steam.
Step 5; in the condenser, the vapour refrigerant driven off from the strong solution is cooled and it changes its phase from gas to liquid.
Due to the pressure difference between the condenser and the evaporator the liquid refrigerant flows to the evaporator via the pressure-reducing valve.
The pressure-reducing valve is used to decrease the pressure of the liquid refrigerant as it enters the evaporator.
The liquid refrigerant entering the evaporator has to be of low pressure to be able to evaporate under low temperature.
Once the liquid refrigerant is back in the evaporator the process is repeated.
This is all about the working principle of the vapour absorption refrigeration system.
If you have any questions about the working principle leave your comment.
Thanks for reading, see you in my next article.
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