What is bell coleman cycle?
- Bell coleman air refrigeration cycle is reverse brayton cycle which consists of the two isentropic processes and two constant pressure (Isobaric) processes which is used to absorb heat from the low-temperature cabin and reject it to the high-temperature cabin.
- This cycle is used for the both heating and cooling purpose and uses air as an refrigerant (working fluid).
Bell coleman cycle diagram:
Construction:
This refrigeration cycle consists of the following parts:-
- Cooler
- Air expander
- Cold chamber/Refrigerator
- Compressor
1) Cooler:- It is a cooling device that is used to remove the heat from high pressure and temperature compressed air with the help of a cooling medium.
2) Air expander:- It is an expansion device that converts the high-pressure air into low-pressure air and the work produced during expansion is used to drive the compressor.
3) Cold chamber:- It is space which to make cooled, When cold air passes through the cold chamber, it takes the heat from the cold chamber.
4) Compressor:- Compressor compresses the air that comes from the cold chamber to high pressure.
Working of bell coleman cycle:
1) Compressor takes the air from the cold chamber and compresses the to high pressure.
2) The high pressure and high-temperature air from the compressor flow to the cooler. In a cooler, heat removes from the air with the help of a cooling medium which may be water.
3) After cooler low temperature and high-pressure air passes through the expander. The expander expands air to low pressure & produces work that is used for the driven compressor.
4) The low pressure & low-temperature air from the expander flow through the cold chamber, where air absorbs the heat from the cold chamber (which to be cooled) & provides a cooling effect.
5) After absorbing heat from the cold chamber, air again flows to the compressor.
In such a way, the cycle continues again & again.
Bell coleman cycle Pv & Ts diagram:
This cycle consists of two isentropic processes and two isobaric (constant pressure) processes.
The four Processes in the Bell coleman cycle are as follows:-
- 1-2:- Isentropic compression from P1 to P2.
- 2-3:- Constant pressure heat rejection.
- 3-4:- Isentropic expansion from P3 to P4.
- 4-1:- Constant pressure heat addition process.
Bell coleman cycle advantages:
The advantages of the bell coleman cycle are as follows:-
- Simple in construction.
- Air is used as refrigerant which is cheaply available and also non-toxic.
- No harmful, if any leakage.
- Low maintenance cost.
Bell coleman cycle disadvantages:
The disadvantages of the bell coleman cycle are as follows:-
- The system is bulkier hence weight per ton of refrigeration is higher.
- High operation cost.
- Less coefficient of performance (COP) as compared to other systems.
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