Various Processes of Ericsson Cycle
The Ericsson cycle comprises of two isothermal and two constant pressure (isobaric) processes. The addition of heat takes place during constant pressure as well as isothermal processes. Here are the various processes of Ericsson cycle when applied to the piston and cylinder engine. Please refer to P-V diagram given at the bottom:
1) Isothermal expansion and heat addition process 1-2: During this process the air, which acts as a working fluid, is heated from the externally added heat. The heat of the air increases at constant temperature T1 and it expands. It is during this process that the work is obtained from the engine.
2) Constant pressure or isobaric heat rejection process 2-3: The air is then passed through the regenerator, where its temperature reduces to T3 at constant pressure. The heat absorbed by the regenerator is used for heating in the next part of the cycle. The air after passing through the regenerator is released as the exhaust gas.
3) Isothermal compression process 3-4: During this process the air drawn into the engine is compressed at constant temperature, by applying an intercooler. The pressurized air is then drawn into the air storage tank.
4) Constant pressure or isobaric heat absorption process 4-1: The compressed air at high pressure passes through the regenerator and absorbs the previously stored heat. It then flows to the piston and cylinder where it gets expanded and produces work during process 1-2. Thus the cycle keeps on repeating.