Thermodynamic Calculations of Two-Stage Vapor Compression Refrigeration Cycle with Flash Chamber/Regenerative Intercooler
Author: Volodymyr Voloshchuk
Introduction In the event that a high COP of a refrigeration cycle is of greater importance compared to other factors, it is possible to significantly increase the COP of a basic cycle through the use of a multistage vapor compression cycle. This is especially true when the pressure ratio between the heat rejection and heat absorption pressures is large 5 or more. Multistaging involves one or more intermediate pressures between the heat rejection and heat absorption pressures, and a series of compressors operating between successive pressure intervals. Creation functions on properties and processes of working fluids > >
Vapor pressure on the saturated line as a function of temperature >
Liquid pressure on the saturated line as a function of temperature >
Liquid temperature on the saturated line as a function of pressure >
Vapor temperature on the saturated line as a function of pressure >
Liquid specific enthalpy on the saturated line as a function of temperature >
Vapor specific enthalpy on the saturated line as a function of temperature > Liquid specific enthalpy on the saturated line as a function of pressure >
Vapor specific enthalpy on the saturated line as a function of pressure >
Liquid specific entropy on the saturated line as a function of temperature >
Vapor specific entropy on the saturated line as a function of temperature >
Liquid specific entropy on the saturated line as a function of pressure >
Vapor specific entropy on the saturated line as a function of pressure >
Temperature as a function of pressure and specific entropy >
Temperature as a function of pressure and specific enthalpy >
Specific enthalpy as a function of pressure and temperature >
Specific entropy as a function of pressure and temperature >
>
Input Data Temperature of heat source > (3.1) Temperature of heat consumption > (3.2) Temperature difference in the evaporator > (3.3) Temperature difference in the condenser > (3.4) Isentropic efficiency of the compressor > (3.5) Pressure increase in compressor 1 > (3.6) Working fluid > (3.7)
Calculations Temperature of the working fluid at the evaporator outlet > (4.1) Pressure of the working fluid at the evaporator outlet > (4.2) Specific enthalpy of the working fluid at the evaporator outlet >
(4.3)
Specific entropy of the working fluid at the evaporator outlet >
(4.4)
Pressure of the working fluid at the flash intercooler outlet > (4.5) Pressure of the working fluid at the flash intercooler outlet > (4.6) Temperature of the working fluid at the flash intercooler outlet > (3.2)
> (4.7) Specific enthalpy of the working fluid at the flash intercooler outlet >
(4.8)
Specific enthalpy of the working fluid at the flash intercooler outlet >
(4.9)
Pressure of the working fluid at the evaporator intlet > (4.10) Specific enthalpy of the working fluid at the evaporator intlet >
(4.11)
Temperature of the working fluid at the evaporator intlet > (4.12) Specific enthalpy of saturated liquid of the working fluid at the evaporator inlet >
(4.13)
Quality of the working fluid at the evaporator intlet
> (4.14) Specific entropy of saturated liquid of the working fluid at the evaporator inlet >
(4.15)
Specific entropy of the working fluid at the evaporator inlet >
(4.16)
Specific entropy of the working fluid at the compressor 1 outlet after isentropic compression >
(4.17)
Temperature of the working fluid at the compressor 1 outlet after isentropic compression > (3.2)
> (4.7)
> (4.18) Specific enthalpy of the working fluid at the compressor 1 outlet after isentropic compression >
(4.19)
Enhtalpy change in the compressor after isentropic compression >
(4.20)
Enhtalpy change in the compressor 1 after actual compression
>
(4.21)
Specific enthalpy of the working fluid at the compressor 1 outlet after actual compression >
(4.22)
Specific enthalpy of the working fluid at the compressor 1 outlet after actual compression > (4.23) Specific entropy of the working fluid at the compressor 1 outlet after actual compression >
(4.24)
Pressure of the working fluid at the compressor 2 intlet > (4.25) Temperature of the working fluid at the compressor 2 intlet > (4.26) Specific enthalpy of the working fluid at the compressor 2 intlet >
(4.27)
Specific entropy of the working fluid at the compressor 2 intlet >
(4.28)
Temperature of the working fluid at the condenser outlet > (4.29) > (3.2)
> (4.7)
> (4.18)
(4.29) Pressure of the working fluid at the condenser outlet > (4.30) Specific enthalpy of the working fluid at the condenser outlet >
(4.31)
Specific entropy of the working fluid at the condenser outlet >
(4.32)
Pressure of the working fluid at the compressor 2 outlet > (4.33) Pressure increase in the compressor 2
> (4.34) Specific entropy of the working fluid at the compressor 2 outlet after isentropic compression >
(4.35)
Temperature of the working fluid at the compressor 2 outlet after isentropic compression > (4.36) Specific enthalpy of the working fluid at the compressor 2 outlet after isentropic compression >
(4.37)
Enhtalpy change in the compressor 2 after isentropic compression >
(4.38)
Enhtalpy change in the compressor 2 after actual compression
>
(4.39)
Specific enthalpy of the working fluid at the compressor 2 outlet after actual compression >
(4.40) > (3.2)
> (4.7)
> (4.18)
(4.29)
(4.40)
Specific enthalpy of the working fluid at the compressor 2 outlet after actual compression > (4.41) Specific entropy of the working fluid at the compressor 2 outlet after actual compression >
(4.42)
Specific enthalpy of the working fluid at the flash intercooler intlet >
(4.43)
Pressure of the working fluid at the flash intercooler intlet > (4.44) Temperature of the working fluid at the flash intercooler intlet > (4.45) Specific enthalpy of saturated liquid of the working fluid at the flash intercooler inlet >
(4.46)
Quality of the working fluid at the flash intercooler intlet
> (4.47) Specific entropy of saturated liquid of the working fluid at the flash intercooler inlet >
(4.48)
Specific entropy of the working fluid at the flash intercooler inlet >
(4.49)
Ratio of mass flow rates between the high pressure circuit and that of the low pressure circuit
> (4.50) Heat rejection in the condenser referred to 1 kg of refrigerant in the low pressure circuit >
(4.51) > (3.2)
> (4.7)
> (4.18)
(4.29)
(4.40)
(4.51)
Heat addition in the evaporator referred to 1 kg of refrigerant in the low pressure circuit >
(4.52)
The total work of compressors referred to 1 kg of the working fluid in the low pressure circuit >
(4.53)
Coefficent of performance of a refrigerator
> (4.54) Coefficent of performance of a heat pump
> (4.55)
Plot the Refrigeration Cycle on a P-h-T Chart > > > > > > > (3.2)
> (4.7)
> (4.18)
(4.29)
(4.40)
(4.51)
>