Refrigeration and Psychrometrics Lab Fresh air at 2300 cfm, 41oC and 30% rh is mixed with recirculated air at 26oC and 60% rh. The mixed air stream temperature is 31oC. The mixed air stream is then cooled, dehumidified and reheated to 17oC and 40% rh.
The cooling is provided with a multi-stage vapor compression refrigeration system using R717 as the working fluid. The evaporator temperature is 10oC less than the air temperature leaving the cooling coil and the condenser temperature is 12oC higher than the fresh air temperature. The intermediate pressure is selected such that the temperature in the flash tank is the average of the evaporator and condenser saturation temperatures. Assume that the refrigeration system is ideal except for the compressor efficiencies, which are 75%.
Determine:
1. The cooling load, in kW.
2. The volume flow rate of condensate removed in the cooling coil, in L/min.
3. The heating load, in kW.
4. The three pressures for the two-stage vapor compression refrigeration cycle, in bar.
5. The total power input to the compressors, in kW.
6. The rate of heat rejection from the condenser, in kW.
7. The COP of the system.