VAPOR COMPRESSION REFRIGERATION SYSTEM WITH HEAT EXCHANGER

Описание: PROBLEMS:
A simple vapor-compression cycle develops 13 tons of refrigeration. Using ammonia as refrigerant and operating at a condensing temperature of 24 C and evaporating temperature of -18 C and assuming that the compression are isentropic and that the gas leaving the condenser is saturated, find the following:
Draw the ph diagram
Refrigerating effect in kJ/kg
Circulation rate of refrigerant in kg/min
Power requirement
Volume flow in cubic meter/min
Coefficient of performance
Power per ton

A simple saturated refrigeration cycle using R-134a as refrigerant operates between evaporator temperature of -10ºC and condenser temperature of 35ºC. If a heat exchanger is installed and would superheat suction vapor from -10ºC to 15ºC, calculate the COP.

Saturated vapor R-12 refrigerant at 219.12 kPa leaves the evaporator and enters the compressor at -5°C. The refrigerant leaves the condenser as saturated liquid at 25°C and enters the expansion valve at 22°C. Heat rejected from the condenser amount to 74 kW. The work to the compressor is 55.5 kJ/kg while the heat lost from the compressor is 4.2 kJ/kg. If 1.15 kJ/kg are lost in the piping between the compressor and condenser, calculate the refrigeration capacity in tons.