Experiment 10Energy Balance in

Refrigeration Cycle

Ideal Refrigeration Cycle

• 1-2 Isentropic compression in a compressor• 2-3 Constant-pressure heat rejection in a condenser• 3-4 Throttling in an expansion device• 4-1 Constant-pressure heat absorption in an evaporator

4. Evaporator

1. Compressor

2. Condenser

3. Expansion valve

Set-Up

Types of Expansion Devices

Thermostatic Expansion Valve

Hand Expansion Valve

Thermostatic Expansion Valve1. The pressure in

remote bulb open valve

2. The evaporator pressure close valve

3. Superheat spring pressure close valve

Data to recordOutlet Pressure of Compressor PH

Inlet Pressure of Compressor PL

Channel 106 Discharge Temperature of Compressor T6

Channel 107 Suction Temperature of Compressor T7

Mass Flow Rate of refrigerant

Voltage of the Compressor V

Current of the Compressor I

2 1

Overall Efficiency:( )Energy_Rate_of_Refrigerant

Electrical_ Power_ Inputa

compressorm h hV I

2 1isentropic

2 1

1

2a

2s

Isentropic Efficiency:Isentropic Compressor Work

Actual Compressor Work:

Actual enthalpy at compressor inleth Actual enthalpy at compressor outleth Isentropic

s s

a a

w h hw h h

whereh

enthalpy at compressor outlet

Efficiency