A refrigeration unit operates on the ideal vapor

Chapter 11, Problem 110P

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11-110 A refrigeration unit operates on the ideal vapor compression refrigeration cycle and uses refrigerant-22 as the working fluid. The operating conditions for this unit are evaporator saturation temperature of \(-5^{\circ} \mathrm{C}\) and the condenser saturation temperature of \(45^{\circ} \mathrm{C}\). Selected data for refrigerant- 22 are provided in the table below.  

45	1728	101

For R-22 at  and

 and  Also, take

\(c_{p, \text { air }}=1.005 \mathrm{~kJ} / \mathrm{kg} \cdot K\)

(a) Sketch the hardware and the \(T-s\) diagram for this heat pump application.

(b) Determine the COP for this refrigeration unit.

(c) The evaporator of this unit is located inside the air handler of the building. The air flowing through the air handler enters the air handler at \(27^{\circ} \mathrm{C}\) and is limited to a \(20^{\circ} \mathrm{C}\) temperature drop. Determine the ratio of volume flow rate of air entering the air handler \(\left(m_{\text {air }}^{3} / m i n\right)\) to mass flow rate of \(R-22\left(k g_{R-22} / s\right)\) through the air handler, in \(\left(m_{\text {air }}^{3} / m i n\right) /\left(k g_{R-22} / s\right)\). Assume the air pressure is .

Equation Transcription:

   

 

     

     

   

     

     

 

Text Transcription:

-5°C    

 45°C

cp, air = 1.005 kJ/kgK      

T-s      

27°C    

20°C    

(m air 3/min)    

R-22(kgR-22/s)

(m air 3/min)/(kgR-22/s)