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//(10.2) Modify Example 10.1 to allow for temperature differences between the refrigerant and the warm and cold regions as follows. Saturated vapor enters the compressor at 10C. Saturated liquid leaves the condenser at a pressure of 9 bar. Determine for the modified vapor-compression refrigeration cycle (a) the compressor power, in kW, (b) the refrigeration capacity, in tons, (c) the coefficient of performance. Compare results with those of Example 10.1.
//solution
mdot = .08 //mass flow rate in kg/s
//analysis
//at the inlet to the compressor, the refrigerant is a saturated vapor at 10C, so from Table A-10,
h1 = 241.35 //in kj/kg
s1 = .9253 //in kj/kg.k
//Interpolating in Table A-12 gives
h2s = 272.39 //in kj/kg.k
//State 3 is a saturated liquid at 9 bar, so
h3 = 99.56 //in kj/kg
h4 = h3 //since The expansion through the valve is a throttling process
//part(a)
Wcdot = mdot*(h2s-h1) //The compressor power input in KW
printf('the compressor power in kw is: %f',Wcdot)
//part(b)
Qindot = mdot*(h1-h4)*60/211 //refrigeration capacity in tons
printf('\nthe refrigeration capacity in tons is: %f',Qindot)
//part(c)
beta = (h1-h4)/(h2s-h1)
printf('\nthe coefficient of performance is: %f',beta)
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