Question

Problem 10.012 SI A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 2.6 bar, and saturated liquid exits the condenser at 12 bar. The isentropic compressor efficiency is 80%. The mass flow rate of refrigerant is 7 kg/min. Determine: (a) the compressor power, in kW. (b) the refrigeration capacity, in tons. (c) the coefficient of performance.

Answer 1

Answer:

a) 4.1 kw

b) 4.68 tons

c) 4.02

Explanation:

Saturated vapor enters compressor at ( p1 ) = 2.6 bar

Saturated liquid exits the condenser at ( p2 ) = 12 bar

Isentropic compressor efficiency = 80%

Mass flow rate = 7 kg/min

A) Determine compressor power in KW

compressor power = m ( h2 - h1 )

                                = 7 / 60 ( 283.71 - 248.545 )

                                = 4.1 kw

B) Determine refrigeration capacity in tons = m ( h1 - h4 )

                                                                       = 7/60 ( 248.545 - 107.34 )

                                                                       = 16.47 kw = 4.68 tons

C) coefficient of performance ( COP )

= Refrigeration capacity / compressor power

= 16.47 / 4.1 = 4.02

Attached below is the beginning part of the solution