Problem $4-2.$ An ideal vapor$-$compression cycle uses Refrigerant $134$a as the working fluid and is designed to operate as an air source heat pump for the purpose of heating a residence to $\backslash (25^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$ The space heating requirement is $150$ kW when the outdoor temperature is $\backslash (0^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$ Select appropriate operating pressures of the evaporator and the condenser then calculate:

a$)$ the mass flow of the refrigerant required to satisfy the heating requirement,

b$)$ the coefficient of performance of the cycle,

c$)$ the rate of exergy destroyed for the cycle, and

d$)$ briefly discuss the effect of the operating pressures on the COP.