Thermodynamics: Vapor Compression Refrigeration that is Adiabatic?

[Sara1]

Consider a heat pump works on the vapor-compression refrigeration cycle with 0.2 kg/s of refrigerant-134a as the working fluid. The cycle is used to maintain a house at 26oC while absorbing heat from the outdoors at 3oC. R-134a enters the compressor at 200 kPa as a saturated vapor and leaves at 900 kPa, 50oC. The refrigerant leaves the condenser as a saturated liquid. Assuming the four devices to be well-insulated:

I need to find COP, but in order for that i need QH, which i can't have because all the devices are insulated. How do i proceed?

 

[RTW69]

COP (heating)=Q-hot/W-net,in

COP (heating)=M-dot * (h₂-h₄)/m-dot * (h₂-h₁)

Pt 1: 200 kPa,3 C
Pt 2: 900 KPa,50 C
Pt 4: 900 KPa, 26 C

See if that works

 

[RTW69]

Correction

Pt 1:200 kPa, sat. Vapor, -9 C

Pt 2: 900 kPa, 50 C

Pt 4: 900 kPa, sat. liquid, 35.4 C

Find enthalpy' s for various points, use equation for COP-heat

 

[Sara1]

Thank you