Question

1.3 127 5.3 3.(10 pts) A cold storage room (10 m x 10 m x 10 m) is being maintained at 2 °C using a vapor compression refrigeration system that uses R-134a. The evaporator and condenser temperatures are -20 and 40°C, respectively. The walls and ceiling of the storage room is constructed of 15 cm thick concrete (thermal conductivity-1.37 WIm K]) and 4.3 cm thick insulation (thermal conductivity-0.04 W/[m K). The outside insulation surface temperature of the walls (or ceiling) is 35°C, and the inside concrete walls (or ceiling) temperature is 5°C. Ignore heat transfer from the floor. Determine: (a) (5 pts) The cooling load required. b) (5 pts) The mass flow rate of refrigerant (If you don't know how to calculate the cooling load, you can a the compressor efficiency is 85%, and rate of heat removed by condenser. e the cooling load is 10 kW), the compressor power requirement assuming 296 Words English (US) EW Focus MacBook Pro 2 3 4 5 6

Answer 1

SoLution Given that, A cold stahage Room is being maintained a 2 maintane K, K S C JS C 13 L2 Lt Lw 1.37CT,-5) o 043 0 15 Ti = 7.77°C 0. 0 h(5-2) o 043 Q84424x 500 (5-2) 2 665 kw Asgsitaka at evapesahos Assuming sa .Qout 40 C 3 Qin

E Cod mRーは665 386.S54 256.41 at S3s= 1.14132 kJ /kg K P = 10-174 n's = 429,635 kJ/kg σ85_. 429.035-386 , Ss 3-3 8.ss 0 0473 C436-S3 386- Ss4) 冫4,863 kW QR 0,0973 C436. 53-256-41) 30,-- ,7i53 KW