Question

An apple farmer wants to build a refrigerated processing plant for his apples. The processing plant will wash, cool, and sort the apples. To maximize the apple life the apples are cooled to 33°F prior to shipping. The average maximum temperature outside the building is 90°F. The average temperature of the harvested apples is 85°F. He will process and ship, on average, 600 bushels per day. The heat transfer through the floor, ceiling, and walls requires an additional 50 tons of refrigeration. Design a refrigeration unit for the building. The refrigerant is R134A.

Using an multistage compression with regenerative cooling of the refrigerant. The pressure increase for both the first stage and second stage of compression are the same

a) Define the state points of the cycle.

b) Evaluate the cooling load and the energy transferred to the environment. [BTU/sec]

c) Evaluate the mass flow rate of the refrigerant. [lbm/sec]

d) Evaluate the size of the compressor motor [hp].

e) Evaluate the COP of the refrigeration unit.

Answer 1