Chapter 5, Problem 5.81P

Find out the COP of a Carnot heat pump operating between 6°C and 37°C.

A reversed Carnot cycle refrigerator maintains a temperature of -5°C. The ambient air temperature is 35°C. The heat gained by the refrigerator at a continuous rate is 2.5 kJ/s What is the power (in watt) required to pump this heat out continuously?

Room (A) contains only an air conditioner with 6 KW capacity that works 3 hours per dayRoom (B) contains only a refrigerator with 0.9 KW that works 20 hours per day .which of the two rooms would get higher electricity bill by the end of day

An air conditioner with COP~2.8 cools a well-sealed house from 35°C to 22°C in 10 min. Please determine the power consumption of the air conditioner. Assume the entire mass of air within the house is equivalent to 800 kg, and specific heats at 300K can be used. Also plot the schematic of the air conditioner with heat reservoirs, all heat transfers and work transfer.

What is the highest COP that a refrigerator operating between temperature levels TL and TH can have?

A Carnot heat pump works between 27° C and 327°C. What will be its COP?

Problem 2- Refrigeration After returning from the store you place 4 bottles of water, 3 kg each, in the refrigerator. The water is initially at 25 °C and needs to be cooled to 10 °C. The refrigerator has a COP of 1.8 and a power input of 500 W. How long will it take for the refrigerator to cool the water? Is your calculation realistic? Explain.

A dairy-barn requires a cooler for milk and hot water for washing. A combination unit states that it combines these two functions for about the same cost as just running refrigeration for separate units by using the waste heat from refrigeration to heat the water. This combination unit takes 15 kJ/s from a milk cooler at -2°C and discards heat through a condenser at 65°C to raise the temperature of water from 13 to 63°C. The conventional 2 unit set-up takes the same amount of heat from the same milk cooler at -2°C and discards heat through a condenser at 50°C; in addition, the same amount of water is heated electrically from 13 to 63°C. Estimate the total electric power requirements for the combination unit case and the conventional 2 unit case. Assume the actual work in both is 50% greater than required by Carnot refrigerators operating between the given temperatures.

A typical 200-m2 house can be cooled adequately by a 3.5-ton air conditioner whose COP is 4.0. Determine the rate of heat gain of the house when the air conditioner is running continuously to maintain a constant temperature in the house.