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 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.
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