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Solved: Arctic explorers are unsure if they can use a 5-kW
Chapter 5, Problem 151EUP(choose chapter or problem)
Problem 151EUP
Arctic explorers are unsure if they can use a 5-kW motor-driven heat pump to stay warm. It should keep their shelter at 60 F; the shelter loses energy at a rate of 0.3 Btu/s per degree difference from the colder ambient. The heat pump has a COP that is 50% that of a Carnot heat pump. If the ambient temperature can fall to −10 F at night, would you recommend this heat pump to the explorers?
Questions & Answers
QUESTION:
Problem 151EUP
Arctic explorers are unsure if they can use a 5-kW motor-driven heat pump to stay warm. It should keep their shelter at 60 F; the shelter loses energy at a rate of 0.3 Btu/s per degree difference from the colder ambient. The heat pump has a COP that is 50% that of a Carnot heat pump. If the ambient temperature can fall to −10 F at night, would you recommend this heat pump to the explorers?
ANSWER:
Solution 151 EUP:
Step 1 of 2:-
Here we have to explain that, if the ambient temperature falls to , whether to recommend this heat pump to the explorers or not.
The motor used is 5 kw.
The shelter temperature should be 60 F.
The heat transfer rate from the shelter is 0.3 Btu/s per degree difference from the colder one.
The COP is 50% of the carnot engine.
So,
.
Which is 50 % of the carnot COP. so,
.