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Solved: The coefficient of performance K = H/P is a
Chapter 20, Problem 8E(choose chapter or problem)
Problem 8E
The coefficient of performance K = H/P is a dimensionless quantity. Its value is independent of the units used for H and P, as long as the same units, such as watts, are used for both quantities. However, it is common practice to express H in Btu/h and P in watts. When these mixed units are used, the ratio H/P is called the energy efficiency ratio (EER). If a room air conditioner has K = 3.0, what is its EER?
Questions & Answers
QUESTION:
Problem 8E
The coefficient of performance K = H/P is a dimensionless quantity. Its value is independent of the units used for H and P, as long as the same units, such as watts, are used for both quantities. However, it is common practice to express H in Btu/h and P in watts. When these mixed units are used, the ratio H/P is called the energy efficiency ratio (EER). If a room air conditioner has K = 3.0, what is its EER?
ANSWER:Solution 8E
Step 1 of 4:
The refrigerator or air conditioner operation can be consider as the reverse operating heat engine. As heat engine takes heat from the hot body and transfers the heat into colder object. Whereas a refrigerator does the reverse process; that is, it takes heat from the cooler place(inside refrigerator) and gives it off to a warmer place(outside the refrigerator).
That is, a heat engine will do a net output mechanical work whereas the refrigerator or air conditioner requires a net input mechanical work.