THERMODYNAMICS PROBLEM PLEASE HELP! Len Mattioli, more commonly known as \"Crazy
ID: 1431611 • Letter: T
Question
THERMODYNAMICS PROBLEM PLEASE HELP!
Len Mattioli, more commonly known as "Crazy TV Lenny," opens a new appliance store, but with an environmental twist. He offers you a great deal on one of his new Carnot Heat Pumps (a knock-off of the mainstream brand Carrier.) You ask him about their performance, and he tells you that on day when it is -4 degree C outside, you can pump 15 kW into your house at 20 degree C. What is the COP of this Carnot heat pump? How much work is necessary to move 15 kW? How much heat is extracted from the cold outside air? Does this heat pump comply with the Second Law of Thermodynamics? Crazy TV Lenny acknowledges your Second Law expertise and shows you a more realistic and slightly less expensive heat pump (albeit, imported from Entropia). He tells you the COP of this heat pump is a modest 8. How much work is necessary to move 15 kW? How much heat is extracted from the cold outside air? Does this heat pump comply with the Second Law of Thermodynamics?Explanation / Answer
a) COP of cycle = Tc/(Th - Tc)
= 269.15/(293.15-269.15)
= 11.21
b) work necessary = 15/11.21
= 1.338 KJ/sec
c) heat extacted = 15 - 1.338
= 13.662 KJ/sec
d) Yes, it comply with second law of thermodynamics .
e) work necessary = 15/8
= 1.875 KJ/sec
f) Heat extracted = 15 - 1.875
= 13.125 KJ/sec
g) No, it does not comply second law of thermodynamics .
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