A heat pump moves heat from outside, where the temperature is 3°C, to inside a b
ID: 1421534 • Letter: A
Question
A heat pump moves heat from outside, where the temperature is 3°C, to inside a building, where the temperature is 22°C.
(a) What is the coefficient of performance of an ideal heat pump operating between these two temperatures?
(b) In each cycle, the heat pump removes 370·J of heat from the outside. How much work must be provided in each cycle?
(c) How much heat is dumped into the building in each cycle?
(d) Compared to this ideal heat pump, how much work would a real heat pump require to move the 370·J of heat from outside to inside? Choose one answer only.
a) more work
b) the same amount of work
c) less work
d) could be more, less, or the same work...depending on the heat pump
Explanation / Answer
here,
COP = T2/(T2-T1)
T2 = 22+273 = 295 K
T1 = 3+ 273 = 276 K
so
COP = (295/276) *100
COP = 106.88%
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part B :
b)Q out - workdone = Q in
Cop = (Q in ) /W
wrtting Q in interms of Q out and W w have
Cop = (Q out - work)/(work)
COP = (Qout/work) - 1
COP+1 = Qout/work
Work W = 370/1.06
W = 349.05 Joules
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c)
Q out - workdone = Q in
370- 349.05
Qout = 21 joules
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d. option a) more work