When Does a Heat Pump Become Ineffective Based on COP?

AI Thread Summary
The discussion centers on determining the outside temperature at which a heat pump becomes ineffective based on its coefficient of performance (C.O.P.), which is 17% of the maximum achievable. The relevant formula for C.O.P. is provided, and participants express a need for guidance on how to approach the problem without the maximum C.O.P. value. It is suggested that the maximum C.O.P. can be multiplied by 0.17 to find the operational efficiency. The conversation emphasizes understanding the relationship between outside temperature and heating efficiency for effective heat pump operation.
rvaafrica
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1. You have a heat pump which has a coefficient of performance (C.O.P.) that is 17% of the maximum achievable. You want to heat your house to 20◦C. At what outside temperature does the heat pump become not useful?



2. C.O.P. = 1/(T1/T0 - 1)
T1= Temperature of the outside
T0 = Temperature of the house



3. Hi. Basically I am NOT looking for someone to give me an answer. I would just like some help on how to approach this problem. I know how to solve for T1 if they give the maximum C.O.P but I am stuck on how to complete this problem since the max. C.O.P is not given. Any help would be greatly appreciated.
 
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rvaafrica said:
1. You have a heat pump which has a coefficient of performance (C.O.P.) that is 17% of the maximum achievable. You want to heat your house to 20◦C. At what outside temperature does the heat pump become not useful?
2. C.O.P. = 1/(T1/T0 - 1)
T1= Temperature of the outside
T0 = Temperature of the house
3. Hi. Basically I am NOT looking for someone to give me an answer. I would just like some help on how to approach this problem. I know how to solve for T1 if they give the maximum C.O.P but I am stuck on how to complete this problem since the max. C.O.P is not given. Any help would be greatly appreciated.
The equation for COP gives you the maximum (Carnot) COP. (Note: the denominator should be (1 - T1/T0)). Just multiply the maximum COP by .17

What is the value of COP at which the heat pump stops being useful?

AM
 

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