Question

In a heat pump, heat from the outdoors at –5C is transferred to a room at 17C, energy
being supplied by an electric motor. How many joules of heat will be delivered to the room for
each joule of electric energy consumed, ideally?

Answer 1

Answer :-

From the conservation of energy:

W+Q_l=Q_hW+Q  

l

​  

=Q  

h

​  

 

Q_h=(Q_h-W)\frac{T_h}{T_l}Q  

h

​  

=(Q  

h

​  

−W)  

T  

l

​  

 

T  

h

​  

 

​  

 

Q_h=(Q_h-1)\frac{290.15}{268.15}Q  

h

​  

=(Q  

h

​  

−1)  

268.15

290.15

​  

 

Q_h=13\ JQ  

h

​  

=13 J