Question

Write an introduction about performance characteristics of heat pump Write clearly

Answer 1

INTRODUCTION

• A heat pump is a device that extracts thermal energy from a low-temperature source (such as the outside air or ground) and transfers it to a higher-temperature sink (such as the heated indoors of a building).
• For instance, a household refrigerator may be thought of as a heat pump. While cooling the food products, it takes thermal energy from them. The outside coil, on the other hand, transfers thermal energy to the ambient air. The food acts as the source, the air in the kitchen as the sink.
• Basic laws in thermodynamics recognize that work is not required to transfer heat from a high-temperature source to a lower-temperature sink (a simple conductive path would suffice), but it is required to transfer thermal energy from a low-temperature source to a higher-temperature sink.
• The shaft work per unit time, It is the input needed to operate the heat pump, while T_H is the rate of thermal energy transferred to the warmer environment, and T_C , is that taken from the colder environment. The case represented is that of heating the warmer indoors, at T_H while extracting thermal energy from the colder outdoors, at T_C.
• The desired output in this case of a heating mode is T_H. Hence, the coefficient of performance of the heat pump, in the heating mode, would be :

COP = Q_H /W =T_H/W =T_​​H/ T_H - T_C

Where - T_H is higher inside temperature

T_{​​​​​​C} is lower outside temperature

W= Q_{​​​​​​H} - Q_C = T_H - T_C

Q_H - higher heat rate

Q_{L -} lower heat rate

Hence, COP > 1.0.