Introduction to Heat Pumps

This house is heated by the heat pump system shown below.
Arrow showing QH flowing from the heat pump into the house.
This arrow shows that work must be supplied to drive the heat pump.
Arrow showing QC flowing from cold outside air into the heat pump.
Miniature process flow diagram of a heat pump cycle.
Outside Cold Air
The outside air is the cold reservoir for the household heat pump system
The primary difference between a

heat pump

and a

vapor-compression refrigerator

is that the objective is not to remove heat from the cold reservoir. The objective of a

heat pump

is to deliver heat to the hot reservoir: QH.
The range of operating temperatures for a household

heat pump

is very similar to the temperature range for a household refrigerator.
The hot reservoir (the air in your home) is typically at about 25°C and the cold reservoir (the outdoor air on a winter day) might be at -5°C.
It is not surprising that many of the same


are used for

heat pumps

and refrigerators, including



Heat pumps

also operate on the same cycle as the

vapor-compression refrigeration cycle

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Ch 10, Lesson D, Page 1 - Introduction to Heat Pumps