Heat Pumps for Cooling

Overview

Heat pumps can be used for both heating and cooling. In heating mode, they pump heat from the surroundings into a building; in cooling mode, they absorb heat inside a building and give it off to the outside.

In either mode, a heat pump requires an input of energy (usually electricity) for performing the work of 'pumping'. Most of this energy is used for compressing the refrigerant. The amount of energy required to drive a heat pump is expressed through its coefficient of performance (the ratio of heat transferred to work input). The higher the coefficient of performance, the more efficiently a heat pump runs. While heat pumps can reach coefficients of performance of 3.5 to 4 when in heating mode, they do not operate as efficiently when cooling.