Heat Pumps

Heat Pumps

My home system doesn’t seem to work quite right.

A heat pump is a device that moves heat from one location to another location using a mechanical means. There are two common types of heat pumps: air-source heat pumps and ground-source (geothermal) heat pumps, with variations on both. Both can keep your home warm in the winter and cool in the summer. An air-source heat pump pulls its heat indoors from the outdoor air in the winter and from the indoor air in the summer. A geothermal heat pump extracts heat from the indoor air when it’s hot outside, but when it’s cold outside, it draws heat into a home from the ground.

A heat pump’s refrigeration system consists of a compressor, and two coils made of copper tubing, which are surrounded by aluminum fins to aid heat transfer. The coils look much like the radiator in your car. Like in a refrigerator or air-conditioner, refrigerant flows continuously through pipes, back and forth from the outdoor coils. In the heating mode, liquid refrigerant extracts heat from the outside coils and air, and moves it inside as it evaporates into a gas. The indoor coils transfer heat from the refrigerant as it condenses back into a liquid. A reversing valve, near the compressor, can change the direction of the refrigerant flow for cooling, as well as, for defrosting the outdoor coils in winter.

Air-Source Heat Pumps

An air-source heat pump can provide efficient heating and cooling for your home, especially if you live in a warm climate. When properly installed, an air-source heat pump can deliver one-and-a-half to three times more heat energy to a home compared to the electrical energy it consumes. This is possible because a heat pump moves heat rather than converting it from a fuel, by exploiting the physical properties of the refrigerant.

Ground-Source Heat Pumps

A ground-source heat pump system is a central heating and/or air conditioning system that actively pumps heat to or from the shallow ground. It uses the earth as either a source of heat in the winter or as a coolant in the summer. This design takes advantage of moderate temperatures in the shallow ground to boost efficiency and reduce operational costs.

But unlike an air-source heat pump a ground-source heat pump exchanges heat with the ground. This is usually more energy-efficient because underground temperatures are relatively stable through the year. Like a cave, the shallow ground temperature is warmer than the air above during the winter and cooler than the air in the summer. A ground-source heat pump extracts that ground heat in the winter (heating) and exhausts heat back into the ground in the summer (cooling).