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Heat Pumps

 

Heat Pump Systems

For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners. Like your refrigerator, heat pumps use electricity to move heat from a cool space into a warm, making the cool space cooler and the warm space warmer. During the heating season, heat pumps move heat from the cool outdoors into your warm house; during the cooling season, heat pumps move heat from your cool house into the warm outdoors. Because they move heat rather than generate heat, heat pumps can provide up to 4 times the amount of energy they consume.

The most common type of heat pump is the air-source heat pump, which transfers heat between your house and the outside air. If you heat with electricity, a heat pump can trim the amount of electricity you use for heating by as much as 30%–40%. High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. However, the efficiency of most air-source heat pumps as a heat source drops dramatically at low temperatures, generally making them unsuitable for cold climates, although there are systems that can overcome that problem.

For homes without ducts, air-source heat pumps are also available in a ductless version called a mini-split heat pump.

HEAT PUMP– Unlike a furnace, a heat pump doesn’t burn fuel to make heat. It simply uses electricity to move heat from one place to another. A heat pump is an energy efficient way to cool your home in the summer and heat it in the winter.

 

 

How does a heat pump work?

A heat pump is essentially an air conditioner that can also run in reverse. Both rely on the fact that a liquid absorbs heat as it is vaporized into a gas and that a gas releases heat as it condenses into a liquid. When in heating mode, a substance called a refrigerant will be compressed by the main component in a heat pump, the compressor. As it is compressed, it will release heat as it is condensed from a gas to a liquid.

The heated liquid will then be sent through a coil inside your home, where it will gradually cool down as it releases its heat into the ductwork or hot water pipes of your home’s heating system.  The liquid will then be sent through an expansion valve, where is will be reduced in pressure as it enters a wider pipe. The liquid will then enter the outdoor coil, where it will absorb heat as it boils into a gas.

When in cooling mode in the summer, the cycle is reversed so that heat is transferred from the indoors to the outdoors.

A typical Energy Star-labeled heat pump can produce heat at efficiencies of around 450% at outdoor temperatures of 20C (78F), which gradually drops down to about 250% at freezing.