A Primer On Heat Pumps

By Murray Anderson

As hard as it is to believe, even in the middle of winter, there's heat outside your home. Heat pumps allow you to take advantage of that natural heat and use it to warm your home. As an added bonus, heat pumps can also act like a central air conditioner by taking excess heat out of your home in summer, making it way more comfortable.  In general, heat pumps use two different types of technology to provide heating and cooling for your home. One design takes advantage of the heat in the air (air source heat pumps), while the other design utilizes heat in the ground or water (ground source heat pumps). Heat pumps are becoming more popular every year are getting a lot of consideration form homeowners interested in saving money on the energy bills while helping preserve the environment, so, here's an overview of how heat pumps work.

Air source heat pumps

• Air source heat pumps are the most common type of heat pump, probably because they are the easiest and least expensive design to install. Similar to an air conditioner, air source heat pumps consist of two distinct sections. An outdoor component containing a compressor, a coil, a fan and a reversing valve, while indoors, the second section contains a fan and indoor coil and a supplemental heating element. Plastic tubing containing a liquid refrigerant connects the two units.
• When the heat pump is in heating mode, the liquid refrigerant literally take warmth out of the outside air and carries it to the indoor coil where the blower moves filtered indoor air over the coil and out into your home. When in cooling mode, the unit operates similar to a central air conditioner. The warm air passes over the indoor coil and gives up its heat, which the refrigerant carries outside to be dissipated by the outdoor fan as it passes through the outdoor coil.
• As you've probably figured out, on particularly cold days there just isn't enough heat in the outside air to provide heat for your home. This is when the supplementary heating element turns on to provide the extra heat needed to make your home comfortable.
   

Ground source heat pumps

• Ground source or geothermal heat pumps use the earth or underground water as either the source of heat when warming your home or as a heat sink when in cooling mode. These systems consist of a series of pipes buried in the ground. In warming mode, an ethanol solution is circulated through pipes and acts as a heating conductor, picking up heat from the ground or water and carries it back into your home. Since the ground below the frost line remains at a relatively constant temperature all year round (45 to 70 degrees Fahrenheit depending on your location), it provides a ready source of heat even in the dead of winter.
• Inside the house the warmed water runs through an air handler box consisting of a blower/fan and an air filter where it give up its heat. The blower distributes the heat directly through your home's existing air distribution system. 
   

Murray Anderson is an experienced freelance writer over 500 articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com. He can be contacted at murand@lycos.com.