by Brent Sauser
I spent most of the 1970’s in college, mainly Arizona State University. I was a Sun Devil. I transferred from Orange County, California where the climate was pretty close to ideal. It got hot a couple days in the summer, but not oppressive. Then you have Tempe, Arizona, home to ASU . . . a suburb of Phoenix. Arizona redefined what “hot” really was. I learned to live like a cockroach and came out at night when the temperature would drop down to a cool 90 degrees F.
While I was in Architectural School at ASU I discovered that three feet below the sun baked surface was a constant 70 degrees soil temperature. No construction was taking advantage of this FREE resource for providing cooling. Instead, homes were equipped with swamp coolers or heat pumps to cool their structures . . . having to work with an average surface temperature of 100 degrees F or higher. I wondered how difficult would it be to take advantage of the constant, subsurface temperature and reduce the overall demand for cooling. Yet, today, 33 years later, the greater Phoenix area still ignores that great resource and continues to build “slab on grade” because . . . it’s cheaper to build that way.
That kind of wasteful, dollar-driven thinking needs to change. If more people were aware that the technology exists TODAY to help people take advantage of what Mother Earth is offering to us for FREE, they might be more willing to demand it from their builders. The return on investment is so reasonable that the option of installing a Ground Source Heat Pump should be a first consideration.
The principle behind how geothermal mechanical systems work is quite simple. Ground source heat pumps or geothermal heat pumps work by transporting heat from one area to another using a fluid called a refrigerant. Unlike refrigerators and air conditioners, however, ground source heat pumps are capable of both heating and cooling. Ground source heat pumps are reversible. They can pump heat into the earth or out of it by changing the direction the refrigerant flows in. A heat exchanger inside the house typically blows air past one of the pipes. If the exchanger is being used to heat the house, this pipe functions as the compressor, and the air picks up its heat as it flows past. If the pump is being used to cool the house, the air blows past the evaporator, which sucks heat out of the air and cools the house. The other pipe moves heat into and out of the ground in a variety of ways. A direct exchange heat pump is the most direct and efficient way heat is moved. The pipe runs directly under ground. Because the ground stays at a relatively constant temperature, the heat exchanger can efficiently pump heat into the ground to cool a building on warm days, then pump it out of the ground to warm the building back up when the weather turns cold.
For further information regarding geothermal heat pumps or ground source heat pumps please click on the links below.