Geothermal heating and cooling
An ecologically and financially efficient option.
Thu, Nov 11, 2010 at 05:02 PM
Geothermal heating and cooling systems are a blend of the old and the new. Blending basic earth science with systems that don’t look much different than you are accustomed to seeing, geothermal heating and cooling systems provide a wide range of benefits.
It doesn’t matter what type of building, where it is located, how old it is, or what the building is made of, geothermal heating and cooling can be installed. [See related: Eco-friendly heating]
An excellent example is the retrofitting of a Mason’s Lodge in Turners Falls, Mass. (Harmony Lodge). The fact that it was built in 1873 and had three previous heating systems was not even a minor deterrent for Rich Baker, owner of GeoSun Design in Amherst, Mass.
According to Mason member Nick Prokowitch, when their previous system began to fail (an oil boiler), they had a hard time finding anyone who could repair the boiler properly. “It was difficult to maintain due to the age,” said Prokowitch of the boiler, which was installed in the 1970s. He added that besides problems with properly maintaining the boiler’s water levels, sometimes it would blow off steam into the lodge’s basement. “It was wet down there all the time and it would set off smoke alarms,” he said.
Prokowitch was given the task of finding a new system for the lodge. After Prokowitch got various bids for electric, oil and gas, he decided to go a step further and check out the possibility of a geothermal system and was sold immediately. “Realistically, oil prices aren’t going to come down. The (Mason) members were 100 percent for this system,” he said. “And everybody liked the idea of consistent heat at 72 degrees 24/7. Before, we would keep the thermostat 50 degrees if the rooms were empty,” said Prokowitch. “We would just put the heat on if someone where there.” He added that the members are “especially happy that they can now have air-conditioning as well as heat.”
How do geothermal heating and cooling systems work?
Baker explained that once the size and scope of a project is determined, as well as the heat load needed for each room in the building, water solution-filled pipes are placed at specific spacing just below the earth. Ground temperatures remain constant at 45 to 70 degrees F year-round.
The water absorbs the temperature of the earth, and then runs into a heat exchanger, which gives off the heat to a gas (eco-friendly) refrigerant. The gas is brought up to temperature and goes through a compressor, which also raises the temperature. The gas goes back through a second heat exchange unit giving off heat to air which then circulates through your ducts. “It’s all math,” said Baker.
Baker said that an important part of his design process is to make sure that the pipes are placed so that the energy taken from the earth is easily replenished. If pipes are not placed correctly, the system cannot function properly (i.e. for example the land area can’t replenish the temperature quickly enough). In summer the process is reversed. The system extracts heat from the interior air and transfers it to the ground by way of the ground loop piping.
Baker said there are a lot of different systems on the market and that he uses about a dozen different company’s products. “I’m not married to any one of them. It really depends on the project,” he said. Systems can be horizontal or vertical depending on the area the system is being placed.
What is the cost effectiveness?
Prokowitch determined that a new system for the lodge would cost between $15,000 and $22,000. While the geothermal system being installed will cost in the range of $30,000, with a 30 percent tax credit and an annual energy savings of 40 to 70 percent, the system will cost about the same as a traditional system and pay for itself over time. *Note: Always check current federal and state energy tax incentives as they change over time. Baker added that a geothermal heating and cooling system can save over $1,400 a year over oil or electric heating.
What are some of the other benefits of geothermal heating and cooling?
Geothermal is renewable and environmentally friendly, with no need for fossil fuels or generation of pollution. The system is a closed loop and does not take up any ground water. You get heating and cooling with one system, and a greater degree of consistent comfort. Depending on your building you can have a singular control panel. And again, you can put a system in virtually any building. The only energy used is the electricity for circulatory pumps to move the water through the system. Lastly, geothermal heating and cooling systems are quiet.
What should I look for when hiring a designer?
The important word here is designer. There are some whose entire business is geothermal heating and cooling, and some professionals are HVAC installers who install with a designers plan. Lastly, there are installers who may know plenty about traditional systems, but may not be fully qualified to install a geothermal system.
Baker said the first thing to look for in hiring is if your professional has a International Ground Source Heat Pump Association (IGSHPA) certification. Baker said to ask if they do an “actual” heat load calculation, or “rule-of-thumb.” “You want to know the heat load requirements of each individual room,” said Baker.
The professional must be able to do soil analysis, an operating cost analysis, and side-by-side cost analysis with other systems.