Heating is heating, right? Not quite. Geothermal systems operate differently than fossil fuel-burning systems, and understanding the differences can help you get the most out of your geothermal system.
We all learned about heat transfer at a young age when our mother slapped our had when we reached for the stove. We were scolded, but protected from a very rapid source of heat transfer that would have left us with a nasty burn. Heating systems that use an open flame are not much different. The flame is burning the fuel flowing into the system at a regulated rate and creating a large amount of heat. Most homes in the US have forced air ducts or hot water pipes to then deliver that heat around the home. The goal of this system is to create as much of the heat from the centralized fossil-fuel burning flame and then transfer that heat to the air around the rest of the home in short bursts; then shut it off. When temperature in the home dips down low enough, the furnace kicks back on to heat up the home again.
When consumers want to save energy with this type of system, they can use a programmable thermostat to keep the system off for longer periods of time when they are not home. This causes the home to cool down to a lower temperature, but then requires the furnace to “catch up” when the homeowner returns and wants the temperature to come back up again.
Geothermal is more the coals in the fire that stay warm long after the flame has gone out. The goal of a geothermal system is to maintain a more constant temperature by delivering a lower temperature heat over a longer period of time. By extracting the heat from the ground more slowly, the soil directly around the loop is warmed up again by heat transfer from the soil farther away from the loop. We discussed potential problems with freezing in another post, but an over-sized heat pump or under-sized loop field can extract too much heat too quickly a freeze the ground around the loop field.
When the ground has time to recover, the system is able to better utilize the heat stored in the ground in an even fashion. This is why loop placement and spacing is important. You would not want to have a loop field where the loops are close to each other or overlapping. The Geo Guy has a more detailed article on why horizontal “slinky” loop fields are prone to this issue.
Geothermal is the world’s most efficient heating source and once you understand how the system works, you installation will be much more effective.
NexGen Energy’s self-driving loop technology is allowing ground-source heating applications to be installed almost anywhere! Please visit our website or join the discussion on Facebook. You can also leave a comment on this post if you have any thoughts or questions.