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Geothermal heating and cooling

A geothermal heat pump is not much different than a standard air conditioner when in cooling mode. With a standard ac, the heat is rejected to the air (this is why you feel heat out of the top of your condensing unit). Geothermal works the same, except the heat is rejected to the earth through ground loops. In heating mode, the refrigeration cycle is reversed, and heat is extracted from the earth much like an air source heat pump extracts heat from air. The reason geothermal is more efficient, is that the ground is much colder than the air during the summer and the ground is warmer than the air in the winter.

Oops, after reading your post again, my post doesn't look like what you are looking for.


  • Dennis Wilson
    Dennis Wilson Member Posts: 1
    Geothermal heating and cooling

    We're thinking of installing a geothermal heat pump to heat our hydronic radiant floors and have a fair understanding of how the system works. Our problem is figuring out how the system is reversed in the summer to cool the house. Specifically we would like to know what mechanics are used to gather excess heat and delivered to the geothermal system and then how cool air is produced and by what means delivered to the air conditioning ducts. We've looked extensively on the Web and can't find a source that provides detailed enough illustrations to explain how the air conditioning part of the system works.
  • Gary Hayden
    Gary Hayden Member Posts: 3

  • Jack
    Jack Member Posts: 1,047
    I used to...

    run the loop to the swimming pool and heat (reject the house heat) the pool in the summer. Don't cover the pool at night and the heat will typically radiate to atmosphere. This was in the late 70's and in N CA so the degree days were about a push. We'd use a glazed solar system to heat the pool, with a good insulated pool cover and use the pool as the water source. You could also put a small cooling tower on the system to reject heat. Lots of options, have a ball!
  • Warren_3
    Warren_3 Member Posts: 3
    How to heat radiant with GEO

    The easiest way is to dedicate unit(s) for radiant flooring only. This can be done with units that are "water to water" vs. "water to air" Another easy way is to purchase units that have the domestic water heating attachment. Most manufacturers such as Water Furnace & FHP have this option. Set up this to heat the radiant, it is most effective when systems are in the heating mode ( when you would want the radiant) & does not effect the cooling. There are several other ways to set it up, these are the simplest. Further there is A LOT of piping & control work once you decide how you wish to heat the radiant.
  • Mike Dunn
    Mike Dunn Member Posts: 189
  • Craig R Bergman
    Craig R Bergman Member Posts: 101
    You are mistaken

    Domestic water heating, or desuperheater, is the most effective in the cooling mode. The desuperheater is not used to produce hot water for heating, it only produces hot water when there is a call for heating or cooling.


    Radiant and Geo work very well together. Max water temp is 120* so you must design your radiant system to that number.
    We use reversible, water to water heat pumps coupled with a buffer tank. In the heating mode, Hot water is first sent to the buffer for storage and use by the radiant system. In the cooling mode, Cold water is first sent to an air coil then to the buffer for storage. I've attached the piping layout we use.

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