Discussion in 'Geothermal Heat Pump Applications' started by Superchief, Dec 11, 2022.

  1. Superchief

    Superchief Member

    Anyone ever design/combine ASHP air-to-water + GSHP as a 2 stage system where either can be the first stage depending upon outside temperatures?

    Assuming the control issue can be solved is seems this would be an effective way of taking advantage of both systems strengths and you could possibly use a less expensive ASHP without injection assuming you have an adequate buffer.

    I am zone 4a, 12 ton system.
  2. gsmith22

    gsmith22 Active Member Forum Leader

    I'm not aware of anyone doing this and can't forsee the use case that would warrant it either. GSHP is more efficient than ASHP in cooling and far more efficient in heating (especially in zone 4a) so if you went to the trouble/cost to install the GSHP, you should just use that. ASHP's main benefit is the initial installation cost is much less than GSHP becuase you don't have all the ground heat exchanger work. But ASHP are less efficient/more costly (lower COP than GSHP) to run over time relative to GSHP. I'm not knocking the tech, as I have a hybrid ASHP as my hot water heater and can certainly understand why someone in say the southern US would install an ASHP instead of a GSHP where the moderate air temps allow reasonalbe use cases for heating and cooling a home.

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