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Replacing old geothermal with Mitsubishi or Fijitsu?

bselltiz | Posted in General Questions on

I own an 8k sq foot medical building in Long Island. It has an aging open loop Geo Thermal system that honestly I am not a big fan of. I would like to replace it with newer tech from one of the above manufacturers if possible. The reasons are many, the equipment is end of life, upkeep costs, poor reliability etc. I am not tied to those two manufacturers but they are the ones I know about.

Inside each suite are small exam rooms so I will have to use the existing ducting. 4 of the units are located above the ceilings, 2 are on the floor.

I’m not sure if I am even heading in the right direction. I really want to avoid the constant headache of this existing system but what do I use in it’s place?

Thank you, Brian.

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  1. Expert Member
    Akos | | #1

    Your geo is feeding the air handlers with water, so the simpler replacement might be an air to water heat pump.

    You would need somebody to check the sizing of the existing system and air handlers and see if one of the units can work. The air source heat pumps generally provide lower temperature water than a geo unit, but if your air handlers have a bit of extra capacity it can probably be made to work.

    Most units that big are designed for commercial application, you would have to find an installer that is familiar with them.

    You can try to see if something like a Unico chiller, LG Multi VS with a hydro kit or a Daikin Altherma can work.

  2. joshdurston | | #2

    Do you have various ceiling hung heat pumps, or a central plant distributing conditioned water to coils?

    If you have ceiling hung heat pumps I would recommend getting some load calcs done to confirm the sizing first.

    I would include LG on your short list along with Mitsubishi and Fujitsu. My Southern Ontario Canada office is conditioned by a LG MultiV commercial VRF system. It works quite well, except for a couple of boneheaded groupings and space sensor placements. The operating costs compared the RTU's on our old building are drastically lower.

    I would recommend going for a system that has heat recovery capability (simultaneous heat cool). This allows you to move waste heat from a cooling dominated meeting or server room, into a heating dominated space like an entrance vestibule. In commercial buildings in cold climates I think this makes a lot of sense.

  3. bselltiz | | #3

    I have 6 heat pumps being fed from the well which then goes into a holding tank and then back into the ground I think. There is a cooling tower in the mix for the summer and a small boiler for winter as well. I'm not really sure how it all works, never learned alot about Geothermal. I do know that my units do not have any extra capacity, they fight to keep the temp up during colder spells.

    Thank you both for the LG recommendations, I will definitely check them out as well. I also do like the idea of capturing heat and although I don't think it is appropriate here I always wanted to do that in my home.

  4. Expert Member
    NICK KEENAN | | #4

    I realize you probably just want to get your system fixed, but I think you're going to end up ahead if you figure out why your current system isn't working before buying a new one. A manual J to see if it was sized properly would go a long way.

    The wells are the expensive part of a ground-source system. If the wells were never sized properly, or are clogged or are otherwise not functioning, yeah, ditch them and go with air-source. But if the wells are in good shape and sufficiently sized, and it's the above-ground components that are the problem, I'd at least price a replacement ground-source system.

    1. joshdurston | | #6

      Agree, there is also the potential to use your loop with modern inverter units rather than air. Many of the commercial options come in air or water source configurations.

  5. user-6976637 | | #5

    Mitsubishi's are now made in China, had I found that fact out I would have looked
    elsewhere as i despise that thought.

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