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Community and Q&A

Help with an air-to-water heat pump system

Hominik | Posted in General Questions on

Been reading the blogs and Q&A sections here for quite a while and finally feel I am ready to ask questions and help.
I am designing a heating/cooling/hotwater system using air-to-water heat pumps for my home.
I believe I have a decent logical & workable design.
HeatPump to FanCoil Air Handler (for cooling, humidifying etc)
Heatpump to Hotwater tank
Heatpump to buffer tank for Infloor Radiant
I would love to have a pro consult on some of the finer aspects of the design, like Expansion tank placement/sizing, air-scoop, air-vent, circulator pump type (Fixed/Variable/Delta-T etc)
Would be even better if I can get help in the actual installation of the system.
I am in the south-west corner Ohio, near Dayton

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  1. GBA Editor
    Martin Holladay | | #1

    Q. "I would love to have a pro consult on some of the finer aspects of the design."

    A. I agree -- you need to hire a consultant. Start by looking for a mechanical engineer.

    One problem you may encounter is that there haven't been many residential air-to-water heat pump systems installed in the U.S., so it's hard to find a mechanical engineer with experience designing and installing these systems.

    I hate to throw cold water on your plans, but the fact that this type of system is exceedingly rare, and the fact that experienced system designers and installers are extraordinarily hard to find, is an excellent argument in favor of installing ductless minisplits.

  2. Hominik | | #2

    Hello Martin,
    I completely understand your advise regarding the difficulty in finding experienced designers and installers.
    To me, the fact that this type of system is exceedingly rare is not a deterrent, but a challenge and a motivator :)
    To give an example, over 10 years ago, I designed and built my first and only home, using concrete walls (ICF), concrete floors (with embedded pex pipes for heating) poured on steel decking, resting on steel joists and girders. It was challenging, but I persevered and did it! I did hire a P.E. to go over my plans to ensure I wasn't messing up big time.

    This HVAC system would help me take the house to it's final desired state.

    For this system, I feel someone with experience in hydronic heating would be able to help with the pieces I need help with, and yes, I am having trouble finding those pros too!
    Touché :)

  3. Expert Member
    Dana Dorsett | | #3

    The LG Multi V and Multi-V S fully VRF systems using one or more of their Hydro Kits might be cheaper and better than inventing your own Rube Goldberg contraption with componentents from divers vendors. The Multi-V S (single phase power) versions range in size from 2-5 tons, and can simultaneously heat some zones while cooling others. The bigger ones are targeted at commercial building applications and take 3 phase power, which you may not have on hand.

    The BKDX80 and BKDX50 air to water heat pumps in the schematic may or may not be able to cut it at your winter extremes (do you have access to capacity performance across temperature, or any other technical data on them?) , but they seem pretty big to work efficiently with loads a normal sized US house:

  4. Expert Member
    Akos | | #4

    You might have better luck talking to somebody that does geothermal design. Whether its ground source or air source the interior bits are pretty close.

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