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Heat Pump to replace my 300k BTU Boiler.

I have searched for decades for an interchangable heat pump for my 300k BTU hot water Boiler. A system where I could use my closed system/radiators for both heating and cooling. Anyone developing one? This is the Holy Grail for many old house owners.

Comments

  • WMno57
    WMno57 Member Posts: 663

  • WMno57
    WMno57 Member Posts: 663
    I borrowed the photo from @Hotrod post in this thread: https://forum.heatinghelp.com/discussion/189670/air-to-water-hp
  • Jamie Hall
    Jamie Hall Member Posts: 20,443
    First off, cooling with a radiator is impractical -- if you run the radiator on cold water it's going to condense and drip all over the floor, unless you are in a dry climate somewhere.

    Second, 300,000 BTUh is a lot of power. Even at a CoP of 3 (which you may not get on a cold day) that'50 KW or so. Over 200 amps at 240 VAC single phase. Got that much power?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    GravityHeat
  • KC_Jones
    KC_Jones Member Posts: 5,354
    Are you sure you actually need 300k BTU? I would speculate on a house at minimum 7500 square feet, most likely a fair amount bigger to actually "need" 300k BTU's

    Have you actually calculated the heat loss of the structure?
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • pecmsg
    pecmsg Member Posts: 3,548

    I have searched for decades for an interchangable heat pump for my 300k BTU hot water Boiler. A system where I could use my closed system/radiators for both heating and cooling. Anyone developing one? This is the Holy Grail for many old house owners.

    You're not going to find a heat pump that can make 180°F water!
    Next is you're going to have to increase the number of emitters by probably 50% to be usable with the lower water temperatures.

    Hot water / Chilled water piping required serious piping insulation and vapor barriers, or you'll have serious flooding during the summer.
  • pecmsg
    pecmsg Member Posts: 3,548
    Keep the existing HW system as a backup and get a Ducted heat pump installed. 2 stories 2 systems!
    GGross
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,006
    edited October 2022
    The answer isn’t one heat pump, but several of you actually need the full 300kbbtu. Or try to 80/20 it and install 150ish of heat pump and keep the boiler for the rest. If you go the ground source route, they make them bigger than 300,000 btu. 

     You’ll have to come up with something else for cooling, like an air handler. 
  • WMno57
    WMno57 Member Posts: 663

    I could use my closed system/radiators for both heating and cooling

    No soup for me, because I did not read past your first sentence. I agree with Jamie. Can't use 100 year old cast iron radiators for cooling. @GravityHeat how do you cool your house now?
    TCO of the monster A2WHP i posted will be much higher than a boiler. MTBF will be a much shorter than a boiler. But you can save the planet!!!
  • hot_rod
    hot_rod Member Posts: 18,208
    edited October 2022
    More questions than answers

    You must do a load cals first
    Then a count and sizing of radiators
    Determine output at 120- 125F
    See if the radiators you have at 120F swt could cover the heat load. I doubt it.

    Even if you could cool with chiller radiators you may need to deal with sweating pipes, condensation dripping from the radiators. All the piping would need to be insulated and sealed.

    A dewpoint control could avoid that, but a cooling load calc would be needed also.

    Cover the AC with some sort of air moving device, mini split or high velocity AH.

    Here is a radiator derate example.

    Certainly you can find commercial HP to cover a load that size. The Mitsubishi folks I met with last week can get 190F from some units the are working on.

    What's in your wallet?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream