Ever made a dedicated water heater with a condenser outside?
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  1. #1
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    Ever made a dedicated water heater with a condenser outside?

    I live in TX and have a GE hybrid water heater. It has significantly reduced my electric bills. The problem is, especially during the cooler months that it won't keep up unless it uses the electric heat. Now I have added in a 70 gallon whirpool tub and even in the summer it won't keep up (50 gallon WH). I have been contemplating issuing a spare 2.5 ton condenser I have at the shop to build a much higher recovery rate WH. Anybody tried this? Pitfalls? Struggles?

  2. #2
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    I didn't explain the condenser correctly, I would make it a heat pump.

  3. #3
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    And use a water source coil for hx I'm assuming?

    I have contemplated doing the same myself. I have a waste heat recovery system on the main heat pump but recovery is slow and nonexistent on low load days.

    My main design concern is when water temp approaches 120 how to keep condensing the refrigerant.

  4. #4
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    The GE hybrid WH I currently have does a great job even with electric locked out to keep water at 130. It runs 410a but it just does not recover fast enough.

  5. #5
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    Do you have the 2nd gen ge hybrid? Cause I thought they used 134a. The 1st gen did.

  6. #6
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    Quote Originally Posted by Jbart View Post
    I live in TX and have a GE hybrid water heater. It has significantly reduced my electric bills. The problem is, especially during the cooler months that it won't keep up unless it uses the electric heat. Now I have added in a 70 gallon whirpool tub and even in the summer it won't keep up (50 gallon WH). I have been contemplating issuing a spare 2.5 ton condenser I have at the shop to build a much higher recovery rate WH. Anybody tried this? Pitfalls? Struggles?

    Combining the spare "HP" with a large enough storage tank will get you more draw capacity. With the new tank connected in series with the existing tank the two will potentially raise the GPH rating to a level that will satisfy your needs. Will the added capacity take care of your needs..... only the math will tell for sure.

    Pitfalls...... it's an experiment with potentially little investment if you can come up with all the materials needed at the right price. What's the worst it can do... not work?
    Struggles........ do your homework and research the engineering and specs of the GE hybrid unit and upscale it. You're not reinventing the technology, you're just choosing not to buy it already made.

    I like experimenting just as much as the next guy, but if the only real issue is filling the hot tub in the colder weather I think I'd look for a "spare" instantaneous gas water heater or an electric one.

    If the core issue is the recovery and hot tub demand capabilities of the GE unit, in other words it kicks in the electric resistance heating because you've drawn too much water from the tank to fast...... how about a second tank to increase it's storage and draw capacity with a HW recirc pump between the two? Again the math would have to be done to see if this would work.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  7. #7
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    Quote Originally Posted by firecontrol View Post
    Combining the spare "HP" with a large enough storage tank will get you more draw capacity. With the new tank connected in series with the existing tank the two will potentially raise the GPH rating to a level that will satisfy your needs. Will the added capacity take care of your needs..... only the math will tell for sure.

    Pitfalls...... it's an experiment with potentially little investment if you can come up with all the materials needed at the right price. What's the worst it can do... not work?
    Struggles........ do your homework and research the engineering and specs of the GE hybrid unit and upscale it. You're not reinventing the technology, you're just choosing not to buy it already made.

    I like experimenting just as much as the next guy, but if the only real issue is filling the hot tub in the colder weather I think I'd look for a "spare" instantaneous gas water heater or an electric one.

    If the core issue is the recovery and hot tub demand capabilities of the GE unit, in other words it kicks in the electric resistance heating because you've drawn too much water from the tank to fast...... how about a second tank to increase it's storage and draw capacity with a HW recirc pump between the two? Again the math would have to be done to see if this would work.
    Yes I have thought through all of this in depth and researched it. I guess I like the idea of the remote heatpump so it will not blow cold air in my garage. It's nice in the summer but not in the winter.

  8. #8
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    Quote Originally Posted by SBKold View Post
    Do you have the 2nd gen ge hybrid? Cause I thought they used 134a. The 1st gen did.
    You are right and I am wrong. I was sure I read that it used R410a. Hmmm back to the drawing board.

  9. #9
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    Do you think the condenser coil inside the water heater wil be large enough not to trip high pressure in the OD unit during normal operation?
    Keep in mind, if you make some homemade heat pump water heater, you are putting your family at risk, and violating code, without having an atmospheric vent between the refrigerant and potable water source.
    "The only true wisdom is in knowing you know nothing" Socrates

  10. #10
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    Quote Originally Posted by mgenius33 View Post
    Do you think the condenser coil inside the water heater wil be large enough not to trip high pressure in the OD unit during normal operation?
    Keep in mind, if you make some homemade heat pump water heater, you are putting your family at risk, and violating code, without having an atmospheric vent between the refrigerant and potable water source.
    I am very aware of code. I have two master electrician licenses and a mechanical contracting license. I am not talking about some Jerry rigged thing. The one I currently have is not violating any codes so I am not sure what you are referring to on endangering my family.

  11. #11
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    I made up my heat pump water heater with a used coleman 2.5 ton outdoor unit,it's now in the 20-23yr age range.A 3 ton coaxial tube heat exchanger and a bronze circ pump.This preheats the water in 2- 50 gal elec tanks to around 120deg, that then go to a 3rd elec tank to boostl up to 140f if needed.
    I put a penn hi pressure cut out on the od fan for the summer hi temp's. Its been working good since install 11 yr's ago.Have not needed to turn on the power for the 3rd tank yet. For all the free or almost free parts i used it's been great. Now that this has been said i,ll have water heaters leaking and or the od coil will start leaking.

  12. #12
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    No offense Master J, I was simply referring to the need for the tubing to be coax. If you use single wall condenser tubing inside a water heater, there is potential for contamination.
    I've watched quite a few fellows on YouTube with the "make your own heat pump water heater."
    I wasn't sure if you were just updating your GE or making a whole new unit.

    If you're just upgrading the compressor and evaporator, I would just be concerned about capacity matching. I wonder what kind of metering device those things use?
    A two stage might be ideal. Low for Summer, High for Winter.
    "The only true wisdom is in knowing you know nothing" Socrates

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