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Thread: Save that heat!

  1. #1
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    Save that heat!

    I am a hvac apprentice in Oklahoma and so i work in the business of throwing away 10's of thousands of btu's of heat every day most of the year all while burning gas or electricity to make hot water so i have been thinking about ways to reduce that waste.
    I drew a diagram of my idea and would like to post it but i am not seeing how to post pictures.
    Could anyone help me out there? I use an android phone. Do i need tap-talk?

  2. #2
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    Look up heat recovery chillers which will use the condensing loop to supplement boilers. Used frequently in hospitals or hotels where there’s a common demand for heating and cooling.

  3. #3
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    Quote Originally Posted by 3generations View Post
    Look up heat recovery chillers which will use the condensing loop to supplement boilers. Used frequently in hospitals or hotels where there’s a common demand for heating and cooling.
    I know my idea is not a new one but i just had some thoughts on combining existing technology in a residential setting.

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  4. #4
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    They do have some options available to use the heat for residential pools.

  5. #5
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    Haha I finally figured it out.

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  6. #6
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    Here is my idea. Condensor loop goes through hot water heat exchanger probably plumbed next to a stratified hot water tank with a pump sucking the coolest water off the bottom to run to the condenser then the condensed or partially condensed liquid goes through the outdoor condensing unit with a fan control that runs the fan if more subcooling is needed. Then it goes through the condensate water heat exchanger for some massive subcooling. Then i have to figure out how to switch from using the indoor evaporator to using the "condensor coil for heatpump mode which would heat water only and the hot water could be used for home heating or backup heat could be used.

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  7. #7
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    You could look into pool desuperheaters and issues for ideas you’d run into. You would need to account for the additional refrigerant charge and where to store that charge when not in mode. Heat pumps would be particularly hard when switching modes.

    It’s a great topic and still being evaluated by engineers for different uses but tampering with a machine will likely alter effect your warranty as well.

  8. #8
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    Talk about a run-on sentence. :-)

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  9. #9
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    Quote Originally Posted by 3generations View Post
    You could look into pool desuperheaters and issues for ideas you’d run into. You would need to account for the additional refrigerant charge and where to store that charge when not in mode. Heat pumps would be particularly hard when switching modes.

    It’s a great topic and still being evaluated by engineers for different uses but tampering with a machine will likely alter effect your warranty as well.
    Yes definitely would void any warranty.
    I dont eaven have a house in mind i just like discussing ideas and doing "armchair design.

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  10. #10
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    Quote Originally Posted by 3generations View Post
    You could look into pool desuperheaters and issues for ideas you’d run into. You would need to account for the additional refrigerant charge and where to store that charge when not in mode. Heat pumps would be particularly hard when switching modes.

    It’s a great topic and still being evaluated by engineers for different uses but tampering with a machine will likely alter effect your warranty as well.
    Those are key problems: How much extra freon. And how to make it function properly in all modes.

    I think it would not be hard at all to accomplish. If it was actually to go to market though I think it may be a lot harder to make it affordable.

    I think an accumulator could be used to take up the extra charge when switching between evaporator coils but it may have to be fairly large to take up the extra liquid that would have been in the outdoor condensing unit when the outdoor unit runs in evaporator mode.

    But I was contemplating how it could be plumbed so that the indoor coil would be shut with a solenoid and used as an accumulator to store some of the extra refrigerant that would have been in the outdoor coil during normal cooling operation. The purpose of this would be that during cooling operation any heat that could be pumped into the hot water tank would be but when the hot water tank became hot enough that it would not properly condense then the outdoor condenser would take over from there but during heating season the unit would just pump all the heat into the hot water tank and then a hot water coil in the floor or some other heated water system could be used for heating.
    (I am working on my writing skills. That never was my strong point.)


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  11. #11
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    Looks like there is already a very good option on the market.
    Thanks for pointing me in the direction of desuperheaters that brought up lots of interesting info.
    This covers most everything i was thinking in a very neat unit. They went about it in a different way then i had thought but it makes more sense.
    https://www.chiltrix.com/

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  12. #12
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    I am looking for a water cooled condenser for ductless AC

  13. #13
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    Sorry I can't help you there but I like the idea.
    Please post if you find anything.
    My googler failed me this time.
    Quote Originally Posted by Premi View Post
    I am looking for a water cooled condenser for ductless AC
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  14. #14
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    https://unitedcoolair.com/

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  15. #15
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    .

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  16. #16
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    I like the design of electric solar panels going to an Electric HW tank to a heat exchanger or old coil before the air handler with it hooked up to a 12v water pump controlled by a Tstat to a 24v relay with its own battery/ inverter also charged by the solar panels

  17. #17
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    I saw a system to this once in a Hospital Laundry. The AC unit cooled a commercial laundry, a huge load that ran year round. The condenser was water cooled to keep up with the load. The cool thing was the condenser would preheat water to the boiler system that fed steam into the building. Cool way to save those BTU's. It was a custom system that could dump the water down the drain if the boiler preheat tank was full.
    If you are going to heat water in a residential tank you may find that you tank is to small, you may need to still have a air cooled condenser outside and when you hot water tank reaches setpoint it diverts the hot gas to the outdoor coil.

  18. #18
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    Quote Originally Posted by MKnight88 View Post
    I saw a system to this once in a Hospital Laundry. The AC unit cooled a commercial laundry, a huge load that ran year round. The condenser was water cooled to keep up with the load. The cool thing was the condenser would preheat water to the boiler system that fed steam into the building. Cool way to save those BTU's. It was a custom system that could dump the water down the drain if the boiler preheat tank was full.
    If you are going to heat water in a residential tank you may find that you tank is to small, you may need to still have a air cooled condenser outside and when you hot water tank reaches setpoint it diverts the hot gas to the outdoor coil.
    Sounds like an interesting system. I love custom systems they are so interesting.

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  19. #19
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    Many heat recovery systems have water addons that can do just this thing. Doing this with systems that aren't built for it would need the water tank load correctly and then someway to vary the amount of load and refrigerant the system dealt with.

    In regards to watercooled systems, there are a few small makes who do it, then the big boys have some VRF/V's that can cope with all sorts of loads.

  20. #20
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    A number of companies make brazed plate heat exchangers that can be used for heat recovery, condensers or desuperheaters. Any used for domestic water must be vented double wall per code.

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