Climate Master Desuperheater

Discussion in 'Geothermal Heat Pump Applications' started by Bostonceltics, Feb 14, 2017.

  1. Bostonceltics

    Bostonceltics New Member

    I am running a climate master tranquility 22 , 3 ton with open loop. The entering water temp is 47 degrees. I would like to hook up the desuperheater. I plan to buy 2 used electric water heaters to save install cost. Is there an efficiency rating I should look for? Any brand or feature recommendations? I guess the hot water generation for my heat pump is part time, according to a document on the internet. That being said, will my heat pump generate hot water during heating season?

    Thank you
     
  2. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    no, no, yes and yes.
     
  3. Bostonceltics

    Bostonceltics New Member

    Thank you. Do both tanks need to be similar in size and capacity? I am seeing some used heaters short and wide and others tall and thin with different gallon capacitites.
     
  4. Bostonceltics

    Bostonceltics New Member

    Would an electric on demand heater be the more efficient way to go to boost the water temp going into the house?

    Thank you
     
  5. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    A 50 gallon preheat / buffer tank should do nicely and should be available inexpensively. Finishing tank size is more dependent on number of bedrooms. Plumbing code sets minimum first hour delivery rating of tank water heaters based on number of bedrooms and bathrooms.
     
  6. Bostonceltics

    Bostonceltics New Member

    Would a heat pump hot water heater be a good choice for a finishing tank? Or is a strict electric tank the best way to go?

    Would it make sense to use my desuperheater for radiant floor heat where its part time?

    Thank you!
     
  7. mtrentw

    mtrentw Member Industry Professional Forum Leader

    I use a heat pump water heater for my finishing tank. It makes a lot of sense for me in Maryland. They make more sense in cooling dominated climates because they do steal heat from the room surrounding. If that space is heated by geothermal, the efficiency is better than straight electric resistance heat.
     
  8. ChrisJ

    ChrisJ Active Member Forum Leader

    I don't think a desuperheater should be used for radiant floor.
     
  9. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I agree with Chris - recommend not using desuper for radiant floor.

    Using an HPWH as a finishing tank depends on the economics of the situation. The $ may or may not pencil out. The incremental cost of an HPWH over a conventional storage electric resistance tank remains quite high, and it would take some diligence to assure that incremental cost would be recovered during the economic life of the water heater.
     
  10. Bostonceltics

    Bostonceltics New Member

    Thank you everyone. Where I live there is good hpwh rebates, so that appears to make them alot cheaper than strict electric. Im a little concerned about loosing heat in my basement but I am thinking I would get the geo spring with the duct kit and discharge the cold air into my barn. My basement could use some dehumidification anyways. Its not a finished basement.
     
  11. ChrisJ

    ChrisJ Active Member Forum Leader

    I run the GeoSpring without a desuperheater hooked up. I am in RI.

    It's in a mechanical room 9' X 15', I typically leave the door open to the basement. I see about a 2-3 degree difference in temp with the semi conditioned 30 X 40 basement.

    I would say that with an up-powered electric tank before the HPHW and some fairly long run times of your heat pump, your HPHW will run less then mine ( of course depending on hot water usage ect ect..)

    I got a $750 rebate from elec company on the $1000 water heater. Paid $200 to have a plumber install it. Had to be installed by pro for rebate.

    Good luck
     
  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    There is a bit of a misconception running around that it is better to send an HPWH's discharge outdoors in heating-dominated climates. Nothing could be further from the truth anytime outdoor temp is less than 45-50*F

    Why is that?

    Any air discharged outdoors by an HPWH has to be replaced...from outdoors!

    Suppose an HPWH in a 60-65*F basement blows its 45-50*F discharge air outside....That airflow is replaced by air from outdoors, which up north during most of the heating season is substantially cooler than 45-50*. That replacement outdoor air has to be heated to at least basement temperature (more likely to house indoor temperature since most infiltration likely occurs above grade into heated rooms).

    An alternative to avoid that is to duct both sides of an HPWH. That seems to make sense unless one considers that the HPWH offers both free cooling and dehumidification, both of which are lost in a fully ducted situation.

    Modeling the energy impact of an HPWH in heating-dominated climates is tricky. My "shooting from the hip" educated guess is that an HPWH in semi-conditioned space (such as a basement) is best left unducted to the outdoors owing to the issues I wrote above coupled with an HPWH's generally desirable dehumidification.
     
  13. Bostonceltics

    Bostonceltics New Member

    If I could not duct the heat pump outside, that saves me $100 on the duct kit. Im a little leary of my basement temps staying warm enough for the hpwh to work right in winter. Its nice I can just go full electric with the hybrid tank if needed, I believe.
     
  14. ChrisJ

    ChrisJ Active Member Forum Leader

    "Its nice I can just go full electric with the hybrid tank if needed, I believe."

    Yes you can, the GeoSpring has 4 modes: Full electric (no heat pump), High Demand, Hybrid, Heat Pump Only.
     
  15. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Avoid Geospring for new projects - GE is stopping production.
     
  16. arkie6

    arkie6 Member Forum Leader

    Curt, do you have any recommendations for a heat pump water heater?
     
  17. ChrisJ

    ChrisJ Active Member Forum Leader

  18. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Ark - Well, I just ordered an 80 Gallon Rheem HPWH from the big orange box. It is the latest model with an EF of 3.5. You'd think, having attained 50, I'd have learned by now not to buy "the latest model", but I'm still occasionally wowed by bright shiny objects.

    I hedged my bet by plunking down another $70 for 5 more years warranty.

    Chris - Thanks for posting that; I hadn't known. It is good that technology will remain available

    The A.O Smith / State models have been reliable performers at steadily increasing Energy Factors and decreasing noise.
     
  19. Bostonceltics

    Bostonceltics New Member

    I was thinking now to just use a preheated buffer tank from the geothermal and then feed that water to my existing boiler mate. Seems even doing that would help save on oil use.

    Anyone heard of someone doing that?
     
  20. ChrisJ

    ChrisJ Active Member Forum Leader

    Sure you could do that but it still leaves your boiler running all summer.
     

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