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  1. #1
    Join Date
    Jul 2008
    Posts
    28

    Carrier Heat Pumps - Colder Climates

    I ran into someone at a home show in Philadelphia, PA and to may shock he was showing off a new heat pump unit from Carrier. I pulled him aside and asked why he was trying to push heat pump technology in an area like Pennsylvania. Anyone I have ever known with a heat pump in this area has a cold house in the winter.

    So the guy (who clearly is a Carrier dealer) goes on to say that Carrier has a brand new heat pump unit that is "game changer". Here are the numbers he gave me, which... I cannot validate online or on Carriers website.

    For the 36,000 BTU unit, he claims the unit gets all 3-ton when outside ambient is 45 F or above. Now brace yourself.... The units efficiency drops to 32,000 BTU output at 17 F ambient outside temp. Normally, for a heat pump, 17 F outside temp, I expect a 3-ton unit to fall to like 12,000-15,000 BTUs for a 3-ton unit.

    If these numbers are correct, then yeah, thats great. And at 1KW per ton, this heat pump would work great in this area, but I just cant believe those numbers, it almost goes against basic thermodynamics.

    Any ideas what this guy was talking about?

  2. #2
    Join Date
    Nov 2011
    Location
    Sturbridge, MA
    Posts
    103
    While i guess you gotta believe his numbers we have a few units here that are fairly new and they arent even close to that. They start losing it at about 35f.
    Id like to see some other info on that model. I know the sanyo eco-i still works at way below zero so the technology is certainly emerging.

  3. #3
    Join Date
    Apr 2011
    Location
    SE Washington
    Posts
    535
    25VNA greenspeed and yes, his numbers are correct, its a vfd controlled unit, carrier suggest oversizing by 1 ton, info is available on ARI website, look up 25vna036 matched with an fe4anf05, impressive for sure and an hspf of 12.5
    Total Energy Management, inc

  4. #4
    Join Date
    Apr 2011
    Location
    SE Washington
    Posts
    535

    25vna

    Total Energy Management, inc

  5. #5
    Greenspeed and Nordyne's IQ drive systems use inverters to modulate the speed of the compressors - very impressive technology.

    Inverter heat pumps have been pervasive for years outside the U.S. (even in third world countries). I don't know why it has taken so long for it to get a foothold in the U.S. Cost alone can't be the issue (yes, I know the U.S. models cost a small fortune) - but, again, elsewhere on the planet the inverter premium is only a few hundred dollars on a 2 ton system, perhaps five hundred on a 3 ton.

    If you can swing it, I'd definitely go with an inverter system - Carrier or Nordyne, I'd guess they are likely comparable.

    In most situations, heating demand is much larger than A/C demand - making it impossible to perfectly size a heat pump. Either it is way oversized for cooling, and right sized for heating, or it is right-sized for cooling, and undersized for heat.

    With inverter heat pumps, it is possible to right size both heating and cooling - you can oversize the A/C so that there will be enough heating BTU's. In A/C mode, the system will just run at a lower speed. Added benefit - the inverter systems are even more efficient at partial load - another argument for oversizing an inverter system.

    There is an excellent study done by some government agency on one of these systems (Nordyne's - but, like I said, Carrier's greenspeed is pretty much the same thing) - I'll track down the link if anyone is interested. The gist of the study's results - in real world usage, the inverter systems are even more efficient than their SEER/HSPF ratings suggest.

  6. #6
    Join Date
    Jan 2012
    Location
    indy
    Posts
    471
    wouldnt this be a very high cost to install in compared to its savings? Not to mention when something goes wrong there goes the savings over ten yrs

  7. #7
    Join Date
    Dec 2010
    Location
    Toronto
    Posts
    1,253
    I think it depends on what you want to do with it. Inverters are a good idea when you are heating air directly like a ductless split but if you heat a tank of water for floors, there is almost no point as the change in water temp is too slow to make a difference. In this case, more important would be an EEV over a TXV. A big part of the Mits increased performance is due to the the EEV.

  8. #8
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,903
    Normally, for a heat pump, 17 F outside temp, I expect a 3-ton unit to fall to like 12,000-15,000 BTUs for a 3-ton unit.
    Modern 13+ seer heatpumps do much better than that.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  9. #9
    Join Date
    Dec 2010
    Location
    Toronto
    Posts
    1,253
    Time will tell but the chinese units have pretty short lifespans from what i hear in Europe so I guess you get what you pay for.

  10. #10
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,903
    Carrier isn't chinese - yet.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  11. #11
    Join Date
    Dec 2010
    Location
    Toronto
    Posts
    1,253
    No but most of the stuff in Europe with known names has a lot of Chinese parts in it. Those GE heat pump water heaters that are now out are completely Chinese IIRC.

  12. #12
    Join Date
    Apr 2010
    Location
    Red Deer, Alberta
    Posts
    653
    These things (geothermal) don't work in cold climates where the ground/groundwater temperature is extremely cool and the outside air temperature is also very cold. Go figure...!

    I defy anyone to show me one in my area that works cheaper than the normal natural gas systems common here...

    If you can prove it (with a year's worth of heating bills), I'll buy you a drink at your favourite coffee shop...

    Another worth...

  13. #13
    Join Date
    Dec 2010
    Location
    Toronto
    Posts
    1,253
    I'm not sure anyone can get cheaper NG prices than you should have in alberta. Right now we are at $0.11/m3 (+ delivery of another $0.11). What are your electrical rates?

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