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  1. #1
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579

    A heat pump is operating in the heating mode. The lower the outside air temperature, the

    a. more efficient the heat pump.
    b. higher the SEER rating.
    c. higher the compression ratio.
    d. lower the balance point.

  2. #2
    Join Date
    Feb 2005
    Location
    Central Alabama
    Posts
    466
    my guess is C

  3. #3
    Join Date
    Oct 2003
    Location
    Florida's space coast
    Posts
    2,538
    I'll go with C also.
    We've been doing so much,for so long,with so little, that now we can do almost anything, with nothing at all.

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,296
    Thinking out loud here...if I remember correctly, the closer together the suction and discharge pressures are on a compressor, the lower number there will be on the compression ratio.

    So, with a heat pump in heat mode, say it's running a suction pressure around 50 psia, and head is up around 270 psia, that's 5.4:1 compression ratio, whereas if same heat pump was in cooling mode on a hot day running same head pressure psia but suction around 84 psia, that's 3.2:1 comp ratio.

    I will also pick "C" as being correct.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #5
    Join Date
    Feb 2005
    Location
    Dothan, Al
    Posts
    3,453
    I'll agree with everyone else - C

  6. #6
    Join Date
    Mar 2004
    Location
    Gone
    Posts
    5,340
    You can eliminate the first two from facts as we already know which is the farther north you go with a heat pump, which is a colder climate and would give you the same scenario being described, the less efficient it is.

    The 3 rd answer is the right answer as already described. The farther apart the pressures are, the higher the compression ratio.

    So “C”, all you have to do is eliminate the bad guys.


    [Edited by madeinusa on 08-06-2005 at 08:22 PM]

  7. #7
    Join Date
    Feb 2005
    Location
    Richmond
    Posts
    480
    Well Im no HVAC Pro so I will just guess...

    I dont think it could be A because a H/P removes heat from the air outside and puts it inside...

    I dont think it could be B because it would seem the lower the temp outside, the less efficent the system would be.

    Not entierly sure what a balence point is but if it's the temperature of when not to run the electric strips it should not change.

    So the only one left is C. And I have no idea what the compression ratio is (Im just a guy who is really interested in HVAC)


  8. #8
    Join Date
    Aug 2004
    Location
    Tyler TX
    Posts
    676
    I vote for C

    Heat pumps in heat mode don't have a SEER rating, It's an HSPF or COP rating.
    HVAC Contractor, Tyler Texas.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,763
    C.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  10. #10
    Join Date
    Nov 2004
    Posts
    2,927
    D.
    heat pump capacity will decrease and heat loss will increase.

    (lower balance point)

  11. #11
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    D lower the balance point

  12. #12
    Join Date
    May 2005
    Posts
    428
    DDDDDDDDD

  13. #13
    Join Date
    Nov 2004
    Posts
    2,927
    Originally posted by shophound
    Thinking out loud here...if I remember correctly, the closer together the suction and discharge pressures are on a compressor, the lower number there will be on the compression ratio.

    So, with a heat pump in heat mode, say it's running a suction pressure around 50 psia, and head is up around 270 psia, that's 5.4:1 compression ratio, whereas if same heat pump was in cooling mode on a hot day running same head pressure psia but suction around 84 psia, that's 3.2:1 comp ratio.

    I will also pick "C" as being correct.
    I think you might have the correct answer,S'hound,but "your thinking out loud" shows you drifted off to the cooling mode...read the question again please.

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