Page 1 of 2 12 LastLast
Results 1 to 13 of 15
  1. #1
    Join Date
    Oct 2006
    Location
    Emerald Coast, FL 30.1N 85.8W
    Posts
    681

    Hmm what efficiency?

    From a post in R&I on this site, I think it's likely that these so called higher SEER R-410a residential units actually cost more to run than lower SEER R-22 units due to the higher pressures.

    Since you need more amperage to run a compressor at higher pressures in a R-410a unit, your electrical cost will unequivocally be higher.

    Debates please.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,790
    If a 12 seer r22 was more efficent then a 13 seer r410a.
    Then the r410a wouldn't be 13 SEER.

    Your confusing higher pressure reading, with compression ration.

    The pressures are higher on both the vapor and liquid line, but the compression ratio is lower, so it takes less amps to run the compressor.


    Contractor locator map

    How-to-apply-for-Professional

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

  3. #3
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    HHHmmm.. I always thought it was watts and power factor that determined final cost of operation

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,790
    Originally posted by hvaclover
    HHHmmm.. I always thought it was watts and power factor that determined final cost of operation

    Sort of like 12 seer, 12 btu's to the watt.
    And 13 seer, 13 btu's to the watt.
    Contractor locator map

    How-to-apply-for-Professional

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

  5. #5
    Join Date
    Oct 2006
    Location
    Emerald Coast, FL 30.1N 85.8W
    Posts
    681

    that's the argument I got from a well respected HVACR teacher

    Thanks for your input.

    He basically said that your just operating at a higher pressure level -- but higher pressure level means more Force to maintain at a constant working level.

    In addition, my 95 Dodge Diesel truck runs at a much higher compression ratio than the newer Dodge Diesel trucks, but I get more mpg (same displacement & horsepower). Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?



    Originally posted by beenthere
    If a 12 seer r22 was more efficent then a 13 seer r410a.
    Then the r410a wouldn't be 13 SEER.

    Your confusing higher pressure reading, with compression ration.

    The pressures are higher on both the vapor and liquid line, but the compression ratio is lower, so it takes less amps to run the compressor.


    [Edited by emcoasthvacr on 12-05-2006 at 07:38 PM]

  6. #6
    Join Date
    Apr 2002
    Location
    Omaha, NE
    Posts
    1,561
    > Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?

    One reason is that a gallon of diesel fuel contains 139,000 BTUs, and a gallon of gasoline only 124,000 BTUs.

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    It takes the same amount of energy to compress 1 pound of vapor from 1 psia to 10 psia as it does to compress 1 pound of the same vapor from 10 psia to 100 psia.

    Its all about the compression ratio relative to the absolute pressures.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Oct 2006
    Location
    Emerald Coast, FL 30.1N 85.8W
    Posts
    681
    snewman,

    I'm comparing the higher compression diesel to the lower compression diesel -- same engine, but much lower compression ratio due to the newer government mandated diesel emissions.

    My engine has 20% higher mpg at the same cost. This doesn't include the 40% higher engine cost that I can't recover over the life of the engine or truck -- I think the same thing applies to AC units when you compare the costs.

    Originally posted by snewman24
    > Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?

    One reason is that a gallon of diesel fuel contains 139,000 BTUs, and a gallon of gasoline only 124,000 BTUs.
    [Edited by emcoasthvacr on 12-05-2006 at 09:48 PM]

  9. #9
    Join Date
    Oct 2006
    Location
    Emerald Coast, FL 30.1N 85.8W
    Posts
    681

    relative to atmoshperic pressure?

    only in an adiabatic process, which never occurs in reality.

    Originally posted by mark beiser
    It takes the same amount of energy to compress 1 pound of vapor from 1 psia to 10 psia as it does to compress 1 pound of the same vapor from 10 psia to 100 psia.

    Its all about the compression ratio relative to the absolute pressures.

  10. #10
    Join Date
    Jul 2006
    Location
    Washington
    Posts
    285
    They only prove their effiency in ideal (laboratory) controlled conditions. Don't fall in line with the SHEEPLE.

    The thing thats gets me

    More effiency but more controls to go down in the life of a unit. Sure save hundreds on paper effiency but spend more on actual maint. cost.


  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,790

    Re: that's the argument I got from a well respected HVACR teacher

    Originally posted by emcoasthvacr
    Thanks for your input.

    He basically said that your just operating at a higher pressure level -- but higher pressure level means more Force to maintain at a constant working level.

    I



    Originally posted by beenthere



    [Edited by emcoasthvacr on 12-05-2006 at 07:38 PM]
    The pressure you and I read on the guages, is referenced to Atmosheric pressure.
    But neither an r22, or r410a compressor is sensing atmosheric pressure, they only move gas in an enclosed eviroment attempting to move x amount of refrigerant.
    Contractor locator map

    How-to-apply-for-Professional

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

  12. #12
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Originally posted by travistee
    They only prove their effiency in ideal (laboratory) controlled conditions. Don't fall in line with the SHEEPLE.

    The thing thats gets me

    More effiency but more controls to go down in the life of a unit. Sure save hundreds on paper effiency but spend more on actual maint. cost.

    Don't crab, that's job security.

  13. #13
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    No, relative to absolute pressure. You figure compression ratios with absolute pressures.
    Remember, its not just the head pressure that is higher, the suction pressure is higher too, it is the ratio between the pressures that determins how much work the compressor has to do. The compression ratio between the low and high side of a R410a system is lower than with R22, so the compressor is actually doing less work, even though the pressures are higher.
    If more government is the answer, then it's a really stupid question.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event