Page 1 of 4 1234 LastLast
Results 1 to 13 of 43
  1. #1
    Join Date
    Apr 2005
    Posts
    28
    How do I spec my new ac requirements to get a system that will have high latent heat removal?
    Do oversized or undersized evaporators have a higher latent heat capability
    gn

  2. #2
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Go with a variable speed indoor fan,TXV, and great controls,like Carriers Infinity,or next best Tranes Comfort-R,Or whatever brand you choose has,plus a two speed compressor,and you'll be amazed .

    Most all our Infinity customers,run the system 2 or 3 degrees warmer,with the lower indoor humidity during cooling.

  3. #3
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,022
    That is a good question.
    You need a real cold evaporator coil and a lot of run-time.

    Therefore, do not oversize equipment!

    I will let the other professionals argue over all the different options you could evaluate.

    http://www.udarrell.com/air-conditio...tent-heat.html

    From an initial cost standpoint I personally would stay with the lower 13-SEER rated units, but you will get a lot of arguments to the contrary. It depends on what the buyer can afford upfront.

    As the percent of humidity goes up the latent capacity of the coil goes up! Check the condenser graph on the linked page.
    - Darrell



  4. #4
    Join Date
    Apr 2005
    Posts
    28
    Cant anybody explain in simple language!
    How do you get a "cold' evaporator? Undersize relative to compressor? Or do you oversize to increase the fin area to collect more condensation? I current have a 3.5t; some manufactures tech data don't even have 3.5T evaps; some say use a 3T others recommend 4T.

    Now I do understand Dash answer; throw cubic $ my way!

  5. #5
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    First use a matched system approved by the manufacturer,if you need 3.5 ton,use the 3.5 coil match.In general the larger coil,say a 4 ton matched to 3.5 outdoor,will not dehumidify as well as the 3.5 ton matched coil.

    A TVX(expansion valve)is the prefered metering device ,better humidity control ,in milder weather.


    now go back to my first post,lok at at the comfort a top of the line system can provide,then the cost difference,divide by 15 year life,then365 days a year.Then decicde how much real comfort,in your ,is worth per day.Likely less then a beer!!LOL!!

    Good luck!


  6. #6
    Join Date
    Apr 2002
    Posts
    11,808
    Air handlers by heat pipe technology dehumidify quite well.

    A fresh air intake to the return air and the Air handler fan operating in "Auto" mode will pressurize your home with dry air and reduce humid air from infiltrating in and raising your indoor RH
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  7. #7
    Join Date
    Apr 2005
    Posts
    28
    Dash;
    I do appreciate your time. But most of the answers I see are superfical.
    Example; I have spent much time downloading detail tech date; two examples of what I found;
    One manufacture has a 3.5t condenser units, but only lists 3t or 4t "matching" evaporators. Does the installer guess?
    Rheem tech date has 4 3.5t evaps, but no details on what the tech differences are.
    I called the local Rheem distr. he said and I quote, "we always order just one number"
    Now I expect the Reheem units are probably tall, short, std and high effeciency. I would like to know how do I get the one with the most latent capacity. I asked the man about latent btu's and he acted like I was speaking greek. I don't think the correct answer is get a good contractor, pay top dollar and you will by difinition be happy because you paid the most.
    I would just like to get some "sound tech/engr info" I have talked to 4 installers and they don't even agree if you need TVX or a drier installed. The installer recommended by a distributor said he did'nt like TVX's; go figure. And you wonder why the public throws AC guys and lawyers into the same pool. Sorry for the rant, but after hours of diligent work coming up with nothing from the pro's. It's insulting to be told that a Kia is as good as a Lexus if you have a good mechanic!!

    gn

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,556
    In your example of the 3.5 ton condenser, and both a 3 and 4 ton evap being a match, the 3 ton would have the higher latent capacity with a txv, as a rule, (not engraved in stone).

    Contractor locator map

    How-to-apply-for-Professional

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

  9. #9
    Join Date
    Mar 2005
    Posts
    997
    Kia has a ten yr warrenty

  10. #10
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,022
    Originally posted by gencon
    Cant anybody explain in simple language!
    How do you get a "cold' evaporator? Undersize relative to compressor? Or do you oversize to increase the fin area to collect more condensation? I current have a 3.5t; some manufactures tech data don't even have 3.5T evaps; some say use a 3T others recommend 4T.

    Now I do understand Dash answer; throw cubic $ my way!
    Those are good questions, and the mfg'ers and dealers should have the data available on all the equipment matches for contractors to evaluate.

    A more relevant question to the buyer could be - what is the best long-term cost-effective system that will achieve the comfort zone levels demanded.

    The answer to that question is dependent on the proper matching of every element of the entire A/C system.

    My lowest cost pick is, a slightly undersized system at the absolute peek load levels, that has a larger compressor to evaporator coil area, but with extra coil fin area, and a dehumidistat wired in parallel to get the humidity to the desired level. "Always use a TXV refrigerant control."

    The humidistat when it is closed should energize and "open" the closed relay contacts' line to the hi-speed 400-cfm per ton of cooling fan tap and close the N/O contacts to the 325 or 350-cfm per ton blower speed tap. (A double pole double throw fan speed relay; this is "a second fan relay with line power to the N/O side"- comprehend.)

    Do an air infiltration test and reduce it to a minimum.

    http://www.udarrell.com/latent_heat_condensation.html

    [Edited by udarrell on 09-08-2005 at 11:35 PM]

  11. #11
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Originally posted by gencon
    Dash;
    I do appreciate your time. But most of the answers I see are superfical.
    Example; I have spent much time downloading detail tech date; two examples of what I found;
    One manufacture has a 3.5t condenser units, but only lists 3t or 4t "matching" evaporators. Does the installer guess?
    Rheem tech date has 4 3.5t evaps, but no details on what the tech differences are.
    I called the local Rheem distr. he said and I quote, "we always order just one number"
    Now I expect the Reheem units are probably tall, short, std and high effeciency. I would like to know how do I get the one with the most latent capacity. I asked the man about latent btu's and he acted like I was speaking greek. I don't think the correct answer is get a good contractor, pay top dollar and you will by difinition be happy because you paid the most.
    I would just like to get some "sound tech/engr info" I have talked to 4 installers and they don't even agree if you need TVX or a drier installed. The installer recommended by a distributor said he did'nt like TVX's; go figure. And you wonder why the public throws AC guys and lawyers into the same pool. Sorry for the rant, but after hours of diligent work coming up with nothing from the pro's. It's insulting to be told that a Kia is as good as a Lexus if you have a good mechanic!!

    gn
    sorry tried to answer your question,I/We don't handle those brands,and take no responsibility for there information provided.Wish you the best of LUCK.LOL

  12. #12
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    Carnak: how does one dry the outside ambient air to be able to draw in dry air to reduce the humidity in the house?
    The post was from someone on the Gulf Coast = hi humidity ambient, just as here in Huntsville AL where low outdoor ambient humidity equates to something 85% or less ( per the Channel 31 weatherman 2 mo ago).
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,556
    genco, post the model # of the equipment you have been quoted, and somebody here might be able to tell you its specs.
    Contractor locator map

    How-to-apply-for-Professional

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

Page 1 of 4 1234 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