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Thread: makeup air

  1. #14
    Join Date
    Aug 2005
    Location
    iowa
    Posts
    1,649
    but in the end are you trying to save $$$$

  2. #15
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Have you thought of using a De-humidification DOA unit instead of A/C. This type unit uses a desiccant wheel and gas or DX reheat to regenerate the media. Since low temperature is not your goal and you are handling cooling in the space they are more energy efficient than 100% OA DX units. Check out Munters.

    Munters Dry Cool

  3. #16
    Join Date
    Nov 2009
    Posts
    28
    to tell the truth, this is for a new building in africa where I can't find supplier. In addition of that, their voltage is 400V/3ph/50hz. I've tried to contact Greenheck and Reznor to know if they supply out there but no answer.

    This is why I am asking if I can use standard roof top unit by Carrier or Trane which are available outthere. Can their compressor damage at 100% outside air?

  4. #17
    Join Date
    Aug 2005
    Location
    iowa
    Posts
    1,649
    the big problem is that a standard rtu is only designed to handle about 20% outside air. anymore and you will have humidity problems.

    im sure you could oversize the unit and undersize the duct to handle the load, but really that is not my department.

    as far as damaging the compreessors i dont really see how. as long as you had crankcase heaters, tev's maybe hotgas or motormasters.

    basically as long as the unit is set up accordingly it should be fine.

    surely their are international suppliers though? i would think in the big scheme of things our application would be small potatos compared to the rest of the world.

  5. #18
    Join Date
    Jul 2007
    Location
    Mount Airy, MD
    Posts
    7,281
    Threads in multiple locations asking the same question is against the rules

    Should you feel that you have asked your question in the wrong section of the site, report it and ask the Mods to move it for you....

    Threads merged together.


  6. #19
    Join Date
    Mar 2011
    Location
    Louisiana
    Posts
    119
    You could do the duty with an Aaon 100% MUA, takes more than 12 Tons, this is an 18 ton unit

    RN-018-3-0-EB09-000 Cooling Section
    Total Capacity: 210.39 MBH
    Sensible Capacity: 110.55 MBH
    Latent Capacity: 99.84 MBH
    Mixed Air Temp: 98.00 F DB 80.00 F WB
    Entering Air Temp: 98.00 F DB 80.00 F WB
    Lv Air Temp (Coil): 54.83 F DB 54.63 F WB
    Lv Air Temp (Unit): 56.22 F DB 55.19 F WB (not including the HGRH coil)
    Supply Air Fan: 1 x 245D60 @ 1.30 BHP
    Evaporator Coil: 19.9 ft / 6 Rows / 12 FPI
    Evaporator Face Velocity: 125.9 fpm

    Re-Heat Coil: (modulating hot gas re-heat)
    Capacity: 49 MBH
    LA DB / WB: 73.00 F / 61.51 F
    RH: 52%

    However the 400v 50hz power will be a problem

    J

  7. #20
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Again, check out "Munters." They have South African and Sub-Sahara branches.

    I found this unit, it uses a wrap-around heat pipe or energy wheel to help dehumidify and reheat, sizes are available down to 1000 CFM and they have branches in Africa.

    Munters Wringer

  8. #21
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Greenheck has offices in africa as well.

    Greenheck in Africa and Middle East

  9. #22
    Join Date
    Mar 2003
    Posts
    7,321
    munters, deschamps, AAOn, venmar all make units. if you can utilize the lav exhaust, you could use an air to air heat exchanger for energy recovery, with no air coming into contact with the other, otherwise known as ERV. munters HCU are nice, but pricey.

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