but in the end are you trying to save $$$$
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
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?
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.
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You could do the duty with an Aaon 100% MUA, takes more than 12½ 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 ºF DB 80.00 ºF WB
Entering Air Temp: 98.00 ºF DB 80.00 ºF WB
Lv Air Temp (Coil): 54.83 ºF DB 54.63 ºF WB
Lv Air Temp (Unit): 56.22 ºF DB 55.19 ºF WB (not including the HGRH coil)
Supply Air Fan: 1 x 245D60 @ 1.30 BHP
Evaporator Coil: 19.9 ft² / 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 ºF / 61.51 ºF
However the 400v 50hz power will be a problem
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.
Greenheck has offices in africa as well.
Greenheck in Africa and Middle East
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.