DX package unit for fresh air supply

[wilcox]

Hi everyone,

I am sourcing some sorts of water-cooled packaged units for supplying fresh air to an air-conditioned workshop (of area around 1000m2 and 6m clear headroom) of a factory premises. The existing air-conditioning units serving the workshop are in good order yet no fresh air is supplied.

My designed fresh air supply rate is about 5m3/sec (estimated by 5 litre/s/m2) for the workshop. Could I use DX package units (say 4 to 5 units) to pre-cool the said fresh air (from outdoor 33.5DBC/65% to 25DBC)? I have heard that the prevailing products in the market could not perform well as the on-coil temperature is so high and hence the superheat conditions would overload the compressors. Is it true? Any advice please?

Grateful if anyone would give me some advice. Zillion thanks in advance.

 

[imok2]

I would say that you are well within the perameters of the average rooftop AC unit, the dew point of OSA is about 80*F db so you will be removing almost as much moisture BTUs as DB BTUs. My guess is about 18000 btu of sensible and about 16,000 of latent(moisture) btu. See what others have to say
OH, and make sure the condensate lines are very big...Just kidding!!

 

[paulkeating]

Make sure you look into the control sequencing - ie what happens to your OA supply temperature when one (or more) of your units is in de-ice mode ......