Dehumidification Design

[sfxf]

The project I am working on requires both temperature and humidification control of the design space. The indoor dry buld temperature is to be maintained at 68 F, and the relative humidity is no higher than 40%. As per the Psy. chart, the maximum supply air temperature has to be around 42-43 F to meet the requirement. I assume sensible load is 75% at this point and reheat coil is needed to increase the supply air temperature from 42-43 F. My question - the 42-43 leaving air temperature doesn't sound too low to be reasonable to me. Does it applicable? If not, anyone can offer me some suggestion? Your help is highly appreciated.

 

[ChasBean1]

sfxf,

You're right on. Cool the incoming air to 42-43 and you should be good under all conditions, assuming the volume of incoming air is able to handle and outweigh the humidity generation rate in the space... Keep on that thought track. -CB

 

[sfxf]

ChasBean1,

Thank you for advice.
I found out later the available chilled water supply temperature was 45 F. There is no way to cool the air down to 42-43 F with 45 F chilled water. I suggest to add desiccant wheel on air handling unit to meeting the humidity requirement.

 

[SAK9]

sfxf;

The only possible options for 40% RH is:

a)Use a brine cooled coil

b)Use a dessicant wheel dehumidifier

cheers