I need to dehumidify the closed room by controlling chill water supply to ahu?

Question

i need to the rh in a plant with in 55%

Answer 1

To control humidity in any room, you need to do a few things first.

Evaluate the room and all openings. Controlling the indoor environment is only as easy as the way the room is built. For tight environmental control you should think about a vapor barrier around the room (walls, and ceiling). This way once you dehumidify the room, you are also minimizing other sources of water vapor entering the room.

55 % RH is not that low. Use a chilled water cooling coil to dehumidify the room supply air. Control the cooling coil valve not with the room temperature, but with the return air RH.

If the AHU is supply more than one room the cooling coil control valve should be controlled to maintain set discharge air conditions (dry and wet bulb temperatures). You will be able to ensure that the room in question is getting enough dehumidification. You may end up overcooling other rooms served by this AHU.

It may be better to serve this room with a dedicated unit.

Answer 2

like a car air conditioner - pass the room air over the chilled water line, collect the condensation, and drain it from the room. ever see the water below a car when the air conditioner is running?