3 replies to this topic

[RAMSAI]

We are Handling AHU's Supplied by Chilled water temp which goes to chilled water inlet at 9 Degree Centigrde and the desired flow is maintained. We also supply Hot water at 80 degree centigrade to hot water coil as per the flow requirement.

Now In order to maintain the Temp conditions inside the room 25  degree centigrade and RH less than 55 %.

What shall be logic that is sequence of operation for chilled and hot water control valve .

 

Need your help to understand the logic to be implemented for chilled and hot water control valves so it save energy and system works efficiently.

 

Most of the Net search resulting in keeping the chilled water control valve open until temp and RH is achieved under this situation i observed the chilled water valve remains constantly open even though temp is going below 20 degree centigrade and hot water is opening to increase this temp  to maintain the limit of NMT 25 degree centigrade .Where as i believe the chilled water shall control the temp and hot water control vlave shall be operated for RH only.

 

[Pilesar]

As I understand it, the chilled water is to control the relative humidity and the hot water is to control the temperature in air handling units. There is no way for the hot water circuit to change the amount of water in the air. The chilled circuit can remove water from the air through condensation. The units I am aquainted with always have hot water flowing even during hot summers. 

[snickster]

 Dehumidification Control.pdf   1.72MB   17 downloads

 

Attached is from Honeywell Gray Book controls manual.  The entire manual can be found at this link:

 

77-E1100 - Engineering Manual of Automatic Control (av8rdas.com)

 

 

 

 

[RAMSAI]

Thank you