chiller outlet temperature

[sethuME]

hi everybody
according to the inside condition,we are calculating the supply air temperature.what is the formulae for find out the supply (chilled)water temperature from the chiller for the supply air from the AHU.say if i get 13 deg C the chilled water temperature is 8 deg C. how?

 

[rogzog]

I may be wrong, but I think that you need the performance data of the coil in the AHU to find what you are looking for.

ROGZOG

 

[Drazen]

I presume that you refer to way the chillers regulate load. Many chillers load controls are arranged in a way that return temperature is maintained, that is if return temperature is set to 11 deg C, when load is small, supply temp. can be say 8-9 degrees. When load rises, supply temp. is being lowered by chiller effort in order to maintain reurn temp.
In that way, on maximum load there will be say 6 degrees supply and 11 degrees return. These are values you neeed (maximal load) to size your AHU heat exchanger.

 

[quark]

First of all you should check what is the coil ADP. Maintain chilled water inlet temp. to coil 1⁰C lower than coil ADP.

 

[HowHVAC]

Normal order of design is as follows:
1) specify room conditions;
2) calculate room load;
3) specify CW supply & return temps (i.e., when designing the CW system);
4) select Fan Coil Unit size by applying the above info to the FCU manufacturer's sizing charts.

If some FCU(s) are already owned, and needed is to build a CW system to suit, then use FCU sizing charts to work backwards to find the needed CW temps. But the FCU is the tail to the CW system (the dog) - be careful that such an approach does not produce an uneconomical CW system.