Heat Transfer Efficiency
Heat Transfer Efficiency
(OP)
There's some debate in this camp regarding the gained (or lossed) efficiency with improving the heat transfer of a constant air volume air handler by cleaning the coil.
Assume a 20-story building with air handlers on every floor and a central plant chiller cooling a cold water loop.
One party claims the central plant chillers would see more load (from better heat transfer) and use more energy. I see it opposite - in that the chiller, over time, would use less energy because of the better heat transfer.
Any opinions on this would be appreciated.
Assume a 20-story building with air handlers on every floor and a central plant chiller cooling a cold water loop.
One party claims the central plant chillers would see more load (from better heat transfer) and use more energy. I see it opposite - in that the chiller, over time, would use less energy because of the better heat transfer.
Any opinions on this would be appreciated.





RE: Heat Transfer Efficiency
At the same time your air handler fans are probably drawing more current trying to push air through dirty coils. Cleaning the coils should save a little fan energy.
The chiller probably won't see much change because like I said your load is your load. I think the real savings is in fan and pump energy. The only way I see the chiller energy going up is if you are not meeting the load now and by cleaning the coils you will. In that case, you are actually transfering more heat.
This is just my "common sense thinking". I would be interested to see if anyone has conducted a study or has actual data on this.
RE: Heat Transfer Efficiency
COP = Effective cooling out/Work in.
I like to think about it in terms of PID in controls, you know, approaching the set point in the shortest possible time... therefor less energy use.
RE: Heat Transfer Efficiency
RE: Heat Transfer Efficiency
If you cannot transfer heat then you have no load. As said "your load is your load". You have nothing working harder, valves are valves and don't have a working load. Pumps don't work any harder in the loss of a heat load transfer. They maintain as they do any other day with a load.(unless you have a building with a pump driven frequency drive)