Using condenser water for hot water coil?

[tikitime]

I am working on a project to evaluate different energy recovery methods for some 100% OA ahu's. One of the suggestions I received was to look at using the condenser water from the cooling tower and a heat exchanger to heat the water for the hot water heating coils. Is anyone familiar with this type of system? I don't understand how it would work when condenser water is typically only 95 degrees at most.

Thanks

 

[mechtech1]

that is used to preheat domestic water or makeup water. It will not do anything for 160-180 degree hot water coils in a closed loop because you don't use much make up water. If you you use alot of domestic hot water you may want to think about that.

 

[quark]

csaskie!

I used that scheme and it is found to be very good. But instead of having one more heat exchanger try to circulate the same water(to do this you should have good quality water). You have two advantages in this scheme. One is you need not have separate energy source for heating water and the second is you are decreasing cooling tower load by cooling the water elsewhere. (I mean in AHU)

The temperature of hot water depends upon how much reheating you required. But in general that is quite a good temperature.

Regards,

 

[VEEKRISH]

Hi Csaskie,

I've done this once. What I've added to the normal system is put in a de-suerheater before the condenser.

This will be a small shell & tube heat exchanger and the water quality in this circuit can be better than what you would expect to have in the main condenser (cooing tower circuit).

The system we used was in a small hotel. Putting in the de-superheater, we were able to obtain hot water at about 80 deg F.

You could also check if you want to operate at slightly elevated condensing temperatures, so that hot water temperature obtained would also be raised. What you need to check is the increased power consumption at higher discharge tempratures vis-a-vis heating bills!