Announcement

**Johnson_Thermal** · 04-15-2015, 11:00 AM

In theory, this is no problem.

Practical Issues:
-Availability of the Draft Tower unit in a water cooled configuration. Conversion is possible, but you would need someone who knew what they were doing. Or at least EPA licensed to handle refrigerant.
-Most water cooled systems are setup expecting 75-95F condenser water. As you are running cold water through there, you could in fact "overcool" and have the same problem as an air cooled unit on a cold winter day. This can be dealt with by limiting the flow to unit by throttling or bypassing. There are other methods to make this work that might be "better" but are more complicated.
-Probably lots more that I can't see from here!

To reiterate, this idea is not out of whack. We have in fact built built several systems that were water cooled by other chiller systems, but albeit for other reasons.

As I understand it, the draft tower unit is air cooled and in an unconditioned and hot space. Ducting outside are in and out is not possible/practical. Maybe this would work; hang a small fan coil in the attic, and use your "extra" chiller capacity to keep the space cool, or bolt it to the front of the condenser on the draft tower unit (so you aren't cooling the whole space). May seem hokey, but you are doing the same thing; rejecting heat into the roof mounted chiller.

Have fun!

Jeff

**Starcat** · 04-15-2015, 11:58 AM

Condensing Media

Your conjecture is very UNCLEAR.
If you are wanting to use glycol to supply a water cooled condenser which would be retrofitted in place of an air cooled condenser on a draft line chiller, NO because a water cooled condenser is not designed for cold glycol as the media. And yes you do not want the entering condenser air of your power pack unit to be over 95F or you are asking for problems. If you have a cooling tower, yes you can operate additional water cooled condensers on that if you have the correct pump and valve arrangement to run it.
You also do not want to use your Brewery glycol loop for your draft system because you need a constant temperature for draft service.
Air cooled condensing units don't belong in attic or unventilated spaces. One option is to ventilate mechanical rooms with evap cooled air in a situation such as yours.
A glycol power pack could be retrofitted with a remote condenser but there would seem to be much better soultions possible in such a case.

**whaleyproducts** · 04-24-2015, 09:45 AM

Glycol to Glycol Heat Transfer Skid

Chadgregory87,

The water-cooled chiller idea would not work with a 20F to 40F glycol serving the condenser side of the water cooled chiller. Operating at low condensing temp will make your condenser pressure fall at a very low level. Since the operation of the TXV relies on the pressure differential of the low side and the high side, if the condenser pressure is low, the TXV will not work properly. The excessively low condensing pressure will reduce the refrigerant flow rate to a point where evaporating pressures can fall to a dangerously low level, and can result in evaporator frosting, compressor short cycling, liquid refrigerant floodback and other malfunctions; all of which can lead to compressor failure.

However, a much simpler solution (if your outdoor glycol chiller's outlet temp is lower than your new cold room glycol temp will need to be) would be to use a heat transfer skid with 3-way on/off control valve to divert the chilled glycol through the heat exchanger when the hot side was calling for cooling, and divert it away from the heat exchanger when the hot side was not calling for cooling. You could put a tank, pumps, and a glycol to glycol heat exchanger on the skid with the control valve, etc. Here's a diagram and photos of some skids we build like this, and a link to the sub-page on our website regard.

http://www.whaleyproducts.com/heattransferskids.htmlhttp://

Another option would be to simply run your glycol a little colder on your existing oversized chiller, and install an indoor fan coil unit in your cold room with a 2-way solenoid valve installed on the fan coil. We offer this option as a package. You can get a vertical unit (installed on the ground), or a horizontal unit (installed up in the upper corner of the room off some uni-strut from the ceiling.