Water Cooled Condenser-Cold Condenser Water
I am working on laying out a system for meat cutting plant. Everything is mostly old crap that is falling apart. The aging room cooler and drip cooler room have evaps pulled out of rail cars.
I am looking at putting in a 40 HP chiller for their aging room, drip cooler, and cutting rooms. They want to add a couple of cooler rooms. They are all to be held @ 36 F.
They also want to add a couple of freezers that they are going to keep @ -10F. I would like to use water cooled conednsers and run the glycol loop for the condenser.
The condenser water will be 25 F or so. I am concerned about the water regulating valve hunting with such cold water. Even if I sqaure that away will such a low flow/ high delta cause some kind of problems? Still working on the size but will probably be a 5HP or 10 HP. If it is a 5HP is will be a hermetic with a COAX and the 10HP will be a Discus with an S&T.
Any input would be appreciated.
If the regulating valve is sized properly, most likely undersized, I don't see a problem with hunting. If the reg valve works properly I do believe the rest willl work fine. Coldest I have seen is 35F on the reg valve inlets and had no problems.
To much work with too little time!!!!
Originally Posted by clydemule
If your entering condenser water temperature is 25 F, the manufacturer of the equipment will need this information so they can design the condensers accordingly. The standard design conditions for water cooled condensers is 85 F EWT. Water entering at 25 F would increase the subcooling which would increase the capacity of the unit about 30%. This will affect the TD across the coil, TEV sizing, evap sizing etc. etc etc. If you don't have the equipment designed for these conditions be prepared for problems. In fact, go ahead and keep an extra compressor on the job.
I designed a -30 blood freezer job in Orlando where 45 F chilled water was used for the condenser. The S/T condensers that the manufacturer used were smaller than the normal for 85 EWT. The pumps and chiller did fail once, which caused higher temps due to the EWT rising to 85 F. But it's hard to make it perfect for a 40 TD EWT and you have a 60 TD EWT.
Your design criteria depends on the 25 F EWT, can that be guaranteed all the time? You might look at the option of using smaller HP units which would pump more BTU's at this lower EWT. But, once you have determined the BTU's that are required, have the refrigeration equipment manufacturer work out what is best.
Last edited by powell; 12-11-2007 at 01:43 PM.