large system de-superheater

[jheffernan]

Hi,

I'm wondering if anyone as any experience using water-cooled de-superheaters to generate hot water/supplement condensers. It seems a good idea but I wonder about drawbacks.


Jim Heffernan

[Nico]

Hi Jim,
I don't know any system using water cooled de-superheaters for hot water generation. The reason is that there is little heat to gain from de-superheating. There are lot's of systems using water cooled condensers for hot water generation -sometimes in combination with air-cooled condensers- whereas a lot of heat is available andthe superheat can give just a little extra temperature gain. Water cooled de-superheaters are used sometimes when there is altitude difference between the receiver (low) and the expansion valve (high), or when the liquid piping has to go to a far place through hot area. In commercial systems you find watercooled de-superheaters when a booster pump is used and the designer wants to prevent cavitation in the pump (look at http://www.fridgetech.com/discussions/).

[joscon]

Yes, we use plate & frame / flat plate heat exchangers all the time. Mostly for floor warming in Lg. freezers W/ concrete floors.

[Edited by joscon on 11-06-2001 at 03:56 AM]

[jheffernan]

Good point about how little proportional heat is in the de-superheating.

I'm running a sysytem that requires about 300 HP (rotary screws) to run a 28psig suction with 110psig discharge. My discharge temps are 160F. My thinking is this converts to about 250 tons.

250 tons converts to 3,000,000 BTU per hour? De-superheating accounts for say 6% of that? 150,000 BTU could heat 2,000 pounds of water 75 degrees, say 225 gals an hour.

Does this seem right, or do I take a wrong turn of logic somewhere?

Jim Heffernan

[kherne]

There are desuperheaters being made using water to ***** to water, ul listed as refrigerant heat reclaim units, desuper heater is not an actual term slang only,
see aquachillers.com we rep them in maryland and va. good luck, Ken

[C. Noseworthy]

We use Plate & Frame, Vented tube in tube and jacketed tank type desuperheaters in almost every skating rink we build. These are typically 200 to 400 kW ammonia systems. Check web sites for Doucette Industries and Thermastor.