Recirculating Coolant Loop?

Well I have not installed a recirculating cooling system for a screw compressor, but I did for a few other pieces of equipment for exactly the same reason -- we were dumping thousands of gallons of water down the drain every year.

You need to measure the temperature difference between inlet and outlet as well as the flow rate (it easier than using tube sizes and water pressure). When that's known, you can calculate how much radiator volume and surface area you need to use with forced air cooling (similar to the cooling system on your automobile) based on manufacturers' ratings for their wide variety of cooling coils.

Any HVAC engineer can help you with sizing once you know the temperature differences and flow rates and the desired operating temperature of the compressors.

There's a well-known formula in thermodynamics: Pv = nRT for pure gasses, but it's not far off for air. From that and the pressure in your air tanks, you may get a handle on how much temperature rise you have just due to compression of air. The efficiencies of the mechanical portions of your compressors will tell you how much more heat is added. e. g. 85% efficient 50 HP compressor => 15% of 50 HP heat.

Doublr_j_b Just a few thoughts to add to your list of options, I had a line of high speed machinery that had two areas where the temperatures needed to be maintained to a specific temperature to operate correctly. We installed a portable chiller on each module. These chillers had a tank filled with a solution of water, antifreeze and chemicals to control algae & other undesirables (around 25 gallons). On top of each tank was a cooling unit with copper coils extending into the tanks. We were able to control our machine temperatures by pumping this solution through cavities in the machine and returning it to the tanks. The chiller thermostat was used to control the temperature and the pump ran full time. We were able to freeze the condensation on the machine if the units were set to low. These type units are available in a number of sizes and capabilities. Another option would be to use the ground as your heat transfer medium instead of the air, it remains more stable year round and would require less power than the chillers. Either run your pipeline down to the ground water and back or bury them in a grid. The temperature could be controlled by the pump speed re circulating the fluid. Any reputable heating and cooling company can handle all the calculations & installations nowadays. It would be ideal if you could use this heat in your cold Oklahoma winters to some advantage like heating your or some other structure rather than being wasted. J.Conway

Quincy Screw Compressors do not necessarily need to be cooled with water. I am sure you are pumping water through a heat exchanger and your oil or (coolant) is the other part of the equation.

You can very easily adapt your units to another Quincy option that uses an air over exchanger to cool the oil.

All things considered, this would be your best option. You could even re-pipe the system and re-locate the air over exchanger some where else if need be with little or no consequence.

Tim, down in Mexico

I like you thinking there Tim but unfortunately the compressor itself is kept in the boiler room. So not a lot of cooling is going to happen there. I am interested in what you are saying about it being possible to locate the cooling system apart from the compressor itself.

Could you explain this a bit more?

Try to think about the cooling system in your car. The engine creates heat that is removed by circulating hot water from the engine to the radiator, which has cool air blowing through it to cool the water off again. But there is also a heater core that is plumbed parallel to the radiator.When you allow water to flow through the heater core, the air that you blow through it will warm up the inside of your car.

In your installation, the compressor is your engine, or heat generator. By burying enough pipe under the ground, the heat will be given up to the cooler ground. But if you were to run another section of pipe into a room, it would be able to warm up that room. If you run the second pipe run parallel to the underground pipe, you can install a shut off valve in the room heater to allow the room to stay cooler in the warmer seasons. Hope this is clearer now.

I like that! I may have to try and figure a way to make that work at home.

Send me the correct model designation of your units and I can offer a good explanation.

Thanks to all who have replied thus far. The information you provided is very helpful. I am also curious as to how long the payback was on the installations you have had experience with. If you could pop me that info I would be greatful.

I like the idea of using the ground temps to do the cooling. Sounds like a feasible solution as well.

Call a reputable boiler supply house. They can size a small hydronic fan/coil unit that will cost very little to purchase and install. Since it is a closed system, you will not need to treat the water.

There's generally speaking no water involved if you are to use a fan/coil unit on a Quincy. They are generally set up to cool the oil. But if we could get a specific model number, a better answer could be given.

Sorry for the delay I am trying to get the information you requested, however i have spent the last 5 days clearing sidewalks and have had my hands full.

Just a short reply to let you know where I am at but I can tell you that both units are nearly identical in that they are both a QSB style compressor with the water cooled option. One is a something like QSB 50 WC and the other is QSB 25 WC.

I will try and get exact model numbers when I get a bit more time.

Thanks for being patient.

No problem, just trying to help. As you stated "with the water cooled option" . I'll dig up some details now that we know they are in fact QSB's

So if you had run this recirculating coolant loop during the summer, you would not have to be out there clearing the sidewalks now would you?

Ha Ha Ha good one, everyone wants to be a comedian huh?

ok ya got me there but i think that the excavation required to run the loop under the walks would extend the roi on the system out for quite a long time.

I'm having a hard time getting any specific drawings or parts lists with out specific serial numbers (typical these days).

But I have found that the standard quincy air cooled design will work well in ambient temperatures up to 115F.

On many of the rigs we install standard ventilation type duct work over the air over coolers to direct the displaced heat out of the machinery spaces as well.

I'll keep trying to come up with some drawings to clarify this, but it seems simply returning your equipment to its "standard" design would be your most reasonable approach to the problem.

At some point this morning I need to attend some projects.

But here is a link to a dealer I have dealt with in the past for Quincy products, http://www.mckenzieequipment.com/

When you open this you will see a standard unit set up. Its larger than yours but the same principle applies.

As you may be able to see, a fan is under the exchanger that blows upward thus cooling the oil.

I see what your talking about and I think it would work fine but definately would have to be used in a remote situation. the biggest problem being that it gets around 140 degrees in the room that the compressor is in now.

Double_j_b You have not mentioned this room temperature as being a problem but I believe you need to address this to. 140 degrees is a bit high and you should increase ventilation to bring this temperature down. This will have a direct effect on your machinery temperatures also. J.Conway

In looking at the picture in the website, It occurs to me that an easier solution might be to build some ductwork from the area above the fan cooled radiator, to bring the heated air directly to the outside. Remember to allow at least as much cool air to enter the room.

Thanks for all the help with this guys I have been looking into the situation and gotten quotations on the various ways to resolve the issue. However the boss has put the squeeze on everything now and the project is on hold indefinately.

Thanks again for the brilliant suggestions.