This cooling system is suitable for about 2KW intermittent heat removal. I have had this cooling system in service for 4 years without any problems. The coolant is distilled water since it has very low conductivity. There has been discussion that it should also be de-ionized. The water should be changed every 3 months because salts released from the metals will increase the conductivity over time. Any corrosion inhibitor added must have very low conductivity.

The tank is made from 6” PVC pipe with end-caps. Top can be removed for changing the water. It is mounted vertical to keep smallest possible water area exposed to air since oxygen will increase corrosion rate.

Use a 200 gallon per hour magnetic drive plastic pump to compensate for pressure drops in cooler and lines. Suitable pumps can be found at Graingers. The cooler is a generic aluminum transmission cooler that can be found at any auto-parts store. The cooler can be placed in the supply or return flow path. It will be most efficient in the return path because of a bigger temp difference between water and air. The drawback is that the water-line pressure is higher because of pressure drop in the cooler. A quiet generic 120mm muffin fan is mounted on the cooler. It can be controlled by a thermostat if desired.

NOTES: All flexible water-lines are standard 3/8” clear vinyl hose from the hardware store. The water lines should be grounded 24” or more from the tube. This is done by stainless tubing or hose barbs connected to the chassis. The water return should enter the tank below liquid level to avoid mixing in air and minimize agitation. A flow sensor can be added in the return path and interlocked with the amp to guarantee sufficient flow to operate the amp. Vinyl hose is very flexible so make sure there are no kinks that will stop the flow. Use all plastic or stainless pipe and fittings to minimize water contamination.

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