Certain processes require a closed-loop (or closed-circuit), whereby, the process water for cooling does not come in contact with the atmospheric air. This prevents the cooling water from picking up particles that may not get filtered or even dissolved gases. Closed-loop cooling requires more energy and has higher initial and life-cycle costs than an open cooling tower, but provides an added protection to expensive processes or chillers being cooled.

	Cooling Tower plus Pumping Skid
	with Dual Plate&Frame Heat Exchanger

For closed-circuit cooling Delta recommends a cooling tower plus a plate heat exchanger system. The skid-mounted plate heat exchanger provides a closed-circuit on the hot side of the heat exchanger. The non-corroding Delta cooling tower feeds the cold side of the plate heat exchanger.

The advantages of this system over a closed-circuit cooling tower (usually galvanized sheet steel and galvanized steel coil inside a cooling tower box) are:

· Typically Costs Less
· Less Total HP required
· Delta cooling tower has 15-Year casing warranty versus 1-Year
· Expandability – Heat Exchanger can handle future load increase by adding plates
· Maintenance – Heat Exchanger has Stainless Steel plates and is much more accessible than coil for easy cleaning
· Weight – Delta tower is 3-7 times less weight saving rigging and structure costs
· Install Flexibility – Heat Exchanger skid can be placed indoors without need to maintain Glycol solutions necessary with outdoor coil
· Water treatment easier and much less risk with Engineered Plastic Cooling Tower.
· Galvanized steel coil replacement cost (labor and material) often exceeds initial unit cost of Closed Circuit Cooling Tower. Corrosion is only delayed with galvanizing and wet/dry operation, chemicals, PH fluctuations, salts and other atmospheric conditions can lead to premature failure.