Hot water is critical in a variety of commercial and industrial applications, but producing hot water can be expensive. Recovering waste heat is an effective way to help reduce the cost of heating water.
A tremendous amount of heat is exhausted from the combustion process of hot water and steam boilers. One way to capture that heat is through exhaust gas coil or tube air-to-water heat exchangers. The heat can be used to raise the boiler feedwater’s temperature, or for other uses, such as process heating or space heating.
One equipment manufacturer found the following cost and savings results from implementing heat recovery in a variety of applications.
Results vary depending on the situation. For applications with at least 21 gallons per minute of hot water flow, 1765 cubic feet per minute of exhaust gas glow and a minimum stack temperature of 392°F, a stack temperature reduction of 100°F can result in a simple payback of less than two years.
Recovering exhaust gas heat also allows boilers to respond more quickly to rapid load demands due to higher initial feedwater temperature. For steam boilers, it reduces the chance of thermal shock. For every 40°F to 50°F drop in stack temperature, a 1% gain in boiler efficiency is realized.
Work with a trusted equipment supplier to determine if hot water heat recovery is right for your application.