Capturing Waste Heat With Ultra-High Efficiency
Crawford Equipment & Engineering Company of Orlando, Florida offers a complete line of services related to industrial process heating equipment, including design, fabrication, and sales. With their diverse capabilities, they regularly find uses for Munters air-to-air heat exchangers in their designs. The company recently installed a unique two-stage system for a well-known automotive parts manufacturer at a plant in Ohio that fabricates headlight lenses.
One of the processes in the plant involves applying a chrome coating to the lenses. A thermal oxidizer incinerates isopropyl alcohol and the butyl acetate fumes that result. A Munters model S81CF Thermo-Z™ heat exchanger recovers heat from the incinerator’s exhaust at 1400°F, so it can be used to preheat inlet effluent air from 123°F to 1180°F. In doing this, the heat exchanger operates at an almost-unheard-of efficiency of 83%.
In the second stage, also supplied by Munters,
a water coil in the exhaust stream uses 365°F
air coming out of the heat exchanger to heat a water-glycol mix from 160°F to 190°F. The water then flows to a cleanroom in the plant, where a forced air fan blows ambient air across a second coil, heating the air from 70°F to 180°F. This hot air goes to a flash-off zone, where it cures a sprayed-on clear coat and solvent applied to the lenses. Using waste heat from the thermal oxidizer to heat water in this fashion eliminates the need for a boiler.