Drying and curing ovens - paint, powder-coat, converting, and food baking - operate between 80 and 250 C and exhaust continuously, wasting large thermal loads. Because the exhaust is hot and relatively clean, a great deal of that heat can be recovered rather than vented.
Plate heat exchangers or heat pipes recover sensible heat efficiently to preheat combustion air or make-up air. Where the oven exhaust is dry, a rotary wheel can also recover moisture, which is useful for ovens with integrated humidity control.
For solvent-bearing ovens, route the exhaust through a regenerative thermal oxidizer (RTO) and recover the oxidizer's heat; never send solvent-laden air through a rotary wheel that could accumulate VOCs. Respect ATEX and explosion-protection norms for any combustible off-gas.
Size the exchanger for part-load as well as peak, include a bypass, and manage condensate if make-up air is cooled below its dew point. Savings of 20-50% of oven fuel are typical, with faster warm-up and steadier temperature profiles that also improve yield.