How heat recovery is managed in paint booths
Maintaining the optimal temperature set point for paint application is highly energy consuming. The use of heat recovery systems in painting processes can drastically reduce the costs of air heating and cooling, reducing the environmental impact of the processes and guaranteeing a fast payback, even lower than 1 year.
By Luca Brotto, Application Manager- Industrial HVAC, CAREL
The choice of the right heat recovery unit depends on the air flow-rates involved, the heat exchange efficiency, the risk of contamination between the air streams, and the related planned preventive maintenance. Let’ s see how the heat recovery inside spray booths is managed. The heat exchanger is placed between the supply and exhaust air streams, as displayed in the following schematic layout. Depending on the outside environmental conditions, this heat exchanger can have a heating or cooling effect on the incoming air: in winter, the outside air is at a lower temperature( for example 0 ° C) than that required in the booth( for example 22 ° C); the heat exchanger thus heats the outside air by taking heat directly from the warmer outgoing exhaust air, without consuming energy and without mixing the streams( for example, a heat exchanger with an efficiency of 50 % brings the incoming air to 11 ° C). Conversely, in summer the outside air is at temperatures higher than the set point: inside the heat exchanger, heat flows from the warm incoming air to the colder outgoing exhaust air, thus cooling the incoming air flow, without consuming energy. The most widely-used heat exchangers in air handling units for painting processes are plate heat exchangers and thermal wheels. In specific cases, run-around coils are also used. The choice between the different technologies depends on the characteristics of the paint booth and the process, including the air stream, dimensions, operating hours, efficiency, maintenance requirements, ease of cleaning and also the type of paint used.
54 Heat Exchanger World October 2026 www. heat-exchanger-world. com