Capture of waste heat to improve pre-treatment drying


Using an existing source of hot water to provide heat for drying significantly improved energy-efficiency at ASSA ABLOY’s manufacturing site in Melbourne.


At ASSA ABLOY’s Oakleigh manufacturing site in Melbourne, Australia, the pre-treatment system for powder coating was inefficient. The final hot water rinse tank, utilizing electrical heating elements, could not achieve the desired 50°C and the pre-treatment line hot air chamber was unable to fully dry the majority of racked components, so parts were diverted to the powder coat curing oven to complete drying.


The solution was to utilize the warm to hot water that flows out of heat exchanger wrapped around the powder coat oven exhaust flue to supply hot water to the pre-treatment line final hot water rinse tank. When the powder coat oven burner is on a high setting, minimal gas is consumed by the gas hot water service.


After the equipment was installed the parts processed through the pre-treatment line exit were fully dried, eliminating need for secondary drying. The calculated electricity saving is 76kWh per day through removal of heating elements; however, there could also be energy savings associated with having less volume through the oven which would more than compensate for the increase in energy required for the water heater. The upgrade also enabled the weekday overtime to be reduced by two hours per day and by one day of weekend overtime monthly.