Auxiliary Power Units (APUs) are used in the transportation industry for supplemental power on vehicles, ships, aircraft, tanks, trains, trailers, and even spacecraft. The power provided by an APU is supplemental to a transportation device’s main power source and is typically engaged when the main engine is not being used. An APU can have a single purpose or multiple purposes depending upon the application.
APUs are frequently used to power onboard climate control. As part of the system, there will be an air heater to warm the cabin. The air heater will contain one or more electric heating elements. APU heaters are designed to work within the power requirements of the auxiliary power electrical system. Other design considerations include air-flow, heating element temperature, safety, and physical dimensions. Tutco-Farnam designs and builds APU heaters for heating air in an APU climate control system.
Long-range commercial trucks use Auxiliary Power Units to reduce engine idling. When a commercial truck engine is not running the APU can regulate climate control and provide onboard power. It will keep the engine warm and regulate air temperature in the sleeper cabin. It can also keep the batteries full while providing power to lights, radios, and outlets.
Engine idling has a fuel cost as well as an environmental cost. Anti-idle laws and APU exemptions exist to curb greenhouse gas emissions. Commercial operations are motivated to invest in APUs for their long-range vehicles.
Auxiliary Power Units on aircraft are used to start the main engine. When sitting at a terminal, APUs can power lights, regulate cabin temperature, and supply power for the preflight checklist. Special high altitudes APUs can provide backup power if an engine fails.
The preceding examples are liquid fuel-powered APUs. Batteries and Solar Cells are also used for auxiliary power where the power demands are small. An airplane APU used to start the engine will need to pack a much bigger punch than a solar APU on a camper.
Tutco-Farnam has decades of experience designing and manufacturing electric air heaters for temperature and humidity control devices. Contact a representative with your unique project requirements and see what Tutco-Farnam can do for you.