In the long-haul transportation industry, truck cabs are not only workplaces but also mobile residences for drivers. When the vehicle is parked and the driver needs to rest, maintaining a comfortable temperature inside the cab becomes a pressing issue. Traditionally, drivers often let the engine idle to power the vehicle's air conditioning, but this method is not only fuel-inefficient and produces high emissions, but also increases engine wear and noise pollution. In recent years, a specialized air conditioning system designed for parked vehicles—parking air conditioning—is quietly changing the industry landscape.