Development of a Mobile HVAC System for Operation with Engine Off

The desire to reduce environmental damage and conserve fossil fuels, as well as current and pending legislation, highlights the need for a truck air conditioner that can be operated when the truck engine is off. Different solutions to this problem have been suggested but the most viable seems to be an electrically driven vapor compression unit. Because of the lack of electrical power when the truck is not running, a practical A/C system must be energy efficient. After a number of studies and tests, a control algorithm to economically match cooling requirements to system capacities has been developed and is under test.