A proposed apparatus would provide or augment cooling or heating of the interior of an automobile in the presence of sunlight. The apparatus could be added to an existing automobile, with little or no modification. Utilizing solar power, it would operate independently of the automobile engine. Hence, for example, it could augment the direct solar radiant heating through the windows of a car parked in a sunny location on a winter day, perhaps making it unnecessary to keep the engine running to maintain warmth.
The apparatus would include a solar photovoltaic panel mounted on the roof and a pane-llike assembly mounted in a window opening. The window-mounted assembly (see figure) would include a stack of thermoelectric devices sandwiched between two heat sinks. A fan would circulate interior air over one heat sink. Another fan would circulate exterior air over the other heat sink. The fans and the thermoelectric devices would be powered by the solar photovoltaic panel. By means of a double- pole, double-throw switch, the panel voltage fed to the thermoelectric stack would be set to the desired polarity: For cooling operation, the chosen polarity would be one in which the thermoelectric devices transport heat from the inside heat sink to the outside one; for heating operation, the opposite polarity would be chosen.
Because thermoelectric devices are more efficient in heating than in cooling, this apparatus would be more effective as a heater than as a cooler. However, if the apparatus were to include means to circulate air between the outside and the inside without opening the windows, then its effectiveness as a cooler in a hot, sunny location would be increased.
This work was done by Richard T. Howard of Marshall Space Flight Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Machinery/Automation category.
This invention has been patented by NASA (U.S. Patent No.6,662,572). Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to
MSFC Commercialization Assistance Lead
Refer to MFS-31751-1.