Reduction of Thermal Load in Passenger Compartment - CARAT Phase I Final Report

Life Enhancement Technologies, Inc. (LET) is the leading company in the field of microclimate thermal management technology. Originally designed for cooling astronauts in extreme conditions, systems developed by LET are a direct spin-off from NASA technology. LET's patented technology protects individuals in a host of conditions ranging from extreme heat stress to simply maintaining a desired temperature. LET has modified and refined this adapted technology for applications in the medical, military, industrial, and consumer industries. While participating in the CARAT program sponsored by the Department of Energy, Life Enhancement Technologies developed a prototype using Flexitherm{trademark} liquid cooling/heating panels built into an automobile seat. The prototype is known as the Microclimate Seating System (MCS). Flexitherm{trademark} is a closed loop liquid heat transfer system made of a thin, flexible, conductive material, which transports fluid to provide cooling or heating. Through the use of Flexitherm{trademark} panels, LET is able to provide cooling or heating to individuals or objects it comes in contact with. A delivery system containing a pump, chiller, heater and reservoir was built to deliver the liquid to the panels. The liquid flowing through the Flexithermm is cooled or heated through LET's controlled delivery system, thereby enabling the direct conductive cooling/heating of the passenger. The prototype demonstrated the positive effects of cooling and heating on a passenger sitting on an automotive seat containing Flexitherm{trademark} panels. The air conditioning heating systems as currently used in automobiles are based on high airflow, as well as temperature and humidity reduction to provide thermal comfort to the occupants of the automobile. Air is a very poor thermal conductor. Consequently, high airflow is required and the primary means of cooling is insensible water loss (evaporation). The larger thermal mass of a car and the solar load imposed can result in an 15-20 minute delay in reaching a comfortable thermal environment, despite the fact the evaporator temperature of 60 F or less is reached within the first 5 minutes of operation. Thermal comfort is the absence of thermal stress. The purpose of Phase I CARAT Program was to develop the background material necessary to begin prototype development of a liquid conductive Heating/Cooling system with liquid Flexitherm{trademark} heat exchanger panels integrated into the car seats, thereby enabling the direct conductive cooling/heating of the driver and passengers and also reduce engine power requirement, size and weight. This would improve fuel consumption and reduction of emissions