Approaches that increase the coefficient of performance of refrigerator systems are sought constantly. Recent interest has been directed toward the use of heat pumps for refrigeration and air conditioning because they have shown promise in increasing performance and lowering operating costs. One heat pump system that has shown great potential is based on the absorption and desorption of hydrogen from metal hydrides. In this system, a low temperature metal hydride is coupled to a high temperature hydride, pemitting energy to be extracted from the surroundings. A major advantage of this system is that these heat pumps operate without any moving parts, using hydrogen as the working fluid in a closed cycle that can be repeated indefinitely. Performance can be increased in these thermally driven heat pumps during two instances when the heat generated during absorption of hydrogen by the metal hydride must be rejected. In both of these instances, the rejection of heat by means of an innovative scheme will increase the rate of the absorption process. In addition, this process can greatly reduce the amount of energy that must be supplied to raise the low temperature hydride to re-start the cycle. Consequently, the heat pump's over-all performance is improved, making it more competitive with standard refrigerator and air conditioning systems. The objective of Phase I is to demonstrate that a substantial increase in the operational efficiencies of refrigerator heat pump devices can be obtained using an innovative subsystem in conjunction with two metal hydrides.Anticipated Results/Potential Commercial Applications as described by the awardee:A successful Phase I program will demonstrate that the process of energy storage, as well as the storage of large quantities of fuel in hydride systems, can be greatly improved by increasing the efficiency of the hydrogen absorption and desorption cycles. This improved efficiency will make the use of hydriding pumps in mechanically driven systems more attractive from a cost-competitive stand point. Consequently, opportunities in such diverse markets as refrigerators, air conditioners, automotive engines, and off-peak electric storage appliances are greatly enhanced.
