INVISOR UNDERWRITING SERIES

In small-scale production, the installed cost of the system, including solar collectors and backup, is estimated to be about $10,000 greater than a conventional heating and cooling system, and a much lower cost should be possible in the longer term. With 25 square meters of evacuated tube solar collectors, the CaCl/sub 2/-CH/sub 3/OH chemical heat pump should be capable of meeting over 90% of the cooling load, 80% of the heating load, and 70% of the domestic hot water load with nonpurchased energy in a typical well-insulated single family residence, thus saving about $600 per year. a detailed performance and economic analysis was carried out for a system operated in Washington, DC. The minimum practical hourly rate, 0.10 moles CH/sub 3/OH per mole CaCl/sub 2/, was observed with the salt-bed heat transfer fluid at 40/sup 0/C and the CH/sub 3/OH evaporator at -15/sup 0/C. The experimental rate of CH/sub 3/OH absorption is a strong function of the absorber-evaporator temperature difference. This has been confirmed by direct experimental measurement on an engineering development test unit (EDTU). A detailed thermal analysis shows that the coefficient of performance for heating is moreВ В» greater than 1.5, and for cooling, greater than 0.5. It combines all features required of a residential or commercial space conditioning system except for solar collection. Such a system is capable of storing heat indefinitely at ambient temperature, and can be used for space and domestic hot water heating, and for air conditioning with forced air (dry) heat rejection. 2CH/sub 3/OH can be used as the basis of a combined solar heat pump/thermal energy storage system. The reaction of CH/sub 3/OH vapor with solid (pellet) CaCl/sub 2/ to form the solid phase compound CaCll/sub 2/. Furthermore, SAHP systems are not currently cost effective when compared to standard air-to-air heat pumps, nor is there evidence that they will be in the foreseeable future. Since all components for solar-boosted heat pumps are now commercially available, no further development work is needed to optimize the heat pumps for such a system. The results of this study indicate that solar-boosted heat pumps (parallel) will be more cost effective than solar-assisted (series) heat pumps for the foreseeable future. A marketing analysis is performed to assess the potential of SAHP systems in the residential marketplace. Ground coupling, evacuated tube collectors, and power demand distributions are studied. Material and installation costs are obtained for the SAHP components and are used in a life-cycle cost analysis to determine the economic viability of moreВ В» the various systems. Performance characteristics of all major SAHP components are determined and used in conjunction with the TRNSYS simulation program to obtain heating and cooling system performance for four different climates: Phoenix, Arizona New York, New York Fort Worth, Texas and Madison, Wisconsin.

INVISOR UNDERWRITING SERIES

The series (solar-assisted), parallel (solar-boosted), and standard heat pump systems with electric resistance heat backup are emphasized. Phase I of this study deals with the determination of the most cost-effective SAHP (Solar-assisted Heat Pump) system.

Invisor underwriting