Thermal Storage for Solar Cooling Using Paired Ammoniated Salt Reactors. Final Report

摘要

The objectives of the program were to investigate the feasibility of using various solid and liquid ammoniates in heat pump/thermal storage systems for space heating and cooling. The study included corrosion testing of selected metallic and non-metallic specimens in the ammoniates, subscale testing of the candidate ammoniates singly and in pairs, trade studies and conceptual design of a residential system, prototype testing, and ammoniation/deammoniation cyclic testing of manganese chloride. Results of the corrosion testing showed that problems exist with manganese and magnesium chloride ammoniates, except with the teflon which displayed excellent resistance in all environments. Also, all liquid ammoniates are unsuitable for use with uncoated carbon steel. Cycling of the manganese chloride between the high and low ammoniates does not affect its properties. However, the density change between the high and low ammoniates could cause packing problems in a reactor which constrains the salt volume. Subscale tests with solid ammoniates indicated that the heat transfer coefficient in a fixed bed reactor is low (approx. 1 Btu/h-ft exp 2 - exp 0 F). Therefore solid ammoniates are not practical because of the high heat exchanger cost requirement. Forced ammonia recirculation was tested as a means of increasing heat transfer rate in the fixed bed reactor with solid salts, but was not successful. Conversely, the subscale testing with liquid ammoniates produced heat transfer coefficients of 40 to 45 Btu/h-ft exp 2 - exp 0 F. Thus, the residential design was based on a liquid ammoniate/ammonia system using ammonium nitrate as the salt. (ERA citation 07:003859)