Mitsuharu Matsuo

Formation Conditions of Clathrates Between HFC Alternative Refrigerants and Water

There are two promising candidates as alternative refrigerants for air-conditioners and heat pumps. The first is R407C, which is composed of HFC-32 (23 mass%), HFC-125 (25 mass%), and HFC-134a (52 mass%). The second is R410A, which is composed of HFC-32 (50 mass%) and HFC-125 (50 mass%). In this study, formation conditions of clathrate compounds between water and HFC alternative refrigerants such as HFC-32, HFC-125, HFC-134a, and their mixtures, R407C and R410A, were investigated. Phase diagrams of clathrates of these HFC alternative refrigerants and their mixtures were determined. From the phase diagrams, the critical decomposition temperature and the critical decomposition pressure were determined. The relationship between the critical decomposition points for the clathrates of HFC-32, HFC-125, HFC-134a, R410A, and R407C were studied. It is found that R407C and R410A form clathrate compounds with water under the evaporating temperature condition in the refrigeration cycle of air-conditioners and heat pumps.

Phase equilibria of some alternative refrigerants hydrates and their mixtures using for cool storage materials

Electric power demand for residential air-conditioning has been increasing in Japan. Development of cool storage systems which shifts this demand to off-peak period and contributes to the load leveling of power generation is necessary. The hydrate cool storage system is the suitable cool storage system because its cool storage density is large and chiller efficiency is high. In this study, alternative refrigerants HFC-32(CH/sub 2/F/sub 2/), HFC-125(C/sub 3/CHF/sub 2/) gas hydrate and their mixture were selected for cool storage materials. The phase equilibria of these alternative refrigerants gas hydrates and its mixtures were obtained. From these phase equilibria, the critical decomposition temperature, the critical decomposition pressure and the heat of formation of these gas hydrates were determined.