Experimental barium chloride-ammonia cooling cycle study at low generation temperatures

Abstract

Thermally driven cooling systems are becoming increasingly important as an alternative to the conventional mechanical vapour compression cooling systems. Among these technologies, thermochemical cooling offers a large number of chemical reactions in a wide range of operating conditions, which can use low-grade waste heat, as well as solar, biomass or geothermal energy resources. In this work, an intermittent prototype of a single stage thermochemical cooling system, using the reaction: barium chloride and ammonia (BaCl2, 8NH3) was designed, constructed and evaluated. In this work industrial grade reagents were utilized without additive compounds to improve the heat transfer. The pressure-temperature equilibrium was similar to that reported in the literature. The generation temperatures ranged between 54 and 69 °C where up to 6.65 L of liquid ammonia was desorbed. Anhydrous BaCl2 was obtained from dehydration of di-hydrate-BaCl2, which it was carried out into the reactor, in order to evaluate the feasibility of these operations under actual conditions. The thermochemical reaction rate in general depended on the working temperatures and constant pressure; in this work the evaporator temperatures ranged from 2 to 5 °C at absorber temperature at 32 °C.Preliminary results show the feasibility of operating the thermochemical cooling cycle with low temperature sources, with almost constant operating conditions using industrial grade reagents.