Prototype of hybrid refrigeration system using refrigerant R723

A proof of concept 10 kW cooling capacity hybrid refrigeration machine, designed and built at University of Warwick, is described in this paper. The hybrid system uses ammonia mixture R723 (40% Dimethyl ether, 60% Ammonia) which is compatible with conventional refrigeration copper alloy (Cu90Ni10) and environmentally friendly. It combines sorption (thermal) and conventional vapour compression (electrical) technology in two separate refrigerant loops. Shell and tubes adsorption generators with activated carbon - R723 pair are used as thermal compressor while a semi hermetic reciprocating compressor is used in the conventional vapour compression loop. The hybrid machine is designed as water chiller with an evaporation temperature of 5 °C and condensing temperature of 40 °C. The preliminary experimental tests are mainly designed to check the system operational functionality. Those preliminary results show a maximum cooling production of 6 kW with 2/3 from mechanical compression and 1/3 from thermal compression (adsorption cycle). Further additional work is yet to be carried in order to establish full and detailed performance of prototype under development.