Influence of thermodynamic and thermophysical properties of water-based working fluids for bubble pump operated vapour absorption refrigerator

Miniaturization of the absorption refrigerator requires an air cooled absor ber and condenser and replacement of the customary solution pump by a bubbl e pump. The operating pressures in the bubble pump operated two fluid vapou r absorption refrigerator have to be very low (vacuum) so as to make use of the hydrostatic principle to maintain the required pressure difference bet ween the condenser and evaporator. Hence, only water and alcohol based work ing fluid combinations are found suitable. Thermodynamic properties, such a s specific heat and heat of mixing, and thermophysical properties, such as vapour pressure, density, viscosity, surface tension and solubility, are ne cessary for the overall performance evaluation of such a refrigerator. In t his paper, sixteen water based working combinations have been analyzed and compared with reference to the solution density governing the hydrostatic h eight, viscosity and specific heat affecting the heat and mass transfer and solubility to avoid crystallization. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.