Combined flash-vaporisation and solar evacuated tube heat-driven absorption air conditioning system for the tropic

Abstract

A theoretical study based on the thermodynamic consideration has been conducted for a combined flash-vaporisation and solar evacuated tube, heat-driven air conditioning system for cooling of buildings under the tropic weather conditions. The initial analysis has shown that the performance of a basic (lithium bromide–water) LiBr-H2O absorption cooling system can be enhanced with an evacuated-tube collector coupled with the addition of a ‘flash vaporisation’ unit. The preliminary computational results based on the thermodynamic consideration demonstrated the system efficiency increment patterns prevailed in the system associated with the evacuated tube-generator input temperature, subject to the local meteorological and the solar thermal energy characteristics. Subsequently, a parametric study was conducted to explore the influence of the principle operating parameters on the performance of the basic single stage, cooling cycle of the absorption air conditioning system. The parametric findings and the monographs thus developed are beneficial for both designer and user’s guide, especially for tropical solar-absorption application consideration. The analytical results revealed that coupled with the evacuated tube, the flash vaporisation could enhance the overall system performance. The recommended operating range, based on local cooling requirements are: generator pressure, 0.08-0.12 bar with generator, condenser, absorber and evaporator temperature ranges of 85 – 100 C°; 37 - 50°C, 29 - 35°C and 5 - 14°C respectively.