A study on heat absorbing and vapor generating characteristics of H2O/LiBr mixture in an evacuated tube

It is well known that application of solar powered absorption refrigeration (SPAR) systems will save energy, especially for air conditioning during the summer. This paper presents a SPAR system where evacuated tubes act as both solar collector and solution generator simultaneously while aqueous lithium bromide (H2O/LiBr) is used as the working fluid. In order to investigate the heat absorbing and vapor generating characteristics of lithium bromide solution in the evacuated tube, a test system was built and tested outdoors in Guangzhou in October 2015. The test results showed that lithium bromide solution in an evacuated tube can be heated up rapidly and generate vapor continuously. The vaporization rate, the solution concentration, the equivalent refrigerating capacity, the total energy absorbed by the solution, the thermal collecting efficiency and the solar coefficient of performance in theory were analyzed according to the test data. The work provides a reference for the design and simulation of SPAR systems where evacuated tubes are used as both solar collector and lithium bromide solution generator.