Comparison of two similar solar driven absorption chillers for different values of solar radiations

Within the Programme Vigoni for cooperation between Italian and German universities, a research work has been carried out between the University of Perugia, Industrial Engineering Department and the Technische Universität Berlin, Institut für Energietechnik on the theoretical analysis and the operational experience of solar cooling plants. The laboratories of the two universities house two similar solar driven absorption plants, with evacuated tubes solar collectors and Water-Lithium Bromide thermosyphon absorption refrigerators of the same manufacturer, but of different cooling capacity. In both plants measurement facilities allow to record in real time all the main operating parameters of internal and external circuits (temperatures, pressures and flow rates). It is known that the main problem for such solar chiller system is to have the highest feeding temperature when the refrigerating load request is greater since many parameters influence their correlation. Therefore, the aim of research has been focusing on the study of feeding temperature variations versus solar radiation and some system parameters, for both absorption chiller, conditions to find the optimal one.