Computerized design and economic evaluation of an aqua-ammonia solar operated absorption system

A computerized simulation and design of solar operated NH₃---H₂O absorption refrigeration cycles is presented. The program receives input data and calculates the building, cooling and heating loads initially. Next the absorption cycle is designed along with the solar collectors and auxiliaries. Various economic parameters are also calculated from which the most favorable system may be selected. Two examples were run: one for the Knesset building in Jerusalem (Israeli parliament) and the other for an American office building. Results indicate the existence of various mininal operating parameters, e.g. collectors' outlet temperature, etc. For the Knesset building some 46 per cent of the annual heating and cooling demand may be provided by the solar system. At the 1979 rate of energy cost increase in Israel the system payback period was estimated at 9 yr with a present value total saving of $42.5 m. Yet higher values were obtained for the American office building at about 81 per cent solar fraction for the compound cooling and heating system.