Dynamic simulation of an air cooled lithium bromide-water absorption cooling system operating with solar energy

The dynamic performance of a solar absorption refrigeration system using the water-lithium bromide combination is investigated. The study is oriented towards developing a system which would be able to operate at a relatively low evaporator temperature so that it can be used for air conditioning and refrigeration as well. In addition, an attempt is made to meet the heat transfer requirements of the condenser and absorber by air cooling, thus avoiding the use of a cooling tower.Under these considerations, it is shown that the conventional cycle is not likely to operate satisfactorily due to temperature limitations and therefore the cycle is modified appropriately. Initially, a typical steady-state operation is assumed and the system is analyzed in detail both in terms of thermodynamics and heat transfer.For the purpose of dynamic simulation, a computer program is written, in which the results of the heat transfer analysis are introduced as design parameters. Ambient air temperature and solar radiation are the required inputs of the program. System temperatures, concentrations, and energy flows can then be predicted. Typical performance results are discussed and the system is shown to operate satisfactorily at the designed capacity over a significant part of the day.