Optimization of a lithium bromide-water solar absorption cooling system with evacuated tube collectors using the genetic algorithm

Nowadays absorption chillers are of more interest due to considerable saving in energy consumption and using thermal energy sources. In this paper, a sensitivity analysis is accomplished on a double-effect absorption chiller with 100 t of cooling capacity to study the effect of different parameters on auxiliary energy. The input parameters taken into account in the sensitivity analysis are the volume of storage tank, area of evacuated tube collector, and mass flow rates of water passing through the collector and generator. It is also supposed that the evacuated tube collector is mounted at the monthly optimum angle to get as much solar radiation as possible. Two objective functions are considered for the genetic algorithm namely the auxiliary energy and the net profit obtained from the solar system. An economical analysis is required to calculate the optimum area of collector. The computer code is developed to minimize the auxiliary energy, and maximize the profit. Since the auxiliary energy costs money, it is advantageous to use the same system with minimum auxiliary energy. However, the results show that the optimum mass flow rates of hot water passing through the generator and collector have an important role on reducing the auxiliary energy.