Solution procedure and performance evaluation for a water–LiBr absorption refrigeration machine

• Analysis of a water–LiBr absorption machine, including detailed solution procedure.
• Performance assessed using first and second law considerations, as well as flow ratio.
• Effects of heat source and refrigerated environment temperatures on the performance.
• Effects of the difference between condenser and absorber temperatures.
• Effects of internal heat exchanger efficiency on overall cooling machine performance.

The water–lithium bromide absorption cooling machine was investigated theoretically in this paper. A detailed solution procedure was proposed and validated. A parametric study was conducted over the entire admissible ranges of the desorber, condenser, absorber and evaporator temperatures. The performance of the machine was evaluated based on the circulation ratio which is a measure of the system size and cost, the first law coefficient of performance and the second law exergy efficiency. The circulation ratio and the coefficient of performance were seen to improve as the temperature of the heat source increased, while the second law performance deteriorated. The same qualitative responses were obtained when the temperature of the refrigerated environment was increased. On the other hand, simultaneously raising the condenser and absorber temperatures was seen to result in a severe deterioration of both the circulation ratio and first law coefficient of performance, while the second law performance indicator improved significantly. The influence of the difference between the condenser and absorber exit temperatures, as well as that of the internal recovery heat exchanger on the different performance indicators was also calculated and discussed.