Optimization study of a single-effect water–lithium bromide absorption refrigeration system powered by flat-plate collector in hot regions

• A comprehensive analysis for optimizing solar absorption system in hot region.
• The most important parameter to be controlled is hot source temperature.
• Ensuring appropriate choice of parameters, COP of absorption unit exceeds 0.8.
• Results show that solar cooling systems are promising in hot regions.
• The research aims to play a vital role to promote the use of renewable energy.

This investigation has been carried out to present a comprehensive analysis for optimizing the operation of solar absorption system in hot regions. To optimize performance of the system, the hot source temperature should be controlled in function of incident solar radiation, chilled and cooling water temperatures. With an appropriate control, these external conditions can be monitored to detect and implement the actual optimization conditions. Adopting typical values encountered in hot regions, the overall system performance takes its optimal value at temperatures between 75 and 80 °C. It was found that in designing or selecting solar collector, selective coating type is necessary to produce hot water with potential around 80–90 °C needed to optimize operation of absorption unit. By ensuring an appropriate choice of components temperatures, COP of absorption unit can exceed the value 0.8. Cooling water temperature above 40 °C reduces significantly the performance of the unit which requires, under conditions of extremely high external temperatures, dimensioning and selection of condensers and absorbers that guarantee values less than this limit.