Solar-Assisted Absorption Cooling System Performance in Desert Climates: A Case Study

Abstract: The paper is a detailed performance report on a solar-assisted single-effect lithium bromide-water (LiBr–H₂O) absorption cooling system installed and commissioned in Riyadh, Saudi Arabia -a typical hot-arid desert climate. The system combines evacuated tube solar collectors (ETCs) with a 35 kW absorption chiller, a thermal storage tank, and a backup gas heater. Twelve months of experimental data were taken to obtain the complete range of seasonal performance. Absorption chiller coefficient of performance (COP) varied between 0.61 in winter to 0.78 in peak-summer conditions, and the solar fraction was greater than 82% in June-August. On a sunny summer day, the entire system solar COP was 0.52. A techno economic analysis indicates a payback period of about 8.4 years as compared to a standard vapor-compression base, with an average CO₂ reduction per year of 18.7 tonnes. Parametric sensitivity tests test the effect of hot-water supply temperature (75–95 oC), cooling water temperature (28-36 oC) and chilled-water set point (6-12 oC) on chiller performance. The results of the simulation using TRNSYS 18 report a good match with measured values (RMSE ≤ 4.3%). These results substantiate the idea that solar absorption cooling can be thermally viable and cost-competitive in desert conditions with optimal system design and operational strategies.