Thermal Performance, Efficiency and Applications of Solar-driven Cooling Systems in Hot Climate Areas: A Narrative Review

Abstract

The Global Cooling Watch predicts that the cooling demand will triple by the year 2050. With heatwaves being the deadliest climate hazard, the burden of cooling is increasing, especially in the densely populated areas of equatorial cities. Interestingly, the sun, which promotes the cooling demand, is itself the solution to excessive heat. This thermodynamic alignment is unique because there is no other thermodynamic system that utilizes solar energy so accurately to satisfy demand. In spite of all these benefits, solar cooling systems represent fewer than 1,500 large-scale installations across the world. To tackle this, we located relevant literature by searching in Scopus, Web of Science, and Google Scholar, and further articles were located using citation chains. Our target markets are hot climatic areas such as the Middle East and North Africa, South and Southeast Asia, Sub-Saharan Africa, and some areas in Mediterranean Europe. We used a single solar-to-cooling coefficient of performance (COPsol) to enable us to compare them with other technologies. In the studies considered, we discover that across all technologies, measured performance is consistently lower than manufacturer-rated values, with reported gaps ranging from approximately 6% to 21% under peak summer conditions. Ambient temperature, heat rejection limits and system operation play a powerful role on performance as opposed to design specifications. These results emphasize the constraints of using rated values of performance on systems design in hot climates. Future implementation must focus on data field-tested and enhance heat rejection plans as well as standard performance measures to ensure steady system sizing and functionality.