A qualitative assessment of integrated active cooling systems: A review with a focus on system flexibility and climate resilience

Space cooling now has the fastest-growing energy end-use in buildings, with an almost tripled energy demand compared to 1990. This paper provides a state-of-the-art review of different integrated active cooling systems for buildings. The cooling systems are classified based on the energy source, with attention to the performance of the systems under multi-criteria assessment. The assessment criteria are described in five main parameters for energy performance, flexibility to energy sources and integration with secondary systems, climate resilience to heatwaves and power outages, as well as building typology, and technology readiness level. The qualitative assessment shows that electricity-driven systems are widely available in the market and have several applications integrated with PV systems. Therefore, they are more resilient to heatwaves. Only chillers are highly integrated with secondary systems among electricity-driven systems. The study also found that only air-cooled and water-cooled chillers can operate in passive cooling mode. It is found that thermal energy-driven systems are more flexible to be driven by different energy sources, in addition to being more resistant to power outages due to their low electrical input. Finally, some recommendations for further research and practice are given based on the study's strengths and limitations.