Advancements in vapor compression air conditioning systems for high ambient temperature applications: A comprehensive review

Vapor compression air conditioning (VCAC) system is widely recognized for its simple design, high energy efficiency, and reduced environmental impact, making it increasingly popular for various applications. Even though challenges persist in its practical use, particularly for cooling indoor spaces in extremely hot climates, innovations and advancements in this technology are crucial and necessary for a sustainable future in terms of environmental impact and energy efficiency. Over the past two decades, numerous research groups have focused on enhancing VCAC systems to improve their performance and reliability for cooling applications at high ambient temperatures (HATs). This paper reviews recent advancements in VCAC systems particularly in hot regions, categorizing advanced systems into two types: single-stage and modified compression systems. The review on single-stage systems is classified based on components, working fluids, and alternatives, while the review on novel compression systems is categorized based on the count of compressors and distinct loops into mechanical subcooling, cascade compression, multi-stage compression, and injected compression systems. In addition, the summarized work analyzes the cooling performances and attributes of various classifications of compression systems, and components employing diverse working fluids and intermediate configurations. Moreover, this study discusses various challenges that limit the widespread application of these advanced systems in hot regions. Finally, this paper suggests solutions that can guide future research and further advancements in the field.