Advances in indirect evaporative cooling: principles, integrated cycles, economic insights, and environmental implications

Indirect evaporative cooler (IEC) utilizing dew point cooling has strong potential as an alternative to the classical vapor compression cycles. This review merges recent advancements in IEC technologies, focusing on design parameters, operating conditions, and system integrations that enhance cooling effectiveness and energy efficiency. Different IEC configurations are discussed, including classical, regenerative dew point, and Maisotsenko cycle (M−cycle) systems. Particular emphasis is placed on hybrid solutions where IEC is integrated with humidification–dehumidification desalination, thermal energy storage, liquid/solid desiccant wheel (DW), mechanical vapor compression, and inverted Brayton cycles. Performance improvements are linked to design variables such as airflow conditions, channel geometry, evaporative materials, and system configuration. Notable enhancements are achieved with counter-flow arrangements, high inlet air temperature, low humidity, reduced channel height, optimized velocity, longer channels, and fabric-based triangular channels. Comparative results show that IEC-Brayton systems can achieve energy efficiency up to 44.43%, while IEC-DW systems demonstrate superior wet effectiveness and coefficient of performance. Beyond performance, the paper highlights economic and environmental benefits, underscoring reduced energy consumption and emissions. This comprehensive review provides valuable insights into the optimization, integration, and future applications of IEC technologies, positioning them as sustainable and adaptable cooling solutions for diverse climates and sectors.