Design and Analysis of Energy-Efficient Air-Cooling Systems for Domestic Applications: A Review

The rapid growth of residential cooling demand has increased electricity consumption, peak power requirements, operating costs, and environmental impacts associated with conventional air-conditioning systems. This review examines the design and analysis of energy-efficient air-cooling systems suitable for domestic applications, with particular emphasis on direct evaporative cooling, indirect evaporative cooling, hybrid cooling, variable-speed vapor-compression systems, passive cooling strategies, and intelligent control. The thermodynamic principles, major design parameters, performance indicators, advantages, limitations, and applicability of these technologies are critically discussed. Evaporative cooling can provide substantial energy savings because it relies primarily on the latent heat of water evaporation rather than mechanically driven vapor-compression refrigeration. However, direct evaporative cooling increases indoor humidity and is therefore less suitable for hot-humid climates. Indirect evaporative cooling overcomes part of this limitation by cooling the primary air without direct moisture addition. Hybrid systems combining evaporative and mechanical cooling can provide an effective compromise between energy efficiency and humidity control. In addition, variable-speed compressors and fans, improved building envelopes, demand-controlled ventilation, thermal storage, and smart control can further reduce domestic cooling energy consumption. The review identifies climate-responsive design, water consumption, indoor air quality, system cost, maintenance, and control optimization as important considerations. A conceptual energy-efficient domestic cooling system is proposed in which passive heat-load reduction is combined with variable-speed mechanical cooling and an indirect/direct evaporative precooling stage. The review concludes that no single cooling technology is universally optimal; instead, system selection should be based on climate, indoor humidity, cooling load, water availability, occupant requirements, and life-cycle energy performance.