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Designing Solar-Driven Chillers for Direct Air Cooling: Technologies, Integration, and Performance Analysis

The escalating global demand for cooling, driven by population growth and rising living standards, places immense strain on conventional electricity grids and contributes significantly to greenhouse gas emissions. Solar-driven chillers offer a compelling sustainable alternative by directly converting solar thermal energy into cool air, aligning cooling demand with solar availability. This report provides a comprehensive analysis of the core technologies—solar absorption and desiccant cooling systems—alongside critical design considerations for solar thermal collectors, thermal energy storage, and advanced control strategies. While absorption chillers (COP typically 0.65-0.75) use high-temperature heat (80-120°C) with refrigerant-absorbent pairs like LiBr-water, desiccant systems (COP 0.275-1.89) operate at lower temperatures (50-80°C) and excel at humidity control. The selection of solar collectors (flat plate, evacuated tube, concentrating, or PVT) is directly linked to the required operating temperature of the chiller and the local climate, significantly impacting system efficiency and cost. Thermal energy storage, encompassing sensible, latent (Phase Change Materials), and thermochemical methods, is essential to overcome solar intermittency, enable continuous operation, and optimize system performance through load shifting.