What is it about?

Cooling buildings normally requires a lot of electricity, especially in hot climates. This study looks at cleaner alternatives that use solar energy instead of electricity. We compared two types of solar-powered cooling technologies—adsorption and absorption systems—both supported by a latent heat storage tank (LHST) that stores solar heat during the day and releases it when needed. To understand which designs work best, we simulated different combinations of solar collectors (parabolic trough and evacuated tubes), cooling technologies, and two phase-change materials (PCMs): erythritol and magnesium chloride hexahydrate (MgCl₂·6H₂O). These materials melt and solidify at specific temperatures, allowing them to store large amounts of heat in compact volumes. The simulations showed how each system performed throughout the day, how much solar energy they captured, and how effectively the heat storage supported the cooling demand. Overall, absorption cooling achieved the highest efficiency, and parabolic trough collectors captured more heat than evacuated tubes. Erythritol stored more energy but at a higher cost, while MgCl₂·6H₂O offered better thermal response and lower cost.

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Why is it important?

Air conditioning is responsible for a significant share of global electricity use. Replacing traditional systems with solar-driven cooling can dramatically reduce energy demand and greenhouse gas emissions. This work is important because it provides one of the most detailed comparisons of adsorption and absorption systems using advanced PCMs under realistic dynamic conditions. The study identifies which combinations of collector type, storage material, and cooling cycle achieve the highest solar fraction—meaning how much of the cooling demand can be met solely by the sun. The results show that, with the right configuration, solar energy can fully power cooling needs without relying on fossil-fuel-based electricity. These insights help guide engineers, researchers, and policymakers in designing more sustainable and efficient building cooling systems.

Perspectives

This research advances the understanding of how solar cooling technologies interact with latent heat storage materials under real operating conditions. Future work could explore long-term durability of PCMs, economic optimization, hybrid configurations using both adsorption and absorption, and integration with smart control systems to further reduce auxiliary heating. The study strengthens the path toward scalable, cost-effective, and environmentally friendly cooling for buildings.

Professor Rosenberg J Romero
Universidad Autonoma del Estado de Morelos

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This page is a summary of: Comparative Simulation of Solar Adsorption and Absorption Cooling Systems with Latent Heat Storage with Erythritol and MgCl2·6H2O, Processes, August 2025, MDPI AG,
DOI: 10.3390/pr13082655.
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