Amirhossein Khayyaminnejad, Amir Fartaj
Abstract: Rising energy consumption presents a significant global challenge. Current data indicates that heating, ventilation, and air conditioning (HVAC) systems in residential sectors account for 40% of total energy usage, primarily sourced from non-renewable resources. In response to this challenge, scientists are actively exploring ways to decrease reliance on fossil fuels by harnessing renewable energy resources. This research article delves into the thermal performance of a natural ventilation system within a building located in Las Vegas, a city chosen for its hot and arid climate. The study focuses on the implementation of phase change material (PCM) during the peak of summer. The system under investigation comprises a solar chimney, an earth-to-air heat exchanger, and PCM. It is simulated using ANSYS Fluent software, with the RNG k-ε serving as the selected turbulence model. Based on the numerical simulations, n-Henicosane, is chosen specifically to assess its impact on the cooling load when applied to the roof. A key aspect of this research is the exploration of the effect of PCM layer thickness on the thermal performance of the natural cooling system. The natural ventilation system was found to reduce the peak indoor temperature by 15.5 K, resulting in a saving of 28.19 kW of energy during the day. Simulations revealed that the optimal thickness for the PCM layer is 70 mm. Upon integrating the PCM with this optimal thickness into the building, the maximum indoor temperature was further reduced by 2.5 K, reaching a comfortable 298.5 K. Remarkably, this system cut energy consumption by 81% at peak load, saving 33.21 kW over a 24-hour period. In conclusion, the integration of PCM into a building’s rooftop, coupled with a natural ventilation system, emerges as a wise strategy for reducing both indoor temperature and energy demand in hot and arid climates. This research underscores the potential of such sustainable solutions in addressing the pressing issue of increasing energy consumption.
Keywords: PCM, Solar chimney, Natural ventilation, CFD, Renewable energy
Date Published: January 16, 2024 DOI: 10.11159/jffhmt.2024.002
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