Design and assessment of earth-air heat exchanger as an intergrated natural cooling system for net zero tropicl buildings.

Abstract

Earth Air Heat Exchangers (EAHE), represent a promising passive technology for addressing cooling and heating needs in buildings by utilizing the earth's stable subsurface temperature. EAHEs have been extensively used for both space heating and cooling over the course of many years, and this topic remains attractive to researchers. Intensive studies have been carried out on this topic concerning the heat and mass transfer characteristics of the EAHE, design and operational parameters, energy saving potential, feasibility study in different climates and buildings and thermal performance of hybrid EAHE systems (Zhao et al., 2024). At depths between 1 to 4 meters below the ground surface, soil temperatures remain relatively constant throughout the year, typically ranging between 10-25°C depending on geographic location and climate zone (El Khachine et al., 2024). This thermal stability provides a natural heat sink for cooling in dry/hot season and a heat source for warming in cold (Peñaloza Peña et al., 2021). The use of EAHE systems for air conditioning in commercial and industrial settings offers several environmental benefits and is capable of operating in both standalone and hybrid modes (Lattieff et al., 2022). The advantages of EAHE systems are particularly relevant for low-income tropical contexts. These systems require no compressors, refrigerants, or fossil fuel combustion, with only low-power fans or blowers needed to circulate air. This translates to minimal operational costs and maintenance requirements compared to conventional air conditioning. EAHE systems can reduce cooling energy demand by 20-30% while simultaneously improving indoor air quality through continuous fresh air ventilation (Li et al., 2023). The technology is compatible with locally available materials and low-skill construction techniques, making it accessible for implementation in resource-constrained settings. Research across various climate zones has demonstrated the effectiveness of EAHE systems. Studies in tropical and hot-arid climates have shown temperature reductions of 10-16°C during peak summer conditions. The design of net zero buildings incorporating natural temperature harnessing technologies like EAHE systems represents a critical intervention point for low-income tropical regions. By dramatically reducing cooling energy demand through passive strategies while providing affordable, renewable-powered thermal regulation, these buildings can break the cycle of energy poverty, improve health and well-being, and contribute to global climate mitigation efforts. This project explores the technical, economic, and social dimensions of integrating EAHE technology within comprehensive net zero building designs tailored to the specific needs and constraints of low-income tropical communities, contributing to the broader global imperative of achieving universal access to sustainable, healthy, and climate-resilient buildings.