Comprehensive Review of Analytical and Numerical Approaches in Earth-to-Air Heat Exchangers and Exergoeconomic Evaluations

In recent decades, Earth-to-Air Heat Exchangers (EAHEs), also known as underground air ducts, have garnered significant attention for their ability to provide energy-efficient cooling and heating solutions while maintaining a minimal environmental footprint. These systems leverage the relatively stable underground temperature to regulate indoor climates, reducing reliance on conventional heating, ventilation, and air conditioning (HVAC) systems. This review systematically categorizes and synthesizes research on EAHEs into three primary areas: analytical, numerical, and exergoeconomic studies. Analytical approaches focus on developing theoretical models to predict thermal performance, while numerical simulations provide insights into system optimization and real-world applications. Exergoeconomic analyses, integrating thermodynamic efficiency with economic considerations, offer valuable perspectives on cost-effectiveness and long-term viability. By consolidating existing contributions across these domains, this study serves as a comprehensive reference for researchers, engineers, and policymakers seeking to enhance the design, implementation, and performance of EAHE systems. The findings emphasize the pivotal role of EAHEs in reducing energy consumption, lowering greenhouse gas emissions, and improving economic sustainability. Additionally, this review identifies key challenges, including soil thermal conductivity variations, moisture effects, and system integration with renewable energy sources, which require further investigation. By addressing these challenges, EAHEs can be further optimized to serve as a cornerstone in sustainable energy management, contributing to global efforts toward energy-efficient building solutions and climate change mitigation.