Earth to Air Heat Exchanger systems: A Comprehensive Review of Design and Performance with Case Applications in Iranian Greenhouses

Document Type : Review Paper

Authors

Faculty member, Renewable Energy Department, Energy and Environment Research Center, Niroo Research Institute (NRI), Tehran, Iran

10.22059/ses.2025.393932.1136

Abstract

The use of Earth-to-Air Heat Exchangers (EAHX) has increasingly been recognized as an effective and innovative approach for providing heating, cooling, and ventilation in various built environments. This study evaluates the performance of these systems through an analysis of existing installations in different countries and assesses their operational outcomes. Key parameters influencing the efficiency of EAHX systems include pipe material, burial depth, pipe length and diameter, surrounding soil type and moisture content, soil thermal conductivity, and airflow rate. Optimal selection and design of these parameters significantly enhance system efficiency and optimize heat exchange between air and the ground. The findings of this research demonstrate that the proper implementation of EAHX systems can lead to substantial energy savings, improved indoor thermal stability, and reduced environmental pollutants. Moreover, the performance of these systems has been examined in several greenhouses across the country, where their positive effects on reducing final production costs and increasing energy efficiency have been confirmed. In some greenhouse applications, a temperature differential of up to 10°C resulted in as much as 70% energy savings, along with improvements in both the quantity and quality of the crops. This has encouraged private sector investment in this field. Given the relatively low initial cost, minimal maintenance requirements, and high efficiency under proper design conditions, EAHX systems can serve as a sustainable and cost-effective solution for greenhouse energy supply in various regions of Iran.

Keywords

Main Subjects

References

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Journal of sustainable Energy Systems
Volume 4, Issue 4
October 2025
Pages 405-425

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