Advances in standalone and hybrid earth-air heat exchanger (EAHE) systems for buildings: A review

This paper provides an up-to-date survey on recent advances in earth-air heat exchanger (EAHE) systems for buildings, and presents systematic information on the main design parameters and operation condi-tions that affect the overall performance of the technology. This review also aims at providing room for the discussion on how this technology can be used in standalone and/or hybrid schemes, i.e., EAHE sys-tems coupled with other active/passive techniques, such as air conditioners, air source heat pumps, heat recovery units, mechanical ventilation systems and air handling units, evaporative cooling, air humidity control devices, photovoltaic panels, building integrated photovoltaic systems, solar air heaters and heat -ing ducts, solar chimneys, wind towers, building thermal mass and phase change materials. It was con-cluded that further research is required to provide reliable design guidelines for different climates, EAHE configurations, typologies of buildings, sorts of construction, types of soils, and finally, to overcome the main drawbacks of the technology that have restrained its worldwide dissemination. Further studies are also required to numerically and/or experimentally assess the thermal performance, the environmen-tal benefits, and the economic viability of innovative hybrid EAHE systems, since a great research gap per-sists on this matter. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This paper provides an overview of recent advances and design parameters of EAHE systems, discussing potential applications and highlighting the need for further research in this area.