ABSTRACT
Earth air tunnel heat exchanger (EATHE) is a promising passive technique to provide thermal comfort condition in buildings. EATHE system uses undisturbed temperature of the ground for heating/cooling of air. Despite the several advantages, this technique has not become much popular owing to its high capital cost (mainly pipe cost and trench excavation cost) and large land area requirements. The primary objective of this study is to present a comprehensive review of different EATHE pipe layouts, pipe properties and positioning of the pipe with their advantages and limitations. It is observed that the ring pipe layout is the most cost-effective pipe-layout for small size EATHE system because it saves excavation cost by using a trench of the existing foundation of the building. However, Grid pipe-layout is an ideal layout for a large size EATHE system. Multi-layer pipe layouts should be used to reduce the land area requirement significantly. Moreover, EATHE system can be installed beneath the building (under building foot-print) to eliminate extra land area requirement for the installation of EATHE system. This review article shows that the Initial capital cost and land area requirement for the EATHE system can be substantially reduced by using appropriate pipe layout. It can be concluded that if EATHE system is installed with proper design strategies, it will be a clean and cost-effective method for building heating/cooling with significant power savings.
Research highlights
Earth air tunnel heat exchanger (EATHE) system is one of the promising passive techniques for building heating and cooling application.
Due to high capital investments and large area requirement, EATHE did not gain much popularity.
Land area requirement for EATHE pipe installation can be substantially reduced by using optimum pipe layout.
Multi-layer pipe system helps in reducing the land area requirement for EATHE installation.
The EATHE pipe should be buried beneath the building to reduce the excavation cost and land area requirement.
Abbreviations
AC | = | Air Conditioning System |
CFD | = | Computational Fluid Dynamics |
EAHE | = | Earth-Air Heat Exchanger |
EATHE | = | Earth Air Tunnel Heat Exchanger |
GAHE | = | Ground-Air Heat Exchanger |
GHE | = | Ground Heat Exchanger |
GSHP | = | Ground Source Heat Pump |
PCM | = | Phase Change Material |
PVC | = | Poly Vinyl Chloride |
TIZ | = | Thermal Influence Zones |
Acknowledgments
The corresponding author is grateful to the MHRD, Government of India, for providing the research fellowship for pursuing PhD at MNIT Jaipur, India