Chapter 2.4 - Earth air heat exchangers

Abstract

The aim of this chapter is to present an overview of earth air heat exchangers (EAHEs) and exhibit the main parameters affecting their performance, cost, and environmental impact. These parameters are related to the type and configuration of the EAHE, climate, and shallow geothermal conditions such as pipe diameter, pipe length, depth, soil thermal conductivity, ground temperature, ambient temperature, wind speed, and solar radiation. From the literature, it can be shown that passive EAHEs are usually recommended such that their operating cost is almost zero. The most commonly used passive EAHEs comprise solar chimney or wind tower allowing the natural circulation of air. Additionally, the capital cost of the system can be reduced by integrating the EAHE into the building foundation. Compared with traditional air-conditioning systems, EAHEs have shown significant ecological benefits during operation while their negative impacts are mostly associated with the manufacturing and recycling processes.