The Earth Air Heat Exchanger EAHE is a device

The Earth-Air Heat Exchanger (EAHE) is a device that can be defined as an underground heat exchanger, composed by one or more buried ducts, that can to harness (by capturing and/or dissipating) the thermal PF-8380 of the superficial layers of soil, through the insufflated air flow inside it. Commonly, EAHEs are used on the improvement of the thermal condition of built environments, promoting a meaningful reduction in the electrical energy consumption of traditionally used air conditioning equipment. These devices have a simple and efficient main operational principle: the external air is propelled to pass within buried ducts, exchanging heat with the surrounding soil, and coming out of the ducts with a milder temperature which allows its use to enhance the thermal condition inside the buildings (Fig. 1). As explained in Ref. [26], the EAHEs can operate because the solar radiation that reaches the soil surface is absorbed and stored as thermal energy. Due to its immense mass and insulating properties, relative to heat flux, the superficial layers of soil present lower temperatures than the external air during warm periods (Fig. 1a), likewise, during cold seasons the subsoil temperature is warmer than the external air (Fig. 1b). However, during periods in which the external air presents intermediate temperature magnitudes, the use of an EAHE is not so effective (Fig. 1c).