Thermal performance of building-integrated horizontal earth-air heat exchanger in a subtropical hot humid climate

The current energy crisis across the globe is a major obstacle to human growth and development. The majority of energy use is accounted for by buildings, which must be controlled and reduced using energy-efficient technologies. Several passive technologies have been shown to be effective in reducing building energy consumption. The earth-air heat exchanger (EAHE) is one such technology capable of saving energy in buildings without relying on habitual mechanical equipment. Though different types of EAHE models have been developed over the last few decades, building-integrated EAHE model development using real-time data is rarely seen for a subtropical climate. This paper thus evaluates the cooling performance of a building-integrated horizontal EAHE system in a warm and humid subtropical climate in Rockhampton, Australia. To measure the cooling performance, a building-integrated horizontal EAHE model is developed in Ansys Fluent. Impacts of relative humidity, air velocity, soil temperature, and air temperature on the building cooling performance have also been investigated. The building-integrated horizontal EAHE system reduced the temperature in a single room building by a maximum of 2.18 °C, saving 415.92 kWh energy (on average 59.91 kWh) during a 3-months summer. This equates to an energy cost savings of AU$190.31, with an average savings of AU$105.10. The energy saved by the present system will make a substantial contribution to building energy management.