Experimental investigation of earth-air ventilation system in low-energy buildings

Low-energy ventilation plays a critical role in achieving low/net zero energy buildings. Buildings require ventilation to provide healthy indoor air quality and to remove pollutants, moisture, and Odors. However, traditional ventilation systems consume significant amounts of energy to condition the incoming air to the desired temperature and humidity levels. Low-energy ventilation systems, on the other hand, use less energy to provide fresh air and can help to reduce the overall energy consumption of the building. One type of low-energy ventilation system is an earth-air heat exchanger (EAHE), which uses buried pipes to precondition the incoming air by exchanging heat with the surrounding soil. This approach can significantly reduce the energy required to heat or cool the ventilation air, as the soil maintains a relatively stable temperature throughout the year. This paper presents an experimental investigation of an earth-air heat exchanger (EAHE) for low-energy ventilation in low-energy buildings. The EAHE system consists of a buried horizontal pipe that preconditions the incoming ventilation air by exchanging heat with the surrounding soil. The study aims to evaluate the effectiveness of the EAHE system in terms of its thermal performance and energy savings potential. The experimental setup consists of a building integrated EAHE system, which is connected to a building’s mechanical ventilation and heat recovery system. The system is designed to simulate typical residential conditions and is subjected to varying outdoor temperatures and air-flow rates. The performance of the EAHE system is evaluated by measuring the air and soil temperature of the incoming and outgoing air streams, as well as the energy consumption of the ventilation unit. The experimental results indicate that the EAHE system is capable of significantly reducing the temperature and humidity of the incoming air stream during hot and humid conditions, and increasing it during cold and dry conditions. The system is found to be effective in reducing peak inlet air temperature by up to 10 K and increasing winter inlet air temperature by up 7K, reducing the energy consumption of the ventilation unit by up to 30% compared to conventional ventilation systems.