Designing and evaluating a new earth-to-air heat exchanger system in hot summer and cold winter areas

Abstract

Energy demand for space cooling and heating in buildings is a primary contributor to the total building energy consumption. Its rapid increase calls for an urgent need to utilize renewable energy sources and associated energy-efficient technology in the building sector. Among different renewables, geothermal energy has been widely adopted due to its easy access and low impact on the environment. In this study, a new earth-to-air heat exchanger (EAHE) system with vertically buried tubes was proposed. Compared to the conventional EAHE systems, its advantages mainly include high geothermal energy utilization efficiency and ease of condensate water discharge. To evaluate the thermal performance and cooling capacity of this system, an experimental set-up was established and a series of tests were conducted in Hunan, China. The results show that the outlet air temperature of this system ranged from 22.4℃ to 24.2℃ as the air flow velocity set at 1.0 m/s, enabling it to be used as an energy efficient technology for summer cooling of buildings. Meanwhile, both inlet air temperature and air flow velocities have an important influence on the system's cooling capacity.