Enhancing cooling performance and economic analysis of a vertical earth air heat exchanger (VEAHE) through geometric shape optimization

Abstract

The cooling and heating sector is responsible for the highest energy consumption in the building sector, comprising approximately 30% of the total. Extensive research has been conducted to address this issue and minimize energy consumption through the implementation of innovative technologies. Among these technologies, the passive earth-air heat exchanger (EAHE) has proven highly effective in reducing energy usage in the cooling and heating sector. This research focused on optimizing U-shaped EAHE systems and examined their functional and thermal-fluidic parameters through numerical analysis. The simulation employed COMSOL Multiphysics software, and the results obtained were in excellent agreement with experimental data. The study investigated a base case, as well as five optimized cases with varying inlet velocities, to evaluate performance. The findings revealed that increasing the working fluid's inlet velocity led to a decrease in the system's thermal efficiency. However, at higher velocities, the economic parameters for energy production showed improvements. Specifically, the system generated a maximum energy output of 9132 W in the fifth case, operating at a velocity of 2 m/s. Additionally, the system achieved an impressive performance coefficient of approximately 5.13 in the same case, with an inlet velocity of 0.46 m/s. Notably, the lowest recorded output temperature of the system was 22°C at the specified inlet velocity.