Techno‐economic analysis and energy performance of a geothermal earth‐to‐air heat exchanger (EAHE) system in residential buildings: A case study

Abstract

Natural air ventilation in the hot‐dry regions plays a key role to decrease indoor air temperature in hot season, also to improve thermal comfort during the cold season. One of the most common ways to take advantage of natural ventilation is using wind catcher with an underground tunnel. In this method, the tower catches the airflow and directs it to the underground tunnel to decrease the air temperature by transferring heat to the ground, which is cooler in the summer and warmer in the winter. Earth‐to‐air heat exchanger (EAHE) is a modern form of wind catcher with underground tunnel. In this method, air after passing through buried pipes exchanges heat with the ground, and its temperature increases in the winter and decreases during the summer. This study analyzes the energy performance and cost‐effectiveness of earth‐to‐air heat exchanger to be utilized in a residential building in climate condition of the province of Kermanin Iran. In this regard, 9 different configurations of the EAHE are investigated to find the optimized EAHE. The system performance and cost‐effectiveness are studied in 3 different depths including 1, 2, and 3 m with 3 different pipe lengths including 25, 50, and 75 m. The results show that the EAHE is capable of reducing the inlet air temperature by 0.5‐9.9℃ in the summer and increasing it by 0.9‐11.2℃ in the winter. Furthermore, by integrating the EAHEs in a building design, one can reduce the total annual cooling load by 1.25%‐3.97% and for heating by 1.34%‐3.96%. The payback period of the system with a pipe length of 25 m is 16 years, but for the systems with pipe lengths of 50 and 75 m, this period reduces to almost 3 years.

Earth-to-air Heat Exchanger for Cooling Applications in a Hot and Dry Climate: Numerical and Experimental Study

“…Experimental data was used to validate the numerical model in this research. Because of the high Reynolds number of the flow (2.410 4 -1.910 5 ), the turbulent model (k-w SST) was chosen to compute the temperature and velocity of the airflow inside the pipe and the heat transfer in the soil.…”

“…The heat exchanger can be defined as a device to help the process of heat transfer between various materials without direct mixing [4]. The earth-to-air heat exchanger (EAHE) system is considered adequate and economical in the long run [5]. Unfortunately, its use is still limited due to the relatively high initial cost and the difficulty of digging and burying pipes in residential areas.…”

Optimization of microenergy grid including adiabatic compressed air energy storage by considering uncertainty of intermittent parameters

“…Equation (3) measures the state of charge (SOC) of adiabatic CAES with the TES hub. Thermal energy collected by the cooler equipped after compressor at period t during charging can be depicted by (4). Similarly, thermal energy consumed by the heater equipped before the turbine during discharging can be computed by (5).…”

“…Greenhouse gas emissions and the global energy crisis have caused the transformation of conventional energy supplies such as fossil fuel-based power plants. [1][2][3][4] Renewable energy sources (RESs) play a prominent role in addressing environmental issues. [5][6][7] Solar photovoltaic (SPV) and wind turbine (WT) systems have attracted more attention than other RESs.…”

Thermal Performance of EAHE System in Algerian Site: Case Study of Ghardaïa

“…The cooling and the heating of the building are solutions for the energy optimization of the building [1,2]. Reducing the heating and cooling energy consumption of the building via such energy with no CO2 emission as geothermal energy, as an application of the EAHE system [3,4].…”