Proceedings of the International Conference on Advances in Energy Research and Applications (ICAERA'20) Virtual Conference – September 9-10, 2020 Paper No. 113 DOI: 10.11159/icaera20.113 ICAERA 113-1 Transient 3D Numerical Simulation of Horizontal Earth Water Heat Exchanger (EWHE) Hanin Atwany 1 , Mohammad O. Hamdan *,1 , Bassam A. Abu-Nabah 1 , Mousa Attom 2 , Abdul Hai Alami 3 1 Department of Mechanical Engineering, American University of Sharjah Sharjah, United Arab Emirates g00077160@aus.edu; mhamdan@aus.edu; babunabah@aus.edu 2 Department of Civil Engineering, American University of Sharjah Sharjah, United Arab Emirates mattom@aus.edu 1 Department of Sustainable Renewable Energy Engineering, University of Sharjah Sharjah, United Arab Emirates aalalami@sharjah.ac.ae Abstract - In this paper, the thermal performance of a horizontal earth tube heat exchanger is investigated. A three-dimensional model has been created using ANSYS Fluent to study the performance of a ground horizontal earth water heat exchanger (EWHE). The effect of inlet water temperature, water velocity, soil thermal conductivity and ground surface temperature on the rate of heat transfer has been analyzed. The results have indicated a direct relation between soil thermal conductivity and the rate of heat transfer. On the other hand, an inverse relation has been observed between ground surface temperature and the rate of heat exchanged. The transient model shows that interim operation of EWHE is needed since ground becomes saturated with thermal energy. Keywords: Earth water heat exchanger; shallow ground thermal energy; ground heat capacity; Soil thermal conductivity. 1. Introduction The demand for energy is growing rapidly due to population growth and human growing needs. One of these needs is providing air-conditioning to assure human comfort. In the GCC region, the cooling needs consume around 70% of the overall energy produced during summer peak time. To reduce such high demands of energy, engineers are trying to use passive geothermal energy as way to reduce such a high demand. Nevertheless, very few studies are available on the use of geothermal in the GCC region which make it difficult for a field engineer to decide on implementing such an approach. One approach towards the application of geothermal energy, utilizing shallow ground thermal energy, is the use of earth water heat exchanger (EWHE) which uses earth’s massive thermal capacitance provides [1, 2]. Geothermal cooling has been investigated in various regions as a method of decreasing the cooling load [3]. As shown in the literature, EWHE can reduce the energy peak demand and cut fossil fuel consumption, which reduces carbon emissions [4]. The performance of EWHE depends on soil thermal properties and EWHE design parameters. As showed in the literature [5, 6], EWHE thermal conductivity can play a major role in sizing EWHE. The thermal conductivity of soil depends on many parameters including water content, soil compaction and chemical composition. The effect of water content and soil compaction have been investigated by Atwany et al. [7] who showed that water content have more significant effect on varying thermal conductivity than compaction level. The effect of soil on the earth heat exchanger depends on the working fluid used in the heat exchanger [8]. T’Joen et al [8] has showed that the soil thermal conductivity has a strong impact on EWHE in comparison to earth air heat exchanger (EAHE). Since heat transfer in EWHE is considered a transient and non-uniform process, one needs to implement numerical simulations to obtain proper prediction of EWHE operation performance. Congedo and his team [9] have used numerical simulation to study the performance of horizontal ground heat exchangers under different configurations. Congedo et al. [9] has found that ground thermal conductivity had the greatest impact on the rate of heat transfer followed by the fluid velocity. The effect of EWHE configuration has been numerically examined by Bezyan et al. [10] who has reported that the best performing configuration is the spiral-shaped in serial connection.