Performance Comparison of Three Different Horizontal Ground Heat Exchanger Patterns Using Computational Simulations

Rapid technological improvements in computational power have leaded researchers to use numerical simulations as
alternative tools for parametric assessments of engineered systems, since computational simulations require less labor
cost and time than experimental analyses. In this study it was intended to use the advantage of computational
simulations in the assessment of the effect of different geometrical patterns on in- and out- temperatures of horizontal
ground heat exchangers. Out of three different patterns tested in this study, first two were chosen according to our
previous two-dimensional study in which five different patterns were numerically tested for pressure loss. In addition
to these two patterns a genuinely designed new pattern was also tested for performance comparison. Heat exchangers
were placed in 0.95 meters below the soil surface. Turkiye’s average soil temperatures measured by National
Meteorology Department in 2019 were used to establish soil surface temperature in the representative soil domain
which had the width, depth and height of 6.64×5.64×1.00 (in meters), respectively. The results were calculated for 72
hours of running in month of October. For the ease of numerical calculations water was chosen to be working fluid.
The results showed that the water temperature difference between in- and out- of all patterns were very close to each
other. ΔT was found to be 3.19°C, 3.19°C, 3.18°C for the patterns 1, 2, 3, respectively. Since the results were very
close to each other, it is believed that further tests are needed to uncover whether the slight differences were either
because of numerical approximations or parametric input data.