Parametric study on thermal performance of horizontal earth pipe cooling system in summer

Highlights: • Horizontal earth pipe cooling (HEPC) performance was investigated by a parametric study. • A thermal model was developed using FLUENT for the parametric study. • Air velocity, pipe length and pipe diameter showed noticeable impact on HEPC performance. • Pipe length greatly influenced the HEPC performance compared to other parameters. - Abstract: Rational use of energy and its associated greenhouse gas emissions has become a key issue for a sustainable environment and economy. A substantial amount of energy is consumed by today's buildings which are accountable for about 40% of the global energy consumption. There are on-going researches in order to overcome these and find new techniques through energy efficient measures. Passive air cooling of earth pipe cooling technique is one of those which can save energy in buildings with no greenhouse gas emissions. The performance of the earth pipe cooling system is mainly affected by the parameters, namely air velocity, pipe length, pipe diameter, pipe material, and pipe depth. This paper investigates the impact of these parameters on thermal performance of the horizontal earth pipe cooling system in a hot humid subtropical climate at Rockhampton, Australia. For the parametric investigation, a thermal model was developed for the horizontal earth pipe cooling system using the simulation program, FLUENT 15.0. Results showed a significant effect for air velocity, pipe length, and pipe diameter on the earth pipe cooling performance, where the pipe length dominated the other parameters.