Numerical Optimization of Double Tube GHE for Ground Source Heat Pump
International Journal of Sustainable and Green Energy
Volume 6, Issue 5, September 2017, Pages: 64-75
Received: Jul. 29, 2017; Accepted: Aug. 7, 2017; Published: Aug. 23, 2017
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Md. Hasan Ali, Graduate School of Science and Engineering, Saga University, Saga, Japan; Department of Energy Science and Engineering, Khulna University of Engineering & Technology, Khulna, Bangladesh
Akio Miyara, Department of Mechanical Engineering, Saga University, Saga, Japan; International Institute for Carbon-Neutral Energy Research, Kyushu University, Fukuoka-shi, Japan
Keishi Kariya, Department of Mechanical Engineering, Saga University, Saga, Japan
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In this paper, a two-dimensional axisymmetric numerical simulation model was developed for optimization of double (coaxial) tube vertical ground heat exchangers (GHEs) in cooling mode. Details of the heat transfer rates and pressure drops for each model are presented and analyzed. The results of the numerical study of optimization of double tube vertical GHEs have been done by considering heat transfer rates and pressure drops. The effect of different inlet and outlet tube diameters, and mass flow rates were numerically investigated. Effect of the different materials on heat transfer and longtime operation also discussed. The double tube vertical GHEs are more effective in laminar flow condition considering balance between heat transfer and pressure drop. The results indicate that since in laminar flow condition, pressure drop is not significantly high, it is possible to reduce the inlet and outlet diameter of double tube GHEs if double tube GHEs operate in laminar flow condition. The heat transfer rate decreased only 17% but diameter of the inlet tube can be reduced from 130 mm to 40 mm with fixed outlet diameter 20 mm. Heat transfer rate can also be enhanced by reducing the outlet tube diameter for a fixed inlet tube diameter. Long time operation suggested the possibility of installation of multiple double tube GHE at 2.0 m apart.
Ground Source Heat Pump, Vertical Ground Heat Exchanger, Double Tube Ground Heat Exchanger, Optimal Design, Numerical Simulation, Heat Exchange Rate, Pressure Drop
To cite this article
Md. Hasan Ali, Akio Miyara, Keishi Kariya, Numerical Optimization of Double Tube GHE for Ground Source Heat Pump, International Journal of Sustainable and Green Energy. Vol. 6, No. 5, 2017, pp. 64-75. doi: 10.11648/j.ijrse.20170605.11
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