Loading...

A numerical model for transient simulation of borehole heat exchangers

Biglarian, H ; Sharif University of Technology | 2017

1002 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.renene.2016.12.010
  3. Publisher: Elsevier Ltd , 2017
  4. Abstract:
  5. A numerical model is developed to simulate the borehole heat exchanger both in the short and long time. In this regard, the computational domain is divided into the inside and outside borehole regions. A two-dimensional finite volume method is implemented in a cylindrical coordinate system for modeling of the outside borehole. Also, a thermal resistance-capacity model is presented for the borehole cross section. This model is extended to take into account the fluid transport through the U-tube and the temperature variation of the borehole components with depth. The governing equations of the two regions are solved iteratively in each time step. The proposed model is verified with the previously reported numerical, experimental and analytical results. Furthermore, the ability of the model in predicting the short-time response is evaluated in comparison with a three-dimensional computational fluid dynamics (CFD) model with a fine grid. The results show that the proposed model has a good performance in the prediction of the thermal response of the borehole in a wide time interval from 1 min to over 10 years. Moreover, the effects of time step size and number of capacity nodes on the results are investigated. © 2016 Elsevier Ltd
  6. Keywords:
  7. Borehole ; Ground heat exchanger ; Ground-source heat pump ; Short-time response ; Boreholes ; Finite volume method ; Geothermal heat pumps ; Heat exchangers ; Heat pump systems ; Iterative methods ; Transport properties ; Borehole heat exchangers ; Computational domains ; Cylindrical coordinate systems ; Ground heat exchangers ; Long-time response ; Temperature variation ; Three dimensional computational fluid dynamics ; Numerical models ; Computational fluid dynamics ; Equipment ; Fluid flow ; Heat flux ; Heat production ; Numerical model ; Prediction ; Thermal regime
  8. Source: Renewable Energy ; Volume 104 , 2017 , Pages 224-237 ; 09601481 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S096014811631059X