A review on energy piles design, sizing and modelling

Boreholes and energy piles coupled with ground source heat pump plants utilize renewable geothermal energy for buildings heating and cooling purposes and need proper design and sizing in order to end up with high plant efficiency. This paper conducted a review of available scientific literature, design standards and guidelines on energy piles performance within the framework of the IEA-ECES Annex 31. Main aspects covered were typical plant solutions, configurations of energy piles and their thermal response test performance, available analytical and numerical models with their main features and application in commercial software and design manuals. Four typical fundamental schemes of geothermal plant with energy piles were found, both suitable for cold and hot climate applications. Properly sized heat pump systems with energy piles were characterized with high overall system SCOP values higher than 4.5, while some case studies reported two times smaller SCOP values that illustrates the effect of proper design and sizing of such systems. The lack of specific heat extraction values which could be determined based on the climate and energy pile application show the need to develop general procedures for early stage energy pile sizing that would allow quick estimates of the heat extraction/rejection potential and system performance with reasonable accuracy for conceptual design. Most of available software is borehole oriented and will fit for energy piles sizing if software supports variable ground surface temperature boundary conditions, which, however is not implemented in most of software packages. Expected software features to be implemented are water advection and multiregional surface boundary heat transfer.

[1]  Simon J. Rees,et al.  A transient two-dimensional finite volume model for the simulation of vertical U-tube ground heat exchangers , 1999 .

[2]  Hongxing Yang,et al.  The analysis on solid cylindrical heat source model of foundation pile ground heat exchangers with groundwater flow , 2013 .

[3]  Prasenjit Basu,et al.  A practical heat transfer model for geothermal piles , 2013 .

[4]  Michele De Carli,et al.  Thermal performance of two types of energy foundation pile: Helical pipe and triple U-tube , 2013 .

[5]  L. M. López-González,et al.  Finite cylinder-source model for energy pile heat exchangers: Effects of thermal storage and vertical temperature variations , 2014 .

[6]  Altug Sisman,et al.  Experimental and computational investigation of multi U-tube boreholes , 2015 .

[7]  Stephen P. Kavanaugh,et al.  Ground Source Heat Pumps : Design of Geothermal Systems for Commercial and Institutional Buildings , 1997 .

[8]  Jeffrey D. Spitler,et al.  A short time step response factor model for vertical ground loop heat exchangers , 1999 .

[9]  M. Bernier,et al.  Freezing of geothermal borehole surroundings: A numerical and experimental assessment with applications , 2012 .

[10]  Zhaohong Fang,et al.  The research on ring-coil heat transfer models of pile foundation ground heat exchangers in the case of groundwater seepage , 2014 .

[11]  Yasuhiro Hamada,et al.  Field performance of an energy pile system for space heating , 2007 .

[12]  Saffa Riffat,et al.  Comparison of a modelled and field tested piled ground heat exchanger system for a residential building and the simulated effect of assisted ground heat recharge , 2010 .

[13]  Michel Bernier,et al.  Heat Transfer in Double U-Tube Boreholes With Two Independent Circuits , 2011 .

[14]  Tariq Muneer,et al.  Higher ground source heat pump COP in a residential building through the use of solar thermal collectors , 2015 .

[15]  Norman K. Muraya,et al.  Numerical Modeling of the Transient Thermal Interference of Vertical U-Tube Haet Exchangers , 1994 .

[16]  Daniel Pahud,et al.  Numerical evaluation of thermal response tests , 2007 .

[17]  K. Allaerts,et al.  Hybrid ground-source heat pump system with active air source regeneration , 2015 .

[18]  O. J. Zobel,et al.  Heat conduction with engineering, geological, and other applications , 1955 .

[19]  E Sailer,et al.  Assessment of Design Procedures for Vertical Borehole Heat Exchangers , 2015 .

[20]  Per Eskilson.  Thermal analysis of heat extraction boreholes , 1987 .

[21]  Donggen Peng,et al.  A review on thermal response test of ground-coupled heat pump systems , 2014 .

[22]  Fleur Loveridge,et al.  G-Functions for multiple interacting pile heat exchangers , 2014 .

[23]  J. Claesson,et al.  New Analytical and Numerical Solutions for the Short-term Analysis of Vertical Ground Heat Exchangers , 2011 .

[24]  Heinz Brandl,et al.  Thermo-active Ground-Source Structures for Heating and Cooling , 2013 .

[25]  Arefeh Hesaraki,et al.  Seasonal thermal energy storage with heat pumps and low temperatures in building projects—A comparative review , 2015 .

[26]  Jarek Kurnitski,et al.  Geothermal energy piles and boreholes design with heat pump in a whole building simulation software , 2015 .

[27]  R. J. Hopkirk,et al.  “FRACure” — A simulation code for forced fluid flow and transport in fractured, porous rock , 1995 .

[28]  Xu Zhang,et al.  Thermal performance and ground temperature of vertical pile-foundation heat exchangers: A case study , 2008 .

[29]  Pingfang Hu,et al.  A composite cylindrical model and its application in analysis of thermal response and performance for energy pile , 2014 .

[30]  Shuntaro Inoue,et al.  Experimental study of several types of ground heat exchanger using a steel pile foundation , 2011 .

[31]  Alvin C.K. Lai,et al.  Heat-source solutions to heat conduction in anisotropic media with application to pile and borehole ground heat exchangers , 2012 .

[32]  Antonio Fasano,et al.  Numerical solution of phase-change problems , 1973 .

[33]  Moncef Krarti,et al.  Foundation heat loss from heated concrete slab-on-grade floors , 2001 .

[34]  Daniel Pahud,et al.  The Duct Ground Heat Storage Model (DST) for TRNSYS Used for the Simulation of Heat Exchanger Piles. User Manual, December 1996 Version , 1996 .

[35]  John W. Lund,et al.  Direct utilization of geothermal energy 2010 worldwide review , 2011 .

[36]  Fabrice Dupray,et al.  Numerical analysis of seasonal heat storage in an energy pile foundation , 2014 .

[37]  H. Brandl.  Energy foundations and other thermo-active ground structures , 2006 .

[38]  Biagio Morrone,et al.  Energy and economic savings using geothermal heat pumps in different climates , 2014 .

[39]  Hangseok Choi,et al.  Relative constructability and thermal performance of cast-in-place concrete energy pile: Coil-type GHEX (ground heat exchanger) , 2015 .

[40]  Hongxing Yang,et al.  A new model and analytical solutions for borehole and pile ground heat exchangers , 2010 .

[41]  J. Jokisalo,et al.  Development of weighting factors for climate variables for selecting the energy reference year according to the EN ISO 15927-4 standard , 2012 .

[42]  Thomas Kohl,et al.  System performance of a deep borehole heat exchanger , 2002 .

[43]  Daniel Pahud,et al.  Measured thermal performances of the energy pile system of the Dock Midfield at Zurich airport , 2007 .

[44]  Francesco Reda,et al.  Long term performance of different SAGSHP solutions for residential energy supply in Finland , 2015 .

[45]  Wenke Zhang,et al.  Numerical and analytical analysis of groundwater influence on the pile geothermal heat exchanger with cast-in spiral coils , 2014 .

[46]  H. C. Bixel,et al.  Pressure Drawdown and Buildup in the Presence of Radial Discontinuities , 1967 .

[47]  C. K. Lee,et al.  A simplified model of energy pile for ground-source heat pump systems , 2013 .

[48]  A. Lai,et al.  Review of analytical models for heat transfer by vertical ground heat exchangers (GHEs): A perspective of time and space scales , 2015 .

[49]  Hongxing Yang,et al.  Vertical-borehole ground-coupled heat pumps: A review of models and systems , 2010 .

[50]  Jyrki Kesti,et al.  Geothermal Heat Pump Plant Performance in a Nearly Zero-energy Building , 2016 .

[51]  Dominique Marchio,et al.  Sizing Calculation Spreadsheet Vertical Geothermal Borefields , 2010 .

[52]  E. Hassani Nezhad Gashti,et al.  Numerical modelling of thermal regimes in steel energy pile foundations: A case study , 2014 .

[53]  Fleur Loveridge,et al.  2D thermal resistance of pile heat exchangers , 2014 .

[54]  Li Shao,et al.  Simulation of a domestic ground source heat pump system using a three-dimensional numerical borehole heat exchanger model , 2011 .

[55]  Z. Fang,et al.  A finite line‐source model for boreholes in geothermal heat exchangers , 2002 .