Thermal performance of a single U-tube ground heat exchanger: A parametric study

Abstract

In this research, the thermal performance of a single U-tube vertical ground heat exchanger is evaluated numerically as a function of the most influential flow parameters, namely, the soil porosity, volumetric heat capacity, and thermal conductivity of the backfill material, inlet volume flow rate, and inlet fluid temperature. The results are discussed in terms of the variations of the heat exchange rate, the effective thermal resistance, and the effectiveness of the ground heat exchanger. They show that the inlet volume flow rate, inlet fluid temperature, and backfill material thermal conductivity have significant effects on the thermal performance of the ground heat exchanger, such that by decreasing the inlet volume flow rate and increasing the backfill material thermal conductivity and inlet fluid temperature, the outlet fluid temperature decreases considerably. On the contrary, the soil porosity and backfill material volumetric heat capacity have negligible effects on the studied ground heat exchanger’s thermal performance. The lowest inlet fluid temperature reaches a the maximum effective thermal resistance of borehole and soil, and consequently the minimum heat transfer rate and effectiveness. Also, multilinear regression analyses are performed to determine the most feasible models able to predict the thermal properties of the single U-tube ground heat exchanger.

Keywords

single U-tube ground heat exchanger / numerical simulation / heat exchange rate / effectiveness / multilinear regression analysis

References

[1] NorouziA M, SiavashiM, KhalijiO M. Efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles [J]. Renewable Energy, 2020, 145: 569-584

[2] SiavashiM, GhasemiK, YousofvandR, DerakhshanS. Computational analysis of SWCNH nanofluid-based direct absorption solar collector with a metal sheet [J]. Solar Energy, 2018, 170: 252-262

[3] NorouziA M, SiavashiM, AhmadiR, TahmasbiM. Experimental study of a parabolic trough solar collector with rotating absorber tube [J]. Renewable Energy, 2021, 168: 734-749

[4] AckermannT. Wind energy technology and current status: A review [J]. Renewable and Sustainable Energy Reviews, 2000, 4(4): 315-374

[5] RehmanS, Al-HadhramiL M, AlamM M. Pumped hydro energy storage system: A technological review [J]. Renewable and Sustainable Energy Reviews, 2015, 44: 586-598

[6] BertaniR. Geothermal power generation in the world 2010–2014 update report [J]. Geothermics, 2016, 60: 31-43

[7] ZhengM, LiB-y, QiaoZ-yong. Case study of underground pipe ground coupled heat pump system [J]. Journal of Central South University, 2012, 19(3): 664-668

[8] WangF-h, FengC-c, YanL, WangX-ke. Numerical and experimental evaluation on methods for parameter identification of thermal response tests [J]. Journal of Central South University, 2012, 19(3): 816-823

[9] JavadiH, MousaviA S S, RosenM A, PourfallahM. Performance of ground heat exchangers: A comprehensive review of recent advances [J]. Energy, 2019, 178: 207-233

[10] SunF-r, YaoY-d, LiG-zhen. Literature review on a U-shaped closed loop geothermal energy development system [J]. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020, 42(22): 2794-2806

[11] SaniA K, SinghR M, AmisT, CavarrettaI. A review on the performance of geothermal energy pile foundation, its design process and applications [J]. Renewable and Sustainable Energy Reviews, 2019, 106: 54-78

[12] JavadiH, MousaviA S S, PourfallahM, ZaboliM. Performance analysis of helical ground heat exchangers with different configurations [J]. Applied Thermal Engineering, 2019, 154: 24-36

[13] NoorollahiY, SaeidiR, MohammadiM, AmiriA, HosseinzadehM. The effects of ground heat exchanger parameters changes on geothermal heat pump performance — A review [J]. Applied Thermal Engineering, 2018, 129: 1645-1658

[14] ArestiL, ChristodoulidesP, FloridesG. A review of the design aspects of ground heat exchangers [J]. Renewable and Sustainable Energy Reviews, 2018, 92: 757-773

[15] GaoJ-j, LiA-b, XuX-h, GangW-j, YanT. Ground heat exchangers: Applications, technology integration and potentials for zero energy buildings [J]. Renewable Energy, 2018, 128: 337-349

[16] JavadiH, UrchueguiaJ F, MousaviA S S, BadenesB. Numerical study on the thermal performance of a single U-tube borehole heat exchanger using nano-enhanced phase change materials [J]. Energies, 2020, 13(19): 5156

[17] CuiY-l, ZhuJ, TwahaS, RiffatS. A comprehensive review on 2D and 3D models of vertical ground heat exchangers [J]. Renewable and Sustainable Energy Reviews, 2018, 94: 84-114

[18] YanT, XuX-hua. Utilization of ground heat exchangers: A review [J]. Current Sustainable/Renewable Energy Reports, 2018, 5(2): 189-198

[19] JavadiH, MousaviA S, RosenM, PourfallahM. A comprehensive review of backfill materials and their effects on ground heat exchanger performance [J]. Sustainability, 2018, 10(12): 4486

[20] Sáez BlázquezC, Farfán MartínA, Martín NietoI, Carrasco GarcíaP, Sánchez PérezL, González-AguileraD. Efficiency analysis of the main components of a vertical closed-loop system in a borehole heat exchanger [J]. Energies, 2017, 102201

[21] KimD, KimG, KimD, BaekH. Experimental and numerical investigation of thermal properties of cement-based grouts used for vertical ground heat exchanger [J]. Renewable Energy, 2017, 112260-267

[22] CaoS-j, KongX-r, DengY-l, ZhangW-r, YangL-y, YeZ-ping. Investigation on thermal performance of steel heat exchanger for ground source heat pump systems using full-scale experiments and numerical simulations [J]. Applied Thermal Engineering, 2017, 11591-98

[23] YoonS, LeeS R, GoG H. A numerical and experimental approach to the estimation of borehole thermal resistance in ground heat exchangers [J]. Energy, 2014, 71: 547-555

[24] YangW-b, ZhangS-s, ChenY-ping. A dynamic simulation method of ground coupled heat pump system based on borehole heat exchange effectiveness [J]. Energy and Buildings, 2014, 77: 17-27

[25] LiX-y, LiT-y, QuD-q, YuJ-wen. A new solution for thermal interference of vertical U-tube ground heat exchanger for cold area in China [J]. Geothermics, 2017, 65: 72-80

[26] SandlerS, ZajaczkowskiB, BialkoB, MalechaZ M. Evaluation of the impact of the thermal shunt effect on the U-pipe ground borehole heat exchanger performance [J]. Geothermics, 2017, 65: 244-254

[27] FloridesG, TheofanousE, Iosif-StylianouI, TassouS, ChristodoulidesP, ZomeniZ, TsiolakisE, KalogirouS, MessaritisV. Modeling and assessment of the efficiency of horizontal and vertical ground heat exchangers [J]. Energy, 2013, 58: 655-663

[28] LiuF, GuoT, WangY, WengM-cheng. Numerical simulation on heat transfer performance of vertical U-tube with different borehole fill materials [J]. Journal of Central South University of Technology, 2006, 13(3): 234-237

[29] PuL, QiD, LiK, TanH-b, LiY-zhong. Simulation study on the thermal performance of vertical U-tube heat exchangers for ground source heat pump system [J]. Applied Thermal Engineering, 2015, 79: 202-213

[30] ChoiH K, YooG J, LimK B, LeeS H, LeeC H. Thermal performance analysis of borehole size effect on geothermal heat exchanger [J]. Journal of Central South University, 2012, 19(12): 3524-3529

[31] WitteH. A parametric sensitivity study into borehole performance design parameters [C]. Proceedings of 12th International Conference on Energy Storage, 2012, Lleida, Spain, INNOSTOCKINNO-U-33

[32] CasassoA, SethiR. Efficiency of closed loop geothermal heat pumps: A sensitivity analysis [J]. Renewable Energy, 2014, 62: 737-746

[33] CasassoA, SethiR. Sensitivity analysis on the performance of a ground source heat pump equipped with a double U-pipe borehole heat exchanger [J]. Energy Procedia, 2014, 59: 301-308

[34] ZanchiniE, JahanbinA. Effects of the temperature distribution on the thermal resistance of double u-tube borehole heat exchangers [J]. Geothermics, 2018, 71: 46-54

[35] JahanbinA, SempriniG, NataleI A, BiserniC, RossiD S E. Effects of the circuit arrangement on the thermal performance of double U-tube ground heat exchangers [J]. Energies, 2020, 13(12): 3275

[36] ZhuL, ChenS, YangY, SunY. Transient heat transfer performance of a vertical double U-tube borehole heat exchanger under different operation conditions [J]. Renewable Energy, 2019, 131: 494-505

[37] KermeE D, FungA S. Heat transfer simulation, analysis and performance study of single U-tube borehole heat exchanger [J]. Renewable Energy, 2020, 1451430-1448

[38] KermeE D, FungA S. Transient heat transfer simulation, analysis and thermal performance study of double U-tube borehole heat exchanger based on numerical heat transfer model [J]. Applied Thermal Engineering, 2020, 173: 115189

[39] ZhangC-x, WangX-j, SunP-k, KongX-q, SunS-cai. Effect of depth and fluid flow rate on estimate for borehole thermal resistance of single U-pipe borehole heat exchanger [J]. Renewable Energy, 2020, 1472399-2408

[40] VellaC, BorgS P, MicallefD. The effect of shank-space on the thermal performance of shallow vertical U-tube ground heat exchangers [J]. Energies, 2020, 13(3): 602

[41] RabaniM, MadessaH B, TorgersenJ, NordN. Parametric analysis of ground source heat pump system for heating of office buildings in Nordic climate [C]. Proceedings of International Conference of BuildSIM-Nordic, 2020, Norway, IBPSA-Nordic

[42] ZhangH-z, HanZ-w, YangL-y, YuanJ-w, ChengX-l, JiM-z, LiG. Analysis of influence of the length of ground heat exchangers on the operation characteristics and economy of ground source heat pumps [J]. Energy and Built Environment, 2021, 22127-136

[43] BejanAConvection heat transfer [M], 2013, Hoboken, NJ, USA, John Wiley & Sons, Inc.

[44] MajidS, MohammadJ. Optimal selection of annulus radius ratio to enhance heat transfer with minimum entropy generation in developing laminar forced convection of water-Al₂O₃ nanofluid flow [J]. Journal of Central South University, 2017, 24(8): 1850-1865

[45] MOUSAVI AJAROSTAGHI S S, SHIRZAD M, RASHIDI S, LI L K B. Heat transfer performance of a nanofluid-filled tube with wall corrugations and center-cleared twisted-tape inserts [J]. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020: 1 -21. DOI: https://doi.org/10.1080/15567036.2020.1841860.

[46] SaffarianM R, MoravejM, DoranehgardM H. Heat transfer enhancement in a flat plate solar collector with different flow path shapes using nanofluid [J]. Renewable Energy, 2020, 146: 2316-2329

[47] BozorgM V, HosseinD M, HongK, XiongQ-gang. CFD study of heat transfer and fluid flow in a parabolic trough solar receiver with internal annular porous structure and synthetic oil-Al₂O₃ nanofluid [J]. Renewable Energy, 2020, 145: 2598-2614

[48] SiavashiM, KarimiK, XiongQ-g, DoranehgardM H. Numerical analysis of mixed convection of two-phase non-Newtonian nanofluid flow inside a partially porous square enclosure with a rotating cylinder [J]. Journal of Thermal Analysis and Calorimetry, 2019, 137(1): 267-287

[49] ZengH-y, DiaoN-r, FangZ-hong. Efficiency of vertical geothermal heat exchangers in the ground source heat pump system [J]. Journal of Thermal Science, 2003, 12(1): 77-81

[50] ChenS-y, MaoJ-f, HanX. Heat transfer analysis of a vertical ground heat exchanger using numerical simulation and multiple regression model [J]. Energy and Buildings, 2016, 129: 81-91

[51] SiavashiM, MiriJ S M. Numerical performance analysis of a counter-flow double-pipe heat exchanger with using nanofluid and both sides partly filled with porous media [J]. Journal of Thermal Analysis and Calorimetry, 2019, 135(2): 1595-1610

[52] PourrahmaniH, MoghimiM, SiavashiM, ShirbaniM. Sensitivity analysis and performance evaluation of the PEMFC using wave-like porous ribs [J]. Applied Thermal Engineering, 2019, 150: 433-444

[53] HeyhatM M, MousaviS, SiavashiM. Battery thermal management with thermal energy storage composites of PCM, metal foam, fin and nanoparticle [J]. Journal of Energy Storage, 2020, 28: 101235

[54] AjarostaghiS S M, DelavarM A, PoncetS. Thermal mixing, cooling and entropy generation in a micromixer with a porous zone by the lattice Boltzmann method [J]. Journal of Thermal Analysis and Calorimetry, 2020, 140(3): 1321-1339

[55] RashidiS, EsfahaniJ A, KarimiN. Porous materials in building energy technologies—A review of the applications, modelling and experiments [J]. Renewable and Sustainable Energy Reviews, 2018, 91229-247

[56] RashidiS, KashefiM H, KimK C, Samimi-AbianehO. Potentials of porous materials for energy management in heat exchangers — A comprehensive review [J]. Applied Energy, 2019, 243: 206-232

[57] RashidiS, HormoziF, DoranehgardM H. Abilities of porous materials for energy saving in advanced thermal systems [J]. Journal of Thermal Analysis and Calorimetry, 2021, 143(3): 2437-2452

[58] BaraghS, ShokouhmandH, AjarostaghiS S M, NikianM. An experimental investigation on forced convection heat transfer of single-phase flow in a channel with different arrangements of porous media [J]. International Journal of Thermal Sciences, 2018, 134: 370-379

[59] BaraghS, ShokouhmandH, AjarostaghiS S M. Experiments on mist flow and heat transfer in a tube fitted with porous media [J]. International Journal of Thermal Sciences, 2019, 137: 388-398

[60] SuryatriyastutiM E, MrouehH, BurlonS. A load transfer approach for studying the cyclic behavior of thermo-active piles [J]. Computers and Geotechnics, 2014, 55: 378-391

[61] JavadiH, AjarostaghiS S M, MousaviS S, PourfallahM. Thermal analysis of a triple helix ground heat exchanger using numerical simulation and multiple linear regression [J]. Geothermics, 2019, 81: 53-73

[62] JavedS, SpitlerJ. Accuracy of borehole thermal resistance calculation methods for grouted single U-tube ground heat exchangers [J]. Applied Energy, 2017, 187: 790-806

[63] DehkordiS E, SchincariolR A, ReitsmaS. Thermal performance of a tight borehole heat exchanger [J]. Renewable Energy, 2015, 83: 698-704

[64] MarcotteD, PasquierP. On the estimation of thermal resistance in borehole thermal conductivity test [J]. Renewable Energy, 2008, 33(11): 2407-2415

[65] RashidiS, BakhshiN, RafeeR. Progress and challenges of helical-shaped geothermal heat exchangers [J]. Environmental Science and Pollution Research, 2021, 28(23): 28965-28992

[66] MinitabIMINITAB release 17: statistical software for windows [M], 2014, USA, Minitab Inc