Scholarly record
THERMAL PERFORMANCE OF BOREHOLE HEAT EXCHANGERS FROM NORTHERN TO SOUTHERN EUROPE: A COMPARATIVE STUDY
Abstract
Europe is undergoing a transition toward renewable heating and cooling, and borehole heat exchanger systems play a critical role in this energy shift. However, their efficiency depends heavily on site-specific and local climatic conditions. This study evaluates BHE design and performance across 11 European capital cities that represent diverse climatic conditions, from hot/dry (Nicosia, 21.56 C, undisturbed ground temperature) to cold/humid (Helsinki, 6.76 C). A representative university building was virtually relocated to each city, maintaining identical envelope and operational characteristics to isolate climate and subsurface effects. GLHEPro simulation integrated climate data from Meteonorm and building thermal loads from CitySim Pro, along with site-specific soil thermal properties over a 30-year design period for a rectangular borefield configuration. Results reveal substantial regional variation in required borehole depths, with Helsinki (253.91 m) requiring approximately158% more than Vienna (98.22 m). This disparity was primarily driven by seasonal asymmetry in building thermal loads, compounded by ground thermal conductivity, ground volumetric heat capacity, and undisturbed ground temperature. The analysis indicates that generalized BHE sizing approaches cannot be transferred among regions without substantial site-specific adaptation to local climatic and subsurface conditions. These findings provide practitioners with quantitative insights into regional transferability constraints and site-specific performance indicators to guide robust early-stage development of design tools for distributed renewable heating and cooling across Europe.
Publication details
References11
IRENA (2014), REmap 2030: A Renewable Energy Roadmap, Summary of Findings, June 2014. IRENA, Abu Dhabi. www.irena.org/rema
González-Torres M, Pérez-Lombard L, Coronel JF, Maestre IR, Yan D. A review on buildings energy information: Trends, end-uses, fuels and drivers. Energy Reports 2022;8:626-37. DOI: 10.1016/J.EGYR.2021.11.280.
Roka RB, de Figueiredo AJP, Vieira AMCP, Cardoso JC de P. A systematic review on shallow geothermal energy system: a light into six major barriers. Soils and Rocks 2023;46. DOI: 10.28927/SR.2023.007622.
Choi Y, Lu X, O'Neill Z. Adopting Ground Source Heat Pumps in Commercial Buildings: Nationwide Analysis of Energy Savings and Decarbonization Potentials. Energy Convers Manag 2026;348:120635. DOI: 10.1016/J.ENCONMAN.2025.120635.
ASHRAE, ANSI/ASHRAE Addendum a to ANSI/ASHRAE Standard 169-2020: Climatic Data for Building Design Standards, USA, 2021, ISSN 1041-2336.
Emmanuel W, Jérôme K. A verification of CitySim results using the BESTEST and monitored consumption values. Building Simulation Applications, vol. 2015- Febru, 2015, p. 215-22.
Spitler JD. GLHEPRO-A Design Tool For Commercial Building Ground Loop Heat Exchangers, Oklahoma State University, USA, 2000.
Eskilson P. Thermal Analysis of Heat Extraction Boreholes, PhD Thesis, Lund University, Sweden, 1987, ISBN 91-7900-298-6.
Signorelli S, Kohl T, Rybach L. SUSTAINABILITY OF PRODUCTION FROM BOREHOLE HEAT EXCHANGER FIELDS. PROCEEDINGS, Twenty-Ninth Workshop on Geothermal Reservoir Engineering, USA, 2004, SGP-TR-175.
Bernier MA, Pinel P, Labib R, Paillot R. HVAC&R Research A Multiple Load Aggregation Algorithm for Annual Hourly Simulations of GCHP Systems 2011. DOI: 10.1080/10789669.2004.10391115.
Cimmino M, Bernier M, Adams F. A contribution towards the determination of g-functions using the finite line source. Appl Therm Eng 2013;51:401-12. DOI: 10.1016/J.APPLTHERMALENG.2012.07.044.