Thermal Response Testing Results of Different Types of Borehole Heat Exchangers: An Analysis and Comparison of Interpretation Methods

Zarrella, Angelo; Emmi, Giuseppe; Graci, Samantha; Carli, Michele De; Cultrera, Matteo; Santa, Giorgia Dalla; Galgaro, Antonio; Bertermann, David; Müller, Johannes; Pockelé, Luc; Mezzasalma, Giulia; Righini, Davide; Psyk, Mario; Bernardi, Adriana

doi:10.3390/en10060801

Cited by 40 publications

(29 citation statements)

References 23 publications

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“…The weather definitions explained above are used to create a climate database for integration in the tool used for sizing the Ground Source Heat Pumps (GSHPs) as well as the Decision Support System (DSS) which are developed in the Cheap-GSHPs project [33][34][35].…”

Section: Discussionmentioning

confidence: 99%

A Database for Climatic Conditions around Europe for Promoting GSHP Solutions

et al. 2018

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Abstract:Weather plays an important role for energy uses in buildings. For this reason, it is required to define the proper boundary conditions in terms of the different parameters affecting energy and comfort in buildings. They are also the basis for determining the ground temperature in different locations, as well as for determining the potential for using geothermal energy. This paper presents a database for climates in Europe that has been used in a freeware tool developed as part of the H2020 research project named "Cheap-GSHPs". The standard Köppen-Geiger climate classification has been matched with the weather data provided by the ENERGYPLUS and METEONORM software database. The Test Reference Years of more than 300 locations have been considered. These locations have been labelled according to the degree-days for heating and cooling, as well as by the Köppen-Geiger scale. A comprehensive data set of weather conditions in Europe has been created and used as input for a GSHP sizing software, helping the user in selecting the weather conditions closest to the location of interest. The proposed method is based on lapse rates and has been tested at two locations in Switzerland and Ireland. It has been demonstrated as quite valid for the project purposes, considering the spatial distribution and density of available data and the lower computing load, in particular for locations where altitude is the main factor controlling on the temperature variations.

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Section: Discussionmentioning

confidence: 99%

A Database for Climatic Conditions around Europe for Promoting GSHP Solutions

et al. 2018

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“…For example, Beier maintained that the calculation method of fluid temperature evolution should be consistent in both the test analysis and the design approach [15]; otherwise, significant errors will be introduced to the design. Although there are relevant studies dealing with the comparison of TRT interpretation models [16][17][18], few have concentrated on the influence of TRTPE models on the BHE system design. Are the heat transfer model used in TRT data interpretation and the underlying model in the design calculation based on a consistent assumption?…”

Section: Introductionmentioning

confidence: 99%

Comparison of Four Methods for Borehole Heat Exchanger Sizing Subject to Thermal Response Test Parameter Estimation

Zhang

et al. 2019

Energies

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The impact of different parameter estimation results on the design length of a borehole heat exchanger has received very little attention. This paper provides an in-depth investigation of this problem, together with a full presentation of six data interpretation models and a comprehensive comparison of four representative sizing methods and their inter models. Six heat transfer models were employed to interpret the same thermal response test data set. It was found that the estimated parameters varied with the data interpretation model. The relative difference in borehole thermal resistance reached 34.4%, and this value was 11.9% for soil thermal conductivity. The resulting parameter estimation results were used to simulate mean fluid temperature for a single borehole and then to determine the borehole length for a large bore field. The variations in these two correlated parameters caused about 15% and 5% relative difference in mean fluid temperature in the beginning and at the end of the simulation period, respectively. For computing the borehole design length, software-based methods were more sensitive to the influence of parameter estimation results than simple equation-based methods. It is expected that these comparisons will be beneficial to anyone involved in the design of ground-coupled heat pump systems.

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“…Even though there is already extensive research of implementation of TRT data on optimizing the BHE system, there is space to improve and implement the research, especially when it comes to hydraulic setting. The data set of TR testing, from the Molinella (Bologna) area, was used to appraise the equivalent ground thermal conductivity and in system design [1]. The measured results were examined in accordance with the common interpretation procedure based on the first-order approximation of the solution for the infinite line source (ILS) model and then by utilizing the complete solutions of both the ILS and cylinder source models.…”

Section: Introduction and Literature Overviewmentioning

confidence: 99%

Investigation of Steady-State Heat Extraction Rates for Different Borehole Heat Exchanger Configuration from the Aspect of Implementation of New TurboCollectorTM Pipe System Design

Kurevija¹,

Mehrjerdi²,

Macenić³

et al. 2019

Preprint

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When considering implementation of shallow geothermal energy as a renewable source for heating and cooling of the building, special care should be taken in hydraulic design of borehole heat exchanger system. Laminar flow can occur in pipes due to usage of glycol mixture at low temperature or inadequate flow rate. This can lead to lower heat extraction and rejection rates of the exchanger because of higher thermal resistances. Furthermore, by increasing flow rate to achieve turbulent flow and satisfactory heat transfer rate can lead to increase the pressure drop of the system and oversizing of circulation pump which leads to impairment of seasonal coefficient of performance at the heat pump. Most frequently used borehole heat exchanger system in Europe is double-loop pipe system with smooth inner wall. Lately, development is focused on implementation of different configuration as well as with ribbed inner wall which ensures turbulent flow in the system, even at lower flow rates. At a location in Zagreb, classical and extended thermal response test was conducted on three different heat exchanger configurations in the same geological environment. With classic TRT test, thermogeological properties of the ground and thermal resistance of the borehole were determined for each smooth or turbulator pipe configuration. Extended Steady-State Thermal Response Step Test (TRST) was implemented, which incorporate series of power steps to determine borehole extraction rate at the define steady-state heat transfer conditions of 0/-3°C. Results show that heat exchangers with ribbed inner pipe wall have advantages over classic double-loop smooth pipe design, in terms of greater steady state heat extraction rate and more favorable hydraulic conditions.

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Thermal Response Testing Results of Different Types of Borehole Heat Exchangers: An Analysis and Comparison of Interpretation Methods

Cited by 40 publications

References 23 publications

A Database for Climatic Conditions around Europe for Promoting GSHP Solutions

A Database for Climatic Conditions around Europe for Promoting GSHP Solutions

Comparison of Four Methods for Borehole Heat Exchanger Sizing Subject to Thermal Response Test Parameter Estimation

Investigation of Steady-State Heat Extraction Rates for Different Borehole Heat Exchanger Configuration from the Aspect of Implementation of New TurboCollectorTM Pipe System Design

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