The ability of a soil temperature gradient-based methodology to detect leaks from pipelines in buried district heating channels

Perpar, Matjaž (author), Rek, Zlatko (author)

We carried out several numerical experiments to analyze how different boundary conditions affect the ability to detect small pipeline leaks. Our method is based on determining the soil temperature gradient above a buried district heating channel. The equivalent thermal conductivity of a wet insulation (leq) value of 0.5 W/(m(middot)K) was used to mimic a small water leakage. To evaluate the heat loss through the channel cross section, the heat conduction model was used for the pipe insulation, the concrete, and the soil, while the convection model was considered within the channel. The following effects were used to simulate different operating conditions: heat convection at the soil surface, leakage only from the supply or return pipe, soil height above the channel, soil thermal conductivity, and pipe diameter. With the exception of leakage only from the return pipe and low soil thermal conductivity 0.4 W/(m(middot)K), the results showed a doubling of the soil temperature gradient when compared with the no-leakage case. This fact undoubtedly confirms the potential of the method, which is particularly suitable for leak detection in old pipelines that have priority for renovation. A key added value of this research is that the soil temperature gradient-based leak detection technique was found useful in most foreseeable DH operating situations.

• Language: English
• Keywords: district heating network, heat losses, numerical experiment, soil temperature gradient, water leak, detection method robustness
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: Str. 1-12
• Numbering: Vol. 14, iss. 18, art. 5712
• PID: 20.500.12556/RUL-130538
• UDC: 696.46:628.8:519.6
• ISSN on article: 1996-1073
• DOI: 10.3390/en14185712
• COBISS.SI-ID: 76561155
• Publication date in RUL: 16.09.2021

Record is a part of a journal

• Title: Energies
• Shortened title: Energies
• Publisher: Molecular Diversity Preservation International
• ISSN: 1996-1073
• COBISS.SI-ID: 518046745

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 10.09.2021

Secondary language

• Language: Slovenian
• Keywords: omrežje daljinskega ogrevanja, toplotne izgube, numerični eksperiment, temperaturni gradient v zemljini, puščanje vode, robustnost detekcijske metode

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0162
• Name: Tranzientni dvofazni tokovi

• Funder: Other - Other funder or multiple funders
• Funding programme: JP Energetika Ljubljana, d. o. o.
• Project number: JPE-SCV-49/11
• Name: Izdelava fizikalnega modela za določanje toplotnih izgub na vročevodnem omrežju sistema daljinskega ogrevanja v Ljubljani