Diagnostic Protocol for Thermal Performance of District Heating Pipes in Operation. Part 2: Estimation of Present Thermal Conductivity in Aged Pipe Insulation

Peter Lidén, Bijan Adl-Zarrabi and Carl-Eric Hagentoft
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Peter Lidén: Department of Architecture and Civil Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
Bijan Adl-Zarrabi: Department of Architecture and Civil Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
Carl-Eric Hagentoft: Department of Architecture and Civil Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden

Energies, 2021, vol. 14, issue 17, 1-15

Abstract: Buried and operating district heating (DH) pipes are exposed to thermal degradation of their polyurethane (PUR) insulation over time, and their status is hard to assess without excavation. By using DH pipe valves in manholes as measurement points during a shutdown with an ensuing cooling period, non-destructive assessments can be performed. This study compares new improved field measurements with numerical simulations of the temperature decline in drainage valves and shutdown valves. The drainage valve measurements were used to thermally assess part of a buried DH network. Results indicate that by using the drainage valves as measurement points in a cooling method, the thermal conductivity of the buried DH network could be predicted with an accuracy of >95%. In addition, a general diagnostic protocol has been established for assessing the thermal status of a DH network, ready for network owners to use.

Keywords: district heating network; heat losses; non-destructive testing; cooling method; valve; thermal conductivity; polyurethane; thermal status (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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