Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Optimal conditions for accelerated thermal ageing of district heating pipes
Technical lifetime prediction of polymeric materials is often based on accelerated ageing tests at elevated temperatures. Samples are exposed to relatively high temperatures to accelerate the natural degradation processes. For district heating pipes, accelerated thermal ageing is the ordinary method used to determine the lifetime of pipes. According to the Standard EN 253:2009 + A1:2013, the district heating pipes shall be subjected to an accelerated thermal ageing for a long period of time at 160 °C or 170 °C. The lifetime is determined by extrapolation using the Arrhenius relationship. However, papers published recently have questioned this method, especially the high temperatures used for ageing of the pipes and the use of Arrhenius equation to describe the complicated degradation mechanisms, which can result in the erroneous estimation of the technical lifetime. Our investigation has shown the complexity of the pipe's degradation mechanisms. The behaviour of mechanical shear strength at elevated temperatures (T > 130 °C), suggests an alteration rather than an acceleration of the degradation mechanisms. Accelerated ageing tests should reproduce the proper natural ageing mechanisms. The analyses of PUR's thermal conductivity and its chemical structure by FTIR confirmed the degradation patterns
Optimal conditions for accelerated thermal ageing of district heating pipes
Technical lifetime prediction of polymeric materials is often based on accelerated ageing tests at elevated temperatures. Samples are exposed to relatively high temperatures to accelerate the natural degradation processes. For district heating pipes, accelerated thermal ageing is the ordinary method used to determine the lifetime of pipes. According to the Standard EN 253:2009 + A1:2013, the district heating pipes shall be subjected to an accelerated thermal ageing for a long period of time at 160 °C or 170 °C. The lifetime is determined by extrapolation using the Arrhenius relationship. However, papers published recently have questioned this method, especially the high temperatures used for ageing of the pipes and the use of Arrhenius equation to describe the complicated degradation mechanisms, which can result in the erroneous estimation of the technical lifetime. Our investigation has shown the complexity of the pipe's degradation mechanisms. The behaviour of mechanical shear strength at elevated temperatures (T > 130 °C), suggests an alteration rather than an acceleration of the degradation mechanisms. Accelerated ageing tests should reproduce the proper natural ageing mechanisms. The analyses of PUR's thermal conductivity and its chemical structure by FTIR confirmed the degradation patterns
Optimal conditions for accelerated thermal ageing of district heating pipes
Vega, Alberto (Autor:in) / Yarahmadi, Nazdaneh (Autor:in) / Jakubowicz, Ignacy (Autor:in)
01.01.2018
doi:10.1016/j.egypro.2018.08.171
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
accelerated ageing , Degradation mechanisms , district heating pipes , rigid polyurethane foam , Chemical analysis , Degradation , District heating , Testing , Thermal aging , Accelerated ageing tests , Arrhenius relationship , Degradation mechanism , Degradation patterns , Elevated temperature , Natural degradation , Rigid polyurethane foams , Thermal conductivity , Natural Sciences , Naturvetenskap
Accelerated ageing of plastic jacket pipes for district heating
| British Library Online Contents | 2016
Accelerated ageing of plastic jacket pipes for district heating
| British Library Online Contents | 2016