12th International Symposium on District Heating and Cooling
12th International Symposium on District Heating and Cooling
12th International Symposium on District Heating and Cooling
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The <str<strong>on</strong>g>12th</str<strong>on</strong>g> <str<strong>on</strong>g>Internati<strong>on</strong>al</str<strong>on</strong>g> <str<strong>on</strong>g>Symposium</str<strong>on</strong>g> <strong>on</strong> <strong>District</strong> <strong>Heating</strong> <strong>and</strong> <strong>Cooling</strong>,September 5 th to September 7 th , 2010, Tallinn, Est<strong>on</strong>iaRESULT BASED FUTURE DEVELOPMENTSThe tests have led to improvements to the flexibleplastic pipe products produced by Thermaflex. In thenear future we expect improvements in:Producti<strong>on</strong> methods:Starting June 2010 a change in the machinec<strong>on</strong>figurati<strong>on</strong> will be implemented as an extra step. Thenew c<strong>on</strong>figurati<strong>on</strong> improves temperature c<strong>on</strong>trol in theextruder, which leads to better cell structure.Chemical <strong>and</strong> physical compositi<strong>on</strong> of layer material:Up to a certain degree the anti-radiati<strong>on</strong> agentimproves isolating values. With trial <strong>and</strong> error the antiradiati<strong>on</strong>agent c<strong>on</strong>tent is increased. Up till now themaximum c<strong>on</strong>tent has been limited by producti<strong>on</strong>methods. Research is required to investigate maximumdesired value for insulating effects.Cell structure <strong>and</strong> gap between foam <strong>and</strong> medium pipe:In the tests we see variati<strong>on</strong>s in cell structure <strong>and</strong> gapwidth. Future research will aim at acquiring moredetailed knowledge of these phenomena.Up till now the heat loss performance <strong>on</strong> single pipeshas been measured <strong>and</strong> analysed. This has resulted inan underst<strong>and</strong>ing of the heat loss principles in districtheating systems. Twin pipe systems will so<strong>on</strong> betested, analysed <strong>and</strong> evaluated.In this paper <strong>on</strong>ly the heat loss of the Flexalen 600 preinsulatedpipe product has been h<strong>and</strong>led. Informati<strong>on</strong>about the system can be read in [4] Heat lossoptimizati<strong>on</strong> of flexible plastic piping systems, life timeheat loss performance (Korsman et al) <strong>and</strong> [5] Newec<strong>on</strong>omical c<strong>on</strong>necti<strong>on</strong> soluti<strong>on</strong>s (Engel).CONCLUSIONThe results of testing are reliable. Knowledge of theproduct <strong>and</strong> producti<strong>on</strong> has led to promisingimprovements of both.Further research will certainly lead to furtherdevelopments.Heat loss of buried piping [W/m]31.029.027.025.023.021.019.017.015.0Heat lossHeat loss Degassed50 70 90 110 130 150 170 190Outer diameter pipe system [mm]Graph 5: Degassed heat loss values of a buried system ata temperature difference of 60KExamples of product improvementFurther research has led to product improvements.Based <strong>on</strong> these improvement proposals Thermaflexhas been able to produce new pipe system samples.As represented in graph 5 the new samples have aheat loss decrease up to 16 percent compared to theprevious results.Heat loss of buried piping [W/m]40.035.030.025.020.015.0Heat lossHeat loss New50 70 90 110 130 150 170 190Outer diameter pipe system [mm]Graph 6: New heat loss values of a buried system at atemperature difference of 60KADDENDUMDegassingThe Thermaflex pipe system is liable to the process ofdegassing. Degassing causes the heat loss values torise over the products life time. Extra research <strong>on</strong> thissubject shows an average heat loss increase of9 percent (range 5–13 percent) (graph 5). Heat lossesare calculated according to EN 15632.117
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