12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaNEW ECONOMICAL CONNECTION SOLUTION FOR FLEXIBLE PIPING SYSTEMSChristian Engel, Gerrit-Jan BaarsThermaflex <strong>International</strong> Holding B.V.ABSTRACTMost Energy Companies are facing the same problem:Connection costs per house shall be cheaper andfaster to install to reach more customers. At the sametime high level of durability and a system free ofmaintenance must be guaranteed.This paper shall give an insight of the practicalexperience with new solutions showing the economicand ecological advantages in projects with severalEnergy companies.INTRODUCTIONDistrict Heating & Cooling networks are a major costfactor for Energy Providers and subject to permanentsearch for cost improvements.Flexible plastic pipe systems have been a major stepfor cost reduction in low temperature networks. Withthe new EN 15632 [1] the necessary basis forcertification of these systems has been laid. This is amilestone in terms of acknowledgement for flexiblesystems as a proven part of future networkdevelopments.As flow temperatures and pressures are reduced, thefield of application for flexible plastic systems isincreasing. Until recently only a small percentage ofDistrict Heating companies have started to use plasticpipes in their networks. These were kind of pioneerswho co-created systems together with the industry.Together with the University of Leoben, the long termdurability of two types of plastic medium pipes, made ofPB and PE-X were investigated. The research made byDipl.Ing. E.Kramer and Univ.Prof.Dr.J. Koppelmann [2]was based on OIT (oxygen induction time), tearstrength, elongation at break and internal pressuretests to determine the lifetime of plastic pipes at 80, 95and 110 °C. The final results were in favour for pipesmade of PB. The calculation of the lifetime for PB pipeswas based on a typical temperature profile used insecondary district heating networks of STEWEAG. Thelifetime expectancy was stated with 36 years.The decision of STEWEAG was made for PB pipes dueto their more homogenous structure, superior flexibilityand allowance for welded joints. More than 250 km ofthis system have been installed since 1981 insecondary networks operated by STEWEAG. See alsoUniv. Prof. Dr. E. Hönninger, STEWEAG [6].WHAT CAN BE SOLVED WITH FLEXIBLE PLASTICSYSTEMSApart from the high and long term investment costs, thefollowing main problems had to be solved as well:Corrosion problems in conventional Systems madeof Steel/PUR/PE or Cu/PUR/PE or Cu/Mineralwool/PEHeat loss due to wet and aged insulationSystem shut downs for maintenance and repairThe first co-development of such a system was startedalready in 1980 by the Austrian Electricity companySTEWEAG. They were looking for a pre-insulatedpiping system as easy to install as an electric cable.Photo no.: 2 corroded steel pipe connectionTHE NEW FLEXIBLE PIPE GENERATIONPhoto no.:1 first Flexalen installation 1981In 2001 the Dutch Energy Provider NUON started adevelopment co-operation with Thermaflex to createeven more flexible and moisture resistance pipingsystems. Target was again to reduce the connectioncosts for new district heating projects. The new system261