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, EstoniaFig. 1 network scheme suitable for T-LinkEspecially for networks with short distances betweenthe branches and the connection to the houses, a highdegree of pre-fabrication can be offered.One solution is the T-Link as described before. Anotherone can be a main line up to 100 m with factory weldedand insulated Tees. This reduces the work on site tojust 1 welding for the house connection line. Thissolution is interesting for longer distance houseconnections.THE IMPORTANCE OF THE NETWORK DESIGNFlexible PB piping systems offer important advantagescompared to other plastic and steel systems in terms oflayout and design.Compared to steel pipes flexible PB systems can belaid more direct as the system is flexible and fully selfcompensating.Expansion loops and elbows can besaved. The saving in pipe length can be calculated with7–10%.PB systems offer low friction loss and show nocalcification or incrustation during the lifetime. Thepolyfusion welded fittings have at least the same innerdiameter as the pipe and offer the same high abrasionresistance. Taking this into account, some extrasecurity factors used in pipe dimensioning can beeliminated.265PB systems can be operated with much higher flowspeed; hence smaller dimensions can be used for thesame load requirement. See also J. Korsman, I.M.Smits, E. van der Ven [4].With relation to the topic of this paper, the followingadditional savings can be made during the networkdesign: Looking for a new building area, mostly streets withblock of houses there are two possibilities:Installing under the floor or Installing in the streets. For every house connection under the floor onlytwo welds and two insulation sets are necessary.Reduction of the installing time/costs by 50–60%. For every house connection in the street, apre-fabrication e.g. for 8–10 house-connectionsbuilt in into one 100m coil can safe installingtime/costs totally including excavating the trenchesof 70%Taking all these possibilities for savings andoptimization into account, the next most important topicfor Energy Provider, the efficiency of the network inoperation, can be tackled as well. Due to the possiblereduction in network length and pipe diameter, theoverall heat loss can be reduced as well. See alsoresults from the work of I.M. Smits, J. Korsman, J.T.van Wijnkoop and E.J.H.M. van der Ven [5] and J.T.van Wijnkoop, E.J.H.M. van der Ven [3].