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, EstoniaThe actual effect of SlimNet on heat losses will beclosely monitored in the grid, through the strategicmetering project.SlimNet part II: Smart chain managementThe last heat loss parameter, fluid temperature (Eq. 6),can only be changed by modification of the completechain.To start at the production side, the current supplytemperature is dependent on the ambient temperature,95 C at Ta=-10 C and 75 C at Ta=15 C, Fig. 6.Lowering this curve, while still meeting therequirements of customer installations, would reducethe average network temperature hence the heatlosses. It was calculated through the network modelthat the alternative temperature curve in Fig. 6 solelywould reduce the heat losses with 4%. Furtherresearch will focus on matching the most effectivetemperature curve with production characteristics.houses that have a 90–50 C characteristic duringdesign conditions (-10 C). In most areas before thattime SVP found return temperatures that arestructurally higher than the required 50 C. Hence theflows in those areas are also much higher thannecessary.The high return temperatures and corresponding highflows are caused by absence of pressurizing valves inthe customer installations and defective control valvesin the hot tapping water installations. By the end of2010 SVP starts a campaign to encourage houseowners to improve or renew their installations, also fortheir own benefit. This campaign will make use of localapproved installers of customer installations. Researchindicated that in certain areas the peak flow can bereduced with 60% [9].QUANTIFYING KPI RESULTS FROM SLIMNETSummarized, the measures that SVP takes before2014 to improve network efficiency:1. Renewing the distribution pipes and houseconnections in the crawl spaces of 4000houses, while optimized to dimensions andlengths.2. Replacing 4,0 km PEX-pipes in the primarynetwork, while optimized to dimensions andlengths.3. Doing this with a minimum of off-time forcustomers4. Implementing demand-driven heat productionFig. 6 Existing and alternative temperature curveThis research will also look upon the possibilities ofimplementing demand-driven heat production. This isachieved by using a real time network modelconnected to the substations and production SCADA.The model uses the weather forecast with customerinformation to adjust the temperatures and pressuresjust to meet the requirements of customer installations.It is expected that this will reduce the average fluidtemperature even more.Further research is done to implement cascadingheating services, i.e. using the latent heat in the returnpipes of the network with temperatures between 45 Cand 60 C to the customer installations. This ishowever only possible to implement in new houses withlow temperature heating installations. This research willfocus on further reducing the heat losses.5. Implementing cascaded heating installations6. Encourage house owners to improve or renewtheir installations in accordance with SVPguidelines.7. Eliminating arrears of maintenance animplementing a structural preventativemaintenance program.Heat losses will reduce from 33,6% in 2008 to 22,1% in2015. While heat consumption prognoses stays thesame, the corresponding required heat production falls,Fig. 8. This results in a energy saving of 227.000 GJthat year. In Fig. 9 the results of the sustainabilityassessment model are shown regarding CO2 savings.At the other end of the chain are the customerinstallations. Since 1996 the district heating company inPurmerend has only accepted installations in new58