Operational planning of low-energy district heating systems connected to existing buildings

H. İ. T. is with Technical University of Denmark, Civil Engineering Department, Copenhagen, DK-2800 Denmark (corresponding author; phone: +45 45 25 50 27; fax: +45 45 88 32 82; e-mail: hatol@byg.dtu.dk).

S. S. Author is with Technical University of Denmark, Civil Engineering Department, Copenhagen, DK-2800 Denmark (e-mail: ss@byg.dtu.dk).

This article focuses on low-energy District Heating (DH) systems operating in low-temperatures such as 55°C in terms of supply and 25°C in terms of return in connection with existing buildings. Since the heat loss from the network has a

significant impact in case of supplying heat to low-energy houses in a traditional DH network, the aim in this paper was given to reduce the dimensions of the low-energy DH network as much as possible. Hence, the performance analyses of the inhouse radiator heating systems equipped in existing buildings were carried out for low temperatures of supply and return. The response of the radiator heating systems at different levels of supply temperature was used to form the operational planning of the low-energy DH system, which determined the design parameters of the low-energy DH network in terms of overall mass flow requirement and the return temperature from the buildings. Since the existing buildings were considered to be renovated to low-energy class, the operational planning was simultaneously modelled for both present high-demand and future low-demand situations of the same case area.

[1] H. Lund et al. "The role of district heating in future renewable energy systems." Energy, vol. 35, pp. 1381-90, Mar. 2010.

[2] P.K. Olsen et al. "A new low-temperature district heating system for low-energy buildings." Int. Symp. on District Heating and Cooling, Reykjavik, Iceland, vol. 11, Aug.-Sep. 2008.

[3] O. Paulsen et al. "Consumer Unit for Low Energy District Heating Net." Int. Symp. on District Heating and Cooling, Reykjavik, Iceland, vol. 11, Aug.-Sep. 2008.

[4] C.H. Christiansen et al. "Development and demonstration of low-energy district heating for low-energy buildings. Main report and appendices," (In Danish) Teknologisk Institut, Århus. EFP 2007, Mar. 2007.

[5] J.E. Thorsen et al. "Experiences on low-temperature district heating in Lystrup - Denmark." Int. Conf. on District Heating and Cooling, Portorož, Slovenia, vol. 12, Sep. 2011.

[6] C.H. Christiansen et al. "Demonstration of low energy district heating system for low energy building in Ringgårdens Afd. 34 in Lystrup," (in Danish) Teknologisk Institut, Århus. EUDP 2008-II, Maj. 2011.

[7] M. Crane. (2011, Nov. 3). SSE zero carbon home development [online]. Available: http://www.ssezerocarbonhomes.com/

[8] A. Hasan et al. "A combined low temperature water heating system consisting of radiators and floor heating." Energy and Buildings, vol. 41, pp. 470-9, May 2009.

[9] H. İ. Tol and S. Svendsen. "Improving the Dimensioning of Piping Networks and Network Layouts in Low-Energy District Heating Systems Connected to Low-Energy Buildings: A Case Study in Roskilde, Denmark." Energy, vol. 38, pp. 276-90, Feb. 2012.

[10] H. İ. Tol and S. Svendsen. "Design of low-energy district heating system for a settlement with low-energy buildings." Int. Symp. on Environmental Management, Zagreb, Croatia, vol. 3, Oct. 2011, pp. 166-71.

[11] T. Karlsson and A. Ragnarsson. "Use of Very Low Temperature Geothermal Water in Radiotor Heating Systems." World Geothermal Congr., Firenze, Italy, vol. 1, May 1995, pp. 2193-8.