Flexible space heating demand for district heating systems – Case study of Gothenburg, Sweden Dmytro Romanchenko July 3rd, 2018 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Main findings Using the thermal mass of buildings as energy storage, i,.e. active demand response, has a significant potential to smoothen heat load variations in District Heating (DH) systems The space heating demand response potential of buildings via 1°C indoor temperature variations is sufficient to significantly effect the heat load of a DH system Reduced variations in the heat load result in improved efficiency of heat generation in DH systems Higher utilization factor of base-load heat generators Decreased number of starts and stops of peak-load heat generators 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Background Energy used for space heating and hot water in single-family, multi-dwelling and non-residential buildings in 2015 https://www.engie.com/en/businesses/district-heating-cooling-systems/ 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Motivation for the research Requirement for the peaking heat generation (usually fossil fuels-based heat-only boilers HOBs) High number of starts and stops Part-load operation Scheduling challenges (HPs and CHP plants) Thermal energy storage, e.g.: Hot water tanks and boreholes Thermochemical storage Active demand response from buildings 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Aim of the research Increase an understanding of how flexible heat demand from buildings can affect the supply side, i.e., operation of DH systems Objective of the research Develop a modelling method, which integrates the calculation of the space heating demand from buildings, by this allowing for demand response, with the dispatch of the investigated DH system Estimate the effects of the ´space heating demand response on the total energy demand and operation of the DH system 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Model development 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Building stock of Gothenburg, Sweden The building stock of Gothenburg is represented by: 28 sample single-family houses (SFHs) ~ extrapolated to 9,700 real SFHs (1.5 mln m2) 66 sample multi-family houses (MFHs) ~ extrapolated to 5,300 real MFHs (15.8 mln m2) 40 sample non-residential buildings (NRBs) ~ extrapolated to 3,600 real NRBs (6.2 mln m2) Description of the sample buildings is extracted from the BETSI study, which comprises 1800 buildings selected to represent the total Swedish buildings stock NRBs are further divided in 5 sub-categories (based on the purpose of the building) 03/07/2018 Chalmers University of Technology

Chalmers University of Technology District heating system of Gothenburg, Sweden Second largest district heating system in Sweden 28 heat generation units 3,300 GWh of heat delivered yearly 1000 km trench length of the network 56% of generated heat stems from industrial excess heat and waste incineration 18% of generated heat stems from renewable energy sources Supplies heat to 90% of all MFHs and 20% of all SFHs in the city 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Results – Heating load with flexible demand response in buildings “Reference” – indoor temperature is fixed – no DR “Tvar 1(ºC)” – DR via upward temperature deviations of up to 1ºC “Tvar 3(ºC)” – DR via upward temperature deviations of up to 3ºC 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Results – Effects of demand response on the heat load variations RDLV a) spring-autumn b) winter “Reference” – indoor temperature is fixed – no DR “Tvar 1(ºC)” – DR via upward temperature deviations of up to 1ºC “Tvar 3(ºC)” – DR via upward temperature deviations of up to 3ºC c) 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Results – Effects of demand response on the operation of units drop by 85% “Reference” – indoor temperature is fixed – no DR “Tvar 1(ºC)” – DR via upward temperature deviations of up to 1ºC “Tvar 3(ºC)” – DR via upward temperature deviations of up to 3ºC 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Conclusions and remarks The potential of demand response from buildings is investigated by means of the overheating of buildings by 1ºC and 3ºC The demand response from buildings has a significant impact on the total system heat load: Decreased number and amplitude of heat load variations Improved operation of heat generation units Decreased cost of heat generation Developed optimisation modelling is generic and applicable to other DH systems and building stocks 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Remarks and future work Improve representation of the hot water and industrial loads in the modelling Apply both upward and downward temperature deviations for studying the potential of DR To study future development of the building stock e.g. implementation of energy conservation measures Test developed modelling on other systems/cities and upscale to the national level Expand heat-oriented research to the total energy load in buildings 03/07/2018 Chalmers University of Technology

Chalmers University of Technology Thank you for your attention! 03/07/2018 Chalmers University of Technology