Impact of thermal masses on the peak load in district heating systems

• Published in: Energy (Oxford) Vol. 214; p. 118849
• Main Author: Guelpa, Elisa
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2021; Elsevier BV
• Subjects: Advanced operations; District heating; District heating network; Electrical transmission; Energy conservation; Heat; Heat exchangers; Heating; Heating systems; Peak load; Radiators; Shutdowns; Storage; Substations; Temperature; Temperature variation; Thermal capacity; Thermal networks; Thermal storage; Thermal capacity; Storage; Advanced operations; Thermal networks; District heating network; Temperature variation
• DOI: 10.1016/j.energy.2020.118849
• ISSN: 0360-5442

During district heating operations, part of the heat supplied to the network is used to increase the temperature of the various components (e.g. transport and distribution networks, heat exchangers installed in the substations, heating circuits and heating devices in buildings). The mass of these components acts as a thermal storage, storing heat when their temperature increases and releasing heat when they cool down. The impact may become significant, especially during shutdown or setback. In this paper, the components are analyzed in order to estimate the impact of their thermal capacity on the district heating demand. This provides a clear image of the additional supply used to heat the other thermal masses, that can be managed differently since partially independent from the indoor temperature. Results show that in the case study analyzed, i.e. large system mainly switched off during night, the heat absorbed by the thermal masses corresponds to the 4% of the heat supplied during the entire day and 70% of the heat provided during the peak. The various thermal masses affect the extra heat absorbed to a similar extent (except for radiators). Results provide a clue that proper management of thermal masses for energy saving might be considered. [Display omitted] •Thermal masses of district heating network components are analyzed independently.•In case of night shutdown, capacities affecting peak formation are quantified.•An existing large-scale network (Turin, Italy) is used as case study.•Capacity of buildings makes only a partial contribution in peak formation.•Distribution networks and building circuits are the major extra thermal masses.