Low Temperature and Cold District Heating & Cooling Systems Transition, Implementation, Planning, Long-term Evaluation Lorenz Leppin, Hermann Edtmayer, Harald Schrammel, Ingo Leusbrock 1 Introduction District heating plays a central role in the Austrian energy supply scheme and already covers 25% of the national heat demand. On a European level district heating was identifi ed as one of Motivation the key technologies to drive the transition towards a decarbonized, effi cient, sustainable and Cold heat is characterized by supply fossil-free energy system. The recent development of district heating systems shows a decrease temperatures below 30°C. That makes it in supply temperatures and an increase in the share of renewable energy sources in the system. particularly suitable for using renewable energy sources and low-temperature heat from other Share of Renewables in DHC Network local sources. Another positive side effect is that heat losses in the grid are minimized and novel 300 °C 1st Generation – Steam pipes in ducts. Up to 20 bar and 300°C polymeric materials for piping can be used. The high degree of fl exibility allows for expansion 130 °C nd – Hot water pipes in ducts 2 Generation and later integration of additional sources, 90 °C 3rd Generation – Hot water pipes directly buried, all-bonded sinks and storages. Compared to conven- tional district heating networks (2nd and 65 °C 4th Generation – Low temperature DHC 3rd generation) a high reduction in Operating Temperatures [°C] Temperatures Operating Applicability of Renewables [-] primary energy consumpti- th 25 °C 5 Generation – Cold Heat / Anergy networks on is expected. 1880 1920 1970 2010 2020 – future Development of district heating systems. (in accordance with: Lund, H. et.al.: “The status of 4th generation district heating: Research and results”, 2018) Methods State of the Art in LTDH / Research Project For a detailed evaluation of the various system con- fi gurations and for the investigation of the energetic CDHC & its Limitations DeStoSimKaFe long-term behaviour of the proposed systems the use of simulation tools is indispensable. Using co-simu- Research What’s missing? lation tools, one can utilize different tools especially Most research projects focus on the area of low- • Scientifi cally sound, basic knowledge designed for certain applications, allowing for detailed temperature networks, with few on cold heat. • Methods for the development of holistic system simulations on a component, building and system level. solutions and system optimization Waste heat regeneration • Minimum requirements, areas of application and Scenarios Simulation Framework application limits Heat regeneration from waste water, industrial Models and Tools processes or server facilities • Scientifi c methods for long-term assessment and basic principles for the evaluation of benefi ts Python-Scripts Network design • Business models In CDHC-Systems a special form of the ringshaped Results QGIS-Project DYMOLA topology, the “anergy”-network layout, can be used. Measurements Boundary conditions Demonstration sites Project Goals ADA-System • Munich: waste/cooling water from subway Development of possible system concepts tunnels to supply municipal utilities Framework for the system simulation studies. • Zurich: waste heat from server facilities to feed • Variants for different system confi gurations and a anergy network general conditions For a long-term evaluation of LTDH/CDHC concepts, • Evaluation of possible system solutions for constantly changing system environment conditions Flexibility different confi gurations and boundary conditions need to be taken into account. For this reason, a The current linear topology of district heating grids simulation framework is established, which consi- lacks the required fl exibility when it comes to extending Development of simulation models ders external factors, varying framework conditions and exogenous scenarios like e.g. climate change, the network and implementing decentralized energy • Deterministic modelling approach for technical changes in usage behaviour or renovation rates of sources. evaluation buildings. H • Development of a simulation framework • Evaluation of technical and economic benefi ts SH + DHW G A Development of a stochastic optimisation Heating central HP Electricity Offi ces and commercial Industry Residentials Heat from buildings model concept rooms • Parameter model comprised of fl uctuating (=Cold) B Hydraulic connection C external and internal factors PVT 8°-22°C HP-Cold • Evaluation of optimisation strategies Sewer Cold District HP Heating • Long-term system evaluation Electricity Electricity 8 – 20°C Air ΔT = 4K F E D Development of economic evaluation HP Geothermal methods for LTDH / CDHC Electricity 150m - 300m A E • Business model prototypes and new services Summer Decentralized energy central Groundwater source Waste heat Winter B Connection pipes F Heat recovery from waste water for cold heat Heat pump C Anergy-network (hot and cold side) G Solar collectors Potential layout of a cold district heating network, including several producers. Heat exchanger D Borehole thermal store H Superordinate control system • Economic evaluation Layout of an anergy network (special form of a cold heat network) as proposed by 1 AEE Institute for Sustainable Technologies, Department of Thermal Energy Amstein & Walthert. Technologies and Hybrid Systems, Feldgasse 19, 8200 Gleisdorf, Austria AEE This project is funded by the Klima- und Energiefonds and Institut für Nachhaltige Technologien implemented within the framework of the programme „Energieforschung AS4 2017“. Project number: 865010 Feldgasse 19, 8200 Gleisdorf (A) Energy Research Programme 2017 +43 (0)3112 5886 243 / www.aee-intec.at Runtime: 2 years, [09/2018] to [08/2020].