Distributed Cold Storages in District Cooling

Funded by: Swedish Energy Agency
Time period: 2018-04-01 – 2021-03-31
Project partners: KTH, Norrenergi AB, Energiforsk

Background

The project “Distributed Cold Storages in District Cooling” is a work package (WP 2.3) in the program “Thermal energy storage- the solution for a flexible energy system”  coordinated by Energiforsk.

District cooling (DC) is an efficient end environmental friendly way of providing cooling particularly for densely populated regions or close-neighborhoods. To lower the installation costs of a DC system yet still to cover the peak cooling demands, cold storage is sought for. Despite experiencing a northern climate, Sweden also has a considerable cooling demand throughout the year, particularly from industrial, service and commercial sectors. Besides, with climate change now a reality, these cooling demands are on the rise, while residential cooling in summer may also come as a demand eventually. In this context, Swedish DC systems are anticipating cooling supply expansions and here cost-effectiveness is the key, where cold storages could play a deterministic role.

Aim and objectives

In this context, the aim of this project is to map the current context of DC and cold storage in Sweden, and by means of a case study system (namely of Norrenergi AB’s DC system), investigate the opportunities in cold storage, particularly at distributed locations, to cost-effectively expand the cold supplies. To achieve this, the objectives are:

• map the current context of distributed and centralized cold storage in DC in Sweden
• conduct a techno-economic performance evaluation on the chosen case study (Norrenergi AB’s DC) system, for both distributed and centralized cold storage alternatives and their operational strategies optimization
• thereby, conduct a cost-benefits analysis of the analyzed cold storage alternatives, concerning both the DC and energy system as a whole.
• thereby also conduct a total costs comparison of the chosen cold storage alternative with other typical cooling capacity increasing means
• Evaluation or comparison of optimal operating strategies for alternative cold storages (e.g. cold water accumulator tanks, phase change materials, and underground storages) with regard to technical and economic performance and impact on operation
• Present key specific as well as general conclusions as related to DC supply optimization and extension and the role of cold storage in that

Outcomes

• Successful progress presentation at all the bi-annual progress workshops organized by Energiforsk
• The completion of 02 master’s thesis projects with final reports published open access in KTH DiVA
• The completion of 01 master’s level student project and report (MJ 2409 Applied Energy Technology, Project Course, 9.0 credits in 2018)
• 03 conference publications with oral presentation of the results ( Eurotherm Seminar n°112- 2018 , Enerstock 2021  and DHC2021 )
• A final report on WP 2.3  published with open access in Energiforsk web
• Fruitful collaboration on a peripheral work package 2.1 (Techno-economic comparison between different techniques for thermal storage in regional energy systems) with contributions into its final report  published with open access in Energiforsk web
• International collaboration and dissemination of the project results at the IEA ECES Annex 35 (now Task 35) on Flexible Sector Coupling
• A final journal publication (being written)

Publications

1. Y. W. Biramo, "Optimization of Distributed Cooling and Cold Storage in Sweden:," KTH Royal Institute of Technology, Stockholm, 2019. Master’s thesis report. TRITA-ITM-EX 2019:712. At KTH DiVA.
2. Z. Bilek, "Performance assessment in district cooling networks using distributed cold storages – A case study," KTH Royal Institute of Technology, Stockholm, 2020. Master’s thesis report. TRITA-ITM-EX 2020:252. At KTH DiVA.
3. Pablo Mayo, Faisal Sedeqi and Miguel Tavares, 2018. “Analysis of Distributed Colling and Cold Storage in Sweden”. Project final report, group 37 at MJ 2409 Applied Energy Technology, Project Course (9.0 ECTS). KTH Royal Institute of Technology, Stockholm, 2018.
4. J. Holgersson, O. Räftegård, S. N. Gunasekara och R. Scharff, ”Teknoekonomisk jämförelse av olika tekniker för termiska lager i fjärrvärmenät”. Energiforsk, Stockholm, 2019. ISBN 978-91-7673-598-5.
5. S. N. Gunasekara, V. Martin, T. Edén, F. Sedeqi, M. Tavares and P. S. Mayo Nardone, "Distributed cold storages for district cooling in Sweden- The current context and opportunities for the cold supply expansion," in Eurotherm Seminar #112- Advances in Thermal Energy Storage, Lleida, 2018.
6. S. N. Gunasekara, Y. W. Biramo and T. Edén, "District cooling system optimization with distributed cold storage adopting power-to-cold: A case study on Norrenergi AB," in Enerstock 2021, Ljubljana, 2021.
7. S. N. Gunasekara, Z. Bilek, T. Edén and V. Martin, 2021. ” Distributed cold storage in district cooling – grid dynamics and optimal integration for a Swedish case study”. At the 17th International Symposium on District Heating and Cooling (DHC 2021), 06-09 September 2021, Nottingham, UK.
8. S. N. Gunasekara, V. Martin and T. Edén, "Distributed Cold Storage in District Cooling (Distribuerade Kyllager i Fjärrkylanät)," Energiforsk, Stockholm, 2021. ISBN 978-91-7673-751-4.

Project contact persons:

PhD, Researcher, KTH, Project WP 2.3 researcher

Head of the Division of Energy Systems (KTH), Project WP 2.3 leader

Mr. Ted Edén , Energy System Developer, Norrenergi AB, Project WP 2.3 company collaborator and contact