STOCKHOLM, 18 June 2026 — Researchers from the Horizon Europe-funded I-UPS project are developing a compact heat exchanger designed to support the integration of hightemperature heat pumps and thermal energy storage systems for industrial applications.
The design, led by KTH Royal Institute of Technology (KTH) in collaboration with Wroclaw University of Science and Technology, addresses a key technical challenge in industrial electrification, which is transferring heat efficiently between pressurized working gases and molten salt thermal energy storage, under demanding high-temperature operating conditions.
The heat exchanger forms part of the I-UPS project, which is developing and validating a hightemperature heat pump system capable of delivering industrial heat up to 400°C while integrating renewable electricity, waste heat recovery and thermal energy storage
Within the project, researchers are investigating a compact, baffle-less shell-and-tube heat exchanger concept designed to improve heat transfer while limiting pressure losses.
Traditional shell-and-tube heat exchangers typically use internal baffles to direct fluid flow and increase thermal contact. The I-UPS design explores alternative geometries that promote fluid mixing and heat transfer without relying on conventional baffle arrangements.
The objective is to increase heat transfer effectiveness while supporting compact system integration, high-temperature operation, drainability and overall system efficiency. Funded by Horizon Europe Grant Agreement No. 101147078.
"The heat exchanger is a key interface between the Stirling heat pump cycle and the molten salt thermal energy storage system," said Parth Kumavat, post-doc researcher at KTH. "Our objective is to develop a design that supports efficient thermal integration while maintaining the operational flexibility required for industrial applications."
A distinctive aspect of the research is the combination of numerical optimization and additive manufacturing. Researchers at KTH are using genetic algorithms to evaluate and optimise heat exchanger geometries, balancing thermal performance against pressure-drop penalties.
The resulting designs will then be additively manufactured from 316L stainless steel using the Laser Powder Bed Fusion of metals (PBF-LB/M) technique and tested by the Department of Advanced Manufacturing Technologies at Wroclaw University of Science and Technology.
This approach enables the production of complex internal geometries that are difficult to manufacture using conventional fabrication techniques, and reduces the effort of joining operations during fabrication.
"Additive manufacturing enables the production, and evaluation of complex geometries, the consolidation of assemblies into single components, and the processing of high-temperature materials, all of which would be impractical using traditional manufacturing methods," said Andrzej Pawlak, Deputy Head of Department, Faculty of Mechanical Engineering, Advanced Manufacturing Technologies, Wroclaw University of Science and Technology. "By combining advanced design optimisation with metal 3D printing, we can investigate new he
The heat exchanger is being developed to operate alongside Enerin's Stirling-based hightemperature heat pump technology and Kyoto Group's molten salt thermal energy storage solution.
The compact heat exchanger would support the e]icient heat delivery without relying on GlobalWarming Potential refrigerants, while maintaining high e]iciency across a wide temperature range and integrating seamlessly with waste heat and renewable energy sources.
The research collaboration forms part of the project's progression towards TRL 5 validation, supporting the development of industrial heat pump solutions for sectors such as chemicals, food processing, pulp and paper, and other energy-intensive industries.
Co-ordinator: Communication:
Silvia Trevisan (trevisan@kth.se) Philippa Webb Muegge
KTH Royal Institute of Technology Enerin AS (philippa@enerin.no)
Department of Energy Technology,
Division of Heat and Power Technology