THERMAL CONTROL ELEMENTS - Laboratory for refrigeration and district energy

Thermag XI 2026: A successful gathering of the solid-state thermal community

admin — Tue, 16 Jun 2026 06:01:05 +0000

The 11th IIR Conference on Solid-State Cooling, Heating and Energy Harvesting – Thermag XI, held from 7-11 June in Ljubljana, Slovenia, has concluded successfully.

This milestone event brought together researchers, engineers, and industry experts from around the world to exchange the latest advances in solid-state cooling, heating, and energy harvesting. Thermag XI provided a unique forum for sharing cutting-edge research on functional materials, emerging concepts, and their integration into next-generation energy systems.

The presentations reflected a wide range of research activities, from fundamental studies and materials development to device prototyping, modelling, and practical applications that contribute to more sustainable energy technologies. The conference proceedings will be published soon on the IIR website: https://iifiir.org/en/conference-proceedings.

We sincerely thank all authors for their submissions and the reviewers for their valuable contributions. Special appreciation goes to the keynote speakers, session chairs, scientific committee, and organizing team whose efforts made the event possible. We also gratefully acknowledge the support of the International Institute of Refrigeration (IIR), the Slovenian Energy Association (SZE), the Chinese Association of Refrigeration (CAR), the Faculty of Mechanical Engineering at the University of Ljubljana, and all sponsors and partners.

The following topics were presented:

THE CONVENTIONAL AND ROTATING MAGNETOCALORIC EFFECT OF A GADOLINIUM PARALLEL PLATE MAGNETIC REGENERATOR – INFLUENCE OF GEOMETRY (Rafael Almeida, Rodrigo Kiefe, Darja Gačnik, Ricardo M. C. Pinto, João O. Silva, Katja Klinar, Henrique Souza, Gonçalo Oliveira, João S. Amaral, Andrej Kitanovski, João H. Belo)

IMPLEMENTATION AND VALIDATION OF AN ACTIVE ELECTROCALORIC REGENERATOR COMPONENT IN TCC BUILDER (Grega Belšak, Izak Oberčkal Pluško, Katja Vozel, Andrej Kitanovski, Markys Cain, Katja Klinar)

NUMERICAL STUDY ON THE FREQUENCY DEPENDENCE OF THE DIRECT MAGNETOCALORIC EFFECT OF GADOLINIUM FILM (Zhonghao Chang, Jorge Revuelta-Losada, Erika Fontana, Nora Dempsey, Katja Klinar, Andrej Kitanovski, Jia Yan Law, Victorino Franco)

VALIDATION OF THE NUMERICAL SIMULATION OF A HIGH-FREQUENCY REGENERATIVE THERMOMAGNETIC GENERATOR HYPEREG (Kamyar Dobakhti, Katja Klinar, Urban Tomc, Jure Javornik, Andrej Kitanovski)

FINITE ELEMENT MODELING AND OPTIMIZATION OF A MAGNETIC FIELD SOURCE FOR THERMOMAGNETIC GENERATION (Radel Gimaev, Katja Klinar, Andrej Kitanovski)

NUMERICAL MODELING OF AN ACTIVE MAGNETIC REGENERATOR BASED ON THE ROTATIONAL MAGNETOCALORIC EFFECT (Radel Gimaev, Darja Gačnika, Urban Tomc, Rafael Almeida, Rodrigo Kiefe, João H. Belo, João S. Amaral, Katja Klinar, Andrej Kitanovski)

PHASE-CHANGE MATERIAL THERMAL DIODES FOR CALORIC REFRIGERATOR (Karl Joulain, Katja Klinar, Katja Vozel, Andrej Kitanovski, Younès Ezzahri)

A GENERALIZED MODELLING APPROACH FOR ACTIVE ELECTROCALORIC REGENERATORS (Matija Kalin, Darja Gačnik, Katja Klinar, Andrej Kitanovski)

HYPEREG: HIGH-FREQUENCY MAGNETOCALORIC REGENERATOR (Andrej Kitanovski, Katja Klinar, Jure Javornik, Simon Nosan, Jakob Perne, Simon Bogić, Blaž Jagodic, Urban Tomc)

THE PERSPECTIVES OF ULTRA-HIGH-TEMPERATURE SOLID-STATE HEAT PUMPS (Katja Klinar, Darja Gačnik, Radel Gimaev, Andrej Kitanovski)

BRIDGING THE THERMAL GAP: THE ROLE OF FLUIDIC AND MECHANICAL THERMAL CONTROL DEVICES IN ADVANCING CALORIC TECHNOLOGIES (Katja Klinar, Urban Tomc, Katja Vozel, Andrej Kitanovski)

THERMAL CONDUCTIVITY OF CELLULOSE-BASED COMPOSITE FILMS (Vanja Kokol, Vera Vivod, Katja Klinar)

MODELING OF THERMOACOUSTIC GENERATOR IN TCCBUILDER (Izak Oberčkal Pluško, Harini Nivetha Raja, Grega Belšak, Jingyuan Xu, Katja Vozel, Andrej Kitanovski, Katja Klinar)

EVALUATION OF CURIE TEMPERATURE EFFECTS IN THE PERFORMANCE OF ACTIVE MAGNETIC REGENERATORS – PART I: SECOND ORDER PHASE TRANSITION (Urban Tomc, Guilherme F. Peixer, Chistian R. H. Bahl, Kaspar K. Nielsen, Jaime A. Lozano, Jader R. Barbosa Jr., Andrej Kitanovski)

DIGITAL MICROFLUIDIC THERMAL SWITCH CAPACITORS FOR MAGNETOCALORIC COOLING (Blaž Velkavrh, Hana Uršič, Urška Erjavec Nagode, Andrej Kitanovski, Lukas Beyer, Jens Freudenberger, Klara Lünser, Enric Stern-Taulats, Lluis Mañosa, Urban Tomc)

ENHANCING SOLID-STATE THERMAL RECTIFICATION VIA TEMPERATURE-DEPENDENT THERMAL CONTACT RESISTANCE (Katja Vozel, Andrej Kitanovski)

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Numerical study of macroscopic thermal diodes: influence of interface topography and contact resistance

admin — Mon, 13 Oct 2025 13:02:34 +0000

We continue our exploration of solid-state thermal diodes – a compact, fully passive asset for next-generation thermal management.

Our latest paper, “Numerical study of macroscopic thermal diodes: influence of interface topography and contact resistance,” has just been published in iScience (IF 4.1).

🔍 Key insights:

Interface topography alone has little effect on the rectification factor when contact resistance is negligible. However, it can extend the temperature range of rectification by up to 10 K.

Constant contact resistance tends to reduce rectification. However, when temperature-dependent contact resistance is introduced at low temperatures, rectification can be boosted significantly. In one case, from nearly zero to nearly unity.

These findings provide new guidelines for optimizing solid-state thermal diodes and open up exciting possibilities for practical thermal management applications.

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FisMat 2025, Venice

admin — Thu, 10 Jul 2025 12:24:59 +0000

At this year’s FisMat conference, held in Venice, Italy, a special workshop on cooling of electronics and sensors took place. As part of the workshop, Katja Klinar gave an invited talk titled “Active and Passive Cooling Methods for Electronics and Sensors.”

The workshop provided an excellent opportunity for an in-depth look at the latest research and innovative solutions in one of the key areas of modern electronics. The high quality of the presentations, the diversity of approaches, and the engaging discussions clearly demonstrated how important and timely this field is.

Sincere thanks to the organizers for a carefully planned and content-rich workshop. It’s always encouraging to see a community so committed to progress—both in scientific understanding and practical application.

More info: https://eventi.cnism.it/fismat2025

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World Refrigeration Day

admin — Thu, 26 Jun 2025 06:19:08 +0000

World Refrigeration Day, celebrated on June 26, was established to raise awareness about the critical role refrigeration, air conditioning, and heat pumps play in modern life. It honors the birth of Lord Kelvin (William Thomson), a key figure in thermodynamics. The day highlights the industry’s contributions to health, food safety, energy efficiency, and environmental protection. Institutions and organizations around the world celebrate it with educational campaigns, public events, webinars, and technical seminars, aiming to inspire innovation and promote sustainable practices in cooling technologies.

TCCbuilder: an open-source tool for the analysis of thermal switches, thermal diodes, thermal regulators, and thermal control circuits

admin — Mon, 11 Nov 2024 07:21:40 +0000

Researchers of the LAHDE laboratory of the Faculty of Mechanical Engineering, University of Ljubljana, have developed an open-source tool for 1D modeling of thermal control circuits, TCCbuilder. It is the first tool of its kind that enables quick and easy modeling of thermal control circuits thanks to its graphical user interface and thr associated library of materials used to create thermal control elements.

In addition to the library of materials, there is also a library of already designed thermal control elements from the literature. Researchers from various fields are invited to complement both libraries as well as to add functionality to the tool. Thus, TCCbuilder is not only an indispensable tool for simulations, but also a platform for the exchange of information and networking of researchers in the field of heat transfer and materials.

The tool is presented in the article TCCbuilder: an open-source tool for the analysis of thermal switches, thermal diodes, thermal regulators, and thermal control circuits, which describes the validation and examples of the use of the tool. The article is published in the journal iScience (IF = 4.6), Special Issue: Advanced thermal control: fundamentals and applications.

The article is freely accessible under the following link: https://doi.org/10.1016/j.isci.2024.111263

Summary:

In the area of thermal management, thermal control elements (TCEs) and thermal control circuits (TCCs) are proving to be innovative solutions to the challenges of temperature control and heat dissipation in various applications, ranging from electronic cooling to energy conversion and temperature control in buildings. Their integration promises to improve power density, energy efficiency, system reliability and system life expectancy. With the aim of connecting researchers in the field of thermal management and accelerating the development of TCEs and TCCs, we have developed an open-source TCC simulation tool called TCCbuilder that enables a quick and easy time-dependent 1D numerical analysis of the behavior of TCEs and TCCs. It uses the heat conduction equation to solve temperature profiles in different devices. The TCCbuilder application offers features not previously available with any other TCC modelling tool: a large adjacent library of materials and TCEs as well as a user-friendly graphical user interface (GUI).

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Calorics 2024, Cambridge

admin — Wed, 25 Sep 2024 10:25:17 +0000

The Calorics 2024 conference took place in the historic city of Cambridge (UK), at the Møller Institute in Churchill College. This event brought together leading experts, researchers, and industry professionals to exchange ideas and insights on the latest advancements in caloric materials and heat-pump technologies.

The presentations highlighted the recent development in magnetocaloric, electrocaloric, elastocaloric, and barocaloric materials, as well as their potential integration in (multi)caloric devices such as heat pumps and active regenerators.

The LAHDE’s contribution to the conference was Prof. Andrej Kitanovski’s presentation: »Challenges, opportunities, and future roadmap for energy applications of magnetocaloric materials«.

One of the standout moments of the conference was the demonstration of a refrigerator utilizing the barocaloric effect to efficiently pump heat, presented by Xavier Moya. Its cooling power was impressive enough to chill beers to the perfect temperature, which were then served to attendees after the presentations. We cannot wait for the day when we can have solid-state refrigerators in our own homes.

Attending the Calorics 2024 conference was an exceptional experience, offering invaluable opportunities for learning and collaboration, encompassed by the engaging discussions with fellow attendees. The wide range of presentation topics provided deep insights into the latest caloric materials and technologies.

We are excited to attend and present our research at the upcoming Calorics conference. We can’t wait to see how the field will develop in the future.

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SDEWES 2024

admin — Mon, 16 Sep 2024 05:20:19 +0000

The SDEWES 2024 conference in Rome was a truly remarkable event, bringing together leaders, researchers, and professionals dedicated to advancing sustainable development and energy systems. As one of the premier conferences in this field, SDEWES provided a unique platform for exchanging cutting-edge ideas and fostering collaborations that can drive global change.

Throughout the conference, a wide range of topics were covered, from renewable energy integration and smart grids to circular economy principles and sustainable urban planning. The diversity of perspectives and the depth of the discussions were nothing short of inspiring. It was clear that the collective expertise and passion of the attendees are key to addressing the complex challenges we face in creating a more sustainable future.

The LAHDE’s contribution to the conference was a presentation by Katja Klinar, who shared insights on “Heat Pump Modelling in District Heating and Cooling Grid.” This work is a crucial part of the SenergyNets project, which is paving the way for more efficient and sustainable energy systems.

Attending SDEWES 2024 was a powerful reminder of the importance of collaboration across disciplines and borders. The ideas and connections forged here will undoubtedly have a lasting impact on the future of sustainable energy and development.

Looking forward to continuing the journey with this incredible community and applying the insights gained from this experience.

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TCCbuilder WS: we discovered the possibilities of modeling thermal circuits

admin — Mon, 16 Sep 2024 04:28:31 +0000

On Thursday, September 5, we held an online workshop where we learned about the functionality of the open source tool for modeling thermal control elements and thermal circuits, TCCbuilder.

We discovered the possibilities of modeling thermal control circuits in various fields of application, which stimulated the discussion of the workshop participants – researchers from different parts of the world – in the direction of further development of the tool.

We would like to thank all the participants for their participation in the workshop and invite them to further collaborate on the project.

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LAHDE Team Attends Thermag 2024 and Visits the World’s Largest Rare Earth Manufacturing Hub

admin — Tue, 27 Aug 2024 09:42:30 +0000

The LAHDE team recently had the privilege of attending the 10th IIR Conference on Caloric Cooling and Applications of Caloric Materials (THERMAG 2024) in Baotou, China. This event was particularly memorable as it also provided our team the opportunity to visit Baotou, the world’s largest hub for rare earth production. Baotou’s industry is a cornerstone for the production and manufacturing of materials used in numerous advanced applications.

Our visit to the Baotou Research Institute of Rare Earths was an invaluable experience, offering us insights into the city’s pivotal role in the global rare earth industry. This visit aligned perfectly with our participation in THERMAG 2024, where we engaged with the latest advancements in caloric materials, prototypes, and their potential applications.

At the conference, the LAHDE team presented a diverse range of contributions, highlighting our cutting-edge work in the magnetocaloric field, including:

Prof. Dr. Andrej Kitanovski: Solid-State Energy Conversion: Applications and Perspectives (plenary talk)
Dr. Urban Tomc (Nada Petelin): Oscillating Gadolinium Thermal Switch
Assist. Prof. Dr. Katja Klinar: Navigating the Heat Maze: A Showcase Tutorial of TCCBuilder Software
Dr. Urban Tomc: High Frequency Magnetocaloric Cooling

We were thrilled to share our ideas and experiences with esteemed colleagues, scientists, and engineers from both academia and industry. The exchange of knowledge and the potential for future collaborations were among the many highlights of this event.

On a side note, we also took the opportunity to explore other wonders of China, such as the historic sites of Beijing and even climbed a section of the Great Wall.

We are also deeply honored to announce that LAHDE will be the host organizer for the next, 11th THERMAG conference in 2026, which will take place in Ljubljana, the beautiful capital of Slovenia. We look forward to welcoming you all!

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TCCbuilder workshop

admin — Wed, 14 Aug 2024 12:35:52 +0000

The Laboratory for Refrigeration and District Energy (LAHDE) invites all students, researchers and other interested parties to a free online workshop, where you will have the opportunity to learn about the world’s first open source tool for thermal control circuits – TCCbuilder.

When? Thursday, September 5, 2024, at 2:00 p.m CEST.
More information and registration: https://tccbuilder.org/

You can apply until September 1 via the link above. Registration is required.

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