refrigeration - Laboratory for refrigeration and district energy

Phase change materials for more efficient household refrigeration

admin — Tue, 18 Aug 2026 08:27:13 +0000

A new review paper, Phase Change Materials for Performance Enhancement in Household Refrigeration: A Review, has been published in Strojniški vestnik – Journal of Mechanical Engineering. The paper explores the use of phase change materials (PCMs) to improve the performance of household refrigeration systems.

PCMs can store and release thermal energy during a phase transition, thereby increasing the thermal inertia of a refrigeration system. When properly selected and integrated, they can contribute to more stable temperatures, improved system efficiency, reduced peak loads, and longer preservation of suitable temperatures during power outages.

The paper presents key criteria for PCM selection and reviews different integration strategies, including PCM placement at the evaporator, condenser, inside the refrigerated compartment, and in combined configurations. The review also shows that commercially available PCMs already cover temperature ranges relevant to household refrigeration. Achieving the desired benefits, however, strongly depends on selecting an appropriate phase-change temperature and integrating the material correctly into the refrigeration system.

The work was carried out within the GreenTech project and is the result of collaboration between researchers from the Faculty of Mechanical Engineering, University of Ljubljana, and Gorenje, Hisense Europe.

The paper was authored by Urban Tomc, Katja Klinar, Luka Porenta, Marko Kralj, Tomaž Bregar and Andrej Kitanovski.

Paper: Phase Change Materials for Performance Enhancement in Household Refrigeration: A Review
DOI: 10.5545/sv-jme.2026.1670

The post Phase change materials for more efficient household refrigeration first appeared on Laboratory for refrigeration and district energy.

Comprehensive thermodynamic screening of low-GWP refrigerant mixtures for micro-scale vapour compression refrigerators and heat pumps

admin — Tue, 14 Jul 2026 18:19:52 +0000

As the demand for high-performance micro and power electronics grows, micro-scale vapour compression refrigeration (VCR) systems and heat pumps (VCHP) have emerged as critical technologies for active heating and cooling. However, the progressive phase-down of hydrofluorocarbon refrigerants under international environmental regulations, necessitates the identification of low-global warming potential alternatives specifically optimized for the unique constraints of small-scale hardware, such as limited compressor displacement and low refrigerant charge.

This study presents a comprehensive and systematic thermodynamic screening of approximately 30,000 refrigerant compositions, including pure fluids, binary, and ternary mixtures, specifically aimed at three key application scenarios: domestic and commercial micro-appliances, personal cooling systems for hostile environments, and reversible heat pumps for electric vehicle cabin and battery management. Using a multi-criteria decision-making approach based on the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method to maximize simultaneously coefficient of performance and volumetric heating and cooling capacity, optimal candidates were identified across four practical scenarios: high-performance, safety-critical – low-flammability (A1), low-pressure, and a combined low-pressure/non-flammable scenario.

Findings demonstrate that added complexity in ternary mixtures offer no significant thermodynamic advantage over simpler binary blends for micro-scale applications. Final recommendations for next-generation micro-VCR/VCHP systems include: R1270 and R290/RE170 (60/40)% for maximum performance; R1234yf/R1224yd(Z) (72/28)% for safety-critical (A1) applications; RE170/R600 (65/35)% and R600/R1270 (28/72)% for natural, low-pressure operation; and R1234ze(E)/R1233zd(E) (72/28)% or R1234ze(E)/R1224yd(Z) (68/32)% for combined constraints. This study establishes a structured roadmap to navigate the complex landscape of sustainable refrigerant selection in the micro-VCR/VCHP domain.

Link: https://doi.org/10.1016/j.applthermaleng.2026.132282

The post Comprehensive thermodynamic screening of low-GWP refrigerant mixtures for micro-scale vapour compression refrigerators and heat pumps first appeared on Laboratory for refrigeration and district energy.

Ultra-high-temperature electrocaloric heat pump

admin — Mon, 05 Jan 2026 09:01:01 +0000

Researchers from the Laboratory for Refrigeration and District Energy (LAHDE) have published first study on high-temperature electrocaloric heat pump in Journal of Energy conversion and management, one of the world’s leading scientific journal in the field of energy.

Nearly a quarter of waste heat is generated at temperatures exceeding 300 °C, yet conventional heat pump technologies remain inefficient in recovering and utilizing heat from such high temperature sources. In this study, we introduce a novel electrocaloric heat pump designed to operate with heat sources and sinks at ultra-high temperatures. The proposed heat pump system incorporates an active electrocaloric regenerator featuring PbZr_0.52Ti_0.48O₃ (PZT) epitaxial thin-film multilayers, which exhibit a superior electrocaloric adiabatic temperature change of 11.03 K at 402 °C (675 K), and pressurized helium gas as the working fluid. We conducted a parametric analysis to simulate the performance of the ultra-high-temperature electrocaloric heat pump and identified the optimal conditions for single- and multi-stage configurations. The single-stage setup achieved a maximum heating COP of 7.8 at a 30 K temperature span across the regenerator at a heat source temperature of 660 K. In comparison, the multi-stage configuration yielded the highest heating power 113.3 W/kg_EC and a max. COP 2.7 between 630 and 690 K. This study established a foundation for notable advancements in ultra-high-temperature heat pumps by employing electrocaloric energy conversion.

Link: https://www.sciencedirect.com/science/article/pii/S019689042501338X

The post Ultra-high-temperature electrocaloric heat pump first appeared on Laboratory for refrigeration and district energy.

Emerging opportunities for high-temperature solid-state and gas-cycle heat pumps

admin — Sun, 21 Dec 2025 12:51:38 +0000

Researchers from the Laboratory for Refrigeration and District Energy (LAHDE), together with an international team, have published a study in Nature Energy (Springer Nature), the world’s leading scientific journal in the field of energy. The paper offers the first comprehensive assessment of an often-overlooked opportunity: alternative high-temperature heat-pump technologies that could replace inefficient fossil-fuel combustion and direct electric heating in industry and the energy sector. Doing so could significantly reduce energy use, greenhouse-gas emissions, and thermal pollution.

Heat lies at the core of the energy challenge. Around 50% of final energy consumption is used for heating and cooling, and roughly 50% of final energy is ultimately released as waste heat—heat that is frequently discharged into the environment via cooling towers, the warming of rivers or seawater, and other outlets. The study shows that high-temperature heat pumps can capture this waste heat and upgrade it efficiently to much higher temperature levels, suitable for demanding industrial processes.

Today’s commercial high-temperature heat pumps are typically limited to about 250 °C, whereas many industrial processes require higher temperatures—up to, or even beyond, 1000 °C. The newly published research therefore systematically presents and compares alternative approaches that could enable a step change: caloric, thermoelectric and thermoacoustic technologies, as well as mechanical processes based on Stirling and Brayton cycles.

Link: https://www.nature.com/articles/s41560-025-01908-4

The post Emerging opportunities for high-temperature solid-state and gas-cycle heat pumps first appeared on Laboratory for refrigeration and district energy.

MAGCCINE – 1st annual meeting in Grenoble

admin — Thu, 23 Oct 2025 13:19:37 +0000

The first annual meeting of the MAGCCINE consortium took place on 17 October 2025 in Grenoble. The event was hosted by the Institut Néel (CNRS), which, together with MagREEsource, provided excellent organization and a warm welcome to all participants.

The meeting offered an exceptional opportunity for project partners to present the achievements of the first year of collaboration, exchange ideas, and outline the next steps in the development of a vaccine cooler prototype based on the rotating magnetocaloric effect. At the heart of the event was collaboration: exchanging ideas, reviewing progress, and planning future activities between academic and industrial partners. The discussions were enriched by in-depth scientific exchanges on cooling, magnetism, and related innovations.

The meeting was further enhanced by contributions from Advisory Board members, including representatives of the International Institute of Refrigeration (IIR) and Tecnea – Cemafroid, who provided valuable insights into key issues related to innovation and standardisation in the field of cooling technologies.

The programme also included a visit to MagREEsource, a company specialising in sustainable development and the recycling of used magnets. Their production capacities, scientific approach to designing the entire recycling value chain, and their clear sustainability vision left a strong impression on all participants.

The first annual MAGCCINE consortium meeting inspired everyone involved and strengthened the shared sense of responsibility for further developing technologies with the potential to significantly contribute to more sustainable solutions for global cold chains.

The post MAGCCINE – 1st annual meeting in Grenoble first appeared on Laboratory for refrigeration and district energy.

SDEWES Conference 2025 Dubrovnik, Croatia

admin — Fri, 10 Oct 2025 13:56:23 +0000

The 20th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) in Dubrovnik hosted 685 on-site and 115 online participants from 68 countries presented 839 papers, showcasing an impressive range of recent research on sustainable energy, water, and environmental systems.

Our team had the pleasure of presenting on the final day (when many were already running low on energy), yet we were happy to still see engaged researchers in the audience.

Assist. Prof. Katja Klinar presented part of the modeling activities related to the pandaprosumer tool. The title of presentation was: pandaprosumer: Modeling the integration of booster heat pumps and combined heat & power systems into a district heating network.

This work presented was done within the SENERGY NETS project, funded by the European Union 🇪🇺.

A big thank-you to the organizers for such a well-run and inspiring event, and to everyone contributing to the dialogue on a more sustainable energy future!

More information: https://www.dubrovnik2025.sdewes.org/index

The post SDEWES Conference 2025 Dubrovnik, Croatia first appeared on Laboratory for refrigeration and district energy.

World Ice-Cream Day

admin — Fri, 18 Jul 2025 14:04:42 +0000

🍦Happy World Ice Cream Day!🍦 Did you know this celebration, held on the third Sunday of July, was established in 1984 by U.S. President Ronald Reagan to honor the joy ice cream brings? But ice cream’s story goes back much further, and it wasn’t always so accessible.

Centuries ago, ice cream was a luxury reserved for the wealthy and powerful. Before modern refrigeration, making ice cream required natural ice harvested in winter, stored in ice houses, and combined with salt to lower the freezing point. This was a time-consuming, costly process. This meant the treat was typically served only at royal banquets and elite gatherings. It wasn’t until the 20th century, with refrigeration and mass production, that ice cream became the beloved dessert we all enjoy today.

Beyond its sweet taste, ice cream is a fascinating blend of science and engineering. It’s a multiphase system of air bubbles, partially coalesced fat globules, ice crystals, and an aqueous phase containing sugars, salts, and proteins. Texture depends heavily on ice crystal size, which ties into a principle called the Kelvin effect: smaller crystals freeze at slightly lower temperatures than larger ones due to their higher surface energy. This is why constant churning and rapid freezing are essential for that smooth, creamy mouthfeel.

Ice cream production, however, isn’t just about flavor. It has an environmental footprint. Producing one liter of ice cream consumes 0.5–1.5 kWh of energy and emits 1.5–3.5 kg of CO₂-equivalent, largely from dairy farming and processing. Up to 30% of input energy is lost as heat during freezing and mixing, and air incorporation ranges from 20% to 100% (premium varieties hover around 50%). Improving energy efficiency in these thermo-fluid processes could cut the carbon footprint by 10–25%, making the industry more sustainable.

And if you’re wondering about the fastest way to make ice cream? Just add liquid nitrogen (at -196°C) for an instant freeze and ultra-smooth texture!

So today, as you indulge, remember: every scoop is a perfect blend of history, physics, and a sprinkle of sustainability. ❄️🔬🍨

The post World Ice-Cream Day first appeared on Laboratory for refrigeration and district energy.

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

The post FisMat 2025, Venice first appeared on Laboratory for refrigeration and district energy.

Conference SZE 2025, Portorož

admin — Fri, 27 Jun 2025 14:05:10 +0000

Between 8th and 10th of June international conference SZE 2025 took place in Portorož. Main topics of this year’s meeting were regional transformations of energy systems. Talks focused on energy and economical efficiency, digitalization of energy systems, renewable energy sources, heating and cooling technologies, district energy systems, heat pumps etc.

LAHDE team presented the following topics:

Andrej Kitanovski: 50% / 50% / 50%: UNTAPPED POTENTIALS AND OPPORTUNITIES FOR HEATING AND COOLING
Nada Petelin: ENHANCING THE PERFORMANCE OF HOUSEHOLD REFRIGERATORS WITH PHASE CHANGE MATERIALS
Izak Oberčkal Pluško: MODELING HEAT PUMPS WITH THERMAL STORAGE IN DISTRICT HEATING SYSTEMS

Besides members of LAHDE, Marko Keber from University of Ljubljana, Faculty of Mechanical Engineering also presented his topic:

Marko Keber: MODELING OF DISTRICT ENERGY NETWORKS WITH MINIMAL DATA

Conference was an excellent opportunity for exchanging ideas, listening to exceptional speakers and connecting with with researchers and industry experts.

More informations on conference can be found here: https://www.sze.si/en/about-the-conferences-2025/

The post Conference SZE 2025, Portorož first appeared on Laboratory for refrigeration and district energy.

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.