Va-Q-tec founders welcome takeover offer

Joachim KUHNEQT Private Equity of Sweden, supported by co-investors Mubadala and Cinven, announced a voluntary public takeover offer this month to shareholders of va-Q-tec at an offer price of 26 euros per share. Va-Q-tec’s founding families will retain a significant stake “to ensure further operational and strategic development in accordance with the intentions of va-Q-tec’s founders.”

In a LinkedIn post, va-Q-tec CEO Joachim Kuhn said: “As a founder and shareholder, myself and the founders families support and welcome the EQT partnership offer. We have a strong partner in EQT and this will enable us to continue creating a world-scale innovator in many fields.”

Completion of the takeover offer, subject to regulatory clearances, is expected to occur by the second quarter of 2023.


• The RAL Quality Association PCM has launched a searchable database of member products. The database includes more than 160 PCMs with phase transition temperatures ranging from -65° C to 111° C. The intention is to allow website visitors to find a PCM that may be suitable for the application they have in mind. So far, six member companies – va-Q-tec AG, RuhrTech, Pluss Advanced Technologies, Rubitherm Technologies, ISU Chemical and Sasol Germany – have contributed product listings.

Rubitherm Technologies is reporting “significant results” in testing of PhaseTube, the Berlin company’s water-based PCM heating and cooling product. “For small temperature ranges the PhaseTube shows 3 to 4 times higher storage density than water and around 2 times more than a commercial reference product in the market,” the company said in a LinkedIn post. More information on the product is available on Rubitherm’s website,

Lukas BERGMANN• “We need to talk about dunkelflaute,” writes Lukas Bergmann, head of product management at Sunamp Ltd. Sehr interessant! Aber was ist dunkelflaute? It’s a German word – “dark lull” – coined to describe periods in which little or no renewable energy can be generated with wind and solar power. In a blog post, Bergmann explains how higher-capacity heat batteries combined with heat pumps can bridge the gap.

• In an effort to prevent rolling power cuts, UK’s National Grid has significantly increased its financial incentive for households to shift power use away from peak times. “Its electricity system operator (ESO) has increased the incentive sixfold to £3 per kilowatt hour (kWh) to encourage households to use their washing machines and appliances late at night, which could mean typical savings of £100 this winter,” the Guardian reports. Harald Mehling posted a link to the article in the Phase Change Matters group on LinkedIn. He writes: “If using electricity for heating, by direct electric heating or via a heat pump, heat storage could allow users to leave their heating demand unchanged with regard to time, while fitting their electricity demand to the most economic times. It will be interesting to see how electricity bills change for those already using some kind of heat storage.”

Andreas Hauer, chairman of the board at the Bavarian Center for Applied Energy Research (ZAE Bayern) has joined the steering committee of the energy storage working group at the European Commission’s Investors Dialogue on Energy. IDE brings together experts from energy and finance sectors in all EU countries “to assess and upgrade financing schemes to mobilise financing in the context of the European Green Deal.”

Evelyn N. Wang has been confirmed as director of the Advanced Research Projects Agency-Energy at the U.S. Department of Energy. Wang is the head of the mechanical engineering department at the Massachusetts Institute of Technology. She is noted for her research in phase-change heat transfer in electronics, thermal batteries, solar thermal energy conversion and desalination devices.

Enerstock Online 2023 is set for Feb. 14-15. The free online conference will focus on research and policy developments in energy storage. Speakers will include Lars Stephan of Fluence GmbH, Germany; Mary Ann White of Dalhousie University, Canada; and Changwon Suh, U.S. Department of Energy.


Green energy thermal storage system

U.S. patent application 20220404104 (applicant Holtec International, Camden, N.J.):

Holtec patent drawing

“A thermal energy storage system includes one or more containment vessel comprising an internal cavity containing a bed of phase change material (PCM) operable to store thermal energy, an array of heaters embedded in the molten phase change material, and a tube bundle. The heaters are electrically coupled to an electric power source and operable to heat and melt the PCM to a molten state. The tube bundle comprises heat exchanger tubes embedded in the molten PCM and configured to convey a working fluid (e.g., water or other) through a tube-side of the tubes. The tubes may be arranged in plural individual tube cartridge each insertable and removable from the vessel. In operation, the working fluid is heated by absorbing stored thermal energy from the molten phase change material. The PCM may be heated by power extracted from the power grid during off-peak demand periods.”

Thermal heat exchange cascade

U.S. patent application 20220401852 (applicant Energy Innovation Systems Ltd., Hong Kong):

“A system to extract water from the environment and control temperature through heat transfer between two or more environments, with low energy consumption, for domestic, commercial, or industrial use, which comprises: at least one force unit (10), capable of increasing or decreasing the pressure of the thermal working fluid, wherein the force unit (10) comprises one cylinder (1), which comprises within at least one plunger (2) joined to a piston (27), wherein the piston (27) moves alternately through the is activation of a directional control valve (29) that receives hydraulic fluid from a hydraulic pump (32); at least one closed chamber connected to the cylinder (1), wherein that closed chamber comprises at least one tube (12) joined with at least one closed radiator (8a, 8b) wherein thermal working fluid is compressed inside that closed chamber, wherein the change from liquid to solid state or vice versa occurs, or from solid to another solid state or vice versa; and a control unit (11) that regulates the operation of the directional control valve (29) according to the temperature and pressure obtained from the closed chamber.”

Multisource heat exchange system

U.S. patent application 20220400625 (applicant Ceres Greenhouse Solutions LLC, Boulder, Colorado):

Ceres patent drawing

“A multi-source ground-to-air heat transfer system is configured to store thermal energy during a cooling/dehumidifcation mode of operation for future use during a heating mode of operation. The multi-source ground-to-air heat transfer system utilizes a ground loop that is configured under an enclosure, such as a greenhouse, and is in thermal communication with a thermal reservoir medium to conduct and store heat. A thermal exchange fluid is pumped through the ground loop and ground heat exchanger and may receive heat from a condenser during a cooling/dehumidification mode of operation and may liberate heat to the evaporator during a heating mode. … The north wall of an exemplary greenhouse may comprise a phase change material that absorbs heat during the daylight hours and then emits heat into the greenhouse during the night to moderate the temperature of the greenhouse.”

Energy storage system

U.S. patent application 20220390186 (applicant Sunamp Ltd., Great Britain):

“There is herein described energy storage systems. More particularly, there is herein described thermal energy storage systems and use of energy storable material such as phase change material in the provision of heating and/or cooling systems in, for example, domestic dwellings.”

More U.S. patent applications:

Infant bottle system (Ember Technologies Inc., Westlake Village, California) | Composite construction panels (Phase Change Solutions Inc., Asheboro, N.C.) | Vacuum insulated container (Oyster Thermal AS, Oslo, Norway) | High efficient central chiller plant system (Boca International Ltd., Hong Kong) | Microcapsules for low-temperature well cementation (Southwest Petroleum University, Chengdu City, China) | Method and apparatus for heat storage (Graphite Energy Pty. Ltd., Surry Hills, Australia.) | Constant temperature container (Panasonic Intellectual Property Management Co. Ltd., Osaka, Japan) | Building insulation (South China University of Technology, Guangzhou, China) | Heat exchange using phase change material (Lockheed Martin Corp., Bethesda, Maryland) | Surgical cap to control patient body temperature (Equalizer Technology LLC, Rocky River, Ohio)


From Journal of Energy Storage:

Thermal energy storage co-benefits in building applications transferred from a renewable energy perspective
Form-stable flexible composite multi-phase change material with high latent heat and enhanced thermal conductivity for thermal management
A characteristic-oriented strategy for ranking and near-optimal selection of phase change materials for thermal energy storage in building applications
Outline of the incorporation of phase change materials in radiant systems
Shape-stabilized phase change material for thermal energy storage: Sr+2 doped BaCO3 matrix incorporating polyethylene glycol

From Journal of Polymer Research:

A review on the micro-encapsulation of phase change materials: classification, study of synthesis technique and their applications

From Materials Chemistry and Physics:

n-Eicosane-Impregnated nonwoven phase change mats of electrospun Poly(ethylene oxide)/Poly(methyl methacrylate) blended fibers

From Energy:

Energy and environmental performance of photovoltaic cooling using phase change materials under the Mediterranean climate
Model-driven development of durable and scalable thermal energy storage materials for buildings
A novel cascade latent heat thermal energy storage system consisting of erythritol and paraffin wax for deep recovery of medium-temperature industrial waste heat

From Construction and Building materials:

Low-cost phase change materials based concrete for reducing deicing needs

From Applied Thermal Engineering:

Parametric study of low-temperature thermal energy storage using carbon dioxide as the phase change material in pillow plate heat exchangers

From Case Studies in Construction Materials:

Comparative analysis of form-stable phase change material integrated concrete panels for building envelopes

From Journal of Phase Change Materials:

Inorganic salt hydrates-hydrogel composites as phase change materials for energy storage in buildings

From Wiley Interdisciplinary Reviews:

A review of phase change materials and heat enhancement methodologies

From Renewable Energy:

Effectiveness assessment of different kinds/configurations of phase-change materials (PCM) for improving the thermal performance of lightweight building walls in summer and winter

From Applied Energy:

Cyclic performance characterization of a high-temperature thermal energy storage system packed with rock/slag pebbles granules combined with encapsulated phase change materials

From ACS Sustainable Chemistry & Engineerin:

Flexible and Biocompatible Silk Fiber-Based Composite Phase Change Material for Personal Thermal Management

Happy new year to you!

And many thanks to all Phase Change Matters subscribers who made the newsletter a part of their monthly routine in 2022. Like what you’ve seen? Please invite a friend or colleague to subscribe.

Here are the most-clicked links of the past 12 months:

1. Nostromo Energy installing IceBrick systems in Israeli hospital, Beverly Hills hotel [June]

2. China-based startup Passive Edge Tec is finalist in the CapitaLand Sustainability X Challenge 2022 [July]

3. Registration is open until Oct. 14 for IMPRES 2022, the Sixth International Symposium on Innovative Materials and Processes in Energy Systems [September]

4. PCMs: A mature technology with a wide range of uses [March]

5. Azelio AB installing a long-duration TES system at a convenience store in Fresno, Calif. [June]

6. MGA Thermal, manufacturer of miscibility gap alloys, unveils first stage of commercial facility in Newcastle, Australia [July]

7. Green Building Advisor’s PCM product guide [October]

8. How did Sunamp get its start? [August]

9. InnoCap of China is looking to liquidate its inventory of Inno C16 [August]

10. Rubitherm unveils new HVAC product, PhaseDrum [May]

The most-clicked U.S. patent applications:

Thermal storage materials and applications (Brandeis University, Waltham, Mass.) [July]

Switchable PCM systems for building envelopes (University of Colorado, Denver) [April]

The most-clicked research paper:

Salt hydrate phase change materials: Current state of art and the road ahead (Journal of Energy Storage) [March]


Connect with PCM experts and industry leaders on LinkedIn

LinkedIn logoMore than 1,750 people have joined a LinkedIn group devoted to the discussion of phase change material and thermal energy storage. You are invited to join the Phase Change Matters group and connect with PCM and TES experts from around the world.

This month we welcome João Pato, client executive at GWA Supplies Ltd., Porto, Portugal; Jaime Guzman, plant manager at Viking Cold Solutions Inc., Houston, Texas; Mahdi Jafaripour, lab technician, Tabriz, Iran; Nils Kaageson-Loe, technology leader / drilling and completion fluids at Baker Hughes, Houston; and James Macnaghten, CEO at Caldera Heat Batteries Ltd., Portsmouth, United Kingdom.


Does your company, agency or university have a job opening, new research, new product or other news you’d like to share? I would love to hear from you. Please contact newsletter editor Ben Welter at


RAL Quality MarkThis newsletter is made possible through the generous support of the RAL Quality Association PCM and the members listed below. To learn more about the association, including membership benefits, please contact Stefan Thomann, executive director, at

Axiotherm GmbH | Croda International Plc. | ISU Chemical Co. Ltd. | RuhrTech | Microtek Laboratories | PCM Technology | PLUSS Advanced Technologies | PureTemp LLC | Rubitherm Technologies GmbH | Sasol Germany GmbH | S.Lab Asia Inc. | Sunamp Ltd. | va-Q-tec AG