Thermal energy storage: Some recent developments

Thermal energy storage is a technology that can store heat or cold energy (as thermal energy) for a period of time, so it can be used on demand. Thermal energy storage can be used to store solar energy collected during the daytime to be used at night, or to store energy from a geothermal power plant to be used during periods of peak demand.

In order to explore some recent R&D in thermal energy storage, I used this Mergeflow snapshot as my starting point (click on the image to see the snapshot):

Thermal energy storage, data snapshot from Mergeflow, containing some recent venture investments, market estimates, as well as patents, R&D, and news.

One of my first stops was this article, which explains some of the materials that play a role in thermal energy storage. They are called phase change materials (for this link to work, you need a Mergeflow account; if you don’t have one, you can get a free trial here).

Next, I zoomed in on some companies and R&D. Companies first, then R&D.

Energy Dome: Using CO2 to store electricity

The Italian company Energy Dome uses CO2 for long-term power storage for solar energy. Here is how it works: A mechanical storage device stores electric power by liquifying CO2. As the CO2 is liquified, heat is generated and stored. In order to get the electricity back, the CO2 is regasified in a turbo expander. In other words, Energy Dome makes a CO2 battery.

Energy Dome makes CO2 batteries for storing electricity. Image from energydome.com.
Energy Dome makes CO2 batteries for storing electricity. Image from energydome.com.

Energy Dome just raised $12M Series A, from 360 Capital, Barclays’ Sustainable Impact Capital, Novum Capital Partners, Third Derivative, and others. Energy Dome plans to invest the funds in a CO2 battery demonstration project in Sardinia.

MGA Thermal: Storing energy in shoebox-sized devices

Got some empty shoeboxes? Perhaps MGA Thermal can repurpose them for you. Or, rather, they could repurpose the place where you stack those shoeboxes. This is because MGA Thermal makes stackable thermal energy storage devices. MGA Thermal is an Australian company, and they use a new kind of thermal storage material, called miscibility gap alloys.

Arden Jarrett, from MGA Thermal, holding a thermal storage device. Image from mgathermalstorage.com.
Arden Jarrett, from MGA Thermal, holding a thermal storage device. Image from mgathermalstorage.com.

MGA Thermal raised $8M AUD from Main Sequence, Alberts Impact Capital, New Zealand’s Climate Venture Capital Fund, The Melt, CP Ventures, and others.

Axiom Cloud: Software for managing refrigeration and cooling systems

If you are a food company, or a food store chain, for example, you probably have a refrigeration and cooling infrastructure to maintain. Axiom Cloud makes software for this purpose. Their software not only diagnoses and analyzes system data, so you can keep an eye on things and fix them before they break in an even more expensive way (this is often called predictive maintenance).

Axiom Cloud's Virtual Battery app. Image from axiomcloud.ai.
Axiom Cloud’s Virtual Battery app. Image from axiomcloud.ai.

What I found particularly interesting is their Virtual Battery app. The idea behind this app is to “transform your frozen inventory into an intelligent thermal battery” (this is their words). This allows you to optimize refrigeration loads and flexible, or volatile, electricity rates.

Thermal energy storage R&D

Next, after companies, I looked at some R&D in thermal energy storage. I did this by zooming in on some people who are central in the co-author network that Mergeflow extracted from science publications. Here is a screenshot (click on the image to see it in full size):

Co-author network of thermal energy storage scientists, extracted by Mergeflow from science publications.
Co-author network of thermal energy storage scientists, extracted by Mergeflow from science publications.

Specifically, I focused on the people marked by blue arrows in the screenshot above; Thomas Bauer, Kasper Moth-Poulsen, and Luiza Cabeza.

Using molten salts for thermal energy storage

Thomas Bauer is a researcher at the German Aerospace Center. He and his collaborators examine molten salts for thermal energy storage. Here is one of their more recent papers:

Simulation-Assisted Determination of the Minimum Melting Temperature Composition of MgCl2–KCl–NaCl Salt Mixture for Next-Generation Molten Salt Thermal Energy Storage

In order to get a quick overview of some of the materials they investigate, I used Mergeflow’s chemical molecules detection algorithm. Based on common contexts, this algorithm drew me this network graph:

Materials investigated by Thomas Bauer and colleagues, extracted from science publications by Mergeflow's chemical molecules detection algorithm.
Materials investigated by Thomas Bauer and colleagues, extracted from science publications by Mergeflow’s chemical molecules detection algorithm.

Hydrocarbons for solar energy storage

Kasper Moth-Poulsen, from Chalmers University, investigates materials for capturing solar energy. Again using Mergeflow’s chemical molecules detection algorithm, I saw that norbornadiene seems to play a central role in this research:

Norbornadiene is among the materials investigated by Kasper Moth-Poulsen in the context of thermal energy storage. Screenshot from Mergeflow.
Norbornadiene is among the materials investigated by Kasper Moth-Poulsen in the context of thermal energy storage. Screenshot from Mergeflow.

For example, here is one of their recent publications:

Engineering of Norbornadiene/Quadricyclane Photoswitches for Molecular Solar Thermal Energy Storage Applications

Magnesium-based macro-cellular foams

Macro-cellular foam is a type of foam that is made up of large cells. It is typically used in applications where a high level of support is needed, such as in mattresses and upholstered furniture. Macro-cellular foam can also be used in packaging and insulation applications.

And the “insulation” part is, I think, where it starts to get interesting in our context of thermal storage.

Luisa Cabeza, from the University of Lleida, and her colleagues investigate a subset of macro-cellular foams, ones that are magnesium-based. For example, here is a paper from 2019:

Magnesium sulphate-silicone foam composites for thermochemical energy storage: Assessment of dehydration behaviour and mechanical stability

And here is the corresponding “materials network” extracted by Mergeflow:

Materials investigated by Luisa Cabeza and colleagues include magnesium-based macro-cellular foams. Screenshot from Mergeflow.
Materials investigated by Luisa Cabeza and colleagues include magnesium-based macro-cellular foams. Screenshot from Mergeflow.


Featured image of this article by Mlenny from Getty Images Signature.

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