Credit: Fraunhofer FEP
Heat exchanger with metallized zeolite.
In Germany, 55 percent of final energy consumption goes towards heating and cooling. However, a lot of heat dissipates unused because it is not generated as and when required. Thermal storage using zeolite material allows heat to be stored for long periods of time without losing any. Fraunhofer researchers are now working on significantly improving the thermal conductivity of zeolites.
Many roofs nowadays host solar collectors that provide homes with warm water. This works quite well in the summer; however, heating demand peaks in the winter when homes need heating. Thermal storage therefore needs to be able to store a portion of the excess heat for use at a later date. Traditionally, large water tanks have been used for this purpose; water is heated in these tanks and the heat is then directly stored as heat. The problem with this method is that large volumes are required, and in spite of good insulation, heat is also lost. In contrast, thermochemical storage enables thermal energy produced in the summer to be preserved for use in the cold winter. Zeolites are one such storage solution. Unlike water, zeolites do not store the heat directly – instead, the heat removes the water that is stored within the material. In the energetic state, zeolites are therefore completely dry; conversely, when water vapor is passed through the pellets, heat is released. The advantage of this is that the energy is not stored in the form of increased heat but in the form of a chemical state. This means that heat is not lost during long-term storage. There is one drawback: Zeolites have poor thermal conductivity, which makes transferring the heat from the heat exchanger to the material and back difficult.
Coating with aluminum
A team of researchers at the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP have now solved this problem through their work on the ZeoMet project. “We coated the zeolite pellets with aluminum – this doubled thermal conductivity after just the first attempt without negatively impacting water adsorption and desorption. We are currently aiming to increase this by five to ten times through adjusting the coatings,” says Dr. Heidrun Klostermann, Project Manager at Fraunhofer FEP. While this sounds relatively simple, it actually poses considerable challenges. This means that for a liter of granules with a five millimeter-diameter grain size, around ten thousand of these tiny pellets must be evenly coated with aluminum. For a grain size of one millimeter, this amounts to one million pellets with an overall surface area of 3.6 m2. The smaller the grain, the more challenging the process. However, smaller grains also increase the specific power density of thermal storage systems. In order to achieve sufficient thermal conductivity, the coat must also be tens of micrometers thick – for vacuum coating processes, this is a lot thicker than the norm.
Nevertheless, the researchers conquered these challenges. To do so, they looked to thermal evaporation, whereby aluminum wire is continuously fed onto a heated ceramic plate in a vacuum, where the aluminum is evaporated and deposited onto the granules as a layer of aluminum. The pellets must be continually circulated in a barrel so that they are all covered evenly. “The main difficulty lay in coating the granules while they roll around as well as ensuring that the coating was applied evenly to a sufficient degree,” says Klostermann. “The excellent collaboration of our engineers, physicists and precision mechanics was the principal asset in helping us to achieve.
Also an option for cooling
Not only are zeolites a good method of thermal storage: They can also help provide cooling for domestic use alongside solar collectors as well as for mobile applications. For example, in commercial vehicles, heat lost from the power unit could be used for air conditioning as part of a thermochemical cycle. From the viewpoint of the Fraunhofer FEP researchers, the hybrid materials used for this present new challenges. As a result, the scientists are looking to strengthen their connections with materials developers and systems engineers from research and industry, in the hopes of advancing solutions for the flexible supply of heating and cooling.
Original Article: Thermal storage for the energy transition
More from: Fraunhofer Society
The Latest Updates from Bing News & Google News
Go deeper with Bing News on:
Thermal energy storage
- IPCL and E2S Power to develop thermal energy storage systemon May 9, 2024 at 4:09 am
Thermal energy storage system technology developed by E2S Power will play a key role in India's pursuit of net zero emissions.
- IPCL, E2S to develop Thermal Energy Storage System for efficient storage, transmissionon May 8, 2024 at 4:54 am
The 250Kwh TESS, developed by E2S, has been synchronized with the IPCL system and will help the company achieve its goal of integrating 80 per cent renewable energy into the distribution system by the ...
- Thermal Energy Storage Innovation: IPCL and E2S Collaborate on Efficient Storage and Transmissionon May 8, 2024 at 4:10 am
India Power and E2S collaborate to establish Thermal Energy Storage System (TESS) for energy efficiency. The 250Kwh TESS, integrated with IPCL, supports the company's goal of integrating 80% renewable ...
- Thermal Energy Storage Market to Grow at CAGR of 15% through 2033 - Advancements in TES Technology to Bolster Growthon May 6, 2024 at 2:00 am
Newark, May 06, 2024 (GLOBE NEWSWIRE) -- The Brainy Insights estimates that the USD 5 billion in 2023 global thermal energy storage market will reach USD 20.22 billion in 2033. The energy that a ...
- Air Conditioning Has a Big Climate Impact. This New Technology Could be a Game Changeron April 16, 2024 at 12:54 pm
The 1.4-megawatt-hour IceBrick™ thermal storage technology, developed by the startup Nostromo Energy, uses water to generate ice during periods of low energy demand, typically when the grid is ...
Go deeper with Google Headlines on:
Thermal energy storage
[google_news title=”” keyword=”thermal energy storage” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]
Go deeper with Bing News on:
Long-term energy storage
- Understanding the Challenges of Long-Distance Hydrogen Transport & Storageon May 13, 2024 at 10:02 am
Over the years, hydrogen has gained acclaim as a clean and efficient alternative to conventional fossil fuels such as coal and natural gas. The International Energy Agency notes that global use of ...
- Why Atmos Energy (ATO) is a Top Growth Stock for the Long-Termon May 13, 2024 at 6:45 am
The Zacks Style Scores offers investors a way to easily find top-rated stocks based on their investing style. Here's why you should take advantage.
- NSW seeks a gigawatt of long duration storage, and access rights to 4GW in new renewable zoneon May 12, 2024 at 9:51 pm
The next tender for long duration storage and the first auction of access rights to one of the state’s biggest renewable energy zones will commence this month.
- Ontario's IESO selects 1.8 GW of long term battery storage projectson May 12, 2024 at 7:39 pm
Last week, the Ontario government announced the evaluation of Proposals for the Long-Term 1 RFP and its final bidding result, which includes 10 battery storage system proponents. Their total contact ...
- Researchers think old oil and gas reservoirs could be repurposed to store clean energy: 'Hydrogen would be good for seasonal and long-term storage'on May 11, 2024 at 1:00 am
"If we want to create a hydrogen economy, we really need widely distributed means of storing large quantities of hydrogen." ...
Go deeper with Google Headlines on:
Long-term energy storage
[google_news title=”” keyword=”long-term energy storage” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]