Argonne Technology Puts Solar Power to Work All Night Long
September 19, 2016 | Argonne National LaboratoryEstimated reading time: 3 minutes
Energy storage is crucial for taking full advantage of solar power, which otherwise suffers interruptions from cloudy skies and nightfall. In the past few years, concentrating solar power plants have begun producing additional electricity at night and during peak demand periods by using stored heat energy to propel a steam turbine.
Current thermal energy storage systems rely on materials that store less energy per kilogram, requiring more material at a greater cost to meet energy storage requirements.
Now, researchers at the U.S. Department of Energy’s (DOE’s) Argonne National Laboratory have designed an inexpensive thermal energy storage system that will be significantly smaller and perform more than 20 times better than current thermal systems.
With funding from DOE’s SunShot Initiative, the Argonne team is building a pilot-scale prototype of their high-efficiency latent heat thermal energy storage system (LHTES) for testing. The SunShot Initiative is a national collaborative effort to make unsubsidized solar energy cost-competitive with other forms of electricity production by 2020.
Argonne’s thermal energy storage system relies on a “phase-change” material that melts as it stores thermal energy and releases energy as it re-freezes — similar to the charge-discharge cycle in a battery.
Inexpensive salts like rock salt (sodium chloride) can be used as phase-change materials, but their use in existing thermal storage systems is limited because of the poor thermal conductivity of the salts.
However, the Argonne LHTES system drastically improves the conductivity of these salts by integrating them with a high-conductivity graphite foam. This combination reduces the overall amount of material needed to build the system and its cost, while making the thermal energy transfer significantly more efficient and still providing up to 8 to 12 hours of energy storage — a typical night of storage for a concentrating solar power plant.
“Phase-change materials tend to have low conductivity but meet the heat energy storage requirements,” said Dileep Singh, leader of Argonne’s Thermal-Mechanical Technologies group. “High-conductivity graphite foam meets the conductivity requirements, so we thought: why not combine the two?”
The porous graphite foam traps the salts in pores, facilitating rapid melting and freezing. The team demonstrated that this rapid phase change holds up over time. After building and testing an initial prototype about the size of a blender, the team is now scaling up the prototype size by 50 times.
Although still smaller than a full-scale power plant system, the pilot-scale modular system will be tested this fall and could expand on applications, such as providing back-up power on a microgrid or storing waste heat from another energy source. The pilot system will also further improve 3-D thermal modeling used for estimating performance and planning the design of a full-scale system.
“We are looking at developing the full-scale power plant system as a modular system, and the pilot-scale system we are building this year can actually be used as one module within a full-scale system that is made of many modules stacked or organized together,” said Argonne mechanical engineer Wenhua Yu. “Therefore, the performance characteristics we will measure from testing the pilot can directly reflect those of a power plant system.”
The full-scale design is expected to meet the needs of current power plants that operate steam turbines at about 450 to 600 degrees Celsius (850-1100 degrees Fahrenheit) using magnesium chloride as the storage medium. When advanced supercritical carbon dioxide turbines — which are more efficient than steam turbines but operate at a hotter 700 degrees Celsius (1,300 degrees Fahrenheit) — come online, the same design can be used with sodium chloride.
This work is supported by the DOE SunShot Initiative.
The SunShot Initiative is a collaborative national effort that aggressively drives innovation to make solar energy fully cost-competitive with traditional energy sources before the end of the decade. Through SunShot, the DOE supports efforts by private companies, universities, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour. Learn more at energy.gov/sunshot.
About Argonne National Laboratory
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
Suggested Items
Real Time with... IPC APEX EXPO 2024: AI Implementation at Omron
04/18/2024 | Real Time with...IPC APEX EXPOEditor Nolan Johnson and Omron Product Manager Nick Fieldhouse discuss the company's focus on AI implementation to enhance customer experience and results. They address programming challenges and how AI can help customers achieve better outcomes with less experience. Omron's AI is compatible with existing systems, facilitating easy upgrades.
Cadence Unveils Palladium Z3 and Protium X3 Systems
04/18/2024 | Cadence Design SystemsThe Palladium Z3 and Protium X3 systems offer increased capacity, and scale from job sizes of 16 million gates up to 48 billion gates, so the largest SoCs can be tested as a whole rather than just partial models, ensuring proper functionality and performance.
Real Time with... IPC APEX EXPO 2024: MYCRONIC's Evolution and New Solutions
04/17/2024 | Real Time with...IPC APEX EXPOHenry Crandall interviews Kevin Clue, the vice president of global sales for MYCRONIC's High Flex division. They discuss the company's evolution, emphasizing its strong customer relationships and its role as a versatile, turnkey solution provider. Kevin unveils new solutions launched at IPC APEX EXPO, including an AI-integrated inspection system and the A40 pick-and-place platform. The conversation also touches on the increased use of AI and deep learning.
Australian Flow Batteries and The SCHMID Group Announce Groundbreaking Memorandum of Understanding
04/17/2024 | SCHMID GroupAustralian Flow Batteries Pty Ltd (AFB), a leader in innovative energy solutions and economical, safe, and reliable power storage, and SCHMID Energy Systems GmbH a company of the German SCHMID Group, a global technology leader with a rich history in delivering innovative solutions across multiple industries including Electronics, Renewables, and Energy Storage sectors, are thrilled to announce the signing of a Memorandum of Understanding (MoU)
Ansys Joins BAE Systems’ Mission Advantage Program to Advance Digital Engineering Across US Department of Defense
04/16/2024 | ANSYSAnsys announced it is working with BAE Systems, Inc., to accelerate the adoption of digital engineering and MBSE across the Department of Defense (DoD).