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      Alumnus’ thermal battery helps industry eliminate fossil fuels

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      The explosion of renewable energy projects around the globe is leading to a saturation problem. As more renewable power contributes to the grid, the value of electricity is plummeting during the times of day when wind and solar hit peak productivity. The problem is limiting renewable energy investments in some of the sunniest and windiest places in the world.

      Now Antora Energy, co-founded by David Bierman SM ’14, PhD ’17, is addressing the intermittent nature of wind and solar with a low-cost, highly efficient thermal battery that stores electricity as heat to allow manufacturers and other energy-hungry businesses to eliminate their use of fossil fuels.

      “We take electricity when it’s cheapest, meaning when wind gusts are strongest and the sun is shining brightest,” Bierman explains. “We run that electricity through a resistive heater to drive up the temperature of a very inexpensive material — we use carbon blocks, which are extremely stable, produced at incredible scales, and are some of the cheapest materials on Earth. When you need to pull energy from the battery, you open a large shutter to extract thermal radiation, which is used to generate process heat or power using our thermophotovoltaic, or TPV, technology. The end result is a zero-carbon, flexible, combined heat and power system for industry.”

      Antora’s battery could dramatically expand the application of renewable energy by enabling its use in industry, a sector of the U.S. economy that accounted for nearly a quarter of all greenhouse gas emissions in 2021.

      Antora says it is able to deliver on the long-sought promise of heat-to-power TPV technology because it has achieved new levels of efficiency and scalability with its cells. Earlier this year, Antora opened a new manufacturing facility that will be capable of producing 2 megawatts of its TPV cells each year — which the company says makes it the largest TPV production facility in the world.

      Antora’s thermal battery manufacturing facilities and demonstration unit are located in sun-soaked California, where renewables make up close to a third of all electricity. But Antora’s team says its technology holds promise in other regions as increasingly large renewable projects connect to grids across the globe.

      “We see places today [with high renewables] as a sign of where things are going,” Bierman says. “If you look at the tailwinds we have in the renewable industry, there’s a sense of inevitability about solar and wind, which will need to be deployed at incredible scales to avoid a climate catastrophe. We’ll see terawatts and terawatts of new additions of these renewables, so what you see today in California or Texas or Kansas, with significant periods of renewable overproduction, is just the tip of the iceberg.”

      Bierman has been working on thermal energy storage and thermophotovoltaics since his time at MIT, and Antora’s ties to MIT are especially strong because its progress is the result of two MIT startups becoming one.

      Alumni join forces

      Bierman did his masters and doctoral work in MIT’s Department of Mechanical Engineering, where he worked on solid-state solar thermal energy conversion systems. In 2016, while taking course 15.366 (Climate and Energy Ventures), he met Jordan Kearns SM ’17, then a graduate student in the Technology and Policy Program and the Department of Nuclear Science and Engineering. The two were studying renewable energy when they began to think about the intermittent nature of wind and solar as an opportunity rather than a problem.

      “There are already places in the U.S. where we have more wind and solar at times than we know what to do with,” Kearns says. “That is an opportunity for not only emissions reductions but also for reducing energy costs. What’s the application? I don’t think the overproduction of energy was being talked about as much as the intermittency problem.”

      Kearns did research through the MIT Energy Initiative and the researchers received support from MIT’s Venture Mentoring Service and the MIT Sandbox Innovation Fund to further explore ways to capitalize on fluctuating power prices.

      Kearns officially founded a company called Medley Thermal in 2017 to help companies that use natural gas switch to energy produced by renewables when the price was right. To accomplish that, he combined an off-the-shelf electric boiler with novel control software so the companies could switch energy sources seamlessly from fossil fuel to electricity at especially windy or sunny times. Medley went on to become a finalist for the MIT Clean Energy Prize, and Kearns wanted Bierman to join him as a co-founder, but Bierman had received a fellowship to commercialize a thermal energy storage solution and decided to pursue that after graduation.

      The split ended up working out for both alumni. In the ensuing years, Kearns led Medley Thermal through a number of projects in which gradually larger companies switched from relying on natural gas or propane sources to renewable electricity from the grid. The work culminated in an installment at the Jay Peak resort in Vermont that Kearns says is one of the largest projects in the U.S. using renewable energy to produce heat. The project is expected to reduce about 2,500 tons of carbon dioxide per year.

      Bierman, meanwhile, further developed a thermal energy storage solution for industrial decarbonization, which works by using renewable electricity to heat blocks of carbon, which are stored in insulation to retain energy for long periods of time. The heat from those blocks can then be used to deliver electricity or heat to customers, at temperatures that can exceed 1,500 C. When Antora raised a $50 million Series A funding round last year, Bierman asked Kearns if he could buy out Medley’s team, and the researchers finally became co-workers.

      “Antora and Medley Thermal have a similar value prop: There’s low-cost electricity, and we want to connect that to the industrial sector,” Kearns explains. “But whereas Medley used renewables on an as-available basis, and then when the winds stop we went back to burning fossil fuel with a boiler, Antora has a thermal battery that takes in the electricity, converts it to heat, but also stores it as heat so even when the wind stops blowing we have a reservoir of heat that we can continue to pull from to make steam or power or whatever the facility needs. So, we can now further reduce energy costs by offsetting more fuel and offer a 100 percent clean energy solution.”

      United we scale

      Today, Kearns runs the project development arm of Antora.

      “There are other, much larger projects in the pipeline,” Kearns says. “The Jay Peak project is about 3 megawatts of power, but some of the ones we’re working on now are 30, 60 megawatt projects. Those are more industrial focused, and they’re located in places where we have a strong industrial base and an abundance of renewables, everywhere from Texas to Kansas to the Dakotas — that heart of the country that our team lovingly calls the Wind Belt.”

      Antora’s future projects will be with companies in the chemicals, mining, food and beverage, and oil and gas industries. Some of those projects are expected to come online as early as 2025.          

      The company’s scaling strategy is centered on the inexpensive production process for its batteries.

      “We constantly ask ourselves, ‘What is the best product we can make here?’” Bierman says. “We landed on a compact, containerized, modular system that gets shipped to sites and is easily integrated into industrial processes. It means we don’t have huge construction projects, timelines, and budget overruns. Instead, it’s all about scaling up the factory that builds these thermal batteries and just churning them out.”

      It was a winding journey for Kearns and Bierman, but they now believe they’re positioned to help huge companies become carbon-free while promoting the growth of the solar and wind industries.

      “The more I dig into this, the more shocked I am at how important a piece of the decarbonization puzzle this is today,” Bierman says. “The need has become super real since we first started talking about this in 2016. The economic opportunity has grown, but more importantly the awareness from industries that they need to decarbonize is totally different. Antora can help with that, so we’re scaling up as rapidly as possible to meet the demand we see in the market.” More

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      To improve solar and other clean energy tech, look beyond hardware

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      To continue reducing the costs of solar energy and other clean energy technologies, scientists and engineers will likely need to focus, at least in part, on improving technology features that are not based on hardware, according to MIT researchers. They describe this finding and the mechanisms behind it today in Nature Energy.

      While the cost of installing a solar energy system has dropped by more than 99 percent since 1980, this new analysis shows that “soft technology” features, such as the codified permitting practices, supply chain management techniques, and system design processes that go into deploying a solar energy plant, contributed only 10 to 15 percent of total cost declines. Improvements to hardware features were responsible for the lion’s share.

      But because soft technology is increasingly dominating the total costs of installing solar energy systems, this trend threatens to slow future cost savings and hamper the global transition to clean energy, says the study’s senior author, Jessika Trancik, a professor in MIT’s Institute for Data, Systems, and Society (IDSS).

      Trancik’s co-authors include lead author Magdalena M. Klemun, a former IDSS graduate student and postdoc who is now an assistant professor at the Hong Kong University of Science and Technology; Goksin Kavlak, a former IDSS graduate student and postdoc who is now an associate at the Brattle Group; and James McNerney, a former IDSS postdoc and now senior research fellow at the Harvard Kennedy School.

      The team created a quantitative model to analyze the cost evolution of solar energy systems, which captures the contributions of both hardware technology features and soft technology features.

      The framework shows that soft technology hasn’t improved much over time — and that soft technology features contributed even less to overall cost declines than previously estimated.

      Their findings indicate that to reverse this trend and accelerate cost declines, engineers could look at making solar energy systems less reliant on soft technology to begin with, or they could tackle the problem directly by improving inefficient deployment processes.  

      “Really understanding where the efficiencies and inefficiencies are, and how to address those inefficiencies, is critical in supporting the clean energy transition. We are making huge investments of public dollars into this, and soft technology is going to be absolutely essential to making those funds count,” says Trancik.

      “However,” Klemun adds, “we haven’t been thinking about soft technology design as systematically as we have for hardware. That needs to change.”

      The hard truth about soft costs

      Researchers have observed that the so-called “soft costs” of building a solar power plant — the costs of designing and installing the plant — are becoming a much larger share of total costs. In fact, the share of soft costs now typically ranges from 35 to 64 percent.

      “We wanted to take a closer look at where these soft costs were coming from and why they weren’t coming down over time as quickly as the hardware costs,” Trancik says.

      In the past, scientists have modeled the change in solar energy costs by dividing total costs into additive components — hardware components and nonhardware components — and then tracking how these components changed over time.

      “But if you really want to understand where those rates of change are coming from, you need to go one level deeper to look at the technology features. Then things split out differently,” Trancik says.

      The researchers developed a quantitative approach that models the change in solar energy costs over time by assigning contributions to the individual technology features, including both hardware features and soft technology features.

      For instance, their framework would capture how much of the decline in system installation costs — a soft cost — is due to standardized practices of certified installers — a soft technology feature. It would also capture how that same soft cost is affected by increased photovoltaic module efficiency — a hardware technology feature.

      With this approach, the researchers saw that improvements in hardware had the greatest impacts on driving down soft costs in solar energy systems. For example, the efficiency of photovoltaic modules doubled between 1980 and 2017, reducing overall system costs by 17 percent. But about 40 percent of that overall decline could be attributed to reductions in soft costs tied to improved module efficiency.

      The framework shows that, while hardware technology features tend to improve many cost components, soft technology features affect only a few.

      “You can see this structural difference even before you collect data on how the technologies have changed over time. That’s why mapping out a technology’s network of cost dependencies is a useful first step to identify levers of change, for solar PV and for other technologies as well,” Klemun notes.  

      Static soft technology

      The researchers used their model to study several countries, since soft costs can vary widely around the world. For instance, solar energy soft costs in Germany are about 50 percent less than those in the U.S.

      The fact that hardware technology improvements are often shared globally led to dramatic declines in costs over the past few decades across locations, the analysis showed. Soft technology innovations typically aren’t shared across borders. Moreover, the team found that countries with better soft technology performance 20 years ago still have better performance today, while those with worse performance didn’t see much improvement.

      This country-by-country difference could be driven by regulation and permitting processes, cultural factors, or by market dynamics such as how firms interact with each other, Trancik says.

      “But not all soft technology variables are ones that you would want to change in a cost-reducing direction, like lower wages. So, there are other considerations, beyond just bringing the cost of the technology down, that we need to think about when interpreting these results,” she says.

      Their analysis points to two strategies for reducing soft costs. For one, scientists could focus on developing hardware improvements that make soft costs more dependent on hardware technology variables and less on soft technology variables, such as by creating simpler, more standardized equipment that could reduce on-site installation time.

      Or researchers could directly target soft technology features without changing hardware, perhaps by creating more efficient workflows for system installation or automated permitting platforms.

      “In practice, engineers will often pursue both approaches, but separating the two in a formal model makes it easier to target innovation efforts by leveraging specific relationships between technology characteristics and costs,” Klemun says.

      “Often, when we think about information processing, we are leaving out processes that still happen in a very low-tech way through people communicating with one another. But it is just as important to think about that as a technology as it is to design fancy software,” Trancik notes.

      In the future, she and her collaborators want to apply their quantitative model to study the soft costs related to other technologies, such as electrical vehicle charging and nuclear fission. They are also interested in better understanding the limits of soft technology improvement, and how one could design better soft technology from the outset.

      This research is funded by the U.S. Department of Energy Solar Energy Technologies Office. More

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      Simple superconducting device could dramatically cut energy use in computing, other applications

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      MIT scientists and their colleagues have created a simple superconducting device that could transfer current through electronic devices much more efficiently than is possible today. As a result, the new diode, a kind of switch, could dramatically cut the amount of energy used in high-power computing systems, a major problem that is estimated to become much worse. Even though it is in the early stages of development, the diode is more than twice as efficient as similar ones reported by others. It could even be integral to emerging quantum computing technologies.

      The work, which is reported in the July 13 online issue of Physical Review Letters, is also the subject of a news story in Physics Magazine.

      “This paper showcases that the superconducting diode is an entirely solved problem from an engineering perspective,” says Philip Moll, director of the Max Planck Institute for the Structure and Dynamics of Matter in Germany. Moll was not involved in the work. “The beauty of [this] work is that [Moodera and colleagues] obtained record efficiencies without even trying [and] their structures are far from optimized yet.”

      “Our engineering of a superconducting diode effect that is robust and can operate over a wide temperature range in simple systems can potentially open the door for novel technologies,” says Jagadeesh Moodera, leader of the current work and a senior research scientist in MIT’s Department of Physics. Moodera is also affiliated with the Materials Research Laboratory, the Francis Bitter Magnet Laboratory, and the Plasma Science and Fusion Center (PSFC).

      The nanoscopic rectangular diode — about 1,000 times thinner than the diameter of a human hair — is easily scalable. Millions could be produced on a single silicon wafer.

      Toward a superconducting switch

      Diodes, devices that allow current to travel easily in one direction but not in the reverse, are ubiquitous in computing systems. Modern semiconductor computer chips contain billions of diode-like devices known as transistors. However, these devices can get very hot due to electrical resistance, requiring vast amounts of energy to cool the high-power systems in the data centers behind myriad modern technologies, including cloud computing. According to a 2018 news feature in Nature, these systems could use nearly 20 percent of the world’s power in 10 years.

      As a result, work toward creating diodes made of superconductors has been a hot topic in condensed matter physics. That’s because superconductors transmit current with no resistance at all below a certain low temperature (the critical temperature), and are therefore much more efficient than their semiconducting cousins, which have noticeable energy loss in the form of heat.

      Until now, however, other approaches to the problem have involved much more complicated physics. “The effect we found is due [in part] to a ubiquitous property of superconductors that can be realized in a very simple, straightforward manner. It just stares you in the face,” says Moodera.

      Says Moll of the Max Planck Institute, “The work is an important counterpoint to the current fashion to associate superconducting diodes [with] exotic physics, such as finite-momentum pairing states. While in reality, a superconducting diode is a common and widespread phenomenon present in classical materials, as a result of certain broken symmetries.”

      A somewhat serendipitous discovery

      In 2020 Moodera and colleagues observed evidence of an exotic particle pair known as Majorana fermions. These particle pairs could lead to a new family of topological qubits, the building blocks of quantum computers. While pondering approaches to creating superconducting diodes, the team realized that the material platform they developed for the Majorana work might also be applied to the diode problem.

      They were right. Using that general platform, they developed different iterations of superconducting diodes, each more efficient than the last. The first, for example, consisted of a nanoscopically thin layer of vanadium, a superconductor, which was patterned into a structure common to electronics (the Hall bar). When they applied a tiny magnetic field comparable to the Earth’s magnetic field, they saw the diode effect — a giant polarity dependence for current flow.

      They then created another diode, this time layering a superconductor with a ferromagnet (a ferromagnetic insulator in their case), a material that produces its own tiny magnetic field. After applying a tiny magnetic field to magnetize the ferromagnet so that it produces its own field, they found an even bigger diode effect that was stable even after the original magnetic field was turned off.

      Ubiquitous properties

      The team went on to figure out what was happening.

      In addition to transmitting current with no resistance, superconductors also have other, less well-known but just as ubiquitous properties. For example, they don’t like magnetic fields getting inside. When exposed to a tiny magnetic field, superconductors produce an internal supercurrent that induces its own magnetic flux that cancels the external field, thereby maintaining their superconducting state. This phenomenon, known as the Meissner screening effect, can be thought of as akin to our bodies’ immune system releasing antibodies to fight the infection of bacteria and other pathogens. This works, however, only up to some limit. Similarly, superconductors cannot entirely keep out large magnetic fields.

      The diodes the team created make use of this universal Meissner screening effect. The tiny magnetic field they applied — either directly, or through the adjacent ferromagnetic layer — activates the material’s screening current mechanism for expelling the external magnetic field and maintaining superconductivity.

      The team also found that another key factor in optimizing these superconductor diodes is tiny differences between the two sides, or edges, of the diode devices. These differences “create some sort of asymmetry in the way the magnetic field enters the superconductor,” Moodera says.

      By engineering their own form of edges on diodes to optimize these differences — for example, one edge with sawtooth features, while the other edge not intentionally altered — the team found that they could increase the efficiency from 20 percent to more than 50 percent. This discovery opens the door for devices whose edges could be “tuned” for even higher efficiencies, Moodera says.

      In sum, the team discovered that the edge asymmetries within superconducting diodes, the ubiquitous Meissner screening effect found in all superconductors, and a third property of superconductors known as vortex pinning all came together to produce the diode effect.

      “It is fascinating to see how inconspicuous yet ubiquitous factors can create a significant effect in observing the diode effect,” says Yasen Hou, first author of the paper and a postdoc at the Francis Bitter Magnet Laboratory and the PSFC. “What’s more exciting is that [this work] provides a straightforward approach with huge potential to further improve the efficiency.”

      Christoph Strunk is a professor at the University of Regensburg in Germany. Says Strunk, who was not involved in the research, “the present work demonstrates that the supercurrent in simple superconducting strips can become nonreciprocal. Moreover, when combined with a ferromagnetic insulator, the diode effect can even be maintained in the absence of an external magnetic field. The rectification direction can be programmed by the remnant magnetization of the magnetic layer, which may have high potential for future applications. The work is important and appealing both from the basic research and from the applications point of view.”

      Teenage contributors

      Moodera noted that the two researchers who created the engineered edges did so while still in high school during a summer at Moodera’s lab. They are Ourania Glezakou-Elbert of Richland, Washington, who will be going to Princeton University this fall, and Amith Varambally of Vestavia Hills, Alabama, who will be entering Caltech.

      Says Varambally, “I didn’t know what to expect when I set foot in Boston last summer, and certainly never expected to [be] a coauthor in a Physical Review Letters paper.

      “Every day was exciting, whether I was reading dozens of papers to better understand the diode phenomena, or operating machinery to fabricate new diodes for study, or engaging in conversations with Ourania, Dr. Hou, and Dr. Moodera about our research.

      “I am profoundly grateful to Dr. Moodera and Dr. Hou for providing me with the opportunity to work on such a fascinating project, and to Ourania for being a great research partner and friend.”

      In addition to Moodera and Hou, corresponding authors of the paper are professors Patrick A. Lee of the MIT Department of Physics and Akashdeep Kamra of Autonomous University of Madrid. Other authors from MIT are Liang Fu and Margarita Davydova of the Department of Physics, and Hang Chi, Alessandro Lodesani, and Yingying Wu, all of the Francis Bitter Magnet Laboratory and the Plasma Science and Fusion Center. Chi is also affiliated with the U.S. Army CCDC Research Laboratory.

      Authors also include Fabrizio Nichele, Markus F. Ritter, and Daniel Z. Haxwell of IBM Research Europe; Stefan Ilićof Materials Physics Center (CFM-MPC); and F. Sebastian Bergeret of CFM-MPC and Donostia International Physics Center.

      This work was supported by the Air Force Office of Sponsored Research, the Office of Naval Research, the National Science Foundation, and the Army Research Office. Additional funders are the European Research Council, the European Union’s Horizon 2020 Research and Innovation Framework Programme, the Spanish Ministry of Science and Innovation, the A. v. Humboldt Foundation, and the Department of Energy’s Office of Basic Sciences. More

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      in Energy

      A welcome new pipeline for students invested in clean energy

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      Akarsh Aurora aspired “to be around people who are actually making the global energy transition happen,” he says. Sam Packman sought to “align his theoretical and computational interests to a clean energy project” with tangible impacts. Lauryn Kortman says she “really liked the idea of an in-depth research experience focused on an amazing energy source.”

      These three MIT students found what they wanted in the Fusion Undergraduate Scholars (FUSars) program launched by the MIT Plasma Science and Fusion Center (PSFC) to make meaningful fusion energy research accessible to undergraduates. Aurora, Kortman, and Packman are members of a cohort of 10 for the program’s inaugural run, which began spring semester 2023.

      FUSars operates like a high-wattage UROP (MIT’s Undergraduate Research Opportunities Program). The program requires a student commitment of 10 to 12 hours weekly on a research project during the course of an academic year, as well as participation in a for-credit seminar providing professional development, communication, and wellness support. Through this class and with the mentorship of graduate students, postdocs, and research scientist advisors, students craft a publication-ready journal submission summarizing their research. Scholars who complete the entire year and submit a manuscript for review will receive double the ordinary UROP stipend — a payment that can reach $9,000.

      “The opportunity just jumped out at me,” says Packman. “It was an offer I couldn’t refuse,” adds Aurora.

      Building a workforce

      “I kept hearing from students wanting to get into fusion, but they were very frustrated because there just wasn’t a pipeline for them to work at the PSFC,” says Michael Short, Class of ’42 Associate Professor of Nuclear Science and Engineering and associate director of the PSFC. The PSFC bustles with research projects run by scientists and postdocs. But since the PSFC isn’t a university department with educational obligations, it does not have the regular machinery in place to integrate undergraduate researchers.

      This poses a problem not just for students but for the field of fusion energy, which holds the prospect of unlimited, carbon-free electricity. There are promising advances afoot: MIT and one of its partners, Commonwealth Fusion Systems, are developing a prototype for a compact commercial fusion energy reactor. The start of a fusion energy industry will require a steady infusion of skilled talent.

      “We have to think about the workforce needs of fusion in the future and how to train that workforce,” says Rachel Shulman, who runs the FUSars program and co-instructs the FUSars class with Short. “Energy education needs to be thinking right now about what’s coming after solar, and that’s fusion.”

      Short, who earned his bachelor’s, master’s, and doctoral degrees at MIT, was himself the beneficiary of the Undergraduate Research Opportunity Program (UROP) at the PSFC. As a faculty member, he has become deeply engaged in building transformative research experiences for undergraduates. With FUSars, he hopes to give students a springboard into the field — with an eye to developing a diverse, highly trained, and zealous employee pool for a future fusion industry.

      Taking a deep dive

      Although these are early days for this initial group of FUSars, there is already a shared sense of purpose and enthusiasm. Chosen from 32 applicants in a whirlwind selection process — the program first convened in early February after crafting the experience over Independent Activities Period — the students arrived with detailed research proposals and personal goals.

      Aurora, a first-year majoring in mechanical engineering and artificial intelligence, became fixed on fusion while still in high school. Today he is investigating methods for increasing the availability, known as capacity factor, of fusion reactors. “This is key to the commercialization of fusion energy,” he says.

      Packman, a first-year planning on a math and physics double major, is developing approaches to help simplify the computations involved in designing the complex geometries of solenoid induction heaters in fusion reactors. “This project is more immersive than my last UROP, and requires more time, but I know what I’m doing here and how this fits into the broader goals of fusion science,” he says. “It’s cool that our project is going to lead to a tool that will actually be used.”

      To accommodate the demands of their research projects, Shulman and Short discouraged students from taking on large academic loads.

      Kortman, a junior majoring in materials science and engineering with a concentration in mechanical engineering, was eager to make room in her schedule for her project, which concerns the effects of radiation damage on superconducting magnets. A shorter research experience with the PSFC during the pandemic fired her determination to delve deeper and invest more time in fusion.

      “It is very appealing and motivating to join people who have been working on this problem for decades, just as breakthroughs are coming through,” she says. “What I’m doing feels like it might be directly applicable to the development of an actual fusion reactor.”

      Camaraderie and support

      In the FUSar program, students aim to seize a sizeable stake in a multipronged research enterprise. “Here, if you have any hypotheses, you really get to pursue those because at the end of the day, the paper you write is yours,” says Aurora. “You can take ownership of what sort of discovery you’re making.”

      Enabling students to make the most of their research experiences requires abundant support — and not just for the students. “We have a whole separate set of programming on mentoring the mentors, where we go over topics with postdocs like how to teach someone to write a research paper, rather than write it for them, and how to help a student through difficulties,” Shulman says.

      The weekly student seminar, taught primarily by Short and Shulman, covers pragmatic matters essential to becoming a successful researcher — topics not always addressed directly or in the kind of detail that makes a difference. Topics include how to collaborate with lab mates, deal with a supervisor, find material in the MIT libraries, produce effective and persuasive research abstracts, and take time for self-care.

      Kortman believes camaraderie will help the cohort through an intense year. “This is a tight-knit community that will be great for keeping us all motivated when we run into research issues,” she says. “Meeting weekly to see what other students are able to accomplish will encourage me in my own project.”

      The seminar offerings have already attracted five additional participants outside the FUSars cohort. Adria Peterkin, a second-year graduate student in nuclear science and engineering, is sitting in to solidify her skills in scientific writing.

      “I wanted a structured class to help me get good at abstracts and communicating with different audiences,” says Peterkin, who is investigating radiation’s impact on the molten salt used in fusion and advanced nuclear reactors. “There’s a lot of assumed knowledge coming in as a PhD student, and a program like FUSars is really useful to help level out that playing field, regardless of your background.”

      Fusion research for all

      Short would like FUSars to cast a wide net, capturing the interest of MIT undergraduates no matter their backgrounds or financial means. One way he hopes to achieve this end is with the support of private donors, who make possible premium stipends for fusion scholars.

      “Many of our students are economically disadvantaged, on financial aid or supporting family back home, and need work that pays more than $15 an hour,” he says. This generous stipend may be critical, he says, to “flipping students from something else to fusion.”

      Although this first FUSars class is composed of science and engineering students, Short envisions a cohort eventually drawn from the broad spectrum of MIT disciplines. “Fusion is not a nuclear-focused discipline anymore — it’s no longer just plasma physics and radiation,” he says. “We’re trying to make a power plant now, and it’s an all hands-on-deck kind of thing, involving policy and economics and other subjects.”

      Although many are just getting started on their academic journeys, FUSar students believe this year will give them a strong push toward potential energy careers. “Fusion is the future of the energy transition and how we’re going to defeat climate change,” says Aurora. “I joined the program for a deep dive into the field, to help me decide whether I should invest the rest of my life to it.” More

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      in Energy

      Embracing the future we need

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      When you picture MIT doctoral students taking small PhD courses together, you probably don’t imagine them going on class field trips. But it does happen, sometimes, and one of those trips changed Andy Sun’s career.

      Today, Sun is a faculty member at the MIT Sloan School of Management and a leading global expert on integrating renewable energy into the electric grid. Back in 2007, Sun was an operations research PhD candidate with a diversified academic background: He had studied electrical engineering, quantum computing, and analog computing but was still searching for a doctoral research subject involving energy. 

      One day, as part of a graduate energy class taught by visiting professor Ignacio J. Pérez Arriaga, the students visited the headquarters of ISO-New England, the organization that operates New England’s entire power grid and wholesale electricity market. Suddenly, it hit Sun. His understanding of engineering, used to design and optimize computing systems, could be applied to the grid as a whole, with all its connections, circuitry, and need for efficiency. 

      “The power grids in the U.S. continent are composed of two major interconnections, the Western Interconnection, the Eastern Interconnection, and one minor interconnection, the Texas grid,” Sun says. “Within each interconnection, the power grid is one big machine, essentially. It’s connected by tens of thousands of miles of transmission lines, thousands of generators, and consumers, and if anything is not synchronized, the system may collapse. It’s one of the most complicated engineering systems.”

      And just like that, Sun had a subject he was motivated to pursue. “That’s how I got into this field,” he says. “Taking a field trip.”Sun has barely looked back. He has published dozens of papers about optimizing the flow of intermittent renewable energy through the electricity grid, a major practical issue for grid operators, while also thinking broadly about the future form of the grid and the process of making almost all energy renewable. Sun, who in 2022 rejoined MIT as the Iberdrola-Avangrid Associate Professor in Electric Power Systems, and is also an associate professor of operations research, emphasizes the urgency of rapidly switching to renewables.

      “The decarbonization of our energy system is fundamental,” Sun says. “It will change a lot of things because it has to. We don’t have much time to get there. Two decades, three decades is the window in which we have to get a lot of things done. If you think about how much money will need to be invested, it’s not actually that much. We should embrace this future that we have to get to.”

      Successful operations

      Unexpected as it may have been, Sun’s journey toward being an electricity grid expert was informed by all the stages of his higher education. Sun grew up in China, and received his BA in electronic engineering from Tsinghua University in Beijing, in 2003. He then moved to MIT, joining the Media Lab as a graduate student. Sun intended to study quantum computing but instead began working on analog computer circuit design for Professor Neil Gershenfeld, another person whose worldview influenced Sun.  

      “He had this vision about how optimization is very important in things,” Sun says. “I had never heard of optimization before.” 

      To learn more about it, Sun started taking MIT courses in operations research. “I really enjoyed it, especially the nonlinear optimization course taught by Robert Freund in the Operations Research Center,” he recalls. 

      Sun enjoyed it so much that after a while, he joined MIT’s PhD program in operations research, thanks to the guidance of Freund. Later, he started working with MIT Sloan Professor Dimitri Bertsimas, a leading figure in the field. Still, Sun hadn’t quite nailed down what he wanted to focus on within operations research. Thinking of Sun’s engineering skills, Bertsimas suggested that Sun look for a research topic related to energy. 

      “He wasn’t an expert in energy at that time, but he knew that there are important problems there and encouraged me to go ahead and learn,” Sun says. 

      So it was that Sun found himself in ISO-New England headquarters one day in 2007, finally knowing what he wanted to study, and quickly finding opportunities to start learning from the organization’s experts on electricity markets. By 2011, Sun had finished his MIT PhD dissertation. Based in part on ISO-New England data, the thesis presented new modeling to more efficiently integrate renewable energy into the grid; built some new modeling tools grid operators could use; and developed a way to add fair short-term energy auctions to an efficient grid system.

      The core problem Sun deals with is that, unlike some other sources of electricity, renewables tend to be intermittent, generating power in an uneven pattern over time. That’s not an insurmountable problem for grid operators, but it does require some new approaches. Many of the papers Sun has written focus on precisely how to increasingly draw upon intermittent energy sources while ensuring that the grid’s current level of functionality remains intact. This is also the focus of his 2021 book, co-authored with Antonio J. Conejo, “Robust Optimiziation in Electric Energy Systems.”

      “A major theme of my research is how to achieve the integration of renewables and still operate the system reliably,” Sun says. “You have to keep the balance of supply and demand. This requires many time scales of operation from multidecade planning, to monthly or annual maintenance, to daily operations, down through second-by-second. I work on problems in all these timescales.”

      “I sit in the interface between power engineering and operations research,” Sun says. “I’m not a power engineer, but I sit in this boundary, and I keep the problems in optimization as my motivation.”

      Culture shift

      Sun’s presence on the MIT campus represents a homecoming of sorts. After receiving his doctorate from MIT, Sun spent a year as a postdoc at IBM’s Thomas J. Watson Research Center, then joined the faculty at Georgia Tech, where he remained for a decade. He returned to the Institute in January of 2022.

      “I’m just very excited about the opportunity of being back at MIT,” Sun says. “The MIT Energy Initiative is a such a vibrant place, where many people come together to work on energy. I sit in Sloan, but one very strong point of MIT is there are not many barriers, institutionally. I really look forward to working with colleagues from engineering, Sloan, everywhere, moving forward. We’re moving in the right direction, with a lot of people coming together to break the traditional academic boundaries.” 

      Still, Sun warns that some people may be underestimating the severity of the challenge ahead and the need to implement changes right now. The assets in power grids have long life time, lasting multiple decades. That means investment decisions made now could affect how much clean power is being used a generation from now. 

      “We’re talking about a short timeline, for changing something as huge as how a society fundamentally powers itself with energy,” Sun says. “A lot of that must come from the technology we have today. Renewables are becoming much better and cheaper, so their use has to go up.”

      And that means more people need to work on issues of how to deploy and integrate renewables into everyday life, in the electric grid, transportation, and more. Sun hopes people will increasingly recognize energy as a huge growth area for research and applied work. For instance, when MIT President Sally Kornbluth gave her inaugural address on May 1 this year, she emphasized tackling the climate crisis as her highest priority, something Sun noticed and applauded. 

      “I think the most important thing is the culture,” Sun says. “Bring climate up to the front, and create the platform to encourage people to come together and work on this issue.” More

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      in Energy

      MIT engineers create an energy-storing supercapacitor from ancient materials

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      Two of humanity’s most ubiquitous historical materials, cement and carbon black (which resembles very fine charcoal), may form the basis for a novel, low-cost energy storage system, according to a new study. The technology could facilitate the use of renewable energy sources such as solar, wind, and tidal power by allowing energy networks to remain stable despite fluctuations in renewable energy supply.

      The two materials, the researchers found, can be combined with water to make a supercapacitor — an alternative to batteries — that could provide storage of electrical energy. As an example, the MIT researchers who developed the system say that their supercapacitor could eventually be incorporated into the concrete foundation of a house, where it could store a full day’s worth of energy while adding little (or no) to the cost of the foundation and still providing the needed structural strength. The researchers also envision a concrete roadway that could provide contactless recharging for electric cars as they travel over that road.

      The simple but innovative technology is described this week in the journal PNAS, in a paper by MIT professors Franz-Josef Ulm, Admir Masic, and Yang-Shao Horn, and four others at MIT and at the Wyss Institute for Biologically Inspired Engineering.

      Capacitors are in principle very simple devices, consisting of two electrically conductive plates immersed in an electrolyte and separated by a membrane. When a voltage is applied across the capacitor, positively charged ions from the electrolyte accumulate on the negatively charged plate, while the positively charged plate accumulates negatively charged ions. Since the membrane in between the plates blocks charged ions from migrating across, this separation of charges creates an electric field between the plates, and the capacitor becomes charged. The two plates can maintain this pair of charges for a long time and then deliver them very quickly when needed. Supercapacitors are simply capacitors that can store exceptionally large charges.

      The amount of power a capacitor can store depends on the total surface area of its conductive plates. The key to the new supercapacitors developed by this team comes from a method of producing a cement-based material with an extremely high internal surface area due to a dense, interconnected network of conductive material within its bulk volume. The researchers achieved this by introducing carbon black — which is highly conductive — into a concrete mixture along with cement powder and water, and letting it cure. The water naturally forms a branching network of openings within the structure as it reacts with cement, and the carbon migrates into these spaces to make wire-like structures within the hardened cement. These structures have a fractal-like structure, with larger branches sprouting smaller branches, and those sprouting even smaller branchlets, and so on, ending up with an extremely large surface area within the confines of a relatively small volume. The material is then soaked in a standard electrolyte material, such as potassium chloride, a kind of salt, which provides the charged particles that accumulate on the carbon structures. Two electrodes made of this material, separated by a thin space or an insulating layer, form a very powerful supercapacitor, the researchers found.

      The two plates of the capacitor function just like the two poles of a rechargeable battery of equivalent voltage: When connected to a source of electricity, as with a battery, energy gets stored in the plates, and then when connected to a load, the electrical current flows back out to provide power.

      “The material is fascinating,” Masic says, “because you have the most-used manmade material in the world, cement, that is combined with carbon black, that is a well-known historical material — the Dead Sea Scrolls were written with it. You have these at least two-millennia-old materials that when you combine them in a specific manner you come up with a conductive nanocomposite, and that’s when things get really interesting.”

      As the mixture sets and cures, he says, “The water is systematically consumed through cement hydration reactions, and this hydration fundamentally affects nanoparticles of carbon because they are hydrophobic (water repelling).” As the mixture evolves, “the carbon black is self-assembling into a connected conductive wire,” he says. The process is easily reproducible, with materials that are inexpensive and readily available anywhere in the world. And the amount of carbon needed is very small — as little as 3 percent by volume of the mix — to achieve a percolated carbon network, Masic says.

      Supercapacitors made of this material have great potential to aid in the world’s transition to renewable energy, Ulm says. The principal sources of emissions-free energy, wind, solar, and tidal power, all produce their output at variable times that often do not correspond to the peaks in electricity usage, so ways of storing that power are essential. “There is a huge need for big energy storage,” he says, and existing batteries are too expensive and mostly rely on materials such as lithium, whose supply is limited, so cheaper alternatives are badly needed. “That’s where our technology is extremely promising, because cement is ubiquitous,” Ulm says.

      The team calculated that a block of nanocarbon-black-doped concrete that is 45 cubic meters (or yards) in size — equivalent to a cube about 3.5 meters across — would have enough capacity to store about 10 kilowatt-hours of energy, which is considered the average daily electricity usage for a household. Since the concrete would retain its strength, a house with a foundation made of this material could store a day’s worth of energy produced by solar panels or windmills and allow it to be used whenever it’s needed. And, supercapacitors can be charged and discharged much more rapidly than batteries.

      After a series of tests used to determine the most effective ratios of cement, carbon black, and water, the team demonstrated the process by making small supercapacitors, about the size of some button-cell batteries, about 1 centimeter across and 1 millimeter thick, that could each be charged to 1 volt, comparable to a 1-volt battery. They then connected three of these to demonstrate their ability to light up a 3-volt light-emitting diode (LED). Having proved the principle, they now plan to build a series of larger versions, starting with ones about the size of a typical 12-volt car battery, then working up to a 45-cubic-meter version to demonstrate its ability to store a house-worth of power.

      There is a tradeoff between the storage capacity of the material and its structural strength, they found. By adding more carbon black, the resulting supercapacitor can store more energy, but the concrete is slightly weaker, and this could be useful for applications where the concrete is not playing a structural role or where the full strength-potential of concrete is not required. For applications such as a foundation, or structural elements of the base of a wind turbine, the “sweet spot” is around 10 percent carbon black in the mix, they found.

      Another potential application for carbon-cement supercapacitors is for building concrete roadways that could store energy produced by solar panels alongside the road and then deliver that energy to electric vehicles traveling along the road using the same kind of technology used for wirelessly rechargeable phones. A related type of car-recharging system is already being developed by companies in Germany and the Netherlands, but using standard batteries for storage.

      Initial uses of the technology might be for isolated homes or buildings or shelters far from grid power, which could be powered by solar panels attached to the cement supercapacitors, the researchers say.

      Ulm says that the system is very scalable, as the energy-storage capacity is a direct function of the volume of the electrodes. “You can go from 1-millimeter-thick electrodes to 1-meter-thick electrodes, and by doing so basically you can scale the energy storage capacity from lighting an LED for a few seconds, to powering a whole house,” he says.

      Depending on the properties desired for a given application, the system could be tuned by adjusting the mixture. For a vehicle-charging road, very fast charging and discharging rates would be needed, while for powering a home “you have the whole day to charge it up,” so slower-charging material could be used, Ulm says.

      “So, it’s really a multifunctional material,” he adds. Besides its ability to store energy in the form of supercapacitors, the same kind of concrete mixture can be used as a heating system, by simply applying electricity to the carbon-laced concrete.

      Ulm sees this as “a new way of looking toward the future of concrete as part of the energy transition.”

      The research team also included postdocs Nicolas Chanut and Damian Stefaniuk at MIT’s Department of Civil and Environmental Engineering, James Weaver at the Wyss Institute, and Yunguang Zhu in MIT’s Department of Mechanical Engineering. The work was supported by the MIT Concrete Sustainability Hub, with sponsorship by the Concrete Advancement Foundation. More

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      in Energy

      3 Questions: What’s it like winning the MIT $100K Entrepreneurship Competition?

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      Solar power plays a major role in nearly every roadmap for global decarbonization. But solar panels are large, heavy, and expensive, which limits their deployment. But what if solar panels looked more like a yoga mat?

      Such a technology could be transported in a roll, carried to the top of a building, and rolled out across the roof in a matter of minutes, slashing installation costs and dramatically expanding the places where rooftop solar makes sense.

      That was the vision laid out by the MIT spinout Active Surfaces as part of the winning pitch at this year’s MIT $100K Entrepreneurship Competition, which took place May 15. The company is leveraging materials science and manufacturing innovations from labs across MIT to make ultra-thin, lightweight, and durable solar a reality.

      The $100K is one of MIT’s most visible entrepreneurship competitions, and past winners say the prize money is only part of the benefit that winning brings to a burgeoning new company. MIT News sat down with Active Surface founders Shiv Bhakta, a graduate student in MIT’s Leaders for Global Operations dual-degree program within the MIT Sloan School of Management and Department of Civil and Environmental Engineering, and Richard Swartwout SM ’18 PhD ’21, an electrical engineering and computer science graduate and former Research Laboratory of Electronics postdoc and MIT.nano innovation fellow, to learn what the last couple of months have been like since they won.

      Q: What is Active Surfaces’ solution, and what is its potential?

      Bhakta: We’re commercializing an ultrathin film, flexible solar technology. Solar is one of the most broadly distributed resources in the world, but access is limited today. It’s heavy — it weighs 50 to 60 pounds a panel — it requires large teams to move around, and the form factor can only be deployed in specific environments.

      Our approach is to develop a solar technology for the built environment. In a nutshell, we can create flexible solar panels that are as thin as paper, just as efficient as traditional panels, and at unprecedented cost floors, all while being applied to any surface. Same area, same power. That’s our motto.

      When I came to MIT, my north star was to dive deeper in my climate journey and help make the world a better, greener place. Now, as we build Active Surfaces, I’m excited to see that dream taking shape. The prospect of transforming any surface into an energy source, thereby expanding solar accessibility globally, holds the promise of significantly reducing CO2 emissions at a gigaton scale. That’s what gets me out of bed in the morning.

      Swartwout: Solar and a lot of other renewables tend to be pretty land-inefficient. Solar 1.0 is using low hanging fruit: cheap land next to easy interconnects and new buildings designed to handle the weight of current panels. But as we ramp up solar, those things will run out. We need to utilize spaces and assets better. That’s what I think solar 2.0 will be: urban PV deployments, solar that’s closer to demand, and integrated into the built environment. These next-generation use cases aren’t just a racking system in the middle of nowhere.

      We’re going after commercial roofs, which would cover most [building] energy demand. Something like 80-90 percent of building electricity demands in the space can be met by rooftop solar.

      The goal is to do the manufacturing in-house. We use roll-to-roll manufacturing, so we can buy tons of equipment off the shelf, but most roll-to-roll manufacturing is made for things like labeling and tape, and not a semiconductor, so our plan is to be the core of semiconductor roll-to-roll manufacturing. There’s never been roll-to-roll semiconductor manufacturing before.

      Q: What have the last few months been like since you won the $100K competition?

      Bhakta: After winning the $100K, we’ve gotten a lot of inbound contact from MIT alumni. I think that’s my favorite part about the MIT community — people stay connected. They’ve been congratulating us, asking to chat, looking to partner, deploy, and invest.

      We’ve also gotten contacted by previous $100K competition winners and other startups that have spun out of MIT that are a year or two or three ahead of us in terms of development. There are a lot of startup scaling challenges that other startup founders are best equipped to answer, and it’s been huge to get guidance from them.

      We’ve also gotten into top accelerators like Cleantech Open, Venture For Climatetech, and ACCEL at Greentown Labs. We also onboarded two rockstar MIT Sloan interns for the summer. Now we’re getting to the product-development phase, building relationships with potential pilot partners, and scaling up the area of our technology.      

      Swartwout: Winning the $100K competition was a great point of validation for the company, because the judges themselves are well known in the venture capital community as well as people who have been in the startup ecosystem for a long time, so that has really propelled us forward. Ideally, we’ll be getting more MIT alumni to join us to fulfill this mission.

      Q: What are your plans for the next year or so?

      Swartwout: We’re planning on leveraging open-access facilities like those at MIT.nano and the University of Massachusetts Amherst. We’re pretty focused now on scaling size. Out of the lab, [the technology] is a 4-inch by 4-inch solar module, and the goal is to get up to something that’s relevant for the industry to offset electricity for building owners and generate electricity for the grid at a reasonable cost.

      Bhakta: In the next year, through those open-access facilities, the goal is to go from 100-millimeter width to 300-millimeter width and a very long length using a roll-to-roll manufacturing process. That means getting through the engineering challenges of scaling technology and fine tuning the performance.

      When we’re ready to deliver a pilotable product, it’s my job to have customers lined up ready to demonstrate this works on their buildings, sign longer term contracts to get early revenue, and have the support we need to demonstrate this at scale. That’s the goal. More

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      in Energy

      Addressing food insecurity in arid regions with an open-source evaporative cooling chamber design

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      Anyone who has ever perspired on a hot summer day understands the principle — and critical value — of evaporative cooling. Our bodies produce droplets of sweat when we overheat, and with a dry breeze or nearby fan those droplets will evaporate, absorbing heat in the process creating a welcome cool feeling.

      That same scientific principle, known as evaporative cooling, can be a game-changer for preserving fruits and vegetables grown on smallholder farms, where the wilting dry heat can quickly degrade freshly harvested produce. If those just-picked red peppers and leafy greens are not consumed in short order, or quickly transferred to cold — or at least cool — storage, much of it can go to waste.

      Now, MIT Professor Leon Glicksman of the Building Technology Program within the Department of Architecture, and Research Engineer Eric Verploegen of MIT D-Lab have released their open-source design for a forced-air evaporative cooling chamber that can be built in a used shipping container and powered by either grid electricity or built-in solar panels. With a capacity of 168 produce crates, the chamber offers great promise for smallholder farmers in hot, dry climates who need an affordable method for quickly bringing down the temperature of freshly harvested fruit and vegetables to ensure they stay fresh.

      “Delicate fruits and vegetables are most vulnerable to spoilage if they are picked during the day,” says Verploegen, a longtime proponent of using evaporative cooling to reduce post-harvest waste. “And if refrigerated cold rooms aren’t feasible or affordable,” he continues, “evaporative cooling can make a big difference for farmers and the communities they feed.”

      Verploegen has made evaporative cooling the focus of his work since 2016, initially focusing on small-scale evaporative cooling “Zeer” pots, typically with a capacity between 10 and 100 liters and great for household use, as well as larger double-brick-walled chambers known as zero-energy cooling chambers or ZECCs, which can store between six and 16 vegetable crates at a time. These designs rely on passive airflow. The newly released design for the forced-air evaporative cooling chamber is differentiated from these two more modest designs by the active airflow system, as well as by significantly larger capacity.

      In 2019, Verploegen turned his attention to the idea of building a larger evaporative cooling room and joined forces with Glicksman to explore using forced, instead of passive, airflow to cool fruit and vegetables. After studying existing cold storage options and conducting user research with farmers in Kenya, they came up with the idea to use active evaporative cooling with a used shipping container as the structure of the chamber. As the Covid-19 pandemic was ramping up in 2020, they procured a used 10-foot shipping container, installed it in the courtyard area outside D-Lab near Village Street, and went to work on a prototype of the forced-air evaporative cooling chamber.

      Here’s how it works: Industrial fans draw hot, dry air into the chamber, which is passed through a porous wet pad. The resulting cool and humid air is then forced through the crates of fruits and vegetables stored inside the chamber. The air is then directed through the raised floor and to a channel between the insulation and the exterior container wall, where it flows to the exhaust holes near the top of the side walls.

      Leon Glicksman, a professor of building technology and mechanical engineering, drew on his previous research in natural ventilation and airflow in buildings to come up with the vertical forced-air design pattern for the chamber. “The key to the design is the close control of the airflow strength, and its direction,” he says. “The strength of the airflow passing directly through the crates of fruits and vegetables, and the airflow pathway itself, are what makes this system work so well. The design promotes rapid cooling of a harvest taken directly from the field.”

      In addition to the novel and effective airflow system, the forced-air evaporative cooling chamber represents so much of what D-Lab is known for in its work in low-resourced and off-grid communities: developing low-cost and low-carbon-footprint technologies with partners. Evaporative cooling is no different. Whether connected to the electrical grid or run from solar panels, the forced-air chamber consumes one-quarter the power of refrigerated cold rooms. And, as the chamber is designed to be built in a used shipping container — ubiquitous the world over — the project is a great example of up-cycling.

      Piloting the design

      As with earlier investigations, Verploegen, Glicksman, and their colleagues have worked closely with farmers and community members. For the forced-air system, the team engaged with community partners who are living the need for better cooling and storage conditions for their produce in the climate conditions where evaporative cooling works best. Two partners, one in Kenya and one in India, each built a pilot chamber, testing and informing the process alongside the work being done at MIT.

      In Kenya, where smallholder farms produce 63 percent of total food consumed and over 50 percent of smallholder produce is lost post-harvest, they worked with Solar Freeze, a cold storage company located in in Kibwezi, Kenya. Solar Freeze, whose founder Dysmus Kisilu was a 2019 MIT D-Lab Scale-Ups Fellow, built an off-grid forced-air evaporative cooling chamber at a produce market between Nairobi and Mombasa at a cost of $15,000, powered by solar photovoltaic panels. “The chamber is offering a safety net against huge post-harvest losses previously experienced by local smallholder farmers,” comments Peter Mumo, an entrepreneur and local politician who oversaw the construction of the Solar Freeze chamber in Makuni County, Kenya.

      As much as 30 percent of fruits and vegetables produced in India are wasted each year due to insufficient cold storage capacity, lack of cold storage close to farms, poor transportation infrastructure, and other gaps in the cold chain. Although the climate varies across the subcontinent, the hot desert climate there, such as in Bhuj where the Hunnarshala Foundation is headquartered, is perfect for evaporative cooling. Hunnarshala signed on to build an on-grid system for $8,100, which they located at an organic farm near Bhuj. “We have really encouraging results,” says Mahavir Acharya, executive director of Hunnarshala Foundation. “In peak summer, when the temperature is 42 [Celsius] we are able to get to 26 degrees [Celsius] inside and 95 percent humidity, which is really good conditions for vegetables to remain fresh for three, four, five, six days. In winter we tested [and saw temperatures reduced from] 35 degrees to 24 degrees [Celsius], and for seven days the quality was quite good.”

      Getting the word out

      With the concept validated and pilots well established, the next step is spreading the word.

      “We’re continuing to test and optimize the system, both in Kenya and India, as well as our test chambers here at MIT,” says Verploegen. “We will continue piloting with users and deploying with farmers and vendors, gathering data on the thermal performance, the shelf life of fruits and vegetables in the chamber, and how using the technology impacts the users. And, we’re also looking to engage with cold storage providers who might want to build this or others in the horticulture value chain such as farmer cooperatives, individual farmers, and local governments.”

      To reach the widest number of potential users, Verploegen and the team chose not to pursue a patent and instead set up a website to disseminate the open-source design with detailed guidance on how to build a forced-air evaporative cooling chamber. In addition to the extensive printed documentation, well-illustrated with detailed CAD drawings and video, the team has created instructional videos.

      As co-principal investigator in the early stages of the project, MIT professor of mechanical engineering Dan Frey contributed to the market research phase of the project and the initial conception of chamber design. “These forced-air evaporative cooling chambers have great potential, and the open-source approach is an excellent choice for this project,” says Frey. “The design’s release is a significant milestone on the path to positive impacts.”

      The forced-air evaporative cooling chamber research and design have been supported by the Abdul Latif Jameel Water and Food Systems Lab through an India Grant, Seed Grant, and a Solutions Grant. More