Environment

As an undergraduate majoring in architecture, Dong Nyung Lee ’21 wasn’t sure how to respond when friends asked him what the study of architecture was about.“I was always confused about how to describe it myself,” he says with a laugh. “I would tell them that it wasn’t just about a building, or a city, or a community. It’s a balance across different scales, and it has to touch everything all at once.”As a graduate student enrolled in a design studio course last spring — 4.154 (Territory as Interior) — Lee and his classmates had to design a building that would serve a specific community in a specific location. The course, says Lee, gave him clarity as to “what architecture is all about.”Designed by Roi Salgueiro Barrio, a lecturer in the MIT School of Architecture and Planning’s Department of Architecture, the coursework combines ecological principles, architectural design, urban economics, and social considerations to address real-world problems in marginalized or degraded areas.“When we build, we always impact economies, mostly by the different types of technologies we use and their dependence on different types of labor and materials,” says Salgueiro Barrio. “The intention here was to think at both levels: the activities that can be accommodated, and how we can actually build something.”Research firstStudents were tasked with repurposing an abandoned fishing industry building on the Barbanza Peninsula in Galicia, Spain, and proposing a new economic activity for the building that would help regenerate the local economy. Working in groups, they researched the region’s material resources and fiscal sectors and designed detailed maps. This approach to constructing a building was new for Vincent Jackow a master’s student in architecture.“Normally in architecture, we work at the scale of one-to-100 meters,” he says. But this process allowed me to connect the dots between what the region offered and what could be built to support the economy.”The aim of revitalizing this area is also a goal of Fundación RIA (FRIA), a nonprofit think tank established by Pritzker Prize-winning architect David Chipperfield. FRIA generates research and territorial planning with the goal of long-term sustainability of the built and natural environment in the Galicia region. During their spring break in March, the students traveled to Galicia, met with Chipperfield, business owners, fishermen, and farmers, and explored a variety of sites. They also consulted with the owner of the building they were to repurpose.Returning to MIT, the students constructed nine detailed models. Master’s student Aleks Banaś says she took the studio because it required her to explore the variety of scales in an architectural project from territorial analysis to building detail, all while keeping the socio-economic aspect of design decisions in mind.“I’m interested in how architecture can support local economies,” says Banaś. “Visiting Galicia was very special because of the communities we interacted with. We were no longer looking at articles and maps of the region; we were learning about day-to-day life. A lot of people shared with us the value of their work, which is not economically feasible.”Banaś was impressed by the region’s strong maritime history and the generations of craftspeople working on timber boat-making. Inspired by the collective spirit of the region, she designed “House of Sea,” transforming the former cannery into a hub for community gathering and seafront activities. The reimagined building would accommodate a variety of functions including a boat-building workshop for the Ribeira carpenters’ association, a restaurant, and a large, covered section for local events such as the annual barnacle festival.“I wanted to demonstrate how we can create space for an alternative economy that can host and support these skills and traditions,” says Banaś. Jackow’s building — “La Nueva Cordelería,” or “New Rope Making” — was a facility using hemp to produce rope and hempcrete blocks (a construction material). The production of both “is very on-trend in the E.U.” and provides an alternative to petrochemical-based ropes for the region’s marine uses, says Jackow. The building would serve as a cultural hub, incorporating a café, worker housing, and offices. Even its very structure would also make use of the rope by joining timber with knots allowing the interior spaces to be redesigned.Lee’s building was designed to engage with the forestry and agricultural industries.“What intrigued me was that Galicia is heavily dependent on pulp production and wood harvesting,” he says. “I wanted to give value to the post-harvest residue.”Lee designed a biochar plant using some of the concrete and terra cotta blocks on site. Biochar is made by heating the harvested wood residue through pyrolysis — thermal decomposition in an environment with little oxygen. The resulting biochar would be used by farmers for soil enhancement.“The work demonstrated an understanding of the local resources and using them to benefit the revitalization of the area,” says Salgueiro Barrio, who was pleased with the results. FRIA was so impressed with the work that they held an exhibition at their gallery in Santiago de Compostela in August and September to highlight the importance of connecting academic research with the territory through student projects. Banaś interned with FRIA over the summer working on multiple projects, including the plan and design for the exhibition. The challenge here, she says, was to design an exhibition of academic work for a general audience. The final presentation included maps, drawings, and photographs by the students.For Lee, the course was more meaningful than any he has taken to date. Moving between the different scales of the project illustrated, for him, “the biggest challenge for a designer and an architect. Architecture is universal, and very specific. Keeping those dualities in focus was the biggest challenge and the most interesting part of this project. It hit at the core of what architecture is.” More

Feeling thirsty? Why not tap into the air? Even in desert conditions, there exists some level of humidity that, with the right material, can be soaked up and squeezed out to produce clean drinking water. In recent years, scientists have developed a host of promising sponge-like materials for this “atmospheric water harvesting.”But recovering the water from these materials usually requires heat — and time. Existing designs rely on heat from the sun to evaporate water from the materials and condense it into droplets. But this step can take hours or even days. Now, MIT engineers have come up with a way to quickly recover water from an atmospheric water harvesting material. Rather than wait for the sun to evaporate water out, the team uses ultrasonic waves to shake the water out.The researchers have developed an ultrasonic device that vibrates at high frequency. When a water-harvesting material, known as a “sorbent,” is placed on the device, the device emits ultrasound waves that are tuned to shake water molecules out of the sorbent. The team found that the device recovers water in minutes, versus the tens of minutes or hours required by thermal designs.

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MIT engineers design an ultrasonic system to “shake” water out of an atmospheric water harvester. The new design can recover captured water in minutes rather than hours.

Unlike heat-based designs, the device does require a power source. The team envisions that the device could be powered by a small solar cell, which could also act as a sensor to detect when the sorbent is full. It could also be programmed to automatically turn on whenever a material has harvested enough moisture to be extracted. In this way, a system could soak up and shake out water from the air over many cycles in a single day.“People have been looking for ways to harvest water from the atmosphere, which could be a big source of water particularly for desert regions and places where there is not even saltwater to desalinate,” says Svetlana Boriskina, principal research scientist in MIT’s Department of Mechanical Engineering. “Now we have a way to recover water quickly and efficiently.”Boriskina and her colleagues report on their new device in a study appearing today in the journal Nature Communications. The study’s first author is Ikra Iftekhar Shuvo, an MIT graduate student in media arts and sciences, along with Carlos Díaz-Marín, Marvin Christen, Michael Lherbette, and Christopher Liem.Precious hoursBoriskina’s group at MIT develops materials that interact with the environment in novel ways. Recently, her group explored atmospheric water harvesting (AWH), and ways that materials can be designed to efficiently absorb water from the air. The hope is that, if they can work reliably, AWH systems would be of most benefit to communities where traditional sources of drinking water — and even saltwater — are scarce.Like other groups, Boriskina’s lab had generally assumed that an AWH system in the field would absorb moisture during the night, and then use the heat from the sun during the day to naturally evaporate the water and condense it for collection.“Any material that’s very good at capturing water doesn’t want to part with that water,” Boriskina explains. “So you need to put a lot of energy and precious hours into pulling water out of the material.”She realized there could be a faster way to recover water after Ikra Shuvo joined her group. Shuvo had been working with ultrasound for wearable medical device applications. When he and Boriskina considered ideas for new projects, they realized that ultrasound could be a way to speed up the recovery step in atmospheric water harvesting.“It clicked: We have this big problem we’re trying to solve, and now Ikra seemed to have a tool that can be used to solve this problem,” Boriskina recalls.Water danceUltrasound, or ultrasonic waves, are acoustic pressure waves that travel at frequencies of over 20 kilohertz (20,000 cycles per second). Such high-frequency waves are not visible or audible to humans. And, as the team found, ultrasound vibrates at just the right frequency to shake water out of a material.“With ultrasound, we can precisely break the weak bonds between water molecules and the sites where they’re sitting,” Shuvo says. “It’s like the water is dancing with the waves, and this targeted disturbance creates momentum that releases the water molecules, and we can see them shake out in droplets.”Shuvo and Boriskina designed a new ultrasonic actuator to recover water from an atmospheric water harvesting material. The heart of the device is a flat ceramic ring that vibrates when voltage is applied. This ring is surrounded by an outer ring that is studded with tiny nozzles. Water droplets that shake out of a material can drop through the nozzle and into collection vessels attached above and below the vibrating ring.They tested the device on a previously designed atmospheric water harvesting material. Using quarter-sized samples of the material, the team first placed each sample in a humidity chamber, set to various humidity levels. Over time, the samples absorbed moisture and became saturated. The researchers then placed each sample on the ultrasonic actuator and powered it on to vibrate at ultrasonic frequencies. In all cases, the device was able to shake out enough water to dry out each sample in just a few minutes.The researchers calculate that, compared to using heat from the sun, the ultrasonic design is 45 times more efficient at extracting water from the same material.“The beauty of this device is that it’s completely complementary and can be an add-on to almost any sorbent material,” says Boriskina, who envisions a practical, household system might consist of a fast-absorbing material and an ultrasonic actuator, each about the size of a window. Once the material is saturated, the actuator would briefly turn on, powered by a solar cell, to shake out the water. The material would then be ready to harvest more water, in multiple cycles throughout a single day.“It’s all about how much water you can extract per day,” she says. “With ultrasound, we can recover water quickly, and cycle again and again. That can add up to a lot per day.”This work was supported, in part, by the MIT Abdul Latif Jameel Water and Food Systems Lab and the MIT-Israel Zuckerman STEM Fund. More