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HTMLText_33711F51_3D9B_3042_41C8_5BBC76E1A7A1.html = Microsystems and Engineering Sciences Applications (MESA)
Welcome to MESA, home of Sandia’s advanced nuclear weapons research, design and development functions, as well as integrated materials research, and the production facilities for microsystem technologies.
Focused primarily on the nuclear weapons mission, the facilities that make up MESA ultimately connect with all of Sandia's mission areas via microsystems research and applications.
After eight years of construction, MESA was completed in 2007 at a cost of $518 million. It was Sandia's largest construction project since the Labs' first permanent buildings were built in the 1940s.
898 Lobby
Building 898 is a three-story, partially pre-fabricated, facility housing offices and light laboratories. Designed as an integrated facility promoting interaction among groups via workspace blocks, the building sports a postmodern, high-tech industrial design. The soaring lobby and high ceilings create an open and empowering environment for the design work housed here.
Gowning Room
Clean rooms environments are kept clean both by limiting the volume of particles introduced to the space and by constantly moving the air to remove particles. Workers wear protective garments to reduce the number of contaminants they introduce to the room. This changing station allows staff to put on appropriate layers prior to entering a clean room; additional changing rooms allow for full changes of clothing.
858 Lobby
Originally built in the late 1980s to house the Manufacturing Development Laboratory and its offices, Building 858 expanded significantly when 858EF (the MicroFab) and 858EL (MicroLab) were added as part of the MESA construction. The building houses wafer manufacturing, compound semiconductor fabrication, microelectromechanical systems (MEMS) production, and electronic circuit manufacturing.
MicroFab
The MESA Microsystems Fabrication facility is one of the most complex buildings at Sandia. It is the first in the world to combine silicon processing with fabrication of compound semiconductors under one roof. This is the heart of microsystem manufacturing, done primarily in cleanrooms.
858 SiliconFab
Building 898 is a three-story, partially pre-fabricated, facility housing offices and light laboratories. Designed as an integrated facility promoting interaction among groups via workspace blocks, the building sports a postmodern, high-tech industrial design. Its polished stone and steel and glass exterior includes curvilinear walled ribbons of windows leading to the northeast entrance, and extended wings with sun-protecting louvered windows. The soaring lobby and high ceilings create an open and empowering environment for the design work housed here.
898 Corridor
State-of-the-art videoconferencing and stunning projection capabilities make the VIEWS Corridor a prime viewing and sharing spot for scientific computing displays. Output from the visualization tools used in Sandia's high performance computing arena can be projected in 3D. The area is a magnet for VIP visits and tours.
858 Photolith Lab
Sandia maintains a clean room outside of the MicroFab area for its photolithography processes. This allows the MESA workers to develop and maintain customized processes without disruption to the manufacturing effort.
Most solar tower arrays aren’t built for experimentation, but to generate electricity. However, even though Sandia’s solar facility focuses on science and discovery, it could work like a standard Concentrating Solar Power plant. There is a steam turbine in the tower, though it isn’t functional anymore. Part of the reason it isn’t used anymore is it’s pretty expensive to generate electricity every day; there needed to be someone in the control tower, someone out in the field to make sure the generator worked right, and someone to operate the power block. The logistics of all of that were cost prohibitive, thus the Solar Tower was quickly designated a research facility. The generator is still located in the tower.
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The mirrors in this heliostat field are beautiful, but they can also be dangerous. Looking at their reflection of the Sun even briefly can cause blindness. The reflections can also be problematic for airplanes passing over head. The real danger is in the focal length, or the distance from the center to the focal points. That’s the point where the energy is fully concentrated, and thus the most dangerous. Outside of that point, things might be a bit warmer and uncomfortable, but not immediately life threatening. For safety purposes, heliostats are pointed at the ground when not in use, and an exclusion zone exists to the East; no one is allowed in that zone as the heliostats are moved into position.
In a falling particle receiver, these ceramic sand-like particles fall from a hopper at the top of the receiver tower. As they pass the focused solar energy from the heliostat array, they heat up and fall into a collection tank. The hot particles are then released into another tank as energy is needed for power generation. Used thermal-storage particles, which are now much cooler, are then released into the lower tank where an elevator with a scoop returns them to the top of the tower to start the process over.
The goal of this experiment is to reach greater than 90% thermal efficiency and particle temperatures of at least 700° C. The hotter the temperature, the more energy that is available and the cheaper it is to store it. Finding a way to cheaply and efficiently store thermal energy directly, such as in these heated particles, will help solar plants to produce power at night and even on cloudy days.
Test and data acquisition can be managed from the Control Room, but for tests that require more up close and personal attention, there’s this little shed at the top of the tower. It houses its own set of data acquisition and processing equipment, and also houses infrared cameras. The shed serves another, more practical function; it provides protection for observers when tests are being conducted, without requiring them to retreat all the way back to the Control Tower.
The Bob Edgar Solar Furnace first came online back in 1982. It was initially installed to calibrate solar instrumentation for the Central Receiver Test Facility (the Solar Tower). It wasn’t really named after Bob Edgar, but he did have responsibility for the new function, which achieved temperatures up to 5000 degrees.
From this control center, the amount of energy from the Sun that actually enters the furnace can be precisely regulated. The angle of the heliostat and the degree to which the attenuators are open are both controlled from here. This is also where the data from the numerous sensors and cameras are collected, not to mention that this is really the only safe place to be when the furnace is operating.
No, your eyes do not deceive you, that is aluminum foil; the same stuff you use to cover a baking dish in your oven at home. Here, aluminum foil is used to protect the pyrometers from incident radiation and from the extreme temperatures. If there’s convection on the outside of the sensors, the temperature measurements can be way off, especially if radiation is coming from the stage during a test. Hence, that handy aluminum foil, which turns out has more uses than covering your casserole.
The Solar Tower is 200 feet tall, with an elevator that extends down 30 more feet, and a foundation that extends even deeper into the ground. The hole for the Solar Tower’s foundation was so deep it took a continuous line of cement trucks 14 hours to pour an endless flow of concrete for the foundation.
These slats are called attenuators. They control the amount of light from the sun that’s allowed into the solar furnace; anywhere from zero to 100%. They flap up and down, not unlike mini-blinds, only on a much larger scale. Sunlight is reflected off a heliostat behind the attenuators onto the mirror inside the furnace building, which narrowly focuses that energy onto a stage where samples are placed for testing. Warning: Don’t get in the way, even SPF1000 sunscreen won’t be enough to protect from sun burn—or worse—when the furnace is being used.
As the solar furnace doors open, the immense, mirrored dish looms, almost making one want to break out into a super-villain laugh of evil: “Behold the power of this fully operational Solar Furnace!” Bwahahahahahaha!
The 260 foot test level is an open style test level that is exposed to the outdoors. It can accommodate large test articles and achieve high flux levels during testing, reaching temperatures equivalent up to 2,000 suns. In the past, this level has housed static test articles for exposure to high thermal flux.
Construction of the Solar Tower used a method known as “slip forming.” The form at the top of the tower was constructed first, and then it was jacked up for each successive concrete pour. Essentially, the top of the tower was built first and the rest of the tower was built beneath it. Watch how the top of the tower seems to rise from the desert in this fascinating time lapse from the tower’s construction.
The Solar Furnace isn’t just for testing terrestrial materials, it can also help test materials for space. This facility can test items either at high pressures, up to 100 psi, or down to a near vacuum, using either compressed or inert air. That atmosphere can then be heated up by the furnace in order to test environmental dependencies for sample materials, thus helping to determine if those materials are suitable for extreme environments, such as the final frontier.
There are only two solar furnace test facilities like this in the world, one in Spain and one here. The one in Spain is getting ready to shut down, which means this facility will soon be one of a kind.
The shutters on the attenuator can open and close quite quickly, making it easy to shine the light on a test object, or not, in a matter of seconds.
The biggest tests at the solar tower go right to the top…of the tower. For example, Sandia tested the prototype falling particle receiving system here. The system examined whether ceramic particles could be a solution for storing energy cheaply (as opposed to storing energy in batteries, which can be expensive). The particles drop through receiver, flux (watts per meter squared) comes into the receiver from the heliostat field and the particles absorb the thermal energy. They then fall into a hopper and are diverted to either be reheated or into a thermal storage container. The heat is transferred through a heat exchanger to a heat transfer flow to generate electricity.
The system seen here is prepping to do measurements for thermal efficiencies, that is, a measure of the amount of heat supplied to the system compared to the amount of heat rejected by the system. This particle receiver has recorded thermal efficiencies of up to 80%.
This facility has the capability to test at much higher energy levels than at the tower and heliostat field. The amount of flux; or the amount of incident energy per meter squared, is about 6,000 Suns; or 500 Watts per centimeter squared. The general large solar field maxes out at around 2,800 Suns. Why the big difference? It all has to do with scale.
The tower uses the field to create and focus a beam that’s around one meter in diameter. At the solar furnace, the spot is only around five centimeters, giving it a much higher concentration. Typically, initial tests on materials are done at this facility before moving to larger scale testing on the tower. Testing is done here just about every day; it’s easy to set up and less costly than using the field. Sometimes the customers only want to test here because it’s cost effective, and with some test materials, scale doesn’t matter as much; testing a small sample is just as effective as testing a large sample would be.
Beneath the tower, under the field of mirrors, there is darkness … that is, there’s a really dark tunnel that runs from the tower to the control facility. The tunnel’s main function is to run cables between the tower and the Control Room. However, it also provides access to the facility during inclement weather and can be used as a safe way to escape the tower during dangers such as lightning.
Only the biggest tests got to the top. That is, the top of the tower is used for testing large items. It has two characterization/test stands, such as this one, that can be oriented to the heliostat field for direct exposure testing. Flux levels up to 2,500 Suns have been achieved. Sample size can be 3 ft. x 5 ft. or bigger depending on how much heating is required on the samples.
This console is used for data processing. There’s also a camera on this side; its feed shows up in the center console and is a tool for the beam characterization system. When the heliostat flux is put on the target, this system can produce an image of the flux on the target to see what the flux distribution looks like. When a sample is in a fixture, it’s important to make sure the flux profile is properly centered. The camera helps test controllers move the spot created by the heliostat field so it will correctly match the flux profile being tested.
The different panels—or individual mirrors—on the dish are called facets. To produce the intense energy needed for testing, each facet has a certain amount of pressure placed on its corners to make it concave. This process is called canting. Each individual corner of each facet has to be canted precisely long before a heliostat (such as this one) is placed in the field. The process is done on a smaller scale at the Optical Lab.
It only takes about ten minutes to align all the mirrors for a test, and once they are, they focus reflected sunlight into a concentrated point that can be the equivalent 400 Suns. This piece of aluminum was melted in just 23 seconds by using around half of the heliostats in the field. Imagine how quickly it could cook your s’mores!
The Solar Tower facility covers 117 acres. The heliostat field takes up eight of those acres, which may look and sound pretty big, but for this type of facility, it’s actually small. Because this is a test facility, it’s much smaller in scale than a commercial facility. Most Concentrating Solar Power plants use between 370 acres and 790 acres; much of it used by the heliostat field that surrounds the tower in every direction. Sandia’s Solar Tower field is located only on the north side of the tower.
They look flat, don’t they? But they aren’t. Mirrors in a heliostat field such as this need to be concentrators. To do that they need to be a very precise parabolic shape (or a u-shaped curve with specific properties). If a mirror is flat, it can’t concentrate the Sun’s power; instead, it just reflects it back. With the proper curvature, the entire heliostat can focus its energy on a smaller spot. In an actual power generating system, refinements are controlled by robots, which precisely give each heliostat the right curvature to effectively concentrate the Sun’s power. This is especially important for operating Concentrating Solar Plants as the heliostats may be up to a mile away from the tower. Accuracy in the canting or tilting of the mirrors is vital to efficiently produce power.
In the vastness of the New Mexican high mesa desert, it can be hard to appreciate the scale of the National Solar Thermal Test Facility, or as it’s more commonly known, the Solar Tower. Against the back drop of the Sandia Mountains, the tower may not look it, but it’s actually 200 feet tall, and extends another 100 feet under the ground. Within the tower there are three test bays, and tests can also be performed on the very top of the tower. A huge, three-story elevator lifts items weighing up to 100 tons to the top.
The 240 level (so named because it is 140 feet above ground level) is the middle test level at the Solar Tower. This level is a unique facility with an integrated wind tunnel that can provide forced convection cooling at 0.3 Mach across test samples exposed to high flux conditions (up to 1,200 kW/m2). The facility has a high-speed shutter to expose samples with a 0.5 second ramp and decay rate producing a pseudo-square flux impulse profile. It has a calibration panel for measuring power input on a sample, data acquisition and instrumentation capabilities, cooling water (up to 1 MWth), and pressurized air. This test level has been used to test experimental material samples and hardware under extreme conditions, such as high heat combined with high wind, so pretty much like a typical New Mexico afternoon.
The lowest test level at the solar tower is at 220 ft. This level has a large opening to accommodate larger test articles and is capable of exposing samples to heat fluxes as high as 2,000 kW/m2. It has a calibration panel for measuring power input on a sample, data acquisition and instrumentation capabilities, cooling water (up to 1 MWth), and pressurized air. This test level has been used to test experimental receivers, including a recent LDRD funded project looking at the geometry of the receiver tubes on optical efficiency.
200 feet is pretty high, but to truly appreciate just how tall this tower is, nothing compares to being inside and then staring into the black abyss, wwwwwaaaayyyy down at the bottom. Warning: this video probably isn’t for those with issues with heights or vertigo.
Moving 100 tons of equipment up 200 feet is no easy feat, and certainly not something to be done quickly. It takes a full working day, or eight hours, for the elevator to make its way to the top. Coming down, it takes 10 hours; after all, one wouldn’t want 100 tons of equipment to descend too quickly. As the elevator comes to the ground floor, it actually extends down 30 feet into the ground.
The Solar Tower does some big experiments, and it has a big elevator to get those experiments to the top of the big tower, so it only makes sense it would have a big door to wheel those experiments through. This massive door is 60 feet high, but don’t worry, King Kong rarely makes a visit here.
The stage is the platform where samples and materials are placed for testing. The stage is covered with several gauges and sensors for data collection. It has flux gauges as well as a range of pressure, temperature, and flow sensors for measurements. There is also a camera mount giving the facility the ability to conduct high-speed photography, along with infrared (IR) cameras to look at the IR spectrum. In the middle of the dish there are more high-speed photography cameras, along with temperature pyrometers, regular cameras, and IR cameras.
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This contraption is used to raise up test items to expose them to flux from the Heliostat Field. Smaller items, such as the Christmas tree shown in the video, are raised up and have the Sun’s energy focused on them for just a few seconds before things really get scorching. One of the goals of these tests is to determine how large materials respond at extreme heat flux conditions and to identify differences in ignition conditions for different materials.
Much like in the center of the dish, there are sensors and cameras located throughout the facility to better capture readings from IR sensors to video from a vast array of high-speed and real-time cameras. In essence, an experiment can be monitored and recorded from a whole array of angles, providing a huge amount of useful data.
Much like Benjamin Franklin’s legendary kite and key, these spikes are used to attract lightning. They provide lightning grounding and isolation, essentially diverting lightning away from other critical gear on the high solar tower. In 2004, there were tests done with a bigger pole right next to the tower that was intended to attract direct lightning strikes to explore how to redirect them. The current spikes around the top of the tower are for safety, not research.
The line in the middle of the photo marks the shutter system, in which two doors open and close in less than a second, just long enough to heat something up. The system is used to do a lot of modeling and materials testing; for example, the high insulation RSLE board can take over a 1000 degrees Celsius of heat.
Not every test takes place up here on the top of the tower. Some tests need to be done on a smaller scale. That’s why the Solar Tower complex also has facilities like the Robotic Testing Facility. Here, a robot assists with small-scale material testing by exposing small samples (called coupons) to intense heat.
Almost every year, Sandia hosts Take Your Sons and Daughters to Work Day. What’s the best way to demonstrate the awesome power of the solar furnace to a bunch of kids? By burning stuff, of course. For instance, researchers can set up a demo that burns a hole through a brick, turning it to glass as it does so. The kids may not remember all the science, but they won’t forget the burnt brick with a hole in it. Or making cookies with a solar oven, but keep a close eye on those; kids don’t like sun-burnt cookies.
To make sure the incoming flux (watts per meter squared) from the heliostat field is properly focused, this calibration panel is used before testing commences. The panel measures the amount of incident energy the heliostats are producing and makes sure it’s at the proper level for testing. The calibration process can produce incident energy so intense that a cooling system is needed to keep the calibration unit from overheating. The cooling system uses a refrigerant similar to what is used in your car for the A/C. After the calibration is made, a target can be set in place for testing. Targets have ranged from trees for the forest service to tiles for the space shuttle for NASA and various items for the military.
The solar furnace only uses one heliostat that’s 95 m2, and one reflective dish that measures 6.8 m in diameter. That’s big enough to produce 16 kW of total thermal power, and a peak flux of 500 W/cm2. That’s plenty of power for investigating the thermophysical properties of materials when exposed to concentrated sunlight. It’s also enough power to simulate the thermal effects of a nuclear explosion.
A quick glance out this window reveals a couple of impressive dishes. The dishes are similar to the ones used at the Very Large Array in Socorro, New Mexico, and while they weren’t really meant to be used this way, at one point, mirrors were going to be placed on the surface to see if it was possible to get them to behave as dish reflectors. The intent was to set up a solar furnace arrangement, hence the attenuator sitting near where a heliostat was potentially going to be placed. A dish concentrator was set up, but the effort never went anywhere. For now, this area awaits future possibilities for how it might further the research being done at the Solar Tower.
There are 212 working heliostats in the field with 25 mirrors each. How do researchers keep more than 5300 mirrors clean? Let nature do the work. Both rain and snow keep the mirrors clean, with snow being more effective because it slides off the mirrors as it melts. This is good, because keeping those mirrors clean would require a huge Windex® budget. Nature is cheaper, and just as effective.
This field of mirrors is known as the Central Receiver Test Facility. The 212 heliostats can direct up to 6 megawatts of solar thermal energy on to the tower and test object. If this facility were to generate power, it could produce around 1 megawatt of electricity, or about enough to power 500 homes on a bright sunny day.
In order to take full advantage of the best time to catch and focus the sun’s rays, testing takes place in a fairly narrow window within plus or minus an hour of solar noon. Solar noon is when the sun is highest in the sky. During day light savings that’s around 1 p.m., the rest of the year the window starts at noon, Mountain Standard Time.
A standard day in the control room consists of setting up and executing tests while working with partners and customers to collect and analyze the data. The test director/operator orients the heliostats for the test, and then explains to the team what the process and steps will be. They also interact with customers on the testing and the data being collected. Typically, there is a lot of repetitiveness to the testing as it mostly consists of putting heat on and off something. Customers can observe testing from the control room, and the site is set up on its own local network—not connected to any Sandia network—so customers can pull data as the test is happening.
There aren’t a lot of trees in the desert plains of New Mexico, so where is a bird to nest? On occasion, they choose one of the tallest structures around: the Solar Tower. In the past, owls have made the tower their home, which presents a unique set of challenges because their nests can’t be moved, at least not legally.
When the details of the Central Receiver Test Facility were presented in 1975, there wasn’t another facility like it in the world. This original concept facility began construction 1976 and was completed in 1978. In 1984, a new Distributed Receiver Test Facility was added in a space near the tower. Additional experiments and test bed technology were added over the ensuing years, and the overall facility continues to evolve.
In July 2018, the Solar Tower celebrated 40 years of research and scientific advancement as a unique facility for energy R&D. As a part of the festivities, participants helped recreate a photo from the tower’s opening forty years before.
During a visit to the Solar Tower, you may notice these yellow barrels sitting around. Unlike their cousins, the infamous orange barrels of road construction, these barrels don’t mark construction zones, but rather where other heliostats were to be placed and could still potentially be placed in the future. All the heliostats are on the north side of the tower, but there are some of these barrels on the south side, reflecting earlier considerations of implementing a more traditional Concentrating Solar Power plant, which would typically have heliostats on all sides.
Up on the roof there isn’t a chimney for Santa, but there is a bunch of solar instruments. One helps track the Sun using a two-axis gear system so it can stay fixed on the Sun throughout the day and provide precise information on its location. There are also several video cameras; one focused on the tower, and three more point in each direction of the compass, thus the tower is provided visuals in 360 degrees.
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This is where the entire field is controlled. The heliostats can be precisely positioned to focus energy on any of the three levels of the tower, or at the testing platform at the top.
It doesn’t take long to get these mirrors to snap to attention; usually it’s 10 minutes or less and they’re aligned and ready to shine. It’s a beautifully choreographed display of movement with a powerful conclusion (quite literally, since the end result is focusing the power of the Sun).
A heliostat is an instrument consisting of a panel of mirrors that is moved to reflect the Sun’s rays in a fixed direction. In the case of this facility, a heliostat consists of a panel of 25 mirrors laid out in a grid, all properly aligned to concentrate the Sun’s energy on a fixed point.
Each heliostat (or you can just call them mirrors if you want, though that’s a bit of a misnomer) is a composite structure. The glass on top protects the reflective surface. The reflective surface is a silver substrate which is highly reflective and useful for directing sunlight in the direction needed for conducting experiments. Finally, the back of each panel has glass with copper backing. The copper backing helps reflect any light that happens to go through the silver substrate so as much energy as possible is captured.
These switches look impressive, and complicated, but they serve a very simple yet critical function. They are failsafe switches, meaning if the heliostats are doing something weird, like suddenly spinning around for no reason, they can be shut down and put in a known position as a safety measure. A quick flick of a switch prevents a heliostat from doing something it shouldn’t and protects workers who may be in the field.
When the Solar Tower was first built in 1977, not only was it a one-of-a-kind facility, but its full potential and capabilities still had a long way to go before being fully realized. Take a trip back in time to see how it all got started with this video.
The Control Room is the central nervous system of the Solar Tower facility, and everything from the heliostats to the test bays in the tower itself are controlled from here. The heliostats can be controlled individually or as an entire field from this room, depending on how much flux needs to be focused on the tower.
The center console is the data acquisition program. This system collects real-time data during a test. It also records the data so it can be analyzed later. This station has a collection of voltage inputs that measure how hot a sample is getting during a test. The shutter system for the 240 test bay is also controlled from here.
Among the other facilities on the grounds of the Solar tower is the dish testing facility. This area allows other companies and industry partners to set up systems for long-term reliability testing and evaluation. There are currently 16 dishes being tested in this area, along with two Sandia-developed solar dishes used for research purposes.