A laser-like focus.
That’s the distinguishing feature of the solar thermal dish, a constellation of photovoltaic mirrors on the edge of UNLV’s campus that tracks the sun’s position and precisely focuses its light onto a solar receiver.
Zealous concentration – to schoolwork, research, internships, and even hobbies – is also a quality innate to Gustavo Moreno. The UNLV Engineering first-generation student, who, alongside research engineers at the UNLV Center for Energy Research (CER), is exploring new systems of power generation with the harnessed sunlight.
“If you’re dedicated, your hard work will pay off,” said Aaron Sahm, CER research engineer. “I think Gustavo is the ultimate example of that.”
A 2018 “Star Graduate” profile from the Clark County School District affirms that his traits of “hard work and determination” set him on a course for success as early as his high school career at Moapa Valley. He re-took one of his freshman-level courses in his senior year, just to bump up his previous A- to a full A, earning a 4.1 GPA overall.
“I really value learning something new every day, in and out of school,” Moreno was quoted as saying in 2018. And it’s almost exactly what he shared as he explained one of his projects at the CER, where he’s worked as an intern for just over a year.
“I push myself and set goals to learn something new every day so that I can become a better version of myself,” he said recently. “That’s why in high school, when people would ask me what my favorite subject was, I would respond, ‘all of the above.' It’s nice to learn a little bit of math, science, English, everything.”
Moreno is the youngest of six children and grew up in Moapa, a small town about 60 miles northeast of UNLV’s campus. He is the first in his family to attend a four-year university, and is just one year shy of being the first to earn a bachelor’s degree. A feat that Matilde Moreno — Gustavo’s father who recently passed away after a battle with cancer — was shy about praising father-to-son, but would proclaim elsewhere.
“In Hispanic culture, dads don’t usually come up to their kid and say, ‘I’m really proud of you,’ but he would always tell everyone else,” Gustavo Moreno said. “I know because everyone else would tell me, ‘Oh, Dad said this about you. He’s really proud of you. He wishes he would be here to see you graduate and get married.’”
Commuting about an hour and 20 minutes each day, Moreno has attended UNLV for the past three years. And like the CER where he works almost daily, this mechanical engineering junior has his hands in a lot of projects.
One moment, he’s at the northern end of the state, working with a team of fellow UNLV engineering students to launch a scientific balloon carrying a payload of experiments during a solar eclipse; the next, he’s in Moapa, the “fixer” for all mechanical issues that go awry at home, where he lives with his mom.
“I do a lot of things with my hands,” Moreno said. Whether I’m doing maintenance or fixing cars, being a plumber for a day; building, making things. I have a passion for woodcraft, too.”
But his internship at the CER — in addition to the heavy load of engineering coursework — takes up a majority of his attention.
Internship With Impact
The CER is in the midst of a two-year, $400,000 project funded by the Department of Energy (DOE). They've reached phase 2 of a research collaboration into how supercritical CO2, the supercritical fluid state of carbon dioxide, can be used — instead of water — as the working fluid in a power cycle. That has potential to lower the cost and increase the efficiency of the power cycle. When a chemical compound, like CO2, is in its supercritical state, it can adopt properties midway between a gas and a liquid, expanding to fill a container like a gas, but exhibiting a density more common to liquids.
Unlike coal-fired power plants that use the Rankine cycle — heated water makes steam that then turns a turbine — the CER is building a system called the Brayton cycle that receives heat from the high concentrated solar power dish, which then expands the carbon dioxide gas in order to spin the turbine. As the gas leaves the turbine, its heat is recovered in a heat exchanger. The heat that can’t be recovered is ejected into the air.
Rick Hurt, a CER research engineer, said, “Developing a system that doesn’t use water is really important in the desert Southwest and in drought conditions." He added that about 48% of water used in the U.S. is used to generate electricity. He also added that the turbomachinery needed for supercritical CO2 cycles is orders of magnitude smaller than comparable systems.
It’s being considered for use in nuclear power plants, but the CER is more interested in smaller-scale applications, such as being able to generate power at a remote military site, as opposed to needing to haul in huge diesel generators and fuel.
Phase 2 is exploring ways to get power out of the turbine, and harness it for electricity generation.
“One of the problems with supercritical CO2 is that because the pressure is so high that the fluid is operating at, how do you connect something to it? How do you connect an induction motor to get that rotating motion and generate electricity with it?” Sahm said, adding that because of small scale of the turbine, it wants to spin at speeds 10 times higher than the connecting motor.
One possible answer: magnets.
“Using a magnet, we can transmit the magnetism through the pressure wall, and then there’s no seal, there’s no place for it to leak CO2,” said Hurt. “So it’s high-temperature, high-pressure CO2 on one side, ambient air on the other side. That’s how we can take the rotational energy of the supercritical CO2 turbine, and power an induction motor generator on the outside.”
The magnetic coupling system has another added benefit, Moreno added: it’s practically maintenance free.
“We don’t have to have a shaft going through the pressure wall, which would require a complicated seal,” Moreno said. “We won’t need to lubricate it because there are no gears involved. The magnets are doing all the work and the magnetic flux density is transferring the energy.”
Moreno, Sahm, and Hurt are still in the multiphysics modeling stage of the project — and more broadly, the U.S. is probably years away from a large-scale application of the technology — but, if it works, their findings could have implications for future power generation.
“We have monthly meetings with DOD (Department of Defense) and DOE,” Hurt said. “They’re excited about this.”
The ‘Multi-potential’ of an Engineering Career
For Moreno, the tangible benefits of the research are likely to come much sooner. The internship has opened his eyes to the job opportunities available to mechanical engineers in the solar energy industry.
“I never had any clue that there were solar jobs out there that could be a good place to start,” he said, adding that prior to his time at the CER, Moreno was pretty focused on automotive engineering.
But, if his side hobby — fixing up his 2003 GMC Sierra 1500 pickup truck — is any indication, cars might still have his heart.
“Multi-potential — that’s the word I would use to best describe myself,” he said.