Inquiry 2016, Issue 2

Inqui r y I s sue

| 2016

Inqui r y I s sue

| 2016

B Y L A U R A M I L L S A P S

efrigeration has been such an integral part

of our everyday lives for so long that we rarely think

of it. Our food is fresh and our offices and living

rooms temperature-controlled thanks to the vapor-

compression technology developed over a century ago, and

it is an integral part of medical care, transportation, military

defense, and more.

At Ames Laboratory a new research consortium

called CaloriCool

launched in 2016 with the idea that

refrigeration could be radically better—cheaper, cleaner,

more precise and energy-efficient—by abandoning vapor-

compression for something entirely new: a solid-state caloric

system. And this research team plans to do it—including

adoption into manufactured systems and products—within

a decade.

“It’s like replacing the incandescent light bulb with an

LED bulb; the new technology does the same thing, but in a

completely different andmuchmore efficient and sustainable

way,” said Vitalij Pecharsky, director of CaloriCool. “That’s

what CaloriCool will do with the refrigeration and heat

pumping industries.”

The idea that caloric systems could be used as a

replacement for traditional refrigeration technology is actually

nothing new. For the last 20 years, materials scientists have

been searching for compounds that can generate strong

cooling effects when cyclically acted upon by magnetic,

electric, or mechanical forces—called magnetocaloric,

electrocaloric, and elastocaloric materials.

Starting with the discovery of gadolinium-silicon-

germanium compounds in Ames in 1997, a few other

materials are worth mentioning. These include lanthanum-

iron-silicon-hydrides and iron-manganese-silicon-phosphides

for magnetocalorics, nickel-titanium for electrocalorics, and

selected terpolymers for electrocalorics. But none of those

materials have been exactly right for commercialization

into any kind of product like a residential refrigerator, or

building environmental systems. “This is essentially what

CaloriCool consortium’s goal: game-changing refrigeration technology within a decade

CaloriCool is going after,” said Pecharsky, who is also an Iowa

State University Anson Marston Distinguished Professor of

Materials Science and Engineering and Ames Laboratory

faculty scientist. “We know the real obstacle preventing the

leap into marketable technology is the lack of affordable,

high-performance caloric materials.”

The search has already begun in earnest, led by a team of

researchers based in Ames and enhanced by partner teams

who represent a range of skills vital to the effort, including

theoretical analysis, materials design and characterization,

engineering design, and technology commercialization.

“We’ve already identified several classes of caloric

materials that look promising, based on a review of the

existing scientific literature, and we are creating samples of

them for evaluation,” said Pecharsky.

Experimental work is going forward while the consortium

also assembles an informatics system that will be used as

both a database and a computational aid tool to assist in

evaluating existing and new materials.

“Within five years, we want CaloriCool to be the authority,

the resource for information on caloric materials, part of the

national materials genome,” Pecharsky said. “That’s going to

help accelerate commercialization of the technology.”

Engineering design members of the group have already

traveled to Denmark Technical University to establish

collaborations and study existing prototype systems for a

test station device being designed and built in 2017 called

CaloriSMART—Small-scale, Modular Advanced Research

Test-station. The test station will allow researchers to rapidly

assess whether new materials have the correct properties, can

perform as needed for use in a manufactured device, and use

the smallest sample necessary to produce reliable data.

“You could read up on how to go about it, but we decided

it was better to send our people and let them get their hands

on some of these systems, see how they work, and how we

can collaborate with experts to build exactly what we need,”

said Pecharsky.

All of the research in caloric cooling will go hand-in-hand

Cooler in10

Post-doctoral researcher Yibole Hargen prepares a caloric

material sample for evaluation in the laboratory. CaloriCool is

searching for a metallic compound that could potentially radi-

cally change refrigeration technology as it currently exists.

with an analysis of the economic impacts of the technology,

including scale-up, technology transfer, and raw materials

availability. CaloriCool’s goal is to discover these caloric

materials, but they must also be economical, widely available,

non-toxic, manufacturable, and create enough energy savings

and other benefits that it is attractive to manufacturers and

consumers. Early predictions are that caloric cooling systems

could result in as much as a 30 percent higher efficiency than

currently available vapor-compression products.

“What we are doing is exactly the point of U.S. Department

of Energy’s Energy Materials Network, to really shorten the

time frame for materials development to a real, manufactured

technology,” said Pecharsky. CaloriCool was one of seven

consortia established in 2106 under DOE’s Energy Materials

Network and overseen by the Office of Energy Efficiency

and Renewable Energy, specifically to address the need for

advanced materials for clean energy technologies. CaloriCool

is bringing together national labs, industry, and academia,

including Pacific Northwest and Oak Ridge National

Laboratories, the University of Maryland, Pennsylvania State

University, and Citrine Informatics, all of which have become

official partners in 2016. At present, the CaloriCool team is

working with several other potential industry partners, which

will be announced when negotiations are completed.

“The research has been out there a long time; we just

needed a new and more aggressive approach to move it from

the laboratory to commercialization,” said Pecharsky. “We are

quite confident we’ll be able to deliver, and that commercial

devices will begin to appear in stores and dealerships near

you in five to 10 years.”

A sample of a caloric compound. Caloric materials demonstrate

cooling effects when cyclically acted upon by magnetic, elec-

tric, or mechanical forces. Solid state caloric cooling systems

could potentially be far more energy-efficient and environmen-

tally friendly than traditional vapor-compression systems.

Formation of samples in an arc melt furnace, as shown

through its viewport.