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Posted in | Nanomaterials

Solar Thermal Icemaker Provides Cooling for NanoQ Containers to Store Vaccines

Published on March 26, 2014 at 2:38 AM


Sandia National Laboratories chemist Eric Coker, left, looks over shipping containers developed by Santa Fe businessman Bruce McCormick that safely transport and store temperature-sensitive vaccines and biopharmaceuticals. Coker helped McCormick create a solar thermal icemaker to provide cooling for the containers. They worked together through the New Mexico Small Business Assistance Program. Credit: Randy Montoya

"The vast majority of the world's population lives in areas where electricity and refrigeration are not reliable," said Bruce McCormick, president of SAVSU Technologies of Santa Fe. "It is difficult to get vaccines to these areas. We're talking several billion people."

McCormick, an inventor, knew about the obstacles in vaccine distribution in developing countries. Vaccines and other biologic materials, such as blood, tissue, genes, stem cells and proteins are made of living organisms that degrade in warm temperatures until they are no longer effective. And freezing is an even bigger danger. "Seventeen to 39 percent of all vaccines are exposed to freezing temperatures through improper storage, and it kills them," he said.


Ice can cause inadvertent freezing


"Inadvertent freezing is the result of good intentions," McCormick said. "The vaccines are in a cooler going from point A to point B. Ice is the primary means of thermal storage, and the feeling is that more is better. The vaccines end up freezing."

Transportation is hard to manage, and the range of vaccine distribution is limited by how long a cooler can maintain the proper temperature. "If you have a cooler that can keep the vaccine alive for 24 hours, that's how long you have to load, bring it to the village, community or health care center and administer," McCormick said. "As a result there are complicated logistics in moving the vaccines from, for example, a national distribution facility where they have reliable electricity to a remote clinic. But they have to get there. It's referred to as the last mile."




The system uses ice because it goes to places where there are no special resources and water is common. "It's simple to operate. People don't need to be trained," McCormick said.

PATH asked if the box could store medicines longer than 10 days if the ice was swapped out. Replacing the ice would require refrigeration in areas where electricity is unreliable. "Even in big cities there are power outages," McCormick said. "You have to have power running 24/7 with no interruption when you use standard refrigeration systems."

Chemist gives entrepreneur a hand


The challenge was to make the NanoQ a long-term storage device instead of just a transportation container. Ice would have to be made in the field. "I found information about a large solar icemaker made at Sandia in the 1980s using a refrigeration technology called adsorption," McCormick said. "I wanted to find one of the original engineers on the project."


"Bruce needed a passively driven refrigeration system," said Iverson, now a professor at Brigham Young University. "I started digging into who had worked on the project, what the system's components were made of, and the process by which ice is made using solar energy."

Sandia physical chemist Eric Coker joined the project. "Brian did the engineering and I took his recommendations and applied chemical knowledge to fill in the design gaps," Coker said. "I researched what materials would make it work at the scale Bruce needed. It had to be portable and completely off grid with the only inputs being sunlight and water."


The fluid moves by gravity to the condenser where it liquefies. At night, when heat is no longer driving fluid off the carbon, the condensed liquid evaporates and the gas is absorbed back into the carbon, drawing heat from the environment. That reaction has a cooling effect that freezes water in a trough, creating from 2 to 12 pounds of ice a day. "It needs no electricity or photovoltaic cells. It's a refrigeration cycle," Iverson said.

McCormick said the icemaker is key to SAVSU's ability to offer the NanoQ to international agencies as a permanent replacement for costly, impractical refrigeration systems. "They go together," he said.

Helping Third World get vaccines 'a good feeling'


Coker, who has been at Sandia 13 years, said it was exciting to work on a project that saves lives around the world. "It's a really good feeling," he said. "It's very gratifying to think the work I did could help people in Third World countries receive vaccines that are still in good shape."

The NanoQ is used at community health centers in Asia, Africa and Latin America. "We've seen it work," said McCormick. "The purpose of the boxes is to assure that vaccines are available at the community level when outbreaks occur. The NanoQ coupled with the solar thermal icemaker is a game changer in how vaccines are stored and distributed in developing countries."


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