MENLO PARK — How about shoe inserts that employ simple tools — water, air and small, low-voltage batteries — to help bring down U.S. energy costs and keep wearers comfortable, no matter what their immediate surroundings feel like?
Menlo Park-based nonprofit research institute SRI International, along with Stanford and UCLA researchers, is developing footwear dubbed ReBOOT that will keep people comfortable in unsuitable environments. It comes in response to a challenge from the U.S. Department of Energy: Can you cut a building’s energy costs by developing a system to heat or cool workers directly?
According to SRI, 13 percent of energy consumed in the United States — and 40 percent of energy used on average in homes — comes from heating, ventilation and air conditioning.
“The basic idea was if you could cool or heat people directly and let the temperature in the building vary hot air and cold, then you could save a lot of energy,” said Roy Kornbluh, SRI Robotics principal research engineer. “You’re wasting energy heating or cooling the ceiling or the floor or the walls (when) all that matters is how hot or cold you are.”
ReBOOT is a rather low-tech system by SRI standards. It employs a low-voltage battery that powers a pump that moves water through a shoe insert made of “thermally conductive materials to manage heat transfer from the soles of the feet” and fans that keep the water at room temperature, even as the body tries to heat the water to body temperature. A working prototype in SRI’s lab uses a laptop cooling fan.
The technology is based on research into mammals at Stanford, which led to the creation of “dog booties” worn by military dogs in Afghanistan on their paws, a more rudimentary system that employed frozen packs of ice. Dogs’ paws are made up of glabrous (non-hairy) skin, which is where much of their internal heat is transferred. The same is true in humans, across four regions: palms, foot soles, ears and upper cheeks. Kornbluh said wearables that heat or cool these regions “can heat or cool the body 10 times faster” than standard devices such as cooling vests or thermal blankets.
“Think of a car’s cooling system,” he said. “Your body core is the engine, the radiator is the glabrous tissue and your blood vessels are the hoses to the radiator, so putting on a cooling vest is like putting ice on the engine block. Compared to using the radiator with air flowing through (it), you’re just not doing the job.”
The general idea is that before it’s marketed, ReBOOT will allow a wearer to feel 4 degrees cooler or warmer than the external temperature. After either spinning the venture off into a separate company or partnering with a footwear manufacturer, SRI plans to continue increasing the disparity between outside and internal temperature.
“We’re still doing the fancy new materials research, and we think we have ideas on fans that are better than existing fans,” Kornbluh said.
With less than a year under its belt, ReBOOT is still at the prototype stage with ongoing human trials at Stanford, but the technology could lead to wearables for more extreme conditions, such as gloves and socks worn underneath protective gear for doctors responding to an Ebola outbreak in hot climates or ones worn by athletes during breaks, allowing them to recuperate faster.
“As Stanford professors have shown, if you can keep the body core temperature low, you can continue exercising at a much higher rate,” Kornbluh said.
Down the road, ReBOOT could be used by people suffering from medical conditions such as multiple sclerosis and thyroid problems.
“There are various conditions where people lose their ability to thermal-regulate,” he said.
It could also help emergency responders deal with hypothermia and heat stroke cases.
“The Stanford team has already shown the ability to rapidly cool or heat people in operating room environments,” Kornbluh said. “A first-aid person could easily carry something like this.”
Email Kevin Kelly at kkelly@bayareanewsgroup.com or call him at 650-391-1049.
