Electric Power

Battery-Free Sensor Startup Takes Aim at Industrial Efficiency

Part of the team that brought us the world’s smallest computer in 2015 brings the future of computing technology into the present.

Large facilities throw away money and energy on inefficiencies like steam loss and degrading motors, but the new U-M startup Everactive aims to change that. Their key innovation is this: their sensors that run without batteries, enabling them to pinpoint problems as soon as they occur without the need for routine maintenance.

Routine maintenance may be on hold during COVID-19 shutdowns, but a set of battery-free wireless sensors can alert the facilities team at U-M to emergency repairs needed on 40 steam traps. The traps are designed to open periodically, clearing condensation from steam pipes. But they can get stuck open—continuing to clear the condensation but also pouring out steam.  Worse, the traps occasionally fail shut, potentially leading to an explosion.

Facilities managers typically run steam trap inspections once per year, or even less frequently, said David Wentzloff, co-founder and co-chief technology officer of Everactive, and also an associate professor of electrical engineering and computer science at U-M.

“It’s like a homeowner putting off the decision to fix a leaky faucet, or insulate the attic, or upgrade to a high-efficiency furnace. Sometimes they just don’t know how much money they are losing by doing nothing, and other times they know upgrading will pay off in a year or two but just don’t do it because they have other priorities,” Wentzloff explained.

At U-M, the most accessible steam traps undergo annual inspections, while harder-to-reach traps go up to three years between checks.

“If a steam trap fails on day one after it has been tested, you could be blowing steam through it for three years,” said Aerik La Fave, general foreman for mechanical systems at U-M.

Erik Boyer, a regional energy manager for the office of campus sustainability at U-M, explained that a single failed trap can create 80 million metric tons of extra carbon dioxide emissions over the course of a year, at a cost of $19,500.

The high cost of a leak makes a subscription to Everactive’s service a good value, at $300 per sensor per year. The 40 traps at Medical Sciences Research Building III are currently 8 months into the pilot. Everactive provides and maintains the sensors, analyzing the data that they generate. Operators receive notifications when a steam trap fails, with details about where that trap is located.

Everactive also makes sensors for industrial motors, which run fans, belts and more. On the way to failure, these motors can become inefficient, increasing operating costs. But like the steam traps, a large facility has so many motors that it is impractical to inspect them all.

Because Everactive sensors harvest energy rather than rely on batteries, they require no routine maintenance. The company believes that they can run for 20 years.

The secret to success in running sensors on ambient heat, vibration and indoor lighting is the very low power requirements of the electronics. They need just 10 microwatts of power (about a millionth of the power needed by an LED lightbulb) to make measurements, process them on the device, and transmit the results wirelessly. Low-power radios are Wentzloff’s contribution to the ongoing work at U-M producing some of the world’s smallest computers.

Everactive was formerly known as PsiKick, which built chips that could enable sensors to run without the need for batteries. But with a push from their investors, the team hired in more expertise so that they could build whole sensors, rather than just provide chips to device makers.

“Everyone has a rap sheet of things they want to know, but they don’t want to replace all these batteries,” said Wentzloff. “Our devices make it practical to find and fix the inefficiencies that businesses today treat as losses.”