Steam Trap Sensor Provides Active RFID Without Battery

By Claire Swedberg

PsiKick’s new self-powering sensors harvest energy from steam, vibration or ambient lighting to capture sensor data, then transmit that information to a cloud-based server for real-time and historical analytics regarding the operation of equipment.

Sep 14, 2018 — Battery-free wireless sensor technology startup PsiKick has released a product leveraging the energy of steam passing through steam traps—which capture condensation before releasing steam into the atmosphere—to power sensors that monitor the health of those same traps, then transmit that data to gateways and, ultimately, to cloud-based software via RFID technology. The resulting data helps manufacturing facilities and other companies identify how well steam traps are operating.

Several hundred PsiKick sensors are now being piloted by approximately five companies, ranging from the University of Michigan—where David Wentzloff, PsiKick’s co-founder and co-CTO, is an electrical engineering professor—to a consumer goods manufacturer and chemical refinery. These companies have asked to remain unnamed.

David Wentzloff

PsiKick was launched to develop and sell a portfolio of wireless sensors that harvest energy without the need for batteries. While the steam trap sensor is the company’s first product, says Brian Alessi, PsiKick’s product-marketing and business-development director, it eventually expects to release others, such as sensors for vibrating motors or other machinery. Steam traps provided the new company with a promising first application, Wentzloff says, due to the maintenance management challenge they pose for companies that generate steam (manufacturers, for example), as well as regarding the availability of that steam for creating power.

Steam traps serve as valves that discharge condensates and non-condensable gases from steam. The traps generally open when condensate needs to be removed, then close when all the condensate is gone, after which the process repeats. If a steam trap malfunctions, it will typically either stay closed, which means steam could build up and create potential catastrophic hazards, or remain open, releasing the steam with the condensates as it is generated, which can result in a waste of energy.

Brian Alessi

Alessi likens this to leaving the door open to an air-conditioned home on a hot day—the air conditioner will continue to cool the home, but there will be an unnecessary expenditure of energy. It also means that condensates will be released with the steam. In fact, he says, steam traps often fail—as much as every three to five years. Traps tend to be installed throughout sections within a facility through which steam passes, which means they can be difficult to access, or may be missed by individuals tasked with maintaining them.

Companies typically dispatch a team of workers throughout the facility to check functionality about once a year. This requires that they locate every steam trap, use an ultrasonic device and headphones to listen to the steam pressure within the trap, and then decide if it is operating properly, based on that information. That process usually takes two to five minutes once the steam trap has been located, Wentzloff notes, adding that labor costs increase exponentially since an average of 200 to 5,000 steam traps must be inspected at a typical company.

There are sensors that can capture data about a steam trap’s functionality in real time, and then transmit that information wirelessly. However, such devices require batteries, which must periodically be replaced—another labor-intensive process, according to Alessi. The PsiKick sensor is designed to operate without batteries. It comes with a temperature differential sensor, as well as an RF transponder, a processor, a memory and power management unit, and a capacitor to store steam energy in the event that hot steam is unavailable, and to generate the power required to operate the sensor. The sensors are built to last for about 20 years without requiring maintenance.

A company’s own steam trap maintenance personnel would install the sensors themselves, or with the help of PsiKick or a third party. The firm refers to the installations as “tool-less,” as the devices can simply be snapped onto steam traps. The sensors then begin collecting steam power at the trap, taking temperature measurements and forwarding the collected data, along with a unique ID number, to a gateway at 2.4 GHz, employing a proprietary air-interface protocol. The gateway transmits that data to the cloud-based server.

Additionally, a proprietary wake-up sensor in the node enables two-way communications. That node, Alessi explains, is always on and always listening, using 200 nanowatts of power. That networking scheme is known as Psifi. The gateway can then use this system to send a signal at 915 MHz, while the sensor responds at 2.4 GHz. Other frequencies could also be used, Alessi notes, depending on the application.

PsiKick’s software interprets the sensor data, then displays relevant content for facility managers on a dashboard. This includes displaying all steam traps, their locations and the temperature readings, as well as any fluctuations in those readings over time. If a temperature change signals a possible problem with a steam trap, the software can be programmed to alert authorized parties via a text message or e-mail.

The system is designed not only to reduce energy costs, but also to lower a company’s carbon footprint. If all steam traps are functioning properly, Alessi explains, the operation will not need to produce extra steam and, therefore, will reduce carbon emissions. The system also provides an analytical benefit, he notes: “With the data, facility managers will be uncovering correlations that will help them understand how their systems are operating.”

By installing the temperature sensors around a facility’s steam traps, Wentzloff says, “You now have hundreds of thousands of new data streams about temperature reading across the entire steam system.” Therefore, data can display the health of not only a specific valve or steam trap, but also the entire system. The solution will be sold as a software-as-a-service (SaaS), and users will not need to pay for the hardware.

In the long term, PsiKick plans to offer a variety of wireless systems that can serve as what Alessi refers to as “active RFID on steroids.” It includes the RT transmission and wireless sensors, but with processing capabilities, without the need for a battery. The next product may be a sensor that monitors motors and other vibrating machines, the company reports.

New products released in 2019 will also include systems for monitoring leak detection, as well as fan and bearing operations. The units could draw energy from vibration, or solar energy from ambient lighting. The company can also build hybrid systems that can draw power from multiple sources, such as one using solar energy when lights are on, then vibration at night.