Smart Exergy: Power-Saving Wireless Communication

On September 2, I visited SmartExergy, a 4-year old startup that provides wireless monitoring solutions for Smart Grids, Smart Homes, and Smart Production. The company is co-located with a number of other startups, in a building adjacent to the University of Freiburg’s Faculty of Engineering. Omar Gorgies, Smart Exergy’s CTO and a Ph.D. student in safe systems at the University of Freiburg, showed me around.

Patented Wake-Up Technology and Product Overview

SmartExergy’s products are based on their patented power-saving “wake up” communication strategy. Basically, networked devices using the company’s protocol default to a low-power sleep mode (the “quiescent state”), in which the device is essentially off except for one wakeup channel. When the device needs to be woken up (put into its “operating state”), a radio signal is sent to the wakeup channel. The device then communicates as it usually would before turning back off. This communication approach, as the company states on its website, can “reduce power consumption of wireless sensors to less than 3µA without compromising on the availability.” SmartExergy fundamentally believes that all electronics should be wireless and networked, and that their protocol can ensure these networked devices don’t use too much energy.

 

Solar Panel Solutions

SmartExergy’s first product based on this protocol was for solar panel monitoring and optimization. The product consists of boxes that attach to the backs of solar panels (one box per panel) and sense various parameters such as the produced voltage, current flow, and temperature. The boxes then communicate wirelessly with a portal/gateway and act on the sensed information to maximize solar panel performance. For instance, the boxes can sense when a shadow has fallen across one of the solar panels (which decreases the performance of the entire solar array*) and omit that panel from the solar array circuit to increase performance. The boxes can monitor panel health and aging, and detect potentially fire-causing electric arcs in the panels or cable connectors.

SmartExergy is also working on theft prevention functionality. According to Mr. Gorgies, there are “solar mafias” that steal panels from solar farms, and these mafias are hard to catch because they steal panels so quickly (within an hour or two). SmartExergy’s upcoming theft detection system senses disruptions in the wireless signals sent out by the monitoring boxes, algorithmically identifies the cause of the interruption (theft? a bird? the wind?), and sends an alert if necessary.

Additionally, SmartExergy has focused on PV system “rapid shutdown” functionality for the American market. This functionality allows PV systems to be safely disconnected in case of fire, and will be mandatory for all US rooftop solar PV systems (and some ground-mounted systems) by 2017.

The price for SmartExergy’s solar panel monitoring solution varies based on the functionality desired. For instance, customers with solar panels in a large field may not need the shadow-optimization functionality, since there are no objects nearby to cast shadows. While the product hardware is universal, SmartExergy can change the software based on what the consumer is willing to pay.

OVERVIWE-ICON.png

Overview of SmartExergy’s solar photovoltaic solutions. (Image from https://www.smartexergy.com)

Although the PV module was SmartExergy’s flagship product, they ran into some trouble with the business case. In particular, the PV market has gone through a rough time for the past 2 years. SmartExergy found that people weren’t buying solar panels (and therefore SmartExergy’s product) due to these changing market conditions, so the company branched out into additional products to sustain its existence in the meantime.

 

Smart Home Solutions

One of these products is a temperature monitoring and control system for the home. The solution comprises three parts: a gateway, a wall-mounted tablet charger, and a smart set point controller. The gateway sits on the wall and collects air temperature data that can be sent to a portal via end-to-end secured communication. Customers can view this data and control temperature set points through an online portal or tablet app (and can place their tablet in the wall-mounted charger if they want an in-home temperature display). The smart set point controller, developed by another company in the building and powered through energy harvesting,** then adjusts the temperature based on the customer’s settings.

 

Other Solutions

Mr. Gorgies told me that SmartExergy’s protocol can also be used for a myriad of additional solutions requiring wireless communication. For instance, SmartExergy is currently monitoring a large hospital backup battery (12 V, 25 A pro cell) that allows the hospital to continue operating in case of a blackout. Such monitoring can help increase battery life and health. The company is also working to make finger-prick diabetes monitoring solutions wireless, and to increase quadcopter communication distances to more than 30-40 meters. And, as the company says on its website, “SmartExergy is opening the door to new applications to make Power Systems more intelligent, profitable and safe.”

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* Solar panels in a solar array are generally divided into small groups called strings, and the panels in these strings connected in series. In other words, the same current flows through all panels in the same string. If one of the panels gets shaded, then the current across that panel (i.e. the power that panel produces) decreases, which means the current across the entire string decreases. Removing the shaded panel from the circuit prevents this decrease in current. [back]

** The smart set point controller connects to the conductive element on a home heater. When the heater is on, some current from the conductive element flows through the smart set point controller device and charges its internal capacitor (i.e. energy storage component). [back]

(Note: The company reviewed the above writeup before its publication.)

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