EnviroGrid Introduced

EnviroGrid is a system that automatically controls energy consumption in a building, without the benefit of primary system controller hardware. Instead, individual controller hardware units work together wirelessly.

The system manages the building’s energy conservation with a focus on reducing consumption during peak usage times across the electrical grid, when electrical power is the most expensive. The EnviroGrid system attempts to minimize the impact of its energy conservation techniques on the building and its occupants while achieving maximum savings.

The organization of the EnviroGrid system is interesting, as it doesn’t have a central management source. Instead, the system includes multiple wireless controllers connected to devices throughout the building. The controllers communicate with each other using ZigBee, a wireless networking standard. The controllers manage energy consumption on the fly by negotiating the best times to power up and power down different pieces of equipment.

Most building-automation systems work from the top down, with a primary system controller. EnviroGrid, however, uses a “swarm” configuration, such as is found in nature. For example, in a colony of bees, no single entity tells the individual bees what to do, but they still know their own jobs and know how to work together to maximize efficiency.

“We don’t need to control a system with top-down commands,” Kerbel says. “That doesn’t work in nature.”

For example, a top-down system might not be flexible enough to know that by keeping a refrigeration system powered down for an extra 20 minutes, the building can avoid triggering higher peak charges from the power company today, while minimally affecting the internal temperature of the refrigeration system.

EnviroGrid‘s Development

Kerbel and Roman Kulyk, Regen Energy’s CTO, co-founded the company in 2005, sparked by the large power blackout that hit the northeastern United States and parts of Canada in August 2003.

“We caught the bug during the blackout,” Kerbel says. “We had a goal of doing something with the environment. We decided we were going to come up with something, we didn’t know what, but something.”

Kulyk had experience working with building control systems. He knew they were complex and highly customized, and they didn’t have a great track record of working correctly.

“Roman is the engineering brains behind the electronics,” Kerbel says. “He etched the first boards in his bathroom sink at home. The sinks still have some of the acid stains.“

Keep It Simple

Installation of the system is easy, which enhances the desirability. Building managers don’t need a lot of time to either manage or install the system, which they appreciate.

“With our system . . . it’s a 20-minute installation on a single HVAC unit,” Kerbel says. “If the building has 10 units, and you take one unit offline for 20 minutes, nobody ever notices anything is happening.”

Kerbel says in every building Regen has installed the system, the company has found something operating incorrectly that building engineers thought was being monitored properly, no matter what type of building control system they were running. For example, a fan left running on a rooftop air-conditioning unit overnight could cost a building owner $1,000 per year, Kerbel says.

Even if building owners are more apt to look at the green of saving money vs. the green of environmental concerns when selecting a system such as EnviroGrid, environmental concerns are always present these days in certain areas of North America, Kerbel says. In California, for example, power outages are a constant concern, and utilities ask companies to try to better manage their electrical consumption during peak demand to help the overall electrical grid and reduce outages.

“In the back of the minds of building owners, they know there’re no customers with outages, and there’s no work from employees with outages,” Kerbel says. “There’s not just a nice ‘green’ message to EnviroGrid, but also a real-life message to reduce grid stress.”

by Kyle Schurman

EnviroGrid In Action The EnviroGrid system relies on the ZigBee wireless networking standard to allow the controllers (Figure 1) to communicate with each other. The controllers, which measure 4.27 x 6.25 x 1.17 inches, make use of transceivers and microcontrollers from Microchip (Figure 2), an Arizona technology company. "We were one of the earliest to make use of Microchip's ZigBee transceiver," says Regen Energy CEO Mark Kerbel. "Their engineering team worked with our engineering team. We're using ZigBee for what it was meant for. Some people are using ZigBee for 3- to 5-mile spreads. It's not designed for that. It is meant to be localized in a building or in a campus of buildings." Each controller is connected to a device that has a large electrical power draw. The controller measures its usage and then communicates that data with other devices on the network to manage overall power consumption (Figure 3) in the building. Kerbel says EnviroGrid controllers are achieving about 850 yards of transmission distance, when they have clear line of sight. Even in a building with concrete and rebar construction, Kerbel says the units regularly are transmitting through six to eight floors (Figure 4). The controllers include a cellular modem, too, allowing for remote connectivity, through which they can transmit the collected data to a centralized location (Figure 5). From there, the system’s software can upload the data (Figure 6) to the Web, where the building owner can remotely access the data, looking for devices that are causing problems. "The Web portal sees everything that's going on, minute-by-minute wattage usage," Kerbel says. "By using the cell model, we're listening to the chatter, back and forth. We can very quickly identify things like what loads are left on overnight that don't need to be." Source: REGEN Energy

Avoiding Peaks Some utilities base commercial electrical rates on the peak demand for a customer that occurred during the month. For example, a company might use a peak of 400kW at 3 p.m. on a particularly hot day because nine of 10 HVAC units operated simultaneously. With EnviroGrid, maybe only six of the HVACs kick on at the same time, shrinking the peak number, and perhaps they run longer to make up for the difference. The EnviroGrid controllers can manage the system independently, working together to avoid large peak usage. "Nobody in the building even notices what happened," Kerbel says. "It just ticks along in the background. By the end of the afternoon, you might notice it a little bit, but most people just chalk it up to being a particularly hot day. By 6 p.m., everything goes back to normal. Everybody wins." As shown in portion A of the graphic below, electrical devices like pumps, HVACs, and controllers, when left with no organization, will operate at whatever times they need to, potentially leading to a huge peak number at certain times. At other times, the electrical power demand might be zero. As shown in portion B, EnviroGrid first can manage the demand to reduce peak by spreading out when certain devices power on, shifting power usage away from high-demand times to take advantage of low-demand times. Finally, as shown in portion C, EnviroGrid then can dial down the power consumption of certain devices, further reducing the peak demand for the building. Without management from a system such as EnviroGrid, the building might just shut down all of its HVAC units during peak load times, and the temperature in a building might go from 72 to 77 degrees, Kerbel says. However, what happens instead if the duty cycle is dropped only by 10% or 20% by shutting down only a few HVAC units? "Instead of each AC unit running two hours, maybe it runs 1:40 or 1:20 instead," Kerbel says. "When they see there's a 10% reduction, and the people don't feel it, it works.“ EnviroGrid relies on the ability of the controllers to communicate with each other in real time, wirelessly, and then make decisions based on the current data. Source: REGEN Energy