Bee Inspired Swarm Algorithm Could Cut Energy Bills
When power hungry equipment like air-conditioning units and heating systems are all switched on at once, as often happens in commercial buildings. Power consumption spikes, and a building’s owners are left with hefty peak-demand charges on their electricity bills.
A Toronto based startup, REGEN Energy, says that it has come up with a way to reduce energy use by mimicking the self-organizing behavior of bees. The company has developed a wireless controller that connects to the control box on a piece of building equipment and functions as a smart power switch.
After several controllers have been activated, they detect each other using a networking standard called ZigBee and begin negotiating the best times to turn equipment on and off. The devices learn the power cycles of each appliance and reconfigure them to maximize collective efficiency.
The aim is to have everything come on at different time, but without sacrificing individual performance. The devices work through this problem using a “swarm algorithm” that coordinates activity without any single device issuing orders.
This marks a big change from the centralized top-down systems currently in use in most automated building systems. There are some researchers who say that the decentralized approach to energy management offers a simpler and therefore cheaper, and more effective way to manage supply and demand in a finely balanced electricity system. Some even believe that it could be an early prototype for emerging smart grid technology.
Mark Kerbel, co-founder and chief executive officer of REGEN Energy, said. “Every node thinks for itself,”. Before making a decision, he explains, a node will consider the circumstances of other nodes in its network. For example, if an air-conditioner needs to cycle on to maintain a minimum temperature, a node connected to a fan or pump will stay off for an extra 15 minutes to keep power use below a certain threshold. “The devices must satisfy the local restraint but simultaneously satisfy the system objective,” says Kerbel, adding that a typical building might have between 10 and 40 controllers working together in a single “hive.” The devices are simple and quick to install and, because there’s no human intervention, and they require no special training to use.
David Chassin, a scientist at Pacific Northwest National Laboratory’s energy-technology group, said “You’re seeing a lot more interest in this on a modest scale,”. The lab is heading up the GridWise smart-grid initiative.
The savings and other benefits could extend beyond electricity savings for individual building owners. Today’s electricity system is designed for peak consumption, which means that power plants are built to satisfy those few minutes of each day when power demand surges well above daily averages. By reducing peak demand on a large scale, utilities can maximize the operation of existing power plants while reducing the need to build new plants for occasional use. Another potential benefit is reduced carbon emissions, since power plants that supply peak electricity tend to be less efficient and fueled by coal and natural gas.
Kerbel first came up with the idea of using a swarm algorithm to manage power consumption in 2005. “We were politely told that this style of control just isn’t ready and requires far more academic research,” he says. “It’s difficult to think outside the command-and-control box and allow this leap of faith–that is, relinquishing decision-making capabilities to individual nodes of the collective.”
It is true that engineers typically want constant feedback so that they can measure system operation and make refinements. REGEN’s technology dispenses with that, but its application will likely make some mistakes, but in less than mission critical environments, simplicity and cost savings far outweigh any shortcomings.
Tests have so far demonstrated that buildings such as hospitals, hotels, shopping malls, factories, and other large facilities, could save as much as 30 percent on their peak-demand charges. Those savings, REGEN claims, more than cover the cost of renting the devices, which is an option for major electricity consumers reluctant to buy the technology up front. If the devices are purchased, the payback is less than three years, says Kerbel.
There is sure to be much more interest in this type of application over the coming years, as the U.S. economic stimulus package calls for more investment in energy efficiency and smart-grid technologies. This is the classic ‘low-hanging fruit’ that advocates as high up as Steven Chu are currently promoting so strongly.