Wireless Goes Batteryless
Part 2: Installation of Wireless Systems, Integration With Existing Controls Can Be Cost Effective
Installation of Wireless Systems, Integration With Existing Controls Can Be Cost Effective
April 2010 - Power & Communication
Today, cost is on every facility manager's mind. But costs depend on the installation — along with the myriad variables of building design, age, tenant preferences and more. Because wireless, batteryless devices do not require new cabling, the peel-and-stick devices usually require little more than integration with existing controls.
"When talking about new construction, the savings for going wireless is 15 percent less for first cost, but it's about 50 to 80 percent less for retrofits," says O'Callaghan.
In variable-occupancy environments, such as hotels and dorms, it's possible to achieve a return on investment in less than two years, says Graham Martin, chairman of the EnOcean Alliance. "It can be as low as eight months," he says. "But for offices and commercial buildings, the ROI is more like two to four years."
According to Martin, installation of the basic occupancy sensor configuration listed above takes less than an hour for an average hotel room.
Choosing occupancy sensors makes sense, says O'Callaghan.
"Studies have shown that most commercial buildings are occupied only 60 percent of the time. The real key is to deliver services such as lighting or HVAC when and where needed."
And for Martin, another big driver of popularity is the lack of business interruption. "Owners can save typically around 20 percent for heating and lighting without any business interruption," he says. "We have installed devices in hotel rooms in the time between when one guest checks out of the room and another checks in."
The major benefits of retrofitting EnOcean devices include:
- Speedy, flexible installation and startup
- No wiring and no breaking into walls or ceilings
- Energy savings
- Freely positioned and retrofitted products
- No maintenance (replacing batteries, etc.) after installation
- Interoperability and scalability
- Compatibility with building automation systems, including ones that run EIB/KNX, LON, BACnet and TCP/IP
- Re-deployment of devices in other parts of the building according to tenant needs
- Device longevity (50,000 cycles for switches and approximately 25 years of service life for thermo and solar harvesters).
Flexibility is Key
As an example of the technology's use, in the Olympic Village in Whistler, British Columbia, more walls were temporarily added to create additional housing for the incoming athletes.
"They used EnOcean products so that they didn't have to run any wiring through the walls," Martin says.
But EnOcean devices are used in more traditional commercial applications, as well. "Many building owners say, 'I'd like to reduce energy consumption, but installing it can be invasive to the building,'" says O'Callaghan.
He cites a Leggat-McCall retrofit of office space in Boston in 2009. "They like to use what they call 'smart floors and dumb walls,'" he says. "Cabling is run through the floor; the walls and ceilings use EnOcean devices to eliminate having to fish lines through walls."
The design allows the company to re-configure office space with maximum flexibility. The 10,000-square-foot retrofit of the LEED Platinum-certified building was completed in 15 days.
And when tenants' needs change, the flexibility to re-position the devices is vital. Imagine that an existing building was being converted for use to an assisted living center. "It would be easy to lower the switch heights for wheelchair-bound tenants," Graham says.
Flexibility and the desire to have devices that require neither power nor maintenance will be big drivers for the North American market, say Martin and O'Callaghan.
"It all gets down to economics," O'Callaghan says. "It's going to be a buyer's market in the years ahead."
What's on the Horizon?
EnOcean isn't resting on its laurels, and is working on how it can include other types of technology in its devices. According to Graham Martin, chairman of the EnOcean Alliance, rotational and vibration energy-harvesting devices are in testing at the moment. Rotational devices could be mounted on any metering equipment that rotates because of flow. Gas and water meters are the natural applications, says Martin, eliminating the need to replace batteries in many current meter-monitoring devices.
Vibration monitors can be used on anything that moves or causes vibrations — machinery, vehicles, even humans.