NATIONAL REPORT—Believe it or not, guestroom energy management systems have been around for almost 30 years now. According to Lodging Technology, it originated infrared occupancy sensor-based hotel energy conservation in 1980. It is only in the past few years, however, that wireless versions of the many hard-wired systems on the market have become available. Some vendors are just rolling out their wireless offerings. No two wireless systems are exactly the same but they all rely on thermostats, motion and/or passive infrared (PIR) occupancy sensors, along with door switches and transceivers/controllers to power down heating and cooling when guests have left the room or left a balcony or patio door open. While some wireless systems are very basic, others integrate with property management systems and/or provide centralized monitoring and reporting capabilities.
Hard-wired systems are still very reliable but can be cost-prohibitive to install in existing buildings, especially at the midscale and economy end of the lodging sector. Wireless systems are not bound by construction or fixture limitations. They are flexible and operate using IEEE 802.14.4 ZigBee wireless protocol—now a widely accepted networking technology. While some wireless systems may currently cost more than their hard-wired counterparts, Jeff Sobieski, chief operating officer for Telkonet, Inc., says some are currently less expensive and the technology is only going to become more affordable.
“A year from now, all of our sales will be Networked Telkonet SmartEnergy systems (NTSE),” Sobieski says.
NTSE is indicative of how many wireless systems work. It utilizes a ZigBee wireless IEE802.15.4 “mesh” network, where each device functions as a wireless repeater and enables energy management thermostats to communicate with each other and aggregate communications up to a single master NTSE Gateway Server on site. Through the company’s Telkonet Central, one can manage and monitor all NTSE devices via a Web-based portal. Sobieski says an online “dashboard” allows a hotel owner to see how many rooms are currently occupied, view estimated kilowatt-hour savings, and adjust temperature setbacks. Alerts, or “alarms” can be set to go off when maintenance is needed.
Recovery Time Technology
Telkonet’s Recovery Time technology measures temperatures in a room every three seconds. Each room is evaluated independently in real time to determine its energy efficient temperature, or setback, based on many environmental conditions, such as room location, window placement, dry versus humid climate, varying weather conditions, the HVAC unit, and so on.
As mentioned earlier, in most guestroom scenarios where energy management systems are in place, there are four main components: the thermostat, sensor, the switch (or switches) and the transceiver/controller. In Onity’s SensorStat Wireless DDC system, the infrared sensor is built into the thermostat. Onity’s Wireless innPULSE system, which works in conjunction with the SensorStat Wireless DDC, allows a manager to control HVAC systems from the front desk one floor at a time or individually by guestroom. Room temperature, humidity, occupancy, run time and other metrics can be monitored. Brian Bevins, business development manager for Onity’s Energy Management Systems division, says Onity’s system can reduce equipment run time by 25 to 35 percent.
Lodging Technology recently introduced its GEM Link Wireless energy management system. What is unique about it is its ability to program a thermostat to four setback levels. For example, in a room heating situation where the guest has been gone from a room for five minutes, the system can be programmed to set back the temperature by two degrees. After the guest has been gone for an hour, the thermostat can be programmed to set the temperature back yet another two degrees.
“The timing and temperature setback for heating and cooling are flexible and programmable,” says Bill Fizer, founder and president of Lodging Technology.
The GEM Link Wireless system includes a Programmer Maintenance Module that allows one to monitor room occupancy and other status features and change programming parameters from outside the guestroom.
Humidity Control, Air Refreshing
As part of its Integrated Room Automation System, INNCOM Internationall offers the e4 Smart Digital Thermostat—E528. It can be equipped with an on-board ZigBee transceiver, infrared transceiver, a passive infrared occupancy sensor, outside temperature display, and the ecoMODE green button that allows guests to opt in to a host of environmentally friendly programs predetermined by the hotel. The e4 Smart Digital Thermostat can be expanded to actuate humidity control algorithms that control the rate of air refreshing cycles in the guestroom and suppress the growth of mold, mildew, and other humidity-caused biological growth.
Like its competitors, the Energy Eye System uses a combination of passive infrared sensors and wireless technology to independently control room HVAC temperatures while occupants are away. With its system, Energy Eye says an HVAC duty cycle reduction of 50 percent is possible, with total project savings in the range of 10 percent to 40 percent being common. As one option, Energy Eye offers its sensor in a smoke alarm casing. Sometimes guests think the traditional room-corner sensors are cameras.
A typical guestroom is unoccupied 65 percent of the time. Investing in a system that powers down heating and cooling equipment when rooms are vacant, especially in areas where significant utility rebates are available, makes a lot of financial sense. (Go to www.dsireusa.org for incentives information.) In addition to reducing energy costs, guestroom energy management systems also reduce run time for HVAC equipment. This extends equipment life and reduces maintenance-related time and costs. Filters, for example, need to be changed less often. Energy management systems also demonstrate a commitment to the environment and reducing one’s carbon impact. Numerous surveys have shown that both business and leisure travelers alike seek out green hotels when making travel plans.
Be sure to also check out Energex, Entergize, EnOcean, and Energy Authority International.
Glenn Hasek can be reached at editor@greenlodgingnews.com.
