Energy Harvesting Wireless Sensors Balance Hotel Comfort and Energy Savings

Guest comfort is a top priority among hotel owners and is vital to an establishment’s desirability. Savvy hotel guests expect comfort and convenience, regardless of a hotel’s star rating, and an increasing number are becoming more mindful of their environmental footprint while traveling. Unfortunately, considerable energy is wasted in hotels, due in part to the lack of automation and control in guest room operations. More often than not, upon checking in to a hotel room, including those with luxury accommodations, guests find that they have limited or no control over the temperature settings.

Another common scenario finds guests opening a window to cool down an overheated room, because the thermostat is not working properly or is controlled by a central system. This inefficiency and lack of control in guest room operations wastes energy and eats into hotel profitability. As a result, energy management technology, specifically battery-less, wireless sensors are being adopted and deployed at an accelerating rate. Hotels around the world are now discovering that wireless sensors enhance “climate” control, improve guest comfort and lower utility costs. The bottom line to hotel operations is that this important combination of guest-centric benefits improves energy efficiency in the facility.

Wireless Technology

With wireless technology that harvests energy from the surrounding environment to power sensors, hotel facility managers have a cost-effective solution that enables guests to control room temperature and lighting. When a guest room is vacated, sensors restore the temperature to optimized pre-sets put in place by the facility operator. Signals can be sent to turn off all light switches, and even TVs, when the room is vacated. This eliminates unnecessary energy use when a room is vacant and rids hotels of a major contributor to energy waste. When the guest re-enters the room, an occupancy sensor, or a wireless key card switch automatically restores the guest’s preferred lighting and temperature settings[...]

To appreciate the impact that wireless sensor technology has on hotel energy consumption, consider the following: average hotel occupancy rates are currently running at around 70 percent. “Sold” rooms are occupied, on average, for only nine hours within a 24-hour period, meaning that a hotel room is unoccupied over two-thirds of the time. Despite this, many unoccupied rooms have the heating or air-conditioning running at high levels, even with a window or balcony door open. Very often lights, TVs or other appliances are also left on. Consequently, having the ability to automatically determine real-time room occupancy, including window and balcony door sensing, makes it possible to save between 20 and 30 percent on in-room energy consumption each year.

Room occupancy can be determined by a number of factors, most commonly using a key cardholder inside the room where the guest inserts the card into the holder to energize the room upon entering and vice versa upon their exit. Alternatively, a door-opening sensor combined with an occupancy sensor inside the room can determine room occupancy without any guest interaction, if preferred[...]

These sensors and switches remain maintenance free for decades by using tiny amounts of energy available in their surroundings, including mechanical, solar or thermal. The sensors can store energy for multiple days for uninterrupted operation when no energy source is available. The sensors can be installed in a matter of minutes as a simple stand alone system per room, or they can be integrated into a building management system, a hotel PMS or even the Internet.

(Source Bottomline, June 2011)