Wireless Energy Management

Hotel owners are under enormous financial pressure when it comes to running their properties. Fluctuation in occupancy, a highly competitive market and increasing energy costs are just some of the concerns facing the hospitality industry. More hoteliers are recognising the environmental and financial benefits of retrofitting their existing buildings to improve energy efficiency and make substantial savings.

For example, The Courtyard Marriott Kauai in Hawaii achieved an impressive 35 percent saving in energy with self-powered wireless entry door sensors, occupancy/motion sensors and temperature sensors in each guest room.

More recently at the historic Hotel Blesius Garten in Germany, an individual room control system was installed and 20 of their 60 rooms were equipped with self-powered, wireless thermostatic radiator valves.

Burden of batteries
Using wireless solutions that can be flexibly placed eliminates the need to install wiring and conduits and can be installed in about the same time it takes to clean a hotel room.

However, the system could comprise hundreds to thousands of these sensor devices all requiring power and communication capability. Battery-powered wireless devices can be costly and time consuming as batteries last for only a limited time and must be replaced regularly and disposed of properly.

Self-powered systems
To solve these challenges, there are also self-powered wireless systems on the market, which are found in all kinds of buildings today. An energy harvesting wireless module gathers the power it needs to operate from the surrounding environment, including motion, light or changes in temperature. This allows control systems based on sensors and switches to operate independent of an external power supply such as wires or batteries. The ambient energy obtained in this way is sufficient to measure data and to send a wireless signal as a command and control message.

The key to energy management
Based on self-powered energy harvesting technology, an intelligent HVAC system can be realised by wirelessly interconnecting automated thermostats, window contacts, key cards, humidity sensors, occupancy sensors and CO2 sensors. These are just a few examples of the self-powered products in place, which regulate climate control automatically.

At the heart of such a battery-less wireless in-room energy management solution could be the wireless keycard. Upon entering the room, the guest initiates control of the lighting, HVAC system, and television by simply inserting the keycard into the keycard reader. The wireless signal is powered by the movement of placing the card into the reader. When guests leave and remove the keycard, all room lighting is turned off, the television is powered down and the HVAC system is set back into “eco saving” mode.

A 13-month payback
The popular Courtyard Marriott Kauai hotel maintains a high occupancy rate and therefore, the wireless components needed to be installed in a short time frame to avoid rooms being left vacant.

Using a self-powered wireless entry door sensor, occupancy/motion sensor and temperature sensor in each guest room, the hotel staff can now automatically determine room occupancy, set cooling setbacks and initial comfort levels without adjusting the thermostats in each single vacant room. The hotel operator now benefits from the 35 percent energy savings, as proven by on-site tests that compared identical rooms with and without the equipment. The hotel is now on track for a 13-month payback even without rebate incentives.

Historic ambiance consumes too much energy
The Hotel Blesius Garten is a family-run, 4-star hotel in Trier, Germany. The hotel’s 60 rooms are housed in a historic building; however, the older structure was less energy-efficient, especially when it came to heating. In December 2014, the hotel installed an individual room control system and equipped 20 rooms on the first floor with Micropelt thermostatic valves. The building automation system with self-powered, wireless thermostatic radiator valves is an easily upgradable, energy-efficient solution for existing buildings which can cut heating costs by as much as 30 percent.

Benefits for both
Incorporating battery-less wireless energy management solutions into hotels can be accomplished without the costs and burden of expensive, disruptive installations. Wireless systems can be deployed in hotel rooms without needing to take rooms out of commission during installation. All rooms can be pre-configured and fully programmed so that they are ready for easy installation.

The main driver for the implementation of such an energy management solution is economic. Hotels that incorporate HVAC control can expect energy savings of between 20 and 40 percent, which typically represents simple paybacks of less than three years.