Self-powered wireless switches, sensors, and controls are being utilized in a wide range of building automation and industrial applications, leveraging energy harvesting wireless technology to cut installation costs and enable efficient use of energy. The use of energy harvesting technology, especially for wireless monitoring and control, is a key feature because it both lowers system maintenance requirements and opens up new application possibilities.
According to Jim O'Callaghan, president of EnOcean, energy harvesting wireless technology provides a viable solution because where sensor data resides, there is also sufficient ambient energy to power sensors and radio communications. Different types of harvestable energy include motion, indoor light, and temperature differentials. These sources provide sufficient energy to transmit and receive radio signals between wireless switches, sensors, actuators, and controllers, sustaining vital communications within an energy management system. Instead of batteries, miniaturized energy converters generate power for the wirelessly communicating devices.
Typical energy harvesting wireless applications for the home include both lighting and HVAC. Battery-less wireless switches can control lighting/shading, and outdoor light sensors automatically match lighting to daylight. Occupancy sensor adjusts temperature and turns off lights when a room is not in use. Room temperature sensors offer minimal energy consumption and maximum comfort.
(Source: EnOcean Inc.)
One key application area for this technology is building automation. The combination of wireless and battery-less technologies significantly eases energy monitoring and control in buildings with only minor intervention into the existing systems. The wireless devices are highly flexible to install, which results in individual components, wall switches, sensors, and relay receivers that can be easily networked to form an intelligent system without complex cabling. In addition, dispensing with batteries eliminates the burdensome need to maintain the devices’ energy supply in a regular time period, which can be up to a year.
Wireless technology supports a wide variety of battery-less and maintenance-free sensors that can be freely positioned including switches next to doors, temperature sensors at the workplace, and motion detectors in the middle of rooms. Compared to a wired solution, buildings can be planned, constructed, and operated with greater flexibility and at lower cost. Sensors harvest energy from their surroundings -- tiny changes in movement, pressure, light, temperature, or vibration are all that is needed.
According to O'Callaghan, a second area where wireless technology is opening up new applications is in alarm systems, due to reliability requirements that are a lot more stringent compared to lighting controls. A system failure not only means a malfunction but can cause much more serious consequences for other systems that depend upon the equipment being monitored. It’s a fact that more malfunctions are caused by battery failures than by the electronics, especially in large systems. Energy harvesting overcomes this issue.
Water detectors, for example, use miniaturized solar cells or motion energy converters to power wireless signals to report water leaks in areas such as washing machines, or in the kitchen or bathroom. With an EnOcean device, the wireless signal immediately sends leakage information to a gateway controller or directly to a valve, causing the main water pipeline or affected supply line to be shut off. A notification can also be sent to the user’s smartphone or tablet.
EnOcean has developed a wireless standard optimized for solutions with ultra-low-power consumption and energy harvesting (ISO/IEC 14543-3-10) that has been ratified by the International Electrotechnical Commission (IEC). According to the company, it is the first and only wireless standard that is also optimized for energy harvesting solutions and self-powered wireless technology.
The standard is geared to wireless sensors and wireless sensor networks with ultra-low-power consumption. It also includes sensor networks that utilize energy harvesting technology to draw energy from their surroundings using motion, light, or temperature differences. This principle enables electronic control systems to be used that work independently of an external power supply. The company has been producing and marketing maintenance-free wireless sensor solutions for use in building and industrial automation for more than 10 years.