The Power Behind Smart Buildings and Cities

IoT technology connects thousands of sensors, enables real-time data collection and analysis, and makes buildings smarter and more efficient. Still, power is a challenge.

The batteries of any smart device are costly, and the constant replacement of batteries within large smart buildings has a high price tag in unit cost and maintenance cost. We’ve made strides with technologies that extend the battery life of connected devices. Battery-extending technology that is making a difference includes:

• Bluetooth with 4x the range, 2x the speed, and 8x the bandwidth of its predecessors
• Wireless IoT sensors can be installed, and networks expanded without running cables or opening walls
• Leveraging low-power radio and on-demand wakeup enables connected devices to operate with minimal power and listen for incoming transmissions while still in a low-power state. This provides lower power consumption and allows battery-powered devices to require battery replacement as seldom as 10 years or even never.

Although smart buildings are becoming more efficient, disposable batteries are still problematic. Powering tens of thousands of building devices is costly, but the materials used are environmentally harmful when disposed of, making a no-batteries-at-all approach even more attractive.

As the number of IoT and smart building applications multiply, the implementation of battery-free solutions based on energy harvesting will eventually support connectivity more sustainably. Energy harvesting-powered wireless sensors enable existing and new structures to comply with Industry 4.0. These wireless sensors allow autonomous control of such important operating conditions as temperature, CO₂ and humidity, and optimize overall building efficiency. However, a downside is that wireless sensors in autonomous buildings need a separate and reliable power source for each sensor.

Power delivery can be improved using small form-factor dye-sensitized solar cells (DSSCs) addressing a wide range of building management system (BMS) sensors. Light to power the cells can be delivered from both artificial lighting and ambient sunlight. Small form factor energy harvesters will require DC-DC conversion to increase the source voltage to a standard value used in analog and digital sensor interface circuitry, such as 3 V and 5 V.

Energy-harvesting radio frequency (RF) sensors eliminate the need for batteries and copper wiring, both energy-intensive products, sourcing their energy from movement, light, and temperature differentials.

There are also size constraints for wireless sensor systems and energy harvesting sources generating low-power levels. Given this reality, power conversion efficiency and energy management circuitry between the source and output load significantly impact output power delivery.

While progress has been made in improving the efficiency of individual energy harvesting system blocks, more needs to be done to achieve the synergies necessary to optimize the performance of several combined blocks.

Combining self-powered radio sensors, which harvest energy from light, with Wi-Fi access points allows collected sensor data to be sent to the cloud for analysis with the help of IoT software. Along with ease of installation and maintenance, battery-free and wireless radio sensors can help owners benefit from turning their new or existing offices into smart, flexible, and safe workspaces.

It’s been said that the pandemic will result in employees continuing to work remotely, leaving buildings, however smart they may be, somewhat empty. The jury is out on whether fewer people will occupy smart buildings and work remotely or be called back to work onsite as companies are increasingly calling their employees back to a brick-and-mortar environment. Employees on site want a comfortable, healthy, and safe environment. This is somewhat tricky, considering buildings are responsible for approximately 40% of global CO₂ emissions (Architecture 2030).