Future Electronics — How Thermal Pixel Array Sensors Support New Building Automation

Loft and wall insulation, double glazing, and LED lighting have together greatly reduced the thermal and electrical energy consumption of residential and commercial buildings in the past 50 years. But despite these advances, building operations still suffer from various inefficiencies.

For instance, under-utilized space means that many buildings are larger than they need to be for the number of people occupying them, especially since the Covid-19 pandemic has extended the practise of working from home. Energy continues to be wasted because spaces are lit and heated even when unoccupied. And conventional technologies for heating indoor space ineffectively deliver warmth and comfort to the users of the space.

The root cause of this inefficiency has until now been the weak link in all building control systems: people. It is unfortunately true that human beings routinely leave lights on when they leave a room, book meeting rooms and then fail to show up for the meeting, and set the target temperature too high on entering a cold room.

This implies that, if buildings could be made more self-regulating, both the planet and building operators would benefit: enhanced building automation would cut the greenhouse gas emissions produced by buildings’ heating, ventilation and lighting systems, while also cutting running costs.

Progress towards this desirable outcome is now being accelerated by three concurrent trends. First, regulations applied worldwide to commercial and domestic buildings are tightening requirements to meet minimum standards for parameters such as energy efficiency and indoor air quality.

Second, organizations worldwide which own or operate office buildings are planning for a post-pandemic world in which fewer workers occupy offices and more work from home.

Third, the commercialization of mainstream, affordable semiconductor technology supporting rich data-driven Artificial Intelligence (AI) is enabling machines to perform decision-making operations that call for human-like interpretation of complex and ambiguous data sets such as image files.

As a result, OEMs which make products such as Heating, Ventilation and Air-Conditioning (HVAC) equipment, security and access control devices, lighting controls, and building automation systems are eagerly eyeing the opportunity to take a share of a market which was worth an estimated $75bn in 2020.

Some of the value of next-generation building automation systems will be in the technology for detecting occupancy, for counting people, and for measuring the temperature of indoor spaces. All of these functions can be performed through thermal sensing of infrared radiation.

Here too, advances in technology are enabling new functionality and the more sophisticated operation of systems such as lighting controls, heating controls, and ventilation.

Emergence of Cost-Effective Board-Level Thermal Imager

Remote far-infrared thermal sensing provides an ideal means for detecting objects which emit infrared radiation, across a broad spectrum of wavelengths. Thermal imagers detect part of the heat radiation spectrum, for example between wavelengths of 700nm and 1,300nm. Thermal sensors do not operate in the visible light spectrum, so require no means of illumination and work as effectively in daylight as at night. Since an infrared thermal sensor can measure temperature remotely and accurately, the same device may potentially be used to detect thermally transmissive objects such as human bodies and also to measure surface temperatures.

These functions are of high value in intelligent building automation systems, where they may be used to: