When Willis Carrier designed a system of fans, ducts and perforated pipes, which became the first modern electric air conditioner (AC) in 1902 (120 years ago), sensing was not part of the bill of materials.
Devon Brock, Manager of Product Knowledge and Training, Sensors Group at TE Connectivity provides some insight into subsequent AC systems. He says, “Originally the control systems were quite crude and typically had more switches than sensors.” In fact, bi-metal temperature switches and pressure switches are still used to some extent.
“Today, the more sophisticated systems require more sensors and different types of sensors besides just pressure and temperature,” says Brock. “More sensors to check the environment but also more sensors to actually run the system.”
In addition to humidity, gas sensing for CO2 contributes to environment sensing. In today’s heating, ventilation and air-conditioning (HVAC) systems, sensors play an integral role in helping to not only maintain a comfortable and safe indoor climate, but also to enable reduced downtime, improved productivity, lower maintenance and operating costs, as well as improved sustainability.TE Connectivity’s HTU31 Humidity and Temperature Combination Sensor.
Increasing HVAC complexity and the resulting increased use of sensors occurs as the end use changes from a home (residential) to a commercial and, finally, enterprise-level systems. At the higher end, the HVAC system is more tightly integrated into the overall environment.
“Building automation systems are very sophisticated,” observes Paul Sittard, Account Manager, Sensors Group at TE Connectivity. “You are looking at everything.”
This includes sensing for vibration monitoring and more, similar to monitoring and maintenance in automated factories in the Industrial Internet of Things (IIoT).
According to the U.S. Energy Information Administration (EIA), “When electrical system energy losses are included, the residential and commercial sectors accounted for about 22% and 18% respectively—40% combined—of total U.S. energy consumption in 2020.”
Part 2 will go into greater details in today’s HVAC sensors.