Issue link: https://te.mouser.com/i/1478955
TE CONNECTIVITY SENSORS / WHITE PAPER Making HVAC Systems More Efficient and Reliable with Sensors 3 only controlling the temperature of a large area, possibly multiple rooms, without the ability to control subsystems or other environmental aspects such as air quality. Today, advanced technology makes it more cost-effective and easier to scale electronic devices and methods to create subsystems and more precise controls. Reliable sensors are driving HVAC trends including advanced and efficient heating and cooling, humidity control, variable refrigerant flow, variable speed motors and blowers, and electronic expansion valves. Today's sensors operate over a wide range of conditions with increased reliability, better accuracy, and little to no drift. Not only are building owners able to control temperatures, but they're able to control the humidity levels and airflow, as well. Most people are aware of how humidity can affect personal comfort but controlling humidity in HVAC systems is important for other reasons as well. Improved HVAC and Health with Humidity Sensing While cooling systems inherently extract humidity from the air, these systems are only effective when cooling is needed. Additionally, if air becomes too dry that can lead to other problems that include eye strain, vocal strain, allergies, asthma, employee performance, mental acuity, and perceived comfort ("humidex"). Research also shows links between low humidity and the increase of flu transmission. Studies show that infection rates for influenza are five times greater in dry air with 7 to 23% relative humidity (RH) than at 43% RH. Ideal humidity levels for people are between 30 to 50%. To provide the best indoor environment, modern HVAC systems include specific components, such as sensors, that monitor and control humidification and dehumidification. The Role of Humidity on Buildings and Inventory Another problem associated with dry air or low humidity levels is the increased risk of electro-static discharge (ESD) for electronics and negative effects on hygroscopic materials, such as paper, plastic, glue, leather, paint, and wood. Humidity monitoring and control can prevent cracking, dry rot, gluing failure, warping, and other effects. Humidity sensors play an integral role in modern HVAC systems to improve performance, reduce energy consumption, and increase safety. In industrial environments where employee comfort and productivity is important and where material moisture levels can effect performance or quality, humidity monitoring and control should be considered. There are three main types of humidity sensors which are defined around what approach is used to sense humidity and deliver an electrical signal that can be used to establish the value. The three types include capacitive, resistive, and thermal conductivity technologies with each technology having advantages and disadvantages. TE manufactures humidity sensors utilizing a special capacitive based technology that provides stable readings over time and can detect a wide range in relative humidity and also provides near linearity with signal amplitude over the range of humidity. TE offers humidity sensing products ranging from board mountable components to PCB modules to humidity sensor assemblies that include both analog and digital solutions. Additionally, TE delivers… • Full RH range from 0 to 100% • Quick response and recovery times • Minimal hysteresis • Self-diagnostic capabilities • High accuracy • Low power consumption • Ratings for full water immersion Combination Sensing Products For OEMs designing HVAC solutions, reducing SKUs, assemblies, and simplifying installations are also important. Companies offering manufacturing capabilities for combining sensor products can help OEMs deliver significant value to clients. For example, the HTU31 by TE, is a 2.5 x 2.5 x 0.9 mm package, individually calibrated, high accuracy sensor that is serialized for traceability and provides ±2% accuracy for relative humidity and ±0.2°C for temperature. It comes in a compact 6-pin DFN package, provides a fast response time, and has a typical power consumption of only 3.78µW. The sensors are available in both a digital Inter-integrated Circuit (I 2 C) format with a configurable address as well as a model with an analog output 0.5-4.5V output.