Issue link: https://te.mouser.com/i/1478955
TE CONNECTIVITY SENSORS / WHITE PAPER Making HVAC Systems More Efficient and Reliable with Sensors 4 Reliable Pressure Sensing for Advancing HVAC With an increasing adoption of IIoT, Cloud, and wireless solutions, sensors must be designed with ruggedness, flexibility, and connectivity in mind. For heat pump applications, sensors must operate in extreme conditions while providing long-term reliable data. For example, TE's board mount differential (SM7000, SM8000, and HCLA) and board mount (LMI and LHD) microflow pressure sensors are immune to dust and fumes and provide excellent long-term stability. For applications that require high precision and extended measuring range, the TE LHD sensor provides this functionality in a single component. This pressure sensor measures pressure over a wide range of -5,000 Pa to +5,000 Pa with sub-pascal accuracy. All the LDE/LME/LMI sensors are based on a silicon sensor chip that is only about 4 mm 2 (0.006 in 2 ) in size. The sensor's design contains a micro-flow channel that provides a very high pneumatic impedance of up to 200,000 Pa/(ml/s), which is up to 1000 times higher than comparable sensors. This miniaturized flow channel reduces the gas flow through the sensor which offers many advantages in dusty and humid environments as well as when using long connection tubes or filters. For high pressure applications, TE's M3200 transducers come with a range of threaded pressure port and connector options with standard pressure ranges available from 100 to 5,000 psi or 7 to 350bar. The M3200 is designed for modularity, accuracy, and high-performance signal processing. Additionally, the M3200 is available with a variety of analog outputs including mV, 0-5V, 0-10V and 4-20mA. The M3200 is also available with an I 2 C digital output. Dependable Temperature Sensing in HVAC Applications Temperature sensors follow many of the same trends covered in pressure sensing: Reliability, accuracy, ease of installation, flexibility, etc. An example of this in temperature sensors is the single insulated TPE OM (Thermoplastic elastomer overmolded) probe by TE. With an operating range of -35°C to +105°C and its IP67 rating this NTC thermistor assembly offers multiple connector options as well as customizable accuracies and base resistance value. The TPE overmold design is sealed against moisture and is designed to deliver reliable, accurate temperature monitoring for both heating and cooling applications. Typically, OEMs look for sensor manufacturers with the broadest range of temperature sensing products available. For HVAC temperature sensors, there are many types of technologies in use including NTC thermistor, platinum and nickel RTDs, digital temperature sensors, thermocouples and thermopile elements. There are some tradeoffs between accuracy, time response, moisture resistance, cost, and other parameters within the different temperature technologies. Sensor assemblies for HVAC applications come in a wide variety of options designed to measure surface or air temperatures or as immersion sensor designed to measure liquid temperature. These sensors must be in contact with the medium to be measured while remote or non-contact temperature sensors like thermopiles can monitor temperature from a distance. While temperature, pressure and humidity sensors are the most common sensors found in HVAC and refrigeration applications, there is also an increasing use of sensors for vibration, liquid level, fluid property and position. Vibration and Position to Advancing HVAC Solutions HVAC equipment and systems will typically contain several motors, compressors and other machinery that rotates or moves. Vibration sensors can detect an array of issues common with these types of equipment including worn bearings, imbalance, misalignment, and others that can reduce system efficiencies and potentially cause the system to fail altogether. TE manufactures both board mounted vibration sensors as well as packaged vibration sensors and is also releasing a family of wireless vibration sensor products. The 820M1-0050 is a board mount accelerometer that is available in ranges from +\- 25g to ±500g dynamic ranges and features a flat frequency response up to >10kHz. The TE model 8911 wireless accelerometer combines a sensor, data collector, digital signal processor, and radio into one compact, battery-operated device that measures both vibration and temperature data. The model 8911 incorporates a piezo-electric accelerometer which offers a wide bandwidth to >10kHz, outstanding measurement resolution and superior long-term stability. On the position side, key applications include feedback for valves and actuators, motor feedback as well as building damper feedback and control. TE's position sensing technologies include a range linear variable differential transformer or LVDT sensors which are suitable for detecting very small linear displacements in very demanding environments. TE also has an anisotropic magnetoresistive (AMR) line of rotary and linear position sensing products that is well suited for noisy, dirty industrial environments and provides reliable accurate non-contact position sensing.