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SENSORS : ESSENTIAL COMPONENTS IN COUNTLESS APPLICATIONS
By Benjamin Brits
When thinking about sensors , their technology , or the function behind these varied devices , one would not particularly realise that they have in fact become a part of everyday living .
Carel Testo
While clients are generally more concerned about aesthetics , function and how much they have to spend , intricacies in the systems of the HVAC & R sector are not top of mind even though it ’ s the little things , like sensors , that play a significant role in short- and long-term savings . Their use in new plants today is a given , and their addition to old plants with a little adjustment can generate immediate results in savings . Sensors have , in some instances , been referred to as pervasive in the human context . They are embedded within so many devices and tallying these up could open your mind to the reasoning for statements such as this . They are in the computers or laptops we use on a daily basis , in our smartphones , in our watches , electronic appliances , cars , and
Sensors come in a variety of forms and capacities . This image illustrates the types and connectivity .
Humidity control has been linked to various wellness aspects for offices and plays a further role in a number of other applications where the correct humidity is essential for stores goods for example . especially required in our air conditioning and refrigeration systems , to name but a few .
Now although these devices are found extensively across so many applications , one should also consider the fact that without sensors we would not enjoy many of the products , processes , or conveniences we consider critical to our modern-day existence , not to mention that automation could not exist . Improvement in system efficiency is also made possible through sensors , their continual development and improvement .
It would be safe to say that for any engineering concept , a sensor already exists . For the HVAC & R environment , these would include sensors for temperature , pressure , humidity , indoor air quality , smoke or gas detection , flow rates , motion , consumption and even occupancy . Further , sensors in this field would be broken down into categories such as sensitivity , range of measurement , degree of accuracy , response time and importantly output that would include , in simple terms , a ‘ monitor only ’ or ‘ read and perform action ’.
Any sensor works by acquiring a physical input and converting this into a signal suitable for a measuring or processing task through detecting differences in quantity . Today , this ‘ signal ’ is more commonly output in an electrical form and could also be wired to a controller , be part of a network , or even enabled to deliver that signal via wireless or Bluetooth options . Each type of sensor would also have a different means of ‘ translating ’ the input to an output – for example internally you would see components that react under pressure or particular heat range , simple different metal strips / plates that react differently to the input , resistive materials , or particular chemical reaction .
Looking back to where sensors originated , this spans many decades and was directly linked to the progress observed in each particular industry sector . Pressure sensors were invented in the mid-1800s owing to a number of accidents involving steam units , thermal sensors are shown to have been developed on a large-
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RACA Journal I January 2022 www . hvacronline . co . za