As with so many modern technology trends, the concept and the reality of cleantech are often two different things. There is ample discussion out in the world about the aspirations of cleantech, but not nearly enough detail on how cleantech principles can be directly applied in practice. This is particularly true in industrial automation and process control arenas, a fact that we here at Whitman Controls see firsthand. From our vantage point, we see ample potential for cleantech-inspired process automation developments in the years to come, starting with applying customized process instrumentation towards cleantech goals.
Let's start with several definitions:
- Cleantech - refers to any technology that reduces environmental impacts compared to its conventional counterparts by providing enhanced energy efficiency, sustainable use of resources, environmental protection, and/or consumption reduction.
- Industrial Processes - any procedural sequence of manufacturing, logistics, material handling, utility, waste, chemical, or energy steps that are utilized at large scales.
- Process Controls - describes a combination of engineering systems and theory to manage, govern, and mitigate actions performed in any industrial process. Most often, process controls combine industrial logic controllers and mechanized devices to automate processes away from needing physical human manipulation.
- Process Instrumentation - these are physical devices that are installed within an industrial process that serve as the 'eyes and ears' of the process control system. Process sensors and instruments measure process parameters in real-time, reporting that data back to the process control system so that the controller can make informed decisions based on real conditions.
How do these various terms all fit together? In short, cleantech principles strive to influence commercial and industrial entities to cut their energy consumption, use sustainable resources, and overall make decisions that directly reduce their organization's environmental impact. Most of the businesses targeted by cleantech are major resource consumers such as manufacturers, logistics providers, or utility providers, all of which utilize industrial processes and process controls. And so, indirectly, cleantech principles demand that industrial processes be improved in terms of efficiency.
Cleantech proponent firms tend to be specialists in software and venture capital domains, not industrial process engineering, which leaves a gap between their aspirations and their ability to coach real-world improvements. To us, this means that it's up to industrial process engineering professionals to translate cleantech interests into real solutions.
Customizing Process Control Sensors to Meet Cleantech Objectives
As a manufacturer of process control instrumentation, we have a unique perspective on how sensors directly serve cleantech objectives in one of three ways:
- Process Variable Selection - by default, most industrial processes are controlled for overall safety, performance, and reliability, but not total efficiency. In many cases, identifying what process variable directly influences system efficiency is the first step in automating towards cleantech principles. For example with a flow-based fluid system, adding pressure control can help minimize pump motor demands.
- Sensor Selection - sensors may not seem very impactful towards cleantech goals since they're just passive measurement devices, but in actuality, sensors can generate tremendous results in three ways: selecting sensors for longer lifespans reduces consumptive replacement; selecting low-power devices reduces direct energy consumption; and selecting sensors with higher specifications and features reduces systemwide energy demands.
- Sensor Customization - once a system variable and sensor profile are selected, additional conservation-focused decisions can be made through customizing the sensor itself. With a given sensor, many features can be customized to tactically achieve the goals of the system with as little energy, material, and waste as possible.
To further expand on the concept of customizing sensors, here are the most common customizable features we provide into cleantech applications:
- Transmitters vs Switches - in many applications, an analog transmitter will provide real-time process feedback across the application's entire range, not just at the switching point, which can allow the process to be more tightly controlled to maximize energy efficiency (as opposed to relying on only a single, worst-case upper limit switch point).
- Compound Sensors - compound sensors combine multiple variable measurements into a single instrument, which directly reduces the quantity of independent sensors, process connections, electrical circuits, and energy-consuming loads needed to control the process. Pressure/vacuum, and pressure/temperature compound sensors are among the most common combinations.
- Material Selections for Longevity - selecting higher grade sensor materials may add a slight cost to the initial purchase price but can pay dividends in adding years to the sensor's lifespan. This directly reduces the amount of materials consumed to purchase replacement sensors over the life of the process.
- Sensor Pigtails - adding pigtails to pressure sensors buffers spikes, micro-variations, and thermal extremes away from the sensor itself. This buffer smooths out sensor readings, reducing false-positives and intermittent switching points as well as protecting the sensor element towards a longer lifespan.
- UL / CSA Listing - third-party UL and CSA approvals are in many ways a formal certification that sensors have been designed and / or tested against internationally recognized safety, performance, efficiency, and reliability standards. Cleantech projects very often require such third-party approvals as assurance of a component's expected performance.
- Quick Disconnects - in a small but powerful way, adding quick disconnect fittings to a sensor can save field installation materials, reducing total material consumption for a given project. When directly wiring sensors to cable or wire runs, often a conduit box, wiring splices, conduit fittings, a strain relief, and wire ties are added at each sensor. When using a field-wireable or molded quick disconnect cable to land on a compatible sensor instead, most of this extra material can be saved.
- Wiring Leads - when quick disconnects are not an option and field wiring is required, customizable wiring leads are the next best option. Sensors can be provided with extended wiring lead lengths that can reach nearby junction points, saving intermediate connecting materials.
Key Considerations when Customizing Process Instrumentation
Customizing sensors is incredibly beneficial towards cleantech goals, but even greater impact can be achieved by zooming out to examine the role of each sensor within the overall process system. Key considerations when thinking about custom process controls at the systemwide level include:
- Direct vs Indirect Sustainability Benefits - a sensor itself may not solve a massive sustainability challenge, but how it's utilized sure might. In this way, buyers may weigh direct and indirect benefits such as not buying the lowest power demand sensor in order to gain higher sensing resolution that translates into tighter variable control and thus lower systemwide energy consumption.
- Sensor Accuracy and Repeatability - every sensor is susceptible to measurement drift at some point, which can lead to poorly controlled, energy inefficient process systems. Buyers should consider a sensor's rated accuracy and repeatability, so that drift-induced inefficiencies can be minimized.
- PID Loop Configuration - configuring a process control loop's PID (proportional, integral, derivative) parameters can be a little bit art, little bit science. Engineers should consider how a sensor's selection and specifications will translate into actual PID loop settings so that over-ramp, deadband, amplified gain, and read errors don't lead to unnecessary energy inefficiencies.
- Control Loop Tuning - further to the above point, engineers must not only configure their control loops appropriate to the sensors selected and systemwide energy demands desired, but also tune these loops to prove out the concept. If a sensor is selected and PID loop configured for energy efficiency, but then is tuned only for performance and not efficiency, the desired sustainability goals are moot.
- Spare Inventory Consolidation - one of the easiest ways to 'buy sustainably' when it comes to sensors (and practically any other MRO product) is to consolidate part numbers, specifications, and customizations so that the number of spares needed in stock is directly reduced. Said another way, the fewer sensor model numbers used in a plant, the fewer spares needed on the shelf.
As a veteran-owned small business, Whitman Controls is dedicated to supplying premium quality, reliable, technologically advanced instrumentation for use in nearly any application. Our Bristol, CT manufacturing facility embodies over 40 years of engineering, fabrication, and customer service expertise, serving both end-user and manufacturing customers nationwide through direct and distribution channels. Our values drive us to provide the highest level of servant partnership that you can find. To discuss your applications or to learn more about our capabilities, please contact us at (800) 233-4401, via email at [email protected], or online at www.whitmancontrols.com.
