As we all look forward to a greener, more sustainable energy future, the promise of hydrogen based fuel cells is certainly one of the most exciting energy technologies on the cusp of mainstream acceptance. Fuel cells were a 10 billion dollar industry in 2019 and that is only growing as the technology continues to become more affordable and more efficient. CPI is excited about this promising technology and even more excited that fuel cell manufacturers are choosing CPI thermal switches as key components in their evolving solutions.
What is a Fuel Cell and How does it Work?A fuel cell is an electrochemical device that combines hydrogen fuel and oxygen to produce electricity, heat and water. Fuel cells operate without combustion, so they are virtually pollution free literally producing water as a by-product. Since the fuel is converted directly to electricity and heat, a fuel cell’s total system efficiency can be much higher than internal combustion engines, extracting much more energy from the same amount of fuel. Some modern fuel cells have an overall efficiency of almost 65% compared only 20% of a gas engine. The fuel cell itself has no moving parts, making it a quiet and reliable source of power. Of course challenges exist with fuel cells because hydrogen is not a naturally occurring element. Hydrogen must be separated from other compounds that contain hydrogen, and breaking these chemical bonds requires energy that is mostly coming from fossil fuel sources. Until renewables provide a much higher percentage of the energy grid, it is fair to say that fuel cells aren’t entirely emissions-free. And of course, in this electrochemical reaction heat is produced along with electricity and water. This heat must be managed carefully as the temperature of the fuel cell is a significant performance changing factor. That’s where CPI comes in. Managing Thermal Performance of Fuel Cells.One CPI thermal switch already seeing use in fuel cells is our AD173 bimetallic thermal switch. This switch is a small form factor switch that can detect temperatures from –18C to 148C with tolerances as tight as 2.8C. The under-clamp mounting tab makes this switch perfect for pipe or exhaust mounting and the small size and custom lead lengths mean it can fit into a tight space. Another feature of the AD series appropriate for fuel cells is the fact that it is hermetically sealed and can be deployed inside or exposed to the elements without issue. The switch is also impervious to shock and vibration for vehicle mounted cells and will not fail even under highly challenging environmental conditions. Controlling the temperature of fuel cell reactions is critical to the overall efficiency of its operation and the AD series of thermal switches has been used for both high and low temperature detection in fuel cells for different monitoring applications. Low Temperature Fuel Cell Detection & PreventionGiven that water is such an important part of fuel cell operation, careful precautions must be take to ensure that the water in a cell is not allowed to freeze. For this our AD series turns out to be a perfect solution as well. Deployed at a 35F set point, our AD series switches have been used to initiate anti-freeze protection extending the useful temperature range of outdoor fuel cells. Our AD series also offers flexible off the shelf mounting options as well as customizable lead lengths. And for those who need something more, our engineering team is able to handle custom features. Please call our team today for a consultation on your Fuel Cell Application. Original content published: www.cpi-nj.com/fuel-cell-thermal-management-by-cpi/ Earlier this year the state of Texas saw one of its most devastating statewide power outages when winter storms rolled through the state and left freezing temperatures behind for weeks. While the vast majority of power was lost due to the failure of so-called thermal sources including coal, natural gas and gas power plants, and nuclear (87% of Texas’ outages were from these sources only %13 from the failure of renewable sources*) , much was made of the failure of renewable sources like solar and wind which in normal circumstances, generate about ¼ of the state’s power.
It turns out that CPI thermal switches can be part of the solution for Texas’ infrastructure improvements, particularly in the area of wind turbines. Wind turbines can be made to work reliably even in extreme weather as they do routinely in Greenland or the Artic regions of Sweden and Finland. Here’s one of the ways we help do that. * Electric Reliability Council of Texas (ERCOT) Thermal Switches for cold detection in WindmillsIn the great Texas freeze of 2021, it was clear that winterization techniques are now a reality to deal with a rapidly changing global climate. In the case of wind turbines, many systems can be protected from cold related failure by used of special anti-freeze fluids, more weatherproof or heated gearboxes not to mention internally heated electronics which can also fail in extreme cold. This is a proven application for CPI thermal switches which have been used in power grid applications, windmills, and shipboard military equipment to do exactly this: accurately detect cold conditions to turn on systems that heat things up! CPI’s hermetically sealed M1 Thermal SwitchCommonly used in these applications is our M1001 Plugstat Thermal Switch. This switch is a hermetically sealed, bimetal thermal detector rated for accurate switching down to -17 degrees C. It is slow make and break, providing natural hysteresis against chatter. The technology is a carefully engineered and manufactured thermocouple that has decades of proven operation in the field and in applications all over the world, both hot and cold. In windmill applications there are actually many ways to use this switch to activate heater systems or other fail prevention systems. For example, windmills depend on critical voltage converters to translate the mechanical energy of the turbine to electrical energy. But these converters have a lower limit on the temperature under which they can safely operate. Our switch is used as a cold temperature indicator that the converter controller software reads. If the temperature hits the low temperature set point (in this case -3C) it is a signal that the internal heating system for the voltage converter has failed to turn on. To prevent a failure, our switch sends a signal to raise a fault and shut down the converter. In other applications the same switch closure is used to turn on local heating elements which prevent the gearbox and associated electronics from reaching freezing temperatures which may exceed their ratings. The switch closure can also be used in windmills to enable the flow of antifreeze by turning on pumps and generating alarms when various temperature thresholds are reached. For Hardening the Power Grid – Think CPI Thermal Sensors and Switches.CPI has been evolving its thermal switches for over 50 years until now, where they are arguably the most robust, fool-proof, thermal detectors in the world. When you’re protecting something as important as the power grid, your best choice is to design-in CPI. Call us today for a free engineering consultation on your Thermal Switch Application. Original content published: www.cpi-nj.com/windmills-cpi-thermal-switches/ As electric vehicles begin to change the face of transportation in USA, and the world, the conversation is all about charging the batteries. Charging stations are popping up all over the country. Most of these employ traditional charging cables with compatible connectors and they work well enough for most consumer vehicles.
Wireless charging however, is the next frontier for electric vehicles, especially trucks and busses and other large vehicles for whom cable based charging represents certain challenges. Imagine a time when a self-driving rideshare vehicle automatically pulls over and picks you up and drives passenger after passenger to stops along its route without ever needing to stop to recharge its battery. Instead, power generated by nearby wind and solar sources is delivered wirelessly from the roadway to the vehicle while it is in motion. While some problems still need to be overcome to make this work on a large scale, prototype systems are already deployed across the USA and Canada. CPI is proud to note that we are a component provider to more than one of these kinds of applications. Wireless Charging is Driving a Demand for High Dielectric ComponentsYou can think of wireless vehicle charging as an enhanced version of wireless smartphone charging with one important difference: The power required to generate the required electric field is significantly higher. As the power goes up, a number of additional factors needs to be considered, such as thermal losses and thermal runaway. The higher the inefficiency or distance of the energy transfer, the higher the power requirement, and the greater the heat losses and thermal management required. Another challenge is the extremely powerful electric field generated. Electronic components need to survive in field strengths of up to 5000V, a potential well beyond the range of normal insulators. Some manufacturers leading the development of electronic charging stations are choosing an new variation of CPI SnapStat Thermal Switches for their temperature monitoring solution. AD190B (normally-closed) shown“The high dielectric strength requirement was a customization for us”, notes John Crozier, CPI’s lead application engineer on the project. “With a requirement for survivability up to 5000v we created a custom version of our SnapStat surface mount thermal that used a special material with ultra-high dielectric resistance.” That material, commonly called Ultem, is actually an amorphous polyetherimide thermoplastic know for its tremendous insulating properties. The AD190 High Dielectric Surface Temperature Switch will be mounted directly on the heatsink and have a preprogrammed set point of 90C. The switch is fully rated for dielectric resistance up to 5000 VAC. Because these switches were designed for high reliability, they have a double snap action making them virtually immune to shock and vibration. They are also available with epoxy sealing or glass to metal hermetic sealing for the most demanding applications. Dielectric Switch Applications do not end with Charging StationsManufacturer’s of components for power distribution generally, have a need for switches that survive in high E&M field environments. Development of the “Smart Power Grid” or Smart Grid is an application that is seeing more and more requirements for dielectric hardened thermal detectors like our new AD191. While our thermals are usually used to detect hot thermal runaway conditions at the high end, in one application the switch is being used to activate at the colder edge of its range. In Smart Grid repeaters the AD191 is turning on heaters that prevent other electronic components from getting too cold. Reliable Cold detection is a unique feature of CPI Thermal switches in that they operate down to 0 degrees Fahrenheit. With their high dielectric rating, they are virtually immune to EMI. CPI Thermal Switches – For Standalone Performance Under any ConditionsAnother feature that makes CPI Thermals perfect for applications like wireless charging systems are the fact that it is a standalone detection system: in other words, once a set point is reached switch closure is going to happen, regardless of how fried the rest of your electronics may be. Despite the availability of sophisticated remote sensors and controllers, sometimes there’s nothing better than the reliability and dependability of a well-engineered thermocouple. For more information on CPI Thermal Switches, call our engineering team today. Original content published: www.cpi-nj.com/cpi-custom-thermal-switches-for-high-dielectric-applications/ Food processing and Galley equipment include many components designed to reach high temperatures and stay there for extended periods of time. In this equipment, fire hazards and thermal runaway are key safety concerns. Even food packaging equipment used in production environments that pre-cook and seal food, have stringent requirements for temperature monitoring and fail-safe operation.
In areas like galley kitchens on boats or planes, the stakes are even higher. Fires in these areas can quickly spread and cause catastrophic damage or injury. Better that they never get started in the first place. We can help with that. CPI switches are a standalone solution to Thermal ControlOne key consideration in selecting a thermal sensor for food processing is whether it will function on its own, or does it require a PLC to react to sensor data and provide the right fail safe operation to external relays or systems. The primary tradeoff here is related to both cost, and durability of the overall solution. Thermal sensors in a PLC environment are cheap, but as part of an overall system solution they may not be best solution for critical thermal detection. These sensors are not generally hardened, have limited temperature detection ranges, and require a central computer or logic system to provide the required control, increasing complexity and the number of failure points. CPI has found that the vast majority of OEM’s needing robust thermal safety switching, prefer a hardened standalone thermal sensor. In this scenario, an advanced thermocouple with a fixed set point, provides local switch open/closed behavior, completely independently of any central PLC or computer control. Add to this the fact that our thermal switches cover temperature ranges up 1750F (CPI Rod & Tube Series) which is well beyond the range of any remote sensor. CPI thermal switches are also hardened for survivability in high vibration environments. CPI Thermals come in three varieties: CPI SnapStat (0 – 300F) Using a precisely engineered bimetal snap disc, we actuate a miniature microswitch through a double snap action. Multiple mounting options available. CPI PlugStat (0 – 650F) Contact movement in the PlugStat is achieved by controlling the different expansion rates of 2 fused metals providing tight tolerances and a small differential. CPI Rod & Tube (0 – 1750F) Ideal for use in galley’s or furnace controls to sense or control combustion. Very high temperature sensing with very rapid response time. No matter what temperature range or form factor you choose, all CPI switches are hardened for longest possible lifetime, and extreme durability under adverse environmental conditions. CPI Thermal Switches are also customizable for special mounting considerations like MIL STD bulkhead mounting or custom lead lengths or wiring insulation to achieve better thermal dissipation. We’ve been doing this for over 70 years. Bring us your requirements, we’ll give you a solution that will be the last solution you’ll ever need. Original content published: www.cpi-nj.com/it-gets-hot-in-the-kitchen/ When CPI started making thermal switches for the Military in the 40’s, there really wasn’t any other choice. Thermocouple based switches with variable set-points and various temperature ranges of operation were made using the thermocouple materials of the day, mostly copper, aluminum, and chrome. The concept of a thermocouple had been around for over 100 years but CPI switches of that time stood out because they provided reliable operation over an extended temperature range, in an environmentally hardened package suitable for battlefield conditions. Temperature switch technology has evolved over the last 75 years however, and depending on what you’re trying to do, alternate thermal switching technologies abound. For instance, in applications where smaller temperature differences need to be measured with high accuracy (like from 0-100C at 0.01%), technologies like thermistors, temperature sensors tied to external control systems, or simple resistance thermometers may be more suitable and cost effective. Still, traditional thermal switches have evolved too. The variety of types, and use of metal alloy’s has been informed by discovery, experimentation, and improvements in manufacturing processes. Today’s CPI thermal switches come in three basic types, covering a thermal range from 0 to 1750 degrees Celsius. And as always, CPI switches maintain their hardened design making them unique in the world for their electromechanical endurance, and their survivability. Thermal Switch Applications Perhaps one of the best ways to understand the applications that are better suited for thermal switches vs. sensors is to look at common applications for these switches. Galley Temperature Sensors – Prevention of galley fires is critical on both Navy Ships and around any high temperature professional cooking stations. With flash points over 1000 degrees, these systems usually do not have a controller and so local switching to turn of gas supply or raise an alarm is appropriate. Steel Manufacturing – Thermal Switches are used extensively in the steel and iron industries to monitor temperatures and chemistry throughout the steel making process. Disposable, immersible, type S thermocouples are regularly used in the electric arc furnace process to accurately measure the temperature of steel before tapping. The cooling curve of a small steel sample can be analyzed and used to estimate the carbon content of molten steel. Engine Cooling Fan Control – Thermal Switches are commonly used to locally control cooling fans which prevent engine overheat on everything from generators to jet engines. Gas Shut-Off – In systems using pilot lights, a thermal switch will often sense the presence of the pilot and shut off gas flow if the pilot should go out for any reason. Oil Refining – Control of temperature in the oil refinery requires accurate and hardened thermal sensing for many fail-safe systems in the refining process. Avionics Bay Over-Temp – In both commercial and military aircraft, ambient temperature in the avionics bay can reach well over 100 degrees C as components heat up, contributing to early system failure. Thermal switches are used here to economically activate cooling systems. CPI Thermal SwitchesOur three lines of thermal switches include the following.
All switches are characterized by flexible mounting options, highly accurate and programmable set points, and hardened construction for extreme environments. For more information on CPI thermal switches, please contact our engineering team today. Original content posted on https://www.cpi-nj.com/blog/when-to-use-a-real-thermal-switch-not-a-sensor/ |
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