4 Primary Types of PTC Heating Elements Explained
Positive temperature coefficient, PTC heaters
PTC ceramic heating elements are used throughout our industrial economy. Their compact size, efficient heat transfer, reliability, and ability to self-control the amount of heat produced are highly valued. PTC heating elements are found in our homes, cars, trucks, trains, planes, ships, medical equipment, industry & manufacturing.
The small PTC ceramic materials or disks, specially made for specific temperatures, are encased in materials that facilitate thermal energy transfer for this compact source. The small ceramic stones are doped with barium nitrate during manufacturing for specified temperatures. These set-point temperatures are what make these elements unique in heating applications.
PTC Ceramic Heating Element
The PTC characteristics of a positive temperature coefficient element control the amount of heat generated by the inverse circuit current relationship. As the temperature increases, the device’s circuit resistance increases rapidly, effectively shutting down current flow preventing overheating. As the temperature decreases, so does the resistance, increasing current until the set-point is again reached. This automated system reduces or eliminates the need for external control systems.
Another characteristic of PTC heaters is they adjust to ambient temperature. As the ambient temperature, the amount of current that flows through the circuit is reduced. The heater only responds to the difference between its set-point and ambient temperature. Only the current and heat necessary to respond to the difference between the two temperatures.
If the ambient temperature decreases, the heat developed will increase to meet the change required to reach the set point. This built-in temperature control is well suited for outside weather conditions. This self-regulating property makes the PTC elements very energy efficient.
Types of PTC Heating Systems
PTC Air Heater
A PTC air heating system is constructed to transfer heat from the ceramic disc to the air around the device. Typically extruded aluminum fins are to transfer the heat. Often these air devices are referred to as PTC Fin Heaters.
The actual transfer of heat from the fin structure can be accomplished via natural convection. Air that comes into contact with the heated fins will move upward within a cabinet or other container. A convection heater will be mounted at the lowest point so that the heated air will rise to maintain heat transfer.
PTC Fan Heater
A PTC fan heater uses a similar extruded fin or honeycomb structure with a fan to increase the heat transfer rate. The forced air can also be channeled through ductwork or to another location. Fan heaters are used where the heat needs to be transferred to multiple sites or outlets.
You can find these units in large electrical enclosures, trains, automobiles & trucks, cabs, commercial food processes, and similar applications. The PTC fan heating element is often located where power is available, transferring the heated air to another location.
PTC Surface Heater
The PTC surface heater also uses an extruded fin-like component. The fin draws heat away from the ceramic element, transferring it directly to a surface to be heated. The high-density heating of the disc is conducted through the extrusion to a larger area of the surface.
They are sometimes referred to as PTC conductive heaters or flange heaters in that they conduct the heat from the PTC ceramic heating element to the surface to be heated. These element heaters can be found in medical & cosmetic devices, household appliances, and industrial manufacturing. Anywhere a surface needs to be heated but has limited mounting space for generating heat.
PTC Immersion Heater
The immersion heaters are also referred to as conductive heaters. The primary difference from a surface heater is that the ceramic heating element is bounded inside a protective cylinder or similar configuration. These cylindrical devices are manufactured to be inserted through the wall of a vessel whose contents required heating.
Your household water heater is an excellent example of an immersion heater. The heater fits through a hole in the side of the tank bringing the heated surface into direct contact with the water inside.
All PTC heating element manufacturers are NOT created equal.
DBK designs specialized equipment utilizing PTC heating elements to fit a wide variety of applications.
Want to learn more or have a specific application?
DBK USA has experts standing by to answer your questions. Specialists in PTC heating elements and cooling applications can help you select the right components for your application.
Feel free to call our engineers directly at 1-864-607-9047