PTC Fan Heating Improves Efficiency
New PTC ceramic heating elements improve the efficiency of typical resistive heating elements used in applications where electrical forced-air heating is required. The PTC, Positive Temperature Coefficient, the heating element is built into extruded aluminum profiles combined with a fan to effectively transfer heat quickly to an adjoining space. Aluminum profiles are designed for optimal heat transfer with the forced air across the fins.
Efficient Transfer of Energy
In any heating application, some form of energy, electrical, gas, oil, or even hydropower is being converted into heat. The energy of one is converted to heat energy which in turn raises the temperature of the adjoining air or physical object to bring both into equilibrium.
A PTC fan heating system converts electrical energy through the resistive element to heat which transfers very effectively to the aluminum housing. The aluminum housing is designed to radiate the heat to the air moving across its surfaces. The heated air is directed by the fan to the targeted area. The heated air then transfers the heat to the cooler spaces until the surfaces, including human skin, reach equilibrium with the air. Due to the compact size of these heating elements and power density, the energy transfer is more efficient than many other types of heating elements. The PTC elements draw more power initially due to lower resistance and heat faster but lower power as the element reaches equilibrium with the adjoining space.
PTC elements are valued because of the relationship between temperature and the resistance of the circuit. As the temperature increases the resistance of the circuit increases. This relationship is described as a Positive Temperature Coefficient.
More importantly, there is no risk of overheating due to the characteristics of the positive temperature coefficient PTC heaters. The fan heaters have a set power input and self-limiting temperature.
Applications for PTC Element Fan Heating
Electrical Cabinets & Enclosures
Hair dyers are a common device that illustrates how PTC fan heater works. There is an actual patent on utilizing PTC heater in a hairdryer. The PTC heating element prevents the dryer from overheating but also allows it to reach the desired temperature quickly. The resistance in the circuit is lower at start-up allowing more current to flow through the device and heat faster. As it approaches the set temperature the resistance increase slowing the current and the rate of temperature change.
Condensation prevention is a more typical industrial application. Preventing condensation is important in cabinets and enclosures exposed to the weather and elements. In electrical enclosures that don’t lend themselves to convection heating fan heating is the alternative solution. The unique nature of a PTC air heater is ideal for these applications. The element adjusts heating based on ambient temperature preventing condensation from forming with temperature change. Hydrostats are often included in the circuitry to detect humidity conditions. PTC fan heaters are available in 5-40 wattages for tight spaces. DBK USA heaters come prewired with a 35mm DIN rail clip for mounting. There is also a high power 300- 800 W 115 V or 230 V version with screw terminals for easy wiring.
Windmills, gas and oil pipelines, and other remote equipment exposed to the elements are examples of where PTC fan heaters are used to heat cabinets or open spaces efficiently. Electric Trains lack the engine heat for passenger compartment heaters and are turning to electrical resistant and PTC fan heating elements to fill the gap and circulate warm air.
Food & Beverage Appliances
Commercial appliances used for food and beverage industries require minimum temperatures in a wide range of applications. Many can use fan-powered PTC heating to ensure heat is distributed over a compartment or wider area maintaining food temperatures.
Benefits of PTC Fan Heating Devices
Self Regulation & Safety
The heaters are designed to prevent the ingress of external solids greater than 12.5 mm such as a human finger! DBK USA heaters are built to IP 20 standards.
PTC heating elements are temperature and current self-regulating. Each PTC ceramic element is manufactured to a specific temperature. Once the device reaches that temperature the inverse nature of the device increases resistance in the circuit to infinity effectively shutting down the circuit.
The temperature is relative to an ambient temperature such that at high ambient temperatures less current flows in the circuit to reach the set-temperature without external controls. The self-regulating nature protects the device from over-temperature and current.
Compact & Custom Sizing for Applications
Traditional heaters require space for electrical resistive heating elements and control circuitry often making them unsuitable for applications with limited space. PTC ceramic elements are embedded into custom-sized aluminum extrusions with fans requiring much less space and often no control circuitry. Fans are integrated with the PTC heating element minimizing the overall space required.
PTC Element Efficiency
Electric heating with PTC elements is more efficient than traditional resistant heaters. The Positive Temperature Coefficient element controls the resistance of the circuit to a specifically designed point. The warmer the element the higher the resistance. The cooler the element the lower the resistance and more current will flow increasing the heat.
These characteristics are unique in that the change in resistance and temperature is relative to ambient temperature. The higher the ambient temperature the higher the resistance will be in the circuit impeding current flow and heating the element slower.
PTC ceramic heating elements with fans support multiple voltages, both DC and AC. Dual voltages are available powering the fan and the heater separately if required. Voltage as low as 12 V, AC, or DC is supported.
High Power Density
These devices have a higher power density than resistive wire heaters. The small size of the PTC ceramic heating elements and the ability to be embedded directly into materials for efficient heat transfer results in concentrated power density.
How do you size a PTC natural convection heating element?
Some PTC heating devices are sized by reference temperature, the maximum temperature of the device before the resistance stops current flow. Some are sized by power output. Max inrush current is defined for each power rating for circuit design purposes. DBK USA has experts standing by to answer your questions. Design engineers can utilize the handing power calculator on our website. Feel free to call our thermal engineering specialists directly at 1-864-607-9047. Go to our resources page for more information on PTC convection heaters.