PTC electric heating element is also called positive temperature coefficient thermistor. One of its most basic characteristics is automatic constant temperature heating, and its heating temperature does not change with the fluctuation of ambient temperature and voltage. When the temperature rises to a certain value, the resistance value of PTC electric heating element will rise sharply, which will make the working current drop sharply and the temperature drop. When the working temperature drops further, the resistance value of PTC electric heating element will drop sharply, the working current will rise sharply and the working temperature will rise to a certain point. The selection of temperature can be set at will during the production of PTC electric heating element according to the use requirements.
PTC electric heating element is a kind of barium titanate ceramic material. It is made by doping dozens of trace elements and calcining at over 1000 ℃, and it is semiconducting and has positive temperature resistance—— Due to its ceramic body, it has the characteristics of corrosion resistance, long service life (up to tens of thousands of hours), stable performance, and high heat conversion efficiency (up to 98%) compared with other electric heating elements. When the temperature of PTC electric heating element is further increased under the influence of some factors, the resistance value of the electric heating element will increase exponentially, so that it is close to the insulator, so that the PTC electric heating element itself will automatically cut off the current and make the temperature fall back, which makes the PTC electric heating element not generate overheating phenomenon and has considerable safety. Generally, the log (Rmax / Rmin) of PTC heating element is greater than 3.
PTC electric heater also has the characteristics of small volume and high power, so when it is applied to window air conditioner, on the basis of the original single cooling window air conditioner, the original structure is kept unchanged, and only PTC electric heater is added to the iron plate at the back of the single cooling evaporator (located at the beginning of the air duct). During heating, under the action of centrifugal fan, preheat air is brought out from the grid, so that when PTC electric heating device is used as heat source, the compressor does not work, forming the indoor air circulation (internal circulation).