What are the disadvantages of using electric auxiliary heating for air conditioning?
Classification of electric auxiliary heating devices:
Electric heaters used in air conditioners are mainly nickel-chromium alloy wire electric heating tubes and ceramic PTC heaters.
1. Electric heating tube and components; (cabinet machine)
2. PTC electric heater and components. (Split) Electric heating tube and components:
Everyone also comes into contact with electric heating tubes in daily life, such as: the heating tube in the electric kettle, and the most used "heating quickly" when going to school and living in school. The electric heating tube we are talking about is applied to the air conditioner, the principle is roughly the same but the structure is different.
Daily-use tubular electric heater: use a metal tube (usually stainless steel tube) as the shell, alloy heating wire as the heating element, lead rods at one or both ends, and fill the metal tube with dense magnesium oxide powder insulation medium to fix the heat Body heating element. (Of course, we definitely cannot directly assemble the electric heating tube in the air conditioner, and generally assemble it into components first).
Daily-use tubular electric heating components refer to one or more seamless steel pipes or corrugated sheets of the same material wrapped on seamless pipes, resettable bimetallic thermostats, thermal fuses, mounting brackets and connecting wires, etc. Composition, electric heating device with double thermal protection function.
Uses: Used in heating and cooling air conditioners to supplement the heat during heating; mainly used in cabinets and embedded air conditioners. The heating pipe should be equipped with double temperature protection according to the requirements of the national standard. When selecting an electric heating tube, in addition to meeting the structural size and power requirements, the surface load and surface temperature should also be reasonably selected.
Electric heating tube assembly structure:
Electric heating tube: constant power, fixed resistance; (Generally, a single camera consists of two electric heating tubes with a power of 1050W in series, and a three-camera consists of three electric heating tubes with a power of 750W in series);
Thermostat: A temperature-sensitive device with a fixed operating temperature that, during normal operation, keeps the controlled temperature between certain limits by automatically switching on or off the circuit. (On the signal line group, the signal is fed back to the electric control when the temperature rises) 70°C.
Thermal fuse: When the temperature reaches the set temperature, the thermal protection element can automatically cut off the power supply and cannot be reset. (on power cord set) 144°C.
There are also some assembly parts, such as: (horizontal and vertical) brackets, wire groups, wire clips, heat insulation pads, etc.
Assembly and working principle:
The electric heating tube assembly is generally assembled on the evaporator of the cabinet machine, plus a protective cover.
When working, the indoor wind wheel makes the indoor air blow out from the air outlet through the evaporator and the electric heating tube, and takes away the heat on the surface of the evaporator and the electric heating tube to achieve the heating effect. The principle is similar to the hair dryer commonly used at home