Defective cable heating

First, the working mechanism As we all know, when the power line through the current, the copper will generate a lot of heat loss. As a result, the transmitted power is depleted and weakened. (Copper wire) The smaller the wire diameter and the larger the current that passes, the higher the heat loss. This phenomenon is called "current load overload." In daily life, long-term "current overload" will overload the wire to several hundred degrees of heat, which is the culprit for most fire accidents! Therefore, the state has strict requirements on the power wiring in the concealed works of decoration and resolutely put an end to the emergence of this phenomenon. The working principle of the heating cable is to use the "current load overload" shortcomings, and developed the heating and heating products. It passes the heat conduction between the high-temperature cable line and the ground floor to increase the ground temperature and achieve the effect of ground heating.

Second, the system composition and characteristics "wire coil + insulation board + thermostat" that is formed a floor heating system. Features: Linear high-temperature conduction heating, no infrared radiation heating.

Third, the lack of heating cable 1, the working mechanism is irrational, energy consumption is oddly high (1) The lack of linear heating body In order to achieve the effect of uniform heating on the ground, the heating cable must be coiled under the ground repeatedly. Its purpose is to make the underground line of high-temperature body (cable temperature ≥ 65 °C) into a planar low-temperature body (ground temperature ≤ 40 °C). Therefore, it achieves the same ground heating effect and requires a higher power configuration (power configuration = 180 W/m2). (2) The defect of the loss of the line loss The other disadvantage of the heating cable is the line loss of the electric energy (amount). Since the heating element must exist in a coiled configuration, each additional elbow of the wire increases the loss of power transmission. The principle is like the repeated bending of the water pipe, it must increase the water pressure. The above two points have determined that the actual energy consumption of heating cables remains high. There are examples to show that in Shanghai, a high-end apartment of 165 square meters, after installing a heating cable in 2005, its electricity bill was more than 2,000 yuan in October. After cooling down in December, its electricity bill was as high as 12,000 yuan.

2. The reliability of the system control system is poor Because the heating cable itself is in the energized state, the temperature of the electric wire will continue to increase (until melting). Therefore, an external temperature control system must be used to prevent the high temperature of the cable and the high temperature fuse. Therefore, all temperature controllers configured for heating cables are designed with two temperature control systems. One is to control the indoor ambient temperature, and the other is to control the cable temperature (to prevent the cable from overheating). When one of the two temperature control systems meets the set requirements, the thermostat cuts off the power and the heating cable stops working. This kind of control mode of the heating cable makes the safety of the whole system totally depend on the quality of the thermostat that is matched with it (not the product itself). Once the matching thermostat fails, the entire system must crash. If the floor covering material is not flame-retardant, it will result in irreparable and large loss to the user.

3, the surface of the cement coating requirements The nature of high-heating cables is the wire. It is conceivable that a single high-temperature line at 65°C (or even higher) underground will bake concrete like a knife during work. And what cement is afraid of is precisely the high temperature. High temperatures will greatly weaken the strength of the cement. General Cement Subgrade In order to prevent summer sun exposure (where the surface temperature reaches 70°C) causing cracks in the road surface, it is necessary to lay high-grade cement with a thickness of at least 14 cm. This kind of laying conditions is difficult to achieve in ordinary residential houses. At the same time, the enormous gravitational force generated by the cracking of the cement layer under the ground will cause cracks in the ground tiles, marble, and other materials. In addition, high-temperature cable insulation damage is also very serious. Due to the high temperature of the cable, the thermal insulation plate that is close to the edge of the cable will be gradually melted. At this point, the cable will be diffused into the insulation board and gradually separated from the cement layer. Because of the reduction of the contact surface between the cable line and the cement layer, the amount of heat conducted by the cable line to the ground is also gradually reduced, thereby affecting the heating effect of the floor heating and increasing the energy consumption.