Basic knowledge of electric heat tracing

Principle of electric heating

Electric heating is a heating method that uses electrical energy to generate heat. Its core principle is that when current passes through the conductive material in the electric heating tape or other electric heating equipment, according to Joule's law, the electrical energy is converted into thermal energy, thereby heating the pipes and equipment that need heating.

Advantages of electric heating

1. Energy saving

(1) Heat dissipation area: Electric heating products are generally small in size and will not change the shape of the pipeline insulation layer when laid. Steam or hot water heating pipes will expand the heat dissipation area of ​​the insulation layer and increase heat loss.

(2) Heat exchange efficiency: There is only line contact between the steam or hot water heating pipe and the process pipeline, and the heat exchange efficiency is generally 40% - 60%; electric heating products are flat and can form a wider heat exchange surface with the help of aluminum tape, and the heat exchange rate is as high as 90% - 96%.

(3) Overheat compensation: When steam or hot water heating is used, in order to ensure the temperature at the far point of the pipeline and consider the heat loss and leakage along the way, overheat compensation must be performed at the near point; electric heating does not require overheat compensation because it releases heat evenly along the entire length of the line.

(4) Heat energy transmission loss: The heat energy transmission loss of steam and hot water is much greater than the power transmission loss. When the heated pipe is far from the heat source, the steam or hot water will lose a lot along the line, while the power transmission loss is less.

(5) Temperature control: The ideal heating pipeline requires the heating amount to change with the temperature throughout the year or even every day and night. Electric heating can achieve the required heat by strictly tracking the temperature through the temperature control system, but it is extremely difficult to guarantee steam or hot water. Therefore, electric heating can not only save energy but also ensure process requirements for some process pipelines with strict temperature control requirements.

2. Save steel

Steam or hot water heating pipes are usually double pipes, one for the return and one for the return. Together with the accompanied pipe, there are three pipes. Electric heating can eliminate the second heating steel pipe, thus saving steel resources.

3. Save high-quality water

Steam or hot water heating uses a boiler, and its standard water volume needs to be replenished by 5% - 10% every day, and the water quality must be treated; while electric heating does not require water, which can show its advantages in areas without water or with poor water quality.

4. Reduce costs

(1) Design: small design workload.

(2) Construction: simple construction and short cycle.

(3) Maintenance: convenient maintenance and small daily maintenance workload.

Installation points and precautions for electric heating

1. Installation points

Sufficient length: Measure the electric heating tape of sufficient length according to the length of the pipe part that needs to be insulated, and leave about 20 cm longer for wiring.

2. Installation precautions

(1) Horizontal pipeline laying: When laying horizontal pipes in parallel, ensure that the electric heating tape is close to the bottom of the pipe, so that heat can be transferred more effectively during operation and heat loss can be reduced.

(2) Antifreeze sensor installation: The antifreeze sensor should be installed on the upper part of the pipe. The antifreeze sensor should not be directly in contact with the electric heating tape, otherwise the actual temperature of the pipe cannot be accurately detected. When using other laying methods, pay attention to the installation position of the antifreeze sensor. It is best to place it at the lowest point of the pipe temperature.

(3) Leakage protection: In addition to installing intelligent instruments to control the operation of the electric heating tape, when using the electric heating tape alone for antifreeze, a leakage protection device must be installed at the power input end, and an ordinary three-pin plug cannot be used directly. The grounding protection wire must be reliably connected to the pipe where the electric heating tape is laid.

4. Application fields of electric heating

Electric heating is widely used in the field of civil buildings, mainly in electric heating, hot water heating and insulation, anti-condensation and anti-freezing of fire water pipes and water supply and drainage pipes, and ice and snow melting of gutter roofs and slopes. It is also used in the anti-freezing and insulation of industrial wastewater discharge pipes to ensure that wastewater can be purified and discharged normally in winter.

In short, as an effective heating method, electric heating plays an important role in many fields with its own advantages. Its basic knowledge covers principles, advantages, installation and application. With the continuous development of technology, the application prospects of electric heating will be broader.