The design and selection of industrial electric heaters must be based on specific operating parameters. Taking a heating unit powered by 380V, 21A single-phase as an example, under specific flow rate and temperature difference conditions, the time required to reach the target temperature is approximately 1.6 minutes. Such data is usually obtained through heat balance calculations, and designers need to make corrections based on medium properties, flow velocity, and heat loss.
Compared with steam heating systems, electric heaters do not require boilers, piping, or condensate recovery devices, resulting in fewer initial investment and maintenance aspects, and are suitable for occasions without a steam source or requiring precise temperature control. Compared with thermal oil heating, electric heating acts directly on the medium or transfers heat through a sheath, with smaller thermal inertia and faster heating response, but operating energy costs are greatly affected by electricity prices. When selecting, it is necessary to weigh initial investment, operating costs, and temperature control accuracy requirements.
Sheathed electric heaters place the heating element inside a metal sheath, suitable for heating flammable, explosive, or scaling-prone media, and are easy to replace and maintain. Immersion electric heaters directly contact the medium, with higher heat transfer efficiency, but are sensitive to medium corrosiveness and scaling. Design and selection personnel should determine the structural form based on medium corrosiveness, scaling tendency, and explosion-proof requirements.
Heating power must meet the heat demand of both startup and steady-state conditions. Startup power is usually higher than steady-state power, and the initial medium temperature, target temperature, and allowable heating time need to be considered. Excessive surface load will cause the sheath surface temperature to be too high, possibly leading to medium decomposition or coking. Therefore, reasonably determining the surface load and sheath material is key. In addition, the impact of supply voltage fluctuations on output power must be calculated, and over-temperature protection and interlock control must be provided.
The DRK-18 industrial electric heater is suitable for heating water, oil, air, and some chemical media, and can be customized according to the medium parameters, flow rate, inlet and outlet temperatures, and explosion-proof grade provided by the user.
