The Attsu HHE Hybrid is designed to operate flexibly using common fuels (natural gas, LPG, diesel oil, heavy fuel oil, or biogas) and electric steam generation, allowing the plant to switch from one source to the other or to combine both. Whether the mode change is automated depends on the control system configuration (for example, when equipped with a PLC and communication protocols such as Modbus or Profibus).
In operation, the boiler can manage the electric contribution (via special high-temperature resistance elements) within the available range of 5% to 50% of total steam production, using low voltage (400/690 V) or medium voltage (4160/6600 V) depending on the installation. When demand exceeds the share assigned to the electric section, or when an additional response is required, the system can increase burner input in a coordinated manner to maintain the steam setpoint.
In addition, the three-pass fire-tube design, pressurized combustion, and the fully water-cooled reversal chamber contribute to stable operation, with good heat transfer and low flue-gas pressure drop. This architecture supports consistent performance whether heat comes from combustion or from the electric input, helping to maintain continuity of steam supply in industrial processes.
When the boiler is configured with automation, this coordinated management minimizes the risk of pressure drops associated with load changes, helping to protect process continuity. The three-pass arrangement and the water-cooled reversal chamber provide operational stability both with electric input (high-temperature resistance elements) and with combustion input. Overall, the HHE Hybrid enables fast transitions between modes or in hybrid operation, reducing the need for manual intervention and helping to maintain a stable steam supply for demanding applications (for example, in the food or chemical industries), depending on the control strategy and plant integration.