Comprehensive engineering calculations were performed for the industrial (floor-standing) NKE series heating boilers manufactured by Tenko. The study determined the optimal heat exchanger geometry and proposed the recommended specifications for selecting the appropriate circulation pump.
To streamline the mathematical model while maintaining an acceptable margin of error, a set of valid engineering assumptions was applied to the thermal and fluid dynamics calculations.
The system calculations primarily focused on the following:
- Determining the minimum heat transfer fluid flow rate required to strictly prevent localized boiling inside the heat exchanger. Among other worst-case scenarios, the calculation assumed that the fluid enters the heat exchanger already at the maximum temperature permitted by the boiler’s thermostat (a critical condition for small-volume systems or systems with poor heat dissipation);
- Based on the constraints from step 1, selecting an optimal flow velocity within the industry-recommended range. Dropping below this target velocity accelerates scaling (fouling) inside the heat exchanger and on the tubular heating elements, while exceeding it causes premature erosion and mechanical degradation of the internal surfaces;
- Calculating and selecting the optimal diameters for the inlet and outlet pipes using standard commercially available pipe sizes, ensuring the fluid velocity remains within the optimal safety range (as defined in step 2);
- Specifying the exact performance requirements needed to select a commercially available circulation pump that meets these fluid dynamics criteria.
Production Rollout and Practical Application
The NKE series boilers have been continuously mass-produced since mid-2016 utilizing these exact proposed parameters. They have demonstrated long-term real-world reliability and efficiency without requiring any subsequent design modifications.