How NIR-b Thermal Imaging Improves Hybrid Furnace Performance

As the steel, metals and glass industries accelerate towards decarbonisation, the hybrid furnace is emerging as a critical technology. 

By combining traditional fossil fuel firing with electrical or hydrogen-based heating, it helps cut CO₂ emissions without compromising process performance.

However, hybridisation also brings new challenges: fluctuating temperature zones, uneven heat distribution, and increased demands for repeatable and accurate control.

That’s where advanced thermal imaging – particularly MWIR-b and NIR-b technology – is making a real difference to operations.

Hybrid furnaces, whether used in reheat, forging, heat-treatment applications or glass production, are designed to integrate multiple energy sources. In most cases, this means combining natural oxy-gas burners with electric boosting or preparing for hydrogen-ready combustion.

While this flexibility improves sustainability and reduces fuel dependency, it also introduces more complex heat patterns. Unlike traditional furnaces with stable flame characteristics, hybrid systems can exhibit:

• Variable emissivity due to changing combustion
• Localised cold or hot spots depending on energy balance (thermal profiles)
• Faster transients during power changes or burner switching (flame characterisation)
• These dynamics make traditional pyrometry (such as the SPOT+, FG or thermocouples) insufficient to guarantee accurate process control and energy efficiency.

Internal view showing heat transfer captured by NIR-b in an oxy-gas furnace. Orange palette used. The furnace is unbalanced, with more energy concentrated on the right-hand side.


The NIR-b Advantage

NIR-b thermal imaging cameras operate in the near-infrared wavelength band (typically around 1 µm), ideal for high-temperature industrial processes. 

Unlike long-wave infrared systems, the NIR-b can “see through” oxy-gas furnace flames and capture clear, radiometrically accurate thermal images of the furnace’s internal surface temperature, even under intense burner radiation, which is common in hybrid furnace technology.

Key benefits for hybrid furnaces include:

• True temperature mapping: Continuous 2D thermal images of slabs, billets or loads across the entire furnace for steel applications; thermal profiles for glass furnaces, enabling easier balancing.
  
  
• Flame-transparent operation with heat transfer insights: Reliable measurement even with fluctuating fuel mixtures (natural gas, hydrogen or syngas).
  
  
• Process optimisation: Early detection of uneven heating or cold zones allows for burner angle adjustments or power tuning.
  
  
• Energy efficiency: More consistent temperature control reduces over-firing and lowers energy consumption.
  
  
• Predictive maintenance: Thermal trends reveal incorrect burner settings, insulation issues or refractory degradation before failures occur.

NIR-b LPAR system in operation on a glass melt tank.


From Visual Observation to Process Optimisation

When integrated into the furnace control system, MWIR-b or NIR-b cameras can act as a real-time feedback source for advanced control algorithms, digital SCADA systems or enhanced MPC/predictive control.

In hybrid furnaces, this integration supports:

• Adaptive control logic that adjusts gas and electric inputs for uniform heating
• Data-driven optimisation, using thermal maps to improve throughput and quality
• Hydrogen transition readiness, as NIR-b performance remains unaffected by changing flame properties

ImagePro V2 Glass interface displaying grid and batch line locations. Five isotherms are applied to the main image to identify the hottest areas.


Supporting the Path to Low-Carbon Production

Hybrid furnaces are a bridge to a greener metals and glass industry, helping producers reduce emissions while maintaining productivity and product integrity.  

Oxy-gas melter visualised using isotherms to show thermal ROI distribution and hottest zones. Flame impact is clearly visible.


By offering accurate thermal imaging in transparent flame conditions, NIR-b technology provides the visibility and control needed to make this transition successful, avoiding damage or critical temperatures.

In the journey to decarbonise high-temperature processes, seeing the process clearly, in the infrared wavelength, has never been more important.

We now have more than 200 NIR-b systems installed globally, supporting the glass industry in improving daily operations, achieving energy savings and extending furnace lifespan.