Hybrid Furnace
What is a hybrid furnace?
A hybrid furnace is a specialized glass melting tank that combines different heating systems within a holistic furnace concept. In industrial practice, this primarily involves the synergistic combination of classic gas heating with modern electric heating elements.
The strategic goal of this approach is to specifically leverage the unique advantages of both energy sources. This allows the melting process to be highly flexible and adaptable to technical requirements, fluctuating energy prices, and increasingly stringent regulatory frameworks.
Unlike purely gas-fired glass tanks, hybrid technology allows for additional electrical energy input, which primarily serves to stabilize and precisely fine-tune the temperature profile. Compared to all-electric systems, it offers the crucial advantage that the existing gas-based infrastructure can continue to be used. This makes the hybrid furnace an ideal bridging technology for a gradual and economically secure transition to low-CO₂ melting processes.
Hybrid furnace from the inside
// IWG Glasofenbau
Gas and Electrically Heated Hybrid Furnaces
In this classic hybrid concept, gas firing continues to provide a significant portion of the thermal energy. The integrated electric heating elements are used specifically to optimize glass quality through precise temperature control in the molten glass bath.
This configuration allows for flexible load distribution: depending on the availability or price development of energy sources, the electrical share can be successively adjusted. This is a particularly attractive way to reduce CO₂ emissions for modernization projects (full repairs) without having to fundamentally abandon the proven plant layout.
Furthermore, the targeted placement of the electrodes enables precise control of the glass bath convection, which significantly improves the homogenization of the melt. This thermal stability minimizes the wear of the refractory material on the bottom and side walls, which can extend the campaign life of the furnace.
Technical Glass
C-glass, E-glass, borosilicate glass, neutral glass, sodium silicate glass, display glass, and glass-ceramic
Tableware
Crystal glass, borosilicate glass, soda-lime glass, crystal glass
Glass Containers
Soda-lime glass, borosilicate glass
Glass Conditioning
Forehearths for various glass types
Glass Conditioning
Platinum Feeder System
Oxy-Fuel and Electrically Heated Hybrid Furnaces
This technologically advanced variant combines oxygen-assisted combustion with additional electric heating. By using pure oxygen instead of ambient air, the nitrogen ballast is eliminated, leading to significantly higher flame temperatures and a reduced exhaust gas volume.
The supplementary electric heating ensures a homogeneous heat distribution deep within the glass bath. This concept is characterized by maximum energy efficiency and is preferably used where the highest glass quality is to be produced in a limited space.
Furthermore, the elimination of nitrogen massively reduces the formation of thermal nitrogen oxides (NOx), which often allows for smaller-sized, complex exhaust gas purification systems. The combination of both systems also allows for an exceptionally compact design of the melting tank, as the specific melting capacity per square meter of surface area increases drastically due to the concentrated energy input.
Technical Glass
C-glass, E-glass, borosilicate glass, neutral glass, sodium silicate glass, display glass, and glass-ceramic
Tableware
Crystal glass, borosilicate glass, soda-lime glass, crystal glass
Glass Containers
Soda-lime glass, borosilicate glass
Glass Conditioning
Forehearths for various glass types
Glass Conditioning
Platinum Feeder System
Can hybrid furnaces be customized?
A key advantage of hybrid furnaces is their high compatibility with existing plant components. They can be designed in such a way that proven systems such as bubbling systems, exhaust systems, feeders, as well as cooling and control equipment can either be directly reused or adapted with minimal effort.
Especially in modernization projects (brownfield projects), we at IWG Glasofenbau place great emphasis on precisely tailoring the hybrid furnace's design and control technology to the existing infrastructure. This not only minimizes the necessary interventions in the building structure but also significantly reduces initial investment costs.
Furthermore, this concept allows for a gradual electrification of the melting process. Instead of having to convert the entire operation in a single, risky large-scale project, existing systems can be successively expanded or supplemented with additional electrical components. This modular approach ensures that investments remain plannable over several campaigns and the transformation process towards low-CO₂ production can proceed without lengthy operational interruptions. IWG Glasofenbau integrates these strategic aspects deep into the planning phase to guarantee technical compatibility and long-term operational reliability throughout the entire lifecycle of the plant.
Conditioning
Plunger, screw, and individually adapted batch charger solutions
Equipment
Fuel heating technology
Equipment
E-Boosting
Equipment
Air cooling
Equipment
Furnace pressure measurement
Equipment
Bubbling
Equipment
Glass level measurement
Equipment
Control and measurement technology
Equipment
Drainage system
The fundamental difference: Electric boosting vs. hybrid furnace
It is important to distinguish between a simple boosting system and a true hybrid furnace. Electric boosting merely acts as a supporting auxiliary technology for an existing gas-fired furnace. It serves to compensate for specific temperature deficits or to temporarily increase melting performance, while the primary dependence on gas remains.
The hybrid furnace, on the other hand, is designed from the ground up as an integral system. Here, gas and electricity are equal partners in terms of design and control technology. The electric heating is firmly integrated into the process management and is designed to play a crucial role throughout the entire lifecycle of the plant.
The differences in direct comparison:
- Strategic role: While boosting selectively optimizes an existing plant, the hybrid furnace serves as the basis for a complete transformation of melting technology.
- Energy share: With boosting, the electricity share usually remains low (supplementary heating); in a hybrid furnace, both energy sources are equivalent and flexibly controllable.
- Plant design: Hybrid furnaces are designed for high electrical loads (e.g., special electrode arrangement and bottom cooling), which is often only possible to a limited extent in standard gas-fired furnaces with boosting.
- Future-proofing: The hybrid furnace allows for a successive increase in the electricity share over several campaigns, whereas boosting reaches its technological limits as soon as gas is no longer intended to be the main energy source.
Thus, while electric boosting is a reactive measure for increasing efficiency, the hybrid furnace acts as a proactive foundation for companies wanting to secure their production capacities independently of fossil fuel markets.
Advantages and limitations of hybrid melting technology
The use of hybrid furnaces offers significant advantages in modern process management. A key aspect is economic resilience: The high flexibility in the choice of energy sources allows operators to react dynamically to price fluctuations in the gas and electricity markets, thus actively optimizing their operating costs. From a technological perspective, precise electrical control leads to significantly more stable melt homogeneity, which minimizes the rejection rate and increases product quality, especially for demanding types of glass. Furthermore, the hybrid concept enables a long-term, risk-minimized decarbonization strategy: Since the electrical share can be increased over several campaigns, investments remain scalable and are aligned with the actual progress of local infrastructure development.
Your advantages at a glance:
- Cost-efficiency: Dynamic response to fluctuating energy prices (gas/electricity).
- Quality assurance: Higher homogeneity through precise electrical temperature control.
- Plannability: Scalable investments through gradual electrification.
The combination of heating media also reduces the thermal inertia of the furnace, enabling faster adjustments during product changes or throughput modifications.
Technical limitations and infrastructural requirements
At the same time, however, the technical and operational limits must also be considered transparently. The system complexity of a hybrid furnace is significantly higher compared to conventional, purely gas-fired furnaces. This places increased demands on the control and regulation technology as well as on the operating personnel, who must be trained to handle high-performance electrical heating components. Another critical factor is the site-specific economic viability:
The advantages of a hybrid furnace can only be fully exploited where a sufficiently dimensioned grid connection is available or can be implemented in a timely manner. In addition, the integration of different heating systems requires precise coordination of the refractory materials, as the altered thermal load and flow dynamics in the glass bath must be taken into account when selecting materials. Hybrid furnaces are therefore not a universal "plug-and-play" replacement, but a highly specialized solution whose success is closely linked to a well-founded site analysis and a clear long-term transformation strategy.
Factors to consider:
- Complexity: Higher demands on sensor technology, control systems, and personnel expertise.
- Infrastructure: Necessity of a high-performance electrical grid connection on-site.
- Material stress: Special requirements for refractory materials due to altered glass bath convection.
Additionally, due to the high voltages in the melting area, the electrical safety technology (e.g., grounding concepts and insulation monitoring) must be designed much more elaborately than for standard furnaces.
Super-hybrid furnaces as a further development of hybrid melting concepts
Super-hybrid furnaces represent the logical evolution of classic hybrid concepts and are optimized for a massively increased share of electrical heating. While in standard hybrid furnaces the fossil and electrical energy input are often still in a balanced ratio, the focus in super-hybrid systems shifts drastically in favor of electricity.
The basic technological principle is to maintain the operational flexibility of hybrid heating while reducing dependence on fossil fuels to a minimum. In this scenario, electric heating takes over the main share of the melting power, while gaseous energy sources are only used supplementarily for specific process phases or for top-heat support. A crucial future advantage: The remaining gas infrastructure can be converted to CO₂-free gases such as hydrogen or biogenic methane in the future without any system disruption.
Strategic relevance for modern production sites
The super-hybrid furnace is the ideal solution for sites pursuing the following goals:
- Maximum emission reduction: Significant reduction of energy-related CO₂ levels while maintaining process stability.
- Infrastructural bridge: Perfectly suited for plants where 100% electrification is not (yet) technically or grid-side feasible.
- Investment security: The concept offers maximum degrees of freedom for the long-term plant strategy, as it can be modularly adapted to the availability of green energy over several campaigns.
By being designed as a 'high-electric' system, the super-hybrid furnace forms a resilient technological bridge between today's melting processes and the all-electric glass furnaces of the future.
IWG Glasofenbau already considers these evolutionary stages in the initial planning phase. We develop plants that not only meet today's requirements but are also prepared for the energy framework conditions of the coming decades.
Modernization of existing hybrid systems
Existing hybrid plants offer an excellent basis for technological upgrades. Since the basic infrastructure for various energy sources is already in place, modernizations can be implemented in a targeted manner without having to interfere with the core structure of the glass furnace. The focus here is primarily on increasing the performance of the electrical components and implementing state-of-the-art control and regulation technology.
The advantages of targeted modernization by IWG Glasofenbau:
- Future-proof adaptation: Increasing the degree of electrification and connecting to modern energy infrastructures to meet new regulatory CO₂ requirements.
- Maximum resource efficiency: Existing exhaust, feeder, and bubbling systems (plumbing) can often be retained or optimized with little effort.
- Minimized downtime: Through modular planning, measures can be implemented campaign by campaign, reducing downtimes to an absolute minimum.
- Plannable investments (CAPEX): Instead of a risky complete new build, we enable a step-by-step modernization that is perfectly aligned with the long-term strategy of your site.
Hybrid furnace from IWG Glasofenbau
The realization of efficient hybrid and super-hybrid furnaces requires in-depth expertise in melting technology and a precise understanding of modern plant structures. IWG Glasofenbau provides comprehensive support – from the initial technical analysis and conceptual planning to the final implementation during ongoing operations.
We consider heating concepts, energy infrastructure, and control technology as an inseparable unit to guarantee maximum process reliability with optimal economic efficiency. Whether for a complete new build or the step-by-step modernization of your existing plants: Our solutions are consistently designed to make your production site technologically flexible and fit for global decarbonization in the long term.