Use case 2 summary: Gas-water heaters
The Sure2Coat use case 2 has used laser treatment to increase the heat transfer in gas-water heaters and surface treatment to reduce corrosion of the copper surface in the equipment.
The EU funded project Sure2Coat was granted with the objective of developing novel surface treatment methods suitable for complex shapes and develop approaches for integration into manufacturing lines. Three different applications, called use cases, were used to demonstrate three different surface treatments; Gas-water heaters, accessory gear box housing, and heat transfer enhancers for salt-hydrate based heat storage units.
The aim of the Sure2Coat use case 2 was to use laser treatment to increase the heat transfer in the GWHs and so be able to reduce the number of fins (5% less copper use per unit) without affecting the equipment performance. The other goal was to use the surface treatment (ST) to reduce the wettability of the Cu surface and so reduce the corrosion that affects the lifetime of the equipment.
Environmental and Industrial Impact of Laser Surface Treatment
Sure2Coat potential impact of improved GWHs is to reduce both the material (copper) consumption, energy for processing and climate and pollution goals, set for 2050 through the Fit for 55 EU ambition. Applying laser-based surface treatment instead of chemicals based, will reduce the use, and potential release of harmful components to nature. Thus, a production line with laser-based surface modifications has many potential benefits.
The laser treatment had a positive impact on the aging of the combustion chamber and on the reduction of the corrosion products formed on the copper surface of the heat exchanger fins block. Sure2Coat have showed that the ST can reduce the corrosion, and the accumulation of combustion products which is expected to improve the assurance of product specifications throughout the lifetime of the equipment. By improving the operational conditions of the equipment during lifetime expected, it’s expected that periodic maintenance interventions can be reduced and product performance can be kept during entire lifetime. While laser surface treatments have previously been used to reduce copper wettability, this is the first time the technique has been applied to gas-water heaters.
Industrial Validation and Research Collaboration
Bosch Termotecnologia, SA has been the main industrial partner in the use case, responsible for performing the validation and uptake of the developed technology. Universidade de Aveiro has been responsible for the research work concerning laser surface treatments.
The innovations align with Bosch's business strategy and goals in the Heating, Ventilation, and Air Conditioning (HVAC) industry by contributing to enhanced energy efficiency, cost-effectiveness, technological leadership, market differentiation, sustainability, and customer value proposition.
The technology can contribute to position Bosch as a leader in providing innovative and efficient HVAC solutions, supporting the company's aspirations to become a prominent player in the industry.
Benefiting Multiple Heat‑Exchanger Markets
In a wider context, the innovations are likely to benefit several market segments, particularly those with a strong emphasis on energy efficiency, cost-effectiveness, and durability in heat exchangers and related applications.
The following market segments are most likely to benefit from the innovations:
- Residential HVAC Systems: Meeting the demand for more energy-efficient solutions, reduced operating costs and product reliability.
- Commercial and Institutional Buildings: Many office buildings, educational institutions, healthcare facilities, and hospitality establishments, have a strong focus on energy efficiency and operational cost savings and demands reduced maintenance costs, and enhanced system reliability.
- Industrial HVAC and Refrigeration: Manufacturing facilities, food processing plants, and cold storage warehouses, have a high demand for durable and efficient heat exchangers. Lase treatment may be used in developing and optimizing heat transfer units for industrial HVAC and refrigeration applications.
- Automotive and Transportation: The need for compact, durable, and energy-efficient heat exchangers in automotive applications aligns with the potential advantages offered by the innovations, including space-saving designs, enhanced durability, and improved thermal performance.
- Renewable Energy Systems: The innovations' potential to improve heat transfer efficiency and reduce maintenance requirements align with the needs of renewable energy applications, where maximizing energy capture and minimizing operational costs are critical.
Future Work and Implementation
The laser technology is remarkable for being easy to implement in production lines, despite that there are still implementation challenges. Adding the surface laser treatment to the current manufacturing line without compromising the energy efficiency can be viable by choosing laser equipment’s with an energy efficiency higher than the ones used in the research phase; even so, the difficult balance is to keep a balance to avoid product cost increase to the customer.
Having the laser technology implementation cost better adjusted, crucially, further comprehensive testing is required to conclusively prove that reducing the number of fins can be achieved without compromising the long-term durability and performance of the appliance.
If we want to keep the current production rate, we need to study some alternative in which the laser is used together with other approaches. But the developed ST maybe viable for other BOSCH products that do not demand the same production rate.
Beyond copper, the potential of this laser treatment should also be explored for other materials commonly used in heat exchangers, such as stainless steel, aluminium, and zinc plate, particularly for products with a higher cost or value-added where the benefits of advanced surface treatment would be more impactful for the manufacturer.
References
A.M.P. Botas, A.F. Carvalho, A.J.S. Fernandes, B.P. Falcão, K. Yasakau, J.P. Leitão, J. Tedim, F.M. Costa, Laser Patterning for Fast Production of Superhydrophobic Copper with Delayed Formation of Patina and Maintenance of Surface Electrical Conductivity, Appl. Surf. Sci., 686 (2025) 162108. https://doi.org/10.1016/j.apsusc.2024.162108.
A.M.P. Botas, A.F. Carvalho, K. Yasakau, N.M. Ferreira, G. Miranda, J. Tedim, F.M. Costa, Laser Patterning for the Modification of Copper’s Wettability: A Systematic Review, Appl. Surf. Sci. Adv., 30 (2025) 100882. https://doi.org/10.1016/j.apsadv.2025.100882.
M. La, T.Y. Hwang, J.-Y. Choi, S. Hong, S.J. Park, J. Kang, D. Choi, Development of a Metal-to-Metal Imprinting Process: Transcription Quality Analysis and Surface Wettability Characterization, Appl. Surf. Sci., 527 (2020) 146823. https://doi.org/10.1016/j.apsusc.2020.146823.
Contact
For more information, please contact Martin Fossen, Senior Research Scientist, SINTEF: