Chaudière Haute Performance
High-Temperature Boiler

Context and challenges

Working via its subsidiary company Cofely Services, ENGIE has developed a high-performance, high-temperature boiler. The solution uses a water vapor pump (WVP) which combines mature high-performance condensing boiler technology with a special feature developed by the ENGIE research center subsidiary company, which consists of recovering the lost energy generated in a traditional condensing boiler, and re-injecting it into the incoming combustion air stream.

The solution

At the end of the combustion process, the heat energy contained in boiler flue gases is cooled from 220°C to 80°C in a condenser. This temperature reduction produces energy-rich condensates, which are recovered as unavoidable energy and reused by being re-injected into the boiler combustion air stream.

The second post-boiler heat exchanger completes the cycle by collecting the residual energy contained in the boiler flue gases and stabilizing them at a temperature of 40°C. Two pumps maintain the recirculation cycle between the two heat exchangers; one for cooling, and the other for heating.

This 'Ultra-high-performance 109' system is distinctive for the fact that at 60°C, the air at one end of the combustion-based energy generation system is warmer than the combustion products themselves (40°C) and that between the two, water has been heated to 90°C. Intuitively, it is clear that this system delivers a level of efficiency much higher than is normal for this type of system.

The characteristics of the solution make it best suited for heating systems consuming more than 4GWh per year.


Five installations using this new-generation boiler have been running in the Paris region for the last two years.

The combination of a condensing boiler used in an 'Ultra-high-performance 109' system and the EFFIGAZ program - a Cofely Services package guaranteeing at least 10% lower space heating and hot water energy bills for multi-occupancy buildings over a period of eight years with no upfront investment - can achieve previously unattainable levels of performance.

Key figures

  • Measured efficiency of 109% HCV (Higher Calorific Value), whereas other boilers in the same category struggle to achieve 89%
  • A guaranteed greenhouse gas emissions reduction of 20%, compared to similar technical solutions
  • A 75% reduction in fine particulates, such as nitric oxide

Operation of the High-Efficiency, High-Temperature Boiler developed by Cofely Services

Operation of the High-Efficiency, High-Temperature Boiler developed by Cofely Services