FLU-ACE™
Turning Stack Losses into Long-Term Value
FLU-ACE is a direct contact condensing heat recovery system for industrial flue gas applications that captures energy normally lost with boiler or process flue gases and recycles it as usable hot water. By cooling the exhaust and condensing the water vapour, FLU-ACE recovers up to 90% of stack heat losses, delivering typical fuel savings of 15–20% with proportional reductions in emissions.
Benefits
Recover More Energy, Save More Fuel
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Recover up to 90% of stack losses.
At a prominent Food & Beverage facility, two FLU-ACE heat recovery towers (one on the boiler system and one on process dryer exhausts) cut fuel use by 15% and eliminated more than 7,300 tonnes of CO₂ per year. A global pharmaceutical plant in the USA recovered heat from four boiler exhausts and vent streams, delivering annual savings of $740,000 and avoiding 1,280 tonnes of CO₂.
Cut fuel use by 15–20% with payback in 2–5 years.
Payback is typically achieved in two to five years, with performance lasting for decades. A US Food & Beverage facility cut gas use by 10% and saved £322,000 per year with a simple payback in under two years. At a prominent hospital in Canada, FLU-ACE has been operating for more than 30 years, still saving $250,000 annually and cutting 1,500 tonnes of CO₂ emissions each year.
Engineered in stainless steel for 20+ years of service.
All wetted surfaces are stainless steel, engineered to resist acidic condensate and provide decades of service. Its internal design ensures an unobstructed flow of gas and liquid, enabling virtually continuous operation with limited downtime. Units have been running for more than 30 years with minimal maintenance. Even in challenging, dirty Pulp & Paper and tissue machine exhaust heat recovery applications, FLU-ACE heat recovery has proven decades of reliable, low maintenance performance.
Reduce CO₂ and capture up to 90% of water vapour for reuse.
FLU-ACE condenses up to 90% of flue gas vapour, reducing visible plumes and providing water for potential reuse. At a major tissue producer, annual CO₂ emissions fell by 8,853 tonnes, while at a UK hospital CO₂ emissions were cut by 704 tonnes and more than 98% of sulphur dioxide was removed alongside a 20% reduction in gas use.
Integrate seamlessly with existing boiler and process exhausts with no downtime.
Installed in parallel with the existing stack, FLU-ACE ensures uninterrupted boiler and process operation. If the unit is offline, flue gases vent as they did prior to FLU-ACE installation. At a UK hospital, two units were installed without disrupting service, cutting 1,000 tonnes of CO₂ annually. At a major infant formula facility, FLU-ACE was integrated into 24/7 production, reducing natural gas consumption, cutting more than 7% of site-wide energy use, and supporting the customer’s decarbonisation program without impacting reliability.
HOW IT WORKS
From Flue Gas to Fuel Savings
Boiler flue gases are directed into the FLU-ACE tower, where they contact a descending water stream across stainless steel packing. As the gases cool, both sensible heat and latent heat released during vapour condensation are absorbed into the water.
The heated water is collected in a receiver for distribution to building or process loads or transferred via a secondary heat exchanger where separation is required. Condensation within the tower also removes most of the water vapour from the exhaust, reducing plume volume and providing recoverable water.
Installed in parallel with the stack, FLU-ACE ensures uninterrupted boiler operation. Variable-speed induced draft fans maintain stable pressure, and analysis confirms the system’s ability to recover the maximum available energy from boiler exhaust.
Product Specs
Performance That Lasts
Following decades of operation across industrial and institutional sites, FLU-ACE has a documented record of reliable performance, with many installations still delivering verified savings up to 30 years after commissioning.
Fuel savings:
10 to 20% (typical range, depending on load and application)
Heat recovery:
Up to 90% of stack losses
Hot water output:
Up to 63 °C as standard; up to 82 °C with alternate design
Water recovery:
Up to 90% of water vapour in the flue gas condensed
Integration:
One unit can process exhaust from multiple boilers or process sources
Construction:
Stainless steel internals
CASE STUDIES
FLU-ACE in Operation
Installations worldwide continue to deliver measurable reductions in fuel use and emissions, with long-term results demonstrated in the following case studies.
Frequently Asked Questions
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Typical installations reduce fuel use by 15 to 20% with a two-to-five-year payback, then continue to save for more than 30 years. Additional financial benefits can sometimes be realised through local carbon reduction schemes enhancing project savings.
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Conventional designs mainly capture sensible heat. The FLU-ACE heat recovery unit captures both sensible and latent heat, which is why it can deliver 200 to 300% more usable energy and approach 9% stack heat recovery.
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Yes. A single tower can handle varying flows from multiple boilers and process stacks, lowering capital cost and simplifying operation. One unit can even serve multiple sources such as CHP, boilers and a variety of processes.
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Recovered heat from FLU-ACE can be applied to a wide range of uses, including domestic hot water, hydronic and space heating, boiler makeup water preheating, process water heating, combustion air and makeup air preheating, and even low temperature drying lines or biomass drying integration.
Additionally, heat recovered with a FLU-ACE can be increased in temperature for broader application with a heat pump, generating far superior coefficients of performance (COPs) than air or ground source heat pumps. In fact, latent heat can be recovered and upgraded to steam in our “FreeSteamingTM” combined heat recovery or mechanical vapour recompression applications, closing the latent heat cycle on dryers and other processes.
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No. The FLU-ACE heat recovery system is designed as a failsafe parallel installation. If the unit is offline, flue gases flow through the existing stack as they did before. During FLU-ACE operation, variable speed induced draft fans control gas flow without creating back pressure, so boiler and process operation remain unaffected.
Sustainability that pays for itself.
Solutions that deliver verified returns from day one.
Speak to our team
If you are exploring how to cut energy use, reduce emissions or assess the viability of steam, heat recovery or hot water solutions for your site, our team can help you understand what is possible.
- Identify where energy is being lost
- Understand the most effective efficiency improvements for your site
- Gain clear guidance on performance expectations and practical implementation