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Flue Gas Condensation & Heat Recovery

Maximize boiler efficiency by recovering waste heat from flue gases using Thermax absorption heat pumps combined with SEGFlu scrubber technology. Reduce chimney temperatures from 150°C+ down to 15-25°C while capturing condensation energy for district heating networks.

Transform Waste Into Valuable Energy

Flue gas condensation is one of the most effective methods to increase overall boiler plant efficiency. By cooling exhaust gases below their dew point, we recover the latent heat of condensation — energy that would otherwise escape through the chimney.

Thermax absorption heat pumps, deployed in partnership with our Danish distributor SEG Energy and their proprietary SEGFlu flue gas scrubbers, provide a proven solution for this application across Scandinavia and Central Europe.

The system works by circulating cold water from the heat pump’s evaporator through the flue gas scrubber, cooling exhaust gases to near-ambient temperatures. The recovered energy preheats district heating return water, dramatically improving overall plant efficiency.

SEGFlu flue gas scrubber with Thermax absorption heat pump

System Flow & Energy Recovery

A closed-loop system that extracts maximum energy from boiler exhaust while preheating district heating water.

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Boiler Exhaust

Hot flue gases exit boiler at 150-180°C containing significant waste heat

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Flue Gas Scrubber

SEGFlu scrubber cools gases with chilled water from heat pump evaporator

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Condensation

Flue gas cooled to 15-25°C, recovering latent heat of water vapor condensation

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District Heating

Recovered heat preheats return water from 45°C to 70-85°C before boiler

Why Flue Gas Condensation?

+15%

Efficiency Increase

Boost overall plant efficiency by 10-20% by capturing waste heat that would otherwise be lost through the chimney stack.

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Fuel Savings

Significant reduction in fuel consumption as recovered heat reduces boiler firing requirements — rapid payback typically under 5 years.

CO₂

Carbon Reduction

Lower emissions by reducing fuel burn — critical for meeting climate targets and regulatory requirements.

24/7

Continuous Operation

Designed for 8,000+ hours per year operation with minimal maintenance — proven reliability in demanding district heating applications.

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Water Recovery

Condensed water from flue gases can be treated and returned to the boiler feedwater system, reducing makeup water requirements.

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Biomass Compatible

Ideal for wood chip and biomass boilers where high moisture content in exhaust creates significant condensation potential.

Case Studies from Denmark

Thermax heat pumps deployed by SEG Energy across Danish district heating plants demonstrate exceptional performance and reliability.

🇩🇰 Denmark · 2021

Amager Bakke (ARC) Waste-to-Energy Plant

  • 8 × Thermax absorption heat pumps
  • 32 MW total cooling capacity
  • Series configuration (2×4)
  • Copenhagen district heating
Result:

Northern Europe’s largest flue gas condensation installation — one of world’s most innovative waste incineration plants.

🇩🇰 Denmark · 2016

Lemvig District Heating

  • Thermax 5G3MC heat pump
  • 900 kW cooling capacity
  • Wood chip boiler heat source (115°C)
  • Stainless steel evaporator
Result:

Chimney temperature reduced to 18°C, dramatically increasing boiler output and plant efficiency.

🇩🇰 Denmark · 2014

Vestervig District Heating

  • Thermax LT10C heat pump
  • 300 kW cooling capacity
  • Chip boiler application
  • Scrubber water at 12°C
Result:

Flue gas cooled to 12°C, maximizing condensation heat recovery and overall plant efficiency.

🇩🇰 Denmark

Egedal District Heating

  • Thermax absorption heat pump
  • Chip boiler (115°C drive heat)
  • Chimney temp reduced to 25°C
  • Complete SEG turnkey delivery
Result:

Most energy in flue gases recovered, significantly improving plant economics and carbon footprint.

🇸🇪 Sweden · 1997

Uppsala Waste Incineration

  • 4 × SANYO/Thermax heat pumps
  • 4.7 MW cooling capacity each
  • Steam-driven configuration
  • Flue gas condensation
Result:

One of Europe’s earliest large-scale flue gas condensation projects — proven 25+ year track record.

🇸🇪 Sweden · 1986

Eksjö Waste Heating Plant

  • SANYO/Thermax 3.2 MW unit
  • Hot water driven (incinerator)
  • Flue gas condensation
  • Pioneer installation
Result:

Nearly 40 years of continuous operation demonstrates exceptional longevity of absorption technology.

System Parameters

Heat Pump Type
Single-effect steam or hot water driven absorption
Cooling Capacity Range
300 kW to 40 MW (modular configurations)
Heat Source Temperature
110-120°C (from biomass or gas boiler)
Flue Gas Inlet Temperature
150-180°C (before scrubber)
Flue Gas Outlet Temperature
12-25°C (after condensation)
District Heating Return Temp
40-50°C (typical)
District Heating Supply Temp
70-85°C (after heat pump)
Evaporator Metallurgy
Stainless steel (for scrubber water compatibility)
COP (Coefficient of Performance)
1.6-1.7 (based on heat source conditions)
Typical Efficiency Increase
10-20% overall plant efficiency improvement
Applications
Biomass boilers, waste incineration, gas boilers, CHP plants
Operating Hours
8,000+ hours/year continuous duty

Maximize Your Boiler Efficiency

Our engineering team will design a custom flue gas condensation system for your district heating plant or industrial boiler.

Request Feasibility Study
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