Why extended/finned surface economisers are best

Since Edward Green first patented the economiser back in 1845, many more economisers, sometimes known as flue gas coolers and other What itypes of heat exchanger have been fitted on applications around the world with outstanding results.

What is an economiser?

• Economiser = a product to recover heat from flue gas streams efficiently. Typically used in coal, gas, biomass and waste plants enabling the heat that would otherwise be wasted to be used for secondary applications such as preheating water for further steam generation. This increases plant efficiency, reduces emissions from flues and provides “free” extra energy thereby reducing costs.

Our extended surface economisers, with fins attached, recover more heat and output more energy from its more compact construction.

How it works

• Tubes, finned tubes or modular units containing tubes are fitted in the flue/boiler outlet.
• The hot flue gas heats water in the tubes.
• This heated water makes steam which is used to run a steam turbine or provide a source of heat for industrial processes.


An economiser is easily installed into new or existing applications and can utilize any waste heat source – both high and low temperature and various outputs/flowrates. Green’s products focus on medium and larger scale applications – our current focus is on industrial and power station sized units with fuels such as biomass, waste (waste to energy), coal and gas. There are many forms of biomass from woodchips and straw to sugar cane. Our economisers and flue gas coolers are fitted to paper mills, steel works, sugar mills, petrochemical works, marine vessels – in fact any application with useful waste heat source.

Economiser tube types

• H Fin, extended surface (single or double fin) – using our proprietary Green’s finning machines. Used in all fuel applications (biomass and waste to energy applications and of course coal). H fin economisers optimise space for ash/dusts to pass through economiser – low fouling – as well as output from fin formation

• Cast Iron configuration – often used for dirtier carbon fuels and lower temperatures/corrosive environment.

• Spiral Fin – most often used on gas/cleaner applications where spiral fin surface with a closer fin pitch.

Why Green’s?

• Green’s remains the originators, the largest and the most referenced (most projects) supplier of economisers in the world, working either with the end user, the world’s largest boilermakers, or EPC contractors.

• We design economisers using our proven design program which can quickly assimilate from past inputs and outputs to give customers the optimised products for their application.

• We supply complete units or coil applications ranging from tube bundles to full equipment packages.

• We use best quality materials, fully certified, traceable and compliant – operating under ISO, EN and ASME codes.

• We supply worldwide (from Yorkshire to Australia currently) using our own facilities and developed machines from the UK and also partner facilities in Asia – all of which use the strong quality and service ethos from Green’s 180 year history.