Ljungström air preheater is an

air preheater An air preheater is any device designed to heat air before another process (for example, combustion in a boiler), with the primary objective of increasing the thermal efficiency of the process. They may be used alone or to replace a recuperati ...

invented by the Swedish engineer

Fredrik Ljungström Fredrik Ljungström (16 June 1875 – 18 February 1964) was a Swedes, Swedish engineer, Industrial design, technical designer, and industrialist. Considered one of the foremost inventors of Sweden, Fredrik Ljungström accounted for hundreds ...

(1875–1964). The

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

was achieved in 1930. The factory and workshop were in

Lidingö Lidingö (), also known in its definite form Lidingön and as Lidingölandet, is an island in the inner Stockholm archipelago, northeast of Stockholm, Sweden. In 2023, the population of the Lidingö urban area on the island was 48,162. It is the ...

throughout the 1920s, with about 70 employees. In the 1930s, the facilities were used as a film studio, and they were demolished in the 1970s to give space for new development. In 1995, the Ljungström air preheater was distinguished as the 185th International Historic Mechanical Engineering Landmark by the

American Society of Mechanical Engineers The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing edu ...

. Ljungström's technology of the air preheater is implemented in a vast number of modern

power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

s around the world, with total attributed worldwide

fuel savings Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may ...

estimated at 4,960,000,000 tons of

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

, "few inventions have been as successful in saving fuel as the Ljungström Air Preheater". In modern

boilers A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central ...

, the preheater can provide up to 20% of the total

heat transfer Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, ...

in the boiler process, while only representing 2% of the investment.

References

External links

History of the Ljungström Air Preheater

LJUNGSTRÖM Air Preheater (APH) & Gas-gas Heater (GGH) Power Plant Overview
Chemical equipment Mechanical engineering Power station technology Engineering thermodynamics Ljungström {{Powerstation-stub