The Trompe: A Basic Overview

A trompe is an ancient technology which uses falling water to compress air. The compressed air can then power machinery, aerate water, refrigerate, etc. Although the trompe fell out of fashion once fossil fuels became a major source of energy, the modern world can still harness its power.


A trompe, often placed in a river, has a simple design. Flowing water falls into an intake pipe which has an air cone (or some other aerating device) on top. The water falling around the cone creates suction, pulling the air down with it. Air bubbles travel down the pipe with the water until reaching an air chamber.

At the air chamber (also called a plenum or reservoir), the bubbles escape from the water. In the process, the air has been compressed, dehumidified, and cooled to the same temperature as the water. The pressurized air can now be put to use.

Meanwhile, the water leaves through the outtake pipe. Air pressure from the reservoir pushes the water upwards, nearly to the same height it originally fell from, and the water returns to the river.

Alternate Designs

The trompe can be tailored to fit within various restrains. For instants, Geoff Lawton describes a compacted version of the trompe, where the intake pipe is held withing the outtake pipe.

The air-intake can also be modified. For example, an aspirator pump–basic equipment found in chemistry labs–also uses the Venturi effect to create suction. In the processes, it introduces air into the systems.

The aspirator looks like the inverse of a trompe, with the air entering around the constricting water pipe, as shown below:

CC BY 3.0; Peter Forster

Combining the trompe with other devices can improve the trompe’s efficiency. Mr. Teslonian combined a trompe with a water hammer and one-way valves to greatly increased the generated air pressure.



Historically, miners created large-scale trompes to power their mining equipment and provided ventilation. A 350-feet-deep trompe in Michigan was recorded to produce 5,000 horsepower. A similar mine in Canada (Ragged Chutes, the world’s largest trompe) still operates today.

Though there hasn’t been much scientific testing, a small-scale trompe could prove just as useful. Applications range from single-home air conditioning to community-wide electrical production.

Trompes can use compressed air for:

  • powering machinery (pnuematic drills, sandblasters, etc.)
  • direct refrigeration
  • pollutant-free cars
  • elevators and lifts
  • generating electricity
  • Catalan forges
  • air for a scuba-diving breathing apparatus

Trompes’ electricity-free water aeration can:

  • revive anaerobic rivers
  • treat sewage
  • control algae
  • increase aquaculture yield
  • aid in chemical mixing

Other possible uses include:

  • ventilation in mines
  • powering fountains and moving water uphill (pulser pipes)
  • laundry washing machines (as mentioned by Brian White)
  • harnessing energy from tidal waves and rivers

Further Research

At Lost Technology, we would like to design and collect data from small-scale trompes. We believe that trompes, if researched and developed, can help individual households and large corporations alike. Plans for further research are being developed. If you wish to help in any way, please contact us here.


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