Evaporation-driven engine

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.17 × C.23 · Humidity gradient × Electrokineticfamily: Electrokinetic

Measured or reported performance

1. peak electrical power (bursts)60 mWdevice2015
   the evaporation-driven oscillatory engine (spore-based HYDRA muscles on a buckling beam with a shutter) coupled to a generator, resting on water at 30 °C, the HYDRAs covering 9.6 cm × 7.6 cm of water surface
   refs [1]
2. average electrical power1.8 mWdevice2015
   as above; the authors expect the waiting periods to shrink with more compact designs
   refs [1]

Steps

1. 01
   Humidity gradient —drives→ Evaporationestablishedclaim record

   chemical → chemical · loss to thermal

   liquid · humidity difference required

   refs [1] [2]
2. 02
   Evaporation —produces→ Mechanical motiondemonstratedclaim record

   chemical → mechanical

   • hygroscopic spores or films that swell and shrink with humidity, driving a piston or oscillator

   refs [1]
3. 03
   Mechanical motion —converts into→ Mechanical workestablishedclaim record

   mechanical → mechanical · loss to thermal

   refs [2]

Evidence for the complete composition · 1

1. [1]
   X. Chen et al.. Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators (2015)

   Nature Communications 6, 7346 · doi:10.1038/ncomms8346 · crossref ✓ 2026-09-19 · record

Evidence for the constituent relations · 2

1. [1]
   X. Chen et al.. Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators (2015)

   Nature Communications 6, 7346 · doi:10.1038/ncomms8346 · crossref ✓ 2026-09-19 · record
2. [2]
   A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)

   Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record