Xem Studiomeasured geometry

Library › Stirling engines › Guide ·

NASA and Sunpower free-piston Stirling references (public domain) and design numbers

Where are the NASA free-piston Stirling engine design reports and what are the key numbers? · Hardware · basis: NASA Technical Reports Server (NTRS): US Government works are public domain. Headline numbers from the published convertor papers (ASRG, GPHS-ESP, TDC, RE-1000, Sunpower EE-35 / Microgen); hobby-scale rules from Urieli / Berchowitz

Long Earth Society build part. The reading list behind the LES free-piston test bed. The engines · all LES parts

sizes
5 in table

Notes

  • Where the real designs are: NTRS (ntrs.nasa.gov) hosts decades of free-piston Stirling work: the Sunpower RE-1000 test engine (1 kW, 1980s, the best-documented FPSE: dimensions, pressures, strokes, phase angles all published), the Stirling Technology Co. 55 W TDC, the Sunpower ASC/ASRG convertors (80 We class, 102 Hz, helium at 3.5 MPa, 850 °C hot end, flexure suspended, 14+ years on test), Glenn's flexure fatigue and life-test reports, and the thermoacoustic (TASHE) work. Search NTRS for 'free-piston Stirling', 'ASRG', 'RE-1000', 'flexure bearing', 'linear alternator'.
  • Representative numbers: RE-1000: 57 mm bore, 1 kW, 30 Hz, 7 MPa helium, displacer on a gas spring, piston on a gas spring + dashpot load. ASC-E2: ~80 We, 102 Hz, 3.5 MPa He, piston stroke ~5 mm, hot end 850 °C, cold 90 °C, 38% convertor efficiency, flexure-suspended displacer and piston. GPHS-ESP / SRG110: 55 We, 80 Hz. Microgen (Sunpower-derived) domestic CHP: 1 kWe, 50 Hz, helium.
  • Why it matters at hobby scale: the same physics scales down (resonance, clearance seals, flexures, linear alternator), only the pressure and frequency drop: air at 1 bar, 10–20 Hz, 0.1–2 W. The parts on this shelf (flexures, alternator kit, free-piston core, regenerator media, tri-clamp vessel) are the hobby-scale translation of the ASRG parts list.
  • Open design tools: Urieli's Stirling cycle machine analysis (ideal adiabatic + simple models, free online); Sage (commercial, used by NASA); Berchowitz & Urieli 'Stirling Cycle Engine Analysis' (1984) is the standard text; Walker 'Stirling Engines' (1980); Senft 'An Introduction to Low Temperature Differential Stirling Engines' for the can-engine end.
  • Nothing here is NASA's CAD (none is public); the dimensions quoted are from the papers.

Sizes

machinepowerfreq_hzpressurehot_csuspensionntrs_search
Sunpower RE-10001 kW307 MPa He600gas springsRE-1000 free-piston
STC 55 W TDC55 We802.5 MPa He650flexuresTechnology Demonstration Convertor
Sunpower ASC-E2 (ASRG)80 We1023.5 MPa He850flexuresAdvanced Stirling Convertor
Microgen (Sunpower)1 kWe50He500flexuresMicrogen Stirling
LES hobby free-piston0.1–2 W10–201 bar air150printed/steel flexures—

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

NASA (NTRS, public domain)Advanced Stirling Convertor (ASC) development (2010)PDFUS Government work, public domain
NASA (NTRS, public domain)RE-1000 free-piston Stirling engine sensitivity test results (1986)PDFUS Government work, public domain
NASA (NTRS, public domain)Stirling convertor flexure fatigue testing (2008)PDFUS Government work, public domain
NASA (NTRS, public domain)Thermoacoustic Stirling heat engine (TASHE) for space power (2004)PDFUS Government work, public domain
WikipediaAdvanced Stirling radioisotope generatorwebCC BY-SA 4.0 (text)
WikipediaStirling radioisotope generatorwebCC BY-SA 4.0 (text)
Long Earth SocietyEngine buildsweb, videoLES site

Xem scan

Not needed Published standard; the sheet is the geometry.

Plain text: sheet.txt · JSON: /api/geometry?object=nasa-fpse-references

Schematic, not to scale.

Fits with

Free-piston Stirling core: displacer, power piston, liner, gas spring, stops, clearance-seal and tuning tables, isometric render of a generated part
Free-piston Stirling core: displacer, power piston, liner, gas spring, stops, clearance-seal and tuning tables3 sizes★ 11 files
Planar spiral flexure bearings (Sunpower / NASA free-piston style): Ø40–120, DXF + STEP, isometric render of a generated part
Planar spiral flexure bearings (Sunpower / NASA free-piston style): Ø40–120, DXF + STEP5 sizes★ 30 files
Moving-magnet linear alternator kit (free-piston Stirling power take-off), isometric render of a generated part
Moving-magnet linear alternator kit (free-piston Stirling power take-off)6 sizes★ 7 files
Regenerator and heat materials: stainless mesh counts, steel wool, scrubbers, mica, fiberglass, ceramic, firebrick, isometric render of a generated part
Regenerator and heat materials: stainless mesh counts, steel wool, scrubbers, mica, fiberglass, ceramic, firebrick9 sizes★ 5 files
Tri-clamp spool (two ferrules on a tube), 1.5 and 2 inch, isometric render of a generated part
Tri-clamp spool (two ferrules on a tube), 1.5 and 2 inch7 sizes★ 7 files

Questions

Are NASA's Stirling engine designs public?

The reports are (US Government work, public domain, on NTRS): dimensions, operating points, test data and analysis for RE-1000, TDC, ASC/ASRG. The CAD and the Sunpower-proprietary details are not.

What frequency and pressure do NASA Stirling convertors run at?

ASC/ASRG: about 102 Hz on helium at 3.5 MPa with an 850 °C hot end; RE-1000: 30 Hz at 7 MPa; the 55 W TDC: 80 Hz at 2.5 MPa.

Can I build a free-piston Stirling engine at home?

Yes at air pressure and 10–20 Hz: the physics is the same, the output is 0.1–2 W. The hard parts are the clearance seal (lap or use glass/graphite) and tuning the two resonances; everything else is on this shelf.