Reply To: turn heat into electricity

[Henning]

Somewhere else in this forum I’ve suggested Kapton (aromatic polyimide) as a possible insulator.

German Wikipedia says aluminium oxide has a dielectric strength of 35 kV/mm.

Kapton has a much better dielectric strength (150-300 kV/mm, table 7 of PDF). Some more details are in http://www2.dupont.com/Kapton/en_US/assets/downloads/pdf/summaryofprop.pdf

But also see figure 8 “Retained Dielectric Strength at 325°C (617°F) for 25 µm (1 mil) Film” and figure 14 “AC Dielectric Strength vs. Temperature”. The temperature was applied continuously, so the aging shouldn’t be such a big problem in a pulsed environment. (Maybe it is, because of mechanical strain.)

Kapton is sold as sheets, but it’s also available as tubes, for example at http://concentrictube.com/ . Maybe they know how to manufacture them as hats.

On the other hand, if it’s such a good material, the other DPF scientists would have used it already. So maybe this suggestion isn’t that useful at all…