The solar technology of the Kender Engine (Phase 4)
In the heat exchanger, the helium moves from its very low temperature back up to 20 C° (69 °F) by heating due to the temperature of the air surrounding the solar panel (Phase 4).
As the helium moves back up in temperature from -240 C° to 20 C°, its pressure builds back up to 200 atmospheres (Phase 4).
This is again the application of the law of perfect gases (Pressure * Volume = N * r * Temperature). The surrounding air, obviously, will drop in temperature, as it transfers its thermal energy to the helium.
