Even heating the space station takes place by directly using solar radiation, more specifically, according to the principle of heating air simultaneously with ventilation.
Figure 80. Schematic representation of a ventilation system. The cooled and heated pipes could be built, for example, similar to the ones shown in Figure 75, D and/or K.
[TRANSLATOR'S NOTE: THE ORIGINAL SHOULD READ FIGURE 77.]
Key: 1. Used air from the rooms of the space station; 2. Fan; 3. Dust filter; 4. Dust separation; 5. Cooled pipe; 6. Cooled by radiating into empty space; 7. Heated pipe; 8. Heated by solar radiation; 9. Mixer; 10. Water and carbon dioxide separation; 11. Heating the air to the required temperature; 12. Oxygen and water supply; 13. Regenerated and heated air to the rooms where it is consumed.
For this purpose, the entire air of the space station is continuously circulating among the rooms requiring it and through a ventilation system where it is cleaned, regenerated, and heated. A large, electrically driven ventilator maintains air movement. Pipelines necessary for this process are also available. They discharge through small screened openings (Figures 60 and 61, O) into the individual rooms where the air is consumed. The ventilation system (Figure 80) is equipped similarly to the air renewing device suggested by Oberth. At first, the air flows through a dust filter. Then it arrives in a pipe cooled by radiating into outer space; the temperature in this pipe is lowered gradually to below 78° Celsius, thus precipitating the gaseous admixtures; more specifically, first the water vapor and later the carbon dioxide. Then, the air flows through a pipe heated by the concentrated rays of the sun, thus bringing it to the temperature necessary to keep the rooms warm. Finally, its oxygen and moisture contents are also brought to the proper levels, whereupon it flows back into the rooms of the space station.
This process ensures that only the oxygen consumed by breathing must be replaced and consequently resupplied from the ground; the non-consumed components of the air (in particular, its entire nitrogen portion) remain continually in use. Since the external walls of the space station do not participate in this heating procedure, these walls must be inhibited as much as possible from dissipating heat into outer space through radiation; for this reason, the entire station is highly polished on the outside.