Thermal Control Using Multi-Spectral Switching

When radiation is the primary mechanism controlling temperature, both the solar absorption and the radiation must be controlled. One method to change the radiated energy is to change the emissivity near the peak of this radiation. If the internally generated heat varies, active control on this emissivity is necessary which must be coupled with additional control on the energy absorbed from solar radiation. This proposal provides this active control with a new and novel approach. It provides independent switching of the LAIR emissivity and the visible absorption. This dual control gives a degree of thermal control previously unattainable. The approach is based on an electrophoretic/electrochromic system with a special pigment to minimize absorption in the binder. The approach will have minimal power consumption and has calculated changes in the emissivity from .4 to .85, (averaged from .2 to 15 microns) independent of changes in solar absorption. Changing the emissivity in the IR will control the radiated heat from a surface, allowing the system to adjust for internal varying loads while the active switching of the visible radiation will control solar loading. The approach is based on an electrophoretic/electrochromic system with a special pigment to minimize absorption in the binder. The approach will have minimal power consumption and has calculated changes in the emissivity from .4 to .85, (averaged from .2 to 15 microns) independent of changes in solar absorption. Changing the emissivity in the IR will control the radiated heat from a surface, allowing the system to adjust for internal varying loads while the active switching of the visible radiation will control solar loading.