Patent ID: 8281783

Claim:
A thermal absorber comprising: a light-transparent reservoir having an alkali metal received therein; a housing sealingly coupled to said reservoir to define an enclosed volume, said housing including a thermal barrier wall that divides said volume into a cold chamber and a hot chamber, said thermal barrier wall including a sump in said cold chamber having a drain hole in fluid communication with said hot chamber; at least one alkali metal thermal-to-electric converter (“AMTEC”) cell supported by said thermal barrier wall, said AMTEC cell extending through said cold chamber and said hot chamber; and a support structure connected to orient said housing such that at least a portion of said cold chamber is at an elevation above at least a portion of said hot chamber, and said sump is positioned at a relatively lower elevation portion of said cold chamber such that said alkali metal condensing in said cold portion flows downwardly along said thermal barrier wall by gravity to collect in said sump, and flows from said sump through said drain hole by gravity to said hot chamber.