This is bullshit (specifically, a perpetual motion machine of the 2nd kind). Suppose you have a heat source T_H in an environment T_C. If you could extract mor

This is bullshit (specifically, a perpetual motion machine of the 2nd kind). Suppose you have a heat source T_H in an environment T_C. If you could extract more work from the thermal radiation of T_H than the Carnot limit for this system, you have enough work to run a Carnot heat pump from T_C to T_H that increases the temperature of T_H, and decreases the temperature of T_C -- an violation of the 2nd law. You could use work to increase the heat source's temperature, leading to more work, leading to higher temperatures, in perpetuum. No can do!