Patent ID: 8261557

Claim:
A heat transfer device, comprising: a photonic crystal comprising a periodic arrangement of first and second materials having different refractive indices that create a photonic band gap, said photonic crystal including at least one resonant defect cavity in the periodic arrangement that radiates electromagnetic energy in an emission band within the photonic band gap, said photonic crystal thermally coupled to a cold region to receive thermal energy from the cold region; an actuator that cyclically performs mechanical work on the photonic crystal by cyclically separating the photonic crystal from the cold region to cycle the photonic crystal between a first state to collect thermal energy from the cold region to heat the crystal and a second state to radiate electromagnetic energy to a hot region to cool the photonic crystal; and a mechanism that applies an external field to the photonic crystal to cycle the emission band between a first wavelength of relatively low radiance in the first state to collect thermal energy from the cold region and a second wavelength of relatively high radiance in the second state to radiate electromagnetic energy to the hot region.