A refrigeration system is provided. The refrigeration system includes at least one thermal blocking thermotunneling device. The thermal blocking thermotunneling device comprises a first and a second surface separated by a nanoscale gap of less than about 20 nm, such that tunneling of electrons causes a unidirectional transfer of heat from the first surface to the second surface. Further, the at least one thermal blocking thermotunneling device has a thermal back path of less than about 70 percent.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
 This invention was made with Government support under contract number DE-FC26-04NT42324 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.