Abstract: A flow battery includes a membrane having a thickness of less than approximately one hundred twenty five micrometers; and a solution having a reversible redox couple reactant, wherein the solution wets the membrane.

Abstract: A combined vapor compression and vapor expansion system uses a common refrigerant which enables a super-critical high pressure portion and a sub-critical low pressure portion of the vapor expansion circuit. Provision is made to combine the refrigerant flow from the vapor expander and from the compressor discharge. The outdoor heat exchanger is so sized and designed that the working fluid discharged therefrom is always in a liquid form so as to provide a liquid into the pump inlet. The pump and expander are so sized and designed that the high pressure portion of the vapor expansion circuit is always super-critical. A topping heat exchanger, liquid to suction heat exchanger, and various other design features are provided to further increase the thermodynamic efficiency of the system.

Abstract: A thermophotovoltaic electricity generating system having a heat source generating a thermal emission having a plurality of wavelengths. There is an optical filter filtering the thermal emission into a filtered emission. There is also a thermophotovoltaic device receiving the filtered emission. The thermophotovoltaic device is configured to absorb the thermal emission converting the thermal emission into electricity.