Hot water supplies account for approximately 30% of energy consumption in residential sectors of Japan; it is therefore important that the energy efficiency of water heaters be improved. Absorption heat pump water heaters are expected to provide greater efficiency than conventional water heaters that use gas. However, the absorption systems have larger volumes and are not widely accepted in the...

It is well known that the efficiency of thermodynamic solar plants increases with the working temperature. At present the main limit in temperature upscaling is the absorber capability to withstand high temperatures. The ideal solar absorber works at high temperatures, has a low thermal emissivity and a high absorptivity in the solar spectral range . The paper reports on the high temperature em...

Mathematical description of a passively Q-switched laser and the way it works are presented. Both theoretical and experimental model of this laser have been worked out. Moreover, numerical analysis of saturable absorber influence on laser efficiency was made. It is the saturable absorber characterized by excited state absorption (ESA) that has been taken into account. The optimization procedure...

We present theoretical considerations as well as detailed numerical design of absorber and emitter for Solar Thermophotovoltaics (STPV) applications. The absorber, consisting of an array of tungsten pyramids, was designed to provide near-unity absorptivity over all solar wavelengths for a wide angular range, enabling it to absorb light effectively from solar sources regardless of concentration....

The design and simulation of a wide angle, spectrally selective absorber/emitter metallic photonic crystal (MPhC) is presented. By using dielectric filled cavities, the angular, spectrally selective absorption/emission of the MPhC is dramatically enhanced over an air filled design by minimizing diffraction losses. Theoretical analysis is performed and verified via rigorous coupled wave analysis...

The performance of the Cu2ZnSnS4 based solar cell is investigated using a simulation program called Solar Cell Capacitance Simulator (SCAPS). The cell structure is based on Cu2ZnSnS4 (CZTS) compound semiconductor as the absorber layer, n-doped and un-doped (i) zinc oxide as the window layer, In2S3 as the buffer layer. We study the influence of the defect density, carrier density, thickness of t...

Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customi...