Photovoltaics thermal processing

The process is potentially economical in the desert southwest United States. However, an outlet for the carbon black is an integral part of the overall economics. Compared to photovoltaic conversion and electrolysis of water to produce H2, the solar-thermal process requires 40 times less heliostat surface, and the heliostats are lower cost mirrors rather than expensive photovoltaic cells. The solar-thermal process can produce HCNG at high rates in one step by efficiently and cleanly removing carbon from fed NG. 

It is clear that the development of vapor phase epitaxy reactor at atmospheric pressure is booming. The process leads to good quality material and is compatible with the photovoltaic industry criteria of efficiency and reduced production costs. Indeed, the active layer deposition step represents the main cost of a thin cell process. Any innovation to reduce the thermal budget of this operation is of major interest. 

Other important properties for photovoltaic materials are their refractive index, stability, brittleness, toxicity, crystal lattice constant, thermal expansion coefficient, temperatures required for processing into cells, energy investment for cell production, ability to be doped both types, level of technological knowledge and industrial maturity, cost, and abundance. Issues particular to passivation and the trapping of weakly absorbed light include the availability of compatible and affordable passivation and surface texturing methods. ... 

In evaporation-intercalation devices solar energy conversion would, at least in the more efficient case of a thermal system, not be converted by exciting electrons and rapidly separating them from holes, but by transferring atoms or molecules across a phase boundary by evaporation which is usually a very efficient process. It is, consequently, neither necessary to use materials which are well crystallized like those developed for photovoltaic cells nor is it necessary to prepare sophisticated junctions. A compacted polycrystalline sheet of a two-dimensional material which is on one side placed in contact with an electrolyte, sandwiched between the layer-type electrode and a porous counter electrode, as it is used in fuel cells, would constitute the central energy conversion unit. Some care would have to be taken to choose an electrolyte which is suitable for intercalation reactions and which is not easily evaporated through leaks in the electrodes. Thin layers of polymeric or solid electrolytes would seem to be promising. 

Since there is no energy conversion processing required (i.e. no efficiency losses to convert steam generated by combustion into electricity via a turbine or to convert sunlight to electricity via a photovoltaic cell and then use the electricity to split water by electrolysis), the sunlight is directly used to drive high temperature "brute force" chemical reactions -such as dissociation reactions - at high efficiency. Overall solar-thermal efficiencies approach 50%. 

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