BUILDING INTERIOR TUBES AND NONIMAGING REFLECTORS(BITNR)STUDIES

Building Interior Tubes and Nonimaging Reflectors(BITNR)solar thermal concentrators for mid-temperature applications in snow and dust regions,previously titled BIETR now include non-evacuated tube-receivers.A nonpublic walk-in solar collector space has fixed receiver-tubes with matching involute(rounded W)reflectors forming target-rectangles for augmenting large CPC troughs and relaxed tracking E&W‘wing’reflectors with a glass or solid polycarbonate building envelope collector cover.Reported is a BITNR reflector‘wings’tracker invention by George Helmholz and proof-of-concept development by university undergraduate engineering students.Discussed are:building types,structure,and construction and reflector materials for global applications.BITNR architectural feasibility studies with air and water-steam systems include:small wood frame structures,two-car garages,house size demonstration,long-span atriums,large concourses,towers,additions,and verification-test facilities.Schematic studies indicate integrated solar thermal mid-temperature technologies with building-size nonimaging CPC reflectors are main organizing factors for building design and site planning.BITNR/BIETR undergraduate student mechanical and structural engineering semester projects at the University of Wisconsin-Platteville are reported.A BITNR R&D project proposal is outlined which includes:a greenhouse test facility,evaluation of test stands,and development of a computer simulation design aid for architects.

SMALL HELIOSTATS CSP SYSTEMS ON LONG-SPAN HANGING ROOFS

Building Integrated Concentrating Solar Power (BI-CSP) schematic studies with small scale exterior two-axis tracking heliostats anchored on and semi-shading long span hanging roofs with elevated receiver(s) are presented for populated urban and rural locations. Hanging roofs (inverted shallow dome shape) with two-way structural cables and mostly square infill prefabricated slabs/panels supported from a perimeter horizontal circular donut shape rim-girder-platform without a center tension ring studies are for comparing to radial cable structural configurations with a center tension ring. Cable gap grouting between slabs/panels form a pre-tensioned inverted shell structure after temporary weights are removed. Securing vertical heliostat posts studies include: three vertical bolts cast in grout gap two-way cables intersections for three point adjustment of horizontal post base plates;and one-axis adjustable manu­factured post brackets bolted to sloped roof surfaces at holes cast in the gaps/slabs. A main case study schematic is around a 30m/100ft diameter hanging roof with a 0.07 sag/diameter ratio with around 271 1m2 heliostats for 230kWt solar thermal steam or air to around 300degC/572degF building integrated thermal energy storage (molten salt, firebricks, etc.) and applications (water purification, cooling, industrial process heat, etc.). A BI-CSP hanging roofs R&D project proposal is outlined: with a circular roof study diameter range of around 25m/82ft-200m/656ft diameter for comparing two-way and radial cable structural configurations for distributed steam stations and a wide range of application temperatures.