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.