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Projects Updates for KCPA Rooftop Solar Feasibility Study

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  1. previous project description in portal

    Associated Project(s): 

    The University has been examining the benefits and possibilities of installing a solar photovoltaic (PV) systems on one or more of the roofs at Krannert Center for the Performing Arts (KCPA) and the use of photovoltaic glass units (PVGU) in the Great Hall on the west curtain wall. Phase 1 of the study has already been conducted and the University has chosen to further consider the PV system through Phase 2 of the study, which involves evaluating the structural load of the PV system, considering the acoustic impact of the PV system, and an assessment of the existing roof.

    The budget for this project has also been established. Construction would be $585,000 -- of that $457,00 would be for the purchase and installation of solar panels and electrical work and $128,000 would be spend on general construction and construction access. The payback estimated by this budget cost is substantially longer than 25 years, but the roof would require no additional cost to the University upon completion of construction.

  2. excerpt of study regarding structural analysis

    Associated Project(s): 

    The existing structure was assessed based on the original 1966 drawings prepared by Lev Zetlin and Associates (see Appendix A). The current roof structure consists of a 6 in. reinforced concrete slab supported by steel trusses that span 84 ft across the Great Hall. The trusses are made up of teeshaped chord members and double-angle web members. Secondary wide flange beams spaced at approximately 21 ft span between the trusses and create two-way action in the slab. Analyses conducted during Phase 1 of this Feasibility Study showed that the secondary components (roof slab and beams) do not have sufficient capacity to support the added load of the photovoltaic array. Consequently, support systems were conceptualized that would deliver the new loads directly to the trusses. Analyses conducted during Phase 2 therefore focused on the roof trusses.

    Loads and stresses on the trusses were determined using the American Society of Civil Engineers (ASCE) 7-10 design loads and typical material weights. Taking into consideration the dead loads (truss members, roofing materials, concrete slab, catwalks, and ceilings) and snow loads, the total load on the roof structure is estimated to be 130 lbs per sq. ft (see table below). With a distance of 21 ft-4 in. between trusses, this equates to approximately 2,800 lbs per lineal foot applied to the truss.

    • Existing Load Summary - Load (lb/ft2)
    • Truss (Self)                                     10
    • Slab                                                   75
    • Catwalks and Ceilings                   13
    • EPDM Roof                                       5
    • Insulation                                          3
    • Live Loads (Snow)                         25
    • Total                                                131 lb/ft2

    Using structural analysis software and hand calculations, it was determined that the members of the existing roof trusses labeled T-3 in the original drawings do not meet the current structural steel code for compression capacity under these load conditions. At the time of original construction, the members met requirements called for by the applicable code, the American Institute of Steel Construction (AISC) 6th Edition Steel Construction Manual. The AISC Steel Construction Manual has since been updated to account for torsional and flexural-torsional buckling and strength limitations of slender elements within members.

    The trusses were also analyzed for the addition of the PV cells and accompanying concrete knee walls. The weights of these materials and associated snow drifting loads would apply an additional 30 lbs per sq. ft (see table below), or approximately 665 lbs per lin. ft to the T-3 trusses at the locations of the new walls.

    • Additional Load Summary - Load (lb/ft2)
    • Concrete Wall                                    18.75
    • Photovoltaic Cells                               5
    • Snow Drift                                            7        
    • Total                                                    31 lb/ft2

    These loads would introduce an additional sixty thousand pounds (approximate) into each of the steel chord members, causing four additional chord members to be stressed beyond code-prescribed limitations

  3. Feasibility Study Report

    Associated Project(s): 

    This Feasibility study considers the potential placement of a Photovoltaic array on the roof of Krannert Center for the Performing Arts (KCPA). The Study was conducted in two phases, the reports of which are included herein. A construction budget of five hundred eighty-five thousand dollars ($585,000), excluding contingencies, was proposed by the Student Sustainability Committee.

  4. Summary of study results

    Associated Project(s): 

    This Feasibility study considers the potential placement of a Photovoltaic array on the roof of Krannert Center for the Performing Arts (KCPA). The Study was conducted in two phases, the reports of which are included herein. A construction budget of five hundred eighty-five thousand dollars ($585,000), excluding contingencies, was proposed by the Student Sustainability Committee.

    Based on shadow studies, it was determined that placement of a photovoltaic array on the roof of the Great Hall would maximize the potential power gain, as compared to other locations at KCPA. However, structural analyses have shown that the roof structure would require strengthening prior to the application of any new load. Additionally, based on its age, it is recommended that the roofing be replaced prior to the installation of a photovoltaic array. Access to the roof is cumbersome, and is also in need of improvement. The opinion of probable construction cost for this associated work exceeds the five hundred eighty-five thousand dollar ($585,000) construction budget. Without considering these associated projects in the payback analysis, the complexities of constructing a PV array on the roof structure diminish the economical effectiveness of a roof mounted PV array as compared to a ground-mounted system, assuming the ready
    availability of real estate.

    Based on these findings, it is the recommendation of Hanson Professional Services Inc. (Hanson) that a photovoltaic array not be placed on the roof of the Great Hall at KCPA, and that consideration be given instead to directing the available funds to a location that is more readily suited to its construction.

  5. Krannert Center seeks solar funding

    Associated Project(s): 

    The Krannert Center for Performing Arts is seeking funding from the SSC for solar installations on their building.  They will be submitting a full proposal to SSC in March, and they will work with sustainability staff to submit a DCEO grant application under the Program Year 2013 Renewable Energy Production Program.

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