P1. Building Integrated Photovoltaics > Outcomes 

• The highest overall conversion efficiency (sunrise to sunset) was achieved using single-crystalline cells. The insulated single-crystalline panel efficiency was 3.8 % lower than the non-insulated panel, 9.9 % versus 10.3 %. The polycrystalline panels differed by 3.1 %: 9.4 % for the insulated panel compared to 9.7 % for the non-insulated panel. The non-insulated and insulated silicon film panels converted 6.0 % and 5.8 % of the incident solar energy into electrical energy, a 3.3 % difference. Finally, the addition of insulation to an amorphous silicon panel improved the panels' efficiency from 5.9 % to 6.0 %.
  
• The parameters that have resulted from this research were incorporated into the IV Curve Tracer and PHANTASM models.
  
• Table 3 shows that savings predicted by the DOE 2.2 simulation model ranged from about $450 to $1200 per year based on a south-facing, unshaded vertical array with a gross area of about 1050 sf.
  
• Self-shading, or shading from other buildings or vegetation will reduce the savings, in some cases substantially, due to BIPV circuitry. Power production from PV panels is sensitive to the way in which the panels are circuited. Panels wired in series tend to produce less power when partially shaded compared to panels wired in parallel. Series wiring allows higher voltage output, which is advantageous in matching loads, particularly in commercial applications.

Table 3 Predicted Electrical Energy Savings for 1050 sf PV Array Mounted on a Curtain Wall

Market Outcomes:

Past obstacles to the proliferation of BIPV include the lack of validated computer simulations to predict the electrical performance of BIPV and an insufficient database on how well these products perform. Economic decisions regarding the use of BIPV are dependent upon the availability of product performance data, especially under representative field installation conditions. The research results from this project should accelerate the deployment of BIPV by providing high quality experimental data for the development, validation, and improvement of computer simulation tools.

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