The Greenstone Government of Canada Building features a unique Building Integrated Photovoltaic (BIPV) system which is the first installation within a preglazed advanced curtainwall system. Photovoltaic elements are sandwiched between two layers of glass in the exterior element of a high-performance four-part curtainwall system. Designed for a cold climate application, it is the largest curtainwall-integrated BIPV system in Canada. The BIPV component was designed to replace the need for external shading and to generate electricity in the glazing of the south facing atrium.

This project was awarded a Royal Architecture Institute of Canada Awards of Excellence - Innovation in Architecture for the success of the BIPV systems.

Finances

There was no additional capital budget available for the BIPV. Simple preliminary budget calculations suggested that the base budget for the Greenstone Building, minus the cost of the sunshades, plus the TEAM funding could balance the capital budget. The high-performance curtainwall was already included in the budget, and so it was just the PV array, with all its electrical inverters, controls and systems, that was added to the project scope, while sunshades were deleted.

Innovation

The innovative BIPV cells have a unique crystalline appearance from the outside, and a square grid appearance from the inside. The shading elements that were originally designed into the building created a layered, or veiled appearance on the south side. The new photovoltaics appeared more bare and monolithic.

In order to integrate the need for daylight and shade, the need for views through the glazing, and the need to balance the monotony of the photovoltaics, a striped pattern was selected. Alternating bands of PV glazing and clear glazing give the south elevation of the GOCB an appearance of layers, despite the lack of shading devices.


Lessons Learned

The BIPV is performing well so far. The shading function works really well, and there have been no complaints of overheating in the atrium. The BIPV provides an attractive level of light and shade in the atrium, and it demonstrates that PV arrays can be incorporated into glazing on the south site of northern buildings. The appearance of the interior is attractive. The exterior appearance could be refined, and should in future be studied more carefully. The technical challenges were overcome, each in turn, through the collaboration between the team at NRCan, PWGSC, Visionwall, Manasc Isaac Architects, and Keen Engineering.

Integrating PV arrays into high performance curtainwall systems is challenging and depends on the goodwill and collaboration of a lot of different parties. Significant reductions in greenhouse gases and purchased energy can be achieved and the many institutional, technical and economic barriers will require far more work to enable this innovation to go mainstream.


For more information about this and other Lessons Learned from the Greenstone Building, download the Post Occupancy Evaluation.