Can a hall with a sandwich panel roof use building-integrated photovoltaics?

A roof panel carries loads, limits heat loss and keeps water out at the joints. Further requirements apply to the roof assembly as a whole.

A steel photovoltaic panel can serve as the roof covering, but that does not mean it takes over every function of an insulated sandwich panel. It generally requires its own supporting structure and build-up. Even if both products have a metal exterior, compare what the complete roofs do, including the layers underneath the surface facing the sun.

Many industrial roofs have a shallow pitch. The proposed BIPV system may require a steeper minimum pitch because its joints shed water differently. A minimum pitch specified for the sandwich panel cannot be applied to an integrated covering with a different joint design.

Roof slope length, flashings and local ponding also matter. Extra sealant cannot correct unsuitable roof geometry. If the slope falls outside the system’s application limits, choose another solution before ordering panels for the site.

Direct attachment requires fixing details and an assessment of the whole assembly. The facing is designed to transfer loads in a particular way. Additional wind uplift, concentrated forces and new penetrations may change that behaviour. The arrangement must meet the structural design requirements and those of the manufacturers whose components will be used together.

This applies to mechanical fasteners and bonded joints alike. Avoiding drilled holes is no guarantee that a joint is adequate. Check its durability, operating temperatures, relative movement and repair options. If a finished covering remains beneath a separate array, that array is a roof-mounted system. Building-integrated photovoltaics serve a building function themselves.

Replacing the covering can change how heat and moisture move through the roof. If a sandwich panel is removed, the new build-up must provide the functions it used to perform. Photovoltaic cells do not replace thermal insulation. The design must also address fire protection and the hall’s intended use for the complete assembly.

A classification for an individual module or sandwich panel does not automatically cover their combination. Check what was tested and the permitted scope of application. Commercial buildings also have maintenance, insurance and equipment access requirements. Gather these before choosing the roof system.

An office, showroom or service wing next to the hall may have its own pitched roof. That slope may suit the chosen BIPV system better. The integrated covering can then perform its intended function without having to adapt it to the hall roof. It may also supply loads elsewhere on the premises if the electrical design provides for that connection.

Before counting on power from one building supplying another, check the electrical layout and the applicable metering and billing arrangements. An integrated covering may give a customer-facing office a consistent roof appearance. This can be a practical reason to choose the office slope even when the other buildings retain their existing roofs.

Start with the specifications for the existing panels, frame and roof geometry. Then set out the energy objective and the planned extent of the refurbishment. Ask the designers to compare retaining the covering and adding a separate array with providing a new active covering on a suitable slope. For each option, establish how the assembly will be attached and how it will carry loads.

An integrated roof is particularly useful where a new covering is needed anyway and can also generate electricity. For a sandwich panel hall, the first decision is whether the proposed assembly is suitable and documented. Once that is established, compare appearance, cost and expected energy yield.

Manufacturers and brands in photovoltaic roofing include Autarq, ML System, 3S Swiss Solar Solutions, SolRoof, SunRoof, Wienerberger Wevolt, Electrotile, MDM NT (MyRoof), Terrán and Nelskamp.