Integrated photovoltaic system for sloped roofs (2) Three types

Currently on the market Integrated photovoltaic system for sloped roofs There are many products and solutions, each with its own characteristics. The author divides them into three types: tray type, component waterproof type, and photovoltaic tile.

Photovoltaic roof case, reference article: Roof photovoltaic collection (4 ) A residential roof photovoltaic project in the Netherlands (Picture: Exasun)

1️ ⃣   Tray-type system

This type of system is characterized by a waterproof tray made of metal or plastic plates under the photovoltaic modules, forming the first waterproof layer of the roof. The tray is fixed on the hanging tile strips, and the seams between the tray and the roof tiles and the seams between the trays have corresponding waterproof measures. The photovoltaic modules are placed on top of the tray and fixed by rails connected to the tray or the concave-convex structure of the tray itself.

The tray-type system decouples the waterproof and energy attributes of the photovoltaic roof. The waterproof function mainly relies on the tray. When selecting photovoltaic modules, there is no need to consider waterproofing, but mainly focus on its power generation performance and price; some trays also act as a bridge between the building modules and the photovoltaic product size, which is a design concept worth paying attention to! Its main advantages are: it has the appearance advantage of photovoltaic modules embedded in the roof, and because it is compatible with mainstream photovoltaic modules, it has cost and power generation performance advantages, and it is also conducive to the disassembly and replacement of photovoltaic modules during maintenance.

Because EU manufacturers are far behind Chinese companies in the technology, performance, and cost of photovoltaic modules, the tray-type system allows them to make the best of their strengths and avoid their weaknesses, design trays based on a deep understanding of local building codes and roof structures, and match mainstream Chinese photovoltaic products to form a competitive photovoltaic roof system.

Tray-type photovoltaic roof case, reference article: Roof photovoltaic collection (10 ) French campus roof photovoltaic  ” (Picture: GSE)

2️ ⃣   Component waterproof system

The component waterproof system is characterized by using photovoltaic modules as the first waterproof layer of the roof. There are special waterproof measures at the seams between adjacent photovoltaic modules, such as specially designed photovoltaic module frames or special profiles suitable for frameless photovoltaic modules. Some systems use the method of overlapping photovoltaic modules up and down, and set sealing strips at the overlapping parts to enhance the waterproof performance. At the seams between the photovoltaic modules and the roof tiles, waterproofing is achieved by installing flashing boards.

This type of system has a higher degree of integration than the tray-type system. The photovoltaic modules can use mainstream specifications or similar sizes, and the mold cost of the module frame or profile is low, so the overall cost of the system is also relatively low. After the installation of the component waterproof photovoltaic roof, the ventilation cross-section on the back of the photovoltaic module is relatively large, which is conducive to module heat dissipation.

The component waterproof system appeared earliest among the three types of systems, and many companies are still working hard on this technical route, which can be said to be enduring!

Component waterproof photovoltaic roof case, reference article: Roof photovoltaic collection (13 ) German rural roof photovoltaic   (Picture: Solrif)

3️ ⃣   Photovoltaic tile system

The main difference between the photovoltaic tile system and the above two systems is that the photovoltaic modules are made into the form of tiles. Not only is their shape similar to tiles, but the size setting is mainly based on the standard size of tiles rather than the size of photovoltaic glass or crystalline silicon cells. Photovoltaic tiles have various shapes such as flat plates, curved surfaces, and cylindrical tiles. Each shape of photovoltaic tile can usually only be used with ordinary tiles (matching tiles) of the same shape, while the other two types of integrated systems do not have this limitation.

Photovoltaic tiles usually use overlapping waterproofing similar to roof tiles. In order to reduce costs, the overlapping width of photovoltaic tiles may be much smaller than that of roof tiles. In this case, waterproof strips and buckles should be used to enhance the waterproof and wind resistance of the system. Because the form of photovoltaic tiles is similar to ordinary roof tiles, the installation method is relatively easy for roof workers to learn and master.

There are many manufacturers in the photovoltaic tile track, which can be roughly divided into two schools: one is that previous building materials companies, especially tile companies, have transformed into photovoltaic building materials, and have developed photovoltaic tile systems combined with their own tile roof systems; the other is photovoltaic companies entering the building materials market, using photovoltaic technology or supply chain advantages to develop photovoltaic building materials. Although the domestic real estate market has been sluggish in recent years, tile roof buildings, as one of the mainstream residential building types used worldwide, will have a long-term market; this may be the confidence and expectation of photovoltaic tile manufacturers for the future.

Photovoltaic tile roof case, reference article: The 10th International BIPV Building Competition Award-winning Works Appreciation (Four) (Picture: Megasol)