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BAPV vs BIPV : what are the differences?
For some years now, equipping a building with a photovoltaic module has not just been about superimposing a solar installation on an existing roof. Now it is possible to integrate photovoltaic equipment right from the design phase of the building by treating it as a completely separate construction element, thereby maximizing the aesthetic qualities of the architectural project.
What distinguishes a BAPV from a BIPV installation?
These two solar installation integration techniques share the feature of being used in the construction industry. In both cases, the objective is to make surfaces active, including sloping and flat roofs (tiles, metal panels and waterproofing membranes), facades, sunscreens, guard rails and skylights.
The main difference between BAPV and BIPV is the way they are designed and integrated into the building in question:
- The BAPV (Building Applied Photovoltaics) method consists of fitting modules to existing surfaces via superimposition once construction has been completed, such as during an energy renovation project. This is the approach adopted for traditional photovoltaic solutions.
- The BIPV (Building Integrated Photovoltaics) method includes the replacement of the traditional construction element with materials incorporating solar modules. This offers a dual function, namely to produce energy and to provide a construction element for the finished building. The second technique can be employed at any time, right from the start or during the construction project, or afterwards in the event of a section of the building being renovated (roofs, windows, cladding, etc.). This is the favored approach when designing an "active" architectural product.
Did you know?
The European regulation covering construction products (CPR 305/2011) specifies 7 fundamental requirements applicable to construction projects in order to assess performance (energy efficiency and thermal insulation; mechanical resistance and stability; fire safety; hygiene, health and the environment; safety and accessibility in use; noise protection; sustainable use of natural resources). Consequently, deciding to use photovoltaic modules improves energy performance - all the more so if using the BIPV method thanks to the dual functionality of the technique.
Where is the BIPV technique used most?
In urban areas, only exploiting the surfaces of building roofs remains limited as it has generally been favored, for reasons of space constraints, to construct tall buildings on smaller plots. Terraces are increasingly becoming favored social areas, leaving less room for technical equipment. The ideal is therefore to opt for integration of equipment that can be used on as many available surfaces as possible and which is easy to install. Lastly, in urban areas where maintaining the aesthetic qualities of spaces is an important issue, BIPV also has the advantage of making the presence of photovoltaic modules more discreet. Given these objectives, the BIPV integration method is increasingly becoming the ideal solution to be applied in urban areas.
The expert's view – Denis Bourène, Business Development Manager at ASCA® Structures
Denis is responsible for ASCA® photovoltaic films within the ASCA® Structures market segment of the ARMOR group, focusing on the construction sector.
If we had to state one feature out of all the properties offered by the ASCA® film, it would be its low-carbon impact. Analysis of the life cycle over 25 years reveals a carbon footprint some 5 or 6 times lower than a silicon-based photovoltaic installation. In France, certain projects put through the "E+C-" test (a building block of the next environmental regulations) have not been able to incorporate solar production as silicon cells make it impossible to achieve the carbon objective! Accordingly, the ASCA® film has a prominent place in BBCA certification for low-carbon buildings. The low-carbon footprint argument for a sector such as construction, which is responsible for more than one-third of greenhouse gas emissions worldwide, is therefore an essential factor in the fight against climate change.
On what types of surface can the ASCA® photovoltaic modules be integrated?
The ASCA® film has been designed to be integrated on all elements of building facades and roofs. Its high sensitivity to diffuse light offers optimum production when it is exposed in different orientations, as occurs on building facades. It also produces energy at low luminosity. This means that at the same level of installed power, the daily production capacity is between 10% and 20% higher than that of a silicon-based photovoltaic technology. Whereas a traditional silicon panel stops producing below 1,000 Lux, the ASCA® film continues to produce at 200 Lux.
Its ultra-flexibility with a 2.5cm radius of curvature means it fits snugly onto the surfaces where it is applied. For example, this applies to metallic-textile structures that cover certain stadiums and to car park shade structures. Rolling and unrolling tests also confirm its ability to be deployed on winding systems such as blinds.
One important difference to other technologies is its semi-transparency. It currently stands at 30% (light transmission rate) and our objective is to reach 60%. This will enable us to combine energy production with the shade function - a major issue for all exposed glazed facades. This dual function will promote energy savings from air conditioning systems.
Is the ASCA® technology suitable for both integration methods, namely BAPV and BIPV?
The ASCA® photovoltaic technology is versatile and is just as easy to integrated within a material as to superimpose on the roof of a building, for example. Right now we are developing "ready-to-glue" photovoltaic modules that are compatible with metal, glass, polycarbonate, etc. These films are quickly and easily installed; being lightweight, a single person can easily roll them up and unroll them without taking up much time. These "ready-to-glue modules represent an ideal solution for all building energy renovation projects and for all existing buildings not designed to take an additional load.
At the same time, we are developing partnerships with construction industry companies to incorporate the film at the production stage. The aesthetic aspect and the applications in future 'intelligent' facades will play a predominant role in these new 'active' building materials being specified by architects.
What type of projects are you currently working on?
The priority is for demonstrators in order to validate behavior over time in the various planned applications and to spread the word about the potential of OPV technology. First of all on industrial greenhouses, with applications applied to glazing and shading. And we are also involved in projects covered by the French Labor Code and by ERP public building regulations. We take part in work involving roofing, metal cladding, curtain walls, skylights and waterproofing membranes. At the same time, we are also engaged in certification initiatives. The objective is to gain IEC (International Electrotechnical Commission) approval and ATEx technical experimentation assessment during 2020, which will enable us to install our film with all the guarantees demanded by insurers.
At what point of the construction project should you be contacted?
It is important for planners and clients to establish a program that promotes or favors the use of innovative low-carbon photovoltaic solutions. The message is therefore initially addressed to them. Subsequently, developers, builders then architectural and engineering teams must include them in their submissions or proposals. This requires contact being established with our teams at a very early stage of the project. In operational terms for both construction and renovation projects, the earlier we are involved in the project (from the first architect's drawings) the more the building's solarization potential can be optimized. Our design department can help the project manager select the most suitable substrate materials and applications depending on the required outcome.