Building Integrated PhotoVoltaics - BIPV

  

There is a myth amongst urbanites that solar energy is more suited for rural applications. While acknowledging the fact that solar energy has contributed significantly to build rural infrastructure, it can in the same vein impact the urban populace and corporates. The impact would be evident in the coming years as the relevance of energy security gains in importance.

The benefits of solar power are compelling: environmental protection, economic growth, job creation, diversity of fuel supply and rapid deployment, as well as the global potential for technology transfer and innovation.

There’s a perception among many that solar systems are very expensive. However, this is only a perception. In reality, one needs to understand the entire life cycle cost to drive home the point. Solar photovoltaic systems for generating electricity need a high initial investment but more importantly very low or negligible running cost. A solar module has a life of 25 years and delivers reliable performance throughout its life. But when one looks at alternatives such as diesel generators  that are dependent on a regular supply of fuel + maintenance + transportation + cost of replacement + noise & smoke pollution, one begins to understand the ‘Total life cycle’ cost of a systems cost advantage of solar systems with crude prices threatening to breach the previous highs, the solar energy solutions are practical, economically viable and enhance energy security.

So the idea of putting the energy of the sun to work has been around for a long time. We just need to find more ways to use it in our daily lives. One such way is called Building Integrated Photovoltaics or BIPV Technology.

Imagine the electricity-generating device has a long lifetime and low maintenance costs with no moving parts, noise, emissions, or fuel lines. Now imagine that this device is actually the walls, roof, and windows of your building the same structure that keeps out the rain, heat, snow, and cold. It's not Science Fiction! It's Building Integrated Photovoltaics, and it is a very real part of building construction today.

As green buildings connect is gaining awareness and corporates are being subjected to environmental audits, the opportunities in Building Integrated Photovoltaics (BIPV) can change the face of architecture. Solar PV (Photovoltaic) modules are aesthetically integrated into building design either on the facade or roof thereby not consuming any additional space. Such a system not only generates solar power but also allows natural light into building thereby reducing electricity demand. It also provides excellent heat insulation and helps in reducing air conditioning loads as well.

Understanding Building Integrated Photovoltaics

With Building Integrated Photovoltaics (BIPV), the photovoltaic material becomes an integral part of the building: the walls, roof, and vision glass. Sunlight falling on the photovoltaic components creates electricity. This electricity flows through power conversion equipment and into the building's electrical distribution system, feeding electricity to the building's electrical loads. In essence, the skin of the building produces electricity for the building, typically enough to power the desired load.

Most architects, engineering firms, building owners, and builders know very little about Building Integrated Photovoltaics. The majority of BIPV products exist for commercial construction, and commercial buildings can accommodate the several thousand Rupees cost required for installing even a small one-kilowatt BIPV system. The technical potential in commercial buildings is significant, and they suffer fewer problems from orientation and shading.

          

Solar glazings and laminates - From module to BIPV system

           

In photovoltaic applications (also in BIPV systems) low iron tempered glass is usually used. Glazing can be made as simple glass/glass laminate or as complex isolation glass/glass laminate. Special laminates with coloured back sides have also been produced. Due to safety requirements for lamination usually, PVB foil instead of EVA foil is used - especially for laminates used in transparent roofs. PVB has been used for decades in the automotive industry - laminated safety windscreen glass. Laminate can consist of monocrystalline cells, thin film cells or from transparent cells.

Glass/glass and isolation glass/glass laminates with solar cells

Large transparent module - glass/glass laminate. In BIPV applications different types of modules (depends on application) can be used: classic (framed) modules, flexible crystalline or thin-film on a metal substrate, roof-tiles with solar cells, transparent monocrystalline modules, modules with coloured solar cells, semitransparent micro-perforated amorphous etc.

Upon customer request, almost all module (mechanical and electrical) parameters can be customized. Customization includes module shapes, cell type and colour, cell transparency, laminate construction, laminate/module size, heat/noise isolation properties, module voltage and peak power etc. Limitation during production represents usually the only laminator - largest laminators allow production of laminates up to 5 square meters of area in one piece.

Types of BIPV Laminates (Single, Double, Triple Glass Laminates)

Facade integrated modules

Most common realized as "curtain wall", or facade mounted modules. "Cold" and "warm" photovoltaic facades possible. In BIPV facades different types of modules can be used: classic modules, transparent or semitransparent modules (crystalline or microperforated amorphous modules). "Shadow-Voltaic" system is also very often part of a BIPV facade. Modules can be fixed or mounted on tracking structures - manual tracking-combined with shadowing system, or automatic tracking systems possible.

     

Roof-integrated modules

As roof-integrated modules usually laminate without frame are used. Special types are solar roof tiles or shingles.  As roof-integrated modules, other module types can also be used for example flexible modules, transparent or semitransparent modules, thin film modules etc.            

Problems related to BIPV systems

Exact shadowing analysis should be made before the system is constructed, high-temperature conditions should be avoided by crystalline modules (decreased efficiency).

And the best part – the solar solution can be seamlessly integrated into any application. They are highly reliable and economically viable. With further improvements in technology on the cards, the possibilities with solar energy seen limitless.

For more details: Soura Natural Energy Solutions