|Integrating photovoltaic systems in buildings (BIPVs) is an attractive method of:
BIPVs are manufactured from various PV cell types (i.e. crystalline or micro-perforated amorphous silicon ) and may be utilized as construction materials.
- reducing energy consumption from fossil fuels
- utilising surplus solar energy for energy generation and direct usage when possible
- providing shelter from glare and overheating
BIPVs as well as PV modules are manufactured using low iron tempered glass. Glazings consist of simple glass /glass laminate or a complex isolation glass /glass laminate. Due to safety requirements concerning lamination PVB (Polyvinyl Butyral) is usually preferred instead of EVA foil. Especially in case of transparent roofs, PVB has been proven safe after decades of use in the automotive industry for laminated safety windscreen manufacturing.
BIPVs may replace:
- Conventional roof tiles
- Wall /Curtain Wall materials
- Glazing membranes
- Shading devices
- Double façade elements
BIPVs have been increasingly incorporated into new buildings but also constitute an effective alternative in regard to retrofitting measures in refurbishment projects via face lift.
The main advantage is that conventional building fabric materials are spared and no extra labour is required (which 'in theory' partially offsets the BIPV mounting and installation cost). BIPVs may also contribute regarding the heating requirements although increase the cooling demand since solar thermal gains will be re-emitted partly internally by the dark coloured panel internal surfaces.
Well-designed system architecture can make the best out of the available solar energy!
- electricity is generated locally (hence avoiding distribution losses) and embedded carbon emissions regarding standard fossil fuels are minimised.
- photovoltaic cells are incorporated directly on the building construction elements reducing balance of system (BOS - DC wiring) costs.
- BIPVs incorporated in the building fabric could minimise costs of PV roof mounting elements even though inclination angles are far from optimum in regard to maximisation of electricity yield.
- BIPV's are an additional option when there is no space on the roof.
However overheating of PV cells when installed on building surfaces is still an issue under consideration ¹. Building contractors are currently still confused regarding costing this newly introduced type of work, which often results to PV suppliers having to introduce "specialised" crews for fitting the systems. This almost leads to double construction costs.