Building-integrated photovoltaics

Building-Integrated Photovoltaics  (BIPV) is a concept which is increasingly gaining momentum in the recent times. BIPV are photovoltaic materials which are used to replace the conventional building materials in various parts of the building (like roof , facade, etc .). They are increasingly used in construction inorder to meet the energy demands with the effective use of the available area.This is one among the green building concepts.

CIS Tower in Manchester,England

BIPV Installations :

Roof tiles and shingles :
Solar facades, curtains, awnings, and windows :
    

                                                        

On par with BIPV there is another synonymous term BAPV ( Building Applied Photovoltaics) where the photovoltaic materials are retrofitted into the building only after the completion of the construction. BAPVs are mostly mistaken as BIPVs. Only in certain preplanned and economically viable cases BIPV are efficiently constructed.

The chief component of the BIPV is the PV module .The PV modules are properly electrically cabled in series and parallel to form the array.The DC power generated is stored in batteries ,converted to AC via an inverter and then used.

Market available BIPV are grouped into two categories : facade systems and roofing systems.Facade systems include curtain wall products, spandrel panels, and glazings. Roofing systems include tiles, shingles, standingseam products, and skylights.

The fundamental step in any BIPV application is to maximise energy efficiency and holistic utilization of the available solar energy.Windows, skylights, and facade shelves can be designed to increase day lighting opportunitiesin interior spaces. PV awnings can be designed to reduce unwanted glare and heat gain. This integrated approach, which brings together energy conservation, energy efficiency, building envelope design, and PV technology and placement, maximizes energy savings and makes the most of opportunities to use BIPV systems.

This concept has its root in the early 1970s when aluminum  foil framed panels were mounted in remote areas with no accessibility to power. Patrina Eiffert's doctoral thesis in 1998 was the next big leap. The concept came to lime light in 2011 when the U.S. National Renewable Energy Laboratory made a brief overview.

The advantages of BIPV system include Energy generation, UV & IR filtration ,Thermal & acoustic insulation , Natural illumination , Reduction dependance on grid and Reduction in carbon-di-oxide emission. Transparent and translucent panels are also available which aid in natural illumination.

Government subsidies and incentives are available in various countries to encourage BIPV. France, Germany , Italy , Spain , U.S.A. , China are a few noteworthy countries with regards to BIPV.

* CIS Tower in Manchester,England

* Norwegian University of Science and Technology

* Pearl Harbor Naval Station,Honolulu, Hawaii

* Photovoltaic facades in Tübingen and Freiburg

The largest Photovoltaic Skylight in the World is at Novartis Pharmaceuticals in New Jersey built by Onyx solar.

Conventional solar panels are normally retrofitted onto the rooftops with  special mounting structures.BIPV can overcome this . One of the easiest places to begin for a broad-scale implementation of BIPV is in ceramic or clay roof tiles, which are rigid and flexible. Tile-type modules which are frameless, of regular size,  different functionality, such as thermal collectors and skylights, as well as standard roof tiles are also available in the market. 

Another way that photovoltaics can be integrated into a building is in the walls of the building itself, or sometimes more effectively, in a multi-purpose ‘skin’ or curtain that surrounds the ‘core’ building inside of it.In other words, it is not absolutely necessary that modules be placed on the roof.

* Integrating into the walls : Perfectly vertical walls do not receive much radiation as the horizontal and sloppy walls do. But a part of energy can be absorbed and is useful in winter when the sun comes at lower angles.

* Integrating into the buildings' s skin : Some buildings incorporate such a skin for aesthetic as well as for climate control purposes. If the panels were, much like windows, capable of opening and closing, they could play a direct role in controlling the climate of the building, while at the same time having enough space to keep cool and therefore function efficiently.

     

* Solar Awnings :  Solar awnings keep the unwanted rays away from eyes and efficiently absorb the rays which are necessary to generate electricity.The angles of the awnings can be adjusted in accordance  to the climate.

                                                      

* Solar Windows :    Solar windows and glazing serve the common purpose of letting the light in , reducing the glare , providing ventilation and insulation.