BIPV Solar Systems: Properties And Prospective Applications

BIPV is a promising new technology in the field of solar industry. More and more solar power plants around the world are used in close association with the architectural design, organically blended into the urban environment.

BIPV systems: properties and prospective applications

One of the most promising renewable energy technologies is photovoltaics. Photovoltaics (PV) is a truly elegant means of producing electricity on site, directly from the sun, without concern for energy supply or environmental harm. These solid-state devices simply make electricity out of sunlight, silently with no maintenance, no pollution, and no depletion of materials.

There is a growing consensus that distributed photovoltaic systems that provide electricity at the point of use will be the first to reach widespread commercialization. Chief among these distributed applications are PV power systems for individual buildings.

Interest in the building integration of photovoltaics, where the PV elements actually become an integral part of the building, often serving as the exterior weather skin, is growing worldwide. PV specialists and innovative designers in Europe, Japan, and the U.S. are now exploring creative ways of incorporating solar electricity into their work. A whole new vernacular of Solar Electric Architecture is beginning to emerge.

According to SEIA (Solar Energy Industries Association) report the maximal growth of installations of photo-electric stations in the segment of private home solar power-stations during last few years. On the average total power capacity of solar power station was increasing about 50-60% annually during 2014-2016. Overwhelming majority of houses that use energy of the Sun, generates electricity through stationary roof solar power-stations. Thus, together with market growth, two basic tendencies are clearly noticed:

• Technological factor: increase of efficiency of private solar power-stations, growth of their power capacity, and also creation of systems that will be able to provide functioning of households in fully autonomous mode due to installation of high-capacity storage systems and optimized processes of accumulation/consumption of electric power.
• Aesthetic factor: house owners want photo-electric modules to fit completely naturally  into architectural solutions of their houses, to correspond with main style of a house internal decorations.

Manufacturers, trying to satisfy all requests, offer   package solutions to their consumer; more and more popularity belongs to solar power-stations integrated (built-in) into buildings, or BIPV solutions (from Building Integrated Photovoltaics).

A Building Integrated Photovoltaics (BIPV) system consists of integrating photovoltaics modules into the building envelope, such as the roof or the facade. By simultaneously serving as building envelope material and power generator, BIPV systems can provide savings in materials and electricity costs, reduce use of fossil fuels and emission of ozone depleting gases, and add architectural interest to the building.

BIPV are photo-electric modules, that are intended not only for electricity generation but also are the valuable part of a house as wall material or roofing coverage; they can be used as covers, peaks and other architectural construction elements.  It is thus necessary to distinguish two concepts:

• BAPV (Building Attached PhotoVoltaics) are photo-electric modules that can be considered as additional structures of a house. They are assembled, when erection of a building is already complete, they perform the basic and only duty of electric power generation by transformation of solar radiation. They can be dismantled at any moment, integrity and building reliability will not suffer here. Simplest and most widespread example of BAPV are roof solar power-stations that are assembled over main roof coverage.
• BIPV (Building-Integrated PhotoVoltaics): solar modules are integrated into a building, they perform the same functions of those elements, into which place panels are built-in; BIPV-elements protect a house from moisture, wind, improve thermal and acoustic proofing, simultaneously working as solar panels, namely generating electric power. Their installation is planned on the stage of building design, their dismantling is possible only on condition of substituting them by equivalent building materials.

Such development is connected foremost with development and  enhancement of thin-film flexible solar modules technology. Exactly these modules, in opinion of specialists, will begin to play the main role at BIPV market, because except higher productivity as compared to monocrystal and polycrystal panels thin-film modules have variable degree of transparency, and also can be produced in different colour options. It gives the opportunity to designers to extend traditional architecture designs and harmoniously include hi-tech elements into traditional architectural styles, converting a house into esthetically attractive energy-generating structure.

According to estimations of United States Department of Energy (DOE), in a long-term prospect BIPV systems can provide up to 50% of electric power necessities of the United States. Demand on BIPV systems constantly increases against the background of permanent decline of photo-electric modules prices, and the issue is not only about creation of energy-generating system.

Consumers are interested to get the integral system that will be able to provide maximal energy independence of an object. The market of BIPV already attained some point when it is ready to swift development. But some critically important questions must be decided before such development.

Technical and building standards

New BIPV products, that imitate original appearance of traditional construction materials while performing their energy-generating functions, are considered as single integrated material that must have own standards. From one side, these materials must meet building requirements (in other words structural and mechanical parameters), and from other side they must to meet electrical engineering standards, developed by International Electrotechnical Commission (IEC).

New European standard EN 50583, that determines parameters of BIPV, could be named as large step towards progressive development of the industry.

Fist of all, exact and unambigiuous definitions of BIPV are given in this standard. Integrated photo-electric panels will be considered as BIPV only on following condition: after extraction from building these panels must be substituted by other building materials or constructions to avoid violation of building integrity. The key feature of EN 50583 standard lies exactly herein, it gives clear definitions and outlines BIPV parameters, actually giving them equal rights with traditional building materials.

In addition, functions that can be performed by solar power-stations (photo-electric modules) as part of building construction are clearly defined by the standard:

• Providing of mechanical resistability and structural integrity of a building
• Protecting from aggressive weather factors: snow, rain, hail, wind.
• Providing of power saving: thermal insulation, luminosity level, shading.
• Increase of fire resistance.
• Observance of acoustic isolation norms and standarts.
• Using as a delimiter between internal and external apartments.

Problems of planning and building

Problems of planning of BIPV houses can be divided into two groups:

• Optimization of photo-electric modules location with the purpose to receive maximal amounts of electric power generation. Modern software allows to perform calculations on possible generation amounts to a high precision, and also to obtain maximal amounts due to correct selection of element basis of solar power-station and location of solar modules.
• Development of architectural and construction design of houses with BIPV. Nowadays projects with BIPV systems are not very popular, most architectural offices have a minimum level of experience in building designs with BIPV technologies. However, acceptance of single standard have already considerably simplified designers’ work, they can now operate with well-known concepts and definitions.

Source: avenston