Polaris solar PV net news: into the 21st century in more than 10 years, energy shortage and environmental deterioration have become increasingly prominent. Developing renewable energy instead of conventional energy is the only way to solve the above problems. Solar energy because of its huge reserves, the advantages of using a clean, wide distribution, and in recent years has become the most popular renewable energy. PV industry in all major countries of the world will be as one of the focus of the study, and have implemented their plans. United States, California, driving millions of building, the EU White Paper on renewable energies plan, Germany’s solar-powered Internet subsidy program, and so on.
In China, the benefits from national policy support, the industrial application of solar energy photovoltaic industry also developed rapidly. Respectively by the energy Bureau of national development and Reform Commission and the Ministry of housing and urban-rural development take the lead in the Golden Sun demonstration project and solar rooftop project, as well as distributed generation scheme introduced by the end of 2012, there are quotas for new energy development goals have been written “Twelve-Five” program.
In the future will focus on the development of BIPV
At present, the scale of China’s solar industry has ranked first in the world. It should be noted that economically active areas of the eastern coast economic zone after urbanization energy shortages, accumulation of buildings, land, is not conducive to the development of large terrestrial photovoltaic power plant, but it is very suitable for the development of BIPV. Although individual BIPV projects, though small in size, but drop by drop the sea and local supplement to the power shortages, and solves the problems of long-distance transmission of PV loss.
After years PV application development, whether it be development-oriented, or real policy effect, starting from this year, has gradually changed from a large ground station applications transition to a distributed generation model, based on the architecture of distributed generation into the golden decade of the development cycle.
BIPV power model, due to its “low cost, low power transmission cost, integrated low installation cost” advantages and features, become focus of China’s solar energy development.
Building materials after years PV product industry, is now mature and able to meet the current market demand.
In price aspects, building materials type PV products (as PV curtain wall with film component, and PV w), and other similar upscale material compared to has has obviously of can compared sex and feasibility, and in size, and color, and strength, and power security, and building aesthetics, aspects also can meet building application of special requirements, products of light degrees, and color, and structure are can according to building requirements for custom of production.
Additional type of industrial plant (BAPV) applications because of the low as possible of the building, will be phased out.
Large steel structure of industrial factory building roof color rather than a concrete structure, which makes the roof load and service life are very risky. As we all know, color steel roofing life span of up to 15 years (starting from the photovoltaic project has less than 15 years), and photovoltaic power generation agreements signed is 25, which does not match.
Residential roof for concrete structures, which can avoid this problem. Rooftop PV Application principles of industrial enterprises is the spontaneous use of energy consumption and power. Enter “Twelve-Five” in the future, coastal developed area industrial structure transformation determines that such enterprises will be less and less, nor the State encourages the development of energy-intensive industrial companies, and due to roof the owners of industry stability, load restrictions and other restrictions, industrial roofing resource shortages already emergent, which resulted in industrial enterprises in future large-scale application of PV on the roof space is decreasing.
Residential roofs applications can effectively avoid the industrial application of a number of key factors, project feasibility analysis and business models, and many other more viable. Business owners signed a power purchase agreement with the roof up to 25 years, while residential property clear and stable, there are no PV plant operation of this aspect of the project owners, change, renewal and other uncertain risks, so their business model risk, tariff income stability, is actively exploring and promoting photovoltaic demonstration of good project type.
Commercial building, with its higher power generation efficiency, large capacity, low loss, high retention time is long, high demonstration effect, will be the key pilot provinces.
Due to different facing greater influence on electricity, so the roof project is the most efficient BIPV locations, and commercial building is noted for its large roof but mostly unused roof. Commercial building roofing such as Yiwu small commodity market area of more than thousand square, installed more than 1MWp, is a big Mac in BIPV projects.
In addition, big big business generally rely on the power of lighting, and hours more for the day and no intermission, without electrical storage devices, reduce investment, and without long distance transmission, in-place using low loss.
In addition, commercial buildings are generally permanent building, General design working life for 50 years, shorter development time, duration of the actual power station can equal or exceed equipment life of PV and high population concentration, more suitable for the introduction of new products and new technologies.
Government also will take must of forced and encourages measures vigorously advance commercial building of demonstration work, on developers of forced measures including large commercial building needs reached building green certification design and operations II star or Samsung requirements, on developers of award measures including in obtained National Green built subsidies of while, local Government also can supporting Award Fund, and in land transfer, and project approval, and tax Shang gives must of award initiatives. Departments may establish their development goals, encourage departments to actively coordinate linkages between developers and power plant investment operators to promote commercial development of BIPV.
Attention in design of BIPV
Solar module form and specifications needed to diversify.
Kit form including monocrystalline silicon, polycrystalline silicon cells, micro-crystalline thin film solar cells, amorphous thin film batteries and soft membrane cells, as well as derivative products such as solar photovoltaic tiles. Crystalline silicon solar module can according to the architectural form of typesetting a variety of standard sizes, daylighting and aesthetics can also request the production of different light transmission plates. Thin film solar module now there are several manufacturers of different sizes to be adjusted, and manufacturers can be semi-finished products of any size cutting, these are designed to meet the demands of architectural design. But also develops directly into traditional building style of PV tiles, soft film batteries.
With so many types of batteries, in the design choice is essential.
First of all, is to meet the architectural requirements and PV photovoltaic modules that are used in the ground, just passed the IEC61215 test to meet the anti-130km/h (2,400Pa) 23m/s 25mm diameter hail impact resistance and wind pressure requirements. BIPV photovoltaic modules are not only needed to meet the performance requirements for PV modules itself, at the same time to meet the four experimental requirements of curtain walls (wind resistance properties, in-plane deformation, air-tightness and water-tightness) and safety performance requirements of the building, thus the need for higher mechanical properties and with different structures.
Second, select crystal silicon battery Shi, if part location has block, will considered crystal silicon component of hot spot problem, then of bypass diode no works, although shadow of degree no reached diode of anti-Wizard pass voltage, then produced of hot spot effect although not enough to on component caused damage, but long-term in this state of battery pieces will was obviously of damaged, so in State surface too sun angle poor and has shadow of location as considered film battery pieces. Crystalline silicon solar modules and thin-film solar module voltage gap is large, and voltage of components from different manufacturers have different needs depending on the actual configuration of electrical parts.
Junction boxes requires miniaturization and diversification
Junction box for batteries and other equipment necessary to connect the device, and when combined with curtain walls, building requirements for it is invisible, so the design of the junction box on the progressive miniaturization and hidden inside the plate seams or decoration.
Traditional junction box
Junction box on the wall with a small
Short cable connectors, combination plates required a much smaller group of
Photovoltaic power generation efficiency improvement even 0.1% researchers spend a lot of energy, time and money to get, but in cable transmission losses are almost 1%, how to reduce the loss of cable and other equipment is important to note that in designing BIPV.
Curtain wall application must take into account indoor and outdoor beauty, lines must be done inside and outside is not exposed. Grouping plates by series-parallel combination of increased solar panels, reduce the impact of individual plate damage the efficiency of the system as a whole.
Controllers and inverters to be combined inverter needs compact, modular.
Now many controllers and inverters are designed together, so that the equipment maintenance, reduce the odds. Addition due to individual plate damaged will led to whole series power by effects, loss more capacity, sometimes also will should for Sunshine conditions changes led to too much inverse variable device load participation work led to efficiency declined, factors, restricted has large inverse variable device of efficiency of improve, so now needs considered inverse variable device of module of design, now has has manufacturers used smart of dormant technology, makes inverse variable device of Supreme efficiency improve to 98.6%, European efficiency improve to 97.6%, and used low voltage 50~ A 500kW free combination, and support hot-swappable, you can install with no downtime maintenance, and improving network communication function and easy to monitor the operation of the system as a whole, it is a better direction of BIPV.
In addition, micro-inverters for each component separately, and more conducive to improving the efficiency of the whole system, especially the many kinds of plates and use a more complex is the better choice, but the current high cost of such programmes, must be considered.
Reducing the use of batteries. PV modules itself only generating function, are not capable of storing function. Grid-connected and is a component of the electricity directly to the national grid, do not need energy storage through backflow protection devices can be done safe and seamless to use. Off-grid is used alone, in the case of light is not strong or no sunlight at night, you also need power to rely on a battery provides power. Electricity from the PV module to charge the battery during the day, for night use, this investment will be higher costs for configuring storage devices.
Photovoltaic battery, mainstream is maintenance-free lead-acid batteries, cheap and low cost advantages, easy maintenance, the disadvantage is lower capacity, short life. There is also a lithium-ion battery, the advantage of easy maintenance, high capacity, the disadvantage is that because just being used in the photovoltaic industry, cost is very high, yet no substitute for lead-acid batteries. There is an energy storage device, is super capacitor, the advantage of volume can be very high, but the disadvantage is still in the development stage and immature. Off-grid systems due to the high investment and maintenance of storage link is not the direction for future development, so we minimize battery use.
Profiles easy to repair and cable concealment
BIPV photovoltaic modules installed than the installation more difficult, many common components. BIPV installation height is higher, generally smaller installation space. Taking into account the ease of installation, photovoltaic modules and the structure can be made of modular structure, easy to install and improve the accuracy of curtain wall installation. Photovoltaic curtain wall unit can be used in place of bright frame curtain wall with hidden frame curtain wall. Authors have also been developed for framing and bright frame curtain wall used lateral drainage hidden system solved the problem of solar module wiring. Interior side open the hidden system is designed, and solved the problem of line detection and repair for PV systems, BIPV photovoltaic modules in the application connector are all hidden in the wall structure. Need to further improve our future design requirements in this regard.
Easy to repair and hide the BIPV system façade cladding system
BIPV future research directions
Continue to improve efficiency, improved low light performance of the product.
BIPV systems commonly used crystalline silicon solar cell conversion efficiency (polysilicon 13~16.5%; mono 16~18.5%) also needs to be strengthened. BIPV systems using thin film solar cell (Copper Indium selenium and Copper-Indium-Gallium-selenium 11~13%; 8~11% of cadmium telluride; gallium arsenide and polymer 10~14%) due to the low light performance, efficiency is good. Application of curtain wall needed solar module with a high temperature coefficient and low light, infrared and ultraviolet light with good absorption and transformation of photovoltaic plates used on the curtain wall facade, save the use of traditional panels on walls and low reflection rate, no light pollution, with good economic and social benefits. Economic indicators for future research and development the main control for building integrated photovoltaics price 2015 fell to 14/w (now integrated estimates costs about RMB 16/w) 6. System power generation efficiency of more than 80%.
Continue to improve with the construction of combined degrees
Building walls is a synthesis of technology, art and function, so architects on the material color and size will have higher requirements, so we need to further enhance the combined PV and architecture, develop more building materials III, offers beautiful and practical photovoltaic products, further improve the taste.
Application of DC, integrated
Current photovoltaic power generation is DC, so try to consider the practical application of DC load, reduce costs and losses. Integration of photovoltaic and thermal insulation materials electrochromic integration, photovoltaic, photovoltaic and solar thermal integration, PV-LED integration also later applications.
Module specifications and color variety, and raise the level of industrialization and modular production: traditional crystalline silicon cells Although stability is good, but expensive, and the battery itself is not transparent and lighting need to adjust cell spacing to achieve, following extensive research and development to improve the industrialization rate, so you can reduce costs, but also research and development of new packaging methods and materials color-rich crystalline silicon solar module. (Author: Zhejiang zhongnan construction Group Co Ltd)
Original title: talking about BIPV application and design requirements