Project | Application Practice of Building-Integrated Photovoltaics Adapting to Different Scenarios

Foreword

 

During the "14th Five-Year Plan" period, with the implementation of the national carbon peak and carbon neutrality strategy, governments at all levels have issued a series of policy documents to promote the widespread application of renewable energy in the construction field. This has provided a clear direction for the development of renewable energy building integration technology, and put forward specific technical requirements and implementation paths. Building-integrated photovoltaics (BIPV), a technology that combines photovoltaic components with the building itself, is gradually becoming an important means of promoting green buildings and renewable energy development. Especially with the implementation of relevant mandatory policies, the scale and high proportion of photovoltaic systems in buildings have made significant progress. This article summarizes the promotion and mandatory implementation policies for building photovoltaic applications in Shanghai.

In terms of the effectiveness and impact of building photovoltaic implementation, especially the application of new colored photovoltaic curtain walls, it can not only change the traditional appearance of buildings but also inject new vitality into the city's green development. Taking the application of building-integrated photovoltaic technology as an example, its core lies in closely integrating photovoltaic components with the building, making the photovoltaic system blend into the overall effect of the building or combining the photovoltaic components with building components. This design strategy and application form are not only aesthetically pleasing but also ensure the actual operating performance of the photovoltaic system without affecting the building's function and effect.

OCBC Bank Building (Retrofitting of existing buildings with photovoltaics)

(Combining high-efficiency monocrystalline silicon components with the existing steel frame on the roof of the tower, the system's power generation performance and building appearance are unified under the premise of safety and durability, which is in line with the green building philosophy of transitioning from passive energy saving to active energy generation.)

 

Unlike photovoltaic power plants, which are designed primarily for optimal system performance, distributed photovoltaics integrated with buildings, as building-integrated components and visually visible equipment, must also fully consider a series of key influencing factors caused by differences in application scenarios, such as safety, waterproofing, appearance, and maintenance. In particular, under the premise of ensuring basic elements such as safety, waterproofing, and maintenance, system performance and appearance are the key decision-making priorities for construction units and design units in current engineering practice.

This article will introduce, based on actual engineering applications, the application practices of building-integrated photovoltaics that coordinate performance and appearance requirements in different scenarios, combining current policy mechanisms, technological development, and economic conditions.

/ Key Issues of Building-Integrated Photovoltaic Applications /

 

 

A

Typical Case 1

——New World Cultural Commercial Center Project, Hong Kong

 

Project Overview and Requirements

The project is located in Huangpu District, Shanghai. The plot is bounded by Huaihai Park to the east, Taicang Road to the south, Songshan Road to the west, and a planned green space to the north; the construction land area is 17170.8 square meters, the total construction area is 131612.9 square meters, of which the above-ground construction area is 72802.9 square meters, and the underground construction area is 58810.0 square meters; it includes one office tower with a commercial podium, 26 stories above ground, 120 meters high; 5 street commercial buildings, 3-5 stories above ground, 24 meters high; and a 4-story basement.

This project passed the special review of the implementation plan in August 2022. Based on the relevant implementation requirements, the project's photovoltaic system application needs to simultaneously meet the requirements of the "Shanghai Building Energy Efficiency Regulations" and the "Calculation Standard for Comprehensive Utilization of Renewable Energy in Civil Buildings" (DG/TJ08-2329-2020), with a renewable energy comprehensive utilization requirement of 277341.16 kWh/a.

/ Project Renderings /

 

Problem Analysis and Solutions

Key Difficulties

Irradiation shading from surrounding areas and the project itself—The project is located in the core area of the Huaihai Middle Road business district, on the southeast side of the intersection of Huaihai Middle Road and Songshan Road. High-rise buildings surrounding the site will have a certain shading effect on the irradiation received by the roofs and facades of the buildings within the plot. In addition, the arrangement of the individual buildings within the project plot is relatively compact, resulting in a certain degree of self-shading.

/ Analysis Diagram of Surrounding Project Conditions /

 

Project appearance requirements limit component location and type—The architectural appearance of this project needs to be coordinated with the existing historical buildings to the north. Correspondingly, due to the significant difference in color between high-efficiency photovoltaic components and the main color tone of the project's exterior facade, the feasibility of component arrangement on the facade is limited. In addition, the roofs of the commercial street section are designed with a special "perforated texture" to create an overall effect extending from the facade to the roof. The material and effect cannot be organically combined with conventional crystalline silicon and thin-film components, which also limits the setting of roof photovoltaics in the commercial buildings.

/ Project Roof Renderings /

 

Based on the implementation strategy of "deploying as much as possible," the potential photovoltaic deployment areas for this project are: ① roofs with less irradiation shading and where photovoltaic components can be combined; ② locations with less irradiation shading and minimal impact on the overall building effect.

 

Radiation Conditions of the Planned Deployment Area

The amount of solar photovoltaic components deployed, the appropriate component selection, and the irradiation conditions of the component array have a significant impact on the initial investment cost, building appearance, and operating income of the system. This project has established a refined three-dimensional solar irradiation model to quantitatively analyze the irradiation of the planned deployment area to select the appropriate type of photovoltaic components.

/ Numerical Analysis Model /

/ Component Deployment Area and Selection in Each Area /

 

After comprehensive comparison and demonstration analysis, the component array area and component type for each location are as follows: The roof's projected area is 8911 square meters, the total application area of photovoltaic components is 1792 square meters, and the ratio of component area to roof area is 20.11%.

 

Project BIPV Technology Application Features

Component selection and combination form match the overall building effect—Cadmium telluride thin-film components are used to replace conventional glass in the glass curtain wall of the building crown, achieving integration of components and building components and consistency of facade effect.

/ BIPV Photovoltaic Curtain Wall Application Effect Diagram /

 

Using components suitable for plant growth in combination with roof greening requirements—Buildings 4 and 6 have a 30% roof greening requirement. To ensure compatibility between roof greening and roof photovoltaic deployment, translucent polycrystalline silicon components are used above the roof greening and combined with the roof structure, meeting both the project's roof greening and photovoltaic application requirements.

/ BIPV Translucent Component and Plant Combination Application Effect Diagram /

 

Implementation of capacity maximization strategies under limited layout area restrictions—Due to limited usable roof conditions in this project, it is difficult to meet the renewable energy utilization requirements of the competent authorities; through the matching application of BIPV technology, the photovoltaic capacity that can be combined with the building is increased without affecting the building's function and effect, achieving a perfect fusion of technology and art.

 

Applicable technologies or strategies

This project combines the characteristics and needs of various component application areas. The main component types include three types: conventional monocrystalline silicon photovoltaic components, translucent crystalline silicon components, and translucent thin-film components (including components of different specifications used in skylights, curtain walls, and railings). The total amount of conventional energy substitution calculated according to the current calculation standard is 277388 kWh/a, meeting the comprehensive utilization requirement of 277341.16 kWh/a. At the same time, this project also innovatively applied BIPV to the roof curtain wall and terrace railing areas with better irradiation conditions based on the principle of "using all available space".

The implementation of this project provides an example for the application of large-capacity photovoltaic systems in high-density commercial buildings. Through quantitative analysis, appropriate component selection, and comprehensive consideration of building integration and communication, it can achieve a match and realization of multiple objectives such as building effect, economic benefits, energy saving, and low carbon emissions in the application of building-integrated photovoltaics.

 

 

B

Typical Case 2

——Hang Lung Plaza Urban Renewal Project

 

Project Overview and Requirements

This project is located along Nanjing West Road in Jing'an District, Shanghai. The total land use area is bounded by Nanyang Road to the north, Xikang Road to the west, Nanjing West Road to the south, and Shanxi North Road to the east. This construction is a renovation and expansion project within the existing land area, with the building located in the northwest corner of the land, along Nanyang Road and Xikang Road. In response to the spirit of the document "Implementation Plan for the Economic Construction of Nanjing West Road Backstreets in Jing'an District" issued by the Jing'an District Commerce Commission, to create a personalized and fashionable belt in the Mei Heng Tai backstreets (including Nanyang Road) and a healthy living street on Xikang Road, and to promote the development of the backstreet economy, Shanghai Hang Lung Plaza now plans to demolish the green walls along Xikang Road and Nanyang Road to create a diverse, inclusive, and user-friendly urban public space, and to construct high-quality public places within this plot to improve the public service system.

/ Project Location Map /

/ Project Renderings /

 

In terms of photovoltaic applications in this project, according to the requirements of relevant policy documents such as the "Implementation Plan for Carbon Peak in the Urban and Rural Construction Field of Shanghai" and the "Implementation Opinions on Promoting the Application of Renewable Energy in Newly Built Buildings in Our City," this project needs to meet the 30% roof photovoltaic installation ratio requirement and the renewable energy comprehensive utilization requirement (7392 kWh/a). The thin-film component application area corresponding to this renewable energy comprehensive utilization amount is 64.85 square meters. Through comprehensive analysis, the area of solar photovoltaic installation in this project should not be less than 554.50 square meters, and the average efficiency of the components should not be less than 12%.

Based on the above requirements, this project plans to arrange components on the roofs and tops of Building 3, the coffee pavilion, and the sculpture pavilion, etc., where the irradiation is better; at the same time, it plans to further combine the roof of the existing office building on the south side of this project to install photovoltaic components; among them, the roof and top of Building 3, the coffee pavilion, and the sculpture pavilion have a solar photovoltaic installation area of 429 square meters, and the roof of the existing office building on the south side has a solar photovoltaic installation area of 160 square meters, totaling 589 square meters, meeting the installation area requirement of 554.50 square meters. The roof area of this project is fully covered with 339 gray thin-film components, with an installed capacity of 29.29 kWp; the roof of the existing office building on the south side is covered with 230 standard thin-film components, with an installed capacity of 24.01 kWp; the total installed capacity of the system is 53.30 kWp, and the estimated first-year power generation is 38639 kWh, which can reduce carbon dioxide emissions by 16.23 tons per year.

 

Problem Analysis and Solutions

The implementation of photovoltaics in this project is mainly subject to two major constraints: ① Irradiation blockage from the surrounding area and the project itself; the super-high-rise office building on the southeast side causes significant irradiation blockage to Building 3 and the coffee pavilion of this expansion project; based on the surrounding conditions of the project, the coffee pavilion on the north side is mainly east-facing irradiation; Building 3 on the east side is mainly southwest-facing irradiation; ② Overall effect of the project; the overall facade of the project is a champagne-colored metal finish, which is significantly different from the conventional dark black monocrystalline silicon and thin-film components, which limits the component layout and selection.

/ Surrounding Obstruction Conditions /

Facade Effect

General Component Layout Effect

General Component Style

/ Matching of Component Color and Project Effect /

 

Based on the solution to the above two problems, the project initially proposed a scheme of adding awnings to the partial roof area.

/ Preliminary Proposed Scheme /

 

In the civil engineering design stage, the usable roof area of the project was analyzed in detail. Through quantitative analysis, it was found that the irradiation conditions in the awning area were poor. At the same time, after communicating with the equipment manufacturer in advance, it is also difficult to achieve the same effect as the target profile using integrated components.

/ Detailed Texture Effect of Facade Materials /

/ Overall Irradiation Analysis Diagram of the Planned Layout Area /

 

Based on the above analysis, the irradiation conditions in the awning area are poor, so part of the roof is selected as the component layout area. Correspondingly, since the roof is oval-shaped, to ensure the overall effect of the project from the perspective of the high-rise building on the north side of the project, the project communicated with the planned implementation manufacturer and installation unit in advance during the civil engineering design stage to determine a feasible technical scheme to ensure the final implementation effect. The project finally adopted a layout scheme combining power generation components and irregularly shaped decorative components, ensuring the consistency of the overall project effect.

/ Roof Component Layout Diagram /

 

Applicable technologies or strategies

The typical requirement of this project is to ensure the overall effect of the project, so the selection of equipment, reserved conditions, etc., are all key considerations of the project. Through "advance consultation with the construction and implementation unit" and "deepening node design," the predetermined goals were achieved. From this case, it can be seen that for special projects, advance docking between design and construction is an effective measure to ensure the final completion effect.

 

Conclusions and Outlook

 

BIPV is not only a technological innovation but also an imagination of future urban lifestyles. With the maturity of technology and the reduction of costs, BIPV is expected to become standard equipment for more buildings, bringing cleaner and more sustainable energy solutions to cities.

The implementation of building-integrated photovoltaic projects requires not only advanced photovoltaic technology but also close cooperation between architects, engineers, and owners. When designing building schemes, designers should consider the layout of the photovoltaic system to ensure that it meets both architectural aesthetics and optimal energy output. At the same time, engineering and technical personnel need to ensure the stability and safety of the photovoltaic system to guarantee the reliability of the building during use.

In addition, the promotion of BIPV faces several challenges. Ensuring the durability and safety of photovoltaic components, integrating them aesthetically with building design, and addressing installation and maintenance issues are all matters requiring our collective consideration. Simultaneously, policy support and market acceptance are key factors driving the development of building-integrated photovoltaics.

 

 

Project Information

 

Project Name | New World Cultural Commercial Center Project, Hong Kong

Developer | New Generation Huai Zhong Commercial Development (Shanghai) Co., Ltd.

Construction Location |  Huangpu District, Shanghai

Land Area |  17170.8 square meters

Total Construction Area |  131612.9 square meters (72802.9 square meters above ground, 58810 square meters underground)

Building Height/Floors |  120 meters/26 floors (1 office tower); 24 meters/3-5 floors (5 ancillary buildings); 4 underground floors

Specialized Consulting and Design Unit |  Shanghai Science and Technology Development Branch of Huajian Group, Huajian Group East China Architectural Design and Research Institute Co., Ltd.

 

Project Name | Hang Lung Plaza Urban Renewal Project

Developer |  Shanghai Hengbang Real Estate Development Co., Ltd.

Construction Location |  Jing'an District, Shanghai

Land Area |  31168 square meters

Construction Area | 10197.35 square meters (3713.35 square meters above ground, 6484 square meters underground)

Building Height/Floors |  18.2 meters/3 floors above ground, 1 floor underground

Specialized Consulting and Design Unit |  Shanghai Science and Technology Development Branch of Huajian Group, Huajian Group East China Architectural Design and Research Institute Co., Ltd.