In recent years, my country has vigorously promoted the integration of solar energy with buildings, and solar thermal technology has been widely applied in civil, public, industrial, and agricultural buildings. Statistics show that by the end of 2016, the penetration rate of solar water heaters in my country had reached 60%, with an industry installed base of approximately 440 million square meters, accounting for 75% of the world's solar water heater installations. However, many users are not accepting the integrated solar energy and building-integrated technology projects that have been implemented across various regions.

The Integration of Solar Energy with Building Design Cannot Be Ignored

　　Recently, the "2015-2016 World Solar Thermal Development Report" (hereinafter referred to as the "Report"), a joint research result of the International Copper Association, the IMSIA International Metal Solar Energy Industry Alliance, and other organizations, was officially released. The report reveals several issues: In a Ningbo residential community, residents jointly signed a petition demanding the removal of solar water heaters provided by the developer. In a Beijing community, individual solar thermal systems became almost unusable two years after residents moved in. In a Hangzhou community, the "connected" solar water heaters provided as a gift became useless. In an Anhui community, solar energy, presented as a "green benefit" by the developer, was collectively rejected by over 200 households… Meanwhile, the actual energy-saving effect of solar thermal systems often falls far short of design requirements. Surveys show that many projects, designed for 50%-60% solar thermal utilization, only achieve an actual energy-saving effect of around 30%.

　　“Many projects, despite achieving simultaneous design, construction, and operation, still yield poor results due to a variety of reasons,” said Huang Junpeng, Secretary-General of the IMSIA International Metal Solar Energy Industry Alliance. “Developers and property management companies only activate solar systems when the occupancy rate of a residential area exceeds 80%, and solar water heating systems are most vulnerable to prolonged periods of unused sunlight. Often, the system breaks down or ages before it is even officially put into use. Furthermore, the low barriers to entry in the solar thermal industry and the practice of awarding contracts to low-price bids also affect the quality of solar systems.”

　　Huang Junpeng also pointed out that planning and design significantly impact the application of solar water heating systems. Inadequate system design, such as insufficient collector area, mismatched tank volume, or unreasonable parameter design, can lead to problems in the later operation of the system. He believes that the type of solar water heating system, the selection and installation location of the collector area, the selection and installation location of the tank, as well as the expansion tank, piping, and auxiliary energy sources, should be considered during the project design phase, and reasonable basic system parameters and solar energy guarantee rates should be determined. "However, in actual engineering projects, most architectural designers delegate solar energy design to manufacturers rather than designing it themselves." In reality, it's not uncommon for solar energy equipment to be purchased only after the building design is completed and construction begins.

　　Currently, my country has the world's largest solar thermal area, but in terms of per capita ownership, it has only just entered the top ten globally, indicating enormous future market potential. According to the "13th Five-Year Plan for Solar Energy Development" released by the National Energy Administration, by the end of 2020, my country's solar thermal utilization area will reach 800 million square meters, meaning the installed area of solar thermal systems will double in the next four years. Although more than 20 provinces and cities across the country have issued mandatory or incentive policies for solar building applications, in cities, the area available for solar energy utilization, like building land, is a scarce resource. The available solar thermal collection area is very limited, and each building only has limited balcony and roof areas available. How can we fully utilize this scarce resource and maximize the role of solar energy in promoting building energy conservation? How can we move from policy-driven development to a genuine focus on the actual energy-saving effects of solar energy, bringing consumers a more comfortable and convenient domestic hot water experience? The integration of solar energy and buildings requires collaboration and integration between the solar energy industry and the construction sector.

　　Li Liqun, Assistant General Manager of the Design Management Department of Shanghai Sanxiang (Group) Co., Ltd., pointed out that currently, solar energy manufacturers and the entire solar energy-centric industry chain are overly focused on their own products, failing to integrate technological and system upgrades of solar energy into overall building energy conservation. “Specifically, for each project, how do we select a solar energy system? Should we choose centralized collection and individual metering, or distributed systems? These questions need to be discussed in the early stages of building design. Simultaneously, the layout of the solar system must be studied during the planning and design phase, and the solar sunshine hours on the building facade must be analyzed. Then, we can work backward to calculate the installation method and layout of the solar collectors. Since the lifespan of a building is 70 years, while the lifespan of solar energy products is about 20 years, the design phase must also reserve space for the inspection and maintenance of the solar system.”

　　Dr. Han Dongchen of the School of Architecture at Tsinghua University believes that integrating solar energy with buildings is a complex process from design to manufacturing, then to construction, and finally, the integration of manufacturing and construction. Designers must not only understand architectural design but also solar energy products and systems, and must comprehensively consider installation, construction, and subsequent operation and maintenance to achieve true integration of solar energy and buildings. In the design process, to verify the reliability of the design, system simulations of the solar energy system and building energy consumption should be conducted, and the design scheme should be revised based on the data. Furthermore, Huang Junpeng believes that although there are already many standards for integrating solar energy into buildings, there are still gaps in standards that truly provide practical guidance and reference for developers and designers, and these standards urgently need to be developed and improved.