1. Solar energy is an inexhaustible clean energy source in the field of solar energy building application in China at present, and it is one of the most promising energy sources that human beings can expect after 2 1 century. The application of solar energy in buildings is a practical field with development potential at present. Modern buildings should have a series of functions such as heating, air conditioning, hot water supply, power supply (including lighting and electrical appliances) to meet the comfort requirements and use needs of residents. The overall goal of scientific research, technology, product development and engineering application in the field of solar energy building application is to use solar energy instead of conventional energy to provide the above functional requirements of buildings. With the continuous improvement and progress of solar energy technology in the world, strictly speaking, solar buildings should be able to use solar energy to meet most of the energy supply needed by occupants' comfort and use functions, that is, to realize the comprehensive utilization of solar energy in buildings. At present, solar energy can only be partially used in buildings in China, and there are still many problems to be solved in rationality and practicability, which is far from the advanced level in the world, especially in practical engineering application. At present, in the field of solar building application in China, the most mature technology, the most extensive application and the fastest industrialization development are domestic solar water heaters, followed by passive heating solar houses; Demonstration projects of solar hot water system, solar energy heating, air conditioning, solar photovoltaic grid-connected technology and building integration have been completed, but the level of large-scale application is very low. Generally speaking, the combination of solar energy collection system and building, the comprehensive utilization of solar energy hot water, heating and air conditioning in buildings, and the comprehensive utilization of solar energy photothermal and photoelectric technologies are the main application fields and technical development directions of solar energy buildings in China at present.
2. The development goal of solar energy building application field is to catch up with the international advanced level, build all kinds of solar energy comprehensive utilization demonstration buildings, popularize them on the basis of setting up typical models, and promote the sustainable development of national economy, which is the overall development goal of solar energy building application field in China in the future. Therefore, it should be implemented step by step according to the comprehensive influencing factors such as technological progress and economic level: first, the architectural integration of solar water heaters (systems) with the most mature technology and the most extensive engineering application should be completed, and then the solar photothermal utilization-heating and air conditioning, as well as the development and engineering application of photothermal and photoelectric comprehensive utilization technologies for power supply, heating and air conditioning; First, develop individual technologies and related products of building integration, then build demonstration projects, and finally realize the popularization of solar energy comprehensive utilization buildings.
Second, the history and present situation of solar energy building application in China.
1, solar water heater (system) The development and utilization of solar water heaters in China began at 1958. The first solar water heater was developed by Beijing Architectural Design Institute and used in the public bathroom of Beijing Paradise River Farm, but it developed slowly until the global energy crisis in the late 1970s, which made renewable energy represented by solar energy become a substitute for fossil energy such as coal and oil. Over the years, thanks to the policy support given by the China Municipal Government for the utilization of new energy and the diligent efforts of scientific and technological workers, the solar hot water industry, as a new industry, has developed rapidly by insisting on the transformation of scientific research achievements into productive forces and the combination of Industry-University-Research. Beijing Tsinghua Sunshine Energy Development Co., Ltd., one of the "Top Enterprises of China's Science and Technology (Solar Energy) Independent Innovation 10" selected by this research activity, is a typical representative in this respect. The company won the "second prize of national scientific and technological progress", invented the patented AL-N-AL solar selective coating process with independent intellectual property rights, and initiated and developed the vacuum tube solar collector industry in China. Therefore, at the world solar energy congress in 2005,
The solar water heater industry in China has developed rapidly since the end of 1990s, with the output increasing from 3.5 million m2/ year in 1998 to150,000 m2/ year in 2005 and the total installed capacity of water heaters increasing from 1998 to 75 million m2/ year in 2005. The cost of solar hot water is equal to or lower than that of hot water heated by electricity or gas/natural gas. All these have laid a foundation for the further development of solar water heaters/systems in China.
However, for a long time, solar water heaters were purchased and installed by users only after houses were built. With the increasing popularity of solar water heaters in cities, a series of problems and contradictions brought by this mode of use have gradually emerged, especially the impact and destruction on the appearance of buildings and the related use functions of houses, which directly led to the introduction of management regulations prohibiting the installation of solar water heaters in some cities, communities and units, which seriously restricted the further development of solar water heaters. Therefore, solar water heaters/systems must be integrated with buildings, which has formed awareness in solar energy utilization academia, industry and construction industry, and received strong support from government agencies at all levels, such as the National Development and Reform Commission, the Ministry of Construction and provincial and municipal construction departments, and made substantial progress during the Tenth Five-Year Plan period.
During the Tenth Five-Year Plan period, the national key scientific and technological projects and related international cooperation projects have achieved a number of significant results. Based on the technical progress of the original products, the adaptability of the existing solar collectors to building integration is improved through the redesign of the system, water tank, support and control components, and the quality control of product safety, reliability, stability and durability. Successfully developed solar collectors for building components, such as Xinyuan hot plate; Model projects have been built in various places, which have set a good example for the implementation of architectural integration and accumulated experience, such as Pearl Hotel in West Yunnan Lijiang, Kunming Hongta Jindianyuan Community, Hongzhuyuan Community in Mengzi County, Yunnan Province, Emerald Garden Community in Nanning, and Green Park Community in Long Island, Hangzhou, etc. The "Top Enterprises of Independent Innovation in Building Technology (Solar Energy) 10 in China" selected by this research activity: Shandong Huang Ming Solar Energy Co., Ltd. and Kunming Xinyuan Sunshine Technology Co., Ltd. are the product suppliers and project design and construction partners of these demonstration projects.
The National Tenth Five-Year Scientific and Technological Key Project "Integration and Demonstration of Solar Heating and Refrigeration Technology" has also completed the development of design software for building integrated solar water heating system and the compilation of standard atlas. The function orientation of the design software is to serve the engineering design, including: meteorological database, solar collector/water heater performance parameter database, construction practice graphic database combined with buildings and four optimization design calculation function blocks. It has the functions of load calculation, system design, equipment selection and economic benefit analysis, which will effectively solve the problem that the current system design lacks basic parameters and basis.
During the Tenth Five-Year Plan period, funded by the United Nations Development Programme (UNDP) and authorized by the General Administration of Quality Supervision, Inspection and Quarantine and the National Certification and Accreditation Administration, two national quality supervision and inspection centers for solar water heaters were established in China, located in China Institute of Building Science (Beijing) and Hubei Institute of Product Quality Supervision and Inspection (Wuhan) respectively. Since their establishment, the two centers have completed three years of national product quality supervision and spot checks, as well as major inspection tasks such as product certification and product quality arbitration, which have played an important role in improving the product quality of solar collectors/water heaters and promoting the technical progress of the industry; The product performance parameters obtained through centralized inspection can also be used as an important basis for system design. Supported by the same UNF project, the Technical Specification for the Application of Solar Hot Water System in Civil Buildings, funded by the United Nations Foundation (UNF) and approved by the Standards and Quotas Department of the Ministry of Construction, was officially implemented on June 5438+ 10, 2006, and the Technical Manual of Solar Hot Water System in Civil Buildings has also been published. In addition, some standard design atlases have been compiled and distributed. The completion and application of these standards, specifications, manuals and atlas will greatly improve the design and construction level of building integrated solar hot water system in China, and make the whole process of building integrated solar hot water system have rules to follow.
In terms of policies and regulations, with the formal implementation of the Renewable Energy Law 5438+ 10 in June 2006, various localities and departments have successively formulated corresponding implementation rules, among which the provisions on the utilization of solar hot water have made great progress compared with the past. Some cities in some areas have put forward the provisions that solar hot water systems must be installed in new buildings below a certain height in the form of local regulations, such as Dalian and Shenzhen.
However, the integrated development of solar hot water system buildings in various places is unbalanced, and there are some misunderstandings. Most architectural design institutes and real estate developers don't pay enough attention to building integrated solar water heating system, and some solar water heater manufacturers still stay in concept and don't invest substantial efforts. There are many reasons for this. One of the reasons is that the competition in China solar water heater market is fierce, but the sales are still strong; Building integration puts forward higher requirements for the functional quality of solar collectors. It is difficult to invest capital and technology in product transformation or new product development, and there will be a lack of motivation under the current market conditions. The second reason is that professional architectural design institute, as the main body of architectural design, basically did not intervene in the design of solar hot water system in the past, was unfamiliar with solar heat collection system and lacked necessary basic design parameters. This makes designers feel countless, leading to a lack of enthusiasm for unfounded design.
The third reason is that the initial investment of building integrated solar hot water system needs to be borne by real estate developers. If the increase in development costs can not drive housing sales at the same time, it will affect the enthusiasm of developers.
2. Solar heating and air conditioning According to international terminology, solar heating methods can be divided into two categories: active and passive. Active type is a forced circulation solar energy heating system consisting of solar collectors, pipes, fans or pumps, terminal heat dissipation equipment and heat storage devices. Passive type is to collect, maintain, store and distribute solar heat energy in winter through reasonable arrangement of building orientation and surrounding environment, clever treatment of internal space and external modeling, and proper selection of building materials and structures, so as to solve the heating problem of buildings. The house built by passive solar heating principle is called passive heating solar house. The active solar heating system is mainly completed by HVAC engineers, and the passive heating solar house is mainly completed by architects.
Because the active solar heating system is complex and has many devices, the initial investment and regular maintenance costs are higher than those of passive solar heating. China is a developing country with relatively backward economic development. Starting from the national conditions, the policy adopted in the past was to give priority to the development of passive solar heating. 1977 the first passive heating solar house in China was built in Minqin county, Gansu province. After more than 20 years' efforts, China has formed a theory, design, construction, testing and evaluation method with China characteristics through the national key scientific and technological projects of the Sixth Five-Year Plan, the Seventh Five-Year Plan and the Eighth Five-Year Plan, on the basis of introducing, digesting and absorbing the world's solar building technology. Restricted by the economic level, the development of active solar energy heating system in China has been relatively slow, and only a few experiments and demonstration projects have been completed in recent years, such as the solar floor radiant heating project of Lhasa Railway Station and the office building of Tsinghua Sunshine Energy Company. The popularity of this solar energy heating system lies not in the technology of heat collection and heating itself, but in the high investment cost and the surplus of hot water in spring, summer and autumn, which should be solved by seasonal energy storage technology and comprehensive utilization throughout the year.
Because the application demand of air conditioning is in good consistency with the supply of solar energy, that is, the hotter the weather, the more air conditioning is needed and the greater the corresponding solar radiation, so solar air conditioning is the earliest research field of solar energy application in China. At the end of 1970s, the research on the application of solar energy in buildings in China just started, and many domestic units began to engage in the research and development of solar refrigeration and air conditioning systems. Among them, the experimental device of solar ammonia absorption or lithium bromide absorption refrigeration successfully developed by Huazhong University of Science and Technology, Shanghai Jiaotong University and Air Conditioning Institute of China Academy of Building Research has been put into trial operation, which provides a useful reference for the solar air conditioning system to enter the engineering practice in the later period.
During the Ninth Five-Year Plan period, two solar air conditioning demonstration projects were completed: the solar air conditioning hot water system designed by Guangzhou Energy Research Institute of Chinese Academy of Sciences for China Construction Bank Building in Jiangmen City, Guangdong Province, and the solar energy absorption air conditioning heating comprehensive demonstration system built by Beijing Solar Research Institute in Rushan City, Shandong Province; In recent years, the office building of Beijing Solar Energy Research Institute, Tianjin Haitai Software Park and other solar air conditioning demonstration projects have been built one after another. The focused solar collector developed by Yuanda Air Conditioning Co., Ltd., which can provide 140℃ high-temperature hot water, is a key product suitable for solar air conditioning system, and several pilot projects have been built at home and abroad. In addition, the heat pump air conditioning technology that comprehensively utilizes solar energy and geothermal energy has always been a hot spot in scientific research and development. The main problems of solar air conditioning technology in engineering application are high investment and large area of solar collector. The popularization of this technology depends on the development of medium and high temperature solar collectors and the reduction of costs.
3. Photovoltaic technology Solar cells in solar buildings are combined with building envelope or building materials. Photovoltaic modules are installed on roofs and walls in the form of photovoltaic glass, or as a part of building envelope. In recent years, solar buildings that use photovoltaic grid-connected power generation technology to provide energy consumption for residential buildings have become the focus of solar energy utilization in the world A considerable number of such solar buildings have been built and put into use in developed countries, but they are in the initial stage in China. Although China's solar photovoltaic technology has reached a high level of development and industrial scale after decades of efforts and the bright photovoltaic power generation project implemented by the state in recent years to solve the power supply problem in rural areas, due to the constraints of the country's economic strength, there is still a big gap between China and developed countries in terms of integration with buildings and engineering application.
At present, the annual production capacity of solar photovoltaic modules in China is 150MW/ year, and the annual output is1100mw/year. By the end of 2004, 60,000 kilowatts of solar photovoltaic cells had been installed in China, among which the demonstration project of photovoltaic grid-connected power generation was Shenzhen International Garden and Flower Expo Park 1MW project. Because the initial investment of this kind of building is very expensive, it will take a long time to popularize it in China.