Distributed energy system has the characteristics of high efficiency, environmental protection, economy, reliability and flexibility, and can realize the local utilization and elimination of clean energy, which is of great significance for energy saving and emission reduction. Distributed energy system is directly oriented to the needs of users, combined with the large power grid, can effectively reduce the impact of power load fluctuations on the large power grid, reduce the impact of power outages on users; For border protection, islands and other energy supply difficult areas, multi-energy complementary distributed energy is an important means to solve its energy security problems. As an important component of the future energy system, renewable energy is suitable for utilization through multi-energy complementary distributed supply system, which can overcome the difficulties such as dispersion and instability of renewable energy.
Multi-energy complementary distributed energy system meets the strategic needs of national energy structure adjustment and energy saving and emission reduction, and is also a useful supplement to centralized power supply system. Institute of Engineering Thermal Physics, Chinese Academy of Sciences distributed energy supply and Renewable Energy Laboratory team aiming at multi-energy complementary distributed energy supply, the key technologies such as system efficient integration, solar thermal chemical fuel transformation, hydrogen-rich fuel power generation, energy storage and system regulation have been obtained, and a series of important achievements have been made. Based on the thought of ' grade counterpart, Cascade Utilization ' scientific energy, this paper studies the key technology of efficient integration of solar energy and clean fuel thermochemical complementary system, develops a distributed energy supply system based on medium and low temperature solar thermochemical transformation Coupled chemical heat return, and realizes the efficient and complementary utilization of solar energy and power waste heat. Aiming at the transformation process of solar thermal chemical fuel, a multi-physical field coupling model is constructed, and the optimization analysis of solar thermochemical absorption/reactor structure and operation control strategy is carried out in order to improve the operation performance of solar thermochemical absorption/reactor. Aiming at the efficient utilization of solar fuel (hydrogen-rich fuel), the research on hydrogen-rich fuel power generation technology is carried out, the variable working condition performance of hydrogen-rich fuel engine is studied, and the safety and reliability of solar fuel power generation is improved. Aiming at the temperature faults existing in the process of absorption refrigeration of power exhaust heat driven by dynamic smoke supply technology, a high efficiency waste heat recovery form based on chemical heat return is proposed to realize the transformation of dynamic waste heat to high grade fuel chemical energy, and to reduce the irreversible loss in the process of waste heat recovery. Aiming at the problem of mismatch between solar input and user load, this paper constructs the control model of energy storage and system variable working condition, studies the control method of the system under the condition of solar irradiation intensity and load change, and analyzes the control effect and performance improvement mechanism of chemical energy storage and physical energy storage mode on the variable working condition of the system. The purpose of optimizing the regulation and complementary operation strategy of dual energy storage unit is to improve the operation stability and reliability of integrated solar distributed energy supply system.
The research team carried out experimental research work on the key technologies such as thermochemical transformation, power generation and variable working condition regulation in the solar thermal chemical power generation experimental platform of Langfang R & amp; d Center, and verified the relevant models and control strategies experimentally, all of which achieved the expected goal. The research team proposed the solar thermal chemical distributed energy supply system, integrated solar thermal chemical fuel conversion, chemical heat return, hydrogen-rich power and energy storage and other key processes. The thermal and dynamic waste heat of concentrated solar energy is driven by the integrated solar thermochemical/absorption reactor and fixed bed reactor, respectively, into the chemical energy of high-grade hydrogen-rich fuel, and it is carried out in dense and stable storage, which realizes the efficient utilization of solar energy and power waste heat. Among them, solar net power generation efficiency of more than 20%, the system energy utilization rate of more than 80%. Through the research and development of the key technology of solar thermal chemical distributed energy supply, we can overcome the inherent disadvantages of low density, intermittent and unstable solar energy, break through the limitation of dynamic waste heat recovery temperature fault, large irreversible loss, conquer the transformation of solar thermal chemical fuel, hydrogen-rich power generation and variable working condition, etc., from design to optimization,
From the theory to the application of technical difficulties, the formation of independent intellectual property rights of solar thermal chemical distributed energy supply integration methods and key technologies, access to more than 20 international and national invention patents, and won the China Excellent Patent award, but also published a number of high-quality academic papers. Figure 1.
The structure form of solar thermal chemical fuel conversion and its thermodynamic properties Figure 2.
