多能源热互补分布式能源系统的节能率评价方法

多能源互补是分布式能源系统的重要发展方向,相比于化石能源驱动的分布式能源系统,其节能特性的评价方法研究尚有不足。针对多能源热互补分布式能源系统提出节能率的计算方法,将系统输入的低品位非化石能源按其做功能力统一折合成燃料,与输出相同产品的常规分产系统进行比较得到节能率。通过典型太阳能与燃料互补的分布式能源系统比较分析了3种节能率计算方法下,可再生能源占比、不同形式能量输出比、热/热化学输入热的温度等参数对系统节能性的影响规律,并以具体的热电联产案例验证了文中节能率计算方法的适用性。结果表明,所提出的节能率计算方法能够更为合理地评价含有非化石能源的多能互补系统节能特性,获得了节能率随可再生能源占比增大而增大,随热互补太阳能集热温度升高而降低,随热化学互补太阳能集热温度升高而先上升后下降的规律,反映了根据能的品位合理利用非化石能源和提高多能互补技术先进性能够改善系统的节能性能。

Evaluation Method for Energy Saving Ratio of Distributed Energy System with Multi-energy Thermal Complementarity

Multi-energy complementarity is an important development direction of distributed energy system. Compared with fossil energy driven distributed energy system, the evaluation method of energy saving characteristics is still inadequate. The input non-fossil energy of low grade is converted into fuel according to the work ability, and the energy saving ratio is then obtained by comparing with the conventional sub-production system which has the same products. The effect of parameters such as the proportion of renewable energy, different energy output ratios and inputting heat temperature of thermal or thermochemical complementarity on the energy saving characteristics of the system is analyzed through a typical solar energy and fuel complementary distributed energy system, and a specific cogeneration case is studied to verify the applicability of the proposed calculation method of energy saving ratio. The results show that the evaluation method of energy saving ratio proposed can more reasonably evaluate the energy saving characteristics of multi-energy complementary system with non-fossil energy. The energy saving ratio increases with the increase of the renewable energy proportion and decreases with the increase of the solar collecting temperature of thermal complementarity. With the increase of the solar collecting temperature of thermochemical complementarity, the energy saving ratio rises first and then declines. The results reflect that rational use of non-fossil energy according to the energy grade and the performance improvement of multi-energy complementary technologies can improve the energy saving characteristics of the system.