供冷系统能耗评价模型及应用

随着人民生活水平提高，供冷系统日益普及。受全球气候变暖和能源资源短缺问题影响，供冷系统能耗控制日益受到广泛关注。为科学表征供冷系统能源消耗状况，将供冷系统划分为六个子系统，从总能系统层次上给出了适合于各类供冷系统的广义化的能耗评价一般模型。在此基础之上，结合单耗分析方法，提出了供冷系统能耗的定量计算方法。采用了热力学第一定律、热力学第二定律分析，对供冷过程的热力学本质、冷量?、供冷能力等方面展开研究，系统阐述了供冷系统的理论节能极限及理论最低能耗，并立足总能系统对供冷过程的理论极限－可逆供冷作出了说明。在北京市目前设计标准下，供冷系统理论最低燃料单耗为0.82kg/GJ，当前供冷系统能耗水平（25.27 kg/GJ）与之相比，节能潜力甚大。为验证所构建的供冷系统能耗评价一般化模型，结合北京市通州区供冷系统的实施方案，对分散电制冷、集中电制冷、分散热制冷、集中热制冷四个基本类型的供冷模式进行了实例计算分析，并与四种模式的?分析计算结果进行了比较，结果显示：所提能耗模型与?分析结果一致，电制冷燃料单耗低于热制冷，分散制冷燃料单耗低于集中制冷，集中热制冷能耗较高，应慎重发展。所提出的能耗分析评估模型为各种类型供冷系统的一般化对比评估提供了理论分析方法，同时可为城市供冷系统的规划设计提供参考。

Energy Consumption Evaluation Method and Application of Cooling System

Affected by global warming and shortage of energy resources, cooling system is increasingly popular, and its energy consumption control is widely concerned. In order to represent the energy consumption of the cooling system scientifically, the cooling system was divided into six subsystems, and a generalized energy consumption evaluation model for different types of cooling systems was proposed from the aspect of total energy system. On this basis, combined with the theory of single consumption analysis, a quantitative cal-culation method of energy consumption of cooling system was proposed. By analyzing the first and the second laws of thermodynamics, thermodynamic essence, cooling exergy and cooling ability in the process of cooling was discussed, and illustrated the theory minimum of energy saving of cooling system and fuel consumption, and theory limit of cooling system and reversible cooling were expounded based on the gen-eral energy system. Under the current design standard of Beijing, the theoretical minimum fuel unit con-sumption of the cooling system is 0.82kg/GJ. Compared with the current energy consumption level of the cooling system (25.27 kg/GJ), it has great potential for energy saving. In order to verify the energy con-sumption evaluation model of cooling system, combined with Tongzhou refrigeration system scheme, four basic types of cooling systems including separate electric cooling, centralized electric refrigeration, sepa-rate thermal refrigeration, centralized thermal refrigeration were analyzed in calculation and compared with exergy analysis results. The results showed that the proposed model was consistent with the exergy analysis, energy consumption of electric refrigeration fuel was lower than the thermal cooling, the separate refrigeration fuel consumption was lower than the centralized refrigeration, centralized thermal refrigera-tion energy consumption was higher, which should be careful to develop. The proposed energy consump-tion evaluation model provided theoretical support for the unified evaluation of different types of cooling systems and provided a reference for the planning and design of urban cooling systems.