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燃气机热泵总能系统的理论分析与试验研究

Experimental and Theoretical Investigations of Gas Engine-Driven Heat Pump Cogeneration System

【作者】 谢英柏

【导师】 阎维平; 马一太; 樊泉桂;

【作者基本信息】 华北电力大学(河北) , 热能工程, 2003, 博士

【摘要】 随着天然气在我国的广泛使用和电力空调引发的电力危机,利用天然气的热机热泵的研究逐渐受到重视。对斯特林、汽轮机、燃气轮机和内燃机几种热机热泵的动力选择分析结果表明:采用燃气机驱动热泵是一个比较好的选择。在介绍燃气机热泵的工作原理和系统特点之后,对燃气机热泵在我国的应用的可行性进行分析。认为机组在东北地区应采用燃气锅炉进行辅助加热,并采用交替运行方式;在黄河流域应用应按供热工况设计;在长江流域应用应按空调工况设计;在华南地区应用则可以缓解夏季电力紧张。 为了深入了解燃气机热泵的节能效果,本文进行了热力学第一定律、(火用)分析、能级分析和热经济学分析。结果表明:燃气机热泵在供热时的一次能源利用率为1.76,(火用)效率为29.12%。对比发现,燃气机热泵的一次能源利用率和(火用)效率均高于电动热泵、燃气锅炉、燃煤锅炉和电锅炉;对燃气机热泵系统的能级分析也表示系统的能量利用过程比较合理;通过热经济学的分析,得出燃气机热泵的供热(火用)成本为11.2元/GJ,这个价格与现行集中供热的价格相比还是很有优势的。这反映了燃气机热泵是一项高效节能技术。由于能级平衡理论分析考虑了(火无)的作用,而热泵供暖时其性能系数的提高主要是利用了环境热量,所以建议采用能级平衡理论来分析评价热泵的性能。 为了实际验证燃气机热泵技术的可行性,搭建和改进了实验台。改进后的实验台噪音明显降低。综合试验结果:燃气机热泵是一项高效节能技术,其一次能源利用率PER在试验条件下为1.13~1.79。随着转速的降低,发动机效率增大;而系统的性能系数COP和EER虽有下降,但下降不多,且在很大范围内保持不变。这说明燃气机热泵部分负荷特性好,可以很好的实现变速调节。 工业生态学是从大系统的角度研究大系统中各子系统之间的能量流、物质流和价值流。总能系统则主要研究系统中各环节的多种能量流之间的配合关系与转换利用,以达到最佳效果。二者有相似之处,可以类比。工业生态学的生态学研究视角、生命周期评价方法和能量冗余性可以拓展总能系统的理论。而总能系统的(火用)分析、能级平衡理论和热经济学分析方法可以丰富工业生态学评价方法。 提出了一个基于燃气机热泵的热、电、冷三联供总能系统。并进行燃气机与压缩机,燃气机与发电机之间的负荷匹配分析。定义了燃气机与压缩机的几何匹配准则式X1和燃气机与发电机的几何匹配准则式X2。分析了燃气机与压缩机的匹配时制冷剂与燃料之间的流量匹配。为了进行燃气机热泵总能系统的节能评价,提出了标准气耗概念。分析结果表明:燃气机热泵的热、电、冷三联供总能系统的标准气耗仅为热、电、冷分供系统的一半左右。

【Abstract】 The investigations on heat engine driven heat pump utilizing natural gas are now come in for people’s attention with the vast popularization use of natural gas in our country and the power crisis caused by large use of electric air conditioning. Employing gas engine to drive heat pump is better choice compared to Stirling engine, turbine and gas turbine under today’s condition. After introduce the operating principle and system characteristic of GEHP (gas engine-driven heat pump), the author discuss the application feasibility in China. The author deems that the using of the GEHP in northeast area of China should using gas boiler for assistant heating up, moreover, the operating mode should in alternation manner. In Yellow River valley the GEHP should be designed in heating mode, but in Yangtze River valley we should take air conditioning mode. The using of GEHP in South China region can reduce the power intensity in summer.For thoroughly know the energy saving effect of GEHP, The thermodynamics analysis is processed with the first law of thermodynamics, exergy theory, energy grade theory and thermoeconomic method. The results show, when heating, the primary energy ratio of GEHP is 1.76 and exergy efficiency is 29.12%. Which are higher than electric driven heat pump, gas boiler, coal boiler and electric boiler. The energy grade theory analysis results also show that the energy utilization of GEHP is comparatively reasonable. Exergy cost of GEHP is 11.2 yuan/GJ by thermoeconomic method, which is much lower than the heating price nowadays. All the results indicate that GEHP has upper thermodynamics perfect than other heating equipment, and is of high efficient energy saving technology. Among these method, energy grade theory considering the using of anergy. Because the improvement of coefficient of performance of the GEHP mainly due to the use of waste heat from surroundings, we suggest that we should use energy grade theory to evaluate the performance of heat pump.The author build and improve GEHP’s experiment set to validate the feasibility of this technology. Noise of the GEHP debase obviously after upswing. The results show that GEHP is of high efficiency energy saving technology. The primary energy ratio is between 1.13-1.79 under experimental condition. When the gas engine speed down, the efficiency of gas engine go up, but the COP and the PER drop. The descendant value is small and keeps stable in large area. All this indicate that GEHP has good part load characteristic and fit for variable speed adjustment.Industrial ecology investigates the energy flow, substance flow and value flow among each subsystem using whole system viewpoint. Cogeneration system mainly investigates the relationship and the conversion of multi-kind energy flow among each components of a system. What their aim are to get the best purpose. So there are much analogy exists between them. The ecology investigate viewpoint, life cycle assessment and energy redundancy degree will develop the theory of cogeneration, while the exergy analysis, energy grade theory and thermo-economic method also enrich the evaluation method of industrial ecology.A gas engine driven heat pump cogeneration system for combined heat, cold and power production is put forward and represented in this paper. Load matching between gas engine and compressor, gas engine and generator is processed. The rule formula X1 and X2 are defined. X1 indicates the load matching of gas engine and compressor, X2 indicates the load matching of gas engine and generator. And the flow matching between refrigeration of the compressor and fuel of the gas engine is also processed. To evaluate the thermodynamics perfect of this system, the concept of standard gas consumption is defined. Analysis of the system indicates that the primary energy ratio of this system is 1.85, which is double than that of the conventional separated production system, and the cogeneration system saves about 57% standard gas consumption in comparison of the conventional separated production system.

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