在北方寒冷地区,沼气工程加热系统如何能有效、合理地利用能源,提高能源利用率,是沼气工程实现低能耗,高产能必须解决的现实问题.该文依据地下水源热泵加热系统在沼气工程中应用的实例,建立了以?效率、热效率以及能级系数为评价准则的沼气工程加热系统能效分析模型,并通过对加热系统实际运行参数的测试,得到了沼气工程用户系统?效率为97.8%,地下水源热泵机组系统?效率为13.4%,沼气工程加热系统总的?效率为13.1%;加热系统总的热效率为85.3%;沼气工程用户耗热量的能级系数为0.161,用户供给热量的能级系数为0.164,地下水源热泵机组的能级系数为0.567.结果表明,对于沼气工程低品位热能用户,采用低温水供热科学合理;热泵机组系统回收了地下水中低品位热能,节约了高品位电能,加热系统能的数量有效利用程度较高;但热源与用户之间供需能质存在差异,在能质利用方面还需进一步完善.该结论可为今后沼气工程选择合理的加热模式提供参考依据.%Under the condition of low ambient temperature in the cold region of the northern China, in the event that biogas project really wants to run normally, it needs to be heated by external heat source Choosing a reasonable heating system for the biogas engineering can not only make the heating system of biogas project more effective and reasonable, but also improve the utilization rate of energy. In addition, choosing a reasonable heating system for biogas engineering is truly the typical practical problem that must be solved to realize the low energy consumption and high output of biogas engineering. According to the application example of the heat pump heating system with the groundwater resource in the biogas project, an energy efficiency analysis model taking exergy efficiency, thermal efficiency, and energy level coefficients as the evaluation criterion for the biogas project heating system was established. Through the measured parameters of ground water source heat pump heating system, the results are obtained as the follows: The user system's exergy efficiency of the biogas project is 97.8%; The exergy efficiency of the groundwater source heat pump unit is 13.4%; The total exergy efficiency of the biogas project heating system is 13.1%; The total thermal efficiency of the heating system is 85.3%; the energy level coefficient of the user's heat consumption in the biogas project is 0.161; the energy level coefficient of the user's supply heat capacity is 0.164, as well as the energy level coefficient of the groundwater source heat pump unit is 0.567. The results indicated that the application of ground water source heat pump heating system in biogas engineering is practical and feasible. For users of low grade thermal energy of the biogas project, the exergy efficiency of using low temperature water for heating is relatively higher, and the process of energy use is quite scientific and reasonable. Moreover, the heat pump unit system can not only recover the low-grade heat energy from the groundwater, but also save the high quality electric energy in a feasible way, so that the effective utilization degree for the amount of energy used in the heating system can be very high, however, there still exists a difference in the quality of supply and demand between the heat source and the users, and the further improvement is needed in the use process of energy quality. It is suggested that the heating system of biogas engineering should adopt the heating mode matching the energy level and use the low grade heat source to heat the biogas project and evaluate the process of energy utilization synthetically. The above conclusion can be used as a reference for selecting a reasonable heating mode for biogas engineering in the future.
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