西北多因素耦合对户用生物质能与太阳能互补热电沼气联供系统的影响机理研究

It is the bottleneck of the exploitation of renewable energy to meet the energy demand continuously and steadily. In order to break it, a combined system for heating, power and biogas (CHPB) have been firstly proposed and developed with the integration of photovoltaic(PV) array, low-temperatured solar collectors and thermostat biogas digestor for the household use in Northwest China by the project group. The demonstration results show that the CHPB can basically meet the household energy demands of the power, biogas and winter heating steadily except cloudy days. To further improve the cost performance of the CHPB, in this project, at first, the influences on the annual output of heat, power and biogas would be experimentally studied about the solar radiation, sunshine duration, ambient temperature, humidity, wind speed, dust accumulation and shaded factor under actual conditions to get the working strategies of the maximum energy output. Then, while the energy guarantee rate keeps equal in accordance of the statistics of household energy consumption, the system would be optimized when it runs with the working strategies of the maximum energy output. The coupling expressions would be studied theoretically among the factors and the energy outputs of the optimized system. Subsequently, the performances of the optimized system would be studied experimentally and the expressions would be revised according to the experimental results. Then the thermodynamic performances and application scope of the optimized system would be studied in different regions of Northwest China. Finally, the coupling influence mechanism would be disclosed about multi-factors on household combined system for heating, power and biogas driven by biomass and solar energy in northwestern China. The results of the project will scientifically guide the popularization of the CHPB and have great significance for high-efficient exploitation of renewable energy at low cost in Northwest China.

连续稳定供能是可再生能源开发利用的“瓶颈”。为突破此“瓶颈”，项目组在国际上首次将光伏发电、低温太阳能集热和恒温沼气生产等装置集成，研发了适合西北的户用热电沼气联供系统，除阴天外，基本稳定地满足了用户电能、沼气和冬季采暖等用能需求。为了进一步提升系统性价比，本项目首先实验研究实际工况下不同运行策略时太阳辐射、日照时间、环境温度、湿度、风速、积灰量、遮挡系数等因素对原系统全年输出热能、电能和沼气的影响，获得最大产能运行策略；然后，根据用户用能统计数据，在供能保证率不变时，优化按照最大产能策略运行的系统，理论研究多因素与新系统输出产能之间的耦合关系式；接着，实验研究新系统的产能性能，利用实验结果修正耦合关系式，研究系统在西北地区的热力学性能和适用范围，揭示西北多因素耦合对热电沼气联供系统的影响机理。研究结果对推广应用热电沼气联供系统提供了科学指导，对高效低成本开发利用西北可再生能源有重要价值。

作为国际可再生能源研究的难点和热点问题，连续稳定供能是可再生能源开发利用的“瓶颈”。为突破此“瓶颈”，项目组在国际上首次将光伏发电、低温太阳能集热和恒温沼气生产等装置集成，研发了适合西北的户用热电沼气联供系统，除阴天外，基本稳定地满足了用户电能、沼气和冬季采暖等用能需求。为了进一步提升系统性价比，本项目开展了以下相关研究：. 1. 实验研究了实际工况下不同运行策略时太阳辐射、日照时间、环境温度、湿度、风速、积灰量、遮挡系数等因素对原系统全年输出热能、电能和沼气的影响，获得了最大产能运行策略。在热水器全天接收太阳辐射总量方面，只有在夏至时，横排管热水器全天接收太阳辐射总量高于竖排管热水器，在春分、秋分和冬至时，竖排管热水器全天接收太阳辐射总量明显高于横排管热水器。. 2. 根据用户用能统计数据，在供能保证率不变时，优化按照最大产能策略运行的系统，理论研究多因素与新系统输出产能之间的耦合关系式。分析确定了多个子系统协同互补模式；利用多产的电能延长水泵运行时间增加供暖热量，延长供暖时间，供暖太阳能保证率可提高7.01%，达到74.49%；结合多产的电能，加强集热量与散热器的换热频率，采暖季可多提供热能2338.90kW•h；改变联接方式减少掺混的影响，整个采暖季可以减少热量损失85.68kW•h。. 3. 实验研究了新系统的产能性能，利用实验结果修正耦合关系式，研究了系统在西北地区的热力学性能和适用范围，揭示了西北多因素耦合对热电沼气联供系统的影响机理。在太阳能资源三类地区全年日照时数不低于2200~3000h，全年太阳辐射总量大于1200kW•h/m2时，户用热电沼气联供系统可实现100%可再生能源连续稳定满足全年多层次的用能需求，即除湖南、湖北、四川、广西，贵州等地，全国大部分地区均可适用热电沼气联供系统来满足供能需求。. 研究结果对推广应用热电沼气联供系统提供了科学指导，对高效低成本开发利用西北可再生能源有重要价值，对西北地区巩固精准扶贫成果和生态环境保护有重要价值和意义。