温室蔬菜大棚生物质能火墙供暖系统

Biomass Fire Wall Heating System for Vegetables Greenhouse

传统温室大棚受气候条件限制,难以在恶劣条件下满足作物生长对热环境的需求。提出一种以玉米秸秆等生物质为一次能源输入的温室大棚火墙供暖系统。该系统由烟气发生装置、烟气处理装置、末端换热装置、烟气输送管网和动力机组成,通过燃烧秸秆等农林废弃物制备一定温度烟气并将烟气滤后通过火墙散热末端满足温室大棚热环境条件的需求。其中,火墙散热末端是系统关键组成部分。基于计算流体动力学(computational fluid dynamics,CFD)数值模拟平台,分析与优化散热火墙关键设计参数,并分析不同工况下系统性能,搭建全尺寸实验平台,验证该系统的热力性能,并与传统无供暖的温室大棚进行对比。研究结果表明,生物质能供热火墙最优物理结构参数为:烟气流通孔道左右两侧对称排布,管径为63 mm,隔热层铺设深度为20 cm。当烟气温度高于130℃、烟气流速超过3 m/s时,该系统能满足温室大棚热环境条件的需求。从能耗和经济性方面考虑,最优运行参数为:烟气温度130℃、烟气流速3 m/s。在夜间最不利工况下,生物质能供暖火墙系统作用下的温室空气平均温度提高了4.3℃。在其他工况下,温度提升幅度最大为5.8℃,最小为3.3℃。该研究对于科学应用秸秆等生物质,改善温室大棚热环境具有十分重要的意义。研究所得到的示范系统设计参数可以直接用于实践,为其他类似系统设计提供有效参考。

Traditional greenhouses are limited by climatic conditions,which is difficult to meet the demand for thermal environment for crop growth under harsh conditions.In order to solve such problems,a greenhouse fire wall heating system taking corn stalks or other biomass as primary energy input was proposed.The system consists of a burner,a flue gas treatment device,a fire wall,a pipe network and a power machine.The flue gas was prepared at a certain temperature in the system by straw burning or other agricultural and forestry wastes burning,and was filtered and passed into the fire wall for heating,meeting the heat demands.In the system,the fire wall is the key component of the system,which was analyzed in a further way.In order to evaluate the performance,the key design parameters of the fire wall was analyzed and optimized by help of the computational fluid dynamics(CFD)numerical simulation platform,and the system performance under the different working conditions was analyzed.A full-scale experimental platform was built to verify the thermal performance of the system and compared with a traditional greenhouse without heating.The research results show that the system can obtain a satisfied performance while the design parameters of the fire wall are as follows:the flue gas flow channels are symmetrically arranged on the left and right sides,the pipe diameter is 63 mm,and the insulation layer is laid to a depth of 20 cm.The operating parameters are as follows:the flue gas temperature is higher than 130°C and the flue gas velocity over 3 m/s.Judging from energy and economic viewpoints,the system can obtain best system performance,while flue gas temperature is 130°C and flue gas velocity is 3 m/s.Greenhouse indoor air average temperature can be increased by 4.3℃at night.In other conditions,the maximum temperature increase is 5.8℃,and the minimum temperature is 3.3℃.This research is of great significance for the scientific application of biomass such as straw and improving the thermal environment of greenhouses.The design parameters of the demonstration system obtained by the research can be directly used in practice,providing an effective reference for other similar system design.