基于西门子S7-200PLC的电除尘器低压控制系统的开发

针对粉尘污染净化治理中对电除尘器的实际需求,以西门子S7-200PLC为核心,设计电除尘低压控制系统,并进行了软件编程和硬件实现.给出了低压系统中的振打控制方法和时序以及加热、卸灰控制的方法.实验证明该系统合理有效.     

微机在锅炉设计计算中的应用

针对锅炉在设计计算中,大量数据均需要进行多次试算与叠代给设计过程带来较大工作量,提出采用计算机进行锅炉的热力计算,本文阐述了计算机在锅炉热力计算中发挥的作用和重要性,进而说明了计算机的计算方法和步骤,最后对设计中图表的处理作了简要说明。     

Life cycle cost analysis of new FRP based solar parabolic trough collector hot water generation system

Parabolic trough collectors （PTCs） are employed for a variety of applications including steam generation and hot water generation. This paper deals with the experimental results and an economic analysis of a new fibre reinforced plastic （FRP） based solar PTC with an embedded electronic controlled tracking system designed and developed for hot water generation in a restaurant in Madurai, India. The new collector performance has been tested according to ASHRAE Standard 93 （1986）. The performance of a new PTC hot water generation system with a well mixed hot water storage tank is investigated by a series of extensive tests over ten months period. The average maximum storage tank water temperature observed was 74.91℃, when no energy is withdrawn from the tank to the load during the collection period. The total cost of the new economic FRP based solar PTC for hot water generation with an embedded electronic controlled tracking system is Rs. 25000 （US$ 573） only. In the present work, life cycle savings （LCS） method is employed for a detailed economic analysis of the PTC system. A computer program is used as a tool for the economic analysis. The present worth of life cycle solar savings is evaluated for the new solar PTC hot water generation system that replaces an existing electric water heating system in the restaurant and attains a value of Rs. 23171.66 after 15 years, which is a significant saving. The LCS method and the MATLAB computer simulation program presented in this paper can be used to estimate the LCS of other renewable energy systems.     

我国北方地区清洁供暖技术现状与问题探讨

近年来,我国北方地区雾霾天气频发,京津冀地区尤为严重。受经济成本、取暖模式等诸多因素影响,短期内燃烧化石能源仍为北方地区冬季取暖的主要形式。推进我国北方地区冬季清洁取暖工作是中央提出的一项重要战略部署。文章回顾了区域供热技术发展的大致历程,介绍了近10年来国家相关的供热政策,详细比对分析了我国北方现有各项清洁供暖技术的优劣,包括:清洁燃煤供暖、天然气供暖、电制热供暖、地热供暖、生物质能清洁供暖、太阳能供暖、工业余热供暖、核能供暖等,最后对清洁供暖领域存在的关键共性问题进行了深入剖析,并探讨解决路径。为推进我国北方地区清洁取暖工作的可持续发展,建议今后围绕3个方面重点开展工作:(1)逐步建立清洁取暖科学评价体系,从全生命周期角度主要考量能效指标、经济指标和环境影响指标等性能参数;(2)有序推进供热管网节能改造和采暖末端能效提升,逐步健全现有供热系统评价体系,对于供热管网先评估后改造,逐一突破;(3)积极探索多方共赢长效机制,注重顶层设计与协调,加强区域政策配套与完善。     

水源热泵技术介绍

本介绍了水源热泵的概念，对水源热泵的工作要求、运行原理、性能特点和使用中的注意事项进行了详细说明。     

巷道底臌的治理与研究

根据爆破卸压的原理，在巷道底板通过爆破进行局部松动破坏形成一个松动圈，从而达到减缓或消除底臌，并研究单面卸压技术参数，对施工关键环节加以论述，为现场应用提供指导。     

Finite element study on impact sound transmission through a floating floor

To understand the characteristics of impact-sound transmission through a floor is very helpful for developing sound attenuation strategies to acquire a high quality of dwellings. Sound transmission through a floating floor to the room underneath was modeled by finite-element method (FEM). The sound pressure levels calculated by the FEM model on a scale of 1:4 was compared with the measured values, which demonstrate good agreement, particularly for impact sound of a relatively low frequency. The sound pressure level in a receiving room is strongly affected by the structural characteristics of both the floor and the room. The sound pressure transmitted through a clamped floor is lower than through a simply supported floor because of the larger rigidity of the clamped floor that contributes to the attenuation mechanism of stiffness. Increase in the thickness of the fiber-glass damping layer in the floor improves sound insulation. A larger room has a larger capacity to dissipate the sound pressure and thus has a lower sound pressure level. An asymmetric configuration of room avails sound attenuation because it has weaker structural and acoustic coupling than a symmetric one.     

Algorithm of heating temperature for Chongqing＇s winter greenhouses

Internal temperature is crucial to plant growth in the greenhouse. We investigated the patterns of constructing and managing greenhouses in Chongqing, and developed an algorithm of heating temperature for closed winter plastic greenhouses under the conditions of no man-made illumination, no ventilation and hot wind machine as the heating equipment which are the most adopted pattern of greenhouses in Chongqing area. The algorithm includes two functions of temperature outside the greenhouse, which calculate the values of the warming estimation coefficient （WEC） and the gap between temperatures inside and outside the greenhouse with the measured data of outside temperature, and then give the value of internal temperature; the heat rating of heating facilities required by a greenhouse can be determined by this algorithm with given values of floor area and internal temperature, measured outside temperature and calculated WEC. Verification of the algorithm demonstrates a desirable accuracy of estimation. Algorithms of computing heating temperature for greenhouses of different constructing and managing patterns and in different geographic conditions can also be derived in a similar way. This research presents a paradigm for developing a feasible method to fit out greenhouses with appropriate heating facilities, aiming at energy efficient and cost efficient production.     

提高低温热水地面辐射采暖系统节能及运行效果的探讨

介绍低温热水地面辐射采暖系统的特点,分析其在节能和运行方面存在的问题,并提出相应的解决措施。     

微波炉测定小麦粉中水分的含量

采用微波炉加热干燥测定小麦粉中水分含量 ,确定了微波干燥的最佳条件 :同时干燥三个2 .5 g左右的面样 ,微波功率 36 0 W、加热时间 6分钟。此法干燥迅速、节能高效 ,与烘箱法比较 ,测定结果无显著性差异