This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizin...This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.展开更多
Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant ...Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant growth directly and then bring about further influence to the health of human and animals by food-chain.So it is significant to study the transport and transformation of the selenium in the soil profile.展开更多
智能软开关(soft normally open point, SNOP)凭借其灵活的功率调节能力逐渐应用于配电网中。但由于大量分布式电源(distributed generation, DG)接入,SNOP受到线路容量的限制,调节能力有限。为发挥其最大调节能力,文中提出适用于配电...智能软开关(soft normally open point, SNOP)凭借其灵活的功率调节能力逐渐应用于配电网中。但由于大量分布式电源(distributed generation, DG)接入,SNOP受到线路容量的限制,调节能力有限。为发挥其最大调节能力,文中提出适用于配电系统的SNOP对线路有功功率裕度调节灵敏度的定义,将其作为SNOP调节能力的评价指标,由此建立SNOP的选址优化模型。在此基础上,引入系统节点电压裕度以及线路功率裕度2个安全评价指标,构建以综合运行裕度最大为目标函数的配电网运行优化模型。将上述模型转化为二阶锥模型,通过MATLAB工具实现该问题的有效求解。最后,通过改进的IEEE 33节点算例对所提模型与求解方法进行验证,进一步表明了所提选址方法能够发挥SNOP的最大调节作用,优化控制策略可以实现配电网安全经济运行。展开更多
依托高压气源,建立了高压临界流文丘里喷嘴气体流量标准装置。在小流量的校准实验中,标准临界流文丘里喷嘴(CFVN)阵列上游的温度场分布对测量不确定度具有重要影响。针对标准CFVN阵列上游的温度场,在喉径8.251 mm CFVN的校准实验中,分...依托高压气源,建立了高压临界流文丘里喷嘴气体流量标准装置。在小流量的校准实验中,标准临界流文丘里喷嘴(CFVN)阵列上游的温度场分布对测量不确定度具有重要影响。针对标准CFVN阵列上游的温度场,在喉径8.251 mm CFVN的校准实验中,分析和对比了3种不同标准CFVN阵列组合方式以及不同流量下的温度场分布特性。实验结果表明:小流量下,标准CFVN阵列上游的最大温差为1.97 K,随着管内流量增加,温度场分布不均匀性降低;3种不同标准CFVN阵列组合方式下,阵列上游最大温差在1.10~1.97 K之间变化。因此,为提高滞止温度测量精度,需要优化小流量下的温度测量方法。展开更多
基金Project(50838009) supported by the National Natural Science Foundation of ChinaProjects(2006BAJ02A09,2006BAJ02A13-4) supported by the National Key Technologies R & D Program of ChinaProject(CSTC,2008AB7110) supported by the Key Technologies R & D Programme of Chongqing,China
文摘This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.
文摘Selenium is a useful element in plant growth and it’s also an necessary ingredient for animal life.The inadequateness or excessiveness of selenium content and different forms of selenium in soil can affect the plant growth directly and then bring about further influence to the health of human and animals by food-chain.So it is significant to study the transport and transformation of the selenium in the soil profile.
文摘智能软开关(soft normally open point, SNOP)凭借其灵活的功率调节能力逐渐应用于配电网中。但由于大量分布式电源(distributed generation, DG)接入,SNOP受到线路容量的限制,调节能力有限。为发挥其最大调节能力,文中提出适用于配电系统的SNOP对线路有功功率裕度调节灵敏度的定义,将其作为SNOP调节能力的评价指标,由此建立SNOP的选址优化模型。在此基础上,引入系统节点电压裕度以及线路功率裕度2个安全评价指标,构建以综合运行裕度最大为目标函数的配电网运行优化模型。将上述模型转化为二阶锥模型,通过MATLAB工具实现该问题的有效求解。最后,通过改进的IEEE 33节点算例对所提模型与求解方法进行验证,进一步表明了所提选址方法能够发挥SNOP的最大调节作用,优化控制策略可以实现配电网安全经济运行。
文摘依托高压气源,建立了高压临界流文丘里喷嘴气体流量标准装置。在小流量的校准实验中,标准临界流文丘里喷嘴(CFVN)阵列上游的温度场分布对测量不确定度具有重要影响。针对标准CFVN阵列上游的温度场,在喉径8.251 mm CFVN的校准实验中,分析和对比了3种不同标准CFVN阵列组合方式以及不同流量下的温度场分布特性。实验结果表明:小流量下,标准CFVN阵列上游的最大温差为1.97 K,随着管内流量增加,温度场分布不均匀性降低;3种不同标准CFVN阵列组合方式下,阵列上游最大温差在1.10~1.97 K之间变化。因此,为提高滞止温度测量精度,需要优化小流量下的温度测量方法。
