冻土层中水平埋管换热器换热特性的数值分析

寒冷地区冻土层对地源热泵水平埋管换热器(GHE)的换热特性产生重要影响。根据冻土层换热特点建立了一种简化传热模型,对水平埋管周围土壤瞬态温度分布进行了模拟计算,分析了冻土层冻结和土壤含水率对GHE热损失的影响。计算结果表明,土壤冻结情况GHE的传热损失相对于非冻土情况下增大。进液管热损失随着土壤中含水量的增加先减小后增加,回液管热损失逐渐减小,GHE总热损失减小。计算结果与国家标准"地源热泵系统技术规"(GB 503662-2005)中对水平埋管的埋深规定相吻合。     

太阳能辅助地埋管地源热泵供热系统运行模拟

某工程拟采用太阳能辅助地埋管地源热泵联合供热系统.介绍联合供热系统流程,建立联合供热系统的数学模型,对最冷日集热器有效输出能量、供暖室内实际温度进行了模拟计算.     

地埋管地源热泵发展中的关键问题

介绍了地埋管地源热泵系统的优点,针对地埋管地源热泵出现的问题,重点探讨了地埋管地源热泵系统在岩土体热物性勘察、岩土体热平衡、地埋管换热器的设计与施工等方面应采取的措施。加上其他环节的紧密配合,以期为地源热泵系统健康发展提供参考。     

热泵系统中埋管物性参数对换热性能影响

以土壤源热泵系统中水平埋地换热管为研究对象,分别从埋管管材,埋管埋深以及埋管规格三个方面进行了分析与研究,总结出埋地换热管物性参数对埋管换热性能的影响。     

地埋管地源热泵系统的热平衡

地埋管事地源热泵系统的核心。文章首先阐述了地源热泵系统的定义及分类,然后探讨了地埋管地源热泵的工作原理,最后对某地埋管地源热泵土壤温度变化实测进行了分析。     

重庆市《地埋管地源热泵系统技术规程》解读

介绍了重庆市《地埋管地源热泵系统技术规程》的编制背景、特点并对重点条文进行了解读。《规程》在国家标准的基础上,结合重庆市气候、岩土条件特点及近年来的工程实践,对地埋管地源热泵系统工程的勘察、设计、施工及验收进行了完善,以提高重庆地埋管地源热泵系统的设计水平,实现节能减排的战略目标。     

土壤源热泵系统施工技术在东营软件大厦工程中的应用

土壤源热泵是一种利用土壤所储藏的太阳能资源作为冷热源,进行能量转换的供暖制冷空调系统,是清洁的可再生能源的一种新技术.笔者结合工程实际情况,详细介绍了土壤源热泵系统的优点、组成及施工工艺,并且重点介绍了室外地埋管换热器的施工工艺,为今后土壤源热泵空调系统施工质量控制提供了宝贵经验.     

地埋管地源热泵热水供应系统运行性能的影响因素

建立了地埋管地源热泵热水供应系统实验平台,研究了环境温度、间歇/连续运行工况、管内循环液流速等对地埋管换热器换热能力的影响,并研究了地埋管换热器周围土壤温度场的变化.结果表明,地埋管地源热泵热水供应系统基本不受环境温度的影响;采用间歇运行,有利于提高地埋管换热器的换热能力;地埋管换热器平均单位井深换热量随管内循环液流速的增大而增大,但当流速增大到一定程度时,其增幅趋于平缓.     

武汉地区地源热泵系统的运行测试与分析

对武汉地区典型住宅小区地下水地源热泵系统和地埋管地源热泵系统的运行测试数据进行了分析,获得了地源热泵系统夏、冬季工况下用户侧和地下侧的供回水温度变化规律、机组与系统的COP及运行费用.     

基于岩土体蓄能平衡的竖直地埋管换热器设计方法

针对地埋管运行换热性能,提出了基于岩土体蓄能平衡的地埋管地源热泵系统设计方法,主要涵盖了设计基础资料的提取、蓄能平衡原则的实现以及设计目标与方案的确立.阐述了地埋管换热特性及其对岩土体蓄能平衡的影响,在此基础上给出了基于蓄能平衡原则的地埋管地源热泵系统设计方法,并通过实验数据验证了该设计方法的有效性.     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

在市场中实践在实践中学习在学习中进步--工程公司市场化进程的回顾与展望

近两年来，工程公司在提高市场竞争意识、推动市场化进程中做了大量工作，其中坚持走出去的方针是我们自我加压、推行加快市场化步伐的一个重要战略步骤。     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

新形势下高校强化基建财务管理的探讨

在市场条件下高校基建财务人员在加强日常财务管理的同时,必须树立起高度的工作责任心,抓好事前监督、事中监督、事后监督三个环节,全面理解、贯彻执行《高等学校财务制度》,管好用好各项基本建设资金,提高基建财务管理水平,更好地完成高校各项基建任务,以有限的投资,最快的建设速度,获得最大的投资效益。     

2005年北京办公物业市场七大趋势

趋势一:CBD区域写字楼集中放量从各区域规划方案上看,CBD区域多数项目在03～04年处于项目的报批手续及拆阶段,预计2005年正式推向市场,因此2005年CBD区域将成为北京市场供应集中的域,区域即将供应的项目有北京财富中心(二期)、金地国际花园、万达广场、SOHO尚都、万通中心、世纪财富中心、怡禾国际中心、光华国际等。除去未知项目,2005CBD写字楼办公面积的供应量为60万平方米左右。中关村区域经过一段时间的集中供后开始逐步放缓,2005年供应的体量相对较大的项目有中关村金融中心、新中关。金街区域可能开盘的项目只有2个:英蓝国际中…     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

Variation in property taxation in Tulsa

Conclusions It may be reasonably concluded from this study that the range of variation in these ratios of assessed to actual value are of a reasonable size for the great majority of cases. The frequency distribution of these sample ratios was not normal, however, as was assumed a process of this type would produce. On the other hand, the failure of the regression analysis to identify any significant variables which would explain these variations would tend to re-enforce the assumption that the fluctuations were indeed of a random nature.To sum it up in one paragraph, aside from a few extreme cases, the assessing process appears to give estimates which are more consistent than would be expected under the assumption that any errors would be of a random nature, but the regression analysis was unable to isolate any particular socioeconomic characteristics which would explain the variation which was present.Financial support for this research project was furnished by the University of Tulsa.