我国各类独立供暖系统的散热器比较分析

供暖系统一般可以分为集中供暖和独立供暖两种。集中供暖是指供暖系统服务对象为整个城市、一个或几个建筑群、建筑物的供暖方式。而独立供暖系统只对单个业主单元服务。我国的传统供暖地区主要采用城市热力管网和小区锅炉房集中供暖,而一些新兴供暖地区或一些新建节能型住宅则越来越多的选用独立供暖系统供暖。     

地源热泵-燃气锅炉供暖系统的动态经济评价

针对燃气锅炉能源利用率偏低、废气排放多等问题,结合工程实际,利用经济分析的方法,对燃气锅炉供暖系统和地源热泵供暖系统分别从初投资、年运行费用、维护费用等方面进行分析。结果表明,地源热泵系统的初投资比较高,但由于运行费较低,根据费用年值及费用现值的计算,地源热泵系统在整个寿命期内的费用明显低于燃气锅炉供暖系统,因此,地源热泵系统比燃气锅炉系统具有更高的经济效益。     

集中供热、燃气锅炉及电热供暖系统的经济分析

对采用集中供热，燃气锅炉及电热供暖系统分别进行了经济比较，其结果表明集中供热系统运行费用最低，电热供暖系统运行费用最高；电暖器供暖系统初投资最低，除集中供热地板供暖系统之外顶棚电热膜供暖系统初投资最高。     

壁挂冷凝式燃气锅炉与热地板在户式供暖系统中的应用

指出了现有户式供暖系统的缺点，分析了冷凝式锅炉和地板供暖系统各自的优点，介绍了壁挂冷凝式燃气锅炉与热地板联合的户式供暖系统形式。     

三种不同电采暖方式的技术经济分析——以石家庄某民居为例

电能作为一种清洁能源,对于减少煤炭使用、实现清洁供暖具有重要意义。结合石家庄某民居热负荷数据及当地政策,对三种不同电采暖方式和壁挂式燃气锅炉进行对比分析,结果表明:太阳能热泵+谷电蓄热供暖系统20年生命周期内最具经济性;相变蓄热式电锅炉供暖系统炉配网增容大,不具备推广价值;空气源热泵+谷电蓄热供暖系统与壁挂式燃气锅炉供暖系统各项费用相当,但具有削峰填谷和新能源消纳的优势,且在华北地区运行效果最佳,可作为大规模推广方式。     

辅助热源对主动式太阳能供暖系统节能性的影响

根据太阳能贡献率和辅助加热设备的能源效率,将系统的能耗折算成一次能源,分析不同辅助热源对太阳能供暖系统节能性的影响,认为主动式太阳能供暖系统要达到节能效果必须满足一定的前提条件。研究结果表明:辅助热源方式和太阳能贡献率对系统的节能性影响很大;相对于燃气锅炉单独供暖,电加热辅助太阳能供暖系统只有在太阳能贡献率高于65.4%时才节能,而大多数系统的太阳能贡献率很难达到这么高,因此要尽量避免使用;热泵辅助太阳能供暖系统在大多数情况下都是节能的(热泵的平均COP=2.5时,太阳能贡献率需高于7%);采用平均COP高于3.0的热泵或采用燃气锅炉作为辅助热源时,系统都是节能的,太阳能贡献率越高,节能效果越明显。     

严寒地区区域供暖系统优化方案技术经济性分析

严寒地区既有供暖系统改造作为我国老旧小区综合改造和性能提升的重要内容,是缓解我国环境问题和资源紧张的重要途径和关键环节。基于“煤改气”、“煤改电”政策对燃气锅炉供暖系统、空气源热泵复合供暖系统进行技术与经济分析,旨在为我国严寒地区区域供暖提供重要的参考价值。     

燃气锅炉不同供暖系统形式的适用性分析

针对不同类型的燃气锅炉及相应的供暖系统形的适用性作了全面的分析及比较。指出了在选择供暖系统形式时应注意的问题。     

郑州地铁车辆段供暖热源及输配系统设计的几点思考

供暖系统的热水循环泵的耗电量巨大,燃气锅炉的燃气消耗量及其成本费用等是地铁车辆段冬季运行的能耗主要来源,相应的设计内容也尤为重要。地铁车辆段的供热热源及其输配系统的设计,分别采用气候补偿措施、烟气热回收装置和二级泵系统措施,对供暖系统的能耗以及节能效果有较大的作用。     

严寒地区某燃气锅炉房供热效果分析

本文采用燃气锅炉做热源,为某小区四栋高层住宅散热器供暖系统提供热水,施工完毕,供暖系统进行调试,住宅各房间室温初始温度未达到设计要求,经从锅炉燃烧器型号、板式换热器温差、热水循环泵、外网分支阀门、入户热计量表、过滤器等检查调试,发现存在问题,继而优化供热方案,最后室温达到规范设计值。     

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.     

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。     

谈城市历史保护规划的误区

由于缺乏起码的历史文化知识,忽视历史文化遗产的保护,错误的决策导致了建设性的破坏,要加强城市保护的教育,培养合格人才。     

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。     

浅谈建筑施工临时用电安全

针对由于建筑施工临时用电安全管理的不完善和不规范操作而导致大量工伤事故频频发生的问题,为消除用电安全隐患,对建筑施工临时用电安全管理进行了归纳和分析,并提出了整改意见,以确保现场人员及电气设备的安全运行。     

Perchlorate exposure in lactating women in an urban community in New Jersey

Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average ± SD perchlorate level in drinking water, breast milk, and urine was 0.168 ± 0.132 ng/mL (n = 253), 6.80 ± 8.76 ng/mL (n = 276), and 3.19 ± 3.64 ng/mL (3.51 ± 6.79 μg/g creatinine) (n = 273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16 ± 11.33 μg/g creatinine, p = 0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤ 1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r = 0.626, p = < 0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants.     

安康市工程施工企业未来几年人才需求调查

为了不断提高工程类专业的办学质量,对安康市区主要施工企业或项目经理部未来几年人才需求状况进行了调查,同时提出相关建议,以期培养更多的该类专业人才,满足施工企业需求。