ANALYSIS ON THE SPATIAL DISTRIBUTION VARIATION CHARACTERISTIC OF URBAN HEAT ENVIRONMENTAL QUALITY AND ITS MECHANISM——A Case Study of Hangzhou City

Urban heat environmental quality (UHEQ) is affected by the interacting of weather condition and underlying surface framework of urban area. In the last two decades, many researchers from domestic and overseas have studied many problems at the aspect of urban heat environment such as urban heat islands, urban air temperature and their relation with urban land cover, city population, air pollution etc. In the recent years, Hangzhou, acting as a center city of Zhejiang Province in China, its urbanization quantum and quantity have both changed greatly, in particular, representing as business affairs building, resident real property and all kinds of specialty market having arisen in built-up zone. Based on Landsat TM images data in 1991 and 1999, urban underlying surface temperature value and Normalized Difference Vegetation Index (NDVI) were calculated using image interpreting and supervised classification technique by remote sensing software ERDAS image 8.4. The relation model between urban underlying surface temperature (UUST) and urban air temperature was setup according to the certain correlation pattern. Reference to the relational standard of assessing human comfort and other meteorology data of Hangzhou City in summer, the spatial distribution characteristic and the spatial variation degree of human comfort of heat environmental quality are estimated and mapped on a middle scale, that is, in six districts of Hangzhou City . Then the paper reveals the main characteristic of spatial variation from 1991 to 1999. Lastly, the change mechanism is analyzed and discussed from the viewpoint of city planning, construction and environmental protection.

Analysis of Heat Environment Indexes Using Integrated Remote Sensing and Site Measurement Techniques in a Community

Remote sensing and on-site measurement are used to determine the heat environment within a community,and are compared the differences for heat analysis. The two methods perform differently for various underlying surfaces. The individual methods can detect different aspects of the heat environment,which used in combination are useful for heat island research. The differences in estimated air and surface temperatures are smaller in open space and more obvious for vegetated surfaces. Ventilation does not affect the difference between air and surface temperature in open areas,and the vegetation surface and shading moderates surface temperature more effectively than the water surface; The forest is a type of underlying surface with heat comfortable,in which the feeling of air temperature is much difference to the structure of heat environment that should be survey and detected separately. The two methods can be used to study different aspects of the heat environment,thus forming a comprehensive approach for planners in urban and rural spaces.

Increasing the Efficiency and Level of Environmental Safety of Pro-Environmental City Heat Supply Technologies by Low Power Nuclear Plants

In connection with the current prospect of decarbonization of coal energy through the use of small nuclear power plants (SNPPs) at existing TPPs as heat sources for heat supply to municipal heating networks, there is a technological need to improve heat supply schemes to increase their environmental friendliness and efficiency. The paper proves the feasibility of using the heat-feeding mode of ASHPs for urban heat supply by heating the network water with steam taken from the turbine. The ratio of electric and thermal power of a “nuclear” combined heat and power plant is given. The advantage of using a heat pump, which provides twice as much electrical power with the same heat output, is established. Taking into account that heat in these modes is supplied with different potential, the energy efficiency was used to compare these options. To increase the heat supply capacity, a scheme with the use of a high-pressure heater in the backpressure mode and with the heating of network water with hot steam was proposed. Heat supply from ASHPs is efficient and environmentally friendly even in the case of significant remoteness of heat consumers.

Numerical Investigations on Supercritical Heat Transfer Characteristics of Environmental Friendly Refrigerants

The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids;however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a;however, safety issues should thoroughly concern its mild flammable characteristics.

Environmental Impact Assessment for an Absorption Heat Transformer

This study presents the environmental impact assessment of an absorption heat transformer designed to recover 1 kW of thermal energy from each 2 kW of waste heat supplies. The net contribution of the heat transformer is a load avoided of 0.665 kg CO2 equivalents;the recovery process avoids 0.729 kg CO2 equivalents and the major contribution to the environment impacts is the pumping process with 0.0437 kg CO2 equivalents for each 1 kWh recovered. The study results show that absorption heat transformer is a good environmental option because it produces useful energy from waste heat and the final result is an environmental impact diminution.

The mRNA Expression Profiles of Five Heat Shock Protein Genes from Frankliniella occidentalis at Different Stages and Their Responses to Temperatures and Insecticides

The westem flower thrips, Frankliniella occidental＆ （Pergande） is a highly invasive pest that is able to exploit many crops across a wide range of environmental conditions. Five full-length cDNAs of heat shock protein （HSP） genes （Fo-HSP90, Fo-HSP70, Fo-HSP60, Fo-HSP40 and Fo-HSP28.9） were cloned from F. occidentalis, and their expression profiles were investigated under conditions of thermal stress and insecticide exposure, and at different stages during development, using real-time quantitative PCR. All five gene sequences showed high similarity to homologs in other species, indicating the conserved fimction of this gene family. HSP60 represents an informative phylogenetic marker at the ordinal taxonomic level within Insecta, but HSP90, which has two homologous copies in Hymenoptera, was not informative. The expression of Fo-HSPs under thermal stress suggests that Fo-HSP90, Fo-HSP70, and Fo-HSP28.9 are inducible by both cold and heat stress, Fo-HSP40 is only heat-inducible, and Fo-HSP60 is thermally insensitive. There were two patterns of cold induction of Fo-HSPs： one is from 0 to 4℃ and the other is around -8℃. All five Fo-HSPs genes were induced by exposure to sublethal concentrations of the insecticide avermectin. The expression of the five Fo-HSPs during different developmental stages suggests that they all play a role in development of F. occidentalis.

The acclimatization to extreme environments and its physiological mechanisms

Acclimatization is a process of biological adaptation when exposed to environmental factors such as hypoxia,cold and heat for prolonged periods of time,where non-genetical variations play a role in allowing subjects to tolerate hypoxic,cold or hot environments.This review focuses on the characteristics and mechanisms of acclimatization found through major research advances by our institute.First,the mechanisms underlying the acclimatization to extreme environments are complex.In our investigations,the physiological changes of multiple systems including the nervous,circulatory,respiratory,and hemopoietic system were demonstrated when the acclimatization to hypoxia was developed,and the underlying significance of hypoxia-inducible factor-1(HIF-1) was investigated.Second,it is suggested that the development of acclimatization to extreme environments is complicated.Hypoxia and cold coexist at high altitude.Our investigations revealed the characteristics of negative cross-relationship in the acclimatization to hypoxia and cold.And third,it is interesting for us to understand that acclimatization to extreme environments is transferable among individuals,and the characteristics of heat acclimatizationinducing factor(HAIF) were presented.The above findings will provide a theoretical guidance for protective operations and help to establish a solid foundation for future research related to acclimatization.

Comprehensive Benefit Analysis of Direct Expansion Ground Source Heat Pump System

Direct Expansion Ground Source Heat Pump (DXGSHP) system directly extracts heat or cold energy from ground by consuming electricity to provide for space conditioning. Compared with the currently widely-used secondary loop Ground Couple Heat Pump (GCHP) system, it has higher energy efficiency, lower operating costs, and less environmental impact. A case study is carried out in this paper. The subject is a residential building located in Beijing, China. It is assumed that the building adopts the DXGSHP system and the GCHP system respectively. Annual loads and energy consumption are simulated and computed. Then the initial cost, operating cost and CO2 emission are calculated. The economic benefit is analyzed with the Payback Time method and the Dynamic Annual Cost Value method. The environmental benefit is discussed mainly by comparing the CO2 emission savings. The results show that the DXGSHP system has higher initial costs, but lower operating costs, and less greenhouse gas emissions. The DXGSHP system has better comprehensive benefits than the GCHP system.

燃烧热测定实验的课程思政设计——农林废弃物的热值测定

燃烧热测定是一个经典的物理化学实验。本案例将燃烧热测定与农林废弃物燃烧发电对接,对实验内容进行了适当调整,让学生了解燃烧热测定对保障发电厂安全运行的重要意义,以及农林废弃物燃烧发电对服务“三农”、乡村振兴和“双碳”战略的重要意义,提高了学生学以致用的能力,激发了学生的学习兴趣,引导学生关心国家能源安全、环境保护、可持续发展和人民的生命健康,对提升学生的能力和素质发挥了良好作用。

显热回收通风系统在华北肉种鸡舍应用效果研究

本试验旨在研究显热回收通风系统(sensible heat recovery ventilation,SHRV)在寒冷地区肉种鸡舍的运行效果,选择两栋同类型的鸡舍,对照舍采用锅炉供热,试验舍关闭7/10的供热管并加装1套SHRV,进行SHRV应用效果和热回收性能评价。结果表明,与对照舍相比,试验舍内平均温度降低约0.5℃,差异不显著(P>0.05),相对湿度、CO_(2)浓度、NH_(3)浓度略有升高,差异不显著(P>0.05);两栋鸡舍内不同位置温度和NH 3浓度存在极显著差异(P<0.01);SHRV的显热回收效率为64.96%~78.95%,能效比平均为4.1,运行SHRV每月降低成本1.05万元。研究表明,在该地区运行SHRV能够回收鸡舍排出废热的64%以上的热量,降低养殖成本。

Applicability of sewage heat pump air-conditioning system

A sewage heat pump system and its application based on a project in Chongqing,China,were discussed. Based on the sewage conditions,a feasibility analysis of the sewage heat pump air conditioning system was conducted. The theoretical and quantitative calculations indicate that sewage flux in the city sewage main pipe in the project can satisfy heat exchange requirements,and taking water from the pipes has relatively small influence on the pipe net in summer and winter. The sewage heat pump air-conditioning system can save 21.5% operating cost in one year,which is energy efficient and environmentally friendly.

溴化锂吸收式余热回收机组的设计

针对核电站低温余热回收利用的问题,将海水淡化技术与基于吸收式热交换的热电联产集中供应技术相结合,设计了一个溴化锂吸收式余热回收机组。该机组主要由蒸发器、吸收器、发生器、冷凝器、溶液热交换器、节流装置、溶液泵、冷剂泵等组成。验证分析表明:该机组可有效回收高温海水的余热,并用于淡化海水,在所需制热量为28784 kW的前提下,按年利用7200 h计算,全年海水的余热回收量约280000 GJ,全年淡水产量约2160000 t,减少了对生态环境的影响,大大提高了经济效益。因此该机组可为溴化锂吸收式热泵机组的优化设计提供良好参考。

奶牛热应激调控措施研究进展

随着奶牛养殖业趋向集约化和全球变暖日益加剧,热应激成为制约奶牛生产性能提高的重要因素之一,对奶牛的泌乳性能、机体健康和繁殖性能等造成了严重危害。因此,如何缓解热应激对奶牛生产的影响受到了普遍关注。本文通过整理近年来相关研究,从牛舍、日粮和遗传育种等角度论述了降低奶牛热应激影响的具体措施,以期为奶牛的健康养殖提供参考。

空间环境控温热沉结构优化试验

以板式热沉为试验对象,完成了板式热沉的测温试验以及板式热沉与笼式热沉的数值研究。数值计算考虑管网内部气体介质为高雷诺数湍流流动,采用标准k-ε涡粘模型,将数值计算与试验结果对比以验证其可信度。结果表明:额定工况点板式沿程压力损失约为50865Pa,笼式热沉压力损失约为80692Pa。流量越大,沿程阻力损失越大,两种热沉表现为同样的分布规律。热沉几何参数接近的情况下,流量对热沉内部流速有决定作用,布局方式基本不影响。在进口介质温度相同时,同一热沉流量越大,进出口温度差越小,增加流量能减小热分布不均匀性,使温差减小,温度趋于均匀的物理事实。笼式热沉进出口温差普遍高于板式热沉,说明板式热沉有较好的热均匀性。研究结果对今后热沉结构设计有指导意义。

共晶物相变蓄热材料制备及性能测试的实验设计

节能减排是当今社会的关注重点。利用共晶物相变蓄热材料在相变过程的蓄放热技术是实现太阳能、工厂余热等能源综合利用、提高能效、降低二氧化碳排放、保护环境的最有效手段之一。共晶物相变蓄热材料实验涉及原料配方及制备工艺、晶体结构及形成机理以及产品热物性能等专业内容,可设计为综合化学实验。该课题的实施培养大学生配方设计能力和大型仪器设备动手操作技能。

Thermophysical Properties and Supercritical Heat Transfer Characteristics of R515A

The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternative to replace conventional R134a, which can be beneficial for climate change. A considerable suggestion is R515A which possesses considerably lower global warming potential. The present simulations are designed to study supercritical fluid R515A under cooling conditions in horizontal position. The effect of pressure, mass flux, heat flux and tube diameter were considered for horizontal tube in the vicinity of pseudo critical temperature. Numerical investigations on heat transfer characteristics of supercritical fluid R515A were performed using widely used shear-stress transport (SST) model. Moreover, heat transfer correlations were developed and suggested to accurately predict Nusselt number within 10% accuracy. The simulation results showed about 3.98% average absolute deviation.

附加阳光房取暖技术在西藏农牧区应用的环境效益

西藏太阳能资源丰富,建设附加阳光房可以充分利用太阳能,减少取暖用燃料的使用,从而有效降低燃烧污染物的排放。问卷调查发现,西藏农牧民普遍认可附加阳光房的建设对室内空气品质的改善作用,认为室内空气品质好的家庭由改造前的38.5%大幅提升至68.5%。取样监测数据显示,取暖季附加阳光房的建设前室内CO平均体积分数、PM2.5平均质量浓度、PM10平均质量浓度均高于改造后,仅TVOC (Total Volatile Organic Compounds,总挥发性有机化合物)平均质量浓度低于改造后。同时,附加阳光房的普遍建设可以有效改善局部地区空气质量,监测数据显示试点工程建设区域PM2.5和PM10等的质量浓度出现明显下降,证实附加阳光房的建设可以有效改善农牧民生活区域的空气质量,为西藏清洁取暖工作提供了一种新思路。

基于质子膜的尿残液膜蒸馏影响因素研究

针对尿残液强酸强腐蚀性、物质含量高的特点,开发以质子膜为介质的间接加热气扫式膜蒸馏技术,完成尿残液的水分回收,以进一步提高空间站环控生保系统水资源闭合度.对比研究了7种质子膜材料的气相和液相两种接触模式下的蒸馏速率,获得质子膜材料的主动吸水、水分传输和尿残液耐受能力等特性.建立了尿残液液相接触模式下的传质传热理论模型,考察了质子膜厚度、尿残液物质浓度、进气流量、进气湿度和进气温度等5个主要变量对蒸馏速率的影响规律,其中进气湿度对蒸馏速率有着相对较大的影响.理论计算所得蒸馏速率与实测值之间的相对标准偏差为5.8%,验证了模型的有效性.研究结果为尿残液水分回收技术的开发和应用提供了理论和实验依据.

高频感应热辊在转移印花工艺中的应用分析

文章介绍了自制高频感应电磁加热辊与传统导热油热辊在升温、保温、降温阶段能耗对比实验,结果表明:在相同测试条件下,高频感应电磁加热辊表面温度均匀性好,热效率高,节能降耗明显,为高频感应热辊在印染行业中的产业化应用提供参考。