Performance on Power,Hot and Cold Water Generation of a Hybrid Photovoltaic Thermal Module

This paper proposed a new function of photovoltaic thermal(PVT)module to produce nocturnal cool water not just only generating electrical power and hot water during daytime.Experimental tests were carried out under Chiang Mai tropical climate with a 200 Wp monocrystalline PVT module having dimensions of 1.601 m×0.828 m connected with two water tanks each of 60 L taken for hot and cool water storages.The module was facing south with 18o inclination.The electrical load was a 200 W halogen lamp.From experiments,by taking the module as a nocturnal radiative cooling surface,the cool water temperature in the cool storage tank could be reduced 2℃–3℃each night and the temperature could be reduced from 31.5℃to 22.1℃within 4 consecutive days.The cool water at approximately 23℃was also used to cool down the PVT module from noon when the PVT module temperature was rather high,and then the module temperature immediately dropped around 5℃and approximately 10%increase of electrical power could be achieved.A set of mathematical models was also developed to predict the PVT module temperature and the hot water temperature including the cool water temperature in the storage tanks during daytime and nighttime.The simulated results agreed well with the experimental data.

Evaluation of Pencil Lead Based Electrodes for Electrocardiogram Monitoring in Hot Spring

Electrocardiogram(ECG)electrodes are conductive pads applied to the skin to measure cardiac activity.Ag/AgCl electrodes are the commercial product which widely used to obtain ECGs.When monitoring the ECG in a hot spring,Ag/AgCl electrodes must be waterproofed;however,this is time-consuming,and the adhesive may tear the skin on removal.For solving the problem,we developed the carbon pencil lead(CPL)electrodes for use in hot springs.Both CPL and Ag/AgCl electrodes were connected to ECG100C’s cables.The Performance was evaluated in three conditions as following:hot spring water with and without bubble,and in cold water.In each environment,the procedure was followed by three different protocols that are recording from the dry condition,hot spring water immersion with and without movement,post hot spring water condition.Under dry and wet conditions,both electrodes can obtain the waveform of the ECG signal in which all PQRST waves were identifiable.Nevertheless,the signal quality of both types of electrodes was different in water immersion with and without movement.The overall morphology obtained by Ag/AgCl electrodes was unstable higher than that of CPL electrodes in immersion without movement condition.The CPL electrodes provided better ECG waveform quality compared to Ag/AgCl electrodes in which the ECG signal had high waveforms distortion in water immersion with movement condition.

Identifying hot spots of long-duration extreme climate events in the northwest arid region of China and implications for glaciers and runoff

China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities.Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold,warm,dry and wet days in the NAR based on China’s 0.5°×0.5°meteorological grid datasets of daily temperature and precipitation from 1961 to 2018.This study found that(1)the consecutive cold days(Cold Spell Duration Indicator,CSDI),and the consecutive dry days(CDD)decreased,while the consecutive warm days(Warm Spell Duration Indicator,WSDI),and the consecutive wet days(CWD)increased from 1961 to 2018,(2)and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly,(3)and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index.The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961–2018 in the NAR under the global warming,which can lead to the sustained glacier retreat and the increase in summer runoff in this region,and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future.Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods,it is most crucial to improve the strategies of water resources management,disaster prevention and risk management for this region under climate change.

Water resource utilization characteristics and driving factors in the Hainan Island

The scarcity of water resources caused by the unique topography and uneven rainfall distribution in Hainan Island has become a major factor restricting local development. In order to provide effective and scientific reference basis for the overall water resource utilization status and solving this problem, this study calculated the water resource utilization situation of Hainan Island from 2017 to 2021 in detail using methods including water resource ecological footprint analysis. Furthermore, a spatial correlation analysis was conducted to examine the island's water resource utilization characteristics, and the driving factors behind the changes in water resource utilization over the past five years were analyzed using the LMDI model. The results show that:(1) During the study period, the water resource ecological footprint in Hainan Island exhibited a slow growth trend, while the ecological carrying capacity showed a downward tendency.The per capita ecological deficit of water resources remains relatively high, and the water consumption per 10 000 yuan GDP in the whole land continues to decrease, indicating that the overall pressure on water resource demand remains high with significant regional differences accompanied by the efficiency of water resource utilization steadily improving at the same time;(2) Agricultural water use accounts for the highest proportion in the entire water use structure, while ecological water use represents the smallest share, with a year-on-year increase, indicating that Hainan Island highlights the agricultural development and is increasingly conscious of the ecological environment;(3) Significant spatial differentiation in water resource utilization characteristics exists in Hainan Island, with the western region being a hot spot aggregation area for per capita water resource ecological footprint, per capita ecological carrying capacity of water resources, water consumption per 10 000 yuan GDP, while it is a cold spot cluster area for per capita ecological deficit of water resources. The opposite holds true for the eastern region of Hainan Island;(4) Economic and technological factors have a major impact on the changes in water resource ecological footprint within the designated area. Among them, economic factors drive the growth of the water resource ecological footprint in Hainan Island, and exacerbate local water resource consumption, while technological factors negatively contribute to the amount of water resource utilization in Hainan Island, indicating that advanced technology has improved water resource utilization efficiency and significantly reduced water resource consumption.

夏热冬冷地区住宅浴室热湿环境与洗浴行为研究

对上海地区住宅浴室热湿环境进行了实地测量,分析了浴室热湿环境特征,并通过网络问卷调研了典型人群的洗浴行为。结果表明:浴室热湿环境受洗浴行为影响明显,淋浴开始后空气温度迅速升高,相对湿度接近饱和状态,淋浴结束后相对湿度需要较长时间才能恢复至初始状态,与常规居家场景相比,洗浴过程中的浴室热湿环境偏离常规热舒适区;夏热冬冷地区居民洗浴行为受季节影响明显,淋浴水温冬季偏暖(43.3℃左右)、夏季偏凉(一般36~40℃);洗浴频次以1天1次或2天1次为主;洗浴时长夏季多为5~10 min、冬季多为10~20 min。本文还探讨了浴室环境改善措施和浴室热舒适的特殊性。

液态CO_(2)-水蒸气循环冲击煤体增透及瓦斯抽采效果模拟

【目的】为解决液态CO_(2)煤层增透技术应用时煤层内部孔隙水受冷凝结为冰阻塞瓦斯运移通道这一问题,提出液态CO_(2)-高温水蒸气冷热循环冲击煤体增透技术。【方法】利用低场核磁共振仪、煤岩渗透率自动测试仪、接触角测试仪和三维CT扫描仪分析液态CO_(2)-高温水蒸气冷热循环冲击煤体渗透率演化规律。【结果和结论】结果表明:(1)液态CO_(2)-高温水蒸气冷热循环冲击煤体T2曲线面积随冷热循环冲击次数增加而增加。(2)煤体渗透率增量与液态CO_(2)-高温水蒸气冷热循环冲击次数指数相关,循环冲击次数增加,煤体渗透性和润湿性均增强。(3)液态CO_(2)-高温水蒸气冷热循环冲击次数达到12次时,渗流孔体积比例增加23.57%,渗透率增加0.009 3×10^(-3)μm^(2),接触角减小39.45°。(4)煤体渗透性与渗流孔体积比例、接触角相关,渗流孔体积比例与煤体渗透率正相关,接触角与煤体渗透率指数相关。基于实验研究结果,利用COMSOL软件数值模拟低温液态CO_(2)-高温水蒸气冷热循环冲击煤层工程现场应用。依据试验结果确定恢复到室温25℃时的有效作用半径为0.719 8 m,以此数据模拟矿井煤层瓦斯抽采,结果显示煤层温度与瓦斯抽采效率成正比。试验及模拟结果揭示了液态CO_(2)-高温水蒸气冷热循环冲击煤体增透技术的现场钻孔布置及瓦斯抽采运移规律,为该技术下一步现场应用提供参考。

胶合板用高温花生粕和低温花生粕蛋白基胶黏剂的制备与表征

[目的]以高温花生粕(HPM)和低温花生粕(CPM)为试验原料,通过变性交联提高胶黏剂的胶接性能和耐水性,为花生粕蛋白基胶黏剂的进一步实际应用提供参考。[方法]采用尿素(U)变性和聚酰胺多胺环氧氯丙烷(PAE)树脂交联两步法制备HPM和CPM蛋白基胶黏剂,并比较其在胶合强度、黏度、官能团、热性能和微观形貌方面的差异。[结果]与未变性交联的HPM和CPM胶黏剂相比,变性交联后HPM和CPM胶黏剂制备的杨木胶合板干态胶合强度分别提高134.1%和111.4%,湿态胶合强度分别满足国家标准Ⅰ类和Ⅱ类胶合板要求;变性交联后HPM与CPM胶黏剂黏度分别提高101.5%和70.5%,热分解温度分别提高至316.44和307.57℃,且HPM制备的胶黏剂表面最紧密。[结论]变性交联后HPM胶黏剂的胶合强度、耐水性优于CPM胶黏剂,HPM比CPM更适宜作胶黏剂原料。

夏热冬冷地区空调冷热源配置的多目标优化

为实现“双碳”背景下清零建筑直接碳排放的目标,夏热冬冷地区建筑空调冷热源越来越多地采用空气源热泵加水冷式冷水机组的复合架构。其中,空气源热泵冬季供热,夏季与水冷式机组共同供冷。由于空气源热泵供冷能效较低,提高水冷式机组容量配置,尽可能使之分担更多的冷负荷,有利于降低系统供冷能耗,但系统投资也将随之上升。因此,有必要研究复合架构下空调冷热源配置的综合优化方法。利用层次分析法,计算空调冷热源系统的节能性、环保性、经济性、节材性等不同目标维度的权重,建立空调冷热源的综合优化目标函数。设计空调冷热源配置的优化流程,并以上海某办公建筑为例进行分析。结果表明,随着水冷机组容量的增加,空调冷热源系统的全年能耗降低,耗材生产能耗、折算年费上升,而碳排放呈先降后升的规律。多目标优化方法可以更好地实现各项指标之间的平衡,为相关研究及实际项目决策提供参考。

延庆赛区冬奥村运动员居住组团的热水设计探讨

集中热水系统在现代酒店、公寓等公共居住建筑内已经普遍使用,但由于设计的缺陷或施工时的错误导致热水水质不达标、冷热不均、支管过长以致水资源浪费等多种问题在热水系统运行过程中越来越显著,根据延庆冬奥村某运动员组团的热水系统设计经验,阐述设计过程中所遇到的关于热水系统的平衡问题,为日后热水系统的设计、施工、运行提供参考。由于图纸设计完成时间在2018-2019年间,现行国家标准《建筑给排水设计标准》(GB 50015-2019)于2020年实施,在撰写过程中重新梳理了新版标准中与当时设计过程中执行的《建筑给排水设计规范》(GB 50015-2003,2009年版)要点。

冷库冷风机融霜方式对比分析

阐述用于冷库冷风机融霜的热气融霜、水冲霜、电热融霜的工作原理,在相同运行工况下,从初投资、运行成本、融霜效果等方面进行对比分析。结果表明,电热融霜冷风机初投资最低,约为热气融霜的60%,水冲霜的80%;热气融霜冷风机运行成本约为电热融霜冷风机的40%~50%,水冲霜冷风机的1.2~1.4倍;水冲霜融霜效果最好。最后针对不同类型冷库冷风机给出融霜方式的建议。

广州某大型医院冷热源方案选型及水系统设计分析

介绍了广州市某大型综合医院空调系统设计,基于对综合医院所处位置及实际需求的深入分析,探讨非净化区与净化区空调冷热源系统的方案选型。另外,通过一级泵变流量系统与二级泵变流量系统方案的对比,根据实际情况探索该大型医疗综合楼空调水系统的最佳方案。

夏热冬冷地区空气源热泵供暖结霜规律研究

基于“双碳”目标,我国各领域电能替代工作取得了蓬勃发展。在建筑领域,目前我国正在大力推广空气源热泵供暖技术,为了探究其电力替代可行性,基于空气源热泵结霜机理,提出了一种基于气象参数及水相图的结霜理论判断方法,并选取夏热冬冷地区10个典型城市进行了空气源热泵供暖结霜规律分析。结果表明,夏热冬冷地区整体较适合开展空气源热泵供暖,但工程实践中应结合不同城市结霜规律针对性制定除霜控制策略。此外,提出的空气源热泵结霜判断方法相较于传统研究具有一定优势,可有效避免热泵机组结霜时长被低估等问题。该理论方法为解决夏热冬冷地区“双碳”目标与健康舒适人居所面临的挑战提供了有力支撑。

基于不带回水管的零冷水节能方案研究

随着社会科技的不断进步,人们对生活质量的要求也越来越高,但高质量的生活需求往往伴随着更高能源的消耗;环境变化对生活的影响越来越大,人们现对保护环境的意识也是越来越强,我们在享受科技进步所带来的高质量生活体验的同时,还应该加强对环境的保护,加强节约能源;为了实现节能高效,为了提升零冷水在使用过程低碳排放,我们对不带回水管的零冷水技术深入研究,通过重新分配管路热水的方法,实现满足生活热水使用同时也节能环保。

不同发酵条件对饲料固态发酵效果的影响

[目的]为研究不同发酵环境下饲料固态发酵效果的影响,优化发酵饲料固态发酵工艺。[方法]试验在室温10℃以下(平均室温5℃)分为温水启动发酵和冷水启动发酵2个组别,每个组别各2个重复;同时以常规标准发酵方法(在发酵房温度恒温30℃发酵7 d后转入室温)作为对照组。分别检测料温、水分、pH、乳酸、乙醇、活菌数及感官观察等。[结果]发酵15 d时,对照组的水分绝对增长值明显高于其他3组,温水发酵的提高2.06百分点;对照组的pH已降到5.48,温水发酵包内的pH为5.92,其他3组的均在6.1以上;对照组的乳酸含量为9.48 g/kg,其他3组的均低于2.5 g/kg。[结论]在低温情况下,温水启动发酵明显优于冷水启动发酵;无论是温水启动发酵还是冷水启动发酵,即使延长发酵时间,也无法达到设定出库标准。

以再生水为热源的热、冷、水同输联供系统应用前景分析

为应对水污染及水资源缺乏问题,响应国家低碳、环保、节能、减排、综合高效等能源政策,提高再生水循环利用率及可再生能源在供热(冷)领域的利用率,利用再生水水质较好,水温、水量相对稳定的特点,将再生水厂作为综合能源站,通过预制保温层球墨铸铁管等新型管材输送至城市用热(冷)负荷末端。经分布式热泵机组取热(冷)后,再生水水质和水量基本不变,可进一步作为城市景观用水、工业用水等;水热冷同输联供系统利用长输管网输送,可实现再生水、热(冷)单管同输,投资降低,节能运行;分布式热泵机组根据末端负荷需求一机多用、高效节能,经济运行;换热后的再生水可再利用,增加再生水资源综合利用率。水热冷同输联供系统实现了再生水的高效综合利用,同时供热、供冷和供再生水,提高了能源的综合效益,打破了常规行业壁垒,具有一定的推广意义。

空气源热泵在寒冷地区水稻芽种生产系统中的应用

热泵作为一种节能环保技术受到了世界各国的普遍重视,而空气源热泵可从大气中吸取丰富的低位能量,使用安装方便,运转费用较低,因此得以广泛推广应用。但是,普通空气源热泵的应用范围受到气候条件的约束,随着大气温度的降低,普通空气源热泵的制热量逐渐减少,不能满足用户对制热量的需求。当室外气温很低时,随着压缩机压缩比的不断增加,其COP急剧下降,排气温度迅速升高,从而导致压缩机不能正常运行甚至损坏。由于喷气增焓技术和高效过冷却等技术的应用,使得低温型空气源热泵得以在-15～-25℃的环境温度下应用,也使得空气源热泵在寒冷地区水稻芽种生产系统中的应用成为现实。

皂荚豆胶冷水溶部分和热水溶部分的流变性研究

本研究对皂荚豆胶冷水溶和热水溶部分的流变性进行了研究。研究结果表明:浓度、温度、剪切力、pH值、冻融等变化对皂荚豆胶的粘度有较大影响;皂荚豆胶与黄原胶、卡拉胶具有明显的协效性;皂荚豆胶在冷水和热水中溶解,其流变性有所不同。

高性能重组木制造工艺对其性能的影响

采用冷、热压两种生产工艺,分别制备不同密度的高性能重组木产品,并检测其物理力学性能。结果表明:两种生产工艺均可以制备出物理力学性能优良的高性能重组木,其中冷压-热固化法生产的重组木耐水性能良好;热压法生产的重组木的抗弯性能和抗剪性能更优。

制造工艺对竹基纤维复合材料性能的影响

采用冷、热压两种生产工艺,分别制备不同密度(0.85～1.20g/cm3)的竹基纤维复合材料,并检测其物理力学性能。结果表明:两种生产工艺均可制备出物理力学性能优良的竹基纤维复合材料,其中:冷压生产的竹基纤维复合材料的耐水性能较好,热压生产的竹基纤维复合材料的抗弯性能和抗剪切性能更优。

不同处理对无花果保鲜效果的研究

[目的]寻找绿色、实用及廉价的无花果鲜果贮藏途径。[方法]以新鲜无花果为供试材料,分别采用热水处理、冷激处理及大蒜提取液处理等方法,研究其在4℃条件下的保鲜效果。[结果]各处理均能抑制无花果腐烂指数和丙二醛(MDA)含量的上升,延缓果实的可溶性固形物、可滴定酸及维生素C含量的下降。其中冷激处理1.5 h的保鲜效果明显优于其他各组处理。[结论]在不影响无花果果实品质的前提下,冷激处理1.5 h的保鲜效果最好,操作简便,是一种理想的无花果保鲜处理方法。