Solar still with latent heat energy storage: A review

The requirement of fresh water is growing exponentially in industrial as well as domestic sector, resulting in more pollution of natural water resources and creating a scarcity of drinking water. Additionally, the number of arid and desert regions on the world map which already face the shortage of rainfalls and ground water. The problem is substantially increased as most of the water bodies like rivers, lakes are saline and brackish which are not suitable for drinking purpose. In recent past, solar desalination has been found to be a sustainable and economical way of generating the fresh water to cater the need of drinking water at large. Much technological advancement in the field of solar stills has been made which can ably produce a large quantity of fresh water depending on the availability of solar radiation. Various desalination schemes have been utilized to utilise water from such available resources to convert the available water in to the drinkable water. Additionally, attention has also been put on developing efficient solar still with latent heat based thermal energy storage systems which can work in the absence of sunlight as well. In the present paper, a short review on solar stills utilizing latent heat storage has been presented. The present study covers the design specifications, efficiency, along with the comparative analysis of solar stills with latent heat storage system, investigated in the last decade. A discussion on the future research outlook in the area of solar stills with latent heat storage has also been given, so as to make it more economically viable for generating sustainable potable water.     

热敏变色储能织物

采用热敏变色材料与储能材料复合,以制备热敏变色储能织物。研究了不同制备条件对涂层织物K/S值、变色性能以及服用性能的影响,结果显示,热敏变色材料的含量在1.5%～2%即可达到较好的变色效果;在应用方面,热敏变色材料与储能材料均匀混合后涂层较为适宜。当相变材料的添加量为10%、涂层浆料涂覆量为60 g/m2时,制备的热敏变色储能织物性能较好。扫描电镜图片和织物水洗测试显示,热敏变色材料和储能材料与织物的粘连很牢固,水洗对织物的储能性能和变色性能影响较小。     

氧化硅-脂肪醇复合溶胶制备蓄热调温织物

采用氧化硅-脂肪醇复合溶胶体系制备蓄热词温织物,分析了影响织物热性能的诸因素(如陈化时间、陈化温度、脂肪舫醇用量和分散剂用量等),并通过正交试验优化了整理工艺;对整理织物的表面形态进行表征,并测试了整理织物的热性能、机械强力和耐洗牢度等指标.结果表明,经氧化硅-脂肪醇复合溶胶整理后的织物,不但具有良好的蓄热调温性能,且耐洗牢度和机械性能都良好.     

大跨度主动蓄能型温室温湿环境监测及节能保温性能评价

针对日光温室土地利用率低,单体小不能进行立体栽培果树种植,不利于机械化操作等问题。该文提出一种大跨度主动蓄能型温室,该温室南北走向,双屋面拱形钢骨架结构,并采用主动蓄放热系统进行能量的蓄积与释放。该试验以传统砖墙日光温室作为对照,对大跨度主动蓄能型温室室内外温湿度以及主动蓄放热系统的能量收支进行分析,并对比2种温室的建造成本,综合分析了试验温室保温节能效果及经济效益。结果表明:大跨度主动蓄能型温室土地利用率高达87.4%。温室夜间平均气温高于10 ℃,无极端低温,晴天夜间平均气温比对照温室高1.5~3.1 ℃,比室外高13.9~19.3 ℃;阴天夜间平均气温比对照温室高1.2~2.8 ℃,比室外高12.5~18.9 ℃。夜间室内相对湿度平均比对照温室低7%~10%。主动蓄放热系统性能系数COP(coefficient of performance)为3.4~4.2,平均每天能耗0.013 kWh/m2,与传统燃煤锅炉加温系统相比,平均节能率为47%。大跨度主动蓄能型温室建造成本每平米307.2元,比传统砖墙日光温室低144.5元。大跨度主动蓄能型温室是一种土地利用率高,单体大,保温性能良好,能进行冬季果菜生产的新型温室类型,且投入少,综合其经济环境效益,值得推广应用。     

热处理与贮藏温度对草莓果实保鲜效果的影响

以大棚新鲜草莓为实验材料,分别研究2种热处理方式(40℃热空气,15min和40℃无菌水,15min)以及不同贮藏温度(常温20℃和低温4℃)对草莓的腐烂率、失重率的影响。结果表明,热处理明显有利于草莓的保鲜,其中热空气处理优于热水处理,低温贮藏优于常温贮藏。基于这一结论后,又以相同的新鲜草莓为实验材料,研究3种不同温度(35、40、45℃)的热空气和不同时间(10、15、20min)处理对草莓色泽、气味、硬度、酸度、糖含量以及呼吸强度的影响。结果表明,热处理能明显影响草莓贮藏期的生理和品质,热处理可保持草莓贮藏过程中的色泽、气味、硬度,降低其呼吸强度,减少草莓果实中糖和酸的损失,延缓草莓衰老。其中以45℃热空气处理10min保鲜效果最好。     

热处理结合柠檬酸处理对板栗贮藏效应的影响

将经过50℃,60min热处理的‘青扎’板栗浸渍于0.05%的柠檬酸中30min,样品均于0±1℃下冷藏,观察不同贮藏时期POD活性、淀粉酶活性、呼吸强度、腐烂率及失重率变化。结果表明,热处理结合柠檬酸处理显著降低了呼吸强度,抑制了淀粉酶活性、POD活性,腐烂率和失重率均低于单独使用热处理方法。     

可拆装PE-RT低温热管蓄冷装置及其使用碳氢制冷剂的蓄冷效果

基于热管技术,设计并制作了一套低成本、可快速拆装的PE-RT热管蓄冷装置,用高密度聚乙烯(PE-RT)导热塑料管替代紫铜管作为热管管材,用新型碳氢制冷剂HCR22作为热管循环工质,以蓄冷量为指标,研究了2种材质热管组在不同充液率和不同换热面积比时的蓄冷效果。试验结果表明:与同管径、同结构尺寸的铜质热管组相同,PE-RT热管组的最佳充液率也是33%,最佳充液时,PE-RT热管组的最优换热面积比同样是2.81;热管组蓄冷72h,PE-RT热管组和铜质热管组的储水槽水温分别降低13.52,15.30℃,PE-RT热管组的蓄冷量为铜质热管组的88.37%。该研究为PE-RT低温热管的推广和应用提供依据。     

短时升温在果实贮藏上的应用

温度是影响果实代谢过程、品质与贮藏寿命的重要因子,应用短时升温处理技术延缓果实衰老和控制采后病害是近年来果实保鲜领域的研究热点。本文归纳了短时升温在果实贮藏上的应用,热处理方法及常见果品短时升温最佳处理温度、时间。     

海藻酸钠-壳聚糖相变储热微胶囊的制备

海藻酸钠和壳聚糖都是价廉环保的天然高分子材料,具有广阔的应用开发前景。以海藻酸钠-壳聚糖为壁材,复合醇为芯材,通过乳化固化法制备出相变储热微胶囊,解决了脂肪醇在相变过程中的泄露问题。探讨了芯材用量、碳酸钙用量、乳化体系和壳聚糖浓度等对微胶囊储热性能的影响,利用扫描电镜、激光粒径分析仪、DSC和测试步冷曲线等手段对微胶囊进行表征。结果表明,制得微胶囊的相变温度为37.9℃,调温区间为37.9~40.8℃,相变潜热为52.8J/g,芯材包封率为44.7%。     

Quality of shell eggs pasteurized with heat or heat-ozone combination during extended storage

The physical quality and functionality of shell eggs, pasteurized with heat or a combination of heat and ozone, were assessed during eight weeks of storage at 4 or 25 °C. Shell eggs were treated as follows: (1) immersion heating that mimics commercial pasteurization processes (egg internal temperature of 56 ± 0.1 °C for 32 min), or (2) a newly developed combination process comprised of heating (56 ± 0.1 °C, internal, for 10 min) followed by gaseous ozone treatment. Eggs were tested for yolk index, Haugh units, albumen pH, albumen turbidity, and percent overrun. Additionally, albumen samples were assayed for lysozyme activity and free sulfhydryl group content, and were analyzed using differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. Both processed and unprocessed eggs maintained superior quality when stored at 4 °C, as opposed to 25 °C. Pasteurization, regardless of method, led to superior maintenance of Haugh units during storage but also increased albumen opacity and decreased albumen overrun. Detrimental effects on quality markers were more severe in heat-pasteurized eggs than those treated with the ozone-based process. Pasteurization of shell eggs by either process did not affect lysozyme activity or sulfhydryl group content. Changes in protein secondary structure, as indicated by FTIR analysis, suggest that the ozone-based process is less damaging to albumen proteins than is the heat-alone process. In conclusion, heat-ozone pasteurization, by virtue of its less severe heat treatment, yields a safe final product that more closely resembles untreated shell eggs.     

热处理对鲜切苹果的保鲜效果

为研究热处理对鲜切苹果品质的影响,将鲜切寒富苹果分别放入50、60、70℃的热水中浸泡2 min后沥干、用0.11 mm厚度的PE保鲜膜包装后置于4℃冷库中贮藏,每2d测定与成熟衰老相关生理生化指标。结果表明,适当的热处理可保持苹果切片的感官品质、延缓营养物质的下降、抑制微生物的繁殖,对鲜切苹果有较好的护色效果;50℃热水浸泡处理能在8d贮藏期内4℃冷库中维持鲜切苹果较好的品质。     

聚氨酯涂层剂对热敏变色储能织物性能的影响

采用传统的涂层工艺,将水性聚氨酯和溶剂型聚氨酯涂层剂整理到自制的热敏变色储能材料织物中;分析与比较了涂层织物的外观形貌、变色效果、储能效果等性能。扫描电镜结果显示,两种聚氨酯涂层剂在织物表面都能形成均匀平滑的涂层,溶剂型聚氨酯涂层更加致密,而水性聚氨酯涂层表面存在微小孔隙,更加透气。涂层整理织物的DSC测试结果显示,水性涂层织物的储能性能更加良好,其起始相变温度为33.9 ℃,终止相变温度为37.9 ℃,潜热值达到38.84 J/g,调热值达到4 466.6 J/m2。各项指标显示,水性聚氨酯涂层织物具有更好的性能。     

不同湿度对热处理西葫芦传热过程及低温贮藏品质和抗氧化系统的影响

该文研究了采后西葫芦果实分别经不同湿度(40％、60％、80％、90％)的热空气处理(44℃、2.3 h)后在(4±0.5)℃湿度(80±5)％的低温条件下对果实的品质以及抗氧化系统的影响,测定失重率,冷害指数,电解质外渗率,抗坏血酸含量,过氧化氢酶活性等指标,并对不同湿度热空气处理过程进行传热分析.结果表明,80％湿...     

Solar dryer analysis and effectiveness under four seasons with sensible and latent heat storage units

Morocco has considerable solar potential during most of the year, making solar drying one of the most effective methods. Therefore, in this paper, we evaluated a solar dryer under four seasons based on the real meteorological conditions of eastern Morocco. Besides, we have studied the integration of two different storage units based on latent and sensible heat presented by PCM tubes and a packed bed of pebbles, respectively. The main idea is to test the ability of these units in the four seasons to determine the suitable one. The numerical studies were made using the CFD method and the weather files were integrated into the software in form of subroutines written in C++. The obtained results showed that a storage unit is useless in winter, but a solar dryer can be used to dry low-moisture products like plants as the temperature is higher than the ambient one with 21.75° as a maximum. In spring and summer, the storage unit is found to be effective. However, for a low-moisture product, the packed bed is recommended. In the opposite case, the PCM is better as its effect stays the whole night. In autumn, both storage units are not so recommended as the released heat is not high. The efficiencies of the three solar dryer cases in four seasons were also analysed, and we found that it reaches 80% and 65% in summer in the packed bed and PCM case respectively, where the PCM case provides almost a uniform dryer efficiency throughout the whole day.     

相变储能材料在立筒仓稻谷控温储藏中的应用研究

针对夏季粮仓温度高,表层易发热从而引起粮食品质劣变的现象,开展了利用相变储能材料的准低温稻谷储藏实仓试验。分别选择29号常规储粮仓、保温处理后的30号储粮仓和使用相变储能材料的31号储粮仓进行储粮效果对比实验。在测试期间,随着外温的变化,通过对29号、30号、31号三个立筒仓仓温和表面粮温的测定,结果表明:使用相变储能材料的31号粮仓仓温和粮温最低,且随着外温的变化表层粮温几乎不变,该粮仓能有效控制粮仓温度和表层粮温,实现准低温储粮。     

Improved accounting of emissions from utility energy storage system operation

Several proposed utility-scale energy storage systems in the U.S. will use the spare output capacity of existing electric power systems to create the equivalent of new load-following plants that can rapidly respond to fluctuations in electricity demand and increase the flexibility of baseload generators. New energy storage systems using additional generation from existing plants can directly compete with new traditional sources of load-following and peaking electricity, yet this application of energy storage is not required to meet many of the Clean Air Act standards required of new electricity generators (e.g., coal- or gas-fired power plants). This study evaluates the total emissions that will likely result from the operation of a new energy storage facility when coupled with an average existing U.S. coal-fired power plant and estimates that the emission rates of SO2 and NOx will be considerably higher than the rate of a new plant meeting Clean Air Act standards, even accounting for the efficiency benefits of energy storage. This study suggests that improved emissions "accounting" might be necessary to provide accurate environmental comparisons between energy storage and more traditional sources of electricity generation.     

Capacitive bioanodes enable renewable energy storage in microbial fuel cells

We developed an integrated system for storage of renewable electricity in a microbial fuel cell (MFC). The system contained a capacitive electrode that was inserted into the anodic compartment of an MFC to form a capacitive bioanode. This capacitive bioanode was compared with a noncapacitive bioanode on the basis of performance and storage capacity. The performance and storage capacity were investigated during polarization curves and charge-discharge experiments. During polarization curves the capacitive electrode reached a maximum current density of 1.02 ± 0.04 A/m(2), whereas the noncapacitive electrode reached a current density output of only 0.79 ± 0.03 A/m(2). During the charge-discharge experiment with 5 min of charging and 20 min of discharging, the capacitive electrode was able to store a total of 22,831 C/m(2), whereas the noncapacitive electrode was only able to store 12,195 C/m(2). Regarding the charge recovery of each electrode, the capacitive electrode was able to recover 52.9% more charge during each charge-discharge experiment compared with the noncapacitive electrode. The capacitive electrode outperformed the noncapacitive electrode throughout each charge-discharge experiment. With a capacitive electrode it is possible to use the MFC simultaneously for production and storage of renewable electricity.