Performance comparison of solar still with inbuilt condenser and agitator over conventional solar still with energy and exergy analysis

Environmental Science and Pollution Research - Demand for fresh water increases day by day. Solar desalination is one of the promising technologies to meet this demand in an economical fashion...     

Productivity enhancement of solar still through heat transfer enhancement techniques in latent heat storage system: a review

Environmental Science and Pollution Research - Solar still is one of the sustainable and renewable technology which converts brackish or salty water into fresh water. The technology helps in CO2...     

Performance assessment of single slope solar still by the incorporation of palm flower powder and micro phase change material for the augmentation of productivity

Water scarcity necessitates a cost-effective and productive solution. This study focused to enhance the productivity of single slope solar still by incorporating the better weight of palm flower powder (micro-sized) in the basin and micro phase change material heat storage bed under the basin. In this aspect, the different quantity of palm powder weights such as 10, 30, 50, 70, 100, 120 and 150 g in the basin was experimentally examined. The absorber basin containing 50 g of palm powder has better productivity of 37.25%, whereas for 10, 30, 70, 100, 120 and 150 g, they were 11.85, 24.78, 36.8, 33.05, 10.25 and ? 20.22% respectively. The influence of palm powder with different weight% impregnated in the paraffin wax was analysed. The maximum thermal conductivity of 0.33 W/m K was obtained in the sample containing palm flower powder of 20 wt%. The experimental investigation was carried out with 50 g of micro-sized palm powder in the basin and thermal storage bed under the basin containing 20 wt% of micro phase change material (PCMPFP-SS) and conventional solar still (CSS). The overall distillate output of PCMPFP-SS was 4670 and 4250 mL/m² on day 1 and day 2 respectively. On the other hand, the overall distillate output for CSS was 3030 and 2800 mL/m² on day 1 and day 2. From the economic analysis, it was found that the cost per litre (CPL) of PCMPFP-SS and CSS was $ 0.025 and $ 0.032 respectively. Moreover, the payback period of PCMPFP-SS was lowered from 5.1 to 4.1 months compared to CSS.

     

Investigation of performance enhancement of solar still incorporated with Gallus gallus domesticus cascara as sensible heat storage material

In this research work, the conventional single slope still (CSS) with egg shells of breed Gallus gallus domesticus cascara as sensible heat storage (SHS) material are studied experimentally to enhance the yield. In this experimental investigation, the proposed single slope still (PSS) with SHS material was made in comparison with the CSS to evaluate the productivity of fresh water under the same ambient conditions. Comparatively, this PSS has higher thermal conductivity than the CSS. The yield obtained from the PSS is 2.46 L/m², while the yield from the CSS is 2.07 L/m². The average rate at which the rise of output fresh water obtained from the PSS is 18% more than the fresh water output obtained from the CSS. The daily energy efficiency of the PSS is 26.07%, and for the CSS, it is only 22.25%. The daily exergy efficiency of the PSS is 2.36%, and for the CSS, it is only 1.67%. Since using the egg shell will employ as organic waste management and modification in this still is economical, less initial, and maintenance cost.

     

Performance enhancement of single-slope solar still using phase change materials

Environmental Science and Pollution Research - Freshwater scarcity appears clearly in coastal areas of Egypt despite the existence of a large amount of seawater around. Solar still is the cheapest...     

Design,fabrication and performance assessment of a solar cooker with optimum composition of heat storage materials

Environmental Science and Pollution Research - Solar energy as an inexhaustible source of energy has been the primary interest of many researchers for the last four to five decades due to its wide...     

Performance improvement of modified tubular solar still by employing vertical and inclined pin fins and external condenser: an experimental study

Environmental Science and Pollution Research - The current experimental work aims to improve an accumulative yield of tubular solar distillers. This was achieved by utilizing the pin fins and...     

Energy,exergy, and economic analysis of solar still using coal cylinder fins: an experimental study

Environmental Science and Pollution Research - The phenomenon of drinking water scarcity has turned into the foremost issue that the world’s populace is facing today. The Algerian desert...     

Exergy and energy analysis of a tubular solar still with and without fins: a comparative theoretical and experimental approach

Environmental Science and Pollution Research - One of the major challenges faced by human society is the freshwater crisis and shortage of conventional energy. Solar still is considered as one of...     

Factors affecting the performance of a solar still and productivity enhancement methods: A review

Environmental Science and Pollution Research - Good-quality drinking water is an essential requirement for a healthy and sustainable future. In the current scenario, people living in remote areas...     

Analysis of a solar still with photovoltaic modules and electrical heater - Energy and exergy approach

The availability of drinkable water, along with food and air, is a fundamental human necessity. Because of the presence of higher amounts of salt and pollution, direct use of water from sources such as lakes, sea, rivers, and subsurface water reservoirs is not normally suggested. Solar is still a basic technology that can use solar energy to transform accessible waste or brackish water into drinkable water. Exergy analysis is a strong inferential technique for evaluating the performance of thermal systems. Exergy is becoming more popular as a predictive tool for analysis, and there is a rising interest in using it. In this paper, performance analysis on the aspect of energy and exergy from the proposed solar still (PSS) (conventional solar still with the photovoltaic modules-AC heater) was analyzed on three different water depths (W_d) conditions (1, 2, and 3 cm). Using a solar still with an electric heater, the daily potable water production was found as 8.54, 6.37, and 4.43 kg, for the variations in water depth (W_d) of 1, 2, and 3 cm respectively. The energy and exergy efficiency of the PSS at the W_d of 1, 2, and 3 cm were 75.67, 51.45, and 37.21% and 5.08, 2.29, and 1.03%, respectively. At 1 cm W_d, PSS produced the maximum freshwater yield as compared to the other two water depths. When the W_d is increased from 1 to 2 cm and from 1 to 3 cm, the yield is decreased up to 27.3 and 52.7%, respectively. Similarly, the energy and exergy efficiency is decreased up to 36.8 and 53.2% and 50.4 and 80.6%, respectively. The water cost of the modified solar still is calculated as 0.028 $/kg for the least water thickness.

     

Enhancement of the daily performance of solar still by exhaust gases under hot and cold climate conditions

Environmental Science and Pollution Research - A study is presented on the enhancement of solar still (SS) performance by using chimney exhaust gases (EGs) passing through chimney channels under...     

Extent of intracellular storage in single and dual substrate systems under pulse feeding

The study investigated the effect of acetate/starch mixture on the formation of storage biopolymers as compared with the storage mechanism in systems fed with these compounds as single substrates. Experiments involved two sequencing batch reactor sets operated at steady state, at sludge ages of 8 and 2 days, respectively. Each set included three different runs, one fed with acetate, the other with starch and the last one with the acetate/starch mixture. In single substrate systems with pulse feeding, starch was fully converted to glycogen, whereas 25 % of acetate was utilized for direct microbial growth at sludge age of 8 days, together with polyhydroxybutyric acid (PHB) storage. The lower sludge age slightly increased this fraction to 30 %. Feeding of acetate/starch mixture induced a significant increase in acetate utilization for direct microbial growth; acetate fraction converted to PHB dropped down to 58 and 50 % at sludge ages of 8 and 2 days respectively, while starch remained fully converted to glycogen for both operating conditions. Parallel microbiological analyses based on FISH methodology confirmed that the biomass acclimated to the substrate mixture sustained microbial fractions capable of performing both glycogen and PHB storage.     

Performance improvement and advancement studies of mixed-mode solar thermal dryers: a review

Solar thermal dryers are solar-operated gadgets utilized to dehumidify various products, especially food items and rubber sheets. This article provides detailed design, parametric studies, and an in-depth review of mixed-mode solar dryers (MMSD) with a case study of fish drying near coastal lines. Due to several advantages compared to open sun drying and prominent performance index compared to indirect and direct type solar dryers, mixed-mode solar dryers have large adaptability on the field. Moreover, mixed-mode solar thermal dryers with different augmentations are reviewed, for instance, mixed-mode solar dryers with evacuated tube collectors, phase change materials, ultraviolet rays stabilized housing, and dehumidifiers. The case study of fish drying near the coastal line of Gujarat, India has been carried out to study the present scenario of the drying activities. Hence, the objective of this review is to identify the capable mixed-mode solar dryer with heat recovery systems. Substantial reviews within the article suggest an essential need to implement the hybrid mixed-mode solar dryer cum distiller technology for small-scale enterprises that can simultaneously provide potable water near coastal lines along with drying of fishes from the solar dryer. Furthermore, future research demands such hybrid mixed-mode solar drying systems that strongly fulfill the requirements of local communities near coastal lines involved in fish drying activities.

     

Effects of soiling and cleaning on the reflectance and solar heat gain of a light-colored roofing membrane

A roof with high solar reflectance and high thermal emittance (e.g., a white roof) stays cool in the sun, reducing cooling power demand in a conditioned building and increasing summertime comfort in an unconditioned building. The high initial solar reflectance of a white membrane roof (circa 0.8) can be lowered by deposition of soot, dust, and/or biomass (e.g., fungi or algae) to about 0.6; degraded solar reflectances range from 0.3 to 0.8, depending on exposure. We investigate the effects of soiling and cleaning on the solar spectral reflectances and solar absorptances of 15 initially white or light-gray polyvinyl chloride membrane samples taken from roofs across the United States. Black carbon and organic carbon were the two identifiable strongly absorbing contaminants on the membranes. Wiping was effective at removing black carbon, and less so at removing organic carbon. Rinsing and/or washing removed nearly all of the remaining soil layer, with the exception of (a) thin layers of organic carbon and (b) isolated dark spots of biomass. Bleach was required to clear these last two features. At the most soiled location on each membrane, the ratio of solar reflectance to unsoiled solar reflectance (a measure of cleanliness) ranged from 0.41 to 0.89 for the soiled samples; 0.53 to 0.95 for the wiped samples; 0.74 to 0.98 for the rinsed samples; 0.79 to 1.00 for the washed samples; and 0.94 to 1.02 for the bleached samples. However, the influences of membrane soiling and cleaning on roof heat gain are better gauged by fractional variations in solar absorptance. Solar absorptance ratios (indicating solar heat gain relative to that of an unsoiled membrane) ranged from 1.4 to 3.5 for the soiled samples; 1.1 to 3.1 for the wiped samples; 1.0 to 2.0 for the rinsed samples; 1.0 to 1.9 for the washed samples; and 0.9 to 1.3 for the bleached samples.     

Performance analysis of sustainable solar energy operated ejector refrigeration system with the combined effect of Scheffler and parabolic trough collectors to lower greenhouse gases

Environmental Science and Pollution Research - The work aims to analyse an ejector refrigeration system powered with solar energy through serially connected collectors to lower greenhouse gases....     

Performance analysis of photovoltaic-thermal air collectors combined with a water to air heat exchanger for renewed air conditioning in building

Environmental Science and Pollution Research - In this work, a new solar system that includes photovoltaic-thermal (PVT) air collectors coupled to a water-to-air heat exchanger is investigated. The...     

城市生物质废物厌氧消化前后粒径分布特征解析

在稳定运行的城市生物质废物厌氧消化中试研究结果基础上,对基质及消化液的有机物粒径分布特征进行解析。在反应器有机负荷为2.4、6.0和8.0 kg VS/(m3·d),停留时间为50、20和15 d 3个状态下,反应器对城市生物质废物有良好的去除效果,VS去除率均在60%以上。其中粒径96μm的大颗粒有机物去除率均在80%以上,负荷及停留时间对大颗粒有机物的去除效果没有表现出明显影响;随着负荷的增加及停留时间的缩短,消化液中粒径范围0.45~74μm的有机物及溶解性有机物的含量增加,去除率降低;研究结果表明,在传统的厌氧消化条件下,对于本研究中的城市生物质废物而言有机物的酶解过程是主要限速步骤。     

长株潭区域生物质开放燃烧的大气污染物排放清单及不确定性分析

根据2012年长株潭区域生物质产量及露天焚烧数据,结合排放因子,估算了长株潭区域生物质开放燃烧所排放的大气污染物量,建立了2012年长株潭区域生物质开放燃烧大气污染物排放清单。结果表明,2012年长株潭区域生物质开放燃烧源SO_2、NO_X、PM_(10)、PM_(2.5)、挥发性有机物(VOCs)、CO、元素碳(EC)、有机碳(OC)排放量分别为783.48、4 248.00、10 325.94、10 117.29、6 882.92、76 002.99、816.09、3 478.28t。秸秆露天焚烧大气污染物排放量在7、10月形成2个峰值,森林火灾集中出现在夏、秋季。生物质开放燃烧污染物排放量最大的县区为长沙市宁乡县,其次为湘潭市湘潭县和长沙市浏阳县。在长株潭中心区域(长沙市开福区、湘潭市岳塘区、株洲市石峰区、荷塘区和芦淞区等城市区域)形成一片污染物排放量较小的区域。采用蒙特卡罗法,计算得到区域秸秆露天焚烧源和森林火灾大气污染物排放量95%置信区间的不确定性分别为-84%~168%、-83%~176%。通过定量模拟得到秸秆露天焚烧PM2.5排放量概率密度函数呈对数正态分布。以PM2.5为代表污染物,对其排放量的不确定性贡献率最大的是露天焚烧比例,燃烧效率、水稻产量、水稻草谷比等也是不确定性的重要来源。     

氮氧自掺杂生物质多孔炭修饰阴极的生物电芬顿产电及其对氯霉素的降解性能

以黑豆为前驱体制备出具有多孔形貌的氮氧自掺杂生物炭(NOPC)材料,利用SEM、XPS、XRD、BET等手段对NOPC进行了表征和分析,并将NOPC负载于生物电芬顿体系的阴极碳布上,考察了生物电芬顿的产电性能及其对氯霉素的降解性能。结果表明：负载NOPC的生物电芬顿体系内阻明显降低,最大功率密度有所升高。与纯碳布电极相比,负载NOPC的生物电芬顿体系在24 h内H₂O₂的生成量增加了46.15%,且对50 mg·L⁻¹和1 mg·L⁻¹的氯霉素在24 h的降解率分别为36.38%和100%;而纯碳布的生物电芬顿体系在24 h内的降解率仅有28.45%和56.63%,负载NOPC的生物电芬顿体系对1 mg·L⁻¹氯霉素的降解率提高了43.37%。以上结果表明NOPC不仅可以提高生物电芬顿体系的产电性能,还能提高氯霉素的降解效率,同时也表明生物电芬顿体系更适用于含有低浓度氯霉素水体的处理。