一种新型家用太阳能海水淡化装置

设计了一种具有折皱底面的多级迭盘式家用太阳能海水淡化装置。该装置由热管式真空集热管和多级海水淡化器两部分组成。在实际天气条件下,对该装置性能进行了测试,给出了该装置每0.5 h的产水量、累计产水量以及各级水盘的水温随运行时间的变化曲线。实验结果表明,在测试当天累计太阳辐射量22.46 MJ/（m^2.d）条件下,该装置产水量可达9.34 kg/（m^2.d）,单位太阳辐射能产水量为1.50 kg/kWh;该装置的性能系数达到0.956,是传统单级盘式太阳能蒸馏器性能系数的2.7倍。该装置使用简便,运行可靠,维护费用低,在淡水缺乏的岛屿或偏远的咸水湖地区,是一种较为理想的家用太阳能海水淡化装置。     

太阳能海水淡化装置

全世界约有14亿立方公里水资源,其中97.3％为海水,2.7％为淡水,而淡水中约75％又冰冻在两极地带,可供人类直接利用的淡水仅占0.36％,而且分布很不均匀。即使在水资源相对丰富的一些地区,由于人口的增长,工业的发展,以及水源的污染,人们也担心将来会缺水。我国是水资源贫乏国,人均水占有量在全世界居第88位。为了发展生产,保障人民生活需要,开发淡水资源意义十分重大。其中,海水淡化是人工获得淡水的途径之一,已引起越来越多国家的关注。淡化海水需消耗大量能源,这些能源可以是常规能源,也可以是太阳能等新能源。为了节约煤、油、     

四效管式降膜蒸发太阳能海水淡化装置性能研究

增加太阳能海水淡化装置的运行效数可显著地提升其热能利用效率和总产水量。为此,该文设计四效竖管式降膜蒸发太阳能海水淡化装置,对比研究运行效数对装置内环形封闭小空间中水蒸气热质传递的影响,理论分析装置内气体介质传热传质特性,采用试验测试数据对理论计算结果进行验证,同时还对不同运行温度条件下,装置各效产水速率、蒸发冷凝温度、竖直方向温度梯度以及排浓海水温度等参数进行测试分析。结果表明,四效海水淡化装置理论产水速率与试验产水速率变化趋势一致,二者最小偏差为6.08%,当运行温度为80℃时,装置总产水速率为0.95 kg/h,第1效产水速率是第4效产水速率的1.59倍,竖直方向温度差值最大为15.3℃,最高排浓海水温度为51.3℃。     

热法太阳能海水淡化技术研究进展

海水淡化技术的应用是解决淡水资源短缺问题的有效措施,以化石燃料为海水淡化的驱动力会加快能源短缺、导致环境污染等问题,相比之下,利用太阳能加热海水进行淡化对环境友好,既缓解了淡水资源匮乏的问题,又符合可持续发展的要求.另外,在加热海水的过程中,可以回收利用冷凝潜热,提高海水淡化系统的单位产水量.因此,整理了太阳能与传统热...     

低温热源驱动两级负压管式淡化装置性能研究

设计制造一种以太阳能等低温热源驱动,并在负压下运行的两级管式淡化脱盐装置。在44及62℃恒温热源加热条件下,测试装置处于101、60及20 kPa运行压力时的水温及淡水产率,对其性能进行评估。结果表明负压运行可使蒸馏系统产水率提高到常压运行时的3倍以上,同时可提升装置对热能的利用效率。此外,数据表明真空辅助技术应用于小型淡化装置时,电能消耗较低,操作压力为60及20 kPa时,真空泵每小时耗电量分别约为0.00035及0.009 kWh。结合实验数据对2～5级管式蒸馏器的能量利用效率进行估算,当热源温度为70℃时,5级蒸馏器性能系数在60 kPa负压下可达3.79。     

小型太阳能海水淡化装置

基于空气增湿-除湿海水淡化技术,采用热海水与空气逆流对喷的空气加湿器,设计了结合太阳能集热器的小型太阳能海水淡化系统。试验结果表明,该结构的空气加湿器具有很好的加湿效果,出口空气相对湿度可达到98%以上。当喷水温度为60℃、空气流量为11.8 L/s时,该小型海水淡化装置产水率可达3.42 kg/h。     

直接减压式太阳能海水淡化装置

本文介绍已获国家专利（申请号：９８２１４８９９．２）的太阳能海水淡化设备。设备利用高效太阳能集热技术加热海水,利用真空减压技术收集水蒸汽制备淡水,该设备是一种适于为缺乏淡水的海边和岛屿生活的人们提供淡水的处理设备。     

潜热回收的太阳能海水淡化装置

本文阐述了一种与常规太阳能蒸馏不同的利用冷凝热和海水淡化时释放出的显热系统。经分析,其性能较佳。目前该系统正在埃及施工。如图1所示:它由一台加湿器、一台太阳能蒸馏器或通道,一台冷凝器和一个池子所组成。在加湿器中,进入的环境空气由池子中的温暖盐水加湿加热。如果盐水的出口温度高于环境温度,则返回到池水中,反之,则排出。太阳能蒸馏器是一个长条形玻璃盖板的通道,约长200米。其横载面如图(2)所示。     

漂浮式聚光升膜多效太阳能蒸馏器的性能研究

提出一种漂浮在海面上进行淡化产水的聚光升膜多效太阳能蒸馏器,该淡化装置包含一个抛物面聚光镜和多个垂直布置的蒸发-冷凝单元。采用吸水芯作为蒸发器,利用毛细吸力使海水形成上升的液膜,有效减少了加热损失。建立理论模型分析装置内部的传热传质过程。通过实验研究不同运行参数对装置温度、产水量和比能耗的影响。室内稳态研究结果表明,当太阳辐照度为900 W/m²时,蒸馏器内部温差为56.9℃,产水率可达到2.64 kg/(m²·h)。在户外平均太阳辐照度为603.7 W/m²的条件下,装置一天产水量为5.3 kg/(m²·d),日平均比能耗为1591.6 kJ/kg。     

Performance analysis in stepped solar still for effluent desalination

In this work, a stepped solar still and an effluent settling tank are fabricated and tested for desalinating the textile effluent. The effluent is purified in an effluent settling tank. In this tank, large and fine solid particles are settled and clarified. The settled effluents are used as raw water in the stepped solar still. For better performance, the stepped solar still consists of 50 trays with two different depths. First 25 trays with 10 mm height and the next 25 trays with 5 mm height are used. Fin, sponge, pebble and combination of the above are used for enhancing the productivity of the stepped solar still. A maximum increase in productivity of 98% occurs in stepped solar still when fin, sponge and pebbles are used in this basin. Theoretical analysis agrees well with experimental results.     

A low cost design solar desalination unit

A novel low cost design solar still is described and performance data are presented. The proposed design eliminates the need for support or side-walls, as required in most conventional solar still designs. A comparison of the measured still productivity values between the proposed design and a large solar distillation plant constructed in India has shown that our design simplification has not affected still performances. An economic analysis, based upon the fraction of still construction cost dedicated to the still wall construction, has indicated that the proposed design should reduce the overall cost/m² of the solar still construction by at least 20%.     

两效竖管式太阳能苦咸水淡化装置性能研究

提出了一种新型两效竖管式太阳能苦咸水淡化装置,介绍了该装置的结构和运行原理,对其性能进行了试验研究和分析,给出了装置在室内电加热试验中各测点温度变化曲线、淡水产量和室外测试结果,计算了装置在室内测试条件下的性能参数GOR。试验结果表明:在室内测试中,该装置在加热功率为305 W的条件下,淡水产量为0.39 kg/h,其性能系数为0.84;在室外试验中,该装置的淡水产量可以达到1.25 kg/h。     

Performance of a self-regulating solar multistage flash desalination system

A 10,000-1 solar multistage flash desalination system was designed and tested at Kuwait Institute for Scientific Research. The system consisted of a 220 m² solar line-concentrating collector field, 7000-1 thermal storage tank and a self-regulating 12-stage multistage flash desalination subsystem. The collector field, equipped with closed-loop tracking system, was installed with individual troughs oriented in the north-south direction. The thermal storage subsystem was useful in leveling off the thermal energy supply and allowing the production of desalinated water to continue during periods of low radiation and nighttime. The self-regulating capability of the desalination subsystem allowed for the adjustment of the flow rate and pressure, in the various stages of the desalination subsystem, according to the relative difference between the hot brine and input sea water temperatures. This allowed for maintaining a relatively high overall efficiency.     

Flash vapor solar powered desalination unit optimization study

In this work a flash vapor desalination unit was assembled which consisted of a solar water-cooled system of three flat plate collectors and a storage tank. A copper coil was immersed inside the tank, the saline water was pumped through the coil and delivered to the flash tank, the vapor then being flashed to the surroundings. The saline water level in the flash tank was taken as a measure of the quantity flashed. The temperature of both cooling and saline water at the inlet and outlet were measured; solar irradiation and wind speed were also recorded. The mass ratio (R) which is the ratio of the rate of the mass flashed to that of saline water circulated and the total unit efficiency were taken as dependent variables. Graphical and numerical optimization methods were conducted to find the values of the dependent variables. The optimization algorithm is described and the results are shown.     

Economic analysis of a solar assisted desalination system

This paper deals with an economic analysis of a solar assisted desalination system. The analysis is carried out for four types of applications, two domestic, a hotel and a village. It is shown that solar desalination is viable for the two bigger installations (hotel and village) with water prices below C£0.89/m³. It is also shown that the water cost is insensitive to the changes in method of payment or to small variations in direct costs. It is not worth operating the desalination system solely on solar energy due to the high cost of the desalination system and the diurnal nature of the solar input which implies high percentage of inactive time.     

Brackish water desalination by a stand alone reverse osmosis desalination unit powered by photovoltaic solar energy

Desalination of brackish water as a viable option to cope with water scarcity and to overcome water deficit in Jordan is assessed. A stand alone reverse osmosis (RO) desalination unit powered by photovoltaic (PV) solar energy is proposed, and a computer code in C++ was generated in order to simulate the process, and to predict the water production at 10 selected sites based on the available solar radiation data, sunshine hours and salinity of the feed water (TDS of 3000, 5000, 7000, and 10,000 mg/L). It was found that most of the selected sites showed favorable application of the proposed system in Jordan. Tafila, Queira, Ras Muneef, H-4, and H-5 are the most favorable sites. With TDS of 7000 mg/L, the highest annual water production of 1679 m³/year was observed in Tafila, followed by Queira with production of 1473 m³/year. Ras Muneef, H-4, and H-5 showed close to each other production of 1363, 1345, and 1340 m³/year, respectively. Among the most favorable sites (Tafila, Queira, Ras Muneef, H-4, and H-5), Ras Muneef was found to be the best site in terms of the daily amount of water produced during the driest months of the year (May–September). Its production during these months forms about 65% of its total daily water production during a 1-year cycle, while for each of the other most favorable sites namely Tafila, Queira, H-4, and H-5, a 61% of production was observed during the same period.     

Performance of a second generation solar cooling unit

This paper describes the performance of a 1.5 ton solar-operated absorption refrigeration unit operating with a 14 m² flat-plate solar collector system and containing five heat exchangers: the generator, the absorber, the condenser, the solution heat exchanger (all of these being of shell-and-tube type) and finally the evaporator, which is of the fin-and-tube type. One circulation pump is used for solution flow and another for the hot water flow. The condenser and the absorber are both cooled by city mains water. This particular unit, called the second generation unit, is compared with an earlier, first-generation unit (FGU), i.e. a low-cost, locally manufactured unit of 0.5 ton capacity. The results are based on the observed operation of the unit during hours of sufficient solar irradiance in April and May, the beginning of the air-conditioning season in Jordan. The variation of both the generator and evaporator temperatures during the test period are reported. Also reported is the performance of the unit as measured by the actual and theoretical (ideal) coefficients of performance, both of these being functions of the temperatures and solar irradiance. The maximum values obtained for both actual and theoretical coefficients of performance were 0.85 and 2.7, respectively. These values are within the range of values published in literature, and higher than those obtained by the FGU.     

Performance analysis of the power conversion unit of a solar chimney power plant

The power conversion unit (PCU) of a large solar chimney power plant consists of one or several turbogenerators, power electronics, a grid interface and the flow passage from collector exit to chimney inlet. The main goals of this paper are to analyze the performance of the PCU and its interaction with the plant as well as to compare three configurations from an efficiency and energy yield point of view.First, a reference plant is defined and the plant performance data taken from simulations with a model found in the literature are analyzed, and the matching of the turbine(s) to the characteristic of the plant is discussed. It was found that a well designed turbine can be run at high efficiency over the entire operating range, as the plant performance data can be fitted using the ellipse law of Stodola.Loss models for all components of the power conversion unit are then defined, and the impact of the various losses on the overall performance is assessed. Three configurations of the PCU are compared, i.e. the single vertical axis, the multiple vertical axis and the multiple horizontal axis turbine configuration. It is found that the single vertical axis turbine has a slight advantage with regards to efficiency and energy yield because certain loss mechanisms are not present. But its output torque is tremendous, making its feasibility questionable. It is shown that with designing the flow passage in an appropriate manner the aerodynamic losses can be kept low. The assumption made by many other researchers that the total-to-total efficiency of the PCU is 80 % has been confirmed with the present model. Further, it has been shown that the PCU efficiency deteriorates significantly with increasing diffuser area ratio but improves only slightly with reducing the diffuser area ratio below unity.     

Performance analysis of a PEM fuel cell unit in a solar–hydrogen system

In this paper, energy and exergy analyses for a 1.2 kWp Nexa PEM fuel cell unit in a solar-based hydrogen production system is undertaken to investigate the performance of the system for different operating conditions using experimental setup and thermodynamic model. From the model results, it is found that there are reductions in energy and exergy efficiencies (about 14%) with increase in current density. These are consistent with the experimental data for the same operating conditions. A parametric study on the system and its parameters is undertaken to investigate the changes in the efficiencies for variations in temperature, pressure and anode stoichiometry. The energy and exergy efficiencies increase with pressure by 23% and 15%, respectively. No noticeable changes are observed in energy and exergy efficiencies with increase in temperature. The energy and exergy efficiencies decrease with increase in anode stoichiometry by 17% and 14%, respectively. These observations are reported for the given range of current density as 0.047–0.4 A/cm². The results and analyses show that the PEM fuel-cell system has lower exergy efficiencies than the corresponding energy efficiencies due to the irreversibilities that are not considered by energy analysis. In comparison with experimental data, the model is accurate in predicting the performance of the proposed fuel-cell system. The parametric and multivariable analyses show that the option of selecting appropriate set of conditions plays a significant role in improving performance of existing fuel-cell systems.