叠置式太阳能加湿除湿海水淡化系统的稳态性能研究

介绍一种基于空气加湿除湿技术的太阳能海水淡化装置,装置中除湿腔叠置在加湿腔的上部,以此缩小装置的占地面积并利用热湿空气自然上升的浮力,形成一种新结构。详细说明装置的结构和运行原理,并研究控制海水运行温度、流量、循环空气流率等参数对装置产水性能的影响。实验结果表明,装置产水量随进水流量和运行温度增加而增加,当温度为90℃时,进水流量为420 kg/h,装置的最大产水量达到10.38 kg/h,装置性能系数GOR最大为1.33。系统在类似条件下的理论产水率达到约15.6 kg/h,性能系数达到1.90。对生化小球和加湿帘2种填料及不同填料厚度的产水性能进行测试,结果表明填料的选择,要结合装置体积和传质效率来综合考虑。     

热空气式加湿除湿海水淡化装置研究

基于喷淋水自循环与太阳能加热空气的方法,设计一种加湿除湿型海水淡化装置。首先对装置的结构及原理进行说明,然后对装置各部分的能量平衡进行分析,最后实验研究装置集热及产水性能。从实验结果可知,淡化装置所匹配的太阳能空气集热器效率在37%～50%之间,在循环风量为164.21 m~3/h、海水喷淋速率为971 kg/h以及淡水喷淋速率为896 kg/h的条件下,装置最大半小时产水量为2.2 kg。此外,研究结果显示,因喷淋水自循环,喷淋速率的变化对装置产水量的影响较小。     

双热质耦合加湿除湿海水淡化性能试验分析

基于加湿除湿海水淡化技术,采用直接接触式除湿方法,设计了双热质耦合加湿除湿海水淡化装置。构建了相关的试验系统,并对海水淡化装置的热力性能进行了试验测试,获得了双热质耦合加湿除湿海水淡化系统设计工况点下的热力性能,并对海水流量、空气流量和气体分布器与海水淡化系统性能的依变规律进行了研究。测试结果表明:在双热质耦合加湿除湿海水淡化系统设计工况下,装置造水量和单位体积造水量分别达到5.3 kg·h~(-1)和16.56 kg·m~(-3)·h~(-1);产水量随着海水流量增加先增加12.5%后减小20.6%;减小空气流量装置的造水量减小了9.7%;加湿器引入气体分布器,装置的产水量增加11.3%。     

两种聚光器联合驱动的鼓泡加湿除湿型太阳能海水淡化系统实验研究

设计一个由太阳能空气集热器和曲面菲涅尔透镜联合驱动的鼓泡加湿除湿型太阳能海水淡化系统,介绍该系统的结构和运行原理,对多曲面聚光器的聚光特性进行光学仿真分析,对装置各部件的能量进行平衡计算,测试系统在实际天气条件下的产水性能,给出太阳辐照度、装置运行温度和产水效率随时间的变化关系。当太阳辐照度平均为795 W/m2时,该装置集热管出口温度最高为64.8℃,产水量约为9.48 kg/d,整体系统热效率为43.5%。     

聚光直热式加湿除湿型太阳能海水淡化装置性能测试与经济性分析

对一种聚光直热式加湿除湿太阳能海水淡化装置进行实验测试,根据其产淡水速率和经济成本,对其长期运行的经济性进行分析。在室内稳定条件下,测试给出海水喷淋温度、加热功率等对产水速率的影响曲线。结果表明,采用双层加湿小球作为加湿层材料的系统产水效果最好,在喷淋温度为73℃时,其产水速率为1.12 kg/h。在实际天气下,也测试给出装置内部的工作温度和产水性能随时间的变化曲线。实验结果表明,在平均太阳直射辐照度为692 W/m~2时,最大产水速率达到0.52 kg/h,装置的平均性能系数达到0.84。     

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。     

多效竖管降膜蒸发太阳能海水淡化装置性能研究

设计一种由平板太阳集热器和海水淡化单元组成的多效同轴竖管降膜蒸发式太阳能海水淡化装置。研究装置的能量流动情况,并在实际天气条件下对装置进行性能测试,给出该装置的产水量和运行温度随运行时间、辐照度的变化曲线。结果表明,装置在实际天气条件下,日产水量最高达到9.92 kg,最大产水速率为2.0 kg/h,是一种理想的太阳能海水淡化器。     

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。     

多效增湿除湿太阳能海水淡化装置的性能试验

文章提出了一种具有规模灵活、操作简单、维护运行成本低廉、易于和可再生能源结合等优点的新型多效增湿除湿太阳能海水淡化装置;介绍了装置的结构和运行原理,进行了海水运行温度、进水流量等影响产水性能的参数的实验研究。研究结果表明,装置产水量随进水流量和运行温度增加而增大,当进水流量为906 kg/h时,装置产水量达到58.14 kg/h。该多效增湿除湿海水淡化系统具有较大的性能提升空间和广阔的应用前景。     

负压对太阳能加湿除湿产淡水性能的影响

为提高淡水产量,设计一种太阳能负压式太阳能加湿除湿海水淡化系统,通过减小加湿腔体内压强来增加湿空气中含湿量,湿空气分别在液环真空泵和除湿腔内冷凝收集得到淡水。湿空气中含湿量上升,日产淡水总量增加。当湿空气温度70 ℃时,加湿腔压强从90 kPa减至70 kPa,含湿量增加154.9 g/kg;加湿腔压强70 kPa时,12：00—14：00可稳定产淡水1.8 kg/h以上,最高可达2.1 kg/h。装置性能系数GOR最高可达1.7。     

Solar desalination using humidification dehumidification processes. Part I. A numerical investigation

A numerical investigation of a humidification dehumidification desalination (HDD) process using solar energy is presented. The HDD system consists mainly of a concentrating solar water heating collector, flat plate solar air heating collector, humidifying tower and dehumidifying exchanger. Two separate circulating loops constitute the HDD system, the first for heating the feed water and the second for heating air. A mathematical model is developed, simulating the HDD system, to study the influence of the different system configurations, weather and operating conditions on the system productivity. The model validity is examined by comparing the theoretical and experimental results of the same authors. It is found that the results of the developed mathematical model are in good agreement with the experimental results and other published works. The results show also that the productivity of the unit is strongly influenced by the air flow rate, cooling water flow rate and total solar energy incident through the day. Wind speed and ambient temperature variations show a very small effect on the system productivity. In addition, the obtained results indicate that the solar water collector area strongly affects the system productivity, more so than the solar air collector area.     

竖管式蒸馏太阳能苦咸水淡化装置性能研究

针对偏远缺水地区提出一种新型竖管式蒸馏太阳能苦咸水淡化装置,利用嵌套圆管之间小空间形成苦咸水受热蒸发冷凝腔从而生成淡水,该装置具有结构紧凑、节省空间、承压性能好等特点。介绍了竖管式蒸馏太阳能苦咸水淡化装置的结构原理,对装置在不同加热功率下淡水产量及蒸发冷凝温度进行了试验研究,得到了不同运行工况下装置的性能系数,探索了提高装置淡水产量的方法,分别研究了在负压运行工况和套筒外壁面水冷负压运行工况下的装置淡水产量和温度变化。结果表明:装置在输入功率为200 W时,性能系数可以达到0.80;工作压力为75kPa,加热温度为80.00℃时,装置淡水产量为0.259kg/h,比相同加热温度下常压时装置淡水产量提高23.90%;当装置套筒外壁面进行水冷强化,工作压力为75kPa,加热温度为70.00℃时,装置淡水产量为0.690kg/h,是非水冷相同运行工况下装置淡水产量的3.62倍。     

太阳能中温闪蒸海水淡化系统产水性能研究

为提高系统产水性能并降低内部结垢,提出一种由非跟踪复合抛物面聚光器加热导热油至100 ℃以上作为供能热源,采用喷雾辅助闪蒸的海水淡化系统。实验研究实际天气中,不同太阳辐照度下进水口温度、进水流量对系统产淡水性能的影响。采用密封压力桶可将进水口温度升至沸点以上,最高可达123 ℃。太阳辐照度波动较大时,进水口温度保持稳定,系统可稳定运行。进水口温度对产水速率影响显著,平均进水口温度从100 ℃升至120 ℃时,产水速率提高47.61%。当进水流量为50 kg/h,压力维持在0.045 MPa时,系统产水速率最大,日累计淡水产量可达11.14 kg/（d·m²）,小时效率为81.45%,单级生产率为9.15%。     

Thermal analysis for system uses solar energy as a pressure source for reverse osmosis (RO) water desalination

As Natural resources are becoming limited and energy price dramatically increased, energy utilization with efficient systems is essentially required to be used in desalination technologies. The use of solar energy in desalination processes is one of the most promising applications of renewable energies. The primary focus on desalination by solar energy is suitable for use in remote areas. A proposed desalination system uses solar radiation, which concentrated by parabolic dish to heat up the working fluid in a closed space. Then the generated pressure in this space used to push salt water into RO module.Daily production rate of fresh water quantity for suggested system compared with other solar techniques is a promising rate for each m² of solar radiation collecting surface. The production rate for one operation cycle could reach to 1800 L/cycle of fresh water at low water salinity (Brackish water with 5000 ppm) and 55 L/cycle at highest water salinity (sea water salinity with 42,000 ppm). The required energy needed to produce 1 kg of fresh water is also promising even when in case of using another type of energy, also operating cycle has ability of repetition according to salinity concentration through sunny hours.     

一种新型太阳能海水淡化系统的实验研究

介绍了一种新型的太阳能海水淡化方法,即结合太阳能空气集热器和太阳能热管、利用空气增湿除湿来实现海水淡化。分别进行了电吹风模拟太阳能空气集热器的蒸发器实验,以及结合3m2太阳能空气集热器和热管集热器的实际装置实验。结果表明,影响蒸发量的主要因素为热空气温度、热空气流量、初始水量、水温、出气孔直径和数量。实验结果表明,装置可获得的最大冷凝量为790g/h,计算出系统的产水率和热力学效率分别为5.59×10-5kg/kJ和12.4%。     

Field test of a solar seawater desalination unit with triple-effect falling film regeneration in northern China

Based on the mechanism of falling film evaporation condensation, a new four-stage distillation unit with triple-effect regeneration has been designed, constructed and field tested. The seawater desalination system is driven by 80 m² all-glass vacuum tube solar collection system with an additional 1 kW wind power system to provide electricity for pumps. The field testing and monitoring of the system had been carried out under the real weather condition for 2 years. The results show that the water production of the system for per unit of solar collector area could reach up to more than 12 kg/m²/day under the fine weather conditions. Water production of the system was stable in long period and the annual production could reach to 250 tons in northern China. The economic performance of the system is also discussed. The cost of water production is estimated approximately 4.6 Dollar/ton for the 15-year service life.     

Modeling and optimization of a solar driven membrane distillation desalination system

The desalination technology using membrane distillation driven by solar energy is a feasible solution for reducing the energy cost. A dynamic simulation model for a solar driven membrane distillation desalination system (SMDDS) is developed on the Aspen Custom Modeler^® (ACM) platform for the system performance and optimization study. The rigorous model for the spiral-wound air gap membrane distillation (SP-AGMD) module takes into account the heat and mass transfer resistances associated with each composing layer. The effects of adopting different objective functions, solar radiation conditions, thermal storage tank configurations, as well as the flowrates of the membrane distillation module and the thermal storage tank on the optimized performance are reported. Simple thermal storage tank and lower flowrate of the membrane distillation module are advantageous to higher water production rate. A control system using conventional PI (Proportional/Integral) controllers is proposed and the water production rate can reach about 87% of the optimal result for clear sky operation.     

Experimental study of a solar desalination pond as second stage in proposed zero discharge desalination process

This work represents the efficiency of a solar desalination pond as a second stage of proposed zero discharge desalination processes to reach fresh water and also concentrated brine from the effluent wastewater of the desalination unit of Mobin petrochemical complex. So a solar desalination pond is constructed after a pretreatment unit to concentrate the softened wastewater to about 20 wt%. The concentrated wastewater is as a suited feed for a forced circulation crystallizer. During one year, the effects of major parameters such as ambient temperature and solar insolation rate are investigated, experimentally. specific gravity in each layer of concentrated brine wastewater is evaluated. Also, evaporation rates are calculated theoretically and are verified by experimental data. Theoretical values predict evaporation rate accurately. Results show good agreement with experimental data. According to results, maximum evaporation rate is 5 l/m² day when the insolation rate is about 24,602 kJ/m² day Solar energy absorption factor on June is max. Also, experimental results show the best proposed time to gain highest thermal energy is on spring therefore performance efficiency of solar desalination pond promote on spring comparing with the other months. Extracted data for specific gravity prove the bottom of solar desalination pond, layer 1, is best zone for energy saving and energy utilization.Also, theoretical values of evaporation rate are calculated according to measured temperatures and related mass conservation equation. Comparison between theoretical and experimental values shows dusty weather, humidity and wind velocity affects on heat transfer coefficients approximately. So, deviations between theoretical data and measured values can be explained. Results show good agreements with experimental data.