Enhancement of freshwater production of the seawater greenhouse condenser

Seawater greenhouse(SWGH)is a technology established to overcome issues related to open field cultivation in arid areas,such as the high ambient temperature and the shortage of freshwater.It adopts the humidification-dehumidification concept where evaporated moisture from a saline water source is condensed to produce freshwater within the greenhouse body.Various condenser designs are adopted to increase freshwater production in order to meet the irrigation demand.The aim of this study was to experimentally investigate the practicality of using the packed-type direct contact condenser in the SWGH to produce more freshwater at low costs,simple design and high efficiency,and to explore the impact of the manipulating six operational variables(inlet air temperature of the humidifier,air mass flowrate of the humidifier,inlet water temperature of the humidifier,water mass flowrate of the humidifier,inlet water temperature of the dehumidifier and water mass flowrate of the dehumidifier)on freshwater condensation rate.For this purpose,a direct contact condenser was designed and manufactured.Sixty-four full factorial experiments were conducted to study the effect of the six operational variables.Each variable was operated at two levels(high and low flowrate),and each experiment lasted for 10 min and followed by a 30-min waiting time.Results showed that freshwater production varied between 0.257 and 2.590 L for every 10 min.When using Minitab statistical software to investigate the significant variables that contributed to the maximum freshwater production,it was found that the inlet air temperature of the humidifier had the greatest influence,followed by the inlet water temperature of the humidifier;the former had a negative impact while the latter had a positive impact on freshwater production.The response optimizer tool revealed that the optimal combination of variables contributed to maximize freshwater production when all variables were in the high mode and the inlet air temperature of the humidifier was in the low mode.The comparison between the old plastic condenser and the new proposed direct contact condenser showed that the latter can produce 75.9 times more freshwater at the same condenser volume.

Magnetic Sources of Gold and Freshwater Rivers: Using Ultra-Strong Magnets in the Production of Freshwater and Gold Fishing from Salty and Freshwater Currents

The research studies the least expensive ways to produce freshwater from the sea and extract gold, by taking advantage of the characteristics of seawater with a high density compared to the lower density of freshwater, and different estimates of the amount of gold present in seas and oceans (between 10 - 30 grams per 1 km3) and the total volume of gold in the sea (between 15 - 45 thousand tons), which will often be more than that due to the continuous sedimentation from the rivers, and the gold contains impurities that are attracted to the magnet, and therefore it is possible to catch it by means of “super strong magnets”;its strength reaches 1000 tons;it is placed at the bottom of a designated basin, so that the gold is attracted to the bottom, and the most saline types of water are deposited at the bottom, and freshwater floats to the top (by 1/4), and this is done by allocating a separate building to the magnet and large areas around it, and designing a water course dedicated to that, and lakes to collect Seawater and pass it on the magnet, which will cause the formation of lakes for freshwater, and other lakes for types of seawater minerals, and it is also possible to use “super-strong magnets” to attract gold from river water and seas, and from the tailings of gold mines, and it will eventually cause Providing huge quantities of freshwater to be used in agricultural and industrial expansion and the establishment of new societies, and gold is gradually turning into a commonly used metal just a “yellow stainless metal”.

Storing Freshwater Versus Storing Electricity in Power Systems with High Freshwater Electric Demand

We consider a power system whose electric demand pertaining to freshwater production is high(high freshwater electric demand),as in the Middle East,and investigate the tradeoff of storing freshwater in tanks versus storing electricity in batteries at the day-ahead operation stage.Both storing freshwater and storing electricity increase the actual electric demand at valley hours and decrease it at peak hours,which is generally beneficial in term of cost and reliability.But,to what extent?We analyze this question considering three power systems with different generation-mix configurations,i.e.,a thermal-dominated mix,a renewable-dominated one,and a fully renewable one.These generation-mix configurations are inspired by how power systems may evolve in different countries in the Middle East.Renewable production uncertainty is compactly modeled using chance constraints.We draw conclusions on how both storage facilities(freshwater and electricity)complement each other to render an optimal operation of the power system.

Rational Design of High-Performance Bilayer Solar Evaporator by Using Waste Polyester-Derived Porous Carbon-Coated Wood

Wood-based bilayer solar evaporators,which possess cooperative advantages of natural wood and photothermal conversion coating including fast water transportation,low heat conduction,renewability,and high light absorbability,hold great promise for water purification.However,previous studies suffer from low evaporation rates and high cost of coatings,and lack a deep understanding how the porous structures of coating layer function.Herein,a novel bilayer solar evaporator is designed through facile surface coating of wood by low-cost porous carbon from controlled carbonization of polyester waste.The porous carbon bears rich oxygen-containing groups,well-controlled micro-/meso-/macropores,and high surface areas(1164 m^(2) g^(−1)).It is proved that porous carbon improves sunlight absorption and promotes the formation of numerous water clusters to reduce water evaporation enthalpy.Owing to these combined features,the bilayer solar evaporator exhibits high evaporation rate(2.38 kg m^(−2) h^(−1)),excellent longterm stability,and good salt resistance.More importantly,a large-scale solar desalination device for outdoor experiments is developed to produce freshwater from seawater.The daily freshwater production amount(3.65 kg m^(−2))per unit area meets the daily water consumption requirement of one adult.These findings will inspire new paradigms toward developing efficient solar steaming technologies for desalination to address global freshwater shortage.