Atmospheric Water Generator Research Articles

Experimental Parameter Tuning of a Portable Water Generator System Based on a Thermoelectric Cooler

Atmospheric Water Generators (AWG) are a promising technology solution to the water scarcity in the world. However, their main drawback is the high power consumption. This paper presents the experimental optimization process of a Portable Atmospheric Water Generator (PAWG) prototype based on a thermometric cooler. This process was developed by an exhaustive search of the experimental solution space, which was generated by parametric sweeps of two parameters (i.e., control voltages in the PAWG), which are related to the power consumption of the PAWG and the physical variables involved in the water condensation process (i.e., the airflow and the temperature on the water condenser element). As a result, we found the existence of two optimal operation points under a constant value of relative humidity; one of them maximizes the amount of water generated, and the other one maximizes the system performance (i.e., the ratio between the generated water and consumed power in mL/Wh). The resulting Figures of Merit (FoMs) of the PAWG prototype were 0.33 mL/h of generated water and 0.22 mL/Wh for the system performance.

Humidity reduction by using hetero-layered metal–organic framework nanosheet composites as hygroscopic materials

A super hygroscopic material with functionalities of humidity capture, in situ liquefaction, and fast water release triggered by natural sunlight, has been prepared, providing a good strategy for next-generation atmospheric water generators.

Passively improving liquid sorbent based atmospheric water generation by integration of fuel cell waste products

Although interfacial atmospheric water generation is a new concept that can generate freshwater from renewable energy, its water generation rate is too low for widespread use. This paper proposes to integrate the fuel cell to a similar device but instead uses the electrochemically generated waste heat to drive the regeneration process of the liquid sorbent material. Furthermore, the electrochemically generated water is used to increase the relative humidity of the incoming air. Thus, by solely relying on the fuel cell waste products, water recovery rates that are theoretically higher than direct atmospheric water generation are achieved. A steady-state physics model based on the difference in water partial pressure to achieve water absorption and desorption is used to analyze the liquid sorbent device’s performance. Furthermore, the effect of various design parameters such as the salt mass fraction, the fuel cell operating power, the ambient relative humidity, etc. have been studied. Results demonstrate that up to 1.8 kg/h and 0.82 kg/(m2 h) of liquid water can be obtained by fuel cells with an operating temperature range that is consistent with the high-temperature proton exchange membrane fuel cell. This implementation would allow an FC waste heat utilization ratio of up to 0.8.

Producing Safe Drinking Water Using an Atmospheric Water Generator (AWG) in an Urban Environment

Alternative new technologies are urgently needed to overcome the rapidly increasing global water scarcity. Atmospheric dew water is a potential source of potable water, as the earth’s atmosphere contains billions of tons of fresh water (98% in a vapor state). The atmospheric water generator (AWG) converts water vapor into liquid water and is a promising solution for water scarcity. We provide the first comprehensive analysis of the chemical profiles of water produced for several months by an AWG in the city of Tel Aviv, Israel. Metals, inorganic ions, volatile organic compounds (VOCs), and semi-VOCs were analyzed in the dew water. The main elements found were ammonium, calcium, sulfate, and nitrate. Location of the sampling site in an urban residential area, between major traffic routes, likely affected the chemical composition of the produced dew water. Nevertheless, the produced water nearly always (day and night in different seasons) met the WHO and Israeli drinking water standards. Thus, even in a highly developed urban environment, the AWG offers an excellent alternative source of safe drinking water throughout the year.

The fuel cell and atmospheric water generator hybrid system for supplying grid-independent power and freshwater

Despite the success of atmospheric water generators for providing drinking water to remote regions, this technology has a high specific energy consumption. This paper proposes to reuse the electrochemical water of the fuel cell for the vapor compression cycle based atmospheric water generator (VCC-AWG); After passing through an ambient heat exchanger to remove the electrochemical waste heat, the fuel cell flue gas that enters the VCC-AWG is at a higher relative humidity than natural atmospheric air, thus the freshwater yield per energy input can be significantly increased. Hence, the FC-VCC-AWG hybrid system is proposed to be a power and freshwater supply of a grid-independent home. The fuel cell model, the vapor compression cycle’s thermodynamic model, and humid air physics are coupled to analyze the overall system in terms of the fuel cell’s working condition, incoming airflow rate, compressor power consumption, and the ambient relative humidity. When RH = 0.75, adding a 2 kW fuel cell generated up to 3 kg/hr of freshwater, which is 50% higher than excluding the FC. The specific energy consumption can be 200 Wh/kg, so the VCC-AWG can be integrated with small sacrifices to the FC power output.

Increasing the efficiency of a Peltier device by assessing the thermal performance of liquid-cooled microchannel heat sinks

Water is, arguably, Earth's most valuable and vital resource. Devices that extract water from the atmosphere have been intensely researched as a means of harvesting potable water in environments where it is otherwise scarce. One such device is a Thermoelectric Cooler (TEC); a device that utilises the Peltier effect to cool a system. TECs are a promising solution for atmospheric water generation (AWG) over their competitors due to their simplicity and refrigeration capabilities. Despite these advantages, TECs are still considered mostly inefficient as they demand relatively high costs and energy consumption. This meta-analysis focuses on optimising the efficiency of small-scale Peltier devices. It explores the means of optimising the liquid cooled heat sink by using a specific flow field microchannel configuration such that less pumping power is required to push the coolant and more energy can be saved. A combination of optimal operating current of the Peltier device and of a novel flow liquid-cooled microchannel heatsink configuration with bifurcated fins using Galinstan as a coolant promises a significant increase in water production per unit of energy consumption for the AWG system.

MOF water harvesters.

The advancement of additional methods for freshwater generation is imperative to effectively address the global water shortage crisis. In this regard, extraction of the ubiquitous atmospheric moisture is a powerful strategy allowing for decentralized access to potable water. The energy requirements as well as the temporal and spatial restrictions of this approach can be substantially reduced if an appropriate sorbent is integrated in the atmospheric water generator. Recently, metal-organic frameworks (MOFs) have been successfully employed as sorbents to harvest water from air, making atmospheric water generation viable even in desert environments. Herein, the latest progress in the development of MOFs capable of extracting water from air and the design of atmospheric water harvesters deploying such MOFs are reviewed. Furthermore, future directions for this emerging field, encompassing both material and device improvements, are outlined.

Extracting water content from the ambient air in a double-slope half-cylindrical basin solar still using silica gel under Egyptian conditions

Direct generation of drinking water from ambient air using sunlight is of great interest for many populations. Here, a new desiccant mechanism using a highly hygroscopic silica gel was tested on the double-slope half-cylindrical basin solar still (DS-HCBSS) to extract the water content from the ambient air. As this mechanism is new to be applied into the solar still, an experimental and predictive study was conducted to investigate the thermal performance of the solar still under this modification. The modification was done in a double-slope half-cylindrical basin solar still, which has four longitudinal fins from inside to increase the surface area. The basin liner of the solar still and the fins were covered by a layer of silica gel with a thickness of 1.5 cm. A parabolic trough solar collector was used to raise the temperature inside the solar still during daytime solar illumination. The productivity of the DS-HCBSS with silica gel was enhanced by about 72% and 166% when longitudinal fins and longitudinal fins with gravels were used, respectively. Moreover, the efficiency of the DS-HCBSS with silica gel was increased by 15% and 35% when longitudinal fins and longitudinal fins with gravels were used, respectively. The best accumulated productivity (400 mL/m2) was recorded for the DS-HCBSS with silica gel, longitudinal fins, and gravels. Finally, a Neuro-fuzzy Inference System (ANFIS) model was employed to predict the process response (productivity) of the investigated systems under different process input factors (ambient temperature and solar irradiance). The predictive model obtained a good agreement with the experimental results. The experimental results revealed that the double-slope half-cylindrical basin solar still with the modification provides a new concept for Air Water Harvesting (AWH) and atmospheric water generation.

Experimental investigations on a portable atmospheric water generator for maritime rescue

Abstract To offer an alternative for supplying fresh water to people in distress in tropical seas before rescue or to garrison soldiers on a small reef, a portable solar-photovoltaic atmospheric water generator was designed and tested experimentally, and is composed of a water generating module, a water purifying module, a power supply and control module, and a buoyancy module. The results showed that the best water production rate of 460 mL/h was achieved when Tin = 27, RHin = 92%, Qa = 600 m3/h, with the desalination rate above 99.65%, proving itself a feasible solution as a portable desalination device. The daily water production can reach 5.52 L/d, which is more than twice the minimum quantity of the WHO drinking water standard (2.5 L/capita-day), and the energy consumption can be controlled under 200 W. The influences of major operating parameters on the device performance were analyzed and performance comparisons were carried out with the reported AWG products/prototypes. By integrating with a distress signal launcher and positioning module to shorten rescue time, the device has the potential to be employed as a small rescue platform for people in distress in tropical oceans, carried on board ship as a precaution.

Improving atmospheric water production yield: Enabling multiple water harvesting cycles with nano sorbent

Clean water shortage has long been a challenge in remote and landlocked communities especially for the impoverished. Atmospheric water is now considered as an unconventional but accessible fresh water source and sorption-based atmospheric water generator (AWG) has been successfully demonstrated a reliable way of harvesting atmospheric water. The water vapor sorbents with high water uptake capacity and especially fast vapor sorption/desorption kinetics have become the bottleneck to a desirable clean water productivity in AWG. In this work, we developed a new nano vapor sorbent composed of a nano carbon hollow capsule with LiCl inside the void core. The sorbent can capture water vapor from ambient air as much as 100% of its own weight under RH 60% within 3 h and quickly release the sorbed water within just half hour under 1 kW/m2 sunlight irradiation. A batch-mode AWG device was able to conduct 3 sorption/desorption cycles within 10 h during one day test in the outdoor condition and produced 1.6 kgwater/kgsorbent. A prototype of continuous AWG device was designed, fabricated, and successfully demonstrated, hinting a possible way of large-scale deployment of AWG for practical purposes.

Moist Air Condensation on Inclined Hydrophobic Metallic Surfaces: Simulation & Experiments

Atmospheric Water Generators (AWGs) are popularly used for harvesting portable water from atmospheric air of hot, humid and arid regions of the world. Hydrophobic metallic surfaces are preferred in AWGs systems because condensation of moist air on/underneath these surfaces have high efficacy. There are several issues to fabricate hydrophobicity on metallic surfaces. Although with the advent of Nanotechnology and thin film coating technologies, the fabrication of hydrophobicity on metallic surfaces has become easier and realizable in the recent era. In this manuscript, a comprehensive mathematical model is developed for simulating the moist air condensation in the form of droplets on various substrates and in different environmental conditions. The experiment is carried out for validation of the present model. Post validation, the effect of surface hydrophobicity, relative humidity and degree of sub-cooling on the condensation rate are addressed. The simulation results show that vertically orientated metallic surfaces having a high contact angle along with low contact angle hysteresis are efficient for condensing unit. Larger condensation rates are observed at higher relative humidity and a high degree of sub-cooling. This research is helpful for designing efficient and effective AWGs for the hot and humid region.

An Interfacial Solar-Driven Atmospheric Water Generator Based on a Liquid Sorbent with Simultaneous Adsorption-Desorption.

Water scarcity is one of the greatest challenges facing human society. Because of the abundant amount of water present in the atmosphere, there are significant efforts to harvest water from air. Particularly, solar-driven atmospheric water generators based on sequential adsorption-desorption processes are attracting much attention. However, incomplete daytime desorption is the limiting factor for final water production, as the rate of water desorption typically decreases very quickly with decreased water content in the sorbents. Hereby combining tailored interfacial solar absorbers with an ionic-liquid-based sorbent, an atmospheric water generator with a simultaneous adsorption-desorption process is generated. With enhanced desorption capability and stabilized water content in the sorbent, this interfacial solar-driven atmospheric water generator enables a high rate of water production (≈0.5 L m-2 h-1 ) and 2.8 L m-2 d-1 for the outdoor environment. It is expected that this interfacial solar-driven atmospheric water generator, based on the liquid sorbent with a simultaneous adsorption-desorption process opens up a promising pathway to effectively harvest water from air.

Pengaruh Penggunaan Fan dan Debit Fluida terhadap Efisiensi Kerja Atmospheric Water Generator

The purposes of this study are to investigate the effect of condenser cooling fan addition and airflow rate on the performance of Atmospheric Water Generator (AWG). In this work, humid air from the environment was supplied into AWG at 15 lpm. Then, it was condensed in the system with and without using a condenser cooling fan. The fan airflow rate also varied from 0.09 m 3 /s to 0.16 m 3 /s in order to better assess AWG performance. The results showed that the use of a condenser cooling fan can improve the Coefficient of Performance (COP) and the efficiency of the Atmospheric Water Generator. The average value of COP actual of 2.499 and the highest efficiency of 79.07% was achieved by an Atmosphere Water Generator equipped with a condenser cooling fan at an airflow rate of 0.16 m 3 /s.

Is Atmospheric Water Generation an Economically Viable Solution?

The increasing pressure on freshwater resources motivates the need for exploring new water harvesting methods, critical for global sustainable development. Atmospheric Water Generator (AWG), or air-to-water, is a potentially efficient but under-explored component of the water solutions portfolio. We offer the first bottom-up model of AWG in the environmental economics and policy literature to assess the economic potential and riskiness of a representative AWG system. The model is used to estimate the performance of a typical AWG machine in ten locations with heterogeneous climate and economic conditions. Using a four-year time-series, we also provide estimates of the value-at-risk for water production. Assuming a perfect substitution between AWG machines and bottled water, the financial performance of the AWG machines demonstrate an attractive return to investments in the majority of locations. These numbers show the emerging AWG industry has some untapped merits to contribute toward solving global water problems. Our work can inform water supply debates in both developed and developing countries.

A Feasibility Study on the Use of an Atmospheric Water Generator (AWG) for the Harvesting of Fresh Water in a Semi-Arid Region Affected by Mining Pollution

Worldwide, the shortage of fresh water has increased exponentially due to population growth and contamination of available water, especially in water tables that provide water for general consumption. One of the main pollutants of water is arsenic (As), present in the environment and in most mining/metallurgical processes, which is a major health risk, especially as a carcinogen. In the region of Matehuala, San Luis Potosi (SLP), Mexico, a highly productive mining area, arsenic concentrations of 138.1 mg/kg have been found in soils—6.2 times higher than what is allowed in domestic soils, while in water it is reported up to 158 mg/L, exceeding permissible limits for human consumption. In addition to As pollution, the region suffers from water shortage both in the city and in rural communities. Therefore, it is necessary to explore new technologies to provide the population with fresh water. This paper presents a feasibility study on the use of an atmospheric water generator (AWG) to capture fresh water in the region of Matehuala, SLP. The region was found to have the necessary environmental conditions to use AWGs, with an annual average relative humidity (RH) of approximately 60%. Using a mathematical model of a dehumidifier, water harvesting can be evaluated under the region’s prevailing climatic conditions. The month with lowest harvest was found to be January, with 0.89 to 3.6 L/day, while the month with largest harvest was August at 3.9 to 18 L/day and water production costs of 0.0093 and $ 0.038 USD/L, respectively. The study concludes that the use of AWGs would help alleviate water shortages, thus benefiting marginalized people or communities, preserving ecosystems and the environment.

An Interfacial Solar Heating Assisted Liquid Sorbent Atmospheric Water Generator.

Harvesting water from air is a promising strategy for fresh-water production, and it is particularly desirable for areas that lack direct access to clean water. While high-concentration liquid sorbent is well-known for high sorption, it has not been widely used for atmospheric water collection, being primarily limited by the difficulty in desorption. Interfacial solar heating based on a salt-resistant GO-based aerogel is now shown to enable a high-concentration liquid sorbent (CaCl2 50 wt % solution) based atmospheric water generator. Fresh water (2.89 kg m-2 day-1 ) can be produced at about 70 % relative humidity, with only solar energy input and energy efficiency of desorption as high as 66.9 %. This low-cost and effective approach provides an attractive pathway to extract water from air, to relieve the thirst of arid, land-locked, and other areas where fresh water is scarce.

An Interfacial Solar Heating Assisted Liquid Sorbent Atmospheric Water Generator

AbstractHarvesting water from air is a promising strategy for fresh‐water production, and it is particularly desirable for areas that lack direct access to clean water. While high‐concentration liquid sorbent is well‐known for high sorption, it has not been widely used for atmospheric water collection, being primarily limited by the difficulty in desorption. Interfacial solar heating based on a salt‐resistant GO‐based aerogel is now shown to enable a high‐concentration liquid sorbent (CaCl2 50 wt % solution) based atmospheric water generator. Fresh water (2.89 kg m−2 day−1) can be produced at about 70 % relative humidity, with only solar energy input and energy efficiency of desorption as high as 66.9 %. This low‐cost and effective approach provides an attractive pathway to extract water from air, to relieve the thirst of arid, land‐locked, and other areas where fresh water is scarce.

The Experiment of Producing Freshwater from the Air Using Thermoelectric Cooler for the Need of Drinking Water in a Lifeboat

A limitation of freshwater supply in a lifeboat during sea survival situation caused by a ship accident could endanger survivor’s life. An availability of freshwater is critical for people to survive during search and rescue time. Therefore, it is very important to have a device that can produce freshwater continuously in a lifeboat. A capacity of the lifeboat is around for 20 people. In this research, four model of atmospheric water generator (AWG) namely Model I, Model II, Model III, and Model IV has been designed, fabricated, and tested. All models are tested for one hour with humid air flow is 20 cfm. The atmospheric condition is 78% relative humidity and 30 0 C temperature. The cooling process in AWG device use a thermoelectric cooler (TEC). Based on the result of experiments, the Model IV atmospheric water generator has a best result. The Model IV can produce 53 mL/hr of freshwater. By using 6 sets of the Model IV AWG, a total 7.63 liter/day of freshwater could be produced in that lifeboat. The electricity power supply for those AWG is served by 4 solar panels which each produce 295 WP. The electricity energy from solar panels is saved in 9 power storages or batteries which each has 100 AH and 12 V voltage

Enhancing the Water Capacity in Zr-Based Metal–Organic Framework for Heat Pump and Atmospheric Water Generator Applications

According to the European Commission, in 2016 the residential sector represented 25.4% of the final energy consumption. Heating and cooling in EU households account for 69.1% of the total energy consumption. The fraction of 84% for heating and cooling is still generated from fossil fuels, and only 16% is generated from renewable energy. To decrease carbon dioxide emissions of fossil fuel consumption, it is crucial to find alternatives to supply the heating and cooling demand. Alternatives such as adsorption-based heat pumps and desiccant cooling systems are receiving much attention because of their moderate energy consumption. These systems are based on the energetic exchange during the adsorption/desorption of working fluids. In this work, we combined experiments and simulations to evaluate the viability of several zeolites and MOFs with water for cooling systems applications. We combined the study of adsorption mechanisms and the dynamics of water inside the pores of the structures, thereby obtaining an overall understanding of the working pair. We found that the Al content in FAU-topology zeolites is a key factor for an efficient process. We also identify ZJNU-30 metal-organic framework as a suitable candidate for cooling applications because of its outstanding water capacity, cooling capacity, and coefficient of performance.

Hybrid Hydrogel with High Water Vapor Harvesting Capacity for Deployable Solar-Driven Atmospheric Water Generator.

The Earth's atmosphere holds approximately 12 900 billion tons of fresh water distributed all over the world with fast replenishment. Atmospheric water harvesting is emerging as a promising strategy for clean water production in arid regions, land-locked areas, and remote communities. The water vapor sorbent is the key component for atmospheric water harvesting devices based on absorbing-releasing process. In this work, a flexible hybrid photothermal water sorbent composed of deliquescent salt and hydrogel was rationally fabricated. It possesses superior water sorption capacity even in low humidity air thanks to the deliquescent salt and maintains a solid form after it sorbs a large amount of water owing to the hydrogel platform. The harvested water could be easily released under regular sunlight via the photothermal effect, and it can be directly reused without noticeable capacity fading. An "easy-to-assemble-at-household" prototype device with 35 g of the dry hydrogel was tested outdoors under field conditions and delivered 20 g of fresh water within 2.5 h under natural sunlight. It is estimated that the material cost of making such a device to supply minimum daily water consumption for an adult (i.e., 3 kg) is only $3.20 (USD). This type of atmospheric water generator (AWG) is cheap and affordable, works perfectly with a broad range of humidity, does not need any electricity, and thus is especially suitable for clean water production in remote areas.