Atmospheric Water Generator Research Articles

Performance Assessment of Atmospheric Water Generators: A Review of Evaluation Tools and Proposal for a Novel Advanced Global Evaluation Index for HVAC–AWG Hybrid Solutions

In the context of an increasing water crisis and rising energy consumption, an integrated approach to plant design and improvement can be highly effective. Specifically, the use of advanced multipurpose Atmospheric Water Generator (AWG) machines, integrated into existing or new HVAC systems, can improve efficiency while simultaneously extracting atmospheric water. However, hybrid plant configurations, which encompass both integrated and traditional solutions, can be difficult to assess. This paper presents a brief review of the most widely used AWG evaluation tools and proposes a new index, called AGEI, designed to address the knowledge gap in evaluating hybrid plants from an efficiency perspective. The paper shows how this index provides results that more accurately reflect the real efficiency of hybrid plant configurations compared to the Global Evaluation Index (GEI), which is the only existing tool addressed to the evaluation of integrated multipurpose machines. The work is complemented by the application of AGEI to three complex hybrid plant configurations, two of which include a bottling system supplied by desalination for drinking water production. The index is straightforward and requires only knowledge of the useful effects produced by the analysed plant and their corresponding efficiency indicators.

Efficiency assessment of integrated Atmospheric Water Generators (AWGs) using the Global Evaluation Index (GEI): a case study

Abstract Atmospheric water can represent a potential solution to address the global water scarcity issue affecting an increasing proportion of the population. Two of the main issues related to its production and use are represented by the energy consumption and the need of meaningful quantities of liquid extracted per day. They can be addressed through an integrated approach, which consists in employing a single process to achieve more than one useful effect, with the same energy consumption. In this perspective, in the last decade, advanced Atmospheric Water Generators (AWGs) have been developed. Such a kind of machines are based on a compression reverse cycle and, besides a considerable water production (up to thousands of litres per day) are capable to exploit all the useful effects of the said cycle, consuming about the same energy of the only water extraction. The global evaluation index (GEI) has been developed to provide a metric for the efficiency evaluation of integrated solutions. In the research literature there is a lack of examples of GEI application. The current paper aims to provide a first fulfilment of the research gap, providing a case study where the index is applied and discussed. In particular, the analysis concerns an integrated AWG connected to an electrolyser and a photovoltaic field for green hydrogen production. The GEI is employed to carry out a comparison between pre and post configuration of the plant. Results underline the index capability to provide an efficiency evaluation by means of a single number.

Energy Management System for a Smart Grid Including Atmospheric Water Generation

Abstract The aim of this paper regards the development of an Energy Management System (EMS) for a smart grid including water extraction from atmospheric humid air. Special attention is focused on the water demand satisfaction with different generation systems and storage technology. The main innovation of this analysis is the application of the EMS tool, usually developed for energy production machines, to optimize, in real-time mode, their integration with a water-collection system. Starting from component models development and validation, the results obtained with the EMS were successfully compared with a standard management approach showing the cost benefits and the related impact on the environmental side. Moreover, different layouts were analyzed to show the benefits due to component integration, especially for the storage systems. In details, the integration of different technologies focusing special attention of energy storage was able to produce important benefits for exploiting renewable sources. So, this approach, based on an EMS tool, was demonstrated as a promising application for energy transition process, considering the importance and flexibility of optimized air-to-water generation systems (AWGs).

Interactions between volatile air pollutants and atmospheric water production – Effects of chemical properties, mechanisms, and transfer processes

Regional water scarcity is among the most urgent challenges of global climate change. Atmospheric water harvesting is a promising method to mitigate these challenges, and the atmospheric water generator (AWG) is already an established technology. Although this method can produce over 10,000 L of water per day, the water's quality has not been studied in depth. Air pollutants, especially volatile organic compounds (VOCs), are potential contaminants of water produced from air. We evaluated the chemical and physical parameters of different VOCs that might influence their ability to be transferred from air to AWG water. Our findings strongly suggest that the ability to form hydrogen bonds is a key factor in this transfer. Henry's law constant, polarity, and intrinsic solubility were the main predictors of a VOC's transfer to AWG water. Hence, aliphatic or aromatic compounds (such as benzene or octane) were not found at significant concentrations in AWG water (e.g. above WHO guidelines), whereas ammonia and alcohol compounds were. This should be taken into consideration when analyzing potential contaminants in harvested atmospheric water. The condensation process itself was also found to enhance the transfer of VOCs into water droplets, and higher relative humidity (%RH) also increased VOC transfer. Gas-phase infrared spectrum analysis of VOCs at different %RH revealed possible interactions between water vapor and specific VOCs in the air. However, our main conclusion from this study is that VOC transfer from the air into AWG water occurs predominantly via dissolution in the condensed droplets, and strongly depends on their chemical properties of polarity and hydrogen-bond formation.

Development of performance indicator for metal-organic frameworks in atmospheric water harvesting

This study aims at developing a new set of performance indicators for atmospheric water generation (AWG) via metal organic frameworks (MOFs). Several field studies report specific setup paired with particular MOF but often lack evaluation on a common benchmark for AWG which is focused in this study. The article lays down a stepwise procedure by extracting information from in-vivo material characteristics such as water adsorption isotherms and kinetics, to model MOF behaviour in AWG, and produce four novel quantifiers to describe the complete systems performance in terms of uptake, thermodynamics, surface projection, and kinetics. A model MOF-801 AWG has also been evaluated for a proof of concept. Furthermore, three independent water adsorption experiments on MOF-801 from the literature are compared based on as-developed indicators and ranked according to the performance of the system.

Waste heat-driven water generator with optimized multi-cycle strategy for high water yield

Water scarcity and energy crisis have recently become two severe global problems. Low-grade waste heat, a substantial byproduct of energy consumption, promises to provide safe water by driving sorption-based atmospheric water harvesting (SAWH) device. Herein, a low-grade waste heat-driven atmospheric water generator (LWG) is constructed with rapid kinetics at the system level. Solely in 3 h, the device obtains 1.766 g g−1 of water productivity and up to 98 % of water recovery ratio driven by 120 °C of waste heat. Further, an optimized multi-cycle operation strategy is proposed to guide LWG's daily water harvesting, enabling it to predictably obtain over 15 kg m−2 day−1 water productivity by maximizing systemic sorption and desorption-condensation rates. The strategy not only is widely suitable for all SAWH devices, but also provides a universal optimization guideline for sorption-based dehumidification, thermal storage, and electric thermal management.

Optimization and performance evaluation of a novel absorption-based atmospheric water generator system for enhanced energy efficiency

Providing potable water poses a severe and chronic challenge for the human race. Conventional desalination systems are only feasible in large-scale production, requiring significant energy and a source of feeding water. Atmospheric water harvesting is a decentralized water production method that uses air humidity as a renewable water source. This technique holds promise for providing water even in hard-to-reach regions with no source of liquid water. However, the feasibility of this method declines in arid or semi-arid climates. In this paper, a novel absorption-based atmospheric water generator is proposed to improve the feasibility and cost-effectiveness of this technique to make it a viable method for producing fresh water, even in arid regions. The system is modeled using EES software to explore the effects of seven adjustable parameters on its performance. Subsequently, the modeled system is transferred into MATLAB through the utilization of artificial neural networks. A tri-objective optimization is then carried out using the genetic algorithm approach. The optimized system can produce 14016m3/year of fresh water, with a levelized cost of approximately 33.72$/m3, operating under hot and arid weather conditions (27°C and 25% RH). The data acquired from the system’s performance parameters is leveraged to derive correlations that are used to determine the system’s performance based on the input weather data. These correlations allow for the assessment of system feasibility across various regions and serve as a valuable shortcut in modeling similar systems for future research.

Atmospheric water generator: design for rural zones with low and medium humidity level

Water shortage is one of the major issues in the world. The consequences can impact negatively on the develop of a location. Puno is an arid region located in Peru. There have been different problems related to water shortage in recent years. Some communities use a waterhole filled by precipitation as a source of water. This is usually far from their communities, then they have to transport manually buckets of water by waking. In this paper, we establish a design procedure of an atmospheric water generator (AWG) located at Puno with a capacity of 40L per day in order to deal with the water shortage. Current AWGs are designed for locations with favorable climatic conditions as high relative humidity (RH). However, they wouldn't be able to operate in dried seasons as at Puno with RH under 25%. An adsorption process is implemented as an additional module in order to compensate the low ambient temperature and RH during the worst climatic conditions from June to August. An analytic model of dehumidification by a heat exchanger was developed in order to quantify influence of parameters as climatic conditions and mass fluxes. Results showed that the design is capable to produce water during all the variable climactic conditions over the year. Numerical simulations of the analytic model indicated that the system can produce water by direct cooling in most months without the support of adsorption process.

Mass transfer experimental investigation and optimisation analysis of zeolite-coated fin-tube heat exchangers in a novel concept of an atmospheric water generator designed for arid climatic conditions

Four zeolite-coated fin-tube heat exchangers were manufactured and experimentally tested under steady-state arid climatic conditions to analyse the influence of inlet air conditions on the mass transfer performance properties. These tests involved nine operational states with ambient air temperatures ranging from 15 °C to 35 °C and humidity ratios ranging from 5 g/kg to 10 g/kg. The obtained experimental results were utilised to analyse and optimise the potential mass transfer performance of a novel atmospheric water generator (AWG) concept explicitly designed for arid climatic conditions. Firstly, the influence of the adsorption/desorption time duration on the mass transfer performance parameters was investigated. The results demonstrated the positive effect of the process intensification: the moisture transferred during one adsorption/desorption cycle decreased slightly by an average of 6 %, while the duration time of both processes decreased considerably by an average of 32.4 %. Secondly, an annual simulation analysis was conducted to analyse the potential mass transfer performance of the presented AWG concept under the arid climatic conditions of Riyadh and Tamanrasset. The results revealed that shortening the entire cycle increased the annual moisture transferred from 893 kg to 1518 kg for Riyadh and from 899 kg to 1500 kg for Tamanrasset climatic conditions.

Eco-friendly atmospheric water generation: A novel desiccant-based variable pressure humidification-dehumidification system

This study introduces a zero-brine discharge approach, eliminating the necessity for continuous seawater input and brine disposal—major drawbacks in traditional desalination methods. This research’s core is a humidification-dehumidification (HDH) system operating under variable pressures, significantly boosting efficiency. The system comprises two synergistic components: a variable-pressure HDH unit and a desiccant-based moisture extractor utilizing a lithium chloride solution. After freshwater is extracted, the concentrated desiccant cycles through the moisture extractor to absorb atmospheric water vapor, diluting it for reuse and thus completing the desiccant loop. The heat and mass transfer processes were scrutinized through mathematical modeling, and parameters for maximizing the Gain Output Ratio (GOR) were optimized. The results underscore the system’s capacity for sustainable, efficient freshwater production. This methodology offers a feasible solution to challenges in desalination and significantly contributes to alleviating global water scarcity, particularly in coastal areas. Further analysis shows that systematic optimization of key parameters, such as pressure ratios and desiccant temperatures, considerably improves performance metrics. Adjusting the pressure ratio from 1.22, where the GOR peaks at 2.44, to 1.56 directly impacts system efficiency. Modulating the maximum desiccant temperature at an optimal pressure ratio of 1.25 reveals that the GOR can increase from 1.635 at 0.7 to 2.44 at an effectiveness of 0.8. Optimized manipulation of these parameters can potentially enhance the GOR by up to 50% and improve mass transfer efficiency by about 20% within the HDH process.

Thermal modelling and performance evaluation of a low-grade heat-driven sorption-based atmospheric water generator under various weather conditions

Thermal modelling and performance evaluation of a low-grade heat-driven sorption-based atmospheric water generator under various weather conditions

Theoretical and experimental study of atmospheric water generation employing desiccant materials in a solar-powered single slope apparatus with internal reflectors

Theoretically and experimentally, this study examined how clean water may be generated from ambient air in Kirkuk City, Iraq. As desiccant materials, blue silica gel and a composite substance consisting of silica gel and calcium chloride were utilised, and a single-slope device consisting of two similar portions was used. The process entails humidity adsorption at nighttime and humidity desorption and vapour condensation during the daytime to generate water droplets. The regeneration process's theoretical outcomes were anticipated by employing the 4th-order Rung Kutta approach in MATLAB, and a price analysis was used to find out the price of producing freshwater. The findings demonstrated that the silica gel's theoretical cumulative productivity was significantly higher than its collected one. In contrast, the experimentally measured silica gel temperature was higher than the predicted one. Also, it was found that the adsorption rate, coefficient of mass transfer, as well as productivity of Silica gel, were higher than the composite material, and the yearly cost of generating water utilising silica gel and composite material was 2.54 $/L and 2.49 $/L, respectively. The accumulated water productivity using silica gel and composite material for the average results of November was 112 g/m2 and 73 g/m2, respectively. More significant water production levels may be attained if this procedure is applied in another area with high relative humidity, and the price of generating water will be significantly lower in this scenario.

Design and Fabrication of Setup for Harvesting Water from Atmospheric Air- A Review

In numerous nations like India, accessing water resources for irrigation or other needs, particularly in arid regions, poses a significant challenge. Water scarcity is a prevalent issue worldwide, often stemming from insufficient rainfall. Conversely, in highly humid locales such as coastal areas, water can be procured through condensing atmospheric water vapour. This paper introduces a method for developing a water condensation system utilizing thermoelectric cooling technology. The system comprises cooling elements, a heat exchange unit, and an air circulation mechanism. Powered by a solar cell panel unit with a substantial output, the cooling elements are regulated through a control circuit. An Atmospheric Water Generator, a device capable of converting atmospheric moisture directly into potable water, operates on the principle of latent heat to transform water vapour molecules into water droplets. Although introduced earlier, it remains relatively uncommon in India and other regions. However, given the contemporary emphasis on renewable energy sources, its potential applications are considerable. Key words :Water condensation, Thermoelectric peltier, Dew condensation (latent heat), Solar energy, AWGs.

Modeling and analysis of thermoelectric atmospheric water generation in the economic city of Iraq

Modeling and analysis of thermoelectric atmospheric water generation in the economic city of Iraq

Autonomous Atmospheric Water Harvesting over a Wide RH Range Enabled by Super Hygroscopic Composite Aerogels.

Sorption-based atmospheric water harvesting (SAWH) offers a sustainable strategy to address the global freshwater shortage. However, obtaining sorbents with excellent performance over a wide relative humidity (RH) range and devices with fully autonomous water production remains challenging. Herein, magnesium chloride (MgCl2) is innovatively converted into super hygroscopic magnesium complexes(MC), which can effectively solve the problems of salt deliquescence and agglomeration. The MC are then integrated with photothermal aerogels composed of sodium alginate and carbon nanotubes (SA/CNTs) to form composite aerogels, which showed high water uptake over a wide RH range, reaching 5.43 and 0.27kg kg-1 at 95% and 20% RH, respectively. The hierarchical porous structure enables the as-prepared SA/CNTs/MC to exhibit rapid absorption/desorption kinetics with 12 cycles per day at 70% RH, equivalent to a water yield of 10.0 L kg-1 day-1. To further realize continuous and practical freshwater production, a fully solar-driven autonomous atmospheric water generator is designed and constructed with two SA/CNTs/MC-based absorption layers, which can alternately conduct the water absorption/desorption process without any other energy consumption. The design provides a promising approach to achieving autonomous, high-performance, and scalable SAWH.

Energetic analysis and economic viability of active atmospheric water generation technologies

Water scarcity is a growing global and systematic problem in regions with low groundwater availability. Atmospheric water generation (AWG) technologies are an innovative solution to the water shortage problem, as atmospheric water vapor is a readily available resource even in arid regions, with the drawback of high energy consumption. In this paper, the viability of AWG technologies on an energy and economic level is investigated by thermodynamic modeling of three main active AWG systems consisting of cooling condensation, adsorption and absorption processes. A location analysis model is developed to evaluate the performance based on representative weather data of temperature, pressure and relative humidity over a period of one year to account for seasonal shifts and daily variations in climatic conditions. The specific energy consumption kWh/kg, water production trend and total specific cost are calculated for each technology. Water production by seawater desalination at the nearest coastline and transportation to the site by tanker truck, as well as bottled water prices, are used as benchmarks to assess economic viability. The results show that active AWG systems can only be an economically viable alternative if the water consumption site is relatively far from the coast or other water-rich regions and low electricity costs are available (distance >600 km, electricity price <0.10 US$/kWh). Compared to bottled water, all AWG technologies are in a competitive price range. Absorption systems have an energy efficiency advantage over conventional cooling condensation and adsorption systems (cooling condensation: average 0.42 kWh/kg; absorption: average 0.38 kWh/kg; adsorption: average 1.16 kWh/kg), but require a higher degree of process and plant design development. However, because of the high fluctuation in water production, atmospheric water generation technologies should be considered as a complementary supply to conventional water sources.

EXPERIMENTAL STUDY OF A SOLAR-POWERED ATMOSPHERIC WATER GENERATOR

Drinking water availability is a major trouble in some regions in Libya because of the lack of water sources. The atmospheric water generator (AWG) is one of the alternative techniques for freshwater recuperation from the atmosphere, which condensed the moisture content of water vapor from the air directly. This paper affords an experimental study of AWG in Libyan climate conditions . In this study, a transportable AWG was experimentally studied. The effect of varied humidity, inlet airflow, and temperature, on AWG productivity and the energy required. The amount of generated water increases with the increase in temperature, humidity, and inlet airflow, reaching its peak (16.9 ml/(m3 of air)) at 32.9 °C and 49 % humidity, and it’s lowest value (6.85 ml/(m3 of air)) 29.5°C and 55 % humidity. The maximum production efficiency of AWG was 93.430% at temperature 32.9 °C, humidity 49% , airflow 76.392 m3/hr, and 1048.5 Watt .

Assessing the feasibility of nighttime water harvesting from solar photovoltaic panels in a desert region

Photovoltaics has emerged as a crucial and progressively significant contributor to renewable energy generation. Nevertheless, its effectiveness is limited to daylight hours when sunlight is available. This research paper presents an approach to promote dual usage of solar panels beyond daytime operations to facilitate water production. An AWGPV (Atmospheric water generation on PV modules) system is built and operated for nearly a year. During this period, several prototypes were built to produce up to 2.5 L/panel per day without optimizing the energy consumed during direct cooling. A techno-economic assessment was done for the prototype AWGPV system. The prototype system consisting of 3 AWGPV panels connected to the grid was able to produce water at 33 USD cents per liter in Dubai, UAE. If the electricity for direct cooling is reduced, the cost of water can be reduced further. The results point to new avenues to explore methods for reducing the electricity consumption for cooling for achieving further cost reduction. A parameter n-MHI (night Moisture harvesting index) is introduced to evaluate the feasibility and energy demands of harvesting atmospheric moisture through direct cooling. Through a climate-based analysis of various locations, the global potential of this process is explored. The collected water can be used for dust cleaning of solar panels, agrophotovoltaic systems, and other applications where water and electricity generation needs to be decentralized.

CFD Analysis of Refrigerator Integrated with Atmospheric Water Generator

This Research article discuss about the study of performance analysis. This system is a combination of refrigerator and Atmospheric Water Generator (AWG). The purpose behind integrating two devices is to get benefit of both products together, refrigerator will act as a domestic refrigerator plus the atmospheric water system will generate the fresh distilled water to drink. This system is designed to generate a water of 20 liters per day. Also, it is designed in such a way that, this AWG can attach with various capacity is the refrigerator. Performance evaluation of this system is done with the help of computational fluid dynamics. Fluent module is used in ANSYS software. Various levels of parameter are evaluated, variables considered in the study were Relative humidity, velocity of air in AWG heat exchanger, and temperature of air. The output parameters evaluated like water generation capacity of AWG, Coefficient of Performance (COP) of AWG and refrigerator and heat exchanger efficiency. The results of CFD shows positive results as per design. 24th case has given highest COP 1.26. General, range of COP lie between 1.127 to 1.260. COP of Standard Refrigerator remain between 1.437 to 1.593. Also, it means COP of other two cases are more. As far as COP of Refrigerator concern, COP with AWG is heist i.e. 1.91. But it cannot be clearly state that, COP with AWG is more than COP without AWG.

Proof of Concept of the Regeneration Part in a Novel Desiccant-Based Atmospheric Water Generator

Proof of Concept of the Regeneration Part in a Novel Desiccant-Based Atmospheric Water Generator