Search Results (13)

This research examines the feasibility of recovering and recycling condensate water, a waste byproduct generated by Atlas Copco ZR315 FF industrial air compressors utilizing oil-free rotary screw technology with integrated dryers. Given the growing severity of global water scarcity, finding alternative water sources is essential for sustainable industrial practices. This study specifically evaluates the potential of capturing and treating compressed air condensate as a viable method for water recovery. The investigation analyzes both the quantity and quality of condensate water produced by the ZR315 FF unit. It contrasts this recovery approach with traditional water production methods, such as desalination and atmospheric water generation (AWG) via dehumidification. The findings demonstrate that recovering condensate water from industrial air compressors is a cost-effective and energy-efficient substitute for conventional water production, especially in water-stressed areas like Morocco. The results show a significant opportunity to reduce industrial water usage and provide a sustainable source of process water. This research therefore supports the application of circular economy principles in industrial water management and offers practical solutions for overcoming water scarcity challenges within manufacturing environments. Full article

This paper presents the first results of a broader study aimed at considering atmospheric water generation as a viable option within sustainable building design strategies. In particular, the focus is on integrated systems in which atmospheric water generator (AWG) machines, in addition to producing water, support HVAC systems. The research focuses on the combined use of two different simulation tools: a commercial tool designed to study the energy balance of buildings and a custom-developed software for AWG modelling. This is the first step of a more complex procedure of software integration that is aimed to provide designers with a method to implement AWGs in the design process of buildings, both residential or industrial. This preliminary procedure is applied to a case study concerning the link between an advanced integrated AWG and a building housing inverters and transformers that belong to a photovoltaic field. The scope of the integration consists in enhancing the energy sustainability of atmospheric water intended for hydrogen production and panel washing by means of the dry and cold air flux that comes from the cycle of vapour condensation. The results highlight the potentialities of the integrated design, which includes AWGs, to enhance the final efficiency of sustainable housing. In particular, the joint action of the simulation tools used in this study provides insights about the possibility to reduce the size of traditional chiller that serve the building by an order of magnitude, and to achieve an energy saving of 29.8 MWh a year. Full article

This research investigated the suitability of air-to-water generator (AWG) technology to address one of the main concerns in green hydrogen production, namely water supply. This study specifically addresses water quality and energy sustainability issues, which are crucial research questions when AWG technology is intended for electrolysis. To this scope, a reasoned summary of the main findings related to atmospheric water quality has been provided. Moreover, several experimental chemical analyses specifically focused on meeting electrolysis process requirements, on water produced using a real integrated AWG system equipped with certified materials for food contact, were discussed. To assess the energy sustainability of AWGs in green hydrogen production, a case study was presented regarding an electrolyzer plant intended to serve as energy storage for a 2 MW photovoltaic field on Iriomote Island. The integrated AWG, used for the water quality analyses, was studied in order to determine its performance in the specific island climate conditions. The production exceeded the needs of the electrolyzer; thus, the overproduction was considered for the panels cleaning due to the high purity of the water. Due to such an operation, the efficiency recovery was more than enough to cover the AWG energy consumption. This paper, on the basis of the quantity results, provides the first answers to the said research questions concerning water quality and energy consumption, establishing the potential of AWG as a viable solution for addressing water scarcity, and enhancing the sustainability of electrolysis processes in green hydrogen production. Full article

The water crisis is currently affecting billions of people. To mitigate the issue, unconventional water sources should be taken into account. Among them, atmosphere is a promising possibility, but it is still considered a novel source, and more studies, based on real results concerning the behaviour of the Atmospheric/Air-to Water Generator (AWG) systems, also known as Atmospheric Water Harvesting (AWH) systems, are needed to prove the water extraction sustainability. The current research work describes the real application of an integrated AWG system, based on a thermodynamic reverse cycle, designed to extract water from air and take advantage of the other useful effects of the cycle at the same time. The integrated machine was placed in Dubai, in a worker village, and tested. The machine is able to provide, at the same time, with the same energy consumption, water, heating and cooling energy. On the basis of onsite measurements, calculations about the efficiencies, using the Water Energy Transformation (WET), plastic savings, due to bottled water avoidance, and economic sustainability were carried out. The work answers to research questions concerning the potentiality of integrated systems in Heating Ventilation Air Conditioning (HVAC) plants revamping, the economic sustainability of water extraction from air and the lack of tests on real AWG machines of thousand-litre production capability (large size). Full article

The scarcity of useable water is severe and increasing in several regions of the Middle East, Central and Southern Asia, and Northern Africa. However, the earth’s atmosphere contains 37.5 million billion gallons of water in the invisible vapor phase with fast replenishment. The United Nations Convention to Combat Desertification reports that by 2025 about 2.4 billion people will suffer from a lack of access to safe drinking water. Extensive research has been conducted during the last two decades to develop nature-inspired nanotechnology-based atmospheric water-harvesting technology (atmospheric water generator, AWG) to provide clean water to humanity. However, the performance of this technology is humidity sensitive, particularly when the relative humidity (RH) is high (>~80% RH). Moreover, the fundamental design principle of the materials system for harvesting atmospheric water is mostly unknown. In this work, we present a promising technology for solar energy-driven clean water production in arid and semi-arid regions and remote communities. A polymeric electrospun hybrid hydrogel consisting of deliquescent salt (CaCl₂) and nanomaterials was fabricated, and the atmospheric water vapor harvesting capacity was measured. The harvested water was easily released from the hydrogel under regular sunlight via the photothermal effect. The experimental tests of this hybrid hydrogel (PAN/AM/graphene/CaCl₂) demonstrated the feasibility of around 1.04 L of freshwater production per kilogram of the hydrogel (RH 60%). The synergistic effect enabled by photothermal materials and deliquescent salt in the hydrogel network architecture presents controllable interaction with water molecules, simultaneously realizing efficient water harvesting. This technology requires no additional input of energy. When considering the global environmental challenges and exploring the available technologies, a sustainable clean water supply for households, industry, and agriculture can be achieved from the air using this economical and practical technology. Full article

Due to the growing issues related to water scarcity and pollution, water extraction from gaseous mixtures, such as atmospheric air, or fumes from combustion, is acquiring increasing importance. Nevertheless, one of the main concerns is the energy consumption that affects the use of any kind of Air(/Gas) to Water Generator (AWG). Referring specifically to water extraction from humid environmental air, AWG behaviour depends upon the air thermo-dynamic conditions and thus upon weather data. To evaluate the water extraction energy efficiency, two interesting tools can be applied: the WET (Water Energy Transformation) indicator, concerning the specific AWG machine behaviour, and the MHI (Moisture Harvesting Index), focused on climate suitability evaluation. Those tools require the knowledge of weather data to be applied. When hourly data for the entire year are available, the application of these tools leads to reliable results. However, in many cases, only average climatic data are available. Today, there are no indications about the reliability of results coming from the use of those less accurate data sets: the research aims to provide a preliminary assessment of the conditions under which average climatic data can be employed without losing meaning. This target was pursued by calculating WET and MHI with three different data sets and five meaningful climate examples. By comparing results, it was possible to provide indications about the most suitable use of average data. Full article

The water harvesting potential of atmospheric water generators (AWGs) in high-altitude semiarid regions can be diminutive relative to the water generation capacity. Operational parameters for the dehumidification process can be augmented to increase atmospheric water in the defined zone available for harvesting. In this paper, the feasibility of augmenting the microclimates of AWGs at the point of air extraction through an evaporative cooling system (ECS) was investigated. Water yield and capacity utilisation were measured from two AWGs piloted on a plant in Ga-Rankuwa, South Africa. This was implemented between December 2019 and May 2021. The study revealed that although the ECS did impact the operating parameters through decreasing temperature and increasing relative humidity (p < 0.05), variance in water yield was not significant (p > 0.05). Capacity utilisation of the AWGs remained below 50% after augmentation. Cooling efficiency of the ECS ranged between 1.4–74.5%. Energy expenditures of 0.926 kWh/L and 0.576 kWh/L for AWGs 1 and 2 were required under pristine conditions, respectively. Under the modified conditions, energy expenditure decreased to 0.855 kWh/L for AWG 1, but increased/L to 0.676 kWh for AWG 2. ECS is deduced to not be a feasible intervention for augmenting water harvesting potential for AWGs in this semiarid zone. Full article

Globally, multiple efforts are being made to develop active atmospheric water generation (AWG) or atmospheric water extraction (AWE) systems, particularly using direct air-cooling technology to produce water from ambient air. However, this legacy technique is highly energy-intensive; it can only be operated when the local dew point is above the freezing point of water, and does not scale to create enough water to offer solutions for most industries, services, or agriculture. Liquid-desiccant-based AWG methods show promising performance advantages, and offer a versatile approach to help address the thermodynamics, health risks, and geographic constraints currently encountered by conventional active AWG systems. In this study, we performed a techno-economic analysis of a liquid-desiccant-based AWG system with a continuous operating style. An energy balance was performed on a single design point of the AWG system configuration while using a LiCl liquid desiccant loaded with multiwalled carbon nanotubes (MWCNTs). We showed that the MWCNTs can be doped in LiCl for effective heat transfer during water desorption, resulting in lowering of the sensible heat load by ≈49% on the AWG system. We demonstrated that the specific energy consumption (SEC) can currently be obtained as low as 0.67 kWh per US gallon, while changing the inlet desiccant stream concentration of MWCNT-doped LiCl under the given conditions. While the production cost of water (COW) showed a significant regional dependency, economic analysis revealed that water can be produced at a minimum selling price of USD 0.085 per US gallon, based on the 2021 annual average wholesale electricity cost of USD 0.125 per kWh in the U.S.A., thereby providing a strong foundation for future research to meet desirable and competitive water costs by 2026, but before 2031. Full article

Due to water scarcity, in the last few decades, air-to-water generator (AWG) technology, whose useful effect is the extraction of water from air, has been improved. In particular, in the last few years, advanced AWG integrated systems have been developed. Such systems permit, not only to condense water from air, but also the smart use of the by-side effects of the process in order to partially or totally cover the heating ventilation air conditioning (HVAC) needs of a building. Presently, there are no evaluation tools that permit a complete comparison among AWG machines, taking into account all the useful effects that can be obtained at the same time and with the same energy input. The current work, starting from the need for such a tool, proposes a global index whose formulation considers all useful effects of an integrated system, the energy required to obtain them, and the integration degree of the machine. The index translates into a single number the system global efficiency, by means of a particular combination of existing efficiency indicators. In its extended formulation, it can be applied, not only to AWGs, but also to other HVAC integrated systems, as well as to combinations of non-integrated and integrated solutions. In addition to equations, the paper provides calculation examples and a case study in order to show the practical application and advantages of GEI. Full article

Technologies for obtaining drinkable water are becoming more important as global water consumption steadily increases and climate change progresses. One possibility for obtaining water is the extraction of water vapor from ambient air by means of air water generators (AWG). Previous studies in the field of AWG have mainly dealt with the condensation of humidity on cold surfaces with a cooling system or with absorption and thermal desorption. In this paper, another possibility for AWG is investigated, specifically AWG using absorption and reverse osmosis. For this purpose, models have been set up for an absorber operated in countercurrent and reverse osmosis membrane modules operated in co-current and countercurrent. With these models, simulations with different boundary conditions were then carried out using the programming language Python. The simulations have shown that the reverse osmosis membrane modules operated in countercurrent generally have a lower energy demand and require fewer reverse osmosis stages than those operated in co-current. Full article

Photovoltaic panel efficiency can be heavily affected by soiling, due to dust and other airborne particles, which can determine up to 50% of energy production loss. Generally, it is possible to reduce that impact by means of periodic cleaning, and one of the most efficient cleaning solutions is the use of demineralized water. As pauperization of traditional water sources is increasing, new technologies have been developed to obtain the needed water amount. Water extracted from the air using air to water generator (AWG) technology appears to be particularly suitable for panel cleaning, but its effective employment presents issues related to model selection, determining system size, and energy efficiency. To overcome such issues, the authors proposed a method to choose an AWG system for panel cleaning and to determine its size accordingly, based on a cleaning time optimization procedure and tailored to AWG peculiarities, with an aim to maximize energy production. In order to determine the energy loss due to soiling, a simplified semiempirical model (i.e., the DIrt method) was developed as well. The methodology, which also allows for energy saving due to an optimal cleaning frequency, was applied to a case study. The results show that the choice of the most suitable AWG model could prevent 83% of energy loss related to soling. These methods are the first example of a design tool for panel cleaning planning involving AWG technology. Full article

In this work, an atmospheric water generator (AWG) system called the medium-scale AWG (MSAWG) was designed, fabricated, and tested in Universiti Sains Malaysia (USM) under the outdoor tropical climate conditions of Malaysia to investigate the amount of fresh water production in successive periods of 24 h. The MSAWG consisted of 18 thermoelectric cooler (TEC) units, 18 internal finned heat sinks, 18 external finned heat sinks, 18 direct current (DC) cooling fans, an air-conditioner mesh air filter, and an axial ventilation fan. It was found from the results that the hourly values of water production of MSAWG were proportional to the hourly rates of relative humidity, but they were inversely affected by the corresponding hourly values of the ambient temperature. Night-time and early morning were the most effective times to produce the highest amount of fresh water from Malaysia’s atmosphere using MSAWG, as the increase in the rates of relative humidity and the decrease in the values of ambient temperature occurred over these periods. Based on the varied hourly rates of relative humidity with the ranges between the minimum rate of 55% and maximum rate of 85%, an equation of Y = 0.2285X + 36.675 with R² of 0.9404 was achieved from the 48 h experimental work to estimate the water production of MSAWG in Malaysia, where Y and X were indicated as the rate of relative humidity and the value of water production, respectively, in this equation. In conclusion, the MSAWG produced a consecutive cumulative water volume of 3.432 and 6.997 L experimentally in the periods of 24 and 48 h, respectively. The estimated cost per liter for MSAWG was USD 0.466. Some water quality parameters of the fresh water produced by MSAWG were analysed in the laboratory, which showed that they met the World Health Organization (WHO) drinking water standards. Therefore, MSAWG can be employed as a sustainable alternative to generate annual daily fresh water from Malaysia’s tropical atmosphere and aid in mitigating the problem of unpredicted water shortage in the country. Full article

Water extraction from air, based on reverse cycle systems, is becoming a technology more and more diffused and various models of air to water generators (AWG) are now available, all claiming the best efficiency. To date, there is not a standard indicator stating energy efficiency for AWGs, neither in the literature nor in technical practice. The only evaluation parameter, that can be found is a sort of specific energy consumption (SEC) without any clear indications about the involved calculation terms, definition of hypotheses, or environmental conditions. The current work is a first proposal of an indicator to standardise the AWG efficiency evaluation. The indicator is called WET (Water Energy Transformation); it states water production as a useful effect of an AWG machine and calculates its energy performance with an approach similar to COP (Coefficient of Performance) and EER (Energy Efficiency Ratio) evaluation. The indicator is meant to be a normalised tool that permits comparing different AWG machines, but it is also the first part of a wider study, currently under development that is oriented to obtain a global index formulation that combines WET itself, EER and COP, and it is intended for a comprehensive evaluation of all the useful effects of a reverse cycle in integrated machines, in compliance with the current efficiency evaluation approach. The current paper presents the WET equation, with a discussion about involved terms, a set of normalised calculation conditions and some application examples, including a comparison with SEC. Full article