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Condensation of water vapor available in atmospheric air can be considered as a solution for water scarcity problem. In this paper, a comprehensive thermodynamic analysis of water production from humid air using thermoelectric coolers (TECs) is presented. The system consists of a number of thermoelectric coolers, a fan to supply the required air fl...
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Water scarcity has been a major problem of Kathmandu Metropolitan City (KMC).
Different interventions are being attempted to solve this problem including the highly
discussed Melamchi Drinking Water supply project. Thus, so rainwater harvesting
(RWH) could be a promising approach to satisfy water to some extent.The study has
aimedto assess the...
![Fig.4 and time, obtains the following algebra [47] :](publication/349080479/figure/fig2/AS:988292610785281@1612638728806/and-time-obtains-the-following-algebra-47_Q320.jpg)
Underground condensation water production system is a low capacity water harvesting method that is suitable for hot and humid climate regions. In this method, the hot and humid airflow is directed to the buried pipes in the ground and, the air is gradually cooled down and the vapor contained therein appears as droplets of water on the pipe surface....
Atmospheric water vapor is ubiquitous and represents a promising alternative to address global clean water scarcity. Sustainably harvesting this resource requires energy neutrality, continuous production, and facility of use. However, fully passive and uninterrupted 24-hour atmospheric water harvesting remains a challenge. Here, we demonstrate a ra...
Background Water scarcity restricts agro-pastoral farming systems, and thus the development and economic growth of arid environments' communities, which face several challenges that are interconnected with water scarcity including land degradation, low productivity, and food insecurity. Providing sustainable water harvesting technique (WHT) is one...
Citations
... Zhang et al., analyzed temperature and humidity distribution inside a dehumidification runner and the heat and mass transfer coupling relationship [14]. Hao and Eslami analyzed the relationship between dehumidification capacity and energy consumption under different influencing factors [15,16]. In order to improve the efficiency of water intake, research has recently been carried out in the areas of solar air intake and semiconductor refrigeration water intake. ...
In this paper, by analyzing the heat and mass transfer characteristics of the dehumidification runner microelement channel of a drinking water emergency extraction vehicle, a mathematical model of heat and mass transfer in the water intake process is established, and the influence of the runner parameters (adsorbent thickness, regeneration angle, rotation speed) and air parameters (treatment air temperature/humidity, regenerated air temperature/humidity) on the water intake characteristics is mainly studied. Water extraction experiments are carried out in arid desert areas and humid island environments. The test results showed that compared with the calculated data, the deviations in the temperature and humidity of the treated air outlet were 3.03% and 4.14%, respectively, and the deviation value of the water intake was 8.23% when the moisture content of the inlet air was 2 g/kg.
... They found that maximum produced water is about 400 litre per month in tropical climates with specific energy consumption of 3 kWh/L. AWH by TEC Technology with water productivity and energy consumption were analysed in many studies; 1.6 L/day water capacity and 61 Wh power input was reported [19][20][21][22][23]. Xiaolong Xu et al. used the radiative cooling principle for a house cooling with storage tank and loop heat exchanger [24]. ...
... It is estimated that nearly 52% of the world's population will live in water-stressed regions by 2050. Unfortunately, only about 2.5% of the water on earth is drinkable, and this rate is decreasing day by day due to increasing environmental pollution and climate change [1,2]. Treatment of wastewater for clean drinking water or obtaining freshwater from seawater are some suggested solutions to reduce the gap between the water supply and demand, but wastewater treatment and desalination of seawater are quite costly with today's technology [3]. ...
The purpose of this study is to improve the water harvesting capacity of the traditional wire mesh from the fog by modifying its surface using a nature-inspired composite structure consisting of hydrophilic and hydrophobic zones. Hydrophilic zones were obtained by electrospinning or electrospraying of the polyamide 6 (PA6) / chitosan (CH) blend, and similarly hydrophobic zones were attained by electrospraying of polycaprolactone (PCL). The water harvesting capacity of the resulting meshes was tested and compared with each other. The highest water harvesting capacity was achieved with the PA6/CH nanofiber coated wire mesh as 87 mg / cm2/h. This mesh collected twice as much water compared to the uncoated mesh. However, its water collection rate decreased when nanofiber surface reached the saturation level. The addition of hydrophobic PCL particles onto nanofibers reduced the amount of water captured. In this case, the water collection rate of the mesh continued to increase.
... AWGs can be further classified as condensation and sorption types [5]. The condensation type AWG uses vapour compression cycle (VCC) [6][7][8][9][10][11] or thermoelectric cooling (TEC) [12][13][14][15][16][17][18][19] to cool down a surface temperature of a heat exchanger below the dew point temperature of the process air. The weak point of condensation AWGs is that the water harvesting process under dry and hot climatic conditions is very energy intensive or even impossible due to very low dew point temperature values (sometimes even negative) [20,21]. ...
In this paper, a novel concept of an atmospheric water generator (AWG) based on desiccant coated heat exchangers (DCHEs) is presented. Two silica gel coated heat exchangers (SGCHEs) and two zeolite coated heat exchangers (ZCHEs) were prepared by coating a desiccant material on the surface of a conventional air-to-water fin-tube heat exchanger. An experimental set-up was built to investigate the performance characteristics of the prepared DCHEs in terms of the moisture removal capacity MRC, the effective duration of the process te, and the total moisture mass transferred during the dehumidification/regeneration cycle MT. The influence of the regeneration hot-water temperature Tw,in on the performance characteristics was also analysed. The experimental results showed that ZCHEs have better performance characteristics under arid climatic conditions than SGCHEs. It was found that the ZCHEs have approximately four times higher value of the moisture transferred during the dehumidification/generation cycle MT compared to the SGCHEs, 10.15 g for the ZCHEs and 2.60 g for the SGCHEs. Moreover, it can be concluded that the influence of the regeneration water temperature Tw,in for ZCHEs is not as critical as for SGCHEs. The experimental results indicated that when the regeneration hot-water temperature Tw,in decreases from 85 °C to 65 °C, the moisture transferred during the dehumidification/regeneration cycle MT for the ZCHEs decreases from 10.15 g to 7.11 g representing a 30% decrease in the system performance, while for the SGCHEs the same decrease in the regeneration hot-water temperature Tw,in causes a significant decrease in the moisture mass transferred during the cycle MT from 2.60 g to 0.85 g, representing a 67% decrease in the system performance.
... The results of their work indicates that between 32 and 66 mlit/h fresh water has been produced by employment of 60 W TEC when the humidity of air is 60% and 80%, respectively. A comprehensive thermodynamic analysis has been accomplished by Eslami et al. (2018) for evaluation of the performance of a solar driven TEC for extraction of water from humid air. In addition, the Outlet sensitivity analysis and optimization have been employed to find the optimum size of the AWG. ...
The drinkable water storages shortage is one of the main obstacles that many societies are envisaged with. In addition, the water content of humid air is known as the main storage of drinkable water for the future. In this paper, the energy and exergy analysis of a solar driven atmospheric water generator which contains an absorption refrigeration cycle coupled to a compound parabolic collector is performed. The mathematical model of the proposed system is developed in MATLAB software. In the solar thermal system provided in this paper, the storage tank is employed for extending the working hours of the system leading to improvement of total water generation rate. Furthermore, the performance of the system is evaluated in various climates included arid, semi-arid and Mediterranean, and for this purpose three cities of Iran named Bandar Abbas, Ramsar and Tehran were selected. Moreover, by comparing the water production in various months during the year, the highest value of water production during the year is held by Bandar Abbas city leading to owning the lowest values of specific power consumption and specific collector area. The maximum rate of water production of proposed system is approximately 400 lit per month in tropical climates with specific energy consumption of 3 kWh/lit. Based on the results of exergy analysis of whole system, the most exergy destruction rate belongs to compound parabolic collector component, therefore, large amount of energy is wasted through compound parabolic collector which can be recovered for generation of chilled water. Moreover, the impacts of geographical and environmental parameters on the energy and exergy efficiencies of the atmospheric water generator are also assessed.
... This system depends on either condensation or sorption [6,7] methods. Condensation methods include active cooling condensation [8], a refrigeration technology, such as vapor compression cycle (VCC or VCR) [9,10], adsorption/absorption chiller [11,12] and thermoelectric cooling (TEC) systems [13][14][15]. VCC can be used either for just water harvesting or for both air conditioning and water harvesting. For air conditioning and water harvesting, normally central cooling systems are used and the condensed water is considered the byproduct of air cooling [16]. ...
... This system was designed considering many parameters such as temperature, humidity, airflow, and pressure. A study of the optimum number of TEC modules and the length of the condensation channel was presented in [11]. In both [12], [13], ON/OFF control systems were developed for dehumidifier systems. ...
... Port B is connected to the ambient air through the thermal resistance of the hot surface fins. The relations between the absorbed heat on the cold side, the emitted heat from the hot side, the temperature difference between cold and hot sides, injected current, and the applied voltage are described by Eq. (9) to Eq. (11). The moist air is fed into the condensation pipe as illustrated in Fig. 7, via a controlled volumetric flow rate source. ...
In this paper, a Thermo-Electric Cooler (TEC) based ambiently adaptive Atmospheric Water Generator (AWG) system is proposed. Due to the advantages of TEC technology, it has been relied upon in the phase of dehumidifying the air flowing in the proposed system as an alternative to other mechanical methods. An AWG cooling control system has been developed based on the proposed algorithm to determine the temperature that achieves the highest productivity, which depends on the change in thermal load by changing the airflow, which keeps the temperature of the humid air inside the system below the Dew Point (DP) temperature at varying ambient conditions for sustainable water productivity. A novel Maximum Production Tracking (MPT) algorithm is introduced to automatically determine the marginal temperature below the DP for maximum productivity. The proposed system is simulated using MATLAB/SIMULINK under different ambient conditions. The obtained results affirmed the potential and verification of the proposed approach.
... 10 In this regard, researchers introduced the atmospheric water harvesting techniques. Some of those techniques include fog harvesting, [11][12][13] dew water harvesting, 10,14 bioinspired water harvesting, [15][16][17][18] vapor compression cycle, 19,20 heating, ventilation, and air-conditioning, [21][22][23] evaporator coils, 24 hybrid air-conditioning/humidificationdehumidification system, [25][26][27] thermoelectric cooling, [28][29][30][31][32] radiative cooling condenser, 33,34 selective membrane, 35,36 and adsorption based water harvesting. [37][38][39][40][41][42] Among all these technologies, adsorption-based atmospheric water harvesting (AWH) technology has gained attention in recent years because of its ability to extract the enough amount of freshwater using minimum amount of energy. ...
Thermally driven adsorption-based atmospheric water harvesting (AWH) is becoming an emerging technology to provide potable water. In this regard, various adsorbent materials including solid (MOFs, silica-gels, and zeolites), liquid (CaCl 2 and LiCl), and composite adsorbents are explored in the literature. This study reviews recent advancements in adsorbent materials based on their water production capacity at different conditions that is air temperature and relative humidity (RH). The MOF of type MIL-101(Cr) shows water production capacity of 3.10 L/m 2 /day at RH ranging from 10% to 40%. Similarly, Zr-MOF-808 possesses water production capacity of 8.60 L/m 2 /day at RH more than 50%. Among the studied silica-gels, mesoporous silica-gel shows highest water production capacity that is 1.30 L/m 2 /day at RH ranging from 10% to 40%. The zeolite yielded water production capacity of 0.94 L/m 2 /day at RH ranging from 10% to 40%. On the other hand, liquid adsorbents like CaCl 2 + cloth, K-LiCl showed water production capacity of 3.02 L/m 2 /day, and 2.9 g/g/day, respectively at RH of about 70%. Composite adsorbent modified with binary salts and functionalized carbon nanotubes resulted water production capacity of 5.60 g/g at RH of about 35%. The study will be useful to identify the energy-efficient adsorbent for the development of sustainable AWH device.
... According to this design, 240 ml of drinking water has been produced in 10 h with a relative humidity of 90% and a mass flow of 25 g/s [4]. Two thermoelectric coolers have been used to construct and test a portable drinking water generator weighing 7 kg, and the FIGURE 1 Schematic of water production cycle from air [6] influence of relative humidity and airflow has been looked at the input of the panel. The amount of water produced depends on the relative humidity density and airflow, and the maximum amount of water production is 25.1 g/h and electricity is 58.2 W [5]. ...
... Also, if the system is turned on and off automatically, no optimal electric current will be generated. According to the design of this system, with a relative humidity of 75% and a temperature of 318 K, and with the help of 20 W of electricity to start the system, 25 ml of drinking water is produced in 1 h [6]. The exhaust air of the sample systems is saturated at any temperature and humidity [6], but due to the exact design, it has been determined that saturation occurs when the relative humidity area is more than 90% [7]. ...
... According to the design of this system, with a relative humidity of 75% and a temperature of 318 K, and with the help of 20 W of electricity to start the system, 25 ml of drinking water is produced in 1 h [6]. The exhaust air of the sample systems is saturated at any temperature and humidity [6], but due to the exact design, it has been determined that saturation occurs when the relative humidity area is more than 90% [7]. The home model of the presented model produces 22-26 L of drinking water daily and its energy consumption is 220-300 W/h [7]. ...
Today, many countries are facing water shortage due to population increase as well as groundwater pollution. To overcome this problem, a variety of techniques have been developed and implemented, one of the most recent being the condensation of water from humid air. Aqueous vapour in the Earth's atmosphere includes a significant amount of water that could be used to supply potable water. One of the methods for condensing water vapour in humid air is to use thermoelectric coolers. In this study, production of potable water by thermoelectric coolers, which is one of the optimal methods for trapping moisture in order to produce fresh water by condensation, has been studied. Fundamental concepts in the design of thermoelectric coolers for the production of potable water have been discussed by the thermoelectric element. According to the specification of temperature, pressure, relative humidity and desired geographical location variables, the maximum amount of water production can be achieved. Modelling results demonstrate higher water production with the thermoelectric method for Ramsar (318 L) in comparison to Bandar‐Abbas. Similarly, for this geographical point, the proposed hybrid solar panels efficiency results in 62.67% by mid‐December with 49.33% on thermal efficiency and 13.33% on electrical efficiency.
... TER module used in Medical kit as non-toxic refrigeration box [20]. TEC used for water harvesting from humid air [21]. Artificial nanostructures of Holey Silicon increased the cooling effectiveness of bulk silicon, and its thermal conductivity is favorable for thermal management in advanced electronics [22]. ...
A thermoelectric air-cooling system (TEACS) is an innovative technology based on the thermoelectric cooling phenomenon. The absence of heavy moving parts to obtain a cooling effect reduces intense vibrations than the traditional cooling system. Moreover, this system is eco-friendly as harmful coolants are not used or produce any harmful elements such as CFCs. The thermoelectric module works on direct current (DC), heating & cooling phenomena depending upon the direction of current flow. Peltier modules are made up of two unique semiconductor materials, such as Bismuth Telluride (Bi2Te3) in the form of pillars sandwiched between a pair of ceramic plates. This paper covers the design and fabrication of an automated thermoelectric air-cooling system. The Peltier module is sandwiched between two Aluminum heatsinks on each side of the Peltier module. Arduino microcontroller is used to provide automatic temperature control. Air is passed through the cold side, and water is used to reduce the heat on the hot side. This system reached 25°C within 300 seconds and 700 seconds to reach 15°C from 30°C ambient room temperature. The novelty of this TEACS has a COP of 1.13 achieved by careful adjustment of electrical parameters with a cooling capacity of 648 W, and the designs are fabricated by using eco-friendly materials.
