Comparative meta-analysis of desalination and atmospheric water harvesting technologies based on the minimum energy of separation

Temporal and spatial variability of energy intensity for atmospheric water generators

“…As air passes over the cool side, the air is lowered below its dewpoint resulting in condensation of water vapor [15]. The advantage of thermoelectric cooling is that it does not require a compressor or refrigerants, but these systems are significantly less energy efficient than vapor compression cycle systems [16].…”

“…Systems based on refrigeration and the vapor compression cycle have the highest yield in locations with hot and humid environments [17][18][19]. Studies have found that refrigeration based AWG devices exhibit an 'exponential-like' increase in energy requirement as RH approaches zero, and energy requirements are four times lower when RH is greater than 75% compared to when it is less than 40% [16]. However, regardless of environmental conditions, energy consumption is greater than conventional desalination methods, leading AWG technology to lack commercial competitiveness when a source of brackish or seawater is available [17].…”

“…The main types of sorbents consist of classic adsorbents, metal organic framework, biomimetic materials, silica gels, and hygroscopic salts and composite adsorbents [7,13,20]. Based on currently available materials, sorption devices produce low yields in comparison to refrigeration vapor compression cycle systems making them less economic due to the requirement for large scale implementation for a sorption device to produce enough water to meet typical demands [6,16,17].…”

Experimental Analysis of Atmospheric Water Harvester Using Ammonia Vapour Absorption System

“…Various methods were used for harvesting water from atmosphere, including vapour compression refrigeration, thermoelectric, sorption, adsorption and desorption, ultrafiltration and expansion techniques. The machines available on the market use the vapour compression condensation (VCC), the (VCC) is characterized by high energy performance, its specific energy consumption (SEC) is about 220-300 Wh/kg, while 22-26 L/day can be produced [7]. The technology used in the AWH machines produces water with 0.03 JD/L cost, which is considered higher than tap (0.001JD/L) or bottle water (0.025JD/L).…”

“…The technology used in the AWH machines produces water with 0.03 JD/L cost, which is considered higher than tap (0.001JD/L) or bottle water (0.025JD/L). If AWH machine is to be competitive, then the produced water price must be reduced by reducing energy consumed per litre, energy cost, maximising water harvested or if water is to be transported long distances, where its cost may rise to 0.7 $/L [7,8]. In order to maximise the harvested water amount, thus reducing SEC, research on enhancing heat transfer including fin natural/forced convection [9,10] or different technique must be used.…”