Extracting water from atmosphere by using Desiccant Cooling systems, and perform a comparative analysis between different AWG Technologies available.
Atmospheric water generators (AWG) are the machines that can capture water present in the air in the form of moisture. It should be understood that even in the driest of places the humidity level in never zero hence some amount of water is always present in the air. The atmospheric water generators
2025-06-28 16:32:29 - Adil Khan
Extracting water from atmosphere by using Desiccant Cooling systems, and perform a comparative analysis between different AWG Technologies available.
Project Area of Specialization Mechanical EngineeringProject SummaryAtmospheric water generators (AWG) are the machines that can capture water present in the air in the form of moisture. It should be understood that even in the driest of places the humidity level in never zero hence some amount of water is always present in the air. The atmospheric water generators have the ability to tap into that. Harvesting this water by state-of-the-art dewing technology can be extremely energy intensive and impractical, particularly when the relative humidity (RH) is low. In contrast, atmospheric water generators that utilise sorbents enable capture of vapour at low RH conditions and can be driven by the abundant source of solar-thermal energy with higher efficiency. Desiccation based AWG only uses sunlight and air to extract water from atmosphere. So by using desiccation based AWG we can generate gallons of fresh water on a daily basis with minimum energy consumption.
Project ObjectivesWater is the juice of life that is essential for our existence. Fresh water scarcity is growing day by day. We have seen cities like Karachi, Bangalore witnessing acute water shortage over the last decade. For now, water transportation have provided some relief but within a decade it is believed that 50% of the world's population will live in areas without access to clean fresh and safe drinking water. Interestingly many of the water strained areas are coastal this means they have high humidity level for most part of the year. For example, in Karachi the annual average relative humidity remains above 75%. So the main objectives of this project are as follows:
- To give the idea that how we can easily combat with growing water scarcity. And
- How to give access to each and everyone to fresh, clean and drinkable water with minimum cost and minimum Energy Consumption by utilizing Solar Energy and Relative Humidity of air.
The desiccation based AWG system requires a three step process. First air is blown to a container that has silica gel beads, During the night the beads soak up the moisture from the air note that relative humidity is higher at night time during the day time the solar collectors heats up the air this hot air is passed through the water-rich silica gel beads as the beads get hot the release the moisture content which is picked up by the hot air now it is much easier to condense hot air carrying large amount of water compared to air at normal temperature this is because hot humid air can be condensed even at normal ambient temperature as the hot air interacts with membrane at ambient temperature its vapor condenses which is then collected.
Benefits of the ProjectThere are multiple advantage of using atmospheric water generators for example no transportation of water is needed, no plumbing infrastructure is required and even the need of plastic bottles for carrying water is eliminated. And this technology can be shrunk down to a level where it can fit into cars or boats very easily and when linked with solar energy the running costs is very low. While the main advantages of thermal desiccant systems is that instead of converting sun’s energy to electricity it can efficiently use heat produced by the sunlight to achieve the process of extracting water from air only a small amount of electricity is required to run a fan to circulate the air. The second advantage is that the yield for this system is higher because hot air can hold much more water than cold air. So liters of water can be produced daily by just utilizing Solar light and Relative humidity of air.
Technical Details of Final Deliverable- Water-cooling adsorption is applied to maximize the RR. The adsorptive process will be almost isothermal, which is beneficial in enlarging the water uptake.
- Water-cooling condensation is adopted to reduce the SEC. The cold water comes from ground-source heat exchangers, radiative coolers, or cold storage tank (night storage and day discharge).
- The sorber made by a water-sorbing heat exchanger is introduced to internally cool or heat the desiccants, which further decrease the required temperature of the heat source and the outlet air temperature of the desorber.
- Heat recovery is involved between the outlet air of desorber and the outlet air of condenser to reduce the SEC
-
It is estimated that this project can produce upto 10 litres of fresh water daily at less than 5 cents per litre and even cheaper if it’s operated at a large scale utilizing waste heat of industries.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 79900 | |||
| Solar Collectors | Equipment | 2 | 12500 | 25000 |
| Desiccant container | Equipment | 1 | 5000 | 5000 |
| Adsorbant Material | Equipment | 10 | 1000 | 10000 |
| Storage Tank | Equipment | 1 | 5000 | 5000 |
| Air Filter | Equipment | 1 | 4000 | 4000 |
| Water Filter | Equipment | 1 | 8000 | 8000 |
| Fan | Equipment | 2 | 1000 | 2000 |
| Electric Motor | Equipment | 1 | 3000 | 3000 |
| Electric water pump | Equipment | 1 | 3000 | 3000 |
| Main Frame | Equipment | 1 | 5000 | 5000 |
| Solar Collector's Frame | Miscellaneous | 1 | 4000 | 4000 |
| Nut And Bolt Assembly | Miscellaneous | 50 | 20 | 1000 |
| Electric Wires | Miscellaneous | 10 | 40 | 400 |
| Flexible Water Pipe | Miscellaneous | 5 | 100 | 500 |
| 12V Battery | Miscellaneous | 1 | 4000 | 4000 |