It’s not the heat, it’s the humidity for an energy-saving way to collect water from air

The apparatus being developed is capable of collecting water at night and expelling water during the day when the sun rises and the temperature increases. Courtesy Petroleum Institute

Temperatures this past summer reached as high as 45°C, if my car thermostat can be relied upon. While the arrival of much gentler weather is happiness to some, it is actually a slight disappointment to our team of researchers at the Petroleum Institute in Abu Dhabi. We need all the humidity we can get in our effort to come up with an energy-saving, electricity-free way to collect water from the air around us.

Humidity is nothing but the presence of water vapour in the atmosphere. It is sometimes uncomfortable if humidity levels are high. Water vapour comes from a natural process where water evaporates from different bodies of water, including sea, rivers, wells, shallow water and so on. When water evaporates it remains, in vapour phase in the atmosphere and it leads to a formation of clouds in the sky.

We experience and confirm the existence of water vapour in the atmosphere when we enjoy a cold bottle of something refreshing to quench our summer thirst. On the outside surface of this bottle, a good quantity of water condenses from vapour (which is already in the atmosphere) to liquid. The process is also clear to us if we turn on a window air conditioner and observe the quantity of water collecting at the back side of this AC. In both cases, water condenses from the atmosphere because of changes in temperature (from hot to cold) that lead to the change in phase from vapour to liquid. Achieving a lower temperature than the atmosphere requires energy. In the case of a cold bottle, it has to be kept in a refrigerator, which runs on electricity. The same is also true for the ACs, which also run on electricity. In both cases electrical energy must be supplied to condense water.

The fact that you can collect water from air is fascinating. However, if the method implied requires direct electrical energy, then the concept has already been exhausted in the technical and scientific literature. But if we can collect water without direct use of electrical energy, then it is of paramount importance that such direction is to be pursued. “Pursuing” is what we started doing two years ago in the Petroleum Institute.

What we have developed is an apparatus which is constructed from smart materials that have unique attributes. These smart materials have the ability to collect water when the atmospheric temperature is low and it rejects the collected water when the temperature is high. During nighttime, the temperature in Abu Dhabi is low compared to daytime. Hence, the apparatus we are developing is capable of collecting water at night and it expels water during the day when the sun rises and the temperature increases. The collected water is allowed to accumulate in a container and then can be used immediately for agricultural uses and with further treatment can be adapted for human uses.

The advantage of our apparatus is that it can be used in any place as long as there is humidity. It doesn’t require any extensive infrastructure because it works without electrical energy. The apparatus can be fabricated in different sizes from bottle size to car size, depending on the need. We have submitted patent applications for this invention to the World Intellectual Property Organization and United States patent and Trademark office. Currently, we are working feverishly in our laboratories to test the performance of these smart materials and the apparatus. Hopefully, we can bring this invention closer to reality in the near future.

The higher the humidity the more water we can collect. When you enjoy the next cool bottle, remember that the condensed water on it is as precious to the UAE as an oasis is precious to a nomad in need of shelter, shade and water.

Saeed Alhassan Alkhazraji is an assistant professor and director of the gas research centre at the Petroleum Institute in Abu Dhabi.

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