WATER HARVESTING FROM ATMOSPHERE

The title sounds nice is it not ?

The English poet Samuel Taylor Coleridge in his poem

The Rime of the Ancient Mariner wrote “Water,water everywhere and not a drop to drink”

This dictum can happen only when you are ship wrecked in the middle of ocean or perched on rooftop helplessly when flood water gushing all around. But beyond this water is available as ground water which can be tapped comfortably. This water is very pure because it percolates through several layers of soil. There is another very good source of pure water

WATER IN THE ATMOSPHERE

Here I am going to present the work of our grandson

Anirudh Subramanian when he was a fifth-grade student at the Forest Trail Elementary School, Austin Texas. Anirudh won the FIRST PRIZE at the Austin Regional Science Fair in 2016-2017. Anirudh’s presentation follows.

Introduction

Good lord, it sure is hot here in the Congo, but there is no water to drink. Not good. The air around you is filled with water vapor. But with no way to turn it to liquid, it is as useful as a car that doesn’t move. But what if there was a way to cool the water vapor into liquid water so you won’t die of heatstroke. In my experiment, I intend to find out just that.

Problem

Can we condense water vapor into water without using external power input? If we can, does the width and length of condensation tube affect how much water is produced?

Hypothesis

I think we can produce water from water vapor without external power input. I think that the wider the tube, more the water produced and the longer the tube, more the water produced.

Abstract

Water is vital to sustaining life on earth. Water is in the air nearly everywhere on earth, even in the most parched desert. But that doesn’t help much when you’re thirsty because most of that H20 is in its vaporized form, not its handy liquid state. All air contains at least a little water. On hot, muggy days, the air feels thick and uncomfortable because it's saturated with moisture. Water generators, harvest the moisture suspended in humid air. The most common method employs technology similar to another appliance in our home, the air conditioner. Warm air passes over a set of coils that are chilled using refrigerant. Because cool air can't hold as much water vapor as warm air, the cold air leaves behind condensation. These solutions use a great deal of energy, usually in the form of diesel-powered compressors. They are also difficult to move, require high technical skills to operate, and expensive to operate and maintain.

In this experiment I am going to find out if there is a way to generate water without using an external energy source. If it is possible, I will find our whether the amount of water produced depends on length and width of the condensation tube.

Background/Research

The water we drink today has likely been around in one form or another since dinosaurs roamed the Earth, hundreds of millions of years ago.

· 1.1 billion people without clean drinking water · 1.8 million people die every year from diarrheal diseases. · 900 children die every day from water borne diseases (WHO 2004) · Daily water use per person: - 350 liters in North America and Japan - 200 liters in Europe - 10-20 liters in sub-Saharan Africa Facts and Figures Facts and Figures

Freshwater makes up a very small fraction of all water on the planet. While nearly 70 percent of the world is covered by water, only 2.5 percent of it is fresh. The rest is saline and ocean-based. Even then, just 1% of our freshwater is easily accessible, with much of it trapped in glaciers and snowfields. Only 0.007 percent of the planet's water is available to fuel and feed its 6.8 billion people.

According to the United Nations, water use has grown at more than twice the rate of population increase in the last century.

1 in 3 people in the world do not have access to clean safe drinking water. Almost all endeavors to generate water from the air around us have required the use of fossil fuels running a generator. But nearly a quarter of humanity still lacks electricity. Even though the use of solar power is on the rise the ideal way to enable water generation is to use wind power.

How is water produced from air?

The principle is based on the water cycle. The air around us has moisture in the form of water vapor. Wind spins a turbine that in turn enables the internal fan blades to spin. This forces air into a condensation tube attached to a metal container buried in the earth. As the warm air meets the sides of the metal container cooled by the soil there is exchange of heat and the water vapor condenses into water and collects in the container.

There are a couple of downsides to this process.

· First, there has to be strong wind to force air through the condensation tube.

· Second, nature loves equilibrium. At some point the soil around the metal container will warm up to the same temperature as the air being forced in and there will be no condensation.

Definitions

Renewable Energy: Energy that comes from resources which are naturally replenished (made again) in a short period of time.

Humidity: The amount of water vapor present in air.

Dew point: Dew point is the temperature at which airborne water vapor will condense to form liquid dew. A higher dew point means there will be more moisture in the air.

Condensation: The conversion of water from the vapor state to a liquid by a reduction in temperature.

Thermal Equilibrium: When two objects at different temperatures are brought into physical contact, heat is transferred between the objects. Once they achieve the same temperature and heat exchange stops. This process is known as reaching thermal equilibrium.

Thermodynamics: Thermodynamics the study of heat and temperature and their relation to energy and work.

Materials

· 9 sheets of Styrofoam

· 18 Styrofoam hemispheres

· 9 Long threaded shaft

· 3 PVC pipe 1½ in wide

· 6 PVC pipe 3 in wide

· 1, 2 and 3 foot long 1-inch-wide copper rod

· 1, 2 and 3 foot long 1.5-inch-wide copper rod

· 1, 2 and 3 foot long 2-inch-wide copper rod

· 9 Metal container

· 9 Plastic tub

· 36 flat Cork piece

· 36 Forks

· Popsicle sticks

· Power drill

· Nuts and end cap

· Freeze wrap

· Glue gun

· Glue stick

· Soil

· PVC cutting pliers

Procedure

Making the vertical turbine

1) Measure a 25 cm diameter circle on the Styrofoam sheet and cut it.

2) Cut the circles in half.

3) Glue 3 popsicle sticks together to make the base and top of the turbine

4) Drill a hole in center and glue the semi-circles on the sticks.

5) Take three Popsicle sticks and glue them end-to-end. They form the support for the 2 semi-circles. Repeat this step another 5 times.

6) Take 1 half of the vertical turbine and slide it up the shaft and put the end cap on top and the nut on the bottom.

7) Glue the supports to the two ends of the vertical turbine.

8) Use a nut to seal the other end of the vertical turbine.

9) Use freezer wrap to wrap the semi-circles for an Air Resistance Barrier (ARB).

10) Repeat this for 8 other vertical turbines

Making the internal air turbine

11) Cut a 2” diameter Styrofoam pad for the rotor.

12) Cut a 1½” piece from a fork handle.

13) Take the cork rectangles and glue them to the fork handles. This makes the fan blade.

14) Glue the fan blade into the rotor. Repeat this 3 more time.

15) Repeat this for 8 more air turbines

Making the Air Chamber

16) Take the Styrofoam hemisphere and drill 5 rows of holes.

17) Take a small piece for PVC pipe and glue it for the vertical turbine to rest.

18) Drill a hole at the top for the vertical turbine shaft to go through.

19) Attach the internal turbine to the shaft.

20) Take the other hemisphere and carve a 2” diameter circle. Put the PVC pipe in the hole and glue it.

21) Stick the 2 hemispheres together and seal the second one with a nut

22) Repeat this for 8 more air domes

Making the water container

23) Drill a 1” hole in the lid of the metal container.

24) Insert the copper rod through the hold and glue it in place.

25) Take a shovel and fill the plastic tub with soil.

26) Put the metal container with copper rod in the tub and cover it with soil.

27) Put the air dome over the copper rod and pile soil around it to hold it in place.

28) Repeat these 8 more times.

29) Wait for 48 hours and excavate the metal container.

30) Pour the water collected, if any, and record the results.

OBSERVATIONS

After 48 hours I observed that the 1ft length tube did not condense any water while the 2” wide 3ft length had condensed the most water. The water condensed had some specks of dirt.

CONCLUSIONS

For the same width of the condensation tube, the longer the tube more the water generated.

For the same length of the condensation tube the wider tube generated more water.

While this proved both my hypotheses were correct the change in width of the tube did not produce as much water as the change in length.

In my experiment I found that water was generated and this design shows promise. But the amount generated is not enough to sustain a family. This could be because of the depth of the condensation chamber. As an extension of the experiment, I would like to see what effects the height of the vertical turbine, size of the internal fan blades and depth of the condensation chamber have on the amount of water produced.

REFERENCES

1) http://iridl.ldeo.columbia.edu/watergen.html

2) http://www2.lbl.gov/Publications/YOS/Jun/index.html

3) https://www.unesco-ihe.org/sites/default/files/wwdr_2015.pdf

4) http://home.howstuffworks.com/atmospheric-water-generators.htm

5) http://ngm.nationalgeographic.com/2010/04/water-is-life

ACKNOWLEDGEMENTS

I would like to thank my mother for guiding me while I entered the observations and created the graph in Excel and patiently sitting beside me, helping me with PowerPoint while I created the flowchart and diagrams and when I typed the project, my father for guiding me with the power tools, and taking pictures and my sister for her encouragement.