The document summarizes the design and testing of a fog harvesting net. It describes how fog harvesting takes inspiration from nature, like how redwood trees and desert beetles collect water from fog. It then details the design process of a prototype net, which used high-density polyethylene (HDPE) and underwent testing. Testing showed that a double-layer HDPE net collected more water than a single layer or nylon net. The document concludes by discussing factors to consider for fog harvesting and recommendations for further optimizing water collection.

1. HARVESTING WATER FROM FOG
MANJUR AKASH 3817569
ADEDOYIN FLOYD OSINLOYE 3823749
JESUS MACHIN RODRIGUEZ 3816523
LSBU

2. Introduction:
• Almost two-thirds of the global population
currently lives under severe water scarcity for
a minimum of one month a year
• Global water demand is increasing yearly by
1%
• Climate change, overpopulation, agriculture
expansion, and economic development
• Air Water Harvesting (AWH)

3. Inspiration from nature
(biomimicry)

4. Redwood Trees
• Fog condenses into the
leaves and body of the
tree and drops off into
the soil
• The total annual water
input that comes from
fog is approximately 34%
• Redwood trees require
600 litres of water daily,
and 40% of their water
input comes from fog
www.livescience.com

5. Namib Desert beetles
& Spider web
Spiders collect water from their
nets
Namib Desert beetles have a
hydrophobic surface at their back
and drink the condensed water
that gets collected on their backs
https://preview.redd
https://upload.wikimedia.org

6. DESIGN PROCESS

7. DESIGN
PROCESS:
Sketch
CAD design
Simulation

8. Design Process:

9. Rig FEA:
FEA simulation was used to determine if
the rig can withstand the wind force:
• Distributed the drag force into four
corners.
• Static stress simulation was used
• No safety factor concerned.

10. Building process: BODY
• PVC pipes with 25mm diameter and 2m length were used
for the physical rig.
• The frame was built by cutting each end of the pipe 45deg
using a hand saw and then connecting them by screwing
thin aluminium L-shaped brackets on each side.
• The net area of the rig was a 1mx1m rectangular frame.

11. L-shaped brackets:
• It was made of a thin aluminium bar cut
into 16cm lengths using a hand saw and
then bent using metal bending tools.
• The team drilled 6mm holes into the
aluminium bars and used 6mm screws to
connect the bar to the pipe.

12. Materials:
HDPE exhibits inherent
hydrophobicity, meaning it has a
natural resistance to water. This
property makes HDPE an excellent
choice for applications where
water repellency is desired
Nylon is a versatile hydrophilic
material, meaning it has an
affinity for water. It exhibits the
ability to absorb and retain
moisture
VS

13. EXPERIMENTAL SET-UP
AND PROCEDURE

14. Experimental set-up:
• Small fan with 1500 to 1800
RPM
• Small spray bottle
• Three pieces of black
cardboard
• A scale
• Cups

15. Experimental procedure:
The fan had two speeds.
For each speed:
300ml of water was sprayed into the net.
The water collected was measured.
The team experimented three times for each net and each speed.

16. Results:
Comparison of Water Collection Levels in
Single Polyethylene Net, Double Polyethylene,
and Nylon Fish Wire net
Comparison of Water Collection Levels in
Single and Double Polyethylene Net using
hydrophobic coating

17. Discussion:
• Fog harvesting nets are a low-cost alternative
technology for collecting water in areas with low
rainfall but high humidity.
• Factors to consider when choosing a material for
fog harvesting nets include mesh size, pore size, and
hydrophobicity.
• High-density polyethylene proved to be the most
efficient material for collecting water from fog
compared to nylon.
• The hydrophobicity of the surface affects the size
and number of water droplets that can be collected.
• Doubling the layers of polyethylene mesh can
increase water collection efficiency.

18. Best location:
• The prototype collected around 33ml of water from 300ml of
fog at a slow wind speed, with potential for collecting
184.8ml in real-world conditions after accounting for a 30%
loss.
• Ideal locations for fog harvesting nets include areas with high
humidity and frequent fog, such as coastal regions or
mountainous areas.
• Proper placement at the right height and angle is important
to maximize water collection.
• The net must withstand various weather conditions, including
strong wind load, heavy rainfall, and extreme temperatures.

19. Things to consider:
• Excessive vibration can decrease the net's
efficiency, but some movement or vibration
may facilitate water droplet condensation.
• Possible challenges with fog harvesting nets
include clogging, damage, contamination of
collected water, and cost-effectiveness
compared to other methods.
• Regular maintenance and inspection are
essential for proper functioning of the fog
harvesting net.

20. Conclusions and
Recommendations for
Further Work:
• The simple net rig is designed for rice
farms or big farms with large fields.
• To collection of more water a bigger
net area can be used.
• The collected water can be used for
drinking or other necessities,
particularly in underdeveloped
countries.

21. Future Work:
Develop a method for purifying the collected water to make it safe for ingestion.
Test it in natural environments to find its efficiency and use different net meshes.
Test another concept of harvesting water
from fog using a ventilation system with
cold water pipes embedded inside.
This system condenses water from fog when air passes through it.
The concept is primarily focused on big cities with tall buildings, such as
London.
The vent system could be integrated into the building's ventilation
system.

22. Video:

23. Thank You For Listening