Self-regulating, knitted fabric system development for moisture harvesting
to establish a micro-environment capable of sustaining plant life
Insufficient quantities of affordable irrigation water and hostile dry weather conditions render many areas unsuitable for crop farming. These Drylands, according to the International Union for Conservation of Nature, ‘where the mean annual rainfall … is lower than the total amount of water evaporated … stretch over 41% of Earth’s land surface’ (2010). The increasing global population and the effects of climate change urge the development of untapped assets.
My research focuses on the potential of growing food crops in drylands, utilising knitted textiles as substrate. Industrial knitting is my profession (and my passion) since 1985. The knowledge obtained over the past three decades provides me with a solid foundation for this research. Computer controlled industrial knitting is now capable of creating complex multi-layer-structures from fundamentally different materials. In preliminary knit-tests I was able to develop a mesh structure with basalt-yarn and a glass-yarn. The inorganic compounds of this fabric are intended for the protective outer layer. For sustainability it has to withstand the elements for at least two decades.
The aim is to develop prototype knitted textile system to harvest atmospheric water vapour and create an environment for growing food crops in desert environments. The system is intended to utilise the extreme changes of temperature between day and night for the water-harvesting-process. This ‘poly-tunnel-greenhouse’ would function without any complicated technology and should therefore be inexpensive and comparable low in maintenance.
Water vapour or humidity is always present in the atmosphere. In 2006 Sher patented a method of drawing this water from air by charging a salt. Certain textiles seem to attract moisture as well, making them feeling damp. Furthermore it can be observed that once exposed to sunlight, these damp textiles release a type of ‘steam’. The underlying physics leading to these everyday occurrences will be investigated. To reconstruct, combine and optimise these two processes, a wide variety of yarns is available. Engineered yarns which have been introduced in recent years display properties unthinkable only a few decades ago. By investigating the new developments as well as re-evaluating traditional fibres and materials; would it be possible to create a fabric for harvesting atmospheric moisture?
The relatively small amount of moisture in the atmosphere is unlikely to provide high volumes of water. To maximize the efficiency and to prevent evaporation in piping and storage, it should be advantageous to use this water immediately. Instead of merely ‘producing’ water for irrigation, would it be possible to utilize this water in a more direct way to grow fruits and vegetables?
Harsh weather conditions in the dry lands demand a form of protection to the crops. Excessive exposure to sun and heat will scorch the plants. Strong winds and heavy rain storms can ruin a harvest. Similar to a ‘poly tunnel’ an outer layer could protect the crops. This protective layer could also regulate the air flow to the water harvesting layer and move oxygen-rich air away from the plants foliage.
This research has the potential to provide small hold farmers with life changing equipment. We can create the opportunity to grow food self-sufficiently and generate reliable income.