2012-05-19

Semi-hydroponics -- part 2

Hello,

It has often been stated that the research we are doing at EOS (Earth Organization for Sustainability) is such that it simply takes a long time. An important part of the reason for this is that the Life we deal with has it's own slow pace and so when you need to let 4 seasons pass to get the results of a plant development study, there is simply no getting around this.

As you might remember, sometime last year, I mentioned a project of applying technology to horticulture. I put forth the notion that biological organisms preform some functions better than mechanical implements and thus using, say traditional biotechnology, instead of mechanical engineering, may provide better results at raising plants.

It so turns out that while a mycorrizal fungi are indeed very efficient at delivering water to plants and while nitrogen fixing symbionts do indeed provide a very sustainable alternative to feeding plants fossil fuels -- the nitrogen fixing plants are relatively delicate and do not survive the winter unless constantly attended to. As this requirement for constant attendance proved impractical, I am now working at installing formerly frowned-upon mechanical implements, which will enable better resilience of these tiny ecosystems.

The primary problem of the existing system is that the capacity of water that the system is capable of retaining, assuming the characteristics of the soil are fixed at optimum (for the plant), it is dependant on the size of the pot. Pots as you might imagine, are not very big due to practical considerations, and can retain up to 1 litre of water, which is sufficient to retain optimal condition for about 1 day in the summer (due do water loss trough evaporation and photosynthesis). The plan thus would be to install a piping system which will add more water from a larger reservoir as necessary.

I have mentioned that the plant-fungi-symbiont system is powered entirely by solar, so I am implementing this additional system in solar power.

I am proceeding at small incremental steps. I have opted for a design where the solar panels are attached directly to a water pump, to provide more water when it is probably going to be needed and less when unlikely, excess water is then drained from the bottom of the pot and collected back in the reservoir to prevent water and nutrient loss.

The initial step of constructing the drainage system is completed fairly easily (a hole drilled into the bottom of the pot, a tube attached using some adhesive material intended for use in construction and a water tank attached).

The second step, to wire a pump to a solar panel in a functional manner is displayed functioning in the below video:




The single solar panel at 12V, Voc: 22.3V, Vmp: 17.7V, Isc: 280 mA, Imp: 300 mA and 25 € proves to be unable to sustain the current used by the "eco" 8-20V immersive water pump at 230 mA, maximum throughput 500 l/h and an additional 25 € -- and runs at minimal 8V power even in direct sunlight at 3pm, will install a second solar panel wired parallel to improve performance.

I am not sure at this point what to do with the theoretical 500 l/h throughput (this is the weakest pump on the market) as it would be sufficient, if this were physically possible, to water about 12000 pots of plants -- we will see what the practical throughput proves to be.

LP,
Jure