• Irrigation Update

    Sam Griffen • 04/17/2021 at 02:14 • 0 comments

    So I did some testing of the pump. Actually, I did a lot of testing, and there are now drip lines and sprinklers throughout the planter bed. I'm pretty happy with these sprinklers, here is a photo of one:

    With enough pressure, these things spray a lot of water over the garden bed, so that is definitely a win.

    However, there were problems. The pump I had chosen to irrigate the system is small. I chose the pump based on a litres per hour rating, however did not consider the pressure I would need as part of this analysis. Really my only option here was to get another pump, and create more pressure. 

    Did you know that it is actually pretty easy to 3D print a pump as long as you have a motor lying around? I didn't, but found that out pretty quickly. This is my attempt at a pump:

    It works, but really it isn't better than the one I had. A cool experiment regardless, I am sure I can use this for something at some point.

    At about this point, uni started again, and I have not had any time to work on this since. Ah well, there is always the midyear break!

    P.S. I got a big barrel:

    Keep your eyes peeled for the rainwater harvesting system to make this system comnpletely self sufficient!

  • Solar System Installed!

    Sam Griffen • 04/17/2021 at 02:02 • 0 comments

    Okay, this update has been a long time coming. University is insane, and I have been making very very slow progress on this project. So this update is retroactively documenting progress I made over summer, I'll post another update today about some more recent progress.

    Near the end of the summer break, I got hold of a solar panel, battery, and MPPT charge controller to provide energy to the pump, and hopefully a some LED lighting in the greenhouse.

    So, ultimately the goal is to hook my turbine up to power this greenhouse. However, for now a solar panel will do the job. My previous update made some estimates on power requirements, showing that without a heating unit, this thing needs incredibly small amounts of power. As I have decided to whack some LED strip lighting in there when it arrives, I figured I should go well above this power budget. 

    In the end, I got a 10W, 12V panel, and a 12V 6Ah SLA battery. This is 10 times as much generation capacity as I calculated, and almost 70 times more capacity than calculated. Largely, this was because this was effectively the smallest system I could implement without using small components like a mini solar panel, and a LiPo battery or something. At the end of the day, this system needs the capacity to be expanded to far higher power requirements (Heating and lighting, that is going to use a lot).

    Without further rambling, here is a picture of the MPPT charger and the electronics enclosure:

    This unit mounts to the wall of the greenhouse., and has waterproof connectors to interface with the solar panel, and the external electrical equipement (Pump, lights, heating, etc)

    Here is a picture of the solar panel mounted to the fence:

    This thing is rock solid, as it should be given the insane wind we get against that fence.

  • Power System

    Sam Griffen • 10/24/2020 at 04:32 • 0 comments

    First things first, gotta get some power to this greenhouse. A 12V wire from the basement would do the job, however this isn't much fun. A small solar installation is much better, with the goal being to contribute wind power to the system in future.

    Solar Sizing

    Realistically, not a whole lot of system sizing can be completed, as the system load is not incredibly well known at this point. It is likely that the largest load for now will be the pump, however in future I would like to include a fan heater to raise the temperature through the winter and overnight.

    According to the AliExpress listing, the pump will use about 4.8W when in use, and will operate at 240L per hour. According to this handy article, it seems that each square meter of growing area will need about 16L per day at most. Given the glasshouse being sized has about 2 square meters of growing area, the system should be able to pump 32L per day. Given the pump capacity, it is safe to assume that the pump shouldn't be on for more than about quarter of an hour per day. Therefore, the total energy usage per day from this pump will be 0.72Wh.

    When a heater is implemented, it seems reasonable to allow for up to 1000W of heating. As a heater has not been sized, this is just based on some vague research on heating greenhouses. 

    DevicePower Consumption [W]Usage Per Day [h]Energy Per Day [Wh]
    Pump4.8W0.150.72
    Heater1000W33000
    Total Energy Per Day [Wh]:3000.72

    Realistically, the pump doesn't make any difference. Unsurprisingly, whatever heater is utilised will make up the bulk of the energy consumption.

    Using the NIWA SolarView tool, it seems that I can be expecting an average of 2.05 peak sun hours per day during the depths of winter. This means that in order to power the system in an ideal way, a 1.5kW solar panel installation would be required. This is not feasible, nor is it very sensible. As a compromise, the biggest panel I could afford was utilised, and the heating will be scaled down to fit within this power budget.

    Eventually, a wind turbine will be added to generate energy, at which point more heating may be possible. Realistically, wind energy is a better solution for heating a glasshouse anyway. Processing the NIWA SolarView data, the weekly total irradiance follows the expected trend, with less solar available in winter. Heating will be needed most during winter, so solar does not really solve this problem.

    Therefore, the solar installation is primarily intended to have a basic monitoring/watering system installed, with a heating system being designed after a turbine is installed.

    I am still looking for solar panels, and will update this log when I have got some hardware to work with.