[HN Gopher] Seawater Greenhouse (2017)
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Seawater Greenhouse (2017)
Author : zeristor
Score : 64 points
Date : 2021-03-09 08:55 UTC (1 days ago)
(HTM) web link (seawatergreenhouse.com)
(TXT) w3m dump (seawatergreenhouse.com)
| zeristor wrote:
| Brine utilisation for cooling and salt production in wind-driven
| seawater greenhouses: Design and modelling
|
| Abstract:
|
| Brine disposal is a major challenge facing the desalination
| industry. Discharged brines pollute the oceans and aquifers. Here
| is it proposed to reduce the volume of brines by means of
| evaporative coolers in seawater greenhouses, thus enabling the
| cultivation of high-value crops and production of sea salt.
| Unlike in typical greenhouses, only natural wind is used for
| ventilation, without electric fans. We present a model to predict
| the water evaporation, salt production, internal temperature and
| humidity according to ambient conditions.Predictions are
| presented for three case studies: (a) the Horn of Africa
| (Berbera) where a seawater desalination plant will be coupled to
| salt production; (b) Iran (Ahwaz) for management of hypersaline
| water from the Gotvand dam; (c) Gujarat (Ahmedabad) where natural
| seawater is fed to the cooling process, enhancing salt production
| in solar salt works. Water evaporation per face area of
| evaporator pad is predicted in the range 33 to 83 m3/m2*yr, and
| salt production up to 5.8 tonnes/m2*yr. Temperature is lowest
| close to the evaporator pad,increasing downwind, such that the
| cooling effect mostly dissipates within 15 m of the cooling pad.
| Depending on location, peak temperatures reduce by 8-16 degC at
| the hottest time of year.
|
| https://publications.aston.ac.uk/id/eprint/31704/1/Brine_uti...
|
| [Edited for link to pdf paper, and abstract]
| davidhunter wrote:
| Sundrop Farms [1] built a 40Ha seawater greenhouse facility in
| Australia with investment from KKR. They managed to get multi-
| year fixed pricing due to the undersupply of quality tomatoes in
| the region. This is pretty much unheard of in the industry. The
| facility was sold in 2019 [2]. The original inventor is a fellow
| British fellow, Charlie Paton [3] - he's a great guy and helped
| us get to know the greenhouse industry when we were starting out.
|
| A lot more high-tech greenhouses need to be built. They are a
| great solution for supplying high-quality, locally-grown food,
| with minimal pesticides and resilience to extreme weather caused
| by climate change. They have the same benefits as vertical farms
| but with higher efficiency - especially for crops like tomatoes
| and berries.
|
| Shameless plug: At Optimal, we are solving the barriers to scale
| for high-tech greenhouses. Our team has deep expertise in
| greenhouse horticulture and machine-
| learning/optimisation/control/software.
|
| Find out more about what we're doing here: youtu.be/LDJ_QdUaap4
|
| Team: https://www.linkedin.com/company/optimal-labs/
|
| Contact me (founder) directly if you want to know anything about
| this fascinating way of growing: david@optimal.ag
|
| [1]: https://www.sundropfarms.com [2]:
| https://www.freshplaza.com/article/9104623/new-owners-for-su...
| [3]: https://seawatergreenhouse.com/team
| cmrdporcupine wrote:
| Hey there, FYI on your careers page the "Overseas applicants"
| button just opens the same page in a new tab.
| davidhunter wrote:
| Sorry about that. We're using AngelList as our careers page
| and it's clunky. We're about to change it. In the meantime
| please reach out to me directly on david@optimal.ag.
| ourlordcaffeine wrote:
| I'm surprised they aren't growing hydroponically in such a water-
| constrained environment, as the water use is lower. I guess it is
| due to the difficulty in getting the nutrients to somaliland?
| michaelscott wrote:
| I love the low-tech solution to the problem! Not much more to
| say, I just think it's a great a solution that will go a long way
| to both helping the people in this area of Somaliland, and
| serving as a template for similar projects in other regions of
| the world.
| wolfram74 wrote:
| I'm curious what the life expectancy of the cardboard
| evaporators are, I'd have guessed they would either mold over
| or just fall apart from being soggy all the time. Color me
| surprised.
| black6 wrote:
| In the several years I worked on a non-climate controlled
| manufacturing floor, we never replaced the cardboard in our
| evaporative coolers[0]. We added a quaternary amine-based
| cleaning agent every so often to knock out the mold.
|
| 0: https://www.mcmaster.com/2073K37/
| JoeAltmaier wrote:
| I'm curious how quickly lime etc will clog the cardboard.
|
| I have an evaporative humidifier, and it has a similar
| filter. Every couple of months I throw it away and put in a
| new one, because its turned into a solid block of lime.
| Robotbeat wrote:
| Concentrations of salt of 3.5 percent or higher tend to kill
| mold. So that should help significantly.
| aaron695 wrote:
| Here it is on Google Maps-
|
| https://www.google.com/maps/place/Berbera,+Somalia/@10.40436...
|
| If you are feeling cynical you can pull it up on Google Earth and
| flick through time.
| hyper_dynamics wrote:
| That is so sad to see. It reminded me of this one wood that was
| planted in then desert. You could see it dried out and then
| later cut down.
| Robotbeat wrote:
| Somaliland is now effectively a nation in its own right and
| over the last couple decades has been generally more peaceful
| than Somalia, although international recognition is lagging.
| youngtaff wrote:
| There are others using solar desalination e.g.
| https://www.researchgate.net/figure/The-seawater-greenhouse-...
|
| Think there are some in Morocco and Tunisia too
| riffraff wrote:
| so, how does this look 4 years later?
| Torkel wrote:
| I recommend listening to this podcast, it seems might not be
| totally dead there after all. Podcast was released yesterday
| and they talk about rebuilding it:
| https://www.bbc.co.uk/programmes/w3cszv2l
| hyper_dynamics wrote:
| Dead. There is a comment further down, where you can see the
| state of it in Google Maps.
| zeristor wrote:
| As talked about in this podcast:
|
| https://www.bbc.co.uk/programmes/w3cszv2l
| Torkel wrote:
| Thanks for posting the link to this podcast! I enjoyed
| listening to it. It seems the situation is not as bad as Google
| Earth would have you believe - stuff got torn down in a storm
| but they are planning to rebuild it.
|
| One thing that caught my ears was the short snippet when they
| talk about about how the men in the region are looking down
| upon farming... smells sort of like a "startup opportunity" to
| me.
| alexose wrote:
| Other commenters have noted that this project seems to have
| folded years ago. It thus completes the circle of tech-forward ag
| projects: A huge upfront investment, followed by a press blitz,
| followed by a runway of varying length that leads to the ultimate
| scrapping of the project for parts.
|
| It's really attractive to think we're just a vertical farm or a
| novel greenhouse away from an agricultural revolution. But as
| much fun as is to grow things where they don't normally grow, one
| isn't competing against an empty patch of sand. The competition
| is the entire global food supply, complete with its brutally
| efficient transportation networks.
|
| (The usual rebuttal is that these sorts of systems are only for
| leafy greens and vegetables. Which are nice to have, but not
| really key to sustaining a population. I've noticed that a lot of
| Youtube gardeners do this handwaving as well. It's like, "I feed
| my family of four from my 1 acre farm!" Neglecting to mention
| that they only grow zucchini and 95% of their calories come from
| the grocery store.)
|
| Sorry to sound salty (heh) about this, but the Hard Problems of
| agriculture are extremely hard. The people who succeed as farmers
| do so in spite of tiny margins and enormous operating costs.
| They're more innovative than most people in the tech world.
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