- Jacob Chambers
- Lafayette, IN
- United States
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Retrofitting greenhouses to make them more viable for desert agricultural production
From his talk I derived that the flexible PV material, that is soon to come out on the market, could be implemented in greenhouse designs possibly with great effect. I am proposing replacing standard glass used for the flexible PV material in a traditional hoop style/ semicircle. The ability to collect the energy from the sun could be used to power LED lighting systems that would provide the spectrum of light necessary to each specific crop. Drawing upon his ambient temperature idea I would like to also postulate that using a system of pipes run underneath the greenhouses would be capable of creating ambient temperatures suitable to crops. In colder deserts would it be possible to tap geo-thermal energy and use the same pipes that cools the greenhouses to also heat them? I viewed an interesting TED talk that discussed greenhouses that captured ocean mists for cooling and water with great effect and believe that their design could be implemented with the PV and ambient temperature designs. Thoughts and comments are greatly appreciate and most important thank you for your time.













Dick Bonnet
The greenhouse I was referring to was Green Circle Growers in Oberlin, OH. They have built a 5 acre range that recycles all their water. They also use robots in their African Violet range. The greenhouse heated by cooling tower water is adjacent to the Homer City Power Plant in Homer City, PA. I don't know the present owner but they have 11 acres, heat with cooling tower water at 95 degrees and give the water back at 90 degrees. I think they paid $10K for the power to run the pumps. The biggest problem at Homer City was the ground heat caused the plants to stretch.
Dick Bonnet
Jacob Chambers
Jacob Chambers
Kurt Foster
Kurt Foster
Jacob, this should give you another potential source of water other than the sea, this invention is not the only possibility, there are other ways to condense atmospheric water. If all of the water used for cooling/heating etc is reused the ongoing need for water should only be for the plants. The Earthship folks also have some great water harvesting / saving ideas, check out their website http://earthship.com/.
Jacob Chambers
As for the lighting issue, I currently attend Purdue University and have witnessed first hand their implementation of LED lighting in agricultural production http://www.agriculture.purdue.edu/agcomm/agnews/public/story.asp?newsid=3033. The idea behind using the flexible PV for covering greenhouses is to cut down on heat transfer into the greenhouses. http://news.cnet.com/8301-17938_105-20078431-1/mit-demos-flexible-solar-panels-printed-on-paper/ . By reducing this heat transfer you would be creating a more ambient temperature while installing the proper infrastructure to control the greenhouse climate.
I really liked the idea of using both warm and cool greenhouses for climate control. What about implementing a control system that could use backdrafts, negative and positive pressures and convection in the pursuit of a stable greenhouse climate? Also I'd like to hear more on using a reservoir or piping for climate control. Robert, I looked into the Biosphere project and it is extremely interesting. They are doing studies a little bit more grandiose in scope than this discussion but I can see the relation quite clearly. I would recommend anyone not familiar with the Arizona Biosphere project look into it. Thanks for the input, keep it coming.
NotReally MyName
Also, since deserts don't have much water in their environments, they endure vast temperature swings between day and night. It'd be a good idea to use the ground (directly) or an underground water reservoir to act as a thermal reservoir to buffer the greenhouse temperatures.
As for LEDs that are tuned to each crop's light spectrum, I don't think that's a great idea. PVs only convert ~50% of the light they receive into electrical energy - and that's for the expensive multi-junction panels. LEDs aren't 100% efficient either, so you're talking about a lot of energy lost before the plants ever have a chance to absorb anything. It'd be more practical to just let nature do what nature does and let the light go directly to the plants.
Toria Hennesey
Robert Winner 50+
All the best. Bob.
Linda Taylor 50+
R H 20+
Kevin Jacobson
Robert Winner 50+
All the best. Bob.
R H 20+