ElectrOasis integrates technologies for the growing of food, the collection of water and the creation of electrical power for lighting and Internet connectivity. In 2015 Scientific American has identified energy, food, and water as the worlds most critical resources. As such, ElectrOasis combines concentrated solar for energy generation, aquaponic fish farming symbiotically intertwined with the production of organic vegetables as well as water collection and green waste management. ElectrOasis conflates available technologies into integrated artificial and natural ecosystems that are scalable, sustainable, and designed for desert or urban landscapes in arid or wet regions of our planet.
ElectrOasis will harvest sunlight and available discarded natural resources such as paper and green waste to create energy, food, communications hubs, and places for researchers and scholars to connect to the web. An oasis is a special place in the desert where life giving water and shade can be found, though it is also a fertile patch in a desert occurring where the water table approaches or reaches the ground surface. An oasis is also a place of peace, safety, and happiness sometimes in the midst of trouble or difficulty.
This ElectrOasis will provide shade, fresh water, and plant life. ElectrOasis will evolve and extend the oasis notion by constructing a place where water will be collected from moist air and fresh fish will be grown to fertilize edible vegetables. Power generation from daylight solar driving a small turbine will allow internet connectivity and the creation of interior lighting to empower reading, knowledge generation and peace to be found.
It will be a place where information and web connectivity will allow locals and visitors the ability to have connectivity and agency in a world, especially for educational experiences surrounding green technologies.
This ElectrOasis project empowers all to use what is at hand and conflates high technologies and ancient wisdom in new ways. It allows common materials, like pipes, sand, car parts (generators) solar collectors, water, tilapia fish, green waste (paper, vegetable, meat discards, animal waste) in an integrative and systemic way.
These integrated systems can function in deserts where sunlight is plentiful and water is scarce to urban environments. It can also be adapted for any region where people are plentiful with massive needs, though materials and infrastructure are scarce.
Growing Fish: Aquaponics
For over 5000 years the Egyptian’s were known for their aquaponic farming and for thousands of years tilapia were grown in fish farms in the Nile delta.
With ElectrOasis we will re-introduce tilapia farming as a primary source of creating protein for human consumption and for relaxed peaceful viewing.
Nile Tilapia are distinctive with regular, vertical stripes extending as far down the body as the bottom edge of the caudal fin, with variable coloration. Adults reach up to 60 cm (24 in) in length and up to 4.3 kg (9.5 lb.). Tilapia live for up to 9 years and can tolerate brackish water and survive in temperatures between 8 – 42 °C (46 – 108 °F). Tilapias are omnivorous and feed on plankton as well as on higher plants. In recent research done in Kenya, this fish has been shown to feed on mosquito larvae, making it a possible tool in the fight against malaria in Africa, though for this project we are going to create a black soldier fly farm, to automatically feed the tilapia.
In three past projects, I have successfully implemented aquaponics systems in collaboration with Amy Youngs.
Two were indoor systems in urban environments and one was in a desert region of Portugal.
In this installation, the tilapia will reside inside the tank below the dome. The tank will be 300-500 gallons giving the ability to grow 230 Tilapia at one time. 230 tilapia can create quite a bit of fish waste and the great thing is that fish waste makes some of the best fertilizer on the planet when combined with nitrifying and denitrifying bacteria. All the fish waste from this system will be pumped into cleansing beds filled with plants and bacteria and this will serve to cleanse and return the water back to the tilapia tank.
Growing Organic Vegetables: Food
Flow through systems will be implemented around the periphery of the dome on the interior, to maximize available fish and bacterial nutrients with orienting the grow beds in such a way that pumping water to one height will effectively water all plants.
Plants will be chosen to provide maximum growth given the sun cycles and primary crops of the region. Areas for shade and areas for more sun will be implemented using screening materials on the interior of the dome.
Microprocessors will be used to monitor water/soil PH and allow varying amounts of fertilizing inputs or not, given the plant’s needs.
Typical recipes rely on the herbs; parsley, cilantro, mint, basil, rosemary, oregano, bay leaves and thyme and spices like garlic, anise, saffron, cinnamon, caraway, coriander, cumin, fennel, fenugreek, ginger, white pepper, black pepper, red pepper, and cloves will be tested in the system. Vegetables such as onions, bell peppers, carrots, chickpeas, tomatoes, capers, celery, turnips, potatoes, chili peppers, cucumbers and eggplants and these will be explored as suitable to the growth beds
The benefit for the human visitors will be the sound of cleansed water trickling, as it reenters the main tank, which will also create a relaxing, focused aspect to experiencing the space.
Growing Power: Energy/Knowledge
Concentrated solar has been an effective method of generating power in desert regions for some time. With the generation of steam to drive turbines this proposed system will allow a low cost/maintenance solution and entrance into power generation without massive cash outlay.
NUR Energy has been working with concentrated solar with their most recent large scale installations in Tunisia as they have developed the world’s first CSP solar export project between North Africa and Europe. It is located in the Sahara desert and has a solar radiation level of 2500 kWh/m2 annually.
Sill, concentrated solar can be achieved with materials as low tech mylar sheets that are pulled into parabolic solar lens concentrators with vacuums layered into the garbage can tops and then creating a vacuum, to create the parabolic. What is important here, is the knowledge… and ElectrOasis will be the repository for that knowledge, for how to grow food and excel, given the natural resources properly funneled through advanced technologies and methodologies to allow successful implementation of these integrated systems.
For this proposal, we have selected a solar concentrator that will be manufactured out of polished aluminum, for durability.
What is important here is that the solutions and integration of these technologies are scalable. More or less advanced manifestations of the ideas are possible given the desire for a generation of power, a collection of water and growing of food.
What will we do with that solar?
We will use common pipes at the apex of the solar concentrator to create steam. The steam will be used to drive a revolutionary turbine called the TESLA Turbine and that turbine will be attached to a common car alternator to generate power. The pipes that distribute this steam will be common pipes used for cars such as brake lining pipes designed for extreme temperatures and pressures for safety.
Deep cycle marine batteries (power storage) with existing power generators, (car generators) are available in any country of the world and will allow the system to provide light and water pumping during the hours that the sun is not shining.
Where existing solar cell technologies are affordable and available, these methods are also possible; i.e. using solar concentrators also shining on solar cells. High tech and efficient LED technologies will be implemented inside the dome and focused on the seating area, for the creation of light in the evening hours for reading and learning about green technologies.
Part of this project will be to create a web page that will be devoted to green energy solutions in water collection, production of steam, ways of using the steam to generate power, ways of growing food using organic and recycling means such as aquaponics and vermiponics. This can be an ongoing open source project seeking local community input and connecting to world wide web resources. Any desert region or place where there is adequate sunlight can be a possible site for the project with unique flora, fauna and cultural landscape knowledge will be distilled and propagated as to best practices given local environmental factors.
Recycling Waste/Feeding Fish: Vermiponics and Black Soldier Flies
Using controlled methods of introducing green waste, worms would be fed paper and food scraps to allow for the production of soil and plant fertilizers. These systems will be integrated with the river as a model, where water that comes directly from the waste of fish would be pumped into gravity fed systems starting with marsh like conditions where fish solid waste would be denitrified by bacterial cultures, as it progressively flows through cleaner and cleaner containers also feeding organic vegetables.
The fish waste is turned into the best fertilizer the plants would want to consume and in the process sets up a symbiotic space where fish, plants, bacteria, worms, and humans are benefiting from each other.
An additional technology to be implemented will be black soldier fly harvesting zones. These are beneficial as the grubs the black soldier flies birth, are the ideal food for tilapia. Black soldier flies also consume more types of food waste then red wiggler worms.
While the thought of flies may seem gross, they are the ideal solution to not overfishing our oceans (normal food for aquaponic farms) and they don’t carry diseases, they cannot bite or sting and experts report of their voracious appetites eating compost scraps (including pet waste) and eliminating most food scraps in 24 – 36 hours.
They also prevent houseflies and blowflies from laying eggs in the material inhabited by black soldier fly larvae. The amazing thing about the soldier fly larva is that once they are born they have an innate ability to crawl up an incline of 35 degrees and this will be exploited in the design where an incline is created in the waste reprocessing boxes and that waste stream, will have a direct pipe feeding into the tilapia tank. This system empowers biology to do what it does best.
One of the challenges of growing food in a desert is the creation of fertile soil. New land doesn’t have organic matter, so you have to build it up with compost and the worms and soldier flies will be part of that natural process.
Efficient evaporative coolers that are also integrated into the system, will maximize the creation of mini Oases for the worms, the flies, and the fish.
The UNC Institute for the environment http://www.ie.unc.edu/for_students/courses/capstone/13/bsfl_how-to_guide.pdf “Temperature The optimal temperature at which BSFL consume their food is around 95 °F. The minimum temperature for survival is 32 °F for no more than four hours, whereas the maximum temperature is 113 °F. The larvae become inactive at temperatures less than 50 °F and temperatures higher than 113 °F.
The best range of temperature for the larvae to pupate is from 77 to 86 °F. For mating purposes, optimal temperature is around 82 °F (Zhang, 2010).
Diet BSFL can tolerate a widely varied diet. The BSFL feed on many kinds of organic waste such as table scraps, composting feed, and animal manure. They can also survive off of coffee grounds for a few weeks, but coffee grounds are not a sustainable diet. The caffeine from the coffee grounds helps to boost the metabolism and makes the grubs more active. A diet combining kitchen scraps and coffee grounds may help to boost their metabolism.
The BSFL have a limited ability to process any animal products such as meat and fat. Humidity Black soldier fly larvae develop most rapidly at 70 percent humidity.
The rate of weight loss for the BSFL increases with decreasing humidity. The optimal humidity for black soldier fly mating is around 30 to 90 percent.
It is very important to monitor humidity for captive rearing and breeding. We found that it is especially important to keep the grubs’ feeding medium at a proper moisture level—not so dry that it cements the grubs into the feed, and not so wet that they cannot breathe through the pores in their exoskeleton. Additional environmental conditions BSFL do not survive well in direct light or in extremely dry or wet conditions. They prefer to be 8- 9 inches deep in their food source. If they are too far below the surface, they will perform little bioconversion. Female flies avoid any sites that are anaerobic when trying to lay eggs.”
Growing Thirst: Water Collection
Using biomimetic design I have also designed water collecting mesh systems into the dome that allows the collection of water from fog idesertessert. The Carapace and Namib beetles, native to the Namib desert of southern Africa, are known to pull water from the air. We will use multiple layers of stainless steel mesh that rolls around the dome structure in the evenings to collect the moisture in the air common in this region of Tunisia, to collect and funnel that back into the main tilapia fish tank as the curtains will hang above the filtration tanks and fall into the cleansing stream.
The efficacy of the system will depend on the size of the filaments in the nets, the size of the holes between the filaments and the coating applied to the filaments.
Research done at MIT, indicates stainless-steel filaments about three or four times the thickness of a human hair and spaced at twice the distance between fibers is optimal.
Further research indicates a yield of a few liters of drinking water per day, for each square meter of mesh deployed. As curtains on the structure are possible and given the openings in the structure, we would estimate we can collect 6-12 liters of water per evening in this fashion. These screens can be deployed in the evenings for fog collection of water or in the day for more shade when temperatures hit extremes.
We will use inexpensive Arduino Microcontrollers in parallel to monitor many subsystems, such as water pumping with solid state relays, maintenance of interior temperatures with sensors and control of high efficiency LED lighting for evening illumination.
Growing Structures: Architecture
Research into traditional Tunisian architecture is determining the methods of building the structures to house the solar collection systems, the aquaponics, vermiponics and veggie growing beds. Vaulted adobe buildings reinforced with concrete, will create the covered areas for fish and plants with semi shade.
One possible method to build the dome would be to use mounded earth moistened with water, covered with plastic and build the structure on top of the mound. Once the adobe or reinforced concrete is cured the mound is removed, leaving the dome structure shell.
There are many methods of building the structure and another one that could be employed is the earth-bag, where bags function as large coil pots that progressively wind around the structure. http://earthbagbuilding.com/projects/thailand.htm
An additional method that may be explored is the use of plastic bottles in the creation of plastic bottle structures. This method has been successfully used all over the world where building materials are scarce though waste plastic bottles are plentiful. The method is labor intensive and would require many participating in order to allot it to happen.
A rounded seating area will allow locals to sit and watch the fish and monitor the system as well as provide shade and a place for reading at night and connecting to the web for further research and political agency in learning. In parts of the world, where building materials are scarce existing structures can be used to house the aquaponics and plant growing areas. Concrete recycling can also be explored as a means of getting materials that are readily at hand from destroyed buildings.
For this project the team has focused on developing a robust way of power generation with the TESLA Turbine, however the Tesla turbine is not the only way to power this system. Solar cells with solar concentrators would also be suitable. Tesla turbines have been built with high tech laser cutting or as low tech as using recycling metal hard disks from discarded computers.
A team of engineering and art students from the Ohio State University, will work collaboratively with Professor Rinaldo as interns to conceptualize, research and develop a hybridized Tesla turbine with steam recovery. This turbine will be powered by steam generated by linear solar concentrators.
Rinaldo has also invited professor Amy Youngs as collaborator given our past mutual research in aquaponics.
The optimal turbine design lies in the synthesis of efficiency, reliability, and feasibility. The team will perform preliminary design analysis to computationally establish the design based on efficiency. Previous experimental works have determined factors such as distance between the micro-turbine disks, number and diameter of the micro-turbine disks, number of inlet nozzles to the micro-turbine and rotational speed of the rotor effect the efficiency of the turbine . In particular we will be concentrating on measuring the isentropic efficiency. This parameter measures the degree of degradation of energy in a steady-flow device. It involves a comparison between the actual performance of the device and the performance that would be achieved under idealized circumstances for the same inlet and exit states. 
The team aims to explore how these mechanical design considerations can be adapted to ensure long-term reliability while employing readily available cost-efficient materials. This will aid in our goal of constructing the turbine in a manner that caters toward future production. Notice that in one design above we have considered using recycled hard drive platters as in research, we found some prototypes online of others that have produced Tesla turbines using hard drive disk trays. At this, stage we are leaning toward using laser cut aircraft aluminum for reproducibility.
In similar systems, heat transfer fluids such as oils or molten salts are heated in linear troughs. These fluids then boil water that flows in a conventional steam-turbine generators . Our team intends to explore the possibility of a unique modification of this design. First, the water will be directly acted upon by solar concentration allowing for significant design simplification. Additionally, the steam will drive a laminar flow turbine in place of the traditional turbine.
We believe these modifications are a better method of powering a turbine for low-power applications as it has few moving parts. First, it is less costly due to a lower number of required storage and heating tanks. Furthermore, the modifications will allow the team to employ a more elementary energy storage system attuned to low-power applications consisting of a car alternator and deep-cycle car battery.
Power production is the ultimate goal of this project and thus the discovery of the maximum output wattage is critical. For this, turbine testing will follow in the footsteps of the experiments conducted by Vincent Domenic Romanin in his dissertation Theory and Performance of Tesla Turbines (2012) . We will analyze the hybridized system through Computational Fluid Dynamics (CFD).
The team must carefully explore the interface of the turbine and power generation system to properly address and analyze this question. Output power, battery capacity and the power requirement of the electrical consumers must be matched to ensure sufficient current is supplied to the electrical system in all operating conditions and that the battery is always adequately charged . This will be primarily answered during the validation of our design.
Creation of Specifications and Requirements
The ElectrOasis team went through an intense preliminary design phase to bridge the gap from concept to CAD design. The early project configurations were conceptualized and defined as schematics, diagrams, and layouts of the project were completed. Specifications were chosen based on materials that will be robust and readily available to others wishing to replicate this design. Requirements include but are not limited to: cost of purchase and repair of the turbine, size and overall dimensions of the power systems housing, ease of operation and repair of the power systems, and reliability of the turbine.
Creation of Design Concepts
The team has worked over the course of the past two weeks to produce a complete working drawing set of the design concept in SolidWorks. First individual parts were created with careful consideration of future construction difficulty. The parts were toleranced with attention to the particular fit (i.e. clearance fit, transition fit or interference fit). Next the parts were combined into an assembly to gain an idea of how they function together. Examples from the drawing set can be found below in Figure 3.
The team has set up a meeting with mechanical engineering professor Prasad Mokashi to investigate computational fluid dynamic analysis in ANSYS. This simulation software will allow the team to predict, with confidence, the impact of fluid flows on the turbine—throughout design and manufacturing as well as during end use.
Solution Design/Creation of Prototype
This design phase will consist of the fabrication of the turbine. We will make sure to use all the resources available to engineering students. Many of the members of the project team are participants of the Ohio State Formula SAE team with expertise in machining. For advanced fabrication processes, the team will send the parts to the Allfab Incorporated to be machined.
This phase of the design will show the team how the proposed solution will function in “real life” and how it interacts with the real world environmental constraints. It will provide the basis of future testing and will be representative of performance.
Testing/Validation of Design
In the final stage of the process the team will evaluate the performance of the created turbine. We will be able to get an actual power estimate and extrapolate that to predict what the system will be capable of powering once implemented in Tunisia.
Testing will occur in three primary stages. First, we will conduct compressed air tests to calculate torque and RPM values as functions of air pressure. This testing will be independent of the solar concentration and will be indicative of the turbine’s performance. Next, the team will conduct prolonged steam testing to evaluate long-term concerns such as warping in the turbine. Finally, steam testing with alternator and battery will be conducted to ensure system is closed and to gauge the net power output.
The power systems production team is comprised of Professor Ken Rinaldo overseeing Colin Trussa, Anthony Huang and Yizhou Lu. As Mechanical and Aerospace engineering students they/we have access to extensive research databases, laboratory equipment, and modeling software. Our combined skill-sets and backgrounds provide an excellent basis for the mechanical design and implementation of this project and the TESLA Turbine in particular.
Our team consists of three other important members, Associate Professor Amy Youngs (Art: Art & Technology) an expert in aquaponics and vermiponic Gardening and myself (Bio-artist, robotics art) working with Jeremy Viny Art student studying green technologies and Monica Backs Environmental Engineering student, doing research on plants and we are confident in our abilities to see this project through to completion. All these students are returning Fall 2016 to continue on this project.
Additional plant Research:
Olives, grapes, wheat, barley, peppers, dates, peppers, and potatoes are the main produce grown in Northern Tunisia. Since we are trying to grow the plants indoors, with a system that will allow us to keep the soil fairly moist, I believe we will have a wide range of plants to choose from.
Barley is great at preventing soil erosion, suppressing weeds, “scavenging” for excess nutrients and adding organic matter to the soil. Barley is also widely mixed with other crops due to its ability to serve as topsoil and protect the plants with which it grows during periods of drought. Barley doesn’t grow well in soil that is waterlogged, and actually seems to do very well on light, droughty soil with a higher sand and clay content. Its roots can grow to be up to 6.5 feet deep. Barley prefers a soil with a pH range from 6.5-7.5.
- Intercropping barley with increase the amount of N absorbed by barley and returned to the soil in barley residue. Also shows increased amounts of P and K recycling.
- Can grow in drier climates.
- Can protect other plants within the ElectrOasis.
- Establishes deep root systems- do we have the room?
- Usually planted in large quantities/ requires large surface area.
Potatoes grow better in cooler climates and out of direct sunlight. They thrive in well drained, but consistently moist soil. Potatoes plants prefer acidic soil and can be damaged by “Potato Scab” when soil pH is too basic. Maximum growing pH is 6.5, with careful observation to prevent Potato Scab.
- Enjoy constant moisture that could easily be provided within the ElectrOasis.
- Enjoy nitrogen rich soil, and usually not as the expense of the vegetables.
- Relatively short roots (~24 inches)
- Recommended to plant them 1 foot apart.
- Require “hilling” as they mature to prevent sunburn.
- It is advised to practice “crop rotation,” meaning they could not constantly be replanted within the ElectrOasis.
Tomatoes prefer at least 6 hours of sunlight per day as they grow. Well-drained soil is necessary for the success of a tomato plant. Tomatoes prefer loamy soil with a more acidic pH.
- Thrives in acidic soil, similarly to potatoes.
- Healthy plants produce ample vegetation.
- Root systems can be fairly shallow (~18 inches).
- Need to be staked as they grow to support the weight of the plant.
- Require a decent amount of sunlight.
- Too much nitrogen within the soil can cause the plant to grow much larger at the expense of the fruit (large plant with no tomatoes).
Bell peppers prefer neutral soil and full exposure to the sun. They grow best in warm environments (+70 degrees F). These plants prefer moist, but well drained soil.
- Grow best in warm environments.
- Vegetable contains a large Vitamin C content.
- Need to be staked as they grow to support the weight of the plant.
- Require direct exposure to sunlight.
- Too much nitrogen within the soil can cause the plant to grow much larger at the expense of the fruit (large plant with no peppers).
With these 4 plants, the most successful path for water purification would be potatoes à tomatoes à bell peppers.
It is proven that potatoes have a higher yield while rotated with Barley… It is possible that we could make it work? Regardless, it appears that most of the vegetation used within Tunisian cooking requires a lot of attention during their youth.
Spices and Herbs:
- High in Vitamins C and A.
- Prefers soil at a temperature of 70 degrees F or higher.
- Proven to have symbiotic growth with tomatoes. Plant this near tomatoes!
- Loamy soil.
- Requires even watering and often.
- Grow best in rich soil, full of organic matter; this may be an issue for the plants as the ElectrOasis is in its early stages.
- Grows well near tomatoes!
- Aromatic, calming smell.
- Minimal care is usually required.
- Loamy soil.
- Can take over entire garden due to spreading root system.
- Requires even watering.
- Loamy soil.
- Easy to grow; it requires soil above 70 degrees F.
- Grows well near tomatoes!
- Need to be planted about 10 to 12 inches apart.
- Require constant moisture.
- Likes sandy to loamy soil.
- Has a pleasant fragrance.
- Small; it only grows 6-12 inches in height,
- Difficult to grow.
- Requires a lot of pruning and attention.
Typical Recipes rely on:
Herbs: parsley, cilantro, mint, basil, rosemary, oregano, bay leaves and thyme.
Spices: garlic, anise, saffron, cinnamon, caraway, coriander, cumin, fennel, fenugreek, ginger, white pepper, black pepper, red pepper and cloves.
Vegetables: onions, bell peppers, carrots, chickpeas, tomatoes, capers, celery, turnips, potatoes, chili peppers, cucumbers and eggplants.
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