RAD Sustainability

Written by Cecelia Verde with research done by Sarah Scott

Next week we are headed over to Cedar Creek Corrections Center to pick up tilapia that they have been growing in their aquaponics system. The prison has a large and successful system that is fully maintained by inmates. We will be fortunate enough to tour the facility, get some tips and see how an efficient aquaponics system operates.

We are particularly excited to be getting tilapia and thoroughly believe they are the right fish for our greenhouse. Tilapias are naturally rugged fish; resistant to disease and parasites, temperature changes, high levels of ammonia and low levels of oxygen.

In an aquaponics system all of these needs should generally be met with little effort. Although fish naturally produce ammonia through their waste, bacteria and the growing plants convert and absorb it respectively. Oxygen is provided during the water’s circulation between the tank and bed. On the off chance that something does come up, tilapia’s strength will give us ample time to address the situation without putting their lives in danger.

We are planning on eating the tilapia! These fish are also super cool because their meat is naturally bland. This gives the caretaker the freedom to adjust the flavor via the fish’s diet and water quality. Giving tilapia a variety of food and potable water adds to their flavor complexity and makes for a tastier fish. We plan on giving the tilapia a high quality food designed especially for them and duck weed. We are adjusting the water quality by making sure what we are adding to the tank is dechlorinated (which involves letting the water sit out for about 12 hours) and something we would all be willing to drink.

In order to eat the tilapia we have to make sure we have enough to keep the system running. This will be done through strategic breeding in separate tanks. Tilapia can spawn every 4-6 weeks and fry, like adults, are relatively easy to care for. The fry will mature quickly and will be ready to eat in only 7 months! Once we have replacement fish we will be able to eat the present adults.

Please feel free to come into the Mod Shop, ask for a tour and meet our new fish!

For more info on tilapia farming check this out:

https://lakewaytilapia.com/How_To_Raise_Tilapia.php

For more info on Cedar Creek Corrections Center:

http://www.doc.wa.gov/corrections/incarceration/prisons/cccc.htm

By Joe Clevenger and Rhianna Hruska, RAD Sustainability.

If you’re a student at The Evergreen State College and have an interest in sustainability, you could possibly start an internship with the sustainability crew at RAD Services. You can gain some college credit and these internships are a great way to get out into the field and do independent work on hands on projects. Some of the fields that we’re exploring are mycology, aquaponics, community gardening, renewable heat and electricity sources e.g. solar and compost heating, data collection, and general sustainability studies.

In the past we’ve had students help us establish and maintain the many gardens on campus, a student focused on solar panels to helped us to analyze data and assess how well our solar panels were producing electricity and heat, and other students helped us to cultivate mushrooms in the sustainability lab in C building. If you would like to do any of these things or you have an idea for a different sort of internship please send us an email at radsustainability@evergreen.edu. In this email let us know who you are, what your sustainability based interests are, and possibly your vision for your internship. We’ll email you back with more information about how to set up an internship and how we think your internship will work. If you email us in fall, you’ll have until the end of week 10 fall quarter to set up an internship for winter quarter and if you email us in winter, you’ll have till week 10 of winter quarter to set up a spring internship. We’re dedicated to working with you to not only further your own sustainability studies, but also to spread the word about sustainability at Evergreen. A key part of sustainability is sharing knowledge, spreading the word about successes and failures, and trying to include many people in the projects that we are working on.

Here is a list of potential projects that students can either volunteer or intern for:

Solar Evergreen:  Photovoltaics and Solar Thermal

• Evaluate existing projects at RAD
  • What is operating, where?
  • How well is it working?
  • Does it need repair or maintenance?
  • Is it saving or producing energy?  How can we tell?  How much?
  • Can it do better?  What would it need?
• Help plan future projects
  • Costantino Recreation Center:  solar thermal to heat pool and/or showers?
  • Recreation Pavilion needs a new roof – can it be solar PV?
  • expand the Library Photovoltaic installation

Forest Garden Specialist

• Reinvigorate the forest garden
  • assess current situation:
    • What is planted?
    • How is it doing?
    • Do we need more light and where?
  • make recommendations:
    • new plantings: what sorts of communities can exist?
    • how do we create potentials for grazing?

• new irrigation system/method
• maintenance system

Mushroom Maintenance

• Assist w developing mushroom path project
• Develop mushroom production on campus
  • find indoor space
    • must be well ventilated
  • choose multiple varieties/methods of growing

Garden Maintenance

• Weeding
• Soil/Plant health
• Integrated Pest Management (IPM)
• Harvest/Plant
• Water/irrigation
• Research opportunities
  • Integrated Pest Management
  • Nutrient cycling
  • Plant Botany
  • Different methods of tilling/planting

Compost Maintenance

• Manage compost heat pile
• Enter and analyse compost heat pile data

Sustainability Photojournalist

• Photographing RAD at work in sustainability
• Photographing other sustainability efforts on campus

• Blog and writing about sustainability

• Submit to the Cooper Point Journal, Green Pages, and other local media
• Could post photographs to the RAD Sustainability Instagram or Twitter

Greenhouse/Aquaponics

• Temp/light intensity data
• Insulative winter nighttime blanket
• Vertical/Horizontal growing
• integrating clams/shrimp
• comparing growth rates in greenhouse to growth rates in adjacent garden
• nutrient cycling
• plant & fish pathology
• botany
• microbial activity

RAD Sustainability Event Coordinator

• Coordinating volunteer days
• Coordinating workshops
• Speakers

10 hours of work/research per week = 4 credits

You can potentially budget 1-2 more shifts than they need each quarter to allow for 1-2 absences throughout the quarter without requiring additional shifts or research.

Credit earning will require faculty coordination

Some folks can do the internships through class just by setting aside hours

Beside the aquaponics greenhouse there is a small shed with a solar tube penetrating the southernmost wall. This solar tube has a dome on the end of the tube outside of the shed. This dome takes in light from all directions and pushes it down the tube. Right below the dome, the inside of the tube is coated with panda film and below the panda film is a six inch aluminum tube. We are collecting data on the light intensity that it being reflected out of the end of the solar tube using a Hobo Pendant that captures light intensity in footcandles. We are also collecting light intensity data outside of the shed just above the solar tube’s dome. Our aim for this solar tube is to find the best way to direct sunlight, so we can give the bottom bed of plants in the aquaponics greenhouse access to more solar radiation. The alternative to this method is buying grow lights and setting them up above the plants. The solar tube method ultimately saves energy as the solar tube requires no energy and just redirects sunlight, but the grow lights require energy to run.

When we first installed the tube, we were getting very low readings for light intensity. We fashioned a twelve inch tube that was coated with panda film. We attached this new tube to the end of the solar tube inside of the shed and, for a while, our readings for light intensity were much greater than without this tube extension. On the 17th of April 2015, our light intensity readings decreased significantly after the twelve inch tube extension was applied. You can see this trend in the graph below. 

This is light and temperature data collected from the end of the solar tube, where we’re hoping to push all the solar radiation.

In this graph, the blue line represent light intensity, which is calculated in footcandles (luminosity / feet^2). The black line is temperature. (Later in this blog post you’ll see we stopped recording temperature for the sake of using less space on our hobomonitor device. ) In an attempt to fix the drop in production and to increase the projected luminosity altogether, on May 6th we fashioned a six inch tube out of aluminum with no panda film lining. We’d learned about the fact that telescope mirrors are made of aluminum, so we wanted to see if it would reflect more solar radiation than the panda film. The graph below shows the light intensity at the end of the solar tube before and after attaching the new aluminum tube extension. 

You can see that on May 6th, our light intensity readings increase drastically. May 6th was the day that we installed the new six inch aluminum extension to the tube, we can see that it seems to have increased our light intensity readings on both the 6th and the 7th. The plants we intend to grow in the bottom part of the greenhouse bed need a luminosity of about 1,000 footcandles, but our solar tube was giving us an average of about two-hundred. We uninstalled the solar tube and replaced it with a professionally made solar tube in hopes of increasing our luminosity readings. After collecting data on this new tube for two weeks, we’re seeing a small increase in luminosity. We’re hitting our mark of 1,000 footcandles, but only on some very sunny days and we only hit this mark for about 10 minutes each of these days. Although showing improvement, these readings are still too low to be usable for a growing space. The below graph shows the data we collected over the past two weeks. 

From this graph you can see that our luminosity spikes at about 1,000, but it only does so for a few minutes at a time. The rest of the time the luminosity readings range between zero and 350.  The grow bed we’re trying to illuminate only has luminosity problems during the spring and summer seasons. During these seasons the sun is much higher than fall and winter and the top bed is shading the entirety of the bottom bed. During the fall and winter seasons, the sun is much lower in the sky and generates a good amount of light in the bottom bed, ranging between about 1,000 to 2,000. Since most of our dips in production are on cloudy days and on really sunny days we’re getting a decent amount of solar radiation, the new solar tube should be able to provide us with the luminosity we need during the summer and spring, but during the winter and fall the sun’s angle will provide the luminosity for us. 

Our next step is to install our solar tube into the side of the greenhouse and then plant some plants and see how well they grow. If these plants grow well, we’ll install a few more solar tubes to illuminate the remaining dark parts of the bed and increase our greenhouse’s food production.

As you may know from our earlier posts, we’re generating electricity for mod 302 using eighteen 275W solar panels. After noticing significant production dips in our solar panels we did some investigation and learned some interesting information about maintaining solar panels, when they’re ideal for electricity generation, and where they stand in regards to other resources. This is the report on these production dips.

Abstract:

The Solar panels on Mod 302 were experiencing dips in production every day from around 10:45am to 11:30am and 12:45pm to 2:00pm. We believe these production dips were being caused by two tall trees to the south of the building. At the before mentioned times, the sun was hiding behind these trees, thus shading the solar panels and reducing their electricity production.

Analysis:

These dips in production were caused by two different trees. One of these trees was almost directly south of the solar panels and the other tree is generally south east of the solar panels. The sun dips behind the southeastern tree at 10:45am and is fully visible again by 11:45am, the sun then dipped behind the southern tree at about 12:45pm and was fully visible again by 2:00pm. In January of 2014 the 302 solar panels showed an average energy production level of 1.28 kWh. During the dips in production we saw power production decrease to as low as .003 kWh (3 Wh) with a high of about .133 kWh (133 Wh). In February, the 302 solar panels showed an average production level of 1.29 kWh. During the dips in February, we saw a low of about .013 kWh (13 Wh) and a high of about .116 kWh (116 Wh). In February the lowest dip is not as drastic as the lowest dip in January, with a small difference of .01 kWh (10 Wh).

Something important to note about this is the fact that the sun’s altitude angle changes drastically as the seasons change. In the winter you may find the sun at an angle of 20 degrees, but during the spring and summer the sun can reach a maximum of 90. So these production dips are only taking affect in the fall and winter, but during the spring and summer the sun rises high above both trees.

Relevance:

With the growing threats that are being caused by climate change, there is an also growing need for renewable resources that emit low amounts of carbon. Solar panels are one of many ways to attempt to satisfy this need for renewables. Solar panels emit significantly less carbon per kWh than electricity pulled from the grid, exactly how much depends on where you are and the systems used to generate grid electricity. When planning urban environments, if you’re going to use solar radiation as a primary resource, you need to design the urban system to have access to this radiation. This may mean slanted roofs facing the incoming solar radiation, placing windows specifically to capture passive solar heat, or removing trees to make way for incoming solar radiation. Planning urban environments, or altering established ones, to be geared towards using solar radiation is known as “solar zoning.” If we want to build communities that are environmentally friendly and sustainable, we need to plan these communities and their locations to have maximum access to the sun’s incoming energy.

I will make another blog post soon explaining how we dealt with this problem.

This is the link to access the data being collected on the PV solar panels on Mod 302:

https://enlighten.enphaseenergy.com/pv/public_systems/ggfa523388?preview=1

TL;DR

Our solar panels were producing little to no electricity at certain times while the sun was out, we realized it was due to two different trees shading them.