Project data
Authors LeifAugustine SughruaIan Norton Arcata, California Deployed 2013 USD 311.2 Photovoltaic system Download Upload your project too!body.poncho-dark-mode .mw-parser-output .mw-ui-button{background:#303134;border-color:#3c4043;color:#bdc1c6}@media screen and (max-width:500px){.mw-parser-output .button .mw-ui-button{display:block;margin:.5em 0}}

CCAT (Campus Center for Appropriate Technology) is a appropriate technology workshop space on the Cal Poly Humboldt campus. CCAT encourages community involvement through campus based projects and the funding of off campus endeavors. The current operating space of CCAT consists of the following permanent structures: a main house for community meetings and living quarters for the rotating co directors, a green house connected in part to the main house, a educational yurt which is currently under construction, and the green shed.

Our project focuses on improving the functionality of the green shed. The green shed currently operates as work shed a space to design, build, and maintain appropriate technology projects. The greenshed is located on the same property as the live-in CCAT center. This close proximity is very convenient, but it is being hindered by a lack of grid connected power. The greenshed can not be wired to the main building because of permitting restrictions and is therefore in need of a lighting system which is off grid and self sustaining.

## Shed background

The CCAT green shed is approximately 18 ft x 10 ft with 180ft2 of floor space, it was constructed several years ago by a group of students in 2009. Since then, several other additions have been implemented by volunteers and students at CCAT; A cob wall (CCAT greenshed cob wall) was put in place on the southern side of the shed, as well as a clay-straw slip wall (CCAT greenshed west wall) which was installed on the West side, the North wall was put in place using the cordwood method (CCAT greenshed cordwood wall), and a rainwater catchment system CCAT greenshed rainwater catchment was added last year. The shed is mainly used for the organization and storage of construction materials that are used on a day to day basis on the CCAT campus.

## Environmental actors

Located in Arcata, California, the site of the green shed has a variable amount of solar irradience, using the PVWATTS v.1 solar irradiance calculator it was determined that Arcata receives a yearly average of 4.48 hours of full sun a day.

## Problem statement

The objective of this project is to design and build a small solar array to light the green shed at CCAT. The greenshed was built in such a way that it would not need lighting during the day, but work is halted as the sun sets. This lighting project will provide enough light for CCAT volunteers to return tools to their proper location and clean up the shed after a day of work. In addition to functionality our system will be used to show how small scale solar can be utilized to solve real world problems. This aligns with the demonstration goals of CCAT.

### Project evaluation criteria

The following criteria will be used to assess the success of this project. These criteria were chosen based on the suggestions of the project coordinator as well as the diligent students who are working on the lighting system. The scale (1-10) represents the importance level of meeting the constraint of each listed criteria.

Criteria Constraints Weight (1-10)
Maintainability Must be easy to clean and maintain the solar array. No more than 2 hours maintenance per month. 6
Aesthetics Must be pleasing to the eye and look professional. 8
Educational Aspect Must include an educational piece for community. 4
Safety & Placement Must be safe for use by CCAT staff and volunteers, must not interfere with work being done. 10
Reproducibility The structure could be reproduced by local builders. 5
Usability Must sufficiently light tool shed. 9

### Installation

Preparing to mount the panel

The installation of this system began with mounting the 100W panel on the roof of the greenshed. We chose an area on the roof that would get the most sunlight, and attached the panel with clamps and aluminum framing. We tilted the panel approximately 45 degrees due south, because the roof of the greenshed faces East and would not receive much sunlight otherwise. We then selected a small area of the roof just below the solar panel where we drilled a hole to allow the wiring to pass into the main building. We used conduit to protect the wiring from damage, and passed it through a rubber "boot" which we then secured into place over the previously drilled hole in order to protect the greenshed from leaking during the winter months. After we had selected our battery, we placed it inside a small plastic storage bin, and cut holes in the side of the bin to allow the wiring to pass in and out of it. The wires running out of the battery were then ran along the ceiling to their desired location, at which point the lights themselves were attached.

## Conclusion

### Testing results

The location of the greenshed receives about 4.48 hours of full sun per day. During the winter months, this value drops to just over an hour of full sun per day. Because of this, we had the option of using several small solar panels which would be connected to their own individual battery pack and power separate strands of lights. Our second option was to use a larger 100W panel connected to a larger 12 volt 12 amp hour gel cell battery which would power the entire light set up. We chose the second option because the larger panel would generate more electricity than the smaller panels combined and, given the rather small amount of solar insolation, be the best option for providing an ample amount of stored energy in the larger battery. Because of the low number of full sun hours, we had to choose LED lights whose combined power usage was just over several watts. Lights that used more energy would exhaust the battery much more quickly, and we feared that CCAT workers could potentially be left in the dark if we chose this option.

### Discussion

In conclusion, this project was a success. The 100W solar panel provides enough energy for the lights to be used after dark, and illuminate the greenshed when it's dark outside for tool returns etc. Since the greenshed will not need to be lit for extended periods of time, the chosen battery will provide enough power for limited usage.

### Lessons learned

While installing a photovoltaic system can seem difficult at first, it is reasonably straight forward. The task, at first, seemed a bit daunting, but tips from local solar contractors quickly put us on the right track. Also, people and/or business' are often more than wiling to offer time or donate materials for projects. We were constantly met with positive responses when requesting donated materials or help. All we had to do was ask.

### Maintenance and Next steps

The solar system installed in the CCAT green shed will require minimal maintenance over the course of its lifetime. The photovoltaic panel on the roof should be cleaned on a monthly basis to ensure that the solar energy falling on it is not being blocked by dust or other debris. Should a problem with the lighting arise, the wiring can easily be checked via an access box on the underside of the solar panel. The battery for this system is located inside the greenshed, and has been placed in a plastic storage box to prevent foreign objects coming in contact with the battery terminals. This box is easily accessible, and can be opened in order to check on the wiring within. If any of the actual lights dim or go out completely, they can easily be removed and replaced with another identical light, which are currently at CCAT.

There are several potential future additions which may be of interest to future students. A motion sensor could be installed for convenience, as well as ensuring that the lights turn off by themselves in case they are left on by accident. A USB charger could also be put in place. It would draw power from the battery, and could charge devices such as cell phones, small lights, cameras, etc.

## Video

Here is a video outlining the set up and components of the CCAT green shed PV lighting.

## Update: October 2013

The Solar Panels have been working well without any issue. Due to tree blockage, the sun does not hit the panel until the afternoon each day, however no adjustments have been made to the panel's angle or location.

In interview of one of the CCAT co-directors, Linnea said: "The battery holds about 20 minutes of life." This was a great feat and surpassed their expectations of the project. She went on to say: "It's good for putting away tools at the end of the day. We don't have to be shuffling around for headlamps after the sun sets."

With a life expectancy of 50,000 hours, and an average use of three hours per day, the installed LEDs are expected to last two years in total before having to be replaced.

Not much maintenance is expected to be required in the next few years of operation. The small amount of maintenance required will be a regular cleaning of the cell cover, which includes clearing leaves and wiping dust that may have collected on the glass. With this maintenance, the cell should last around 40 years before a replacement will be required, according to www.ga4.org. Future plans, as stated under Maintenance and Next steps above, may require the installation of additional solar cells and/or a bigger battery in order to ensure a sufficient energy supply.

## Related projects

Page data
Part of Engr305 Appropriate Technology, CCAT green shed Project ccat, greenshed, photovoltaic, solar, solar panel, lightning system, battery, light bulb, ccat active project SDG07 Affordable and clean energy Augustine Sughrua, Ian Norton, Leif, Gladys Arechiga, Anthony Gordon 2013 CC-BY-SA-3.0 Campus Center for Appropriate Technology (CCAT), Cal Poly Humboldt (HSU), Engr305 Appropriate Technology CCAT greenshed solar lighting/Operations and maintenance manual English (en) 297 Augustine Sughrua, Ian Norton, Leif, Gladys Arechiga, Anthony Gordon (2013). "CCAT greenshed solar lighting". Appropedia. Retrieved August 18, 2022.
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