CCAT greenshed solar lighting

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.

Solar basics

Solar energy can be converted into electricity by photovoltaic panels. This electricity can then be used to power a plethora of devices. Photovoltaics, among other uses, can be used to deliver power to buildings that are not connected to the standard electricity grid. We chose an off grid solar design to exemplify a small scale, self sustainable system which can provide light for various uses in the green shed.

Lighting options

There are many different lighting options that will need to be analyzed. These include a comparison of DC and AC lighting, incandescent, CFL, and LED bulbs. There is a range of criteria that these alternatives will be rated with that includes wattage, lifetime, and cost.

Calculating Battery Size

(insert battery sizing table)

Energy Efficiency

Efficiency will be of great importance to this project for many reasons. These reason include the a reduced total system size, reduced carbon intensity of the system, and decreased system cost. Some efficiency measures such as LED lighting instead of CFL lighting may have a higher upfront cost , but this additional cost should be offset by their lower life cycle energy usage.

Return On Investment

Because the energy generated by this system will offset energy that would otherwise have to be purchased by a grid provider, in this case PG&E, this system will generate revenue in the form of offset electricity cost. This offset electricity cost will help to recover the upfront cost of the system. The value of this energy offset can be calculated and compared to the upfront cost of the system to determine financially feasible project options.

National Electric Code

Although it may not be of importance for this project to meet national electric code, the same standards will be used as a measure of quality assurance. The goal of these standards are to promote safe, reliable, and consistent results from photo-voltaic power systems.

Alternatives

Using the sun’s energy to illuminate the green shed is one of the many options available in terms of renewable energy. Similar projects could be achieved by taking advantage of other available resources such as wind, micro hydro, or geothermal. Wave or tidal energy could potentially be harnessed as well, given that the location was close enough to the ocean. Solar is most preferred in this case because of the availability of donated panels as well as simple installation and maintenance.

Off Grid Power

This photovoltaic system will exemplify the benefits of off grid power. Relief from rising electricity prices will be a benefit. Additionally, trends indicate that the current reliance on petroleum will cause future price increases. Off grid power offers security from these potential downfalls.

Analysis of Solar Insolation

Components of System

P = IV

P: Power in Watts
I: Current in Amps
V: Voltage in volts

Tentative Time Line

Costs

The following table displays the costs for the Green Shed Solar Lighting project. Funding of this project was provided by CCAT. The 100 Watt panels were donated by Scurfield Solar in Arcata, California, which lowered the cost of this project significantly. In addition to the panel, lights were donated from a campus organization.

Installation

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.

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.