Testing and Testing Results

Introduction

The Desalination Unit is a device that Gabrielle Goodrow, Erin Krause, I designed to create potable water for coastal Chileans with no ready supply of clean fresh water.  We also designed the Unit specifically so that project was environmentally friendly and self-sustaining.  The Unit uses Solar Humidification to evaporate water, which rids the water of any debris or minerals dissolved in the water, and leaves behind any pathogens in the water.  Gravity then brings the water passed an ultraviolet light, which kills any germs and pathogens that might be in the water, this is a fail safe to ensure that if any pathogens bypassed the evaporation cycle the user would not consume them.  After passing the UV light, the water flows into a separate storage tank where the user can easily access the water.  The Unit receives power from a solar panel with an adjustable mounting.  The solar panel would be mounted somewhere the photovoltaic cells have full access to the sun, and are out of harm’s way, whether on a rooftop or in an open space near the house.  My part of the project, the electrical portion, includes the solar panel, UV light, UV housing, and ensuring that the water is pathogen free.  The electrical portion is there to guarantee that the water people will be drinking is completely free of pathogens.  The electrical portion is also expected run only on green-energy.  The testing procedures used are ways to guarantee that the unit is functioning properly.  My team, Erin Krause and Gabrielle Goodrow, and I worked on the testing.  We also received help from the MCVSD Career Center, Laurie Neyhart, who runs the green house there, and Mrs. Green.

The Testing Procedures

1.      Type: Exploratory/Comparison

Stage: Preliminary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Which green energy source would be most useful and practical for the unit?

Tools and Equipment: Computer with Internet capabilities

Procedure:

1.      Search the internet for information about various types of green energy sources

2.      Compare and contrast different types

3.      Pick an energy source to use

Target: Determine which energy source would be practical for our project.

2.      Type: Exploratory/Comparison

Stage: Secondary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Determine which germicidal UV light we should use for our project, and purchase one.

Tools and Equipment: Computer with Internet capabilities
Procedure:

1.      Search the internet for different types of germicidal UV lights

2.      Compare and contrast different types and prices

3.      Select a germicidal UV light to buy

Target: Choose and secure a germicidal UV light to use for the project.

3.      Type: Exploratory/Comparison

Stage: Secondary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Determine which photovoltaic cells, solar panel brand, size, and watts we should use for our project, and purchase one.

Tools and Equipment: Computer with Internet capabilities
Procedure:

1.      Search the internet for different types of solar panels

2.      Compare and contrast different types and prices

3.      Select a solar panel to buy

Target: Choose and secure a solar panel to use for the project.

4.      Type: Assessment

Stage: Tertiary

State of Solution: During Construction

Conditions: Stationary, Outside, On

Parameter/Specification: Ensure that the solar panels can run the UV light.

Tools and Equipment: eyes

Procedure:

1.      Attach the solar panel to the UV light.

2.      Do not look directly at the bulb, but see that the light functioning.

Target: Ensure that the two items function properly together.

5.      Type: Validation

Stage: Quaternary

State of Solution: Post-construction

Conditions: Stationary, Outside, On

Parameter/Specification: Does any light escape from the UV light housing?

Tools and Equipment: eyes

Procedure:

1.      Turn the light on while the bulb is inside the UV housing.

2.      Diligently look from all angles.

Target: Guarantee that the electrical components of the unit are functioning correctly.

6.      Type: Validation

Stage: Quaternary

State of Solution: Post-construction

Conditions: Stationary, Inside, On

Parameter/Specification: Does the unit purify the water?

Tools and Equipment: Coliform Bacteria Water Test Kit, a sample of the water produced by the Unit

Procedure:

1.      Follow the directions given by the kit.

Target: Guarantee that the water is potable.

The Testing

1.      Type: Exploratory/Comparison

Stage: Preliminary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Which green energy source would be most useful and practical for the unit?

Tools and Equipment: Computer with Internet capabilities

Procedure:

1.      Search the internet for information about various types of green energy sources

2.      Compare and contrast different types

3.      Pick an energy source to use

Target: Determine which energy source would be practical for our project.

Result: After looking into solar, hydro, wind, wave, tidal, and geothermal, I deemed solar power the most effective given the environment of Chile and the Atacama Desert, while being the most practical for the user.

2.      Type: Exploratory/Comparison

Stage: Secondary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Determine which germicidal UV light we should use for our project, and purchase one.

Tools and Equipment: Computer with Internet capabilities, wires, solar panel, watt/volt meter, socket, socket adapter, battery
Procedure:

1.      Search the internet for different types of germicidal UV lights

2.      Compare and contrast different types and prices

3.      Select a germicidal UV light to buy

Target: Choose and secure a germicidal UV light to use for the project.

Result: I decided a Plusrite, screw-in, mercury-arc, 10.5V, 3w germicidal UV light would be best for the project, and purchased one.

3.      Type: Exploratory/Comparison

Stage: Secondary

State of Solution: Preconstruction

Conditions: Preconstruction

Parameter/Specification: Determine which  voltage and wattage solar cells, we should use for our project, and purchase one.

Tools and Equipment: Computer with Internet capabilities
Procedure:

1.      Search the internet for different types of solar panels

2.      Compare and contrast different types and prices

3.      Select a solar panel to buy

Target: Choose and secure a solar panel to use for the project.

Result: I determined that we should use two 6V, 1.5w solar panels and purchased them.

4.      Type: Assessment

Stage: Tertiary

State of Solution: During Construction

Conditions: Stationary, Outside, On

Parameter/Specification: Ensure that the solar panels can run the UV light.

Tools and Equipment: eyes

Procedure:

1.      Attach the solar panel to the UV light.

2.      Do not look directly at the bulb, but see that the light functioning.

Target: Ensure that the two items function properly together.

Result: So far, I have been unable to make the solar panel power the UV light.  I have tried various arrangements, different solar panels, regulators, and resistors, but to no avail.  When a bulb was given too much voltage the was a flash, and the bulb had blew out.  The problem is most likely that the amperage of the solar panels is too low.

5.      Type: Validation

Stage: Quaternary

State of Solution: Post-construction

Conditions: Stationary, Outside, On

Parameter/Specification: Does any light escape from the UV light housing?

Tools and Equipment: eyes

Procedure:

1.      Turn the light on while the bulb is inside the UV housing.

2.      Diligently look from all angles.

Target: Guarantee that the electrical components of the unit are functioning correctly.

Result: Testing has been unable to proceed.

6.      Type: Validation

Stage: Quaternary

State of Solution: Post-construction

Conditions: Stationary, Inside, On

Parameter/Specification: Does the unit purify the water?

Tools and Equipment: Coliform Bacteria Water Test Kit, a sample of the water produced by the Unit

Procedure:

1.      Follow the directions given by the kit.

Target: Guarantee that the water is potable.

Result: We tested two samples of water one of the cleaned water and one of the brine, each 10ml.  The Coliform test confirmed that the processed water was safe to consume. 

Conclusion

            Unfortunately, I have been unable to complete much of my testing.  I have determined that solar power was the best choice.  I am in the process of securing a solar panel and a germicidal ultraviolet light, and I started the testing of the processed water.  Ultimately, I have not finished my testing and I have a great deal of work left to do.

Works Cited

. "DT Series Computer Desks". Smartdesks. N.p., n.d. Web. 29 Feb 2012 <http://www.smartdesks.com/computer-desks-dtseries.asp>.

. Google Maps. N.p., n.d. Web. 29 Feb 2012. <http://maps.google.com/>.

Paige, Sarah. "Understanding Your Computer". TechWench. N.p., 14 Feb 2012. Web. 29 Feb 2012 <http://www.techwench.com/understanding-your-computer/>.

. "Personal computer". Wikipedia. N.p., n.d. Web. 29 Feb 2012 <http://en.wikipedia.org/wiki/Personal_computer

. "UV-C Bulbs; Troubleshooting". American Aquarium Products. N.p., n.d. Web. 29 Feb 2012. <http://www.americanaquariumproducts.com/UVBulbTroubleShooting.html>.

. "Why Buying A Cheaper Computer May Be A False Economy". tech2date. N.p., 04 May 2011. Web. 29 Feb 2012. <http://www.tech2date.com/why-buying-a-cheaper-computer-may-be-a-false-economy.html>.

. "YaMing® Chargeable 9V 3W Crystalline Silicon Solar Power Module Panel". dinodirect. N.p., n.d. Web. 29 Feb 2012. <http://www.dinodirect.com/solar-panel-9v-3w-6v-rechargeable-lithium-battery.html>.

Log 6 - MP3 - 8 March 2012

What we are accomplishing

- Finished and handed in Self and Design Evaluation

 

What Problems we are experiencing

- Trying to find a solution for the UV light issue

What direction we are heading in

- Trying to finish the project

Log 5 - MP3 - 6 March 2012

What we are accomplishing

- I have purchased two 6V solar panels

- Working on Self and Design Evaluation

 

What Problems we are experiencing

- I'm still looking for a viable solution to the DC to Ac problem

What direction we are heading in

- Trying to finish the project

Log 4 - MP3 - 29 February 2012

What we are accomplishing

- Finished the 96 hour testing period at the career center

- We are going to test the samples we gathered from the testing period

What Problems we are experiencing

- I'm having trouble locating a 10.5V solar panel.

What direction we are heading in

- Looking for a solution to the UV problems

- Wrapping up the rest of the project

Germicidal UV Radiation from the Sun and Evaporation

I did some research into how long water has to sit in the sun in order for the sun's germicidal UV radiation to clean it.  To my surprise, water needs only 6 hours in the sun to kill pathogens (2 days if the sky is cloudy).  I do not know how well using the sun would work for this project, because I am unsure as to how far the light would penetrate the water, and due to the shape of the barrel during certain portions of the day sunlight might not reach the water.
I then realized that when water evaporates, the pathogens do not evaporate with the water.  Therefore, the water that flows into the storage tank is already free of pathogens, and the UV light becomes obsolete.  However, the unit will still have UV light to act as a fail safe.

These websites are what led me to these conclusions
http://en.wikipedia.org/wiki/Rainwater_tank
http://en.wikipedia.org/wiki/Solar_water_disinfection

LED germicidal UV Lights

I did some research into LED germicidal UV Lights, because an LED would require much less electricity than a regular germicidal UV light.  Unfortunately, LED germicidal UV Lights are a relatively new technology, are not easily available, this American Air and Water says "However at this time there is no UV LED equipment that can compete with the high output UV lamps in real world production conditions."  LED germicidal UV Lights are therefore, not the best course of action, and I will continue using regular germicidal UV Lights.

Log 3 - MP3 - 14 February 2012

What we are accomplishing

- Constructed email to Atlantic Ultraviolet

 - Researching the possibility that the UV light was DC or AC while the Solar panel was the other

 - Looking for other sources of UV radiation that would come with a fixture (e.g. a nail curer, which runs on batteries and a cord, but unfortunately, is not germicidal), to avoid the problems I am experiencing

What Problems we are experiencing

- I am unable to run the UV light, looking into possible reasons why

- I need a solar panel and a UV light

What direction we are heading in

- Looking for a solution to the UV problems

Log 2 - MP3 - 09 February 2012

What we are accomplishing
- Called 1000bulbs.com, unfortunately, they were unable to answer my questions.
- Received information about Atlantic Ultraviolet, who are more focused on ultraviolet, and can probably better answer my questions.

What Problems we are experiencing
- I am unable to run the UV light, and am unsure why.
- I need a solar panel and a UV light.

What direction we are heading in
- I am trying to finish our construction, and am preparing for testing.

Log 1 - MP3 - 06 February 2012

What we are accomplishing
- We have located a facility that will allow us to test the Unit

What Problems we are experiencing
- Our biggest problem is that we are unable to run the UV light, and we are unsure why.
- Our second problem is that we still don't have a solar panel.

What direction we are heading in
- We are trying to finish up our construction, and we are preparing for our testing.

STEMM Report; Science, Technology, Engineering, Manufacturing, and Math

Emily Hagge

STEMM Report; Science, Technology, Engineering, Manufacturing, and Math

Introduction

The Problem

 Water is a necessity of life; humans can survive a maximum of 5 days without water if they are in good health and have the right circumstances.  In the wrong circumstances, a person dies within an hour.  To sustain life, the first priority is to ensure one has a fresh, clean source of water.  However, people in developed countries have grown take this for granted.  However, not everyone has this luxury.  Citizens of countries where poverty, sanitation, and education are major issues still do not always have a clean fresh water source, and without a better option, draw their water from the first available source.  This can range from a polluted pond to a contaminated well.  The Atacama region in Chile is a dry underdeveloped area where most water sources are either salt or polluted.  The area receives very little rainfall, and the people in the Atacama region are no longer able to depend on their rivers for water because of pollution caused by the mining companies.

The Solution



Fig. 1 The adjustable solar panel mounting



Fig. 2 The separate storage

 tank and the UV housing



Fig. 3 The evaporation chamber

 One  solution is to design and build a small, green-powered desalinization unit that can be constructed with materials and money appropriate for Chile, which would be used by people in the Atacama region with no ready supply of clean fresh water.  The Unit uses Solar Humidification to evaporate water, which rids the water of any debris and minerals dissolved in the water.  Gravity then brings the water past an ultraviolet light, which kills any germs and pathogens that might be in the water, and into a separate storage tank where the user can easily access the water.  The Unit receives power from a solar panel with an adjustable mounting, Fig. 1 shows the mounting designed for the panel.  The solar panel should be mounted somewhere that the photovoltaic cells have full access to the sun, and is out of harm’s way, whether on a rooftop or in an open space near the house.  Fig. 2 and Fig 3 are the UV housing attached to the separate storage tank and the evaporation chamber, respectively.  There is no picture of the solar panel and the mounting because the solar panel has not arrived due to shipping lag, and without the solar panel, I have been unable to construct the mounting.   

The Science, Technology, Engineering, Manufacturing, and Math

Type of System

The Desalination Unit is an innovation; the project uses established principles of solar humidification, solar power, and ultraviolet radiation to create potable water.  The Unit is an open system; the design uses the environment, the sun, gravity, and the climate, to efficiently clean the water.  The Unit is also a technological system, utilizing various technologies to be fulfill the needs of people.

Engineering

            The Unit uses several types of engineering; Electrical, Environmental, and Mechanical.  Electrical engineering, the study and application of electricity, applies to the solar panel, which is the source of the electricity used to power the UV lights.  The Unit uses Environmental engineering, which deals with creating clean water using the UV light.  The adjustable mounting of the Unit uses Mechanical engineering, the application physics and material science to design.

Manufacturing

            Mass-production is the creation of large quantities of homogeneous items.  Mass-produced products are often not customizable, and are generally machine-made.  Fortunately, the electrical portion of the Unit does not require handcrafting or personalization.  Most other methods of manufacturing take a lengthy amount of time for a finished product and leave more room for human error.  Moreover, the price of mass-produced products are lower due to lower labor costs and the lack of variation in the production.

            The parts of the electrical portion use several manufacturing categories, construction, semiconductors, plastics, and glass.  The solar panel’s mounting is construction and the solar panel is a semiconductors.  The UV housing is plastics, and the UV light is glass.

Science

Fig. 4 The breaking of the DNA

            UVGI, ultraviolet germicidal irradiation, uses short-wavelength ultraviolet light to kill microorganisms.  The light destroys the nucleic acids, which interrupts the DNA, seen in Fig. 4, nullifying the reproductive capabilities and killing the microorganisms.  Ashok Gadgil was the first person to use UVGI to purify water.  Without UVGI, the water the Unit creates would still contain pathogens and germs, defeating the purpose of creating clean water.

Fig. 5 The photovoltaic effect

             The photovoltaic effect uses light to create electricity.  Electrons ejected from the material jump between bands in the material, which creates a buildup of electrodes, as seen in Fig. 5.  The first person to discover this effect was Alexandre-Edmond Becquerel.  The photovoltaic effect is the principle behind solar panels, which the Unit relies on for power.

Fig. 6 Solar panels

Technology

            Since the Atacama region lacks infrastructure, the Unit needed to be independent of an outside power source.  A solar panel allowed for self-sufficiency and an environmentally friendly power source.  Solar panels use the photovoltaic effect to harness the sun’s energy to create usable electricity, see Fig. 6.  The amount of power created depends on the number of solar panels in the series. 

Fig. 7 the wing bolt, nut, and washer

Fig. 8 A hinge

            The solar panel mounting uses several technologies, including nuts, wing bolts, washers, and hinges.  Wing bolts, nuts, and washers interconnect.  The wing bolt is a cylindrical of fastener characterized by an external thread, wing bolts attach to a nut, which is a smaller piece with an internal thread.  A washer is often placed in between the wing bolt, nut, and the objects they are fastening, to stop the nut and wing bolt from wearing down the material.  Fig. 7 shows the wing bolt, nut, and washer along with the section of the base where the fasteners are located.  The mounting also uses two hinges; a hinge, Fig. 8, is a bearing that connects two objects together while allowing for movement on an axis.

Fig 9 An ultraviolet light bulb

 Germicidal UV light bulbs are Fluorescent lamps without a phosphorescent coating, which converts UV to visible light, and quartz with an additive that blocks the 185 nm wavelength.  For a picture of a typical UV light, see Fig. 9.  The UV light bulbs are the best way to administer UV radiation to water.

Fig. 11 The socket adapter

The UV light bulb inserts into a Medium to Intermediate Reducer Socket, Fig. 10, which is an adapter that changes the size of the socket and allows an intermediate bulb to screw into a medium socket.  The adapter screws into a light bulb socket, Fig. 11; a light bulb socket lets electricity run through a light bulb and light up.

Fig. 12 The bulb guard

The UV light is protected by a bulb guard, see Fig 12, a plastic structure that protects the bulb and opens to allow access to the bulb in case the bulb needs to be changed.

Math



            The size of the solar panel relates directly to the dimensions of the frame, see Fig. 13 for the cross brace.  The solar panel needed a range of 26°-74°, for New Jersey, and 40°-96° for the Atacama region, so the adjustable support piece need to be the correct length, see Fig. 14.  The amount of watts produced also had to match or exceed the amount needed, see Fig. 15. 

Fig. 13 The cross-brace

Fig. 14 The adjustable
support piece

Fig. 16 Watts are the rate at
which work is done

When designing the mounting, I used calculations based on a solar panel 15cm by 18cm.  I used the Pythagorean Theorem, a² + b² = c², see Fig. 16, to find the length of the cross-brace of the base.  I used the temporary size of the solar panel I had ordered to find the size, however, the sizes could be  wrong which would cause the numbers could change.  The size of the solar panel was 18cm x 15cm x .158cms, so the length of the cross-brace is 15² + 18² = c², 225 + 324 = c², 549 = c², √549 = √c², 23.4307 = c, so 23.4307 is the length of the cross-brace.  To find the optimum length for the adjustable support piece, I used trigonometry, see Fig. 17, to find the length that would allow both 26° and 74°.  I found the optimum length for the lowest position, 26°.  The most stable position for the arm would be would be the middle of the base, 7.5cm from the hinged end, and 14cm as the furthest practical point at which I can drill.  I then used the Law of Cosines, c² = a² + b² - 2 * a * b * cos(C), c² = 7.5² + 14² - 2 * 7.5 * 14 * cos(26), c² = 56.25 + 196 - 210 * 0.8988, c² = 252.25 - 188.7467, c² = 63.5033, √c² = √63.5033, c = 7.9689, so the optimum length for the adjustable support piece would be 7.9689.  For the watts, I used w, watts produced, and n, watts needed, in the formula w ≥ n, see Fig, 18.

Fig. 16 The Pythagorean theorem

Fig. 18 A visual explanation
of how inequalities function

Conclusion

Fig. 17 A standard triangle
used for trigonometry

The Desalination Unit is an open, technological system, which uses Electrical, Environmental, and Mechanical engineering.  Mass-production that focuses on construction, semiconductors, plastics, and glass, would be the most effective for the Unit.  The final solution is a small solar powered desalination unit, that utilizes solar humidification and UV radiation to ensure that the water cleaned is entirely potable.  The most important technology used in the electrical portion of the Unit would be the solar panel and the UV light bulb.  Furthermore, these technologies need the science of ultraviolet germicidal irradiation and the photovoltaic effect to back them up.  A fixed mounting would hamper the solar panel’s ability to function properly.  Without Science, Technology, Engineering, Manufacturing, and Math, the Desalination project would not be feasible.  The problems in the Atacama region are real, and are not limited to the area.  A person dying because they have to drink from dirty unsanitary water is not acceptable.  Unclean water can carry hundreds of parasites and can lead to numerous diseases.  The Desalination Unit gives people a clean source of water, and does this in an environmentally friendly way.  The Unit is a step towards saving people and the environment.

Works Cited

. "Construction." Wikipedia. N.p., 10 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Construction>.

. "Electrical engineering." Wikipedia. N.p., 19 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Electrical_engineering>.

. "Environmental engineering." Wikipedia. N.p., 9 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Environmental_engineering>.

. "Hinge." Wikipedia. N.p., n.d. Web. 29 Jan 2012 <http://en.wikipedia.org/wiki/Hinge>.

. "How do Photovoltaics Work? ." NASA. N.p., n.d. Web. 22 Jan 2012 <http://science.nasa.gov/science-news/science-at-nasa/2002/solarcells/>.

. "Inequality (mathematics)." Wikipedia. N.p., n.d. Web. 29 Jan 2012 <http://en.wikipedia.org/wiki/Inequality_(mathematics)>.

. "Mass production." Wikipedia. N.p., 20 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Mass-production>.

. "Mechanical engineering." Wikipedia. N.p., 20 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Mechanical_engineering>.

. "Photovoltaic effect." Wikipedia. N.p., 17 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Photovoltaic_effect>.

. "Plastic." Wikipedia. N.p., 16 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Plastics>.

. "Push-Button Socket Lamp Holder-R50-06098-0PG at the Home Depot." Home Depot. N.p., n.d. Web. 29 Jan 2012 <http://www.homedepot.com/Lighting-Fans-Indoor-Lighting-Indoor-Lighting-Accessories/h_d1/N-5yc1vZbvlmZ12kx/R-100357000/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053>.

. "Pythagorean Theorem." About.com. N.p., n.d. Web. 22 Jan 2012 <http://math.about.com/od/pythagorean/ss/pythag.htm>.

. "Renewable And Alternative Energy Solutions." ecofuture. N.p., n.d. Web. 22 Jan 2012 <http://ecofuture.net/energy/>.

. "Satco 92-322 Medium to Intermediate Reducer Socket." 1000bulbs.com. N.p., n.d. Web. 29 Jan 2012 <http://www.1000bulbs.com/product/5833/ELEC-242505.html>.

. "Screw." Wikipedia. N.p., n.d. Web. 29 Jan 2012 <http://en.wikipedia.org/wiki/Screw>.

. "Semiconductor." Wikipedia. N.p., 15 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Semiconductors>.

. "Solar panel." Wikipedia. N.p., 17 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Solar_panels>.

. "The Law of Cosines." Math is Fun!. N.p., 2011. Web. 29 Jan 2012 <http://www.mathsisfun.com/algebra/trig-cosine-law.html>.

. "The Ultraviolet Light Bulbs Objective." Ultraviolet Light Bulbs. N.p., n.d. Web. 22 Jan 2012 <http://ultravioletlightbulbs.org/the-ultraviolet-light-bulbs-objective/>.

. "Ultraviolet." Wikipedia. N.p., 21 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/Ultraviolet>.

. "Ultraviolet germicidal irradiation." Wikipedia. N.p., 10 Jan 2012. Web. 22 Jan 2012 <http://en.wikipedia.org/wiki/UVGI>.

. "Ultraviolet Light." penguinaircool. N.p., n.d. Web. 22 Jan 2012 <http://www.penguinaircool.com/air-conditioning-repair-AC-Service/HVAC-AC-ultraviolet-lights.html>.

. "Watt." Wikipedia. N.p., n.d. Web. 29 Jan 2012 <http://en.wikipedia.org/wiki/Watt>.