Archive for December, 2009

How does the solar battery charged using solar panels?What is the mechanism that converts solar energy in to electrical energy? How can a car be run on solar energy?what could be its maximum speed?

The mechanism used to convert solar energy is called a photovoltaic cell.
Solar cells are built of a mostly silicon compound, which leaves some atoms with loose electrons. These electrons are knocked free by the energy of the sun and, if attached to a circuit, will charge the battery like any AC charger.
A car can be run very simply Just use an electric car, with batteries being charged by a solar panel on the roof or at a filling port (similar to a gas station).
The fastest solar car I know of is the Nuna 2 (105 mph)

Hope this helps

I’m an engineering student and for an individual hobby-like project i purchased a small solar panel and a small solar motor. I am planning on making a small solar powered toy car. The question i have is: is there a way to connect a control or some other ways of regulating the power that is absorbed by the cells? Other wise the motor will just continue to run. Any answer would be greatly appreciated. Thanks!

I assume it is a DC motor. You should have DC voltage coming out of the solar cell (For example 10V). You could use a transistor to switch the voltage on and off, then filter the output with an RC filter. You will have to choose the right RC time constant . It will have to be slower than the control pulse frequency, but faster than the desired motor response time.

If you switched the voltage with a 50% duty cycle, then filtered the output, you would get 5V, with a 75% duty cycle, you would get 7.5V, etc. Therefore, you could control the motor by controlling the duty cycle of the switching. A microcontroller like the BASIC Stamp can produce the control pulses.

I want to do a science project where I create my own solar panels out of different materials to see which one will produce the greatest amount of energy. Is this a realistic topic if it has to be done before Thanksgiving? If so, how do I make the solar panels? How do I measure/convert the energy? Please help!

Your best bet is making solar water heating panels. You could make them out of copper, PVC, and garden hose, and compare which gets hotter. Check out this site for ideas. http://www.builditsolar.com/

Avoid the scams out there saying you can build your own panel for $200 to power your whole house. You can’t. There are some free instructions on the You Build It site that are legit.

I know the cost of how much solar panels are but what is the price to install them?If I were to install about 10 on a building?

Hello! That is great that you are thinking of installing solar panels. Just to be clear, I believe you are talking about solar panels to produce electricity, aka photovoltaic panels. As mentioned in previous answers, the cost of installation will vary depending upon your location. But a good estimate is $7-$10 per Watt for a grid-tied, battery-less system.

So if you installed 10-200 Watt solar panels, that would be 2000 Watts (2 kW) and cost approximately $14,000-$20,000 before rebates and incentives. Be sure to check for local rebate programs and read about the 30% federal tax credit here:
www.dsireusa.org

Good luck!
Kristen

http://newenglandbreeze.com/

By alternative energy sources I mean things like solar, wind, nuclear, geothermal, hydroelectric, etc. I want to see how efficient they are, not really paying attention to how polluting they are.

You can’t make a meaningful comparison that way.
A coal plant, for example, may have 30% thermal efficiency. The coal it burns, though, comes from plants that had only about a 2% efficiency in turning sunlight into biomass. A nuclear plant using the same steam technology as a coal-fired plant has about the same thermal efficiency, but involves far less fuel – indeed, some nuclear plants make more fuel than they use.
Thin-film solar panels are only about 1/5 as efficient, area for area, as standard silicon solar panels, but cost about 1/10 as much. Either panel has far higher overall efficiency than a coal-fired plant, but involves manufacturing costs that makes their electricity more expensive if subsidiary costs (like adverse health effects) are neglected.
Relative availability of energy is also an issue. Solar and wind aren’t always available. A hydroelectric dam becomes useless if the river feeding its reservoir dries up.
The wiki article referenced discusses relative costs of electricity produced by various methods.

I have a small panel of solar cells, i wish to save this energy for lighting my study lamp, how do i do it?
How much energy will it hold? How do i convert it to light?
Please help friends.
Thanks

You will need a way to store the energy gained my solar panel.

Way 1, 12 volt battery. to store this way, I suggest a regulator to prevent your battery overloading, though this is not always needed. This is the most common way.

Way 2, wire up a capacitor. this is a type of temporary battery, as it stores electrical charge and releases it on its full capacity. This way is good if you want lighting in a cellar during daytime

Way 3, use the electric you gain to pump water to a high point and then use gravity to create hydro electric whenever you need it. This way works, but you lose energy.

If you want to run lights off a battery, you will need some 12 volt bulbs, as these work of different electricity than normal household bulbs. You can cheat and use car head light bulbs, or go for the real things and buy proper 12 volt bulbs to fit a lamp-stand.

Unless you disconnect your household light circuit from the mains, you will need an extra set of wiring.

In short, the most simple way, if you put your panel in the window, lead the two wires to your battery, ensuring you connect each wire to the correct terminal (the panel will instruct which is which). From the battery, take a wire off each terminal and fix to the light bulb holder, and an extra wire from the negative battery terminal to an earth source, such as a copper water pipe. Don’t worry, it wont electrocute you – there isn’t enough power for that.

Simplifying it, wiring a light bulb is just like wiring a car. The same applies to both. The only difference being that you charge your battery via a solar panel instead of an alternator.

How long your light will stay on will depend on a multitude of things, such as the condition of your battery, the power output of your panel, how many lights you run and for how long. The amount of sun that hits your panel will also affect the charge rate of your battery. ?And there are many different types of battery. I personally recommendd the armed forces surplus alkaline type, as they can be depleted of charge without damage, though if you cannot get one of these, get a long life leisure battery.

It all sounds complicated, but it’s not really. Contact me if you need more help…

The solar panel wouldn’t need to be very large, and for the most part could be on the back or top of the street light. At night, they could be powered the same way they are now or by batteries that the solar panels could be charging throughout the day. Please explain to me if you think this is good or bad.

China already does this on all new install in many parts of the country. It is a small panel with LED lights, they work fine.

At school, we did an experiment where we calculated the temperature of different geothermal properties, to see if the school would have a good source of solar energy.

In the discussion questions, it says:
Set up a proposal to use solar energy energy for out school (3 external uses).

I have noo idea what I’m doing. If anyone could help that’d be great!

Yeah!! Solar in Schools is great! Here are some thoughts. There are a LOT of community grants for Green Schools. Many schools are putting solar electric (PV) arrays on their school in order to reduce their electrical bill and inspire students and the community. This can be a pretty costly proposition – $50,000 to $500,000 – so that may be difficult to make an argument for. If you want to demonstrate solar power in conjunction with reducing waste – check out a solar trash compactor from Big Belly Solar ($3000-$4000 each).

Technical High Schools are setting up labs for solar hot water and solar electric PV – this is a great way to train the future work force AND expose students to the technologies.

Finally, encourage your teachers to explore lesson plans to bring solar and wind technologies into the classroom:
K-12 Lesson plans – http://www1.eere.energy.gov/education/lessonplans/
CO – Solar in School s- http://www.solarenergy.org/solar-schools-sis
CA – http://www.need.org/pgesolarschools/

Keep up the good work!
Kristen

http://newenglandbreeze.com/