Environmental Science - Renewable Energy

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Environmental Science - Renewable Energy

Postby ssrivi » Mon Sep 16, 2013 5:34 pm

Hi,
I want to do something related to "Which types of renewable energy are most effective?" I can think of energy from cow manure and energy from topsoil. I could use some help finding maybe one or two more types and then how to test them. The other thing is how can I equally measure them? Using a large amount of one source will obviously generate more energy then a small amount of another. Is their any way that I could test with equal quantities so that my results will be accurate. If you have any other ideas that would be great. Please let me know when an answer is found.
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Re: Environmental Science - Renewable Energy

Postby Susan621 » Tue Sep 17, 2013 6:51 am

Ssrivi- I think it is wonderful that you want to do a project based on renewable energy sources. There are numerous renewable energy sources and I added some examples below. A quick Google search will provide you with a lot of information on each of these sources.

1. Solar Energy
2. Wind Energy
3. Hydropower
4. Biomass Energy
5. Hydrogen
6. Geothermal Energy
7. Ocean Energy

One of the sites I found in my Google search was for the US department of Energy’s Renewable Energy Site
http://www.eere.energy.gov/

The Science Buddies site is a great reference for energy project ideas. I attached the Links here.
http://www.sciencebuddies.org/science-f ... ower.shtml
http://www.sciencebuddies.org/science-f ... gy&d=4,5,6

Good luck with your project
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Re: Environmental Science - Renewable Energy

Postby heatherL » Wed Sep 18, 2013 8:35 am

Hi ssrivi,

Susan has already provided you with some great advice. I just wanted to address your question about how to compare amounts, which is a good question!

When you ask what is most "effective," then you will want to know what will generate the most energy for the amount you attempt. Another way to think about it is the amount of energy generated for the cost. Most companies are concerned with the cost of trying different types of energy, so showing that one type is cost-efficient is a good way to go.

In the end, you may not be able to standardize things exactly if the energy comes from different sources (which is why cost is a good way to compare things); but as long as you measure everything carefully (surface area of a solar panel, weight of cow manure, etc.), you can compare similar types with measurements they have in common.

I hope this helps. Please post again (in this same thread) if you have more questions.

Heather
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Re: Environmental Science - Renewable Energy

Postby ssrivi » Tue Nov 05, 2013 5:50 pm

Thank you very much. As I had few limitations (on using few products), I changed my idea towards generating power from Mud. I would appreciate if somebody could help me in using a Digital Multimeter. My Multimer (Commercial Electric - MAS830B -Green color) has

DC Voltage range (200mV,2V,20V,200V,600V)
DC Current range(20µA,200µA,2mA,20mA,200mA,10A)
AC Voltage range(200V,600V)
Resistance range(200Ω,2kΩ,20kΩ,200kΩ,2MΩ)
Diode

I am right now getting a good range of reading when I place Multimeter at the DC Current range(20mA). I want to know if I am correct. Can you help please..

1. Where do I need to place the rotary switch to select the correct range to be measured?
2. Some reading starts in a value and keeps decreasing. What should I do in this case. Do I need to have the start reading or the ending reading?
3. What is the ideal time to hold the test leads for each test?
4. When do I know the values are ready to add salt to test for the power?

I am doing this test with five different resistors
Here is the link to my project: http://www.sciencebuddies.org/science-f ... #procedure

Thanks.
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Re: Environmental Science - Renewable Energy

Postby SciB » Sun Nov 10, 2013 6:53 pm

Hi ssrivi,

That’s a pretty cool project—getting electricity out of dirt! There’s a lot of dirt out there.

I read the Scibuddies procedure for the project and I think I understand it. Here are my answers to your specific questions:

1. The voltage you will be measuring across the leads of the MFC is in millivolts, mV, so you set the range switch to 200 mV.

2. The instructions tell you to wait at least 30 minutes after putting on each resistor to allow time for the circuit to stabilize. When reading the voltage it may fluctuate up or down, but try to read it when it has stopped changing for a few seconds. You could try letting the system rest for an hour or so then doing the V readings again so you could get the average of two readings. Three would be even better.

3. There is no ‘ideal’ time. You have to hold the leads on the MFC contacts until you can get a stable V reading.

4. I’m not sure if this answers your question, but here’s the part of the procedure that refers to when you start adding the salt to the soil:

d. • After about ten to 12 days, the power output should stabilize.
i. It may stabilize anywhere between 5 µW to 200 µW or more. A lot depends on the topsoil you are using and other factors. Wherever it stabilizes, it should make enough power to blink the LED at least once every 30 seconds.
ii. When it stabilizes, the peak power should not change by more than about 0.5 uW for at least three days in a row.
iii. Do not worry if your peak power changes by a little more than this. If it has been about ten to 12 days and the peak power is not steadily increasing each day, then it has probably stabilized enough.
iv. Tip: Making a graph of your data as you collect it may help you see if the power output is stabilizing. If you do this, put the date on the x-axis and the power output (peak power) for each day on the y-axis. Does the peak power appear to be stabilizing?
v. The time between LED blinks should also stabilize.
• Once it appears that the power output has stabilized, carefully open up the MFC and mix in ¼ teaspoon (tsp.) of salt throughout the mud.
a. Take your measurements for the day as usual before adding the salt.

I hope I have answered your questions OK. If not let me know and we will continue to help you.

Good luck!
Sybee
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Re: Environmental Science - Renewable Energy

Postby ssrivi » Thu Nov 14, 2013 7:36 am

Thank you very much.
That works.
Last edited by ssrivi on Sun Nov 24, 2013 11:13 am, edited 1 time in total.
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Re: Environmental Science - Renewable Energy

Postby SciB » Thu Nov 14, 2013 2:53 pm

Hi ssrivi,

Glad to hear your mud-pie battery is working so well. I would say 141.9 mV is a respectable output at 1000 ohms!

To use the formula P = Vsquared/R you just have to know that the voltage has to be in VOLTS, not millivolts. So, your V = 0.142

Resistance, R, has to be in ohms, which you said was 1000 for this V reading.

So, P = 0.142x0.142/1000 = .0000202 watts

The values you want should be in microwatts, so you need to multiply your watt calculations by 1,000,000 because there are 1 million microW per W.

The answer would be 20.2 microW.

I don't know what's going on with the blinking LED, but keep doing the voltage readings with the different resistances and when you plot microW vs R, you should get a pretty good straight line. If you use MS Excel to graph your data, make it a scatter plot and you can do a linear regression analysis on the line that will show how well the fit is. I can show you how to do that if you don't know. Also, if any of your microW calculations look too far off, there's a statistical formula you can use to test for error.

Good job and keep posting!

Sybee
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Re: Environmental Science - Renewable Energy

Postby ssrivi » Sat Nov 16, 2013 8:39 am

Thanks Sybee,

The blinks in the LED started with 1 min and 15 seconds apart on the 6th day and gradually reduced to 2 sec apart on the 15th day with just top soil. I added salt on the 15th day and when i checked the reading on the 18th day the LED blink moved up to 5 Sec apart. Is this normal? I was assuming the salt would increase the power output but so far its not. Did anything go wrong?

Thanks,
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Re: Environmental Science - Renewable Energy

Postby SciB » Sun Nov 17, 2013 1:06 pm

Hi ssrivi,
Did you measure the power after you added salt? The LED blinks are a rough indicator of power, but you should still do the voltage measurements to calculate microwatts.

I read back over the procedure section in the Scibuddies project and there are a couple of things that could affect the output after the salt is added. The salt needs to be mixed into the soil well but when you are doing that you have to be careful not to get mud on the cathode or disturb the anode. See below:


“Sprinkle some of the salt on top of the mud, mix it in, and then dig around inside of the mud, adding salt and mixing it in as you go. You want to mix the salt as evenly into the mud as possible, but do not disturb the anode - leave it in place (as well as its wire and the mud below the anode).
i. Note: Disrupting the anode could damage the developing biofilm and interfere with your results.”

Do the power calculations and see what you get. The timing seems to be a bit fussy. The instructions say that the power will increase the day after the salt was added but then may decrease and stabilize 4-5 days after adding salt—so you should take readings every day.

Is the temperature fairly constant where you have the MFC? Since this is a chemical/biological reaction, temperature will affect the rate and thus the electrical output. Try adding another ¼ tsp of salt and take readings again over 5 days, graphing the peak power output vs the days to see if it looks like it is stabilizing.

Good luck with your experiments and do keep us posted about your progress.

Sybee
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