On April 17th we presented our lab to the hot dog cooker (solar parabola) group. The group responded well and reacted as if they understood which was a great sign. We ran into some minor issues with opening the graphing program- excel, however these things are expected when operating on relics of computers. So, the computer situation slowed us down but did not effect the results. The results were true to what was expected:
On April 24th we were paired with the solar parabola group once again. This time around the group was flying solo with the presentation. We saved some paper- GREEN- by setting the group up with our lab handout via the internet. Yes, we saved some paper. And it worked quite well, although we had to set the group up with cups of water and help to build the overall peltier device, the group was once again successful. The results were on point- and the outcome was nothing of a surprise.Of course the computer situation was rather frustrating- none the less, it was a success.
Final overview: The Peliter device was simply built and simply utilized. The group was able to really construct a vision of how the device could be used as a sustainable construction. We certainly grasped the fact that-if the device were larger and “more in charge”- it could be potentially expensive. With some help from Tom Vales we were able to push our device into motion and feel comfortable with how it worked. Alas, we understand how such a little invention could make a difference with sustainability.
Title: The effect of temperature differential on voltage using a Peltier Device.
Purpose: To see that the electricity generated by a Peltier Device increases as the input temperature differential to the device increases.
3. Background:
The Peltier Device was developed by French physicist Jean Peltier in the early 1834. The device uses the convergence of temperature differential translated to electric current. It is most commonly used for cooling devices ranging from portable coolers to military grade electronics.
This is relevant in sustainability because it helps increase energy efficiency. It does this by increasing the total energy output from a given input. For example, burning one gallon of gasoline creates X amount of energy. Not all of X goes directly into powering a motor, however. Some of it becomes heat. That heat can then be used to power a Peltier Device. Now you have produced more usable energy than you would have from that initial X amount of gasoline. The electricity from the Peltier Device could be used to power some other part of the car, ultimately saving energy.
4. Procedure:
Setup:
1. Place two Styrofoam cups next to each other.
2. Fill one with hot water, preferably from a coffee machine or tea pot (close to boiling).
3. Fill the other one with cold water, preferably adding ice and salt. The Peltier Device should fit inside of two pieces of metal.
4. There should be silicon, for adhesive and heat conducing purposes, on each side of the device.
5. The metal pieces should be bent/curved/shaped so they can each fit int one of the cups, and be joined by the device at the top.
6. Connect the two wires from the Peltier Device to a voltage reader.
7. Connect the voltage reader to the Lego MindStorm device via cords (that look like phone lines).
8. Also connected to the MindStorm device should be two thermometers. Each should be placed in one of the cups.
9. The MindSorm Device should connect to Labview via a USB cable.
10. In Labview it is necessary to create a program to take the right measurements. The program should simultaneously record the voltage from Peltier Device and both temperatures.
11. Run the program so that it takes from 20-30 measurements.
12. Take the average of the voltage measurements and record them in the appropriate space.
13. Do the same with temperature differential. Allow some time to pass for the temperature differential to decrease. You can add ice to the hot water, or vice versa to speed the process.
14. Continue to run the program and record the measurements 2-3 more times.
15. Then graph the averages with the X-axis being temperature differential in Degrees F and the Y-axis being voltage generated.
5. Data:
6. Analysis:
Graph the average voltage as a function of temperature differential. (X-axis is temperature differential and Y-axis is Voltage).
The French physicist, Jean Peltier, who lived from the years of 1785- 1845, created the Peltier device. He mastered the innovative technique of the calorific effect of electric current through friction between two different metals. This is now deemed the Peltier Effect. There needs to be two different junctions available for the heating or cooling process to occur. For the times, Jean Peltier was very successful. Although the device was more expensive than alternative energy production it was much better for the environment. Jean Peltier: An Environmental Man!
“The Peltier technology works in a particularly economical and energy-saving manner at temperatures close to ambient temperature, since energy is only required if heating or cooling is needed, in contrast to compressor technology. Very fine adjustments can be made here to the heating or cooling functions.”
“In heating operation, in the same way as in a heat pump, thermal energy is removed from the ambient air and introduced into the inner chamber. Because of the closed Peltier cooling system, no outside air is exchanged. The advantages: No de-humidification of the inner chamber and a notably reduced risk of contamination.”
In today’s world the Peltier device and thermoelectrical technology is used in many components. This technology can be found in camping equipment, portable coolers, and small instruments. Surprisingly, electronic equipment intended for military use on the field or in battle is thermoelectrically cooled. The cooling effect of the Peltier heat pumps can also extract water from the air in dehumidifiers. Photon detectors within some astronomical telescopes or expensive digital cameras are usually cooled down with Peltier devices. Generally the Peltier device is used in the chilling of beverages. Excitingly, some products can also reverse the current to heat the beverage as well. There are many A/C car adapter coolers and even USB beverage coolers which use the Peltier device.
Here is an outline of our lab, what we hope to achieve, and how we hope to do it.
Purpose:
Can we generate electricity by exploiting temperature differentials in water?
Introduction:
By using a basic Peltier Device, we should be able to generate an electrical current using only water and a minimal amount of other materials. We expect to find that by creating a larger temperature differential we will be able to produce more energy. As the temperatures differential naturally closes, we expect the voltage to decrease. We also expect to generate enough energy to turn on a light or a small string of lights.
Materials:
Two plastic cups. Water. Wires. Lego Mindstorm Software. Lego Mindstorm voltage recorder. Lights. Metal panels.
Procedure:
First we will gather and set up the materials. The two cups will sit next to each other. One cup will be filled with hot water, one with cold. We will place the adjoining metal plates over the two cups so that one panel is sitting in each of the cups. The heat and cold from the water will cause the entire panel to get hot or cold. The Voltage Recorder will then sit in between the two panels. The heat differential will create a current in the voltage recorder. This is then connected to the MindStorm software via a USB cord. The wires will then continue form the recorder to the light(s). We will measure the temperature of the water and the voltage simultaneously. Then we will wait for a yet-to-be-decided increment of time and record again. We will be graphing electricity generated versus temperature differential, temperature of hot water cup, and temperature of cold water cup.
Tom Vales, who works in electricl and computer engineering, came to visit us in our classroom. He brought with him several different machines that generate electricity to run motors. The first machine he brought is called a Peltier motor. The Peltier device, named after the French physicist of the same name, uses heat differential to generate electricity. This works by placing one wire in a cup of hot water and another in a cup of cold water adjacent to it. Charge carriers diffuse from the hot side to the cold side of the wire creating a current. The electricity then causes the a fan at the top to turn. The next machine we saw was a hot water engine. This engine converts heat energy directly to mechanical energy. The Mendocino Motor works using solar energy. He fixed a light so that it would shine on a solar cell. The cell converts light into usable electricity. There is a wooden shaft with a four magnets around the middle of it. He places the wood above another magnet (and between two hoops at each end, for guidance). The magnet at the bottom repels the magnet attached to the wood and causes it to turn 90 degrees. The repetitive, continual 90 degree turns makes the wood essentially spin and hover in the air.
The final machine he showed us was the Tesla Coil. This was much larger than the others, standing perhaps 5 or 6 feet tall. MR. Vales’ coil is made of a plastic bucket with wire wrapped around it, sitting on a wooden cart, with an antenna on top. The machine creates a high voltage of electricity but at a low frequency. The low frequency is important because that makes the light visibly purple to us. As Mr. Vales turns on the machine, it appears that lightening in shooting out of the top of the machine. He raises a photoluminescent light, which then ‘turns on’ due to the electricity in the air. The machine is used hypothetically for the wireless transferral of electricity, but in reality is mostly for entertainment and educational purposes.
