Difference between revisions of "Sustainable Energy Vehicle Competition"

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== Objective ==
= Objective =
The experimental objective is to evaluate different types of energy storage and different sources of renewable energy. Design a sustainable energy vehicle using the power sources and power storage devices provided in the lab to compete in a competition within the section.


== Overview ==
The experimental objective of this lab is to evaluate different sources of renewable energy and use the results of that evaluation to design a vehicle that is powered by a renewable energy source or a capacitor that is charged by a renewable energy source. The design will be entered in a competition that is judged by a ratio that uses distance traveled, travel time, and cost. The highest ratio wins.


=== Energy Storage ===
= Overview =


==== Electrolytic Cells ====
From sails to power boats, windmills to pump water, or water-driven wheels to power machinery that mills grains, humans have been using renewable energy sources for millennia. A significant amount of our energy production comes from non-renewable resources, such as oil, natural gas, and coal. The detrimental effects on public health and the environment from burning fossil fuels have prompted greater interest and investment in renewable energy sources, including solar, wind, and hydroelectric power though hydroelectric power is not considered in this lab. Scientists and engineers must address concerns about the inability of some renewable sources, notably solar power and wind power, to generate power consistently so there is equal interest in developing energy storage devices that can operate at grid-scale or hold sufficient energy to power entire communities for an extended time after being charged by a renewable energy source.
A battery is a device that is usually made up of one or more individual cells. In this experiment we will be creating a citrus cell. A battery cell is a cell that creates a voltage across a terminal of two dissimilar metals. This is done through a chemical half reaction. A citrus cell is one that does this using a citrus juice as the electrolytic solution. By using two different types of metals we have two different reaction potentials which directly affect the voltage produced with each cell. By linking multiple cells together in series we produce a battery.


Before learning the concept behind a battery cell, there are two properties that should be understood: electronegativity and ionization energy:
== Types of Renewable Energy ==


* '''Electronegativity''' in an element is a measure of the element's capability to attract another element's electrons. The higher degree of electronegativity an element has the more power it has to pull away electrons from a less electronegative element. There is an obvious trend in the periodic table for this particular property. Electronegativity generally increases from left to right and from bottom to top. As a result the elements around cesium have very low electronegativity and elements around fluorine have the highest.
<b>Renewable energy</b> is a type of energy that can be harnessed from naturally replenished resources. Some examples of this are sunlight, wind, and water. There are many benefits to using renewable energy. They are clean energy sources, and they come from abundant sources that do not become depleted. If these renewable resources can be harnessed effectively, they can solve the problems with using non-renewable energy sources (NextEra Energy Resources, 2012). In the last few years, renewable energy has been the fastest-growing energy source globally (International Energy Agency, 2021). In this lab, solar and wind energy will be used.  


* '''Ionization energy''' is the amount of energy required to remove an electron from an atom to form a cation. A cation is an ion or group of ions having a positive charge in electrolysis. This property also has a trend in the periodic table. It generally increases from left to right and from bottom to top.
=== Solar Power ===


[[Image: lemonlab_1.jpg|frame|center|Figure 1: Periodic Table Overview]]
Sunlight, like any other type of electromagnetic radiation, contains energy. Typically, when sunlight hits an object, the energy that it contains is converted into heat. Certain materials can absorb and convert that energy into an electrical current. In this form, sunlight can be used as a power source or stored for later use.


<p>The electronegativity and ionization energy values for the metals used in the
<b>Solar panels</b> are devices that generate electrical current from sunlight. The panels contain a crystalline material that absorbs and converts the sunlight into electricity. The crystalline material has a repeating structure formed by a network of covalent bonds where electrons are shared by atoms within the crystal. Traditional solar cells are made from crystalline silicon.
lab are provided in the table below:</p>


<table border=1 cellspacing=0 align=center>
To produce a current, there must be a difference in the concentration of electrons between one area and another to cause their flow. In a silicon solar cell, a concentration difference is created using two types of silicon, <b>p-type</b> and <b>n-type</b>. The p-type silicon is created by adding atoms, such as boron, that have one fewer electron in their valence energy level than silicon has. As a result, a vacancy of electrons, or a hole, forms. The n-type silicon is created by adding atoms that have one more electron in their valence energy level than silicon has so that there is an excess of electrons that can move around the crystal structure and create an electrical current. In a solar cell, p-type and n-type silicon are sandwiched together to create a <b>p-n junction</b>, as shown in Figure 1 (Locke, 2008). The p-type area is positively charged, and the n-type area is negatively charged.  
<tr>
<td><b>Metal</b></td>
<td><b>Electronegativity<br>(Pauling Scale)</b></td>
<td><b>Ionization Energy<br>(kJ/mole)</b></td>
</tr>
<tr>
<td>Magnesium</td>
<td align=right>1.31</td>
<td align=right>738</td>
</tr>
<tr>
<td>Nickel</td>
<td align=right>1.91</td>
<td align=right>736</td>
</tr>
<tr>
<td>Copper</td>
<td align=right>1.90</td>
<td align=right>745</td>
</tr>
<tr>
<td>Zinc</td>
<td align=right>1.65</td>
  <td align=right>904</td>
</tr>
<tr>
<td>Aluminum</td>
<td align=right>1.61</td>
<td align=right>577</td>
</tr>
</table>


The reaction that takes place in the lemon cell is called a redox reaction. This reaction can be simplified into two parts and they are called oxidation and reduction. Oxidation happens when there is an electron loss and reduction is when there is an electron gain. Oxidation and reduction can be shown in a half-reaction, which clearly shows the electron transfer. Take for example the redox reaction between magnesium and oxygen.
When sunlight hits the silicon on the solar panel, the photons from the sunlight energize the electrons in the material. The electrons within the crystal move to a higher energy level, creating holes. If the p-type and n-type silicon are connected with a wire, the electrons will flow from the n-type layer to the p-type layer, and electrical current is generated.


<math>2Mg(s) + O_2(g) \rightarrow 2MgO_2(s)</math>
[[Image:Lab_renewener_01.png|thumb|500px|center|Figure 1: A Silicon Solar Panel Showing the Electron Flow]]


When magnesium reacts with oxygen, magnesium loses electrons making it oxidized:
Other materials have been used in the production of solar panels. Panels made from copper indium gallium (di)selenide (CIGS) have a smaller crystalline structure and are less expensive than silicon. CIGS panels are relatively flexible and can easily be shaped into flexible films. The use of CIGS to make solar panels is referred to as thin-film solar technology because of its flexible nature. CIGS panels are not as good at converting absorbed light into electrical current compared to silicon, but for mass production purposes, CIGS solar panels are the more cost effective approach to produce solar panels for frequent use (Locke, 2008). In the last decade, perovskite materials have also received attention for thin film technologies because of their competitive efficiency (Dey <i>et al</i>., 2021).


<math>Mg(s) \rightarrow Mg^{2+}(s) + 2e^-</math>
=== Wind Energy ===


At the same time, oxygen gains those electrons making oxygen reduced.
<b>Wind turbines</b> are used to capture the wind’s energy and convert it into electrical energy. The blades on wind turbines are slanted so that as the wind passes over the blades, it creates an uneven pressure on each side, causing them to rotate. The spinning blades drive a low speed shaft connected to a gearbox. The gearbox converts the low speed rotation to a high speed rotation through a high speed shaft. The high speed shaft is connected to a brake and then into an electrical generator where mechanical energy is converted to electrical energy (Layton, 2011).


<math>O_2(g) + 4e^- \rightarrow 2O^{2-}(g)</math>
A basic electrical generator is made of permanent magnets on each side with a rectangular coil connected to a commutator, which is a rotary electrical switch (Figure 2). The two permanent magnets on each side create a magnetic field. As the rectangular coil spins mechanically, the magnetic field through the area of the coil changes, creating an alternating current through the coil. The commutator switches the polarity of the coil just as the polarity of the alternating current changes, creating a direct current. The current is then output from the wind turbine (Layton, 2011).


==== Hydrogen Fuel Cells ====
[[Image:Lab_renewener_02.png|thumb|500px|center|Figure 2: The Internal Structure of an Electrical Generator (Layton, 2011)]]
A fuel cell is a power storage device which stores chemical energy and converts it into electrical energy. The fuels used can range from hydrogen, methane to even gasoline. For the purpose of this lab we will be using hydrogen as a fuel; therefore we are using hydrogen fuel cells. The main components that make up the fuel cell are an electrolyte, an anode chamber, a cathode chamber, and bipolar plates. The electrolyte acts as a separator that keeps the reactions from interacting with each other, by separating the anode and cathode chambers. When the water molecules are broken down, the hydrogen is stored in the anode chamber and oxygen on the cathode chamber. The bipolar plates collect the current generated by the fuel cell when the reaction takes place. Refer to Figure 3 for the internal structure of a fuel cell. [4]


Generally the gas used by the fuel cell is already separated prior to the use with a fuel cell using various methods such as using an electrolyzer, a device that separates distilled water into hydrogen and oxygen. In some cases fuel cells can be used to initiate this reaction, they are called reversible fuel cells. When supplied with water the reversible fuel cell separates the distilled water into hydrogen and oxygen. The stored hydrogen and oxygen can then be supplied to the fuel cell to generate electrical energy. Hydrogen fuel cells can be used to power various utilities such as computers, cars, power plants and even whole cities. However due to the nature of producing and storing the gas required to generate large amounts of electrical energy fuel cells are generally very large. This becomes a problem when being used in vehicles.
<!--==== Hydroelectric Power ====
Water is constantly moved around in various states through the water cycle. Water evaporating from Earth’s surface condenses into clouds. The water in clouds over land will eventually precipitate in the form of rain effectively transporting water to a higher elevation and thus potential energy state. The energy is then release in the form of water flowing downstream. This movement provides opportunities to harness a seemingly infinite source of kinetic energy. In order to generate sufficient electricity from the motion of the water, it has to move fast enough and in large enough volumes to spin a turbine. The turbines used for hydroelectric energy operate in an almost identical manner to the turbines for used for wind power. The only differences occur in the physical construction of the turbine itself. In order to increase the volumes and motion of the water dams are created to store reservoirs of water.
[[Image:Lab_renewener_03.png|thumb|500px|center|Figure 2: This is the internal structure of a fuel cell [4]]]<br style="clear: both;" />
 
Gravity causes the water held at the top of the dam to drop through the penstock (regulates water flow). At the end of the penstock is the turbine, which rotates thus creating the mechanical energy used to rotate the magnets in the generator.  
 
[[Image:hydropower1.png|thumb|800px|center|Figure 7: The hydroelectric process of a dam]]-->
 
== Energy Storage ==


==== Capacitors ====
<b>Capacitors</b> have many uses in circuits and signal processing. A capacitor is an electrical device that is used to store charge temporarily. Some capacitors can be used in place of a battery, but they operate very differently from a battery. A capacitor is charged by a voltage source logarithmically, as shown in Figure 3. In this lab, a capacitor will be used as the power source for the renewable energy vehicle.  
A capacitor is an electrical device used to store charge temporarily. Some capacitors can be used in place of a battery but they operate very differently from one. A capacitor is charged by a voltage source logarithmically, as shown in Figure 3.
   
   
[[Image:Lab_renewener_06.png|thumb|500px|center|Figure 3: Capacitor Charging Curve]]<br style="clear: both;" />
[[Image:Lab_renewener_06.png|thumb|500px|center|Figure 3: Capacitor Charging Curve]]


Because of their design, these capacitors are sensitive to the polarity of the voltage applied to them. The capacitors used in this lab must be connected with the proper polarity, or they will fail. Therefore, be sure to check the capacitor used to make sure you have the negative sign on the capacitor connected to the negative applied voltage. Failure to do this will cause the capacitors to fail.
Because of their design, capacitors are sensitive to the polarity of the voltage applied to them. The capacitors used in this lab must be connected with the proper polarity. In the lab, the capacitor’s negative lead must be connected to the negative applied voltage (Figure 4). Failure to do this will cause the capacitor to fail.
   
   
[[Image:Lab_renewener_07.png|thumb|500px|center|Figure 4: Polarized laboratory capacitor]]<br style="clear: both;" />
[[Image:Lab_renewener_07.png|thumb|500px|center|Figure 4: Polarized Capacitor]]


The total energy a capacitor holds is given by the equation ''E = CV<sup>2</sup> / 2''. Note that the energy that the capacitor holds is proportional to the '''square''' of the voltage.
The energy a capacitor holds is proportional to the square of the voltage across the capacitor (1).


=== Types of Renewable Energy ===
<center><math>E = \frac{CV^2}{2}\,</math></center>
Renewable energy are types of energy that can be harnessed from naturally replenished resources. Some examples of this includes sunlight, wind, and water. There are many benefits of using renewable energy such as clean energy sources, and they come from an abundant source that doesn’t become depleted. If we are able to efficiently utilize these renewable resources we can solve the problems with using non-renewable energy sources such as fossil fuels. [1]
<p style="text-align:right">(1)</p>


==== Solar Power ====
In (1), E is the energy, C is the capacitance, and V is the voltage.  
Sunlight, like any other type of electromagnetic radiation, contains energy. Typically when the sunlight hits an object, the energy that it contains is converted into heat. However, certain materials can convert the energy into electrical current, and in this form we can harness it and store it as energy.  


In a crystal structure, the materials used for solar panels contain covalent bonds where electrons are shared by the atoms within the crystal. When the light is absorbed, electrons within the crystal become excited and move to a higher energy level. When this occurs the electron has more freedom of motion within the crystal. When the electrons move around the crystal structure an electrical current is generated, this in turn gives us electrical energy. The reaction that occurs when sunlight shines onto a solar panel is shown in Figure 5. [2]
== Electrical Components ==


The design of a circuit determines its behavior. In this lab, one circuit design will increase the speed output of a motor and the other will increase the torque output of a motor. In electrical engineering, different electrical components are represented by different symbols. Figures 5 show the symbols for a <b>battery</b>, <b>DC source</b>, and <b>capacitor</b>. They are all forms of energy storage devices.


Older solar panels consist of large crystalline structures made from silicon. When sunlight hits the silicon on the solar panel, the photons from the sunlight energize the electrons in the material. These energized electrons create a higher electrical potential in the material, which is measured as a voltage between that material and ground. The silicon solar panels convert a large amount of the sunlight into electrical energy but are not cost due to high manufacturing costs.[2]
[[Image:Symbol_for_Capacitor_Battery_DC_Source.png|center|thumb|400px|Figure 5: (l-r) Symbol for Capacitor, DC Source, Battery]]


The material ''Copper indium gallium (di)selenide'' (CIGS) is also used in the production of solar panels. Panels made from CIGS have a smaller crystalline structure and are less expensive than their silicon counterparts. CIGS panels are relatively flexible and can easily be shaped into flexible films. The use of CIGS to make solar panels is referred to as thin-film solar technology because of its flexible nature. CIGS panels are in fact not as good at converting absorbed light into electrical current compared to silicon. However, for mass production purposes, CIGS solar panels are the more cost effective approach to produce solar panels for frequent use. [2]
Different arrangements of electrical components allow engineers to design different devices. Components, such as resistors, inductors, and capacitors, can be arranged in two different ways. In a <b>series circuit</b>, the element's components are connected end to end. The current in a series circuit remains the same in all the electrical elements (Figure 6).  


[[Image:Lab_renewener_08.png|thumb|500px|center|Figure 6: A Series Circuit]]


[[Image:Lab_renewener_01.png|thumb|500px|center|Figure 5: A solar panel made using silicon is shown to have a change of electron flow as photons are being absorbed by the plate.]]<br style="clear: both;" />
In a series circuit, as shown in Figure 6, the sum of the voltages across each element is equal to the voltage of the power source (2). Note that there is a singular path for current to flow through.


==== Wind Energy ====
<center><math>V_{out} = V_A + V_B + V_C</math></center>
<p style="text-align:right">(2)</p>


Wind turbines are used to capture the wind’s energy and convert it into electrical energy. The structure of a wind turbine has a heavy influence on its functionality. The blades on wind turbines are slanted so that as the wind passes over the blades it creates an uneven pressure on each side causing them to spin. The spinning blades in turn drive a low speed shaft connected to a gearbox. The gearbox within the wind turbine converts the low speed rotation to a high speed rotation through a high speed shaft. The high speed shaft is connected to a brake and then into an electrical generator where mechanical energy is converted to electrical energy. [3]
In (2), V<sub>out</sub> is the voltage output and V<sub>A</sub>, V<sub>B</sub>, and V<sub>C</sub> represent the voltage of the individual components.  


A very basic electrical generator is made up of permanent magnets on each side with a rectangular coil connected to a commutator, a rotary electrical switch. The two permanent magnets on each side create a magnetic field. As the rectangular coil spins mechanically, the magnetic field through the area of the coil changes creating an alternating current through the coil itself. The commutator switches the polarity of the coil just as the polarity of the alternating current changes creating a direct current. The current is then output from the wind turbine. [3]
In a <b>parallel circuit</b>, as shown in Figure 7, the circuit's components are connected at opposing ends. The current that is supplied by the voltage source equals the current that flows through elements D and E.  


[[Image:Lab_renewener_09.png|thumb|500px|center|Figure 7: A Parallel Circuit]]
[[Image:Lab_renewener_02.png|thumb|500px|center|Figure 6: The internal structure of an electrical generator [3]]]<br style="clear: both;" />


The voltage across the elements that are parallel is the same (3). In comparison to a series circuit, a parallel circuit has multiple paths for the current to flow.


==== Hydroelectric Power ====
<center><math>V_{out} = V_D = V_E</math></center>
Water is constantly moved around in various states through the water cycle. Water evaporating from Earth’s surface condenses into clouds. The water in clouds over land will eventually precipitate in the form of rain effectively transporting water to a higher elevation and thus potential energy state. The energy is then release in the form of water flowing downstream. This movement provides opportunities to harness a seemingly infinite source of kinetic energy. In order to generate sufficient electricity from the motion of the water, it has to move fast enough and in large enough volumes to spin a turbine. The turbines used for hydroelectric energy operate in an almost identical manner to the turbines for used for wind power. The only differences occur in the physical construction of the turbine itself. In order to increase the volumes and motion of the water dams are created to store reservoirs of water.
<p style="text-align:right">(3)</p>


Gravity causes the water held at the top of the dam to drop through the penstock (regulates water flow). At the end of the penstock is the turbine, which rotates thus creating the mechanical energy used to rotate the magnets in the generator.  
In (3), V<sub>out</sub> is the voltage output and V<sub>D</sub> and V<sub>E</sub> represent the voltage of the individual components.
A <b>digital multimeter</b> will be used in this lab to read the current and voltage across components in circuits. Please read the [[Digital Multimeters Guidelines]] before performing this lab in order to understand how to properly operate a digital multimeter. Digital multimeters can measure either voltage or current, indicated by the symbols shown in the circuit diagram (Figure 8).


[[Image:Symbol_for_Voltmeter_and_Ammeter.png|thumb|300px|center|Figure 8: (l-r) Symbols for a Voltmeter and Ammeter]]


[[Image:hydropower1.png|thumb|800px|center|Figure 7: The hydroelectric process of a dam]]
Depending on whether voltage or current is being measured in a circuit, the multimeter will be arranged in the circuit in a different manner. To measure the voltage across an electrical component, the multimeter must be placed in the circuit in parallel (Figure 9).


=== Electrical Components ===
[[Image:Multimeter_in_Parallel.png|thumb|362px|center|Figure 9: Multimeter in Parallel]]
In electrical engineering different electrical components are represented by different symbols. Below in Figures 7a and 7b are examples of symbols for a cell and a battery.
<div><div style="float: left; display: inline;">[[Image:Lab_renewener_04.png|center|thumb|500px|Figure 7a: Cell]]<br style="clear: both;" /></div><div style="float: left; display: inline;">


[[Image:Lab_renewener_05.png|center|thumb|500px|Figure 7b: Battery]]<br style="clear: both;" /></div></div><br style="clear: both;" />
To measure the current across an electrical component, the multimeter must be placed in the circuit in series (Figure 10). As described in the [[Digital Multimeters Guidelines]], ensure the leads are connected to the appropriate multimeter ports depending on which value is being measured.


A '''diode''' is a device that allows current to pass through it in only one direction. This means that it has polarity, and will only allow current to pass from its positive side to its negative side. A '''Light Emitting Diode (LED)''' not only passes current, but also lights up when it's passing current. LEDs have a forward voltage and a reverse voltage. In the forward direction, the forward voltage and resistance are low and determined by the material used in the LED. The reverse voltage has a much higher resistance and a higher reverse voltage that prevents the flow of electrical current. The characteristic of the diode is to have low resistance to electrical flow in the forward direction and high residence in the reverse direction provides the ability to control the flow of electricity in one direction only.
[[Image:Multimeter_in_Series.png|thumb|362px|center|Figure 10: Multimeter in Series]]


There is a threshold voltage in the forward direction for the LED to emit light. Below the threshold voltage, there is no light. At and above the threshold voltage the LED emits light with intensity roughly linear with forward voltage. The symbol for the LED is shown in Figure 8.
After measuring the voltage and current across a component in a circuit, the electrical <b>power</b> output of that component can be calculated using the Power Law (4).


[[Image:Symbol_LED.png|frame|center|Figure 8: LED Symbol<sup>3</sup>]]
<center><math>P = IV</math></center>
<p style="text-align:right">(4)</p>


Different arrangements of electrical components allow engineers to design different devices. Components like resistors, inductors, and capacitors can be arranged in two different ways. In a series circuit, the element's conductors are connected end to end. The current in a series circuit remains the same in all the electrical elements. In a series circuit, as shown in Figure 9, the sum of the voltages across each element is equal to the voltage of the power source (''V<sub>out</sub> = V<sub>A</sub> + V<sub>B</sub> + V<sub>C</sub>'').  
In (4), P is the power (Watts), I is the current (Amperes), and V is the voltage (Volts).
[[Image:Lab_renewener_08.png|thumb|500px|center|Figure 9: A series circuit]]<br style="clear: both;" />


In a parallel circuit, as shown in Figure 10, the element's conductors are connected at opposing ends. The current that is supplied by the voltage source equals the current that flows though elements '''''D''''' and '''''E'''''. The voltage across the elements that are parallel is the same (V<sub>out</sub> = V<sub>D</sub> = V<sub>E</sub>).
The motor provided in the lab is a 9 DC motor that will operate with voltages no more than 9 V with reduced torque and speed (Figure 11). A motor with no load operates under the current of 9 mA, and a stalled motor operates under the current of over 350 mA. Increasing the voltage provided to the motor increases the speed. Increasing the current, increases the torque.
[[Image:Lab_renewener_09.png|thumb|500px|center|Figure 10: A parallel circuit]]<br style="clear: both;" />


The motor provided is a 9V motor that will operate with voltages lower than 9V with reduced torque and speed. A motor with no load draws 9mA; a stalled motor draws well over 350mA. By increasing the voltage provided to the motor you can increase the motor speed. By increasing current you increase the torque.
[[Image:LEGO 9V Motor.jpg|thumb|200px|center|Figure 11: LEGO 9V Motor]]


== Design Considerations ==
= Design Considerations =
* Which source yields the most voltage per unit cost?
* Which source yields the most voltage per unit cost?
* Which type of energy storage is most effective?
* Which circuit configuration will provide the most voltage across the load? Parallel or series?
* Which circuit configuration will provide the most desirable voltage across the load? Parallel or series?
* Which aspects of the competition formula are most advantageous?
* Which aspects of the competition formula are most advantageous?


== Materials and Equipment ==
= Materials and Equipment =
=== Materials with Price List ===
=== Materials with Price List ===
* 2oz Lemon Juice (with cup): $0.50
{| class="wikitable"
* 1.5" Mg Strip: $1.50
|+ Table 1: Materials and Costs
* Cu, Zn, Al, Ni Strip: $0.75/strip
!Material!!Unit!!Cost Per Unit
* Horizon wind-turbine: $5.00 each
|-
* Water turbine: $5.00 each
|style="text-align: center;"|Horizon Wind-Turbine||style="text-align: center;"|1||style="text-align: center;"|$7.50
* Solar battery panels: $10.00 each
|-
* Horizon hydrogen fuel cell: $12.00 each
|style="text-align: center;"|Solar Panel||style="text-align: center;"|1||style="text-align: center;"|$10.00
* 1 Farad 2.5V capacitor: $3.00 each
|-
* Alligator cable sets: $0.50/pair
|style="text-align: center;"|1 F 2.7 V Capacitor||style="text-align: center;"|1||style="text-align: center;"|$3.00
* Standard Lego car chassis plus Lego parts kit: $0, limit one per group
|-
* Lego to alligator cable clip connector: $0.10 each
|style="text-align: center;"|Alligator Clip Set||style="text-align: center;"|1 pair||style="text-align: center;"|$0.50
* Tape: $0.10/feet
|-
 
|style="text-align: center;"|LEGO Kit (Limit One Per Design)||style="text-align: center;"|1||style="text-align: center;"|$0.00
|-
|style="text-align: center;"|LEGO to Alligator Clip Connector||style="text-align: center;"|1||style="text-align: center;"|$0.10
|-
|style="text-align: center;"|Tape||style="text-align: center;"|1 foot||style="text-align: center;"|$0.10
|-
|}
=== Equipment Used ===
=== Equipment Used ===
* Horizon Wind-Turbine
* Horizon wind-turbine
* Sunforce 50013 1-Watt Solar Battery Charger
* Sunforce 50013 1 W solar battery charger
* Adjustable Table fan
* Adjustable table fan
* Heat Lamp
* Heat lamp
* DMM (Digital Multi-meter)
* 3 V power supply
* Music Voltmeter
* Digital multimeter
* 2V DC Motor
* Music voltmeter
* Horizon Hydrogen Fuel cell
* 9 V DC motor
* 1 Farad 2.5V Capacitor
* A 1 F 2.7 V capacitor
* Lemon Juice
* Three alligator clip sets
* Metal Strips
* Standard LEGO kit
** Magnesium, Nickel, Zinc, Copper, Aluminum
* Lego to alligator clip connector
* 3 Alligator cable sets  
* Scissors
* Standard Lego Car Chassis plus Lego parts kit  
* Lego to Alligator Cable Clip Connector
* Scissors  
* Tape
* Tape
<span style="color: red;">'''Warning'''</span> '''Magnesium is a highly reactive metal. Use carefully and only as described in these instructions.'''


== Procedure ==
= Procedure =
=== Part 1: Testing the Power Storage Devices ===
 
The power storage device and power sources will be tested individually. The results of the tests will be used in determining the best power source  for the sustainable energy vehicle.


==== Electrolytic/Citrus Cell ====
== 1. Testing the Power Storage Device ==
In this part of the experiment every team will receive a different set of metals to test and compare the different voltage outputs of the combinations.
During this part of the procedure, a capacitor will be charged and discharged with a music voltmeter. The current of the circuit with two capacitors, a music voltmeter, and a multimeter in series and in parallel will be measured.  
# Obtain two different samples of metals '''from your TA''' as well as one cup of lemon juice. TA's will select the different metal combinations for each team.
# Before inserting metal strips into the cup of lemon juice, clean the metal strips using the emery paper provided by the TA. Scrub the emery paper in one direction, then scrub perpendicular to the first direction. Once cleaned, insert the metals into the cup of lemon juice. '''Note:''' Magnesium reacts very fast, so if this is one of the metals given be sure to insert both strips at the same time and take readings immediately.
# Keep the metals on opposite sides of the cup to prevent them from touching.
# Connect one end of the first alligator cable set to one of the metal pieces and one end of the second alligator cable set to the other metal. These will be the electrodes of the cell.
# Connect the other ends of the alligator cable sets to the positive and negative ends of the digital multi-meter and measure the voltage. Record the value in units of volts. '''Note:''' If it is negative then the polarity is switched; switch the alligator clips to connect to the opposite sides of the DMM.
# The metal strip attached to the positive end of the digital multi-meter (red wire) is the anode (+) and the other (black wire) is the cathode (-).
# Record the values and present them to your TA. The TA will generate a spreadsheet with the voltage produced by each metal combination for all teams.
# Remove the electrodes to stop the chemical reaction. Wipe them clean with a paper towel. Discard the paper towel in the trash can.
<span style="color: red;">'''Warning'''</span> '''Magnesium left in lemon juice dissolves; remove from the cup immediately after this part of the experiment.'''


==== Hydrogen Fuel Cell ====
=== Charging a Capacitor ===
# Place the 2x4cm (small) length pieces of rubber tube into the bottom right pin on the hydrogen fuel cell (on both sides) and insert a cap (<span style="color: red;">'''red'''</span> for oxygen and '''black''' for hydrogen) into the other end of the tube.
# Insert the two longer tubes into the top left pin of the hydrogen fuel cell.
#: [[Image:Lab_renewener_13.png|thumb|400px|left|Figure 11: Hydrogen side of fuel cell]]<br style="clear: both;" />
# Take the two cylindrical beakers and place them on top of the stand provided locking it in place, then fill the two beakers with distilled water until the water level reaches zero.
#: [[Image:Lab_renewener_14.png|thumb|400px|left|Figure 12: Beakers filled with 30ml of distilled water]]<br style="clear: both;" />
# Place the two inner containers into the cylindrical beakers (make sure the side openings on the inner container is not blocked by the inner ring on the beakers), the distilled water from the beaker will fill out the inner container at this point.
#: [[Image:Lab_renewener_15.png|thumb|500px|left|Figure 13: The cylindrical beaker and inner container]]<br style="clear: both;" />
# Connect the two longer tubes to the inner container on each of the beakers corresponding to oxygen and hydrogen on the fuel cell. (Make sure there is no air in the inner containers.)
#: [[Image:Lab_renewener_17.png|thumb|400px|left|Figure 14: Oxygen tube inserted into the tip of the inner container]]<br style="clear: both;" />
# On the oxygen side of the fuel cell connect the syringe to the uncapped tube (first remove the <span style="color: red;">'''red'''</span> cap on the smaller tube). Fill the reversible fuel cell with distilled water using the syringe (by pulling '''out''' the air, not pushing in water) until all the air is removed from the long tube. Afterwards place the red cap on the smaller tube
#: [[Image:Lab_renewener_16.png|thumb|500px|left|Figure 15: Oxygen side of fuel cell with a syringe inserted to fill oxygen tubes side with distilled water]]<br style="clear: both;" />
#: '''IMPORTANT''': Make sure the connections of the wires to the fuel cell match (<span style="color: red;">'''red'''</span> to <span style="color: red;">'''red'''</span>, '''black''' to '''black''') otherwise it may lead to failure of this part of the experiment and damage to the fuel cell. If this problem occurs the students will have to take full responsibility for replacing the parts.
#: '''Hint: Place the longer tube above the oxygen beaker to hold the water coming out of the longer tube.'''
# Connect the 3V power supply to the positive and negative inputs on the fuel cell and turn on the power supply.
# Charge until H<sub>2</sub> inner container is filled with gas. The O<sub>2</sub> should be half because we're converting H<sub>2</sub>O and the stoichiometric coefficients demand that balance.
# Discharge the charged fuel cell by connecting it to the music voltmeter provided.
# Measure the voltage and current across the music voltmeter using the digital multimeter provided. The connections for measuring voltage and current across the music voltmeter are shown in Figures X & Y:
#: [[Image:Lab_renewener_19.png|thumb|500px|left|Figure X: Voltage measurement circuit]]<br style="clear: both;" />
#: [[Image:Lab_renewener_20.png|thumb|500px|left|Figure Y: Current measurement circuit.]]<br style="clear: both;" />
#: '''<span style="color: red">Note: </span> Be careful to not wire the multimeter in the voltage-reading configuration when reading current; accidentally doing this will cause the multimeter to blow its fuse and become inoperable.'''
# Calculate and record the power produced by the hydrogen fuel cell.
<!--* #: [[Image:Lab_renewener_18.png|thumb|500px|left|Figure 16: Mini Propeller and 3V power supply with extended cables]]<br style="clear: both;" /> -->
#: [[Image:HIR_1.png|thumb|500px|left|Figure 16: Music Voltmeter]]<br style="clear: both;" />


==== Charging a Capacitor ====
# The circuit in Figure 12 will be created to charge a capacitor. Connect an alligator clip to each of the cables coming out of the 3 V power supply. Red is positive and black is negative.[[Image:Circuit_to_Charge_a_Capacitor_.jpeg|thumb|500px|center|Figure 12: Circuit to Charge a Capacitor]]
# Connect an alligator clip to each of the cables coming out of the 3V power supply. (<span style="color: red;">'''red'''</span> is positive and '''black''' is negative)
# Connect one of the unconnected alligator clips to one of the leads of the ammeter (the multimeter set to measuring current).
# Connect to the one of unconnected alligator clips the ammeter (multimeter setting measuring current)  
# Connect the rest of the unconnected cables (one from the ammeter and one alligator clip) in series to the leads of the capacitor with the polarity indicated.
# Connect the rest of the unconnected cables (one from ammeter and one alligator clip) connect to pins of the capacitor with correspond polarity. (refer to Figure 10)
# Charge the capacitor until the current in the circuit is 0 A.
# Charge until the current is zero.  
# Discharge the charged capacitor by connecting it to the music voltmeter. The capacitor is discharging when the music voltmeter audibly plays a song.
# Discharge the charged capacitor by connecting it to the music voltmeter provided.
[[Image:Lab_renewener_11.png|thumb|500px|center|Figure 17: This is circuitry for charging a capacitor.]]<br style="clear: both;" />


=== Part 2: Testing the Power Sources ===
=== Capacitors in Series and Parallel ===
Each team will analyze '''one''' type of renewable power source, determined by the TA. Both voltage and current must be measured and recorded, and power must be calculated.
# Charge two capacitors with the method used to charge one capacitor.
# Wire the two capacitors, the music voltmeter, and the multimeter in series.
## Refer to the schematic presented earlier to wire a circuit in series.
## Remember to check for the proper polarity, otherwise the circuit will not run.
# Record the current produced by the circuit in series.
# Repeat steps 1-2, but wiring the circuit in parallel. Instead of recording the current, record the voltage produced by the circuit


==== Wind turbine ====
== 2. Testing the Power Sources ==
# Connect the wind turbine to the music voltmeter using the alligator clips provided. Measure the voltage and current across the music voltmeter using the digital multimeter provided. The connections for measuring voltage and current across the music voltmeter are shown in Figures 9 & 10.
# Adjust the position of the turbine to find the maximum voltage and current that can be generated.
# Calculate and record the power generated by the turbine and give information to TA.


==== Solar Panel ====
One type of renewable power source will be assigned and analyzed as determined by the TA. Using the digital multimeter, both voltage and current must be measured and recorded, and power must be calculated.
# Connect the solar panel to the music voltmeter using the alligator clips provided. Place the solar panel near the heat lamp and measure the voltage and current across the music voltmeter using the digital multimeter provided.
# Adjust the position of the solar panel to find the maximum voltage and current that can be generated.
# Calculate and record the power generated by the solar panel and give information to the TA.
#: '''<span style="color: red">Caution!</span> The heat lamps and solar panels may become extremely hot when used for a long duration of time. Do not touch them immediately after use and turn them off when not in use.'''


==== Water Turbine ====
=== Wind Turbine ===
# Connect the leads of the hydroelectric turbine to the music voltmeter using the alligator clips provided.
# Connect the wind turbine to the music voltmeter using the alligator clips following the schematic presented earlier. Measure the voltage and current across the music voltmeter using the digital multimeter.  
# Ask a TA to open the spigot on the bucket at the top of the workbench.
# Adjust the position of the turbine blades near the fan to find the highest voltage and current that can be generated.
# Calculate and record the power generated by the solar panel and give information to the TA.
# Calculate and record the power generated by the turbine and give the information to a TA.


==== Hydroelectric Turbine ====
[[File: Measure_Voltage_of_Wind_Turbine.png|400px|thumb|center|Figure 13: Circuit to Measure Voltage of the Wind Turbine]]
# Connect the red wire of the water wheel to the positive (red) end of the multimeter and the black wire to the negative (black) end of the multimeter. Set the multimeter to measure voltage.
# Notify the TA once the connections have been set up. The TA will then take you to the AUV room's sink to measure the voltage and (electrical) current produced by the water coming from the sink. '''<span style="color: red">Be very careful to keep water off of the multimeters.</span>'''
# Calculate and record the power generated by the water wheel and give information to the TA.


[[File: Measure_Current_of_Wind_Turbine.png|400px|thumb|center|Figure 14: Circuit to Measure Circuit of the Wind Turbine]]


=== Part 3: Renewable Car Competition ===
=== Solar Panel ===
# Assess your materials and consider the data established from Part 1 and Part 2. Choose materials for your car design, keeping in mind the Competition Ratio. Make sure you make preliminary sketches during this process. (You may choose different combinations of power sources and power storage devices for your design)
# Your design must be able to hold the power storage devices on top of it during the trials (you may modify your design to fit the power storage devices as you deem fit). Prepare a price-list for your renewable energy powered vehicle based on the setups and materials you have chosen. Have your TA '''sign''' the sketches and the price-list.
# Your TA will provide the materials needed for your design. If you decide to modify your design during the construction of your car, note the changes and describe the reasons for them. If the modifications required more materials to be used, make sure you update your price list and your TA approves it. (Note: You may modify your design between trials)
'''Before entering the competition, test if both your motor and cable are working.'''


==== Competition ====
# Connect the solar panel to the music voltmeter using the alligator clips. Place the solar panel near the heat lamp and measure the voltage and current across the music voltmeter using the digital multimeter.
The renewable energy vehicle must be able to carry the power storage device you choose to use on it (e.g. fuel cell, capacitor). You may only power your capacitor and fuel cell using the power sources provided, violations to these rules will result in a failing grade for the lab report for this lab.
# Adjust the position of the solar panel to find the highest voltage and current that can be generated.
# Calculate and record the power generated by the solar panel and give the information to a TA.


When requested by the TA, the student will position the renewable energy car and complete the necessary connections before the trial begins.
[[File: Measure_Voltage_of_Solar_Panel.png|400px|thumb|center|Figure 15: Circuit to Measure Voltage of the Solar Panel]]


The competition will be won by the team that has the highest competition ratio:
[[File: Measure_Current_of_Solar_Panel.png|400px|thumb|center|Figure 16: Circuit to Measure Current of the Solar Panel]]
 
=== Data Analysis ===
 
# The TA will display the power data from each renewable energy source on the board. Based on the power output of each renewable energy source and the analysis of the circuits in series and parallel, determine the best power source and circuit design to power a sustainable energy vehicle with two capacitors. 
 
'''<span style="color: red">Caution! The heat lamps and solar panels may become extremely hot when used for a long duration of time. Do not touch them immediately after use and turn them off when not in use.'''</span>
 
== Competition Rules ==
 
The competition rules must be followed at all times during the competition. Violation of any of these rules will result in the disqualification of the design.
 
* The renewable energy vehicle must carry its power storage device (e.g. capacitor)
* The capacitors can only be charged for one minute using the provided power sources
* Each design will only be allowed one trial
* Do not touch the leads of the charged capacitor, this will discharge the capacitor
* Do not connect the power storage device until immediately before the trial is run
* The trial will end once the vehicle stops moving for a maximum of 5 min
* The design with the highest competition ratio (CR) wins (5)
   
   
<math>CR = \frac{distance\left[\text{ft}\right]}{1\left[\text{s}\right] + time\left[\text{s}\right]} \times \frac{100}{Cost\left[$\right]} + distance\left[\text{ft}\right]\,</math>
<center><math>CR = \frac{Distance\left[\text{ft}\right]}{1\left[\text{s}\right] + Time\left[\text{s}\right]} \times \frac{100}{Cost\left[$\right]} + Distance\left[\text{ft}\right]\,</math></center>
<p style="text-align:right">(5)</p>
 
In (5), distance, time, and cost are measured in feet, seconds, and US dollars respectively.
 
=== 3. Sustainable Energy Vehicle Competition ===


The TA will record the test data after five minutes or when the car stops moving, whichever occurs first. The TA will then calculate the competition ratio. The tabulation for the whole class will be provided.
# Assess the materials provided and consider the data from testing the power storage device and testing the power sources. Keep in mind the variables of the competition ratio while choosing materials for the vehicle design. Make preliminary sketches during this process.
# A minimum of 2 capacitors must be used in the design. The vehicle must carry the power storage device during the trial. While modifying the design, keep in mind the space needed to fit the power storage device (capacitor) and its wires. Prepare a cost list of the materials used in the design and specify the total price. A TA must approve the sketches and the cost list.
# A TA will provide the materials needed for the design. If the design is modified during the construction, note the changes and explain the reasons for them. If the modifications require more materials to be used, update the cost list and have a TA approve it.
# With the chosen power source, charge the two capacitors for 1 min each.
# Construct the vehicle based on the sketched design.
# Before entering the competition, make sure the motors turn in the desired direction of travel.
# Run the trial.
# Give the total cost of the design to a TA. The TA will provide the resulting competition ratio.


== Assignment ==
= Assignment =
=== Individual Lab Report ===
== Team Lab Report ==
Follow the lab report guidelines laid out in the page called [[Specifications for Writing Your Lab Reports]] in the Technical Communication section of this manual. As you write, the following discussion points should be addressed in the appropriate section of your lab report:
<!--<b>Note:</b> You will be writing a team lab report rather than an individual one. See the [[Team Authoring Strategies]] page in the <i>Technical Communication</i> of this online manual for guidance of how to do this.-->
* Describe the rules of the competition in your introduction. What consequences did the rules have for your design decisions? Use the appropriate equations in your answer.
* Describe an electrolytic cell in your introduction. What consequences did the electrode voltages have for your design decisions?
* Explain how solar panels and wind turbines work.
* Explain the concepts of the hydrogen fuel cell and capacitors.
* Discuss the advantages and disadvantages of the solar panel and wind-turbine..
* Discuss the advantages and disadvantages of hydrogen fuel cell compared to other storage devices (e.g. capacitors or batteries)
* Describe your renewable energy vehicle design and explain the choices you made in your design.
* Discuss minimal design. Did you use all the materials you purchased? Describe the importance of minimal design and explain how you employed it in your design. (how did you minimize your cost)
* Describe how your design succeeded or failed. What choices could you have made to improve your final standing in the competition?
* Discuss how you would improve the competition ratio, how was your design compared to the other group’s designs.
* Describe the power source chosen for the design.
* Include spreadsheet with every team's results. Describe the results and talk about other designs in the class.


{{Lab notes}}
<!--This lab report is <b>optional</b> and you will receive <b>extra credit</b> for submitting it.-->


=== Team PowerPoint Presentation ===
{{Labs:Lab Report}}
Follow the presentation guidelines laid out in the [[EG1003 Lab Presentation Format]] section of this manual. When you are preparing your presentation, consider the following points:
* Since one term in the competition ratio is cost, present the cost of your vehicle. Use the page [[How to Show Cost Data in Presentations]] for instructions on how to do this.
* How would you improve your renewable energy powered car?


== References ==
* Describe the rules, ratio, and design strategy of the competition in the introduction. What consequences did the rules and ratio have for any design decisions?
[1] NextEra Energy Resources, LLC., . "Benefits of Renewable Energy." NextEra Energy Resources. NextEra Energy Resources, 2012. Web. 24 Jul 2012. <http://www.nexteraenergyresources.com/content/environment/benefits.shtml>.
* Explain how solar panels and wind turbines work
* Discuss capacitors
* Discuss the advantages and disadvantages of the solar panel and wind turbine
* Describe the renewable energy vehicle design and explain the choices made in the design
* Discuss the power sources and their power output. How did the voltage measurements of the power sources impact the design?
* Discuss minimal design. Were all the materials purchased used? Describe the importance of minimal design and explain how it was employed in the design. Did the design minimize cost?
* Describe how the design succeeded or failed. What choices would improve the design’s standing in the competition?
* Discuss how the competition ratio can be increased, and how the design compared to the other designs
* Specify the power source chosen for the design
* Include the spreadsheet with every design's results. Describe the results and talk about other designs in the class


[2] Locke, S.. "How does solar power work." Scientific american. Scientific American, 2008. Web. 24 Jul 2012. <http://www.scientificamerican.com/article.cfm?id=how-does-solar-power-work>.
{{Labs:Lab Notes}}
 
[3] Layton, J.. "How Wind Power Works." How stuff works. Discovery, 2011. Web. 24 Jul 2012. <http://science.howstuffworks.com/environmental/green-science/wind-power.htm>.
== Team PowerPoint Presentation ==
 
{{Labs:Team Presentation}}
 
* Since one term in the competition ratio is cost, present the cost of the vehicle. Use the page [[How to Show Cost Data in Presentations]] for instructions on how to do this
* How would the renewable energy vehicle be improved?
 
= References =
 
Layton, J.. "How Wind Power Works." How stuff works. Discovery, 2011. Retrieved 24 July 2012. <http://science.howstuffworks.com/environmental/green-science/wind-power.htm>.
 
Locke, S.. "How Does Solar Power Work." Scientific American. Scientific American, 2008. Retrieved 24 July 2012. <http://www.scientificamerican.com/article.cfm?id=how-does-solar-power-work>.
 
NextEra Energy Resources, LLC. "Benefits of Renewable Energy." NextEra Energy Resources. NextEra Energy Resources, 2012. Retrieved 24 July 2012. <http://www.nexteraenergyresources.com/content/environment/benefits.shtml>.


[4] Reg Tyler, . "Types of Fuel Cells." Energy efficeny and renewable energy. U.S. Department of Energy, 2011. Web. 24 Jul 2012. <http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html>.
Reg Tyler, . "Types of Fuel Cells." Energy efficiency and renewable energy. U.S. Department of Energy, 2011. Retrieved 24 July 2012. <http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html>.


[5] Perlman, Howard.. "Hydroelectric power: How it works." U.S. Geological Survey, 2016. Web 4 Jan 2018. <https://water.usgs.gov/edu/hyhowworks.html>.
{{Laboratory Experiments}}

Latest revision as of 03:01, 21 August 2022

Objective

The experimental objective of this lab is to evaluate different sources of renewable energy and use the results of that evaluation to design a vehicle that is powered by a renewable energy source or a capacitor that is charged by a renewable energy source. The design will be entered in a competition that is judged by a ratio that uses distance traveled, travel time, and cost. The highest ratio wins.

Overview

From sails to power boats, windmills to pump water, or water-driven wheels to power machinery that mills grains, humans have been using renewable energy sources for millennia. A significant amount of our energy production comes from non-renewable resources, such as oil, natural gas, and coal. The detrimental effects on public health and the environment from burning fossil fuels have prompted greater interest and investment in renewable energy sources, including solar, wind, and hydroelectric power though hydroelectric power is not considered in this lab. Scientists and engineers must address concerns about the inability of some renewable sources, notably solar power and wind power, to generate power consistently so there is equal interest in developing energy storage devices that can operate at grid-scale or hold sufficient energy to power entire communities for an extended time after being charged by a renewable energy source.

Types of Renewable Energy

Renewable energy is a type of energy that can be harnessed from naturally replenished resources. Some examples of this are sunlight, wind, and water. There are many benefits to using renewable energy. They are clean energy sources, and they come from abundant sources that do not become depleted. If these renewable resources can be harnessed effectively, they can solve the problems with using non-renewable energy sources (NextEra Energy Resources, 2012). In the last few years, renewable energy has been the fastest-growing energy source globally (International Energy Agency, 2021). In this lab, solar and wind energy will be used.

Solar Power

Sunlight, like any other type of electromagnetic radiation, contains energy. Typically, when sunlight hits an object, the energy that it contains is converted into heat. Certain materials can absorb and convert that energy into an electrical current. In this form, sunlight can be used as a power source or stored for later use.

Solar panels are devices that generate electrical current from sunlight. The panels contain a crystalline material that absorbs and converts the sunlight into electricity. The crystalline material has a repeating structure formed by a network of covalent bonds where electrons are shared by atoms within the crystal. Traditional solar cells are made from crystalline silicon.

To produce a current, there must be a difference in the concentration of electrons between one area and another to cause their flow. In a silicon solar cell, a concentration difference is created using two types of silicon, p-type and n-type. The p-type silicon is created by adding atoms, such as boron, that have one fewer electron in their valence energy level than silicon has. As a result, a vacancy of electrons, or a hole, forms. The n-type silicon is created by adding atoms that have one more electron in their valence energy level than silicon has so that there is an excess of electrons that can move around the crystal structure and create an electrical current. In a solar cell, p-type and n-type silicon are sandwiched together to create a p-n junction, as shown in Figure 1 (Locke, 2008). The p-type area is positively charged, and the n-type area is negatively charged.

When sunlight hits the silicon on the solar panel, the photons from the sunlight energize the electrons in the material. The electrons within the crystal move to a higher energy level, creating holes. If the p-type and n-type silicon are connected with a wire, the electrons will flow from the n-type layer to the p-type layer, and electrical current is generated.

Figure 1: A Silicon Solar Panel Showing the Electron Flow

Other materials have been used in the production of solar panels. Panels made from copper indium gallium (di)selenide (CIGS) have a smaller crystalline structure and are less expensive than silicon. CIGS panels are relatively flexible and can easily be shaped into flexible films. The use of CIGS to make solar panels is referred to as thin-film solar technology because of its flexible nature. CIGS panels are not as good at converting absorbed light into electrical current compared to silicon, but for mass production purposes, CIGS solar panels are the more cost effective approach to produce solar panels for frequent use (Locke, 2008). In the last decade, perovskite materials have also received attention for thin film technologies because of their competitive efficiency (Dey et al., 2021).

Wind Energy

Wind turbines are used to capture the wind’s energy and convert it into electrical energy. The blades on wind turbines are slanted so that as the wind passes over the blades, it creates an uneven pressure on each side, causing them to rotate. The spinning blades drive a low speed shaft connected to a gearbox. The gearbox converts the low speed rotation to a high speed rotation through a high speed shaft. The high speed shaft is connected to a brake and then into an electrical generator where mechanical energy is converted to electrical energy (Layton, 2011).

A basic electrical generator is made of permanent magnets on each side with a rectangular coil connected to a commutator, which is a rotary electrical switch (Figure 2). The two permanent magnets on each side create a magnetic field. As the rectangular coil spins mechanically, the magnetic field through the area of the coil changes, creating an alternating current through the coil. The commutator switches the polarity of the coil just as the polarity of the alternating current changes, creating a direct current. The current is then output from the wind turbine (Layton, 2011).

Figure 2: The Internal Structure of an Electrical Generator (Layton, 2011)


Energy Storage

Capacitors have many uses in circuits and signal processing. A capacitor is an electrical device that is used to store charge temporarily. Some capacitors can be used in place of a battery, but they operate very differently from a battery. A capacitor is charged by a voltage source logarithmically, as shown in Figure 3. In this lab, a capacitor will be used as the power source for the renewable energy vehicle.

Figure 3: Capacitor Charging Curve

Because of their design, capacitors are sensitive to the polarity of the voltage applied to them. The capacitors used in this lab must be connected with the proper polarity. In the lab, the capacitor’s negative lead must be connected to the negative applied voltage (Figure 4). Failure to do this will cause the capacitor to fail.

Figure 4: Polarized Capacitor

The energy a capacitor holds is proportional to the square of the voltage across the capacitor (1).

(1)

In (1), E is the energy, C is the capacitance, and V is the voltage.

Electrical Components

The design of a circuit determines its behavior. In this lab, one circuit design will increase the speed output of a motor and the other will increase the torque output of a motor. In electrical engineering, different electrical components are represented by different symbols. Figures 5 show the symbols for a battery, DC source, and capacitor. They are all forms of energy storage devices.

Figure 5: (l-r) Symbol for Capacitor, DC Source, Battery

Different arrangements of electrical components allow engineers to design different devices. Components, such as resistors, inductors, and capacitors, can be arranged in two different ways. In a series circuit, the element's components are connected end to end. The current in a series circuit remains the same in all the electrical elements (Figure 6).

Figure 6: A Series Circuit

In a series circuit, as shown in Figure 6, the sum of the voltages across each element is equal to the voltage of the power source (2). Note that there is a singular path for current to flow through.

(2)

In (2), Vout is the voltage output and VA, VB, and VC represent the voltage of the individual components.

In a parallel circuit, as shown in Figure 7, the circuit's components are connected at opposing ends. The current that is supplied by the voltage source equals the current that flows through elements D and E.

Figure 7: A Parallel Circuit

The voltage across the elements that are parallel is the same (3). In comparison to a series circuit, a parallel circuit has multiple paths for the current to flow.

(3)

In (3), Vout is the voltage output and VD and VE represent the voltage of the individual components.

A digital multimeter will be used in this lab to read the current and voltage across components in circuits. Please read the Digital Multimeters Guidelines before performing this lab in order to understand how to properly operate a digital multimeter. Digital multimeters can measure either voltage or current, indicated by the symbols shown in the circuit diagram (Figure 8).

Figure 8: (l-r) Symbols for a Voltmeter and Ammeter

Depending on whether voltage or current is being measured in a circuit, the multimeter will be arranged in the circuit in a different manner. To measure the voltage across an electrical component, the multimeter must be placed in the circuit in parallel (Figure 9).

Figure 9: Multimeter in Parallel

To measure the current across an electrical component, the multimeter must be placed in the circuit in series (Figure 10). As described in the Digital Multimeters Guidelines, ensure the leads are connected to the appropriate multimeter ports depending on which value is being measured.

Figure 10: Multimeter in Series

After measuring the voltage and current across a component in a circuit, the electrical power output of that component can be calculated using the Power Law (4).

(4)

In (4), P is the power (Watts), I is the current (Amperes), and V is the voltage (Volts).

The motor provided in the lab is a 9 DC motor that will operate with voltages no more than 9 V with reduced torque and speed (Figure 11). A motor with no load operates under the current of 9 mA, and a stalled motor operates under the current of over 350 mA. Increasing the voltage provided to the motor increases the speed. Increasing the current, increases the torque.

Figure 11: LEGO 9V Motor

Design Considerations

  • Which source yields the most voltage per unit cost?
  • Which circuit configuration will provide the most voltage across the load? Parallel or series?
  • Which aspects of the competition formula are most advantageous?

Materials and Equipment

Materials with Price List

Table 1: Materials and Costs
Material Unit Cost Per Unit
Horizon Wind-Turbine 1 $7.50
Solar Panel 1 $10.00
1 F 2.7 V Capacitor 1 $3.00
Alligator Clip Set 1 pair $0.50
LEGO Kit (Limit One Per Design) 1 $0.00
LEGO to Alligator Clip Connector 1 $0.10
Tape 1 foot $0.10

Equipment Used

  • Horizon wind-turbine
  • Sunforce 50013 1 W solar battery charger
  • Adjustable table fan
  • Heat lamp
  • 3 V power supply
  • Digital multimeter
  • Music voltmeter
  • 9 V DC motor
  • A 1 F 2.7 V capacitor
  • Three alligator clip sets
  • Standard LEGO kit
  • Lego to alligator clip connector
  • Scissors
  • Tape

Procedure

The power storage device and power sources will be tested individually. The results of the tests will be used in determining the best power source for the sustainable energy vehicle.

1. Testing the Power Storage Device

During this part of the procedure, a capacitor will be charged and discharged with a music voltmeter. The current of the circuit with two capacitors, a music voltmeter, and a multimeter in series and in parallel will be measured.

Charging a Capacitor

  1. The circuit in Figure 12 will be created to charge a capacitor. Connect an alligator clip to each of the cables coming out of the 3 V power supply. Red is positive and black is negative.
    Figure 12: Circuit to Charge a Capacitor
  2. Connect one of the unconnected alligator clips to one of the leads of the ammeter (the multimeter set to measuring current).
  3. Connect the rest of the unconnected cables (one from the ammeter and one alligator clip) in series to the leads of the capacitor with the polarity indicated.
  4. Charge the capacitor until the current in the circuit is 0 A.
  5. Discharge the charged capacitor by connecting it to the music voltmeter. The capacitor is discharging when the music voltmeter audibly plays a song.

Capacitors in Series and Parallel

  1. Charge two capacitors with the method used to charge one capacitor.
  2. Wire the two capacitors, the music voltmeter, and the multimeter in series.
    1. Refer to the schematic presented earlier to wire a circuit in series.
    2. Remember to check for the proper polarity, otherwise the circuit will not run.
  3. Record the current produced by the circuit in series.
  4. Repeat steps 1-2, but wiring the circuit in parallel. Instead of recording the current, record the voltage produced by the circuit

2. Testing the Power Sources

One type of renewable power source will be assigned and analyzed as determined by the TA. Using the digital multimeter, both voltage and current must be measured and recorded, and power must be calculated.

Wind Turbine

  1. Connect the wind turbine to the music voltmeter using the alligator clips following the schematic presented earlier. Measure the voltage and current across the music voltmeter using the digital multimeter.
  2. Adjust the position of the turbine blades near the fan to find the highest voltage and current that can be generated.
  3. Calculate and record the power generated by the turbine and give the information to a TA.
Figure 13: Circuit to Measure Voltage of the Wind Turbine
Figure 14: Circuit to Measure Circuit of the Wind Turbine

Solar Panel

  1. Connect the solar panel to the music voltmeter using the alligator clips. Place the solar panel near the heat lamp and measure the voltage and current across the music voltmeter using the digital multimeter.
  2. Adjust the position of the solar panel to find the highest voltage and current that can be generated.
  3. Calculate and record the power generated by the solar panel and give the information to a TA.
Figure 15: Circuit to Measure Voltage of the Solar Panel
Figure 16: Circuit to Measure Current of the Solar Panel

Data Analysis

  1. The TA will display the power data from each renewable energy source on the board. Based on the power output of each renewable energy source and the analysis of the circuits in series and parallel, determine the best power source and circuit design to power a sustainable energy vehicle with two capacitors.

Caution! The heat lamps and solar panels may become extremely hot when used for a long duration of time. Do not touch them immediately after use and turn them off when not in use.

Competition Rules

The competition rules must be followed at all times during the competition. Violation of any of these rules will result in the disqualification of the design.

  • The renewable energy vehicle must carry its power storage device (e.g. capacitor)
  • The capacitors can only be charged for one minute using the provided power sources
  • Each design will only be allowed one trial
  • Do not touch the leads of the charged capacitor, this will discharge the capacitor
  • Do not connect the power storage device until immediately before the trial is run
  • The trial will end once the vehicle stops moving for a maximum of 5 min
  • The design with the highest competition ratio (CR) wins (5)

(5)

In (5), distance, time, and cost are measured in feet, seconds, and US dollars respectively.

3. Sustainable Energy Vehicle Competition

  1. Assess the materials provided and consider the data from testing the power storage device and testing the power sources. Keep in mind the variables of the competition ratio while choosing materials for the vehicle design. Make preliminary sketches during this process.
  2. A minimum of 2 capacitors must be used in the design. The vehicle must carry the power storage device during the trial. While modifying the design, keep in mind the space needed to fit the power storage device (capacitor) and its wires. Prepare a cost list of the materials used in the design and specify the total price. A TA must approve the sketches and the cost list.
  3. A TA will provide the materials needed for the design. If the design is modified during the construction, note the changes and explain the reasons for them. If the modifications require more materials to be used, update the cost list and have a TA approve it.
  4. With the chosen power source, charge the two capacitors for 1 min each.
  5. Construct the vehicle based on the sketched design.
  6. Before entering the competition, make sure the motors turn in the desired direction of travel.
  7. Run the trial.
  8. Give the total cost of the design to a TA. The TA will provide the resulting competition ratio.

Assignment

Team Lab Report

Follow the lab report guidelines laid out in the EG1004 Writing Style Guide in the Technical Writing section of the manual. The following points should be addressed in the appropriate section of the lab report.

  • Describe the rules, ratio, and design strategy of the competition in the introduction. What consequences did the rules and ratio have for any design decisions?
  • Explain how solar panels and wind turbines work
  • Discuss capacitors
  • Discuss the advantages and disadvantages of the solar panel and wind turbine
  • Describe the renewable energy vehicle design and explain the choices made in the design
  • Discuss the power sources and their power output. How did the voltage measurements of the power sources impact the design?
  • Discuss minimal design. Were all the materials purchased used? Describe the importance of minimal design and explain how it was employed in the design. Did the design minimize cost?
  • Describe how the design succeeded or failed. What choices would improve the design’s standing in the competition?
  • Discuss how the competition ratio can be increased, and how the design compared to the other designs
  • Specify the power source chosen for the design
  • Include the spreadsheet with every design's results. Describe the results and talk about other designs in the class

Remember: Lab notes must be taken. Experimental details are easily forgotten unless written down. EG1004 Lab Notes paper can be downloaded and printed from the EG1004 Website. Use the lab notes to write the Procedure section of the lab report. At the end of each lab, a TA will scan the lab notes and upload them to the Lab Documents section of the EG1004 Website. One point of extra credit is awarded if the lab notes are attached at the end of the lab report. Keeping careful notes is an essential component of all scientific practice.

Team PowerPoint Presentation

Follow the presentation guidelines laid out in the EG1004 Lab Presentation Format in the Technical Presentations section of the manual. When preparing the presentation, consider the following points.

  • Since one term in the competition ratio is cost, present the cost of the vehicle. Use the page How to Show Cost Data in Presentations for instructions on how to do this
  • How would the renewable energy vehicle be improved?

References

Layton, J.. "How Wind Power Works." How stuff works. Discovery, 2011. Retrieved 24 July 2012. <http://science.howstuffworks.com/environmental/green-science/wind-power.htm>.

Locke, S.. "How Does Solar Power Work." Scientific American. Scientific American, 2008. Retrieved 24 July 2012. <http://www.scientificamerican.com/article.cfm?id=how-does-solar-power-work>.

NextEra Energy Resources, LLC. "Benefits of Renewable Energy." NextEra Energy Resources. NextEra Energy Resources, 2012. Retrieved 24 July 2012. <http://www.nexteraenergyresources.com/content/environment/benefits.shtml>.

Reg Tyler, . "Types of Fuel Cells." Energy efficiency and renewable energy. U.S. Department of Energy, 2011. Retrieved 24 July 2012. <http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html>.