Introduction of Renewable Energy to High School Students in a Summer Camp: Hands-on Experimental Approach

The hands on approach used to introduce the principles of renewable energy resources to high school students are presented in this paper. This approach was implemented for the eleven students who attended the STEM summer camp at West Virginia University Institute of Technology (WVU Tech) in summer 2015. The course was designed to include from the basic concepts of electricity to wind and solar energy as well as energy storage. First, the students were able to measure the grid power characteristics using an Electricity Usage Monitor. Then, they learned how to measure voltage and current using multi-meters. Next, they were introduced to the idea of renewable energy using the Alternative Energy Conversion Kit. After these preliminary steps, the students started to conduct experimentations of solar photovoltaic cells, solar thermal energy devices, wind turbines, and fuel cells. Through these experiments the students discovered (not lectured) the principles of operations of these units, the effects of various parameters on their performance, and their pros and cons. The students’ performance on the pre-and post-quizzes showed a significant improvement in students understanding. Their feedback also indicated that while they learned a lot, they had a fun time and enjoyed the course. Introduction The introduction of renewable energy to the students while they are in the high school level or even earlier is becoming popular. The department of Energy and National Renewable Energy Laboratory (NREL) [1, 2], Illinois Valley Community College [3], the Union of Concerned Scientists [4], and others [5, 6] have published guidelines and booklets for this purpose. This paper presents the hands on approach to educate the high school students who attended the STEM summer camp at West Virginia University Institute of Technology (WVU Tech) about the concepts of energy in general and renewable energy resources in particular. The idea of the program is to expose what engineers do and how they try to solve problems that the world is facing now. Compare to other programs with similar nature, this program is unique in its purely hands on approach. In this approach the level of lecturing is minimized and the students discover the principles behind each system themselves. Although the effectiveness of this approach has not been compared to other approaches, the growing interest in the program each year and the increase of enrolment indicate the relative success of the program (at least qualitatively if not quantitatively!). There were eleven students from 9 th to 11 th grades in the class. The majority of them were female. As expected from students who decided to attend the STEM summer camp, their most favorite subjects were math and science. Forming the teams In order to motivate students, they were divided into two groups. The students were informed that there would be a competition between two teams. Each activity had a certain score. Table 1 was used to track the scores by the instructor and the students in each team. Table 1: The score-sheet for the competition between two teams Experiment Max Score Score Team A Score Team B Electricity Usage Monitor 5 Voltage and current measurements 10 Alternative Energy Conversion Kit 10 Solar photovoltaic cell experiments 15 Solar car race 10 Solar flash light 10 Solar thermal energy 10 Wind turbines 20 Fuel cells 10 Total 100 In the forming of the groups, the most important factor was diversity of team members. The students were not allowed to choose their teammates. At beginning of the class, each student was asked to write her/his high school name, grade level, and GPA on a piece of paper. To maintain confidentiality and avoid discomfort of students with low GPA, answering the question regarding the student GPAs was optional. This information was used to mix and match students to form the “almost equal” teams with maximum diversity in each team. Also, the gender balance in each team was taken into account. Beside the diversity of the teams, the objective of this practice was to help students to develop their ability to work in a team with team members that they were not already familiar with. After the students wrote their information, the students took a pre-test related to the topic. While they were taking the test, the instructor formed the teams. Each team sat around a dedicated table. At this point they could start their experiments. Each team was given an experiment to conduct and asked to prepare a brief report about it. For each experiment, all team members should discuss and one student should be in charge of writing the summary of the observation and the conclusion of the discussion. Then, the responsible student from each team should present the report of the experiment to the whole class as the representative of the team. For each experiment, a different student represented the team. In this practice, everyone in the team was engaged and developed the skill for technical writing and oral presentation of a scientific observation. For experiments in which there existed two sets of instruments, the teams conducted experiments simultaneously. For others with a single instrument, two different experiments were conducted by teams simultaneously. After teams were done with each experiment, they switched the instrumentations. These experiments are presented in the rest of this paper. Figure 1 illustrates the equipment used in these experiments. The program started with an experimentation using an Electricity Usage Monitor. Figure 1: Equipment used in experiments Experimentation using an Electricity Usage Monitor In this experiment, the students used an Electricity Usage Monitor (Kill-A-Watt, about $30 each, Figure 2) to get familiar with the specifications of electricity in the US and the determination of power consumption and its cost. The students measured the voltage and frequency of the electricity from grid, current, the power consumption of the appliances connected to the unit, the power factor, the energy consumption, and the duration of the measurement. In order to conduct the experiments, two appliances (a fan and a heater) were connected to the meter and the values of the parameters recorded. Then, they were asked to disconnect one and then both consumers and observe that the voltage did not change and it is independent of the load. Later, when the students were conducting experiments with batteries, they reminded with the fact that unlike electricity from the grid, the voltage of electricity from batteries varies with the load. Finally, the appliances were reconnected and left to operate for a period of time and then the electrical energy consumption was recorded. During these measurements the students were reminded of the importance of recording units of measurement for each parameter. Also, the fluctuation of the parameters and the inaccuracy of instruments were discussed. Then, the concept of energy, power, voltage, current, frequency, AC and DC electricity, apparent power, real power, power factor, and electrical energy consumption along with appropriate equations were explained. The students used these equations to verify their readings from the meter. Finally, to conclude this part of the class, the students used an actual electricity bill to determine the cost of electricity per unit of energy (kW.hr). They used this value to estimate the cost of running two appliances for the measured period of time. Figure 2: Electricity Usage Monitor (Kill-A-Watt) In the next step, the students were trained in using multi-meters to measure voltage and current. Voltage and current measurement using multi-meters A quick discussion with the students revealed that they were not familiar with the utilization of multi-meters. So in this part, the students developed the skills to setup electrical circuits and to measure voltage and current. Each team was given a battery pack, a variable resistance, and two multi-meters. First, they connected the load (variable resistance) to the power supply (batteries). Then, they were instructed to connect one multi-meter to the load in parallel to measure voltage and connect the other in series to measure current (Figure 3). Finally, they connected both multimeters to measure both voltage and current simultaneously. They varied the resistance and observed the effects on voltage and current. They realized that in this case, unlike electricity from the grid, voltage was affected by the load. This experiment was a challenging one and the students had a relatively difficult time to make sense of the arrangement. In the next experiment, the students used a commercially available Alternative Energy Conversion Kit to conduct experiments on renewable energy sources. Figure 3: Voltage and current measurement using multi-meters Alternative Energy Conversion Kit This inexpensive kit (cost less than $70) is composed of various sources of electricity generation units. It also has several equipment as electricity consumers where electrical energy is converted to various forms of energy i.e. mechanical, chemical, light, and sound energy (Figure 4). The electrical energy suppliers were: 1. Batteries (conversion of chemical energy to electrical energy) 2. Solar cell (conversion of light energy to electrical energy) 3. Hand generator (conversion of mechanical energy to electrical energy) 4. Wind turbine (conversion of kinetic energy of air flow to electrical energy) In each case, the students measured the open circuit voltage (OCV) of the generators by a multimeter to get some idea about how much power each can produce (Figure 5). Since they were familiar with batteries, they started with them to have a bench mark to compare OCV of other electricity generators. For the solar cell, they observed the effect of distance to the source of light (a study-light) on the measured OCV. For the hand generator, they observe that the faster the cranking of the handle, the higher the OCV