1.    What is a statement that summarizes the “macro” version of your problem? What is a statement that summarizes the “micro” version of your problem? In both cases think of an “elevator pitch” version of your problem statements.

Macro: The world needs solar panels to be more efficient in order to keep up with the rise in energy demand while also replacing fossil fuels with renewables as the main source of energy.

Background Information: Even though humans have been using solar energy for thousands of years and eventually learned to make electricity from it, the U.S. Energy Information Administration (EIA) notes only 12% of electricity consumed in the U.S. comes from renewable sources. Of that figure, only 11% comes specifically from solar energy. Approximately 79% of electricity consumed comes from fossil fuel sources that are warming our planet at alarming rates. Shifting to higher levels of renewable energy is tied to the United Nation’s goal to limit global warming to 1.5 C to tackle climate change and minimize its impact by 2030.

(References: U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy; U.S. Energy Information Administration; and UN Climate Action Goal 13.)

Elevator pitch: Only 12% of electricity consumed in the U.S. comes from renewable sources and as a result, our dependency on fossil fuels has caused rising issues such as climate change. A simple, effective, and low-cost solution to accelerate the transition to renewable sources is by increasing the efficiency of current solar panels by applying a phase change material to serve as thermal management thus preventing a decrease in power output. 

 

Micro: Lehigh and the Bethlehem area need solar panels to be more efficient to consume electricity with renewable sources and work towards offsetting natural gas usage.

Elevator Pitch: The reliance on fossil fuels has resulted in negative impacts such as large amounts of carbon dioxide being released. A simple, effective, and low-cost solution to accelerate the transition to renewable sources is by increasing the efficiency of current solar panels by applying a phase change material to serve as thermal management thus preventing a decrease in power output.

 

2. Based on your life experience, skills and interests, what would a design process that is both uniquely yours and effective look like?

As a result of my experience of working on projects in classroom settings such as creating a product for a specific polymer and outside classroom settings such as researching quantum dot sensitized solar cells, I have learned that a design process is not linear and involves a lot of revision which could lead one back to the beginning. An effective design process begins with establishing what the problem is to then be able to create an outline of the necessary steps needed to solve the problem and have a clear understanding. Next is gaining knowledge of the topic and problem at hand. Not only is gaining knowledge important but also then fact-checking with professionals in the topic field to validate and reinforce one’s knowledge. At this stage, it would also be beneficial to talk to stakeholders to learn about other potential needs the problem might bring about.

Once a list of needs is created then ideas can be developed to solve the problem. It is important at this stage to reach out to professionals for additional insight. During this stage, testing of materials, reaching out to customers, and brainstorming is all welcome. Next, the ideas should be thoroughly evaluated on the basis of economic value, ethicality, feasibility, and desirability. To evaluate each pillar, it is important to compare the idea to other ideas in the world, learn where materials are being sourced from, contact customers and potential stakeholders. It is important to note that it is possible that a good idea might not be generated but this just means to go back to step zero and redefine the problem to something more attainable yet can cause impact. Once an idea is selected, then it should be tested out in the customer market and further evaluated on its own to determine the future success of the idea in solving the problem.

In summary, an effective design process consists of defining the problem, gaining knowledge and fact-checking, contacting stakeholders, coming up with ideas to solve the problem, evaluating based on the four pillars, and testing. 

 

3. You have begun to talk to stakeholders for your project and will continue to do so going forward. For these conversations, list 10 hypotheses for your project that you will need to validate, 10 assumptions your project is making, and the basis for those assumptions.

Hypotheses:

1. Commercial grade Calcium Chloride Hexahydrate, CaCl2* 6H2O, as a phase change material (PCM) has the necessary latent heat of fusion to maintain solar panels at a constant temperature.
2. Placing a PCM behind a solar panel will increase the energy efficiency of the panel and serve as an energy storage mechanism.
3. Putting a heat sink behind the PCM will further increase the efficiency of the solar panel.
4. Solar panels combined with PCM will have a lower chance of undergoing damage at different temperatures and seasons. 
5. Solar panels with PCM will be more efficient than solar panels not integrating PCM under similar climate conditions.
6. Solar panels with PCM will have a higher life expectancy than solar panels without PCM.
7. The commercial-grade Calcium Chloride Hexahydrate will have a constant heat of fusion throughout the life expectancy of the solar panels.
8. The box containing the PCM will be structurally able to withstand any weather conditions.
9. Solar panels with PCM will be affordable to customers and there is an economic value of the addition of PCMs. 
10.  The materials used to create the PCM will be ethically sourced and have a factor of recyclability.

Assumptions and Basis:

1. Commercial-grade CaCl2* 6H2O has a fairly constant heat of fusion on the basis that commercial-grade CaCl2* 6H2O is impure.
2. Commercial-grade CaCl2* 6H2O will not produce any gas on the basis that commercial-grade CaCl2* 6H2O has a high heat of vaporization.
3. The experimental and control solar panels will be exposed to the same conditions on the basis that a heat lamp will be hitting both panels at the same time.
4. The efficiency of solar panels decreases thus resulting in a power drop as temperature increases. The graph below from a previous study demonstrated that as the temperature increased from 28 degrees celsius to 80 degrees celsius there was a significant decrease in power in crystalline silicon solar cells.
5. PCM can be used to extract heat from solar panels. A study in Indonesia demonstrated that a solar panel combined with a PCM decreased the temperature of the panel by 10 degrees Celsius (1).
6. PCM can increase the efficiency of the solar panel. A study in Malaysia demonstrated that a PV-PCM panel resulted in an increase from 8.3% to 10.1% (1). 
7. The use of PCM and fined heat sinks will contribute to the thermal management of the solar panel. A study conducted in New Zealand on photovoltaic cells using PCM-infused graphite and aluminum fins demonstrated that a constant temperature could be maintained over a period of time (2).
8. Approximately 10 thermocouples (T/C) will be necessary for temperature detection based on previous studies where a similar amount of thermocouples were used to collect data.
9. Using 2 resistance temperature detectors (RTDs), although more precise than T/Cs, will be sufficient to keep costs down.
10. We will need insulation around the T/Cs and RTDs.

 

Sources:

1. Sourav Khanna, K.S. Reddy, Tapas K. Mallick, Optimization of finned solar photovoltaic phase change material (finned pv-pcm) system, 2018
2. Peter Atkin, Mohammed M. Farid, Improving the efficiency of photovoltaic cells using PCM infused graphite and aluminum fins, 2015