Building-Integrated Solar Panels

Team 2C: Solar Panels Presentation Video: https://mediaspace.carleton.ca/media/Building-Integrated%20Solar%20Panels%20%28Team%202%20CCDP2100-C%29/1_shjvjfaw

Overview

This presentation is about our groups findings on building-integrated solar panels and how they can be the next main source to heat homes and buildings. Building-integrated solar panels offer the ability to reduce the level of carbon emissions in order to help sustain our planet for a long period of time. Below, Alexei will discuss PV-cells, Zeid will discuss solar collectors, Nathan will discuss the solar panel cooling and the methods, and finally Nick will discuss thermal storage. The presentation will close with a summary of the entire system as shown above in Figure 1.

Figure 1:  Building-Integrated Photovoltaic System [1]

PV Cells: Alexei

A photovoltaic cell consists of 3 layers. The top layer is made of silicon and a small amount of phosphorus. This makes the top layer more negatively charged. The bottom layer is made of silicon and a small portion of boron. This gives the bottom layer fewer electrons, making it less conductive [3]. By joining these two types of semiconductors, an electric field is formed as electrons move to the positive p-side and protons move to the negative n-side. This field causes negatively charged particles to move in one direction and positively charged particles in the other direction. The middle layer is a thin layer and essentially neutral. This is where the breakup of photons begins. Wavelengths of 350 nanometers to 1140 nanometers are absorbed. Once you connect the top and bottom with electrical wiring, electrons begin to flow from the PV cell into the wire. The flow of electrons is electricity. The photoelectric effect is when light hits a material and electrons disperse [4]. The electrons absorb the light, and if they get enough energy, they are able to break free of the material’s surface.

Figure 3: Photoelectric Effect [2]

Solar Collection: Zeid

Light is any kind of electromagnetic wave: microwaves, sunlight, X-rays. This means that sunlight possesses wave-like properties: reflection, refraction, absorption etc . Light transmission is when light travels through a medium without being affected [6]. In order to maximize solar energy collection, light transmission must be maximized. This is done by optimizing the material, thickness and orientation of the solar collector. The glazing is the top cover of the solar collector, it transmits solar light to the absorber plate with minimum loss [7]. It was proven that the optimal thickness for the glazing is four millimeters, it improved solar energy collection by almost 10%. The optimal angle for the glazing is dependent on the latitude it was set up. Research has determined that the optimal angle for solar collectors in Ottawa to be slightly below the latitude with respect to the area, which is around 44°. This results in improvement of solar energy collection efficiency by 30%.

Figure 2: Reflection, Refraction, Absorption, Scattering and Transmission of Solar Light [5]

Solar Panel Cooling: Nathan

Solar panel cooling is an important aspect of maintaining and improving the efficiency of solar panels. As the temperature of a solar panel rises, the efficiency decreases by approximately 0.5% for every degree beyond about 50℃ [8]. To cope with the extreme temperatures that solar panels can reach, there are methods that can be used to cool solar panels. Passive solar panel cooling protects the solar panels, as well as the buildings from excess heat from the sun. Three of those methods include cooling through radiation emission and reflection (where the solar panels automatically reflect away and emit certain radiations), cooling using air movement and moisture (where excess heat is transferred to moisture in the air, causing it to evaporate) [9], and cooling using thermal storage hybrid systems (where water or air is circulated from the solar panel to the thermal storage unit; removing heat from the solar panels and leaving it in the thermal storage). Each of these methods improve the efficiency of solar panels by ensuring that the solar panels remain at or below 50℃. The hybrid cooling system that features the thermal storage unit was found to increase the efficiency of solar panels by up to 50% [8]. The first two cooling methods explained can be seen above in Figure 4.

Figure 4: Solar Panel Cooling Methods [Nathan Miller]

Thermal Storage: Nick

Heat is high energy particles moving at very high speeds which contain lots of kinetic energy. These high energy particles can transfer their energy by direct contact (conduction) and when the heat disperses and travels away from the collison, this is the process of convection. The thermal storage unit takes electricity provided by the solar panels to heat up the water [11]. Inside a thermal storage unit, water is being heated up by the heating rods inside the storage unit by conduction and then the heat is dispersed inside the container by convection [12]. Heat will transfer around the building by the use of in floor heating pipes. This process will move heat throughout the house and radiate heat from the floor. As the heat from the floor rises and disperses, convection will transfer this heat around the room.

Figure 5: Thermal storage system [10]

References:

 [1] The Zen Cart® Team and others, “Solar Hydronic Heating.” [Online]. Available: https://nlsolarheating.solartubs.com/solar-hydronic-heating-ezp-30.html. [Accessed: 19-Nov-2020].

[2]“What is the Photoelectric Effect? " Science ABC,” Science ABC, 04-Dec-2019. [Online]. Available: https://www.scienceabc.com/pure-sciences/what-explain-photoelectric-effect-einstein-definition-exmaple-applications-threshold-frequency.html. [Accessed: 19-Nov-2020].

[3] S. Holzner and About the Book Author Steven Holzner is an award-winning author of technical and science books (like Physics For Dummies and Differential Equations For Dummies). He graduated from MIT and did his PhD in physics at Cornell University, “How Physicists Solved the Photoelectric Effect of Light,” dummies. [Online]. Available: https://www.dummies.com/education/science/quantum-physics/how-physicists-solved-the-photoelectric-effect-of-light/. [Accessed: 08-Oct-2020].

[4] Courses.lumenlearning.com. 2020. Elasticity, Stress, Strain, And Fracture | Boundless Physics. [online] Available at: <https://courses.lumenlearning.com/boundless-physics/chapter/elasticity-stress-strain-and-fracture/#:~:text=Elasticity%20is%20a%20measure%20of%20the%20deformation%20of%20an%20object,in%20length%20over%20original%20length.> [Accessed 13 September 2020].

[5] “Overview of Radiation,” Electromagnetic Radiation, 2005. [Online]. Available: https://okfirst.mesonet.org/train/meteorology/Radiation.html. [Accessed: 10-Oct-2020].

[6]“Light Transmission,” Revic, 08-May-2018. [Online]. Available: http://www.revicoptics.com/research/light-transmission/. [Accessed: 21-Oct-2020].

[7] R. Bakari, R. J. A. Minja, and K. N. Njau, “Effect of Glass Thickness on Performance of Flat Plate Solar Collectors for Fruits Drying,” Journal of Energy, 12-Mar-2014. [Online]. Available: https://www.hindawi.com/journals/jen/2014/247287/. [Accessed: 21-Oct-2020].

[8] K. A. Moharram, M. S. Abd-Elhady, H. A. Kandil, and H. El-Sherif, “Enhancing the performance of photovoltaic panels by water cooling,” Ain Shams Engineering Journal, 16-May-2013. [Online]. Available: https://www.sciencedirect.com/science/article/pii/S2090447913000403. [Accessed: 05-Nov-2020].

[9] B. Zhao, M. Hu, X. Ao, Q. Xuan, and G. Pei, “Spectrally selective approaches for passive cooling of solar cells: A review,” Applied Energy, vol. 262, p. 114548, 2020.

[10] H. Now, S. Illustrations and R. Building, "diagram of a classic colonial house with ground source heat pump with...", iStock, 2020. [Online]. Available: https://www.istockphoto.com/vector/heat-pump-and-solar-panels-diagram-with-hand-drawn-notes-gm622809182-109082841. [Accessed: 01- Nov- 2020].

[11]"Thermal Energy Storage - an overview | ScienceDirect Topics", Sciencedirect.com, 2020. [Online]. Available: https://www.sciencedirect.com/topics/engineering/thermal-energy-storage. [Accessed: 30- Oct- 2020].

[12] "Convection - an overview | ScienceDirect Topics", Sciencedirect.com, 2020. [Online]. Available: https://www.sciencedirect.com/topics/materials-science/convection. [Accessed: 08- Oct- 2020].