Between November 11th to the 25th, Team 26 was focused on completing Milestone 1 - Design Phase 1: Initial Concept & Milestone 2 - Design Phase II. Within Milestone 1 Team 26 had tasks that were centered around gathering all the components of the system that would be required for us to execute on cooling the solar panel. Not only that, but creating an initial 3D Solidworks Model of the system was the main & final task that was achieved within the first few days of these past two weeks. With Milestone 2 we were able to utilize the 3D Model renderings of our initial cold plate design which is listed below as Figure 1.
Figure 1: Initial Cold Plate Design
Based on our initital cold plate deisgn and after conferring with experts in the field such as Dr. Ben Xu who provided us with certain improvments to our cold plate design and how to do the convection analysis of the design through a platform called Ansys Fluent. With the improvements made to the initial design, Figures 2 & 3 showcase the second iteration of design that Team 26 created and ran simualtions to determine the Velocity Contour for distirbituion of the coolant fluid.
Figure 2: Second Cold Plate Design
Figure 3: Second Cold Plate Design's Velocity Contour
With the modeling provided through Ansys, the fluid distribution based on the velocity contour was not uniform enough so we decided to redesign the cold plate leading to our final design. Team 26’s final design for the liquid cooled cold plate system consists of the following components: solar panel, cold plate, water pump, heat exchanger, tubing, tube fittings, tube clamps, and water. The cold plate will be attached to the back of the solar panel, the water pump will transport water from the water tank to the cold plate taking the heat away from the solar panel. The fluid will then move out through the cold plate outlet leading to the heat exchanger which will transfer the heat from the fluid to the atmosphere. Once the fluid is cooled, it will return to the water tank. For our cold plate design, we decided on a uniformly distributed tree design as you can see in Figure 4 below.
Figure 4: Final Cold Plate Design
This will allow the fluid to cover as much surface area as possible to take more heat away from the solar panel which is shown in Figures 5, 6, & 7 below.
Figure 5: Final Cold Plate Solid Temperature Contour
Figure 6: Final Cold Plate Fluid Temperature Contour
Figure 7: Final Cold Plate Velocity Contour
The main issues of our problem is the ability of our system to take a useful amount of heat away from the solar panel, making sure that the amount of effiniciecy lost gained back is of a useful amount, as well as making sure that our system will not use more energy than it gains back. As stated previously, Team 26 will use the uniformly distributed tree design as it will allow the fluid to take more heat away from the solar panel. Team 26 will perform a Levelized Cost of Energy analysis to show how well our system will work in the long run. The team has also decided against using a chiller to make our fluid cooler as it would use too much energy which would be counterproductive to what our cooling system is trying to achieve.
Going based off the modeling that we were able to do for the final design using Ansys & Solidworks, the analysis we were able to procure is shown below in the equations below. The first set of vaues we were able to procure was from the Ansys mdel itself which was the outlet temperature.
Table 1: Ansys Model Temperature Output Value
Variable | Value |
Mass Flow Rate (kg/s) | 0.08867 |
Temperature of Input flow | 26.7 C |
Temperature of Output Flow | 46 C |
With those values procured we were able to conduct analysis of the heat exchanger based on the equations below & Table 2 having the calcualted values.
Q = Heat Load of Device
m = Mass Flow Rate of Water
C_p = Specific Heat of Water
T_f,out = Temperature of Output Flow
T_f,in = Temperature of Input Flow
G = Solar Radiation Intensity
A_pv = Area of the PV Panel
Table 2: Caluclated Heat Load of System
Variable | Value |
Mass Flow Rate (kg/s) | 0.08867 |
Specific Capacity of Water (J/g*K) | 4.186 |
Temperature of Output Flow | 46 C |
Temperature of Input flow | 26.7 C |
Heat Load Calculated | 7.1636 KW |
And the final analysis we were able to compute was the effcicney analysis, thermal efficency to be exact using the below equation and Table 3 contains the calcualted value of thermal efficiency.
η_th = thermal efficiency
m_w = mass flow rate of water
c_w = specific capacity of water
T_f,out = Temperature of output flow
T_f,in = Temperature of input flow
G = Solar radiation Intensity
A_pv = area of the PV panel
Variable | Value |
Mass Flow Rate (kg/s) | 0.08867 |
Specific Capacity of Water (J/g*K) | 4.186 |
Area of the PV Panel | .53086 m^2 |
Temperature of Output Flow | 46 C |
Temperature of Input Flow | 26.7 C |
Solar Radiation Intensity | 1380 W/m^2 |
Thermal Efficiency | 10.13% |
Looking forward to Capstone II, Team 26 will have met with Dr. Ben Xu before the end of the Fall 2023 semester to show him our Ansys results and to gain his expertise and any feedback he has on our design to make sure that it will be ready for fabrication. Team 26 will also set up a meeting with a machinist before the beginning of the Spring 2024 semester to discuss our fabrication process, and show them our design and all of the fine details to gain their expertise on the fabrication process that we should pursue. During the winter break, Team 26 will acquire the materials required to fabricate our cold plate such as the Aluminum 6061, as well as the other items required to build our system such as the water pump, heat exchanger, tubing, tube fittings, and the rest of the items listed in our bill of materials to have them ready once the cold plate is fabricated to connect everything together.
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