As we prepared to continue work on our project, the Greater Houston area was threatened by Hurricane Nicholas of Category 1, which resulted in the school closing Sept. 13-14 due to possible flooding and strong winds. This natural event delayed when our team would meet by a couple of days and resulted in a shorter limited time for once we met again on Wednesday, Sept. 15. We began to set up our system, now integrating the water-cooling loop to cool down the Peltier devices and as we were ready to begin testing and gather data, we noticed the water pump for the water-cooling loop was no longer operational and we weren’t able to test our system that day. Once we got our hands on a new water pump, we began to run tests on multiple configurations and gather data so we can catch-up for the days lost and compare the two designs to each other. The first test, shown in Figure 1, was a basic model of our original system design using a heat sink and fan. We collected temperature values for the water and heat sink over time as our system operated, shown in Figure 2. The results were lackluster as we had determined they would be in our preliminary tests.
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| Figure 1 |
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| Figure 2 |
We already made new design modifications to instead cool our system using water and a radiator. Our second test, shown in figure 3, was much more impressive as the data shows in Figure 4. Note the purpose of these tests is to determine the relative efficiency of our system to make improvements.
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| Figure 3 |
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| Figure 4 |
Our third was on September 23 and we incorporated a new device to regulate our amp input to better control our system. Also, we tried to incorporate two new switches to reverse the polarity of the Peltiers to alternate from cooling to heating. We were unable to properly do this( We wired the switches wrong, but did not know that at the time), but we were able to run the tests and will add the switches for our next tests. For our third test, shown in figure 5, we added more fans to our radiator, and set our amp input to two Peltiers in parallel at 10 amps total resulting in 4-5 amps each due to fluctuation in current draw due to temperature. The results show a large improvement in the cooling water temperature, Figure 6.
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| Figure 5 |
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| Figure 6 |
The fourth test, shown in Figure 7, We added two more Peltiers, another cooling waterblock, another voltage regulator, and a clamp to hold our Peltier system in place. We ran a cooling and heating test and our results are shown in Figure 8. This was the most impressive test yet. We managed to achieve a Delta T of 50-55 °C using about 150 total Watts spread evenly between 4 Peltier units. In our future tests we intend to measure our water volume and add a heat load to simulate the system when it is fully integrated into a cushion.
Figure 7
Figure 8
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