Testing different Peltier coolers by cooling/freezing water - Part 3/1 - TEC12706 | Summary and Q&A

TL;DR

The TEC Club 706 unit's cooling performance was analyzed under load, yielding unexpected results in freezing time and temperature.

Key Insights

• ⌛ The test illustrated that practical results can differ significantly from theoretical expectations, especially regarding time and temperature dynamics.
• 😎 The setup emphasized the importance of understanding thermal dynamics and the impact of a significant temperature difference on cooling efficiency.
• ✋ High-quality connections and upgraded equipment were crucial for safely conducting experiments at higher currents.
• 😎 The cooling performance of the TEC unit is sensitive to variations in environmental temperatures and system insulation.
• 👻 Data collection technology improvements allow for better monitoring and down to millimeter precision in thermometric readings.
• 🥋 The experiment demonstrated the necessity of stirring in a freezing process, revealing critical insights into uniform temperature distribution.
• 🥵 The role of latent heat in phase changes was pivotal in determining the final cooling performance of the system.

Transcript

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Questions & Answers

Q: What was the main objective of testing the TEC Club 706 unit in this video?

The primary goal was to assess the cooling performance of the TEC Club 706 unit under a defined heat load consisting of 100 grams of water at 23 degrees Celsius. The objective was to establish how effectively the unit could bring the water to freezing and subsequently below zero degrees Celsius, allowing for analysis of its practical operating performance.

Q: How did the results of the freezing test compare to the initial expectations?

Contrary to expectations that the water would freeze within approximately six minutes, the freezing process took significantly longer, with parts of the water remaining unfrozen after almost an hour. This marked disparity raised questions about both the cooling power of the TEC unit and the heat transfer dynamics without agitation in the water.

Q: What role did the hot side temperature play in the test outcomes?

The temperature of the hot side appeared to be higher than anticipated, estimated at around 35 degrees Celsius when it was originally assumed to be 30 degrees. This increase likely impacted the performance and efficiency of the cooling process, reducing the effective cooling power of the TEC unit and contributing to the extended time required for freezing.

Q: What was mentioned about the setup of the cooling experiment in terms of safety?

Safety measures taken included the use of upgraded connecting cables that could handle higher currents without overheating, addressing previous concerns where earlier cables became warm at higher amperages. This reflects a priority for avoiding potential fire hazards and ensuring a safe experimental environment.

Q: How did the absence of stirring affect the freezing process?

The lack of stirring led to uneven temperature distribution within the water tank, which is critical for efficient freezing. Still water creates 'blind spots' where certain areas remain liquid while others begin to freeze, prolonging the overall freezing time and yielding inconsistent measurements across different points in the tank.

Q: What improvements were made to the monitoring equipment for this experiment?

New screw-type banana plugs were introduced for easier connections, and a four-channel thermometer that could save data to an SD card was used for more effective temperature monitoring. This setup enhances data collection accuracy and eliminates the requirement of separate monitoring devices.

Q: How does the latent heat of fusion affect the freezing process?

The latent heat of fusion represents the energy required for water to change from a liquid to a solid state without changing temperature. In this scenario, approximately 334 kiloJoules per kilogram must be overcome, which significantly extends the time to cool water below zero degrees after it has reached freezing point, as the system must first remove this energy before further cooling can happen.

Summary & Key Takeaways

• The video is the second installment of a freezing test series focused on the TEC Club 706 cooling unit, specifically a 6 ampere model. The presenter examines its performance under a defined heat load.

• A 100-gram water sample at 23 degrees Celsius is used to measure how effectively the unit freezes the liquid and assess its operational efficiency with regards to current input and environmental conditions.

• Initial calculations expected the system to achieve cooling to zero degrees Celsius in approximately six minutes, but results showed discrepancies in actual freezing time and temperature measurements.