Reasons why you CANNOT use Peltier for air conditioning

Summary

In this video, the creator debunks the misconception that Peltier-based thermoelectric coolers can serve as effective air conditioners. By analyzing performance curves and doing simple math, the video explains that while these devices can reach very low temperatures, they cannot provide the cooling power necessary for a functional air conditioning system. The creator emphasizes that even with 20 Peltier units, the cooling output is insufficient, and the energy costs to run them would be high. In contrast, commercial air conditioning units are more cost-effective, reliable, and efficient for cooling large spaces.

Takeaways

• 😀 You cannot build an efficient air conditioner using a Peltier thermoelectric cooler alone.
• 😀 Peltier devices can achieve very low temperatures but fail to provide enough cooling power to be effective in air conditioning applications.
• 😀 The cooling performance of a Peltier device decreases significantly as the temperature difference (ΔT) between the hot and cold sides increases.
• 😀 The cooling power of a Peltier device is measured in watts, not the power it consumes from the power supply, which makes it hard to reach sufficient cooling power.
• 😀 Even with high performance, a Peltier device might only provide a cooling capacity of around 100 watts, which is insufficient for cooling a room.
• 😀 Insulating the cold side of the Peltier device and considering heat loss is essential for any practical cooling application.
• 😀 A simple experiment of using multiple Peltier units is not feasible due to the significant cost of power supplies and the limitations of cooling power.
• 😀 Traditional air conditioning systems use much higher cooling power, typically in the range of 2000 watts, compared to a Peltier unit’s 100 watts.
• 😀 The total cost of setting up a Peltier-based cooling system with multiple units and power supplies becomes prohibitively expensive, often exceeding $600.
• 😀 Proper air conditioning systems are much more efficient, and a regular AC unit can be purchased for around $300, offering significantly better performance.
• 😀 Building an air conditioning unit using Peltier coolers is an experiment that will waste resources and time, as it cannot replace a traditional AC unit effectively.

Q & A

Why can't you build a reasonable air conditioner using Peltier devices?

Peltier devices, while capable of creating temperature differences, do not provide enough cooling power to effectively cool a room. Their cooling performance decreases significantly as the temperature difference (ΔT) increases, and the amount of heat they need to expel is too high for practical use in air conditioning.

How do Peltier devices work to cool air?

Peltier devices work by creating a temperature difference between their two sides. The hot side absorbs heat, and the cold side releases it. This process relies on the flow of current through semiconductor materials that cause heat to be pumped from one side to the other, creating a cooling effect.

What does the performance curve for a Peltier device show?

The performance curve for a Peltier device shows the relationship between the temperature difference (ΔT) and the cooling power (QC). It helps you understand how much heat the device can move at different temperature differences between the hot and cold sides.

What happens when you try to achieve very low temperatures with a Peltier device?

When attempting to achieve very low temperatures, the cooling power drops significantly. For example, if the cold side temperature is very low, the heat transfer becomes inefficient, and the device might not be able to cool anything effectively, even if the temperature difference is high.

Can a Peltier device cool a large room effectively?

No, a single Peltier device cannot cool a large room effectively. The cooling power is too low, even if you use multiple devices. A typical air conditioning unit provides much more cooling power, making Peltier devices unsuitable for this application.

How does the required power for Peltier devices compare to a traditional air conditioning unit?

Peltier devices require a large amount of power to operate, with one unit consuming around 225 watts to pump just 100 watts of cooling. In contrast, traditional air conditioners can cool a room with much higher power, such as 2,000 watts, and are more efficient in removing heat.

Why is it not practical to build an air conditioner with Peltier devices from a cost perspective?

Building an air conditioner using Peltier devices is not practical due to the high cost of purchasing multiple units and the required power supplies. Additionally, the cooling power provided by Peltier devices is insufficient, and the amount of heat that needs to be dissipated makes the setup inefficient and expensive.

What are the limitations of using Peltier devices for cooling applications?

The main limitations of using Peltier devices include low cooling power, high energy consumption, difficulty in dissipating heat from the hot side, and high costs for the required components. These factors make Peltier devices unsuitable for applications like air conditioning.

How does the cooling power of a Peltier device change with current and temperature difference?

As the current increases, the cooling power of a Peltier device increases. However, as the temperature difference between the hot and cold sides increases, the cooling power decreases. This inverse relationship limits the device's effectiveness at high temperature differences.

What alternatives exist for cooling a room more effectively than using Peltier devices?

Traditional air conditioning units are much more effective at cooling rooms, as they can provide a cooling power of 2,000 watts or more. These units are designed to efficiently remove heat and are much more cost-effective and practical compared to a Peltier-based solution.