Thermogard blog

How do Gel Ice Packs really work?

Written by Gypsy Smith | May 23, 2024 1:00:00 AM

Gel ice packs are a common fixture in daily life, appreciated for their benefits without much consideration for the science behind them. Gel ice packs are an essential tool for keeping items cold, and their efficiency stems from a combination of material properties and physical principles. Let's break down how they work:

What is a Gel Ice Pack?

A gel ice pack is a sealed, flexible plastic pouch filled with a mixture of water and a non-toxic gel. The specific composition of the Thermogard gel packs allow them to freeze quicker, and take thaw more slowly than plain water.

How does it work?

Phase Change

The key to a gel ice pack's effectiveness lies in its ability to undergo a phase change, which is the transition between solid and liquid states. When a gel ice pack is placed in a freezer, the gel inside it absorbs heat from its surroundings and eventually freezes. This process stores thermal energy within the gel.

Freezing and Heat Absorption

1. Freezing Process

When the gel ice pack is placed in the freezer, the ice pack absorbs the energy from the freezer. When it is unable to store any more energy, the pack will have frozen solid.

2. Heat Absorption

When the frozen gel pack is removed from the freezer and placed in an insulated container or on an object, it begins to absorb heat from its surroundings. The gel inside the pack begins to melt, changing from a solid to a liquid state. This phase change requires a significant amount of energy, known as the latent heat of fusion.

Consistent Cooling

During the phase change from solid to liquid, the gel pack maintains a constant temperature. As the gel absorbs heat, it melts slowly, ensuring a prolonged cooling effect. This process is more efficient than plain ice because the gel can absorb heat more consistently throughout its phase change before it fully transitions to a liquid state.

Insulation

The plastic pouch and any additional insulation in the packaging play a crucial role in enhancing the cooling effect. The insulation slows down the transfer of heat from the external environment to the gel pack, allowing it to stay colder for a longer period.

Benefits of Gel Ice Packs

  • Extended Cooling - The gel formulation extends the cooling duration compared to plain ice.
  • Reusability - Gel Ice Packs can be refrozen and reused multiple times, making them a cost-effective solution.
  • Non-toxic - The gel is non-toxic, making it safe for use with food and for medical applications.

Gel ice packs operate on the principles of heat absorption, phase change, and insulation. By leveraging the unique properties of the gel, these packs provide a reliable and long-lasting cooling solution for a wide range of applications, ensuring that items stay cold for extended periods. 

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