Why does ice build up in freezers?

Ice build-up is a common occurrence in freezers, whether at home or in large commercial environments like food factories. Addressing excessive ice build-up in these commercial environments is vital for employee safety and product quality. To tackle this issue effectively, it is helpful to have a basic understanding of the science behind ice build-up.

Ice formation begins with the presence of a liquid. In most cases, liquid isn’t directly exposed to freezing conditions, so where does this liquid come from that leads to the development of excessive ice build-up? The answer lies in moisture, which exists as a diffused liquid, carried as vapor in the air around us.

A key concept is relative humidity (RH)

This is a measurement that quantifies the amount of moisture within a given volume of air. The RH formula gives a percentage which indicates how much moisture the air contains, compared to its total moisture-holding capacity. When RH reaches 100%, the air is saturated with moisture, meaning it is holding the maximum amount it can.

Analysis

Warmer air has a higher moisture capacity than colder air. For instance, air at +15 degrees Celsius can hold more moisture than the same air at -15 degrees Celsius. Rapid temperature shifts from warm to cold can lead to significant changes in relative humidity and, in some cases, cause the air to reach its saturation point, known as the dew point. This sets the stage for precipitation—water droplets—forming. In a freezer environment, these water droplets freeze, resulting in the formation of ice.

To overcome excessive ice build-up in freezers, it’s imperative to minimize the entrance of warm and moist air into the freezer. This can be achieved by controlling ventilation and air quality, maintaining consistent operating temperatures and ensuring your freezer door is the correct solution for the application.

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Summary

An understanding of the correlation between moisture, relative humidity, and temperature is crucial in managing ice build-up. By grasping these principles, we can design and maintain freezer environments that effectively mitigate ice formation, ensuring both operational efficiency and product quality.