Process and Operations / Chill: Refrigeration and Freezing

MRO Q&A: Excessive Snow in Freezer

A reader asks how to handle an excessive amount of snow in his plant's freezer.

Q: We freeze our own products and we have an excessive amount of snow in our freezer. How do you combat this?

A: Snow formation in freezers is a common problem in the food industry. In order to develop snow you must have moisture, and it is either coming from the outside of the freezer or the inside.

Let's start by assuming it is coming from outside of the freezer. The first thing to check is for roof and wall breaches where outside air can infiltrate the freezer. If air can get in, then cool air from the freezer can escape. Performing a thermograph on external roof joints and the intersections of walls and roofs will show any leakage occurring.

The moisture may just be coming through the entrance door to the freezer. It is important to make sure that the makeup air pressure inside the freezer is slightly greater than outside. This will cause some refrigerated air to leave the freezer but will minimize snow build up, along with keeping flying pests at bay. Many facilities utilize high-speed roll-up doors to minimize the amount of time the outside and inside environments meet.

After you have verified the building envelope is secure, you must address the humidity load that's inside the freezer from your product. You will need to remove the moist air from the room while not wasting the BTUs you have invested in cooling that air. The use of an energy wheel is a great tool for this application. The air passes through one hemisphere of a wheel coated with media that absorb the BTUs from the air while the wheel is turning. That same air is now discharged back into the room after it passes through the other hemisphere of the turning wheel so it can reclaim the BTUs prior to being directed back into the freezer. These units are not inexpensive but, in cases where there are many people going in and out of a freezer, the liability from slippery floors due to ice may make good sense.

Once these two areas are addressed you will be on your way to minimizing snow formation.