An industrious examination is the only methodology worth adopting when the mechanisms running walk-in freezers need clarification. There are the obvious components, the composite insulating panels and cooling units, parts that require little explanation, but the purposes of pressure relief valves don’t subscribe to easily relatable guides. Instead, this essential component needs its own detailed set of instructions, so let’s begin our engineering-oriented tale by taking a look at pressure equalization needs.
Walk-In Freezers and Pressure Equalization
Fatigue runs up the arms of hard-working employees when they tug the door handle on a walk-in freezer. A pressure differential has built up between the outside of the chamber and its frosty interior. Atmospheric pressure rules outside, but the artificial environment inside the freezer is maintained at a slightly different level. The actions of the cooling unit and its fan are partially responsible for this effect, with the fan drawing warm air out of the sealed room. Pressure release vents (PRVs) equalize this unwanted differential, thus removing the need for muscled arms every time the chilled alcove needs to be accessed.
Accounting for Intrusive Air
There’s typically no airlocks provided outside a walk-in freezer, so the pressure relief vents come to the rescue again when warm air enters the sealed chamber via an open door. Remember, a walk-in freezer door is an invaluable part of the equipment roster, but its functionality is blunted when it’s continually opened and closed throughout the working day. The venting solution handles excess warm air by ejecting it and rebalancing the pressure inside the coolroom environment.
Staying Cool with a Negative Environment
The thermodynamic characteristics of a sealed and cooled freezer dictate the pressure variables we mentioned earlier. Typically, this is a negative value, so the room wishes to address this vacuum by pulling in more air. Unfortunately, this would draw in an airflow that is substantially warmer. The ice would rapidly melt and then refreeze in accordance with the thermostat setting. In short, the interior climate would fluctuate wildly. Fortunately, pressure relief vents prevent these fluctuations by taking care of negative pressure differentials.
Thanks to this valve or venting solution, there’s no longer a need to call on the most musclebound staff member just to open a sealed door. Likewise, negative atmospheric variances are balanced by pressure relief devices, for they’re designed to regulate the internal atmosphere when active fan cooling units and dramatic temperature drops generate undesirable pressure variances
Some dynamic duos fight the elements, not costumed villains. In freezers and coolrooms, for instance, two forms of Polystyrene battle energy losses. Expanded Polystyrene (EPS) receives a mention first due to its immensely popular application base. The second member of this heroic pairing ranks almost as highly, although this latter energy champion is extruded, not formed from a closed-cell expansion process. Let’s take a look at both of these variations on a theme to see where they fit within freezer and coolroom designs.
Foam Insulating Panels
The general uses of this ubiquitous foam vary dramatically. Fragile items are packed in polystyrene foam. Food and drink cartons use that same packaging feature, except the product also leverages the thermal insulating properties of the foam to keep meals warm and beverages cool. Now, with this information in mind, EPS is an obvious choice for composite wall insulating panels, for its closed-cell build forms the core of some of the finest aluminium-bonded insulation panels on the market. The laminated pairing is light, certain to eliminate energy leakages, and as strong as any other toughened aluminium fixture.
Extruded Plastics Excel in Coolroom Environments
This is still the same polymer, but the material has been processed in a slightly different manner. The result is a soft plastic, but it’s more rigid than its foam-based cousin. Expect to see extruded freezer bags with zip-lock tops using this material. Likewise, well-defined containers employ the soft plastic. These larger containers, complete with lids, are manufactured from high-walled form factors to store large quantities of perishable items. Now, a summation of these features would seem to target extruded poly at the container sector, especially since these containers are very common in kitchens. But this multitalented plastic isn’t confined to portable containers, for it can swap places with expanded foam cores. Structurally rigid, this extruded core again binds to a pair of aluminium outer faces to create a formidable thermal barrier, one that’s easily installed as modular paneling in a freezer or coolroom alcove.
General use expanded foam, sometimes called styrofoam, is used in coffee cups, carry-out containers, and countless packaging applications. It’s also used in composite wall panels and concrete flooring as a thermal barrier. Meanwhile, extruded polystyrene also performs proficiently within packaging scenarios, though its soft outlines do bias the material towards food containers. The soft plastic is extruded for freezer bags, food containers, and used within the cores of laminated wall insulating panels.
C&M Coolrooms can create a custom solution for your specific needs. Talk to one of team members today.