By creating a more uniform temperature throughout the space, HVLS fans can help minimize the chance of freezer burn on products stored near the floor. Uniformity also yields a reduction in energy usage since the freezer doesn’t have to work as hard to maintain the desired temperature. (NOTE: This does not apply to blast freezers.)
Additionally, the gentle breeze HVLS fans provide helps prevent condensation—one of the key contributors to food spoilage in refrigerators. HVLS fans also fight mold growth inside the refrigeration unit, which saves companies time and money in mold removal expense.
Humidity is an even larger issue than condensation. Most often, humidity control applications involve partitioning humidity spaces: separating a higher humidity space (such as a leafy vegetable storage area) from a lower humidity space.
Maintaining a low humidity space in the midst of a high humidity environment requires two basic components: 1) an insulated barrier to surround the space, and 2) a mechanical chiller to de-humidify, cool, and circulate the air within the space. An insulated barrier is desired so that the exterior surface of the barrier does not become so cold that its temperature drops below the exterior (higher humidity) dew point, thereby causing condensation (moisture) to form on the exterior of the barrier.
While traditional walls are often used for developing such a barrier, insulated fabric curtain walls are becoming increasingly popular for a number of reasons. With an exterior made of 18-ounce industrial vinyl, they are quicker and easier to install than traditional walls and can be moved or re-configured should a plant’s needs or layout change. Also, vinyl-covered surfaces of most curtain walls are inherently waterproof, protecting the insulation inside from the effects of condensation. Additionally, higher quality curtain walls are treated with an anti-microbial agent to prevent mold or mildew should moisture manage to migrate inside the curtain through a tear or scrape. Finally, the reduced heat transfer across the insulated curtain wall allows the mechanical chilling equipment to operate using less energy.
The principles are the same in the case of maintaining a high humidity space, at least from the standpoint of the barrier. While a mechanical chiller is not used, some source of moisture is, whether it be misting sprinklers or the addition of high humidity air flow into the space. Inhibiting heat transfer is less important in a high humidity space. However, the insulated curtain wall still plays a major role in reducing temperature fluctuations that can trigger changes in relative humidity.
Blast Freezers and Curtain Walls
Fabric curtain walls are also becoming more common in blast freezer applications. While blast freezers have become widely accepted across the food industry, their huge size, combined with other issues like pressure and frost build-up, can be problematic. In some cases, their enormous doors (which can be as a large as 25 feet by 25 feet) have become so heavy and hard to open that employees have resorted to dangerous methods to open them, such as using forklifts. Expectedly, shutting blast freezer doors also presents an obstacle. This is a major problem, since energy is quickly lost if the doors are not closed completely and correctly.
Blast freezer curtain walls are made of insulated, sliding panels nested in a tubular steel frame. Each panel is constructed of 18-ounce, industrial vinyl fabric surrounding a layer of anti-microbial polyester batting. Engineered to be light and easy to use, blast freezer curtain walls form a safe and affordable airflow and thermal barrier and can be operated by a single person. Their tight and effective seal redirects the chamber’s airflow, increasing efficiency, reducing blast cycle times, and lowering energy consumption.