Where two adjacent spaces must be kept at different humidity levels, the most common solution is to use an insulated barrier wall or fabric curtain wall, along with mechanical humidity control devices such as chillers, humidifiers, and/or dehumidifying units.
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Explore This IssueJune/July 2017
On the other hand, in a large space, it’s quite common for humidity levels simply to rise too high. Overly humid air is an especially common problem in food packaging facilities where hot water is used in cooling and sterilization procedures. In this case, it might be necessary to install a large-scale industrial dehumidifying unit or system.
There are numerous types of industrial scale dehumidifiers available on the market. Some use chemical desiccants to remove moisture from the air. Others, such as direct-expansion systems and heat pipes, work in conjunction with the air conditioning system. Each system has its pros and cons in terms of cost, energy efficiency, and capacity.
Another approach that can be used on its own or in conjunction with an air-conditioning system is evaporation. This approach uses fans to create air movement that moves humid air away from the area. It also creates an evaporative cooling effect that can reduce worker stress. This is especially true of HVLS fans, which operate without creating undue drafts.
Condensation is, of course, a humidity issue. However, it is also a temperature issue. Condensation happens when warmer air flows over a cooler surface. If the surface is cool enough, the air will hit the dew point and coalesce into droplets, which then collect on the surface. It’s possible to have condensation even without overly high humidity, where temperature differentials are great enough. That said, high humidity exacerbates the problem.
Condensation is a common problem in warehouses, especially at humid times of year. It can contribute to all sorts of safety issues, such as sweating slab syndrome and slippery handrails, as well as compromising product quality. Because of the huge temperature differentials involved when coolers and freezers come into contact with warmer air, condensation is also a very common and serious issue when it comes to food storage.
There are two ways to fight condensation: reduce humidity or decrease temperature differential. The latter isn’t always possible in a food handling situation, since coolers and freezers by their very nature require a temperature differential. However, in certain cases, it is an effective approach. For instance, correcting air stratification problems in a large warehouse space can relieve condensation issues by creating a more uniform interior air mass as well as through the evaporative effect of moving air.
One of the biggest temperature control challenges for large food handling facilities and food storage warehouses is maintaining safe temperatures cost effectively. Implementing energy-efficiency measures can significantly reduce costly energy loss, but care must be taken to allocate resources on high ROI improvements. Considerations include the following.
Energy-efficient lighting. LED bulbs are the most efficient available, and their long life reduces maintenance costs significantly. They emit very little heat and therefore reduce cooling costs, and are cold-tolerant for efficient lighting for freezers and coolers. However, high-efficiency fluorescents usually cost less upfront and may be more cost effective, so it’s a good idea to run the numbers before investing in lighting.
Shell measures. Limiting energy loss through the building’s walls with measures such as insulation, weatherization, energy-efficient doors and docks, and cool roofs will significantly reduce HVAC costs. It will also allow cooling equipment to run less, which saves electricity and extends equipment life.
Pipe insulation. Older cold storage facilities should be examined for uninsulated or poorly insulated piping. Insulating just 400 feet of pipe can save a facility $27,000 per year, according to the Global Cold Chain Alliance.