Maximizing Energy Efficiency in Cold Storage Air Cooling
In the carefully controlled environment of a cold storage facility, the formation of frost on the evaporator surface is a common occurrence. Frost can impede the conduction and distribution of cooling capacity, ultimately affecting the efficiency of the entire refrigeration system. Addressing this challenge is crucial, not only for operational effectiveness but also for substantial energy savings. According to the Energy Trust of Oregon, electric defrost can account for 21% of the energy usage in a cold storage facility.
Simon Khaled, P. Eng
Vice President & Director of Sales, North America
Problem
Improper management of frost in a cold storage facility can lead to the formation of thick layers, impacting system efficiency. Effective defrosting becomes paramount for several reasons:
- Improving cooling system efficiency
- Reducing energy usage through fewer defrost cycles
- Ensuring product quality with a low temperature gradient
- Extending the life of cold storage system components by minimizing wear and tear
A significant challenge faced by these facilities is the escape of heat from air coolers, resulting in substantial energy waste. Inefficient defrosting compounds the issue, increasing the frequency of defrost cycles and consequently, operational costs.
Heat Saving, Water Repellant Solutions
Efficient defrosting is not only an essential function but also a substantial contributor to energy usage in cold storage facilities. The market offers various solutions, with a focus on reducing defrosting time to enhance the efficiency of cold storage air coolers. Some solutions may involve intricate techniques or specialized tools, but those that prevent heat from escaping the air cooler prove most effective.
The integration of a short fabric duct can increase air throw and promotes air mixing to create a uniform temperature distribution within the space. This solution increases defrost cycle efficiency by reducing cycle frequency and minimizing equipment impact. When the evaporator reaches the defrost cycle, the duct collapses, effectively sealing the unit and preventing heat from escaping. Water-repellant fabric prevents water droplets caused by the defrosting cycle from freezing on the fabric surface, further increasing the efficiency of a fabric-based solution.
Left: Arrows show how warm air leaves the air cooling unit when the system is in the defrost cycle
Right: Fabric duct covers the unit when the system is in the defrost cycle preventing heat from escaping the unit
Realizing Energy Efficiency Gains
Implementing solutions to increase cold storage efficiency can result in potential energy savings of up to 75% (contingent on equipment and operating conditions). The consequential reduction in defrosting time, ranging from 10% to 50%, results in heightened operational efficiency and diminished energy expenses.
Additionally, the use of fabric ducts not only limits heat loss but also improves air throw, fostering superior air mixing. This establishes a consistent and even temperature environment, ensuring the quality of stored goods.
Addressing frost-related challenges in cold storage facilities is not merely about resolving a surface issue but involves a strategic approach that significantly impacts energy consumption, operational costs, and the overall longevity of the facility’s components.
Additional Information
DefrostDuctTM increases the efficiency of cold storage air coolers
Fabric duct systems for food processing and cold storage
Sources:
https://www.energytrust.org/wp-content/uploads/2016/12/ind_fs_guide_coldstorage.pdf
FAQ
Frost on the evaporator surface impedes the conduction and distribution of cooling capacity, forcing the system to run more defrost cycles to compensate. According to the Energy Trust of Oregon, electric defrost can account for 21% of total energy usage in a cold storage facility.
Related terms: frost buildup, evaporator surface, defrost cycle, energy usage, refrigeration efficiency
A short fabric duct increases air throw and promotes air mixing for more uniform temperature distribution, which increases defrost cycle efficiency. When the evaporator enters a defrost cycle, the duct collapses and seals the unit, preventing heat from escaping.
Related terms: air throw, air mixing, defrost cycle efficiency, duct collapse mechanism, uniform temperature distribution
Water-repellent fabric prevents water droplets produced during the defrost cycle from freezing on the duct surface, which would otherwise reduce the fabric’s performance and shorten its service life over repeated freeze-thaw cycles.
Related terms: water-repellent fabric, freeze-thaw cycle, duct surface performance, service life, defrost cycle byproduct
Since electric defrost can represent up to 21% of a facility’s total energy usage, even a modest reduction in cycle frequency has a proportionally large effect on the overall energy bill.
Related terms: energy savings, defrost cycle frequency, operational cost, cold storage facility, refrigeration system efficiency
Learn more about temperature gradient control in cold-chain facilities in FabricAir blog article Enhancing Meat Processing Facilities with Fabric Duct for Optimal Temperature Gradients.
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