We need to regularly defrost reefer containers after using them for some time. Much like their smaller refrigerator cousins, using reefer containers without occasionally defrosting them can cause many problems that degrade the containers’ performance.
Because of that, it is important to know how to defrost reefer containers to prevent problems that can happen from not defrosting them for a long time.
Challenges Related to Reefer Containers
These challenges often cause problems when someone needs to defrost reefer containers and clean them to keep their condition ideal.
Frost Accumulation
Frost buildup is one of the most common problems reefer containers encounter. When warm air from the outside enters the container or the interior is very humid, frost occurs.
A layer of frost forms on the evaporator coil as a result of the air’s moisture condensing and freezing due to the low temperatures. This ice accumulates over time and reduces the cooling system’s effectiveness.
In turn, the refrigeration unit must work harder to maintain the ideal temperature when the evaporator coil is covered in frost because it is unable to transfer heat effectively. This might result in increased energy usage and possibly a failure to keep the product at the proper temperature, which can cause spoiling.
Reduced Airflow
A buildup of frost not only damages the evaporator coil but also reduces the container’s internal airflow. As such, there must be a constant airflow to distribute the cold air inside reefer containers evenly.
Frost accumulation has the potential to impede airflow, resulting in heated areas inside the container. The uneven cooling process may result in unequal product quality because some areas may get excessively warm while others may freeze.
Increased Energy Consumption
As frost forms on the evaporator coil, the refrigeration unit needs to work harder to maintain the specified temperature.
This increased workload causes an increase in energy consumption, which, particularly on lengthy trips, can result in expensive fuel costs.
Excessive frost formation can force the refrigeration system to work constantly, increasing energy expenses and perhaps resulting in equipment failure.
Compressor Strain
The compressor in the reefer container’s system can suffer more stress when frost covers the evaporator coil.
For the refrigerant gas to absorb heat and keep the container cool, it must be compressed and circulated through the system by the compressor.
Should the accumulation of frost impede the coil’s ability to sufficiently absorb heat, the compressor can overwork and end up in early wear and possible malfunction.
Temperature Inconsistencies
Accurate temperature management is essential in reefer containers to maintain the cargo’s quality. Temperature variations brought on by frost accumulation can harm the cargo’s condition.
This can be especially harmful when shipping items sensitive to temperature, including medications or frozen meals, as even a little temperature change can cause substantial losses.
How to Defrost Reefer Containers (Carrier and Thermo King)
Many shipping container vendors like Tradecorp uses Carrier and Thermo King reefer machines in their reefer container lineups. As such, learn how to defrost reefer containers that use machines from these two brands.
Automatic Defrosting
Thermo King and Carrier reefer units both have automated defrost cycles. These cycles activate frequently, usually every 6 to 12 hours, depending on the operating environment and the amount of moisture in the container.
-
Temperature Monitoring
The reefer machine continuously monitors the evaporator coil’s temperature. The device initiates the defrost cycle when the temperature falls below a certain threshold because of the buildup of frost.
-
Heating Coils
The refrigeration system transitions from cooling to defrost mode during the defrost cycle, activating the heating coils contained in the evaporator coil. By gradually warming the coil, these heating coils dissolve any accumulated frost.
-
Water Drainage
Water does not build up inside the container because as the frost melts, the ensuing water drains via several pipes and is released from it.
-
Cooling Resumes
The refrigeration system starts cooling again to keep the container’s interior temperature at the predetermined level once the evaporator coil is clear of frost. The purpose of automatic defrosting cycles is to reduce cooling process disruptions and maintain the proper temperature of the cargo during the trip.
Manual Defrosting
Although most reefer containers can defrost automatically, there are times when manual defrosting is required, particularly in situations where frost buildup happens quickly or in significant quantities. The manual defrosting process in general goes like this:
-
Set the Unit to Manual Defrost Mode
A manual defrost button overrides the automatic defrost cycle on both Carrier and Thermo King devices. By pressing this button, the defrost cycle starts right away.
When operators see substantial frost buildup that the automatic cycle would not be able to remove, they frequently do this.
-
Monitor Defrost Progress
In order to melt the ice, the system will heat the evaporator coil when manual defrosting is turned on. Operators should monitor the unit’s defrost operation to ensure that it performs smoothly.
The defrost cycle’s progress is shown on the control panels of both Carrier and Thermo King appliances by the defrost status indicator.
-
Check for Blockages
Operators should look for any clogs in the drain lines while the system is defrosting. Water may freeze again and cause more issues if it can’t drain properly. A clear and functional drainage system should be checked.
-
Return to Normal Operation
Once the manual defrost cycle finishes, the machine will automatically return to cooling mode. Operators need to confirm that there is no frost on the evaporator coil and that the container’s temperature has returned to its original setting.
Additional Tips for Effective Defrosting
-
Frequent Monitoring
It is important to constantly check the reefer container to guarantee frost does not build up too much even with automated defrosting operations.
-
Avoid Opening the Doors Frequently
Limit the number of times the container doors are opened during loading and unloading to lessen the quantity of warm, humid air that enters the container.
-
Maintain Proper Air Circulation
Ensure that cargo is loaded correctly to give sufficient area for airflow to limit the possibility of frost buildup.
Conclusion
Knowing how to defrost reefer containers automatically and manually can keep these containers functioning for as long as possible. If you want some long-lasting reefer containers for your business, trust Tradecorp’s containers equipped with market-leading Carrier and Thermo King reefer machines. Simply fill out our quote form and we’ll provide the best reefer container solution for your business!