Ultralow temperature freezers (ULT) are a staple in laboratories and clinical operations. The freezer offers a temperature range between -40°C to -80° C. With the necessity for COVID-19 vaccine distribution they are now in the spotlight. The need for cold storage is a vital tool in our fight against the pandemic.

Most ULT freezers use a cascade refrigeration system, compared to a regular freezer with one compressor integration. ULT freezers use two compressors. This powers it to the lower temperatures found in a ULT.  There are two common ULT freezers, upright and chest freezers. One of the key features is its door seals that prevent the leaking of the temperature outside. ULT freezers also have walls made of polyurethane material that insulates the compartment.  

They play a definite contribution to cold chain storage. It is a piece of reliable equipment to store products and samples needing lower temperature requirements. It allows for an efficient operational process and quicker access to required samples. It is advantageous, especially for large-scale logistical distribution.  It ensures the safe transportation of biological samples. 

Specifically, ULT freezers can be used in 2 primary functions:

Crucial for research

A ULT freezer is an essential component of any laboratory science activity. Ensuring the safety and quality of specimens can be achieved through a low-temperature setting. Such temperature requirement is a need in pharmaceuticals, clinical facilities, and life science laboratories.

The most appropriate use of the ULT freezer currently is with biomedicine. The need for a cold storage facility in distributing mRNA-based COVID-19 vaccines all over the world is very high. Specific temperature requirements are a precondition for proper storage. ULT freezers can provide the range of storage temperatures needed for such operations.

Currently, Pfizer states that its vaccine can be stored at -70°C. A specialty freezer is required to last up to six months. Moderna, on the other hand, claims a more promising logistical intervention. The Moderna vaccine is kept at -20°C for up to six months. It can also withstand room temperature for 12 hours. These temperature range requirements can best be catered to by a ULT freezer.

Food supply

Low temperature goes beyond life sciences and clinical needs. In the food industry, specific low-temperature freezers are also a necessity. Restaurants and bars invest in ultralow temperature freezer to sustain their operations and provide a good dining experience to their customers. 

The food resource that needs such low-temperature storage is fish. Fish spoilage causes several problems such as protein impairment, dehydration, and even fat changes. What can address this? Slowing down the chemical processes through lower temperatures is the solution. Throughout Europe, fish resources should be stored at -30°C as recommended temperature point. At this temperature level, bacterial action is negated. Freezing is also a common way of preserving meat products. An increase in bacterial growth starts at 10°C. For optimal quality, meat has an ideal storage temperature of -2°C.

In less-developed countries, there is a necessity to store food. The food sources are tough to find and even access. Hence, cold storage is very advantageous.  Many of Africa’s arid regions have a long-term need for a storage facility for a food resource. Cold storage helps them attain quality food resources. The same is said with the issue of food wastage. Low-temperature freezers can reduce food spoilage. The cold chains are a sustainable solution to provide better food quality to underprivileged nations globally.

Why do we need to maintain a ULT freezer?

A ULT freezer is a significant investment. Not to mention it is just as costly to run. ULT freezers need proper maintenance. Making sure it runs in prime condition will avoid storage supply problems in the future. Adequate management of ULT freezers can extend this equipment’s service life, which will favor any of your storage supply problems.

There are certain maintenance checkpoints that one should look out for to ensure proper freezer operation. 

Maintenance key points:

Temperature control

Sometimes, in our hopes to get the prime conditions of our storage requirement, we set the temperature at its coldest point. The best approach is to check the manufacturer’s reference. Most ultralow temperature freezer can range up to -86°C. But storage samples also have a variety of temperature range needs. It may not need the maximum temperature range. Such is the challenge in storing samples. It is unnecessary to go full-blast on temperature as it will depend on the current storage need. A good practice is to keep the temperature within control ranges per the recommendation of the manufacturer. You can also ask for advice from service technicians on what is the best temperature setting. 

Photo Credit: www.www.eppendorf.com


ULT Freezer’s normal operating dynamics is it gets air in the front and exhausts it in the back. An adequate clearance at the end of the freezer is recommended. A small space will create a vacuum where air cannot circulate well, which will lead to further problems. Moreover, sufficient space in front is also required to make way for the air being taken in by the compressor. 

Power Supply

Making sure that the freezer is used with a stable power supply is a must. If the freezer location has constant power failure or outage, this may not be good for the freezer’s life span. In case it cannot be avoided, backup power options should be made available. The correct power voltage that is needed by the compressor should also be used.

Steps in maintaining ULT freezer’s good-running form


Regular defrosting should be followed. The accumulation of frost in the freezer is caused by water vapors getting in contact with the equipment’s cold walls. In the long run, the frost build-up can obstruct cold temperatures that are detrimental to the freezer’s temperature range capacity.

While there is no concrete advice on defrosting, regular defrosting activity can help the freezer maintain its temperature condition. Defrosting once a year is recommended. However, it is best to defrost depending on the level of use. A good indicator when it is time to do so is when you see a build-up of frost in your compartments. 

Remove the dust

Like most freezers, a condenser is a fundamental unit of its running capability. A condenser is a device that changes heat into liquid form through the cooling process. In a freezer setting, a condenser takes heat that is formed inside the freezer and brings it outside. 

A condenser is made of filters. The filter collects dirt through the process of extracting heat. When grimes and dust gather too much in a filter, it lessens its capacity to remove heat. If dirt accumulation is too much in the filter, the condenser will compensate for changing more heat into liquid form, expanding its ability to exert more energy. Regular cleaning of the condenser every three months is advised.

Proper sample storage

While it is true that ultralow temperature freezers are equipped to provide lower temperature storage, filling it beyond its capacity is not good. It is best to avoid storing samples on the upper part of the freezer to allow better air circulation. The holding of warm samples should also be avoided because it exhausts the mechanical capacity of the freezer. 

Proper storage of vaccines
Photo Credit: storage covid vaccines


Despite regular maintenance of ULT freezers, one can overlook the checkpoints needed for it to run in prime condition. Innovation in sensor monitoring has addressed such bad operational practices. The likes of Ultra Cold temperature sensors can monitor wide temperature ranges, especially in logistical circumstances. Wireless sensors can help detect a power outage and the absence of AC voltage.  

There are also monitoring systems that can provide real-time feedback and analysis. In ULT storage, a freezer equipped with a monitoring system can provide historical data logs and automated checks. Such devices can pinpoint temperature deviations or problems with the electrical system. A wireless monitoring device can also send status reports, especially human errors. So, when the freezer doors are left open or equipment problems, an alert notification can urgently address the issue. 

There is a wide range of ULT freezers in the market right now. Each is fitted to specific temperature and storage demands. The decision to get this kind of equipment requires high costs, proper handling, and the right intended use. The benefits gained from it is essential. Much more now with the advent of the COVID pandemic. But more than that, long-term benefits should be maximized from ULT freezers. This can only be achieved through proper maintenance and observance of the necessary care it needs.










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