Consider the implications of preserving a sample in a ULT freezer that belongs to an individual who is no longer available, or managing samples collected from diverse global regions where replacement may be difficult or excessively costly. This underscores the critical importance of sample / specimen preservation, and perhaps no piece of laboratory equipment is more important to sample preservation than a ULT freezer.
We have already discussed Backup Systems for ULT Freezers and how they can serve as a reliable safeguard when unexpected issues arise. These backup systems provide an extra layer of security, ensuring that valuable samples and research materials are protected even in the event of a power failure or technical malfunction. Although we can rely on these backup systems, unforeseen issues can arise beyond anyone's control. It is also crucial to treat our ULT Freezers with care, as they represent a significant investment for your laboratory.
Proper maintenance and regular checks can extend the lifespan of these essential laboratory appliances. In preserving critical research samples or medical specimens, ULT freezers are one of our best friends, and we want to keep them in optimal condition.
The energy efficiency of ULT freezers is primarily determined by the duty cycles of the compressor (the percentage of time the compressor is running) and the associated energy pull. Under typical field operation, duty cycles are driven by cooling demands and vary between 31% and 88% depending on the freezer´s design, temperature set point, and use. Factors like air leaks or blocked airflow can increase strain on the system. The aim is to minimize cycles to extend the unit's lifespan while maximizing energy efficiency.1
While ULT freezers are low on maintenance, there are essential operational tips and tricks to keep in mind to ensure they run at their best!
When Installing:
- First, ensure the unit is installed on a level surface, free from any rollings or angles.
- Maintain a minimum of 5 inches of space between units, at least 8 inches at the top for adequate ventilation, and 5 inches at the back. Avoid stacking items on top of the unit to ensure proper airflow around it. (Some ULT freezers may specify different clearance requirements in their manual due to having differently engineered ventilation systems. Always listen to your manual over any general guidelines.)
- From an electrical perspective, confirm that the units are connected to a dedicated circuit, meaning they should not share power with any other equipment. Shared circuits may have fluctuations in electricity which are detrimental to a freezer’s performance and health. It is essential to verify that the line voltage and capacity are appropriate as shown in the unit´s manual.
- Additionally, consider room temperature during the installation of a ULT freezer; the specified temperature range is generally between 15°C and 32°C, but check your manual for your specific ULT’s permissible operating conditions.
Spaces to consider when purchasing a ULT Freezer.2
Daily use:
- To optimize daily use of the unit, it is crucial to minimize both the frequency and duration of door openings. Opening the door allows cold air to escape and warm, moist air to enter, which requires additional cooling. The longer the door remains open, the more air exchange occurs. Repeated door openings within a short period of time causes a spike in the temperature and energy pull. Frequent door openings also make your ULT freezer work harder, reducing its life span. Even modest use pulls 10 percent more energy than during off-hours.3
- When retrieving samples it is very important to only open one inner door at a time to minimize that air transfer, make sure you have thought about what sample you are going to retrieve, know where it is located, retrieve it quickly, then promptly close the doors.
- When loading large quantities of warm samples into the freezer, it is best to pre cool them whenever possible. Additionally, try to limit the volume of warm samples loaded at once. Ideally, load one shelf at a time, let it reach the setpoint temperature, and then proceed to load the next shelf. These freezers are meant for maintaining temperature, not for rapidly cooling large quantities of samples. Avoid overloading them with warm products.
Regular Maintenance:
It is important to keep the filter clean. If the filter fills with dirt, it can shock the unit and prevent proper airflow, leading to heat buildup and premature wear. The filter can be removed, vacuumed, or cleaned with soap and water, and it should be allowed to dry thoroughly before being replaced. Additionally, check the condenser for dirt buildup, which can be easily vacuumed out. Another important maintenance task for the ULT freezer is to inspect the integrity of the seals and ensure there is no ice accumulation around the perimeter. If ice is present, remove it with a scraper, taking care not to damage the seal. Also, examine the unit's perimeter and remove any built up ice, as issues with the seal can allow air to leak in. Overall, keeping both the filter and seals in good condition is essential for the optimal performance of the unit.
As all ULT freezers are manual defrost, it will require periodic ice removal, as buildup can insulate the walls and hinder performance. To defrost, transfer samples to another unit, turn off the freezer, allow it to warm up and dry out, then cool it for about 12 hours before returning the samples. This process is recommended to be performed at least once per year.
Keeping organized is absolutely critical when using a ULT freezer. Minimizing the time spent with the door open and reducing inefficiencies is essential. Utilizing tools like boxes and racks, such as sliding drawer racks, is highly recommended. Barcoded tubes can help quickly locate and identify samples, while barcode readers further reduce the time needed to access samples. By minimizing access time, we can decrease frost and ice buildup, reduce maintenance needs, and ultimately ensure a more efficient and reliable freezer.
SST Storage Drawers for Ai G04h -86C Freezers 6,000 Vials Max.
Operational hints to keep in mind
- A full freezer is a happy freezer: To maintain efficiency, keep your freezer as full as possible. This helps to keep the items inside colder as it reduces air displacement when the door opens, which helps minimize frost buildup and air exchange.
- Regularly assess your samples: If you have any that are no longer needed, remove them to free up space. This will help you realize maximum value from your ULTs.
- Establish a retirement and replacement program: the worst case scenario is facing an emergency that jeopardizes your samples, requiring you to replace equipment swiftly. Consider the total cost of ownership; older units consume more energy, demand frequent repairs, and may have obsolete parts. By implementing a planned replacement program, you can simplify your operations over time. Take full advantage of promotions, trade in initiatives, and standardization programs to manage your fleet more efficiently.
- Establish a plan to safeguard your samples: To effectively protect your samples, it is crucial to have a disaster recovery plan that includes monitoring systems, backup systems, and additional units for relocating samples if necessary.
Added CO2 Backup System for Ai -86C ULT Ultra-Low Freezers.
Remember: Keep in mind that a little prevention goes a long way. It leads to longer lasting equipment, fewer service problems, improved energy efficiency, cost savings, and ultimately, peace of mind regarding sample security.
In the PDF attached below, you can find a printable checklist to help you organize and simplify your ULT freezer´s maintenance.
Maintenance for ULT Freezers checklist.
References:
1. https://www.etcc-ca.com/reports/ultra-low-temperature-freezers-opening-door-energy-savings-laboratories?dl=1575839418
2. https://www.news-medical.net/Life-Science-and-Laboratory
3. https://f.hubspotusercontent40.net/hubfs/547446/43685_LM_Liebherr_Digital-Article_JL-4.pdf
