Bjørn Falck Madsen explains how the new generation of compact ULT freezers means that scientists no longer need to fetch lab samples from remote storage areas
Imagine no longer having to leave your laboratory to walk the long distance to a remote storage facility to fetch a temperature-sensitive lab sample and risking that it spoils. With one of the new compact ultra low temperature (ULT) freezers, users can store any sample within arm’s length. These convenient high-performance cooling systems are designed to fit into small spaces, which means scientists can place the freezer in their laboratory, just a few steps away from their workstation. Not only does easy-access sample storage save a lot of time and inconvenience by allowing users to work uninterruptedly with their samples during the day, it also improves the safety of their valuable research material.
Ultra low temperature freezers promise low and stable temperatures
The smaller ULT freezers are particularly handy for storing diagnostic samples, reagents and vaccines in minor laboratories and offices. Covid-19 vaccines, for example, require a minimum temperature of -70°C or colder. With this new generation of compact freezers, a temperature of minus -80°C can be reached within three hours. In some of the ULT models, the temperature stability lies within a range of +/- 2°C .
A ULT freezer’s double-circuit cooling keeps the samples safe
As a practical feature, the new freezers come with two independent cooling circuits to provide optimal safety. In the unlikely event of an unexpected power failure or breakdown of one of the two cycles, the other cycle guarantees that the samples remain fully protected at a temperature of -70°C or lower. No matter what happens, the material will not be affected by any unexpected system failure but remain perfectly safe right until service is provided. For extra security, some models even come with the option of adding a CO2 backup system that injects CO2 in case the temperature inside the freezer rises above a preset level.
Ultra low temperature freezers are silent and highly efficient
Another advantage is that the new freezers deliver optimal performance under all conditions. Even with frequent opening of the door, the temperature returns to its desired setting within a very short time, thereby securing sample viability. The machines are surprisingly silent and extremely energy-efficient. Each shelf is individually cooled for improved temperature uniformity and because of the dual cooling system they have excellent pull-down and recovery times.
Optimal ergonomics with ULT freezers
The design ensures an ergonomically optimal unit that is both pleasant and easy to use. The compressor and other heat- and noise-generating components are placed on top of the freezing unit. This means that all compartments are easily and fully accessible, adding to their ergonomic value. It also means that the heat is distributed upward and backwards, thereby preventing the heat from warming up the entire room.
Bjørn Falck Madsen is an independent science journalist based in Denmark