JAES Learning

VISIT OUR YOUTUBE CHANNEL
Jaes Sponsor - Basket



Ultra-low-temperature freezers (ULT) Vaccine freezer

Ultra-low-temperature freezer or ULT freezer is one of the main tools used in many research laboratories, as well as in many branches of science such as: molecular biology and life science.
It also represent an essential device for vaccine transportation. An ULT freezer is in fact necessary when it comes to protect important and delicate biological samples.

These freezers are able to reach an incredible temperature of -86 degrees Celsius (or -123°Fahrenheit). Very low temperature when compared to standard refrigerators that come down to approximately -18°C (or 0° Fahrenheit).

For over a decade Jaes Company has been providing industrial spare parts and offers a wide selection of industrial freezers, refrigerators, refrigeration units and chillers from leading producers.

There are many types of ULT freezer and they come in different sizes.
The most common ones are: upright ULT freezers (which is also the most practical) and chest ULT freezers.

Let’s take a look at the characteristics:
ULT freezer capacity may vary and inside there can be drawers to store samples.
Each drawer is hermetically closed; in this way, when a sample is taken from a drawer, the other drawers can maintain their temperature.

Between inner and outer wall there is a polyurethane insulation, which is essential for an ULT freezer in order to maintain the temperature low.
The door has the same polyurethane insulation as well. Furthermore, a quadruple-step silicone seal provide perfect tightness.

In addition, ultra freezers are equipped with programmable logic controllers PLC that allow the control of freezing parameters.

Now let’s see how these refrigerators actually work. Here’s how the coolant flows:

High-pressure on coolant decreases by passing through the CAPILLARY TUBE. This simple action involves significant changes in the coolant: as a matter of fact, by reducing the pressure it lowers the temperature and therefore its BOILING POINT.
In this way the refrigerant can evaporate at a lower temperature.

This is possible thank to a thermodynamics phenomenon called JOULE-THOMSON EFFECT.
These new characteristics permit the coolant to absorb the heat in the refrigerator achieving the required temperature by passing through the EVAPORATOR.
The coolant now absorbs all the heat inside the freezer, lowering the temperature to the desired level. By absorbing the heat, it evaporates without changing its temperature.
Now the coolant passes through the COMPRESSOR, which raises the pressure to its initial value and raising consequently its temperature.
The next step is now to pass through the CONDENSER, that liberates the heat to the surroundings and converts vapour to liquid state so that temperature will reach a normal level.
This cycle is repeated. This is a perfect example of VAPOR-COMPRESSION REFRIGERATION CYCLE in
SINGLE-STAGE, which is very common in standard refrigerators and fridges.

A CASCADE REFRIGERATION CYCLE is a two-stage process, where there are two consecutive cooling circuits so that the 2nd stage lowers the temperature from the 1st in a continuous loop until the required level.

The low-temperature system (2nd stage) works exactly like the SINGLE-STAGE system we just saw, by releasing the heat using the evaporator; however, instead of a condenser the freezer is equipped with a HEAT EXCHANGER cooled down by coolant’s evaporation in the high-temperature system (during the 1st stage).
Eventually, the high-temperature system, that transports the full thermal input, transfers the heat to a condenser.

Basically, it’s like two SINGLE-STAGE systems were connected in a way that the evaporator of the first stage gets cooled by the condenser of the second one, facilitating the condensation of the compressed gas in the second circuit.

ULT freezers are essential pieces of equipment in many laboratories, especially those that require the safe and secure long-term frozen storage of materials such as vaccines, or temperature-sensitive biological samples like DNA, RNA, virus or proteins.

The main problem of ULT freezer is high energy consumption to achieve such low temperature.
This involves also the transport of temperature-sensitive biological samples and vaccines that need extremely cold temperatures to be efficacious.
That’s why scientists are designing a technology to create ULT freezers that can keep the temperature low even with no electricity, allowing to reach the most remote parts of the world.

If you find this video useful please let us know by leaving a comment and a thumbs up. You can also share it, and don’t forget to subscribe to our YouTube channel. Find out our next project on our website: jaescompany.com