A cryogenic tank is a double-walled, vacuum-insulated vessel that holds liquid nitrogen (LN₂) at –196 °C and keeps biological samples in or above it at cryogenic temperature for years. The vacuum between the inner and outer vessel cuts heat ingress so sharply that only a few litres of nitrogen boil off per day.
That makes the cryogenic tank the workhorse of every biobank, stem cell lab and GMP cell therapy facility. Understanding how it is built and what governs its hold time helps you store samples more safely, use less nitrogen and ask better questions when you buy.
Every life-science cryogenic tank works on the same principle as a vacuum flask, only across a temperature difference of more than 200 kelvin. Five components decide how well it performs:
Inside sits the storage inventory: racks, cassettes or boxes that give every sample a fixed position. How much a tank can really hold is covered in our guide to maximising cryogenic storage capacity.
Aluminium is light and mostly used for smaller, portable vessels. Stainless steel is more robust, easier to clean and the norm for large stationary storage tanks. Consarctic® builds in both: the aluminium ABV+ series from 4 to 150 litres, and the stainless steel ABS+, BSD+ and BSF+ series.
A cryogenic tank is passive. It does not refrigerate; it preserves the cold that the liquid nitrogen brings with it. The small amount of heat that still gets through the vacuum makes some nitrogen evaporate, the latent heat of vaporisation absorbs that energy, and the temperature inside stays stable for as long as there is enough liquid.
Two consequences follow. First, a liquid nitrogen tank needs no electricity to stay cold, which makes it far more fail-safe than a mechanical freezer. Second, it consumes nitrogen continuously, and that nitrogen has to be topped up, either by hand from a dewar or automatically through a supply line.
The key figure for any LN₂ tank is its static evaporation rate in litres per day, measured with the lid closed and no sample access. Together with the fill volume, it gives the theoretical hold time: how long the tank stays cold without a refill.
A worked example from the datasheet: the Consarctic® BSF420+ holds 464 litres and has a static evaporation rate of 8.3 litres per day. On paper, one fill lasts about eight weeks. In practice the reserve is smaller, because racks take up volume, every opening costs extra nitrogen and the level must never drop below a safe minimum.
Hold time is best read as a safety margin: it tells you how long you have if a delivery is missed or the auto-fill system fails.
Samples can sit directly in liquid nitrogen or in the vapour phase above it. In the liquid, every sample is reliably at –196 °C, but LN₂ can seep into imperfectly sealed containers and carry contaminants. Vapour-phase storage avoids that contact, at the cost of a vertical temperature gradient that needs to be controlled. Our comparison of vapour phase vs. liquid phase storage weighs both options.
Physically, both are vacuum-insulated vessels built on the principle James Dewar developed in the 1890s. In day-to-day lab language they differ by job: a dewar carries or dispenses liquid nitrogen, while a cryo tank stores samples long term in a defined position structure. For the different vessel types, see our article on cryogenic dewar containers and flasks.
Industrial bulk tanks for LNG, liquid oxygen or nitrogen supply are a different category again. They are pressure vessels holding thousands of litres and serve as a reservoir, not a sample store. Such a supply tank often stands outside the building and feeds the lab's storage tanks through a vacuum-jacketed line.
Wherever biological material has to stay unchanged for years, cryogenic storage tanks are the standard. Below roughly –135 °C, biological activity effectively stops, and storage in or above LN₂ covers that range reliably.
Which temperature suits which material, and when a tank beats an ultra-low freezer, is covered in ULT freezer vs. cryogenic tank.
A tank is only as safe as the system around it. Three things decide sample safety in daily operation:
Design matters too. The eccentric neck opening on Consarctic® tanks reduces the open area during access and cuts LN₂ consumption by up to 30 %, and a rotatable bottom brings each rack to the opening so samples spend less time outside the cold. More ways to save nitrogen are in reducing liquid nitrogen consumption.
A well-built stainless steel tank can serve 20 years or more. What usually ends its life is a slowly degrading vacuum, which shows up as rising nitrogen consumption long before temperatures suffer. Our article on cryogenic tank lifespan explains how to spot it and plan a replacement.
The right choice depends on sample format, volume, growth plans, floor space and the regulatory framework. For sizes, materials and options, see Consarctic® cryo tanks; the buying criteria are summarised in our guide to buying liquid nitrogen storage tanks.
Consarctic® is a market-leading German manufacturer of cryogenic systems for the life sciences, certified to EN ISO 13485 and ISO 9001, with more than 1,500 customers in over 30 countries. We deliver tanks, storage inventory, LN₂ supply and monitoring as one system, including IQ/OQ by certified technicians and a 24/7 emergency service.
Planning new storage capacity or replacing an ageing tank? Talk to our specialists about the setup that fits your samples.
A cryogenic tank holds liquid nitrogen in a vacuum-insulated, double-walled vessel. The little heat that leaks in evaporates some nitrogen, which keeps the temperature stable at down to –196 °C. The tank needs no power, only regular refilling.
It depends on fill volume and static evaporation. A tank holding 464 litres with 8.3 litres of boil-off per day lasts about eight weeks on paper. In service the margin is shorter, because racks take up volume and each opening costs nitrogen.
Both are vacuum-insulated vessels. In the lab, a dewar is mainly used to carry and dispense liquid nitrogen, while a cryogenic tank stores samples long term in fixed positions, with racks, monitoring and often automatic filling.
They store samples for biobanks, cell and gene therapy, stem cell and cord blood banks, pharmaceutical research and clinical trials, and reproductive medicine. In every case the goal is long-term stability below –135 °C.