Liquid nitrogen or dry ice: which one to use for cooling
Nitrogen is colder, dry ice holds more cold per kilogram. A side-by-side table, the tasks each one is right for, and the safety difference people forget.
Both refrigerants work without a compressor and disappear by turning into gas. That is where the similarity ends: one is a liquid at −196 °C, the other a solid at −78.5 °C, and for most tasks the right choice is obvious once the numbers sit side by side.
The comparison in one table
| Parameter | Liquid nitrogen N₂ | Dry ice CO₂ |
|---|---|---|
| Temperature | −196 °C | −78.5 °C |
| Turns into gas by | boiling | sublimating, skipping the liquid |
| Cold from the phase change | ≈ 199 kJ/kg | ≈ 571 kJ/kg |
| Including warming the gas to 0 °C | ≈ 400 kJ/kg | ≈ 640 kJ/kg |
| Gas from 1 kg | ≈ 0.84 m³ | ≈ 0.54 m³ |
| Storage | Dewar flask, cryogenic cylinder, tank | insulated box, losses around 10% a day |
| Effect of the gas on people | displaces oxygen | displaces oxygen and affects breathing at a few percent |
The key point: dry ice carries roughly one and a half times more cold per kilogram, while nitrogen reaches a lower temperature. So for «keep it cold for a long time» ice wins, and for «freeze fast and very deep» nitrogen does.
When to choose liquid nitrogen
- Shock freezing food in tunnels and baths — freezing speed preserves the product structure.
- Cryogenic grinding of plastics, spices and rubber: the material turns brittle.
- Storing biological samples below −150 °C.
- Shrink fitting parts by cooling the shaft.
- Processes that also need an inert gas once the liquid evaporates.
When to choose dry ice
- Shipping chilled and frozen goods, pharmaceuticals and samples in insulated boxes.
- Catering and food delivery: the ice does not melt into water or soak the packaging.
- Cleaning equipment with a stream of pellets — dry ice blasting.
- Jobs without special containers: ice keeps in an insulated box, nitrogen only in a cryogenic vessel.
Dry ice pellets of 3, 16 and 19 mm are made in Ukraine by, among others, IceLab — from food-grade CO₂, with delivery across the country.
The safety difference
Both gases displace air in a closed room, but they behave differently. Nitrogen only replaces oxygen, and a person feels nothing until losing consciousness. CO₂ acts on the body itself: it speeds up breathing and causes headache and confusion at 3–5% in air, and it collects at floor level because it is heavier than air. Both need ventilation; CO₂ also needs detectors near the floor.
When you need a lot, all the time
Tunnel freezing or production-scale grinding counts nitrogen in tonnes a month — that calls for a liquid nitrogen tank, not cryogenic cylinders. How to store it and how much each vessel loses is covered in How to store liquid nitrogen.
Read nextHow to store liquid nitrogen and how long it keepsFrequently asked questions
Can dry ice and liquid nitrogen be used together?
Yes, and it is common in logistics: nitrogen for fast pre-freezing at the plant, dry ice to keep the product frozen in transit. What must not be done is to seal either of them in an airtight container.
Which is cheaper?
Compare the cost of the cold you actually use, not the price per kilogram. Dry ice delivers about one and a half times more cold per kilogram but costs more per kilogram than bulk nitrogen; the answer also depends on boil-off during storage and on whether you already have a cryogenic vessel.
You may also need
Cryogenic cylinders for liquid nitrogen (LIN, N₂)
Cryogenic cylinder for liquid nitrogen
Model: CC-N2
Portable vacuum-insulated cylinder for storing liquid nitrogen (LIN, N₂) with gas or liquid withdrawal. Volume, working pressure and configuration are selected for your process.
Price on request
On request
Cryogenic tanks for liquid nitrogen (LIN, N₂) 10–50 m³
Cryogenic tank for liquid nitrogen 30 m³
Model: CT-N2-30
Stationary vacuum-insulated cryogenic tank for storing liquid nitrogen (LIN, N₂), geometric volume 30 m³. Supplied with valves, pressure control, vaporizers and a pressure-reducing unit; turnkey installation available.
Price on request
Made to order
