Using Air as a Refrigerant

By Tine Stausholm, Sep 26, 2019, 11:51 1 minute reading

Coolinn is launching a cryogenic sauna that uses Mirai’s COLD air-cycle technology to achieve -110°C (-166°F) temperatures.

Mirai COLD units use only air as a refrigerant to achieve very low temperatures.

On October 12, German cryotherapy operator Coolinn will introduce its first cryogenic sauna with air-cycle refrigeration unit, which boasts lower power consumption and reduced maintenance costs as compared to similar cascade vapor compression systems.

A cryogenic sauna is essentially a reverse sauna − a very cold room without the humidity of a conventional sauna. Cryogenic saunas are used by athletes for “cryotherapy,” which can improve physical performance and aid recovery from injury. It can also be helpful in treating certain diseases like rheumatism, fibromyalgia and inflammatory ailments, according to Coolinn’s website.  

The refrigeration technology driving the new cryogenic sauna, called Mirai COLD, is provided by European engineering and manufacturing company Mirai Intex. Founded in 2015, Mirai presented its first Mirai COLD unit at the Chillventa exhibition in Nuremberg, Germany in 2016.

Mirai COLD units use only air as a refrigerant to achieve very low temperatures, down to -130°C (-202°F), in a one-stage system. Traditional low-temperature systems typically use three-stage cascade systems charged with R404A, R23 and R14 – all of which have extremely high GWPs of 3,922, 14,800 and 5,700, respectively.

Mirai COLD currently comes in three different versions, with power capacities of 10kW, 15kW, and 22kW respectively. A new model, called the Mirai Cryo, uses nitrogen instead of air and can achieve temperatures as low as -160°C (-256°F). Mirai Cryo is not commercially available yet, however pre-orders can already be placed.

Mirai is not the only company developing air-cycle low-temperature technology. Japanese manufacturers Mayekawa and Mitsubishi have also developed air-cycle machines, mainly for rapid freezing of tuna.

Read this article in its entirety in the October 2019 issue of Accelerate Magazine

By Tine Stausholm (@TStausholm)

Sep 26, 2019, 11:51

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