A new range of cold groups uses ambient air as a refrigerant

Mirai Intex conçoit et fabrique des machines utilisant l’air ambiant comme fluide et capables de descendre à de très basses températures négatives : de -40 à -130°C

Created in Switzerland in 2015, installed in Vienna in Austria and Brno in the Czech Republic, Mirai Intex is a company specializing in the design, development and manufacture of cooling solutions at very low temperature, with a minimal environmental footprint.

In 2016 at the Chillventa show in Nuremberg, she had exhibited her first Mirai Cold machine.These systems use ambient air as a refrigerant.

Air or R279 in the Ashrae nomenclature of refrigeration fluids

Air - also known as R729 - has excellent thermodynamic qualities.Equipment producing cold at very low negative temperatures classifies a triple cascade of R404A, R23 and R14.These three fluids display GWP (Global Warming Power or Contribution to the warming of the atmosphere) particularly high: 3922 for the R404A, 14,800 for the R23 and 5700 for the R14.

These three fluids are naturally targeted by the European F-Gaz regulation.And it was urgent to find another solution.The company offers a whole range of machines capable of going down to -130 ° C and using air (zero gwp) as a refrigerant.

She is not the only one to embark on this technology.The Japanese Mayakawa and Mitsubishi Heavy Industries have also developed systems based on an air cycle for quick freezing.Mirai Cold machines are stamped CE and available in France.

A technology invented 100 years ago

This technology was invented about 100 years ago.The air cycle, but also refrigeration technologies with nitrogen cycle, are used in factories to obtain cryogenic cold, to liquefy natural gas, as well as in air conditioning systems.

Everything is based on air properties: its temperature increases when it is compressed and decreases when it is relaxed.The repetition of compression and relaxation cycles allows you to descend the air temperature to -160 ° C.

As Mirai Intex implements it, air cycle technology leads to machines operating without oil, without any chemical fluid, with little vibration and noise, capable of deliver a precise temperature at 0.5 ° Cnear, with a real -time and extremely reliable monitoring system over time.

The compressor/regulator is the heart of technology

The heart of the technology is the turbo module, a centrifugal air compressor/.The compressor and the regulator are mounted on the same tree driven by a single electric motor.The compressor recovers part of the energy produced by the regulator.Which reduces energy consumption by 30% compared to a system with two machines (compressor and regulator) separated.© MIRAI INTEX

Mirai Intex designs and manufactures the wheels of the compressor and the regulator himself and adjusts them according to the desired temperature regime.© MIRAI INTEX

This air cycle technology produces heat and cold.The heat can be recovered to produce ECS, heating, for a drying process, etc..The temperature difference on both sides of the tree can reach 300 ° C.© MIRAI INTEX

Finally, the compressor avoids the use of oil by using air bearings.When the tree is speeding, it is held in place by the compressed air cushion.

Open or closed refrigeration cycle?

Mirai Cold machines are either open loop or closed loop.In the case of an open cycle machine, ultra-cold air is introduced directly into a cold room (or any other form of well-insulated refrigerated space).

Typical refrigerants only work in closed circuits, and refrigerant leaks are one of the problems in the refrigeration system itself.To avoid environmental damage caused by refrigerant leaks, the F-Gaz regulation particularly insists on the verification of the waterproofing of the refrigerant circuits.None of this applies when the air is used as a refrigerant.

The air is introduced directly into the refrigerated space, without evaporators or auxiliary fans in the room.At extremely low temperatures, humidity instantly turns into ice and the air circulating in the system must therefore be free of ice.The company has developed a humidity elimination device.It eliminates all humidity inside the refrigerated space and mechanically extract in the form of snow.

This dehumidifier works automatically and therefore deletes the need for defrosting procedures, offering the most stable conditions for long -term storage.

A closed cycle machine, on the other hand, has an air/other fluid interchange.The air circulates in closed loop in the cooler.The company recommends silicone oil as a secondary fluid.A closed cycle requires an air supply under a pressure of 6 to 8 bar.

The Mirai Cold 80 T (MC 80 C/W/T) reaches a cooling capacity of 53 kW with an electrical power of 80 kW, or a COP of 0.66.Mirai Cold 80 T (MC 80 C/W/T) grows up to a cooling capacity of 53 kW with an electrical power of 80 kW, or a COP of 0.66.© GENERAL INTEX

Seven Mirai Cold machines available

The company manufactures seven different machines:

In the cryogenic cold, at -100 ° C, for example, a COP of 0.6 is impressive.

All machines have an on -board regulator and can communicate in Protocols Profinet, Ethercat, PowerLink and Ethernet/IP.© MIRAI INTEX

What jobs for Mirai Cold machines?

Open cycle machines applications are used for organic or pharmaceutical storage, meat and fish storage and cryotherapy rooms.While closed cycle machines are rather adapted to liquefaction of all kinds of gas, egging and lyophilization processes.Closed cycle coolers can be easily adapted to existing mesing facilities and new installations.

The main jobs of Mirai Cold are currently in industry.But heat recovery offers perspectives in canteens (cold rooms and simultaneous DHW needs) and restaurants.© MIRAI INTEX

Coolinn, a German cryotherapy operator, has developed "cryogenic saunas" using Mirai Cold 10 T machines.He believes that, compared to a cascade of multiple fluids, maintenance is reduced and energy consumption is lower.A cryogenic sauna is quite exactly the opposite of a sauna: a very cold and dry room.Cryogenic saunas are used in cryotherapy by athletes to increase their performance or accelerate their recovery after injuries, but also in the treatment of rheumatism and inflammation.© MIRAI INTEX

Source: Batirama.Com / Pascal Poggi