July 29, 2016
Taiyo Nippon Sanso Corporation
Launch of large cooling capacity turbo refrigerator forhigh temperature superconducting power application(Product name: NeoKelvin®-Turbo 10kW)
Taiyo Nippon Sanso Corporation (President & CEO: Yujiro Ichihara) has announced
the commencement to promote large cooling capacity turbo-Brayton Note1)
refrigerator NeoKelvin®-Turbo 10kW that is possible to cool a superconducting
power application at -200ºC or lower by using neon gas as the working fluid.
1. Background of development
In the electricity related field, the research and development of electricity units(e.g. electricity transmission cables, fault current limiter Note2)) that uses
superconducting technology is driven as one of the solutions to establish resilientelectric grid. Among them, there is an expectation in the electricity transmission
cable area that there will be a huge demand for the overall cable system bydeveloping practical use going forward, and the amount of such demand isexpected to be 10-15 billion yen in 2030 in Japan alone. However, in order todevelop a practical application, it is necessary to have a refrigerator with thecooling capacity from 2kW to 10kW at the cooling temperature of around -200ºC.
Our company has developed a turbo-Brayton refrigerator (NeoKelvin®-Turbo2kW) with the cooling capability of 2kW by using neon gas as the working fluid as
the “Technological Development of Yttrium-based Superconducting Power
Equipment (2008 - 2012)” by New Energy and Industrial Technology
Development Organization (NEDO), and commercialized it in May, 2013.
NeoKelvin®-Turbo 2kW is capable to cool superconducting power cables with thelength of around several hundred meters as an experimental length. However, thecommercialization of NeoKelvin®-Turbo 10kW made it possible to coolsuperconducting power cables of more than 1km that is the length for acommercial use, and it is expected that the commercialization of superconducting
power cables will be accelerated.

1Currently, the prototype refrigerator is used to cool the cables to proof a concept
for superconducting power cables as a test jointly executed by Korea ElectricPower Corporation and LS Cable & System Ltd. at Jeju island (Korea), and theelectricity transmission to the actual system has started by using superconducting
power cables fromMarch thisyear. This electricity transmission bysuperconducting power cables with the turbo-Brayton refrigerator is the firstattempt in the world.
2. Feature of machineThis machine adopts neon gas as the working fluid similar to NeoKelvin®-Turbo
2kW to increase the efficiency of the turbo-machine. Feature of the machine isbelow.
1) We have adopted active magnetic bearings for the turbo-machine to compressand expand neon gas as it can be operated without mechanical contact by
floating the main shaft in the air to eliminate the maintenance.
2) We have developed a new turbo-machine which has the expander and thecompressor on the same shaft to recover the power generated at the expanderinto the compressor.
3) We have used a common structure for the two turbo machines necessary for therefrigerator to improve the economic aspects and convenience of the operation.
The above mentioned turbo machines were developed jointly with IHI Corporationthat have many experiences in turbo compressors for air separation plants among
others in order to realize high efficiency.
3. Specification of machine
Refrigeration temperature:

70K (-203ºC) (Temperature of liquid nitrogen at theoutlet of the refrigerator)

Refrigeration capability:

10kW (Cooling water temperature 20ºC, Substanceto cool: Liquid nitrogen with the circulation volumeof 0.6kg/s)

Power source voltage:

3-phase alternating current, 400V, 380V

Electricity consumption:

170kW

Cooing water:

750L/min2

4. Development going forward
We will expedite our activities to take orders mainly in Korea and United States as
they are aggressive to consider the introduction of superconducting electricity
transmission cables.
Note 1) Turbo-Brayton refrigerator
This is a refrigerator to generate cold by 4 processes ((1) Adiabatic compression,(2) Isobaric cooling, (3) Adiabatic expansion, (4) Isobaric heating). The neon gas
that is compressed by the turbo compressor ejects the compression heat to theatmosphere, then it is expanded under adiabatic condition by a turbo expander tolower the temperature of the neon gas. After that, it absorbs the surrounding heat,and it is returned to the inlet of the turbo compressor. In case of an actualrefrigerator, a heat exchanger is inserted between the turbo compressor and theturbo expander to collect the cold generated at the expander.
Note 2) Fault Current Limiter
This is on of the safety equipment to reduce the overload current swiftly ataccidents caused by short-circuit / electric leakage in the electricity transmission
and distribution system.

NeoKelvin®-Turbo 10kW

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