遠心形低温圧縮機を用いたヘリウム冷凍機
1985 年 20 巻 4 号 p. 224-229
詳細
1985 年 20 巻 4 号 p. 224-229
A helium refrigerator system equipped with low-temperature centrifugal compressors is proposed. This refrigerator, named L-system refrigerator, is operated almost below the temperature of liquid nitrogen. It has higher reliability and capability of long time continuous operation free from the contamination of helium with oil and from wear of moving part. It also has an advantage that the control of refrigeration power is easily achieved by adjusting the speed of compressors. The direct input power to the L-system refrigerator is lower, but it thermal efficiency is almost same as the conventional one, when the energy necessary to make liquid nitrogen is taken into account.
A L-system refrigerator with refrigeration power of 1, 500W at 20K level is designed based on the experimental results of the low-temperature centrifugal compressor developed at Electrotechnical Laboratory. Its refrigeration power at 20K varies from 930W to 2, 000W almost lineary by changing the rotational speed of the compressors from 500rps to 720rps. The direct input power is 17kW to 35kW, but it consumes 310kg to 630kg of liquid nitrogen par hour.
Large capacity helium refrigerators with high reliability and efficiency will be materialized when L-system refrigerators are built near the region where a large bulk of coolant is easily obtained, such as a LNG repository.
