省エネ・省資源を実現するクリーン空調システムの開発(その3)
T&Aシステムの課題である堆積塵の再飛散、モータ発塵、設備機器の低騒音化について検討を行った。歩行による再飛散は堆積塵量の20~40%で気中濃度への影響は少ない。また、気流による再飛散は風速2m/sで開始され、T&A方式CRの気流(0.8m/s以下)では再飛散しない。モータからの発塵量は作業者の発塵量と比較して桁違いに少なく、対策により更に低減できる。騒音については、FCU・FFUの機器単体で10dB以上低減し、部屋全体で15dBの低減となった。
Development of an Energy and Resource-saving-Air Cleaning System (part 3)
In this paper, particle generation, reentrainment of deposited particles and noise of equipment are examined. The amount of reentrainment of particles from walking is 20 to 40% of the amount of deposited particles, and there is little influence of the particle concentration on reentrainment. Moreover, it was clarified that the deposited particles disperse at an air velocity of about 2.0 m/sec or more, and the particles hardly re-disperse under the influence of air velocity (0.8 m/sec) in a T&A system cleanroom. The amount of generated particles from an electric motor is less than the amount of generated particles of worker's. The amount of generated particles decreases by less than one tenth by means of closing an opening of an electric cord and adding a small chamber through the shaft above the motor case. The noise value of FCU-FFU has been reduced by 10dB or more and the noise value of the room has been reduced by 15dB.