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The characteristics of various types of refrigerator noise were investigated in an anechoic chamber and in a real living environment - a 100 m2 apartment which is a common size in Korea. It was found that the sound pressure level of the refrigerator noise in the real living room was about 10 dB higher than the level in the anechoic chamber at the same position (1 m in front of refrigerator). In addition, a tolerance level for refrigerator noise was determined by subjective evaluation experiments. Refrigerator noise was presented by a loudspeaker placed in the kitchen where the refrigerator is normally located. Level 2 responses to the subjective evaluation (“hardly perceivable”) corresponded to a sound pressure level of about 26 dB(A), for which 90% of participants were satisfied with the level of refrigerator noise. A semantic differential test using various adjectives was also conducted to evaluate the sound quality of refrigerator noise. With the semantic differential and the factor analysis, adjectives used in this experiment were grouped into three factors. From the results of correlation and multiple regression analyses on the psychoacoustical parameters and subjective evaluations of 30 kinds of refrigerators, sound quality index which predict the subjective rating score were proposed. 相似文献
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介绍了带LN2预冷的二级膨胀循环的流程计算方法,并提出了优化计算的思路和计算机程序实现的方法;最后就换热器热端温差对制冷机效率的影响进行了讨论 相似文献
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随着超导技术和制冷技术的相互促进和共同发展 ,制冷机直接冷却的超导磁体系统已从概念设计走向实际应用。电流源保护控制系统是超导磁体系统的重要组成部分 ,其主要作用是为超导磁体系统提供稳定电流并实现可靠的保护控制。文中首先分析了制冷机冷却型超导磁体系统用电流源的工作过程及其特殊的控制和保护要求 ,然后设计了一个以单片机为核心的自动保护控制系统。 相似文献
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