Characterization of minienvironments in a cleanroom: Assessing energy performance and its implications

Filtered fans in cleanrooms can demand up to 400 W or more electric power per square meter of floor area to rapidly supply, recirculate, and exhaust air. “Minienvironments” that control particle concentrations within enclosures may not only maintain a level of stringent cleanliness, but also offer opportunities in energy savings and reducing operation costs through integration with adjacent cleanrooms. In order to better understand the total performance of minienvironments in operation, this paper characterizes energy performance of five different minienvironments (designated as ISO-Cleanliness-Class-3) that were in operation and were housed in a traditional, larger ISO-Cleanliness-Class-4 cleanroom used in the microelectronic industry. The measured parameters in the field investigation included electric power demand, airflows, in addition to physical characteristics and cleanliness performance of the minienvironments. In this paper, measured energy performance and associated metrics are compared to those of cleanrooms of various cleanliness classes. This paper develops new understanding of energy performance of minienvironments and quantifies the magnitudes of potential energy savings that could result from integrating minienvironments in traditional cleanrooms while achieving effective contamination control. Based upon this study, achieving energy savings by a magnitude of up to 60–86% was possible in the cleanroom facility housing the minienvironments. The paper also suggests means of increasing energy savings in minienvironments applications, including optimal design and operation, and space management in clean spaces.