vol.62-1 (2024/5/31)

Construction of an energy-efficient cleanroom using a swirling-induction-type stratified air conditioning system

There is growing demand to reduce the costs of quality maintenance and production in production plants. Reducing the energy consumption within large-space cleanrooms presents a particularly significant challenge.
In this study, we applied a swirling-induction-type stratified air conditioning system (SWIT), which could efficiently cool and filter the air in a large-space cleanroom while preserving the manufacturing environment and conserving energy. This report provides a basic technical explanation of the use of Takasago Cleanroom SWIT (TCR-SWIT) systems in cleanrooms and the construction of a comprehensive energy-efficient air conditioning system through the combination of various energy-saving technologies achieved by introducing TCR-SWIT.
The energy-saving potential of SWIT systems is widely recognized, and they are currently used by many customers. In addition, the “SWIT System Energy Efficiency Renewal Project” won the 2012 Energy Efficiency Grand Prize (Product and Business Model Category).
TCR-SWIT systems have achieved record sales since 2006 and demonstrated extremely high energy-saving potential at low costs. Therefore, these systems are expected to achieve significant results in the field of cleanroom air conditioning and become the standard for the next generation of cleanroom air conditioning systems.

Cleanroom air conditioning system using downflow and upflow

In the cleanroom, there are an operation area that requires high cleanliness and a maintenance area where the main production equipment is installed, and each area requires different air conditions. Therefore, we have developed “DOUP” air-conditioning system, composed of downflow in operation area and upflow in maintenance area. We have verified the performance of this developed air-conditioning system and the conventional ballroom air-conditioning system and confirmed this developed air-conditioning system is an effective air conditioning system. In addition, we built and validated a CFD analysis model.

Upflow and ceiling supply and return cleanrooms

Optimizing airflow patterns is important for energy conservation in cleanrooms. The airflow patterns are strongly influenced by air supply and return configurations. This study experimentally compares five airflow types: downflow, filter unit upflow, fan filter unit upflow, displacement ventilation, and ceiling supply and return. In the downflow type, air is introduced through ceiling fan filter units and returned through perforated raised floor panels. In the filter unit upflow type, air is supplied through perforated raised floor panels and returned through perforated ceiling panels. In the fan filter unit upflow type, air is supplied by underfloor fan filter units and returned through perforated ceiling panels. The experiments involve three different indoor heat loads, and the number of air changes per hour varies from 17 to 106. As there are few particles larger than 5 μm, no significant differences are identified in the experiments for particles of this size. However, for particles larger than 0.3μm at 1.1m above the floor, the concentrations of particles are consistently lower in the upflow and ceiling supply and return types compared to the downflow type under all experimental conditions. Furthermore, the fan filter unit upflow type has the lowest concentration.

Energy-saving technology for clean air conditioning system using environmental sensors and its application

An energy-saving control system for cleanroom air conditioning has been developed. The system controls cleanroom air conditioning based on information obtained by an image-type motion sensor and a small particle sensor that can monitor the cleanroom conditions and environment. This paper comprehensively introduces a series of process that we have made to develop the control system and install it to some actual cleanrooms. Specifically, the background and contents of the development, the basic experiments to investigate the characteristics of the sensors and performances of the control system, examples of installations to some actual cleanroom, and operational results are described. In addition, as examples of utilization of data accumulated by the control system, an AI learning system and a technology for estimating particle emission sources are reported.

Mass production of nanofibers and application to air filters

It has been known that nanofibers exhibit excellent performance as filters. However, due to low productivity, it was only used for very special purposes such as tank engine pre-filters. We developed the Zetta Spinning (Zs) method to solve the problem of low productivity in nanofiber manufacturing. Currently, production of over 40 kg/hour is possible. Since the Zs method can be applied to both thermoplastic and solvent-soluble polymers, it is possible to make nanofibers from not only PP and PE but also many other polymers such as PET, PLA, and PES. Furthermore, since there is a fiber diameter distribution, it is possible to create functionality with thin fibers and maintain strength with thick fibers. For these reasons, it is thought that various applications will be developed in the field of air filters in the future.

Basic of BCR

BCR, biological cleanroom has been used for Medical, Pharmaceutical company and hospital to protect final product and human etc. from microorganism. Basic construction is similar as ICR (Industrial clean room) but the key different points are the purpose and management way for each clean room. This time I would like to explain the basic and important topics including the management for BCR.