vol.63-5 (2026/1/31)

System configuration and evolution of communication protocols in BAS

Building Automation Systems (BAS) serve as a fundamental technology for achieving energy conservation and operational efficiency in buildings. This paper outlines the functional hierarchy of BAS and the role of communication protocols. Additionally, it traces the technological evolution from proprietary standards to open systems, and presents a case study of a system implementation centered on cloud services and wireless technologies.

Potential application of BEMS to building environment and sanitation management

This study examines the applicability of Building Energy Management System (BEMS) data for building environment and sanitation management by validating their correspondence with small data loggers under different seasonal conditions. Two office buildings were selected, for which continuous measurements of temperature, relative humidity, and CO₂ concentration had been accumulated through both BEMS sensors installed in the occupied zone, on interior walls, and/or in return ducts, and small data loggers placed in the occupied zone during March-October 2024. The results show that (1) BEMS sensor readings of temperature, humidity, and CO₂ concentration are generally consistent with those measured by small data loggers in the occupied zone; (2) temperature and relative humidity show larger discrepancies between BEMS and small data loggers during the heating season, indicating that particular attention is required when using BEMS data in winter; and (3) CO₂ concentrations exhibit good correlations between BEMS and small data loggers across all seasons. These findings suggest the potential application of BEMS data for building environment and sanitation management.

Potential application of mall measuring instruments in building environments and sanitation management

This article examines the potential application of small measuring instruments in building environment and sanitation management by conducting: 1) long-term comparative measurements regarding automatic calibration of CO₂ concentration, 2) annual air environment assessments using small measuring instruments, and 3) an investigation into the feasibility of utilizing small measuring instruments for building environment and sanitation management. In summary, while the automatic calibration values for CO₂ concentration in small measuring instruments present challenges, they are considered capable of achieving measurements comparable to the current measurement method. However, compact measuring instruments face various issues, including individual variations and significant differences in results depending on the measurement location. Further investigation is planned to advance the utilization of small measuring instruments in building environment and sanitation management.

Accuracy management of CO₂ sensors
:Issues and countermeasures in digitally controlled ventilation systems

Reliable monitoring of CO₂ concentration is essential for balancing energy conservation and indoor air quality in digitally controlled ventilation systems. While Non-Dispersive Infrared (NDIR) sensors are widely adopted for this purpose, their accuracy is often compromised by environmental factors and the inherent limitations of Automatic Background Calibration (ABC) algorithms. This paper reviews the measurement principles of commercial CO₂ sensors and analyzes field malfunction cases based on interviews with manufacturers. It specifically examines the risks of measurement errors caused by ABC logic in continuously occupied spaces. Finally, ideal guidelines for accuracy management and sensor selection to ensure reliable HVAC operation are discussed.

AI image sensor-based multimodal sensing for active envelope control

This study investigates the use of AI-equipped image sensors to monitor environmental states around building openings. The sensor detects window positions, blind angles, brightness, view quality, and qualitative wind conditions through object recognition and image analysis. Experiments show high accuracy in identifying window and blind states and a strong correlation between image-based brightness and measured illuminance. The results indicate that image-based sensing can replace multiple physical sensors and support integrated, energy-efficient control of openings and shading systems. These capabilities enable integrated control strategies for natural ventilation, daylighting, and shading, contributing to energy-efficient and health-conscious building operation.

Smart air conditioning system using non-contact radiation thermal sensors

We are developing an air conditioning system that combines individual air conditioning by use of ceiling diffuser unit with built-in fan and a radiation sensor. The performance of this system was evaluated by thermal environment and questionnaire survey. The results of the survey in summertime were reported. It was confirmed that the newly introduced control method can maintain a high level of comfort even with little operation from the occupants.

Microwave science from its background to its application to environment, energy, biology, and food tech

This paper provides a systematic overview of microwaves, from fundamental theory to applied technology, highlighting their innovative potential in a wide range of fields, including environmental conservation, resource recycling, hydrogen energy, life sciences, and food tech. First, we summarize the principles and historical background of microwave heating and provide a scientific reexamination of conventional interpretations. In terms of applications, it introduces the decomposition of organic pollutants by promoting photocatalytic reactions, water purification using microwave-excited electrodeless lamps (MDELs), rapid decomposition of PFAS using in-liquid plasma, electronic waste recycling through microwave-induced pyrolysis, and hydrogen production using an organic hydride method utilizing selective heating. Furthermore, it discusses plant growth promotion and high-temperature-tolerant crop cultivation using non-thermal effects, as well as new developments in food tech through “intelligent microwave ovens” that combine semiconductor oscillators and IoT technology. These results suggest that microwaves are not merely a heating source but also an important technological foundation for realizing a sustainable society.

Leak test method for installed HEPA Filters

Pharmaceutical factories require HEPA filter leakage test for validation. In this paper, we first explain the outline of the leakage test method of HEPA filters indicated in the international standard (ISO14644-3) and then explain the leakage test method corresponding to actual field measurements. In addition, we proposed a simple and safe leakage test method for the current system, and we will explain this system.