vol.62-3 (2024/9/30)

Energy conservation for buildings

In this paper, the energy saving standard shown in the Law about energy consumption performance gain of building is mainly explained, and the future trend of BEI is also described. BEI is an abbreviation for Building Energy Index. It is obtained by dividing the design primary energy consumption of a building by the standard primary energy consumption, and is a representative indicator of energy saving standards. Next, after clarifying the definition of quantitative ZEB (Zero Energy Building), the knowledge required to understand it correctly is listed. It is important what kind of society we aim to build in the future by promoting energy saving in buildings. Society5.0 and smart city of the Cabinet Office are presented.

Human factors aiming at indoor environmental comfort and energy conservation

Sensors such as thermometers and hygrometers and CO₂ concentration meters are installed at representative points in the room, and the air conditioning and ventilation equipment are controlled so that the sensor readings are within the comfortable range. In order to ensure indoor comfort, the general air conditioning control is to sufficiently mix the indoor air flow so that workers can be comfortable wherever they are in the room. However, it is not necessary to uniform air condition in the room except the living area, and in some cases this can lead to air conditioning in unnecessary spaces, which often leads to energy waste. In addition, whether or not a person feels comfortable and therefore can demonstrate high productivity depends on the local environment around the person to which the person actually staying in the room is exposed, so it is important to change the control concept from “environmental control for the space” to “environmental control for people”.

Development and demonstration of air conditioning system for gymnasiums

In recent years, an air conditioning and ventilation system for gymnasiums that covers heat stroke prevention due to global warming and infection prevention when used as a disaster shelter has become important. Therefore, in this study, a heating and cooling air conditioning and ventilation system has been developed and demonstrated at the Fujimigaoka Elementary School gymnasium in Tsukubamirai City. The system consists of an all-outdoor air operation type air-cooled heat pump outdoor unit and a vinyl balloon-type diffuser, which efficiently provides heating, cooling, dehumidification, and ventilation without affecting athletic performance. This report describes the results of the demonstration in FY2022～2023.

Infectious disease prevention and energy conservation in air conditioning

Air conditioning with high-efficiency air filters is known to be effective in preventing infectious diseases caused by aerosols. On the other hand, the use of an air filter with high collection efficiency raises the issue of increased energy consumption due to increased pressure loss. In this study, we examined filter selection guidelines in consideration of infectious disease control and energy conservation in an actual office building, and measured changes in CO₂ concentration and particulate concentration in the room equipped with air filters of three different collection efficiencies (JIS-65%, 90%, and 98%) during air conditioning operation. The results showed that there was a marked decrease in particle concentration in the JIS-98% air filter. Based on these experimental results, changes in particulate concentration due to ventilation in the test room were estimated by a perfect mixing model. Furthermore, the relationship between energy consumption of air conditioning and infection risk reduction was clarified by calculating the infection rate reduction effect using a simple infection risk model. As a result, guidelines for optimal air conditioning selection considering energy conservation were obtained.

Latest trends in air filters that contribute to energy conservation

Air filters are used not only in building and industrial air conditioning systems but also for volcanic ash protection and deodorization purposes. Energy efficiency during filter use, resource conservation during disposal, and reduced environmental impact during transportation are always sought-after factors. This paper introduces the latest trends in these areas.

Automatic energy saving control system with clean monitor and visualization of clean room

We have developed an energy saving control method to reduce airflow volume while maintaining cleanliness by using a cleanliness monitoring system that automatically adjusts airflow volume. We also report on a system that visualizes conditions in a clean room using a measurement unit that incorporates a temperature/humidity sensor into a clean monitor.

The changing perspectives on transmission modes of respiratory infections and their context

On 18 April 2024, WHO published the “Global technical consultation report on proposed terminology for pathogens that transmit through the air”. The report moves away from the two traditional dualisms of pathogen particle size (5 μm) and the transmission range of pathogen particles ≥ 5 μm (1-2m). It proposes new terminology for the transmission mode of pathogen particles that includes airborne transmission/inhalation and indirect contact at any distance, as well as direct deposition and direct contact at short distances. This review looks back at the history and evolution of views on the transmission modes of respiratory infections and their background, and provides an overview of the contents of the WHO report.

Facility for regenerative medicine

Because regenerative medicine uses living cells, it is manufactured in a clean environment called a cell processing facility. However, because automation of manufacturing is still difficult, cells are prepared directly by humans. Furthermore, since the product cannot be sterilized, very strict sanitation management is required. Therefore, we will introduce the requirements and points of attention for cell processing facility.