Synopsis: Phase change materials (PCMs) have a large heat capacity，and it is easy to charge and discharge their heat because their temperatures remain constant during phase change．PCMs with variable phase change temperatures are used in many applications. The charging and discharging characteristics of the PCMs change depending on the temperature of the phase change and the quantity installed. It is necessary for the efficient use of PCMs to elucidate their charging and discharging characteristics via simulation. Previously, the authors proposed a model that can express the supercooling and its removal along with its calculation method. The specific enthalpy distribution of a PCM is calculated using the one- dimensional equation of thermal conduction, and the temperature distribution is calculated using T-h characteristics. Fairly good agreements were obtained between the calculated and experimental values of the cooling process. However, there was a slight difference in case of the heating process. In this study, to improve the calculation accuracy of the heating process, the melting of a PCM was modeled and introduced into the calculation. The calculation result can express the characteristics of the partial progress of the melting of the PCM near the heat transfer surface. Furthermore, it is possible to predict the state of change in the temperature and heat quantity of the PCM with high accuracy. Thus, the effectiveness of the calculation method was confirmed.

Because the frequency of repair and renewal of the air conditioning facilities is typically greater than that for the buildings in which these facilities are installed, air conditioning facilities require efficient maintenance. In this study, classification models using multi-layer neural networks that utilized the maintenance records of air conditioning heat source facilities were generated and evaluated. First, the failure histories and recorded values were organized and labeled as “failures.” Next, classification models were developed on the basis of an original multi-layer neural network. The generated classification models classified the training data well, and the boundaries of the classification corresponded to the changes in the recorded values identified during labeling. In the evaluation of the ROC curve and area under the curve (AUC), the AUC of most of the classification models was over 0.9, this is than that of the recorded values, thereby confirmed the high accuracy of the models.

To realize a simple and effective zoning environment in a general medical facility where no countermeasures against viral infections are taken, a zoning technology using two partition-type air purifiers with built-in HEPA filters was developed with reference to the performance and structural requirements of push-pull type ventilators. As a result of actual measurements of the wind velocity distribution between the air purifiers, it was confirmed that a maximum unidirectional airflow of 0.6 m/s to 0.8 m/s was formed on a given measurement surface. It was also demonstrated that the airflows on the measurement surface was drawn in by the suction-type air purifier and that the zoning technology could be constructed. Because some areas of stagnant air existed depending on the set airflow rate, the issue of airflow control necessary to improve the effectiveness of zoning technology was identified.

The purpose of this study is to update the water supply units (quantity) for the daily water supply load, which reflects recent water saving, as the basic unit for designing water and hot water supply systems. In addition, the water supply units that can be easily applied for each building application are indicated by clarifying the scope of the water usage. In our previous report, which is the first of its kind, we proposed a new water supply unit for general hospitals. In this study, we analyzed the water supply units for elementary, junior high, and high schools using a database, previous findings, and water usage calculation by application, and developed a new water supply unit for design. Furthermore, the ratio of portable to non-portable water, and scopes of water use which were not included in the new design units, were clarified.