Prediction of the long-term performance of vacuum insulation panel installed in real building environments

Vacuum insulation panels (VIPs) are high-performance insulating materials constructed by covering a core and adsorbent with an envelope and evacuating the air from the inside. VIPs have used to enhance the energy efficiency of devices including refrigerators, vending machines, and cooler boxes. In order to apply VIPs as heat-insulation materials in buildings and houses, it is necessary to predict the long-term performance of the VIPs and verify the accuracy of the prediction using actual measurements. VIPs using glass fiber as a core material are spreading in Japan, and VIPs using glass fiber core material as the core is also likely to be the mainstream in building applications. Therefore, in this paper, we report the comparison of the measurement results of the long-term performance in the building environment of VIPs using glass fiber and the calculation result. We also describe the calculation method of long-term performance prediction

Effect of Air Pressure on Moisture Transfer inside Porous Building Materials Three-dimensional Behavior of Moisture and Air

The effect of air pressure on moisture transfer inside porous building materials cannot be ignored in cases in which air cannot escape through the surfaces of the materials; in such cases, the air is compressed by the movement of the moisture. Therefore, in a situation in which most surfaces of a specimen are sealed or treated with surface-protecting materials (a situation that is often encountered in typical water-absorption tests), the experimental results may differ from those without sealed or treated surfaces. In the present study, the influence of air pressure on moisture transfer was investigated quantitatively. First, the following water-absorption test was conducted. Water infiltrated into a brick through its top surface, whereas the side surfaces were sealed to prevent the transfer of moisture and air. The bottom surface was exposed to the ambient air. The water content was measured twodimensionally during the experiment using gamma-ray attenuation. Next, to investigate how air pressure affects water infiltration, another experiment was conducted after sealing the bottom surface. The air inside the brick was expected to be compressed by the infiltrating water when the bottom surface was sealed. A water-absorption test was then performed after a small hole was made in a side surface of the bottom-sealed brick to reduce the interior air pressure. Finally, we analyzed the experiments numerically using a three-dimensional calculation model for simultaneous air and moisture transfer, assessing the validity of the model by comparing the calculated and measured water contents. The experimental and numerical results show that water infiltration is slowed by higher air pressure inside the specimen when it is difficult for air to escape. It is also shown that the hole in the side surface helped limit the rise in air pressure to some extent

Evaluating the Energy Consumption and Heat Loss in the Hot Water Supply and Heating Systems of a Nursing Home

The demand for nursing homes has increased recently due to an increase in the aging population in Japan. Nursing homes are generally equipped with hot water supply and heating systems for bathing, preparing meals, and heating rooms. This equipment utilizes a considerable amount of energy. Few studies have measured heat loss from the hot water supply and heating systems in such facilities. This study evaluated the hot water supply and heating systems of a nursing home located in a cold climate area in Japan. The temperature and flow rate of the hot water were continuously measured, and the energy consumption and heat loss for each subsystem were calculated. These results clarified that the energy consumption in the hot water supply subsystem was slightly larger than that in heating subsystem. Inefficiencies of the system were also continuously evaluated throughout the study. Heat losses in piping attributed to 38% of the total energy consumed by the hot water supply subsystem. Subsequently, a thermal analysis of the hot water subsystem was performed. The calculated return temperature agreed with the measured return temperatures when the resistance of thermal insulation was decreased by an average of 45%; this result was possibly due to the deterioration of thermal insulation materials or the presence of thermal bridges

Predicting Hygrothermal Behavior of an Underground Stone Chamber with 3-D Modeling to Restrain Water-Related Damage to Mural Paintings

Cultural properties are variously influenced by their surrounding environmental conditions. One of the reasons for the deterioration of mural paintings in the Takamatsuzuka Tumulus was the humid microclimate on their surface. In order to control the deterioration of mural paintings caused by such problems, it is important to investigate the environmental factors from various aspects, such as the temperature, humidity, water content of cultural properties, wetting and drying cycles and so on. As for the research concerning hygrothermal behavior on mural paintings, these variables may not be thoroughly predicted by 1-D or 2-D for determination of the location and degree of the deterioration of mural paintings. This paper shows how a 3-D hygrothermal model developed with a view to analyzing the preservation measures that allow quantifying of the degree of drying and condensing processes occurred on the surfaces of the underground chamber. The findings show that for the purpose of preserving mural paintings within the underground chamber, the temperature difference between the surrounding mound and the protected object should be kept as constant as can be practically achieved. This method is applicable for estimating the effects of preservation measures for the conservation of other mural paintings