In this paper, the authors report on the thermal storage amount of a PCM window shade having different melting points, an examination of its use as an external sun shade. When the window shade filled with gelled PCM was installed in a window, the authors confirmed that the maximum surface temperature of PCM window shade reduced by up to 4-7K. In addition, the solar heat transmission could be reduced by about 12% when the blind was installed. In addition, the effect of PCM window shade could be applied to the granular PCM as new material in order to solve the problem of workability in the same manner. The workability of granular PCM could be easily adjusted with filled mixing even for different melting points. When mixing PCM of different melting points, the thermal storage amount showed the intermediate characteristics of both. The solar transmittance of the window shade was improved to 0.9 by filling with the granular PCM. Finally, the solar radiation shielding performance of the PCM blind filled by mixing granular PCM of 50℃and 32℃ melting point was almost as same as that of the gelled PCM of 25℃.

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The purpose of this study is to develop a supply air dew point temperature control of a desiccant air-conditioning system for low-humidity environments. To develop the control, we need to know the basic characteristics of the desiccant air conditioning system, which is a controlled system. In this paper, we construct a mathematical model and analyze systematically the basic characteristics of the controlled system. Specifically, we investigate the static and dynamic characteristics of the controlled system with respect to manipulated variables such as desiccant-wheel rotary speed and regeneration outside air flow rate. For static characteristics, we investigate the relation between controlled and manipulated variables and examine the influence of manipulated variables on controlled variables. For dynamic characteristics, we investigate the step response of controlled variables and examine the responsivity or overshoot of controlled variables.

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Indoor air quality affects occupants' health and comfort. Poor indoor environmental conditions and gas-phase/aerosol-phase contaminants in indoors are also identified as one of the causes of illnesses such as asthma and allergy, and known to result in significant loss of productivity because of its adverse effect on health. In recent years, photocatalytic oxidation (PCO) process have attracted attention because they are effective in purification of indoor air polluted with volatile organic compounds (VOCs), especially at low concentration levels. Thus far, TiO_2, one of the photocatalyst bound building materials, has been extensively studied for the oxidation of indoor air pollutants. The purpose of this research is to establish of Numerical Prediction of Concentration Reduction Performance of VOCs indoors. In this study, kinetic studies were carried out on photocatalytic oxidation (PCO) of toluene as VOCs in the gas phase over TiO_2-bound building materials in a 20 L test chamber and computational fluid dynamics (CFD) simulations were performed using the same boundary conditions as the experiments to identify model parameters of the PCO process. A performance test for evaluating the reduction of toluene concentration was carried out according to the ISO 16000-24 procedure (ISO, 2009) using a rectangular test chamber and a TiO_2-coated building material through a thermal spraying technique. TiO_2 powder was retained on the the surface of a material in the absence of any specific binder. Toluene concentration-controlled air was supplied into the chamber via an inlet located at the bottom of the chamber using a precise gas generator. The concentrations of toluene and products in the gas phase were determined using gas chromatography (GC/FID) by collecting samples from the outlet located on the ceiling of the test chamber. In this paper, we show the experimental results of photo-catalytic degradation on toluene concentration and the identification result of the kinetic model parameters of the Langmuir-Hinshelwood model on the PCO process in combination with CFD simulations. The Langmuir-Hinshelwood model was applied to the first control volume from the building material surface as a source term (sink term). The error of the reaction rate constant obtained in the experiment was corrected and adjusted through CFD analysis. The reaction rate constant k and Langmuir adsorption constant K were 1.78×10^<-10> kg/m^2/s, 1.16×10^6 m^3/kg, respectively.

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The aim of this study is to develop a new technology to remove accreted snow safely and less expensively. The cyclic heating method, a combination process of heating and cooling, involves the formation of a thin freezing layer on the contact surface of the accreted snow, and to ease slipping down at the final heating process. Compare with the melting method, there are some advantages such as relatively low energy consumption and no icicle formation by refreezing of melt water. A simulated snow of 40mm square area was placed on an aluminum plate with given depth of 15, 20 and 25mm. The cyclic heating process involves heating for 2, 3 or 4 s, active cooling for 30 s and natural cooling for 90 second. The active heating and cooling of the plate is performed using a Peltier device set on the opposite side of the plate. The first experiment to judge accreted snow slipping-down showed successful conditions of the number of cycles, heating time and depth of accreted snow. The second experiment of freezing layer observation showed accreted depths of 20mm or more and a freezing area ratio of 90% or more resulted in slipping down of accreted snow.

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Recently it has become important to study net-zero energy buildings and load leveling of buildings to limit power demand. This study intends to clarify efficient equipment operation method and economy for load leveling. Approaches for load leveling are as the follows: a) use of renewable energy, b) reduction of electric load, and c) use of thermal storage tanks and storage batteries. The reproduction of the simulation tool is confirmed through a comparison between experiments and simulations. Results of case studies using the simulation demonstrate that the reduction of electric load is the most effective method for load leveling. In addition, it is possible to achieve both indoor comfort and load leveling through the combined use of load reduction, renewable energy and storage batteries.

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In recent years, the adoption of energy-saving measures such as turning off the lights automatically while workers are absent and introducing office automation equipment with sleep mode have been widely promoted in workplaces. These measures tend to cause internal thermal load or absence of workers differences in workplaces depending on the presence. Therefore, an air-conditioning system design capable of maintaining an appropriate energy-saving indoor thermal environment is required. In this study, a workplace was modeled where several combinations of patterns in accordance with the absence or presence of workers were used to assume the variations in internal thermal load generation to quantitatively study different thermal load environments. Furthermore, a case study for air conditioning improvements regarding internal thermal load difference is presented for a general-type single-duct VAV system, and the effect of the improvements considering both energy saving and the appropriate indoor thermal environment. Practical design methods were also evaluated through the simulations. From the result, we found that it was important to perform dehumidification in cases where the internal thermal load was small, to stop air supply where the workers were absent and to design each air conditioning equipment satisfying the appropriate capacity according to the space scaling.

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Ventilation efficiency such as the hood capture efficiency is influenced by disturbances due to moving bodies and airflow caused by HVAC systems. Airflow from the supply opening of an HVAC system can be considered on the basis of experiments and CFD simulation. However, air disturbance due to a moving body is generally ignored in the HVAC design. In this study, thermal plume over a cooking range was examined through CFD simulation with a moving body. The influences of disturbance on thermal plume for two types of layout, i.e. the wall-mount type and the island type were compared. In case of the wall-mount layout, thermal plume was shaken by the moving panel more strongly than in the island layout.

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Most of the energy in the university campus is consumed by air-conditioning units and therefore it must be managed for saving energy. In recent years, adoption of the multi-split air-conditioning system has increased, but the actual situation of its operation has not been clarified and hence, rational examination cannot be conducted reading its design and use. After performing operative fact-finding of the air-conditioning system at Tokyo University, the actual situation that capacity was excessive and driving of the low load factor caused an efficiency drop became clear. Therefore, an actual survey of buildings subjected to modification was conducted by defining their own capacity selection criterion in order to correct the excessive capacity. The examined operations were reported in order to achieve more energy saving and realize the concept of equipment selection.

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The visualization of energy consumption in small and medium sized buildings have been spreading rapidly in recent years owing to generalization and reduction in the price of energy measurement equipment. However, utilization of the stored data for daily maintenance has not been sufficient so far because of lack of users skilled in data analysis techniques. On the other hand, the demand from building administrators who seek useful information on utilization of stored data has been increasing for further energy conservation and preventive maintenance of HVAC component. The purpose of this study is to develop a fault detection system that can detect faults in air-conditioning equipment and provide useful information to building administrators who seek to rationalize daily operation management to achieve their goals. Utilization of this system results in not only energy waste prevention but also appropriate renewal time judgement of the HVAC system. In this paper, a fault detection system for heat source supply system is outlined and its fault detection algorithms are presented.

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