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Article type: Cover
2001 Volume 26 Issue 83 Pages
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Published: October 25, 2001
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Article type: Cover
2001 Volume 26 Issue 83 Pages
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Article type: Index
2001 Volume 26 Issue 83 Pages
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Akira KONDO, Akikazu KAGA, Eriko GODA, Katsuhito YAMAGUCHI, Kenji MIZU ...
Article type: Article
2001 Volume 26 Issue 83 Pages
1-9
Published: October 25, 2001
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We proposed the numerical model that can consider thermal environmental effect of green, water surface, and buildings, in order to predict thermal environmental change by development of a few km^2 scales. The previous report demonstrated that this numerical model could reproduce well the flow fields in the development area at Minoo, Osaka. This report demonstrated that this numerical model could reproduce well the temperature fields, too. Subsequently, we estimated the influence on thermal environmental change by dam development, by the difference of green coverage and by the difference of road albedo value. The results obtained by numerical simulations were qualitatively appropriate. It is necessary to discuss about the quantitative accuracy of the results.
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Masashi MOMOTA, Tadahiko IBAMOTO, Takumo MIYANAGA, Hiroshi YAMADA, Hir ...
Article type: Article
2001 Volume 26 Issue 83 Pages
11-20
Published: October 25, 2001
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Today, we often hear the words, "stop the waste of energy" or "protect the environment". These keywords take all of specialists for changing their stance to study. To choose an easy method, not thinking about the impact on environment, would be an old style. According to this movement, District Cooling (DC) needs to change in the future. In this report, we suggested the transportation system using ice & water with blocked ice. The main character of this system is to maintain ice constantly in the pipeline. The important point is that there are no differences of temperature between upstream to down stream in the piping. We think that the system can compose simple single loop of piping not by double loop of piping as it is used generally in DC. But there are few problems to control the system. Therefore, first of all, we made an experiment about characteristic of pressure loss and measurement method of IPF in the pipeline. [Characteristic of pressure loss] We confirmed that it is possible to put the transportation system using ice & water with blocked ice in practical use. Resulting from this experiment, we are capable of predicting characteristic of pressure loss when changing diameter of pipeline, IPF and flow velocity. [Measurement method of IPF in the pipeline] We suggested to use ultra sonic density meter for measuring IPF in the pipeline, and succeeded the research of effectual real-time measurement of IPF using ultra sonic density meter. There are problems that manufacturing the block ice, method of casting ice into pipeline, and so on. To solve these problems will be the key to succeed in the transportation system using ice & water.
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Yasuhiro HAMADA, Makoto NAKAMURA, Kiyoshi OCHIFUJI, Ryoko NARITA, Kaor ...
Article type: Article
2001 Volume 26 Issue 83 Pages
21-30
Published: October 25, 2001
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This paper describes the effectiveness of a hybrid solar collector which generates both electric power and heat. Experiments and analyses on characteristics of power and heat generation through the hybrid solar collector were carried out. Firstly, experiments under the condition of constant supply temperature of brine were made and it was found that collector efficiency on electric power was from 10 to 13%, and that its efficiency on heat at 20℃-brine temperature and 40℃ was from 40 to 50% and approximately 20%, respectively. Secondly, the efficiency of the hybrid solar collector was compared with a photovoltaic and a solar collector and it was clarified that the hybrid collector had an advantage from the viewpoint of the exergy efficiency, though there are some lowering on heat collection efficiency. As a result of evaluation on annual energy balance of hybrid solar collectors installed for a low energy house in Hokkaido University, it was proven that the feasibility of the hybrid solar collectors was high.
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Yoshiaki ISHIZU
Article type: Article
2001 Volume 26 Issue 83 Pages
31-34
Published: October 25, 2001
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Introducing clearly defined two parameters, m and p, a revised m-p model was proposed. The revised m-p model provides exact value of the averaged concentration of indoor air contaminants with a simple calculation. The validity of the model was also confirmed by analytical calculation. Here, m is a mixing factor showing ventilation efficiency and p is a position factor showing the effect of contaminant generation site.
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Akira TAKAKUSAGI
Article type: Article
2001 Volume 26 Issue 83 Pages
35-44
Published: October 25, 2001
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The purpose of this paper is to present the basic method and some materials for the constant air volume air conditioning system's PID parameters tuning. At first, the theoretical expression of the indicial response of room air temperature for the unit step function of heat input at air conditioning unit is derived. The circulation of the air is considered in this dynamic model that makes the part of the rise of the response precise. Using this indicial response expression, the optimal value of PID parameters in follow up control can be computed. Then, several factors that may relates to the dynamic characteristic of room air temperature that is expressed by the indicial response, are supposed and three level variables are given to each factor. Using the "design of experiments" method, the influence of the difference of conditions concerning to the building specifications and air conditioning system characteristics to the optimal values of PID parameters is analyzed.
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Hiroshi Okano, Tsutomu Hirose
Article type: Article
2001 Volume 26 Issue 83 Pages
45-51
Published: October 25, 2001
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A total heat energy exchanger is an energy-saving device used for air conditioning/ventilation in buildings and so on. It exchanges and recovers both sensitive heat and latent heat at the same time. A total heat energy exchanger in its early stage of development was made of an asbestos paper honeycomb rotor impregnated with lithium chloride as a latent heat exchanging agent. But it had problems such as cancer causing possibility of asbestos, efficiency decrease, damages of devices by salt corroding due to the outflow of lithium chloride in high humidity conditions and so on. In order to solve these problems, a method of giving latent heat exchanging function to an aluminum sheet having sensitive heat exchanging function only was developed by carrying solid adsorbent on the sheet, and an aluminum total heat energy exchanger with excellent efficiency was successfully put in practical use.
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Takashi KURABUCHI, Akihiro ARASHIGUCHI, Masashi IMANO, Motoyasu KAMATA ...
Article type: Article
2001 Volume 26 Issue 83 Pages
53-63
Published: October 25, 2001
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An evaluation technique was developed for fulfilled level of ventilation rate requirement for occupied rooms of apartment houses based on estimated frequency of wind pressure acting on external wall of building by analyzing climate data and wind pressure coefficients, and airflow network calculation. Wind pressure coefficients of super high-rise apartment building were determined by newly performed wind tunnel experiment. Wind pressure coefficient of center core was evaluated by airflow network calculation for a modeled single story part of building. Developed technique was applied to center core type super high-rise apartment houses constantly ventilated with suction type mechanical ventilation system hypothetically located on various principal cities in Japan and in Tokyo area. Resultant ventilation rate for occupied rooms of an apartment house was estimated for various conditions of imposed air tightness and wind pressure using airflow network calculation. Significant difference was found on estimated frequencies of wind pressure acting on external wall of building for various principal cities in Japan, and observed difference on wind pressure frequencies was relatively small among cities in Tokyo area. Frequency distribution of wind pressure was well approximated by Weibull distribution. Air tightness of entrance door was found to exert decisive influence on fulfilled level of ventilation rate requirement of center core type super high-rise apartment, and the effect of overall air tightness was relatively small.
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Mingjie ZHENG, Yoshihiko NISHITANI, Nobuo NAKAHARA
Article type: Article
2001 Volume 26 Issue 83 Pages
65-74
Published: October 25, 2001
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To control the thermal storage operation properly, it is necessary to predict the heat load of the next day in advance. The present paper focuses on a load prediction method based on GMDH through the examination of initial input variable, regular procedure, convergent condition for repeated calculation, and length of learning period. It has verified that the heat load prediction method based on GMDH can predict the heat load in sufficient precision, and that quantities of solar radiation at the few hours ago are effective by comparing the load prediction per hour with load prediction per day. Moreover it has been made clear that strong and weak points of the heat load prediction method based on GMDH through the comparison of load predictions for two buildings, have difference feature of the heat load.
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Takao TSUSHIMA, Yoshihiro SHIMAOKA, Nobuyuki HIRAMATSU
Article type: Article
2001 Volume 26 Issue 83 Pages
75-80
Published: October 25, 2001
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Uniform outlet duct systems are used widely in each industrial field such as the air-conditioning, the factory ventilation and others. In uniform outlet duct systems, the flow distribution at outlets would become more uniform when the area ratio; M_L (the total sectional areas of the branch ducts/the sectional area of the main duct) gets smaller. In the previous works, based on this idea, precise flow analysis including dividing pressure losses at each branch was done to consider relations between the area ratio; M_L and flow distribution. Through the calculations, we clarified the design conditions in which the flow distribution at outlets came uniform, and proposed new design method based on the area ratio; M_L. In this paper, to confirm the calculation results, we built the uniform outlet duct systems for experiments. An experimental device consists of spiral ducts on the market and the inverter controlled multiblade fan. Experiments were carried out at the different value of M_L between 0.33 and 1.75. Good agreements between the experimental results and the calculation results are obtained both in the flow distribution and the required total pressure coefficient. It can be said that the proposed new design method based on M_L has been proved experimentally.
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Hyunjae Chang, Shinsuke Kato, Shuzo Murakami, Tomoyuki Chikamoto, Taey ...
Article type: Article
2001 Volume 26 Issue 83 Pages
81-90
Published: October 25, 2001
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The characteristics of a hybrid air-conditioning system, utilizing natural and mechanical ventilation, is investigated in an office setting. The application of this hybrid air-conditioning system in intermediate seasons of Spring and Autumn, is expected to improve the indoor air quality (IAQ) on the one hand, and lower the energy consumption on the other. For the designing datum of hybrid air-conditioning system, the characteristics of the indoor environment are examined with CFD (Computational Fluid Dynamics) simulation under various conditions of incoming outdoor air and the opening area of the window for natural cross ventilation. Cooling load of the mechanical air-conditioning system to maintain the task zone at the target temperature (26℃) is analyzed based on the results of these simulations. When the outdoor air of lower temperature than the indoor air flows into the room, it drops near the window opening because of the negative buoyancy effect in the room and cools the task zone energy efficiently.
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Zhen-hai Li, Hiroshi Yoshino, Yasuo Utsumi, Hiroshi Kobayashi, Yukio S ...
Article type: Article
2001 Volume 26 Issue 83 Pages
91-98
Published: October 25, 2001
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In case of mechanical exhaust system, it is pointed out that there may be thermal discomfort due to the cold outdoor air coming through the supply opening located at the outside wall during the heating period. In order to find the solution for preventing this problem, a real scale experiment an environmental chamber was carried out. The results are as follows, (1) The standardized vertical temperature difference is affected by the airflow directions from the supply opening. The highest magnitude is observed for horizontal flow with max value of 0.3. The magnitude increases in the flow directions of "vertical upward with an angle", "radial outward parallel to wall", "radial outward with an angle from wall", "horizontal outward from wall", sequentially. (2) The standardized vertical temperature difference was examined in terms of various opening positions. The magnitudes of the difference decreace in the case of above window, upper of the wall, middle of the wall, lower of the wall sequently. (3) The influence of supply air velocity was not significant with the experiment on vertical temperature difference.
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Article type: Bibliography
2001 Volume 26 Issue 83 Pages
99-120
Published: October 25, 2001
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Article type: Appendix
2001 Volume 26 Issue 83 Pages
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Article type: Cover
2001 Volume 26 Issue 83 Pages
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