We know that a plant is useful to have a relaxation in our life in case of suffering a mental stress, but it is not enough to clarify an usefulness of a plant under a condition of existing in a room. In this study we tried to know the correlation between plants and our cognition under the mental stressed condition by the use of questionnaire and the measurement of electroencephalogram (EEG) of the subjects. The psychological aspects of the subject were investigated by Principle Components analysis of the evaluation score by using adjectives following Semantic Differential method. The data of the electrocardiogram were analyzed by Fast Fourier transformation to know the physiological impacts to the subject. The following results were obtained from the study on the influence by virtue of the presence and absence of the plant and the arrangement of the plant location with regard to the psychological and the physiological consideration. (1) The subject under the condition of sitting on the chair without working: a) The mental evaluation score of "annoyance" and the principal component score of "bright" and "arousal" were increased by existing the plant. b) The mental evaluation score of "annoyance" in the experimental group of the location at the height of eyes was greater than that of the location on the floor. c) In case of the plant location in the central position at the height of eyes, the percentage of α wave component in the electroen-cephalogram showed the greatest value in all cases. (2) The subject under the condition of being mental stress: a) The mental evaluation score of "calm" and "open" were increased by existing the plant. b) The maximum percentage of α-wave component was obtained in case of the location over the full width of the wall at the height of eyes. (3) It is recognized that the correlation among the mental evaluation score of "calm", the principle component score of "open" and the percentage of α-wave component. (4) It was shown that the influence of the plant to the subject was dependent on the location of the plant at the wall in the room.

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The experiments of synthetic wastewater treatment were carried out by using a bench-scale unit of submerged membrane separation activated sludge process, in order to examine the effect of organic loading of wastewater and sludge retention time "SRT" on accumulation of dissolved organic compounds in the membrane separation tank. We also investigated the relations between the accumulation of dissolved organic compounds and the performance of membrane permeation. As a result, it was found that the organic compound accumulation in the tank caused the membrane fouling. Low organic loading or low SRT by frequent sludge drawing was effective against the accumulation of dissolved organic compounds. Furthermore, under the condition of very low organic loading the sludge concentration in the tank was kept constant without drawing the sludge from the tank.

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Consideration must be given to the rates and paths of airflow when designing an airtight house in order to prevent possible future problems of air quality. In winter, an airtight house that uses heating can be easily ventilated by a passive ventilation system. On the other hand, an alternative system, such cross ventilation, must be used in summer. In this study, characteristics of the rates and paths of airflow due to the stack effect in winter and the buoyant effect in summer were discussed. The rates and paths of the passive ventilation in an airtight test house were measured by using the multiple tracer gas technique. The following conclusions were drawn from the results of this study. 1) A vertical duct and earth tubes are useful for a passive system. The uses of small fans installed between rooms and a vertical duct reduce the amount of used air, and they help the passive system. Each fan supplies the required ventilation rates into each room and also relieves thermal discomfort at the floor level. 2) Sufficient airflow rates due to the buoyant effect in summer can be expected when a roof window over the attic space is opened, and the buoyant ventilation will improve the thermal environment in summer.

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Energy saving characteristics of combined heat and power system using waste heat from refuse incinerator is investigated by numerical simulation. If heat supply to neighboring district heating and cooling plant is possible, the amount of energy saving of the CHP system is larger than power generation only. Especially, when the amount of heat demand is sufficiently enough as compared with the waste heat, its predominance is remarkable. Five types of steam turbine are simulated, that is, condensing turbine, single or multi stage condensing extraction turbine, backpressure turbine, backpressure extraction turbine with clutch. When the heat demand is large, turbines which can change the amount and temperature of extracted heat according to the amount of heat demand are superior to the backpressure turbine. The result of economical analysis shows that the economical feasibility strongly depends on the amount of heat demand and the distance between refuse incinerator and district heating and cooling plant since installation cost of heat distribution pipeline is dominant. It means that it is very important to locate refuse incineration plant near the business district or the densely inhabited area.

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The global environmental issues are getting serious requiring general public for their understandings and cooperatives to the issues. We conducted the first social survey for urban inhabitants to these issues at seven areas in the four cities in 1997 and reported the structures of inhabitants' consciousness to the global environmental issues in the former paper (Part. 1). At the second step the authors made two types of questionnaires that were designed to stimulate subjects and accelerate the reform of their mind. The respondents to the first survey were divided into two groups and the second survey was conducted to the one group with the incentive questionnaires and to the other with the normal questionnaires in 1998. In this paper (Part. 2) we explained the outline of the second survey at six areas in three cities and discussed the characteristics of the two incentive questionnaires' effects. The results were summarized as follows. 1. We compared the proportions of the answers between before and after the incentive. In the group motivated by bias information there were no significant changes at all questions. The incentive by Delphi method had effects at some questions asking the anxieties, but no effects at the questions asking the actions. 2. Using the correlation analysis and the cross table analysis, the effects of the incentive questionnaires were analyzed. In the group motivated with Delphi method, some correlation coefficients between the items became lower after the incentive than before. That was between the two questions asking the anxieties and other questions. The incentive by Delphi method influenced independently the two questions. 3. On the other hand, some correlation coefficients got higher in the group motivated by the bias information. That was between the questions asking subject' concerns or anxieties and subject' actions. So the bias information did not have large effects but had the effects to connect subject's concerns or anxieties to subject's actions. 4. The subjects were classified into four groups by their images to "energy conservation and saving materials." The four groups were compared in respect of the effects of the incentive. The incentive by Delphi method had no differences among the four groups. The subjects of the groups with the image of 'saving money' significantly had higher concerns and anxieties to the global environmental issues than the others.

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Recently, apartment houses have increasingly been constructed in urban area, because of the increasing advanced aged and the needs to live near the working site. Urban apartment houses have the different feature for the hot water supply loads comparing to the ordinary houses and therefor, up-to-date hot water supply loads data are necessary for the planning of saving energy system, for example, the co-generation system. In this paper, we report measurement analysis of hot water supply loads in urban apartment houses for about 200 flats. And we describe the trend of the daily hot water supply loads pattern of weekday and weekend, and maximum hot water supply loads in various time intervals. Furthermore, we arranged the basic planning and designing data with the hot water simultaneous uses in apartment houses. These data are based on our measurement results, and the analyses of actual measurement data reported by various domestic documents.

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Recently the recycling system of kichen refuses by disposers has come into wide use. In order to fulfill its functions as a system, the authors found it necessary to test the efficiencies of the disposers themselves from the various points of view. In this paper, the authors made experiments on their grinding and discharge characteristics, by using 8 types of disposers in the market. Then the authors also presented the performance evaluation of their characteristics.

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Experiments on batch aerobic digestion in continuous aeration were carried out. The activated sludges acclimated to glucose at various sludge ages and the sludge of a municipal wastewater treatment plant were used. The VSS/SS of the acclimated sludges kept a constant value during digestion, while that of the sludge of the municipal wastewater treatment plant decreased during the progress of digestion. As sludge age decreased, VSS decreased quickly with the progress of digestion and the final ratio of VSS decomposition increased. The decomposition rate of sludge was proportional to the biodegradable VSS, and its proportional constant (rate constant of decomposition) increased as sludge age decreased. Furthermore, the oxygen uptake rate of sludge was related to the decomposition rate of VSS for both acclimated sludge and municipal wastewater treatment plant sludge, based on the reaction model of aerobic digestion.

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This paper constitutes Part 3 in the series of studies on hybrid utilization of renewable energy for a low energy house in which a ground source heat pump system is applied for heating and cooling as a main strategy. First of all, evaluation program of the low energy house was developed, and the program was verified to give good predictions on the performance of natural energy utilization systems by comparing with experimental results. Secondly, numerical analyses on capacity and efficiency of the ground source heat pump system (GSHP) were carried out and it was found that the amount of annual primary energy was reduced from 20% to 50% compared to that of typical heating. As a result of evaluation on annual energy balance of the low energy house, it was clarified that the self-sufficiency of energy was possible to realize in main domestic regions by applying GSHP system.

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A novel tower-style thermal storage tank has been devised, which features simultaneous storing of warm water and ice. The principle of the storage tank is to store warm water in the upper section and ice in the lower section of a single unit. The storage tank has already been applied at a middle-scale office building. To prevent warm and cold water from intermixing in the tank, a trap shaped density-stabilizing unit, called the "Duo Stable", is installed in the middle of the tank. This research focused on collecting operating data from the storage tank and the exhaust heat recovery heat pump the period of one year. We then analyzed the peak shaving factor and thermal storage efficiency. The results clarified the high performance of this Novel tower-style tank.

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To develope the fault detection & diagnosis system of air-conditioning systems, is important to gather field data and analyze actual faults. We gathered measurement and set point data from almost all controllers of the air-conditioning systems of one large scale building. We prepared the graphs of collected data and checked them on the basis of control informations with the site engineer in charge. And, we classified the knowleges derived from these procedures into basic symptoms, condition of disease, countermeasure list and check flow diagram. These results will be very useful to establish an automatic inspection method by developing effective fault detecting and diagnostic algorism. We will re-evaluate these knowleges for the similar air-conditioning system of other buildings

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