The purpose of this study is to identify acceptable luminance range of translucent thermal insulation walls, in order to decide optical transmittance of the walls, especially. Two series of subjective experiments with actual translucent thermal insulation walls were carried out in a full-scale building. The first experiment showed the relationship between the luminance of the walls and discomfort glare evaluation, GSV, while the second experiment showed the relationship between the luminance of the walls and brightness of the walls. It was found that the suitable brightness was give by the luminance ranging from 300 to 3000 [cd/m²], that was influenced by the plan of the room and the size of the walls and the windows.

View full abstract

Thermal comfort in a heated room is much affected by the characteristics of envelop, especially its thermal insulation properties and the heating system. Coupled convection-radiation simulation is conducted to estimate heat release from a floor heating system or a wall-mounted air-conditioning unit under the same equivalent temperature with simulated human body under five building insulation levels including three levels of Japanese energy conservation standards for residential building. A human body model is placed on the floor in a seated posture and controlled by comfort regulation of thermal manikin. In computations, sensible heat release from the human body is matched for different heating systems by properly controlling temperature of the heating panels under the floor or hot air from the air-conditioner. When heat loss from the bottom of the heating panels is neglected, heat release from the floor heating system is smaller than that from the air-conditioning unit.

View full abstract

This research aims at developing the moisture exhaust exterior wall which can discharge indoor humidity to the outdoor air by using a part of exterior wall as the monolayer wall of the humidity control building materials which have permeability. Indoor humidity can be naturally discharged using the water-vapor-pressure difference between the indoor air and the outdoor air in winter. In this paper, the reduction effect of indoor relative humidity is shown based on the experimental result which used the climate chamber. The building-material load factor and the moisture exhaust slope were specified as indexes showing the performance of the moisture exhaust exterior wall. Since the relation between the building-material load factor and the time required for specific reductions in indoor relative humidity was analyzed, and selection of a building-material load factor corresponding to the house conditions was possible.

View full abstract

In this study, the wall greening by vine with a simple net was constructed on the west side wall. For the purpose of quantitative evaluation for mitigation effect of thermal load by using wall greening, the model to estimate the solar radiation through the glass window was discussed. Estimated cumulative thermal load of solar radiation was corresponding to observed value. The mean error of transmissivity estimation every two hours from 9 AM to 5 PM was 0.90%, 0.89%, 2.02% and 3.17%, respectively. Our model tended to overestimate the sun-shading effect by wall greening from 3PM to 5PM in sparsity leaf condition of which the LAI was under 1.0. The relationship between the LAI of greening wall and the mean of solar radiation transmissivity through the window has a negative correlation. Each same time period, observed mean of solar radiation transmissivity through the window was reduced 4.40%, 4.15%, 6.53% and 10.13%, respectively with increase of LAI per unit.

View full abstract

In recent years, cities have had to face the growing possibility of accidental pollution, such as leakage of city gas or radioactive particles. Also, we cannot neglect the possibility of CBR (chemical, biological or radioactive) terrorist attacks. When we suppose such condition, the arrival time of concentration of tracer gas which was emitted in the typical point in an urban area might be the important information for the rescue teams and emergency responders. The wind tunnel experiment was conducted by using the architectural model of Iidabashi district which scale was 1/500. The concentration was discharged unsteadily and arrival time of concentration was measured for 32 times in each measurement cases. By averaging the arrival time of every acquisition, the average tendency was considered. Also, this paper shows the characteristics of the concentration fluctuation in the constant condition (after the transient rising of concentration). The stochastic values, the higher order moments were calculated. The profile of probability density function (PDF) is shown. In general, profile of PDF is typified by three types in the dispersion phenomena, which is exponential distribution, normal distribution, lognormal distribution. Each case was examined to fit to these distributions. The higher order moments is analyzed in order to understand the characteristics of the PDF.

View full abstract

In medical institutions including hospitals, it is an essential examination procedure to collect data of outputs and flow rates of patients' urine for ensuring correct health management and diagnosis. This study proposes a method for testing the performance of a toilet with an uroflowmeter, which is developed for this very purpose, when the toilet is installed to a stack system, and examines how effective the method may be according to the results, with the intention of clarifying the variation of pipe pressure allowable when the toilet is installed to a drainage ventilation system.
To be more specific, this study discusses the following points: 1. the examination of how effective the abovementioned method may be for testing the performance of the toilet by applying the previously proposed method for testing the combined drainage performance of the house drain; 2. the examination of the influence of pipe pressure variations, which are caused by applying drainage loads using the aforementioned test method, on the accuracy of performance indicators, such as urine outputs, the maximum urine flow rate, urine flow curves; and finally, on the basis of the results acquired, the range of variation of pipe pressure allowable in the design of drainage and ventilation pipework is clarified.

View full abstract

This report presents calculations of the CO₂ emissions during the transportation and processing of each class of recyclable materials recovered from waste of the operations in an office building. Emissions were shown to correlate with the rate of resource recovery from municipal solid wastes, and areas of waste collection points in buildings needed in order to recover resources were estimated. The findings are as follows.
1) Great variation was seen in the actual values of the rate of resource recovery due to variations in how the wastes were generated and in the methods of separation and recovery used in the buildings, but the mean of the rate of resource recovery in the surveyed buildings was approximately 60%.
2) Comparing with the volume of generated wastes for each class of recovered materials between before and after promulgation of the Basic Act on Establishing a sound Material Cycle Society indicated a tendency for the enforcement of these laws to suppress the volumes of each class.
3) When the actual resource recovery of wastes from the monitored buildings reached about 60%, the CO₂ emissions due to transportation and processing were estimated to be equivalent to the reduction in CO₂ emissions during the resource recovery.
4) Targets were set for waste collection point area ratios of 0.4% and 0.35% for property areas up to 30,000 m² and 50,000 m², respectively to make it convenient to recover resources. These were roughly equal to the ratios found in the buildings surveyed. About 0.8% was estimated to be needed in property areas of 10,000 m² or less. These findings suggest that the current standard was set by the municipalities regulation is too small.

View full abstract

The Underfloor Plenum Building Structure Thermal Storage (UP-BSTS) HVAC system is a system which mainly utilizes a concrete floor slab and the modular cement floor panels built above its slab, which acts as a thermal storage device. Cold air is supplied to the underfloor space composed of the slab and panels as a plenum chamber to store heat, and then returns from the outlets in the space to an AHU at night in the summer. Cold air also flows through the openings on the floor panels from the chamber into a room and circulates through the room and ceiling chamber to the AHU during the normal daytime cooling operation mode.
This paper reports the results of experiments to ascertain how key factors for the design and operation of the UP-BSTS HVAC system affect quantitatively the heat charge/discharge performances of its system. The results can be obtained as follows:
1) The average heat removed from the slab with panels is 382kJ/m² (floor area) for 5 heat charging operation hours and 446 kJ/m² for 7.5 hours respectively.
2) It is more important to increase the heat charged during the nighttime by varying the supply air temperature and supply air volume rather than by changing the heat charging operation hours.
3) The decrease in the heat removed during the nighttime leads to a decrease in the heat discharged during the daytime, which could cause the inexpedient heat charge during hours of HVAC operation.

View full abstract

The thermal resistance of adiabatic material sometimes degenerates after a long time use. For existing residential house, it is important to measure the thermal transmittance (U-value) of the walls. The infrared camera method was often used as nondestructive in situ measuring method enabling simple field test. The purpose of this paper is to estimate the feasibility of this method using numerical simulation and experiment. At first, in situ measuring of wall resistance value in a typical residential house was carried out to validate the results of numerical simulation. After the validation, the difference of thermal transmittance among the positions in the same wall was simulated. Moreover, this paper examined how much the different heat-convection stove positions affect the result of thermal transmittance of wall. The simulation results confirmed that measurement accuracy can be sufficiently guaranteed. However, there is the risk of error in the thermal transmittance measurement, if an indoor heat-convection stove is located too near the measurement wall in the room.

View full abstract

This paper presents the study of DHC (district heating and cooling) business in 3 northeast Asian cities-Tokyo, Beijing and Seoul, in which, projects like initial background, annual fluctuation, current status and heat rate system were investigated. The difference and the feature of DHC use in the city in a country different through the comparison of three cities are analyzed, As a result, this paper may propose a material for DHC business progressing and a new way about the environmental policy in the future. During the period of 2006, DHC annual sales showed big differences in 3 cities. It can be seen that sales for houses and Commercial buildings were also different. The differences of the heat rate unit price by the heat service area of the DHC were large in Tokyo, while small in Beijing and Seoul. Additionally, by use of the building thermal model and comparing individual heat source system, the difference between DHC heat rates in 3 cities is confirmed.

View full abstract

In this study, the daily changes in the resident's living space and their environmental adjustment behavior in summer was examined, aiming at evaluating the thermal environment in the Edo townsmen's residential area using the numerical simulation. The information of resident's living activities was extracted from the historical materials in the Edo and Meiji period, concerning the types of the residents and the daily time sections. The resident's living space and environmental adjustment behavior was identified from those extracted resident's living activities, and the characteristics of the daily changes of living space and environmental adjustment behavior were grasped.

View full abstract

This study is aiming at evaluating resultant distributions of thermal and airflow environment in a room ventilated with various air supply openings, and comparing input energy required for heating with floor heating systems or with convective heating systems. Experiments were conducted for different PMV levels. The results are summarized as follows: 1) Conditions of the warm jet issuing from convective heating system significantly affect the vertical and horizontal temperature differences, airflow structures, DR and PMV values. 2) Thermal and airflow environment is maintained uniform, and DR values in most places are kept under 15% during heating with floor heating system. 3) Attachment points and diffusion paths of the ventilated air are markedly different depending on the air supply openings. 4) Input energy required for heating with floor heating system is roughly 20% smaller than that of convective heating system if evaluated with secondary energy directly concerned with room heating.

View full abstract