Journal of Environmental Engineering (Transactions of AIJ)
Online ISSN : 1881-817X
Print ISSN : 1348-0685
ISSN-L : 1348-0685
Volume 82, Issue 731
Displaying 1-9 of 9 articles from this issue
  • - Studies on the environmental evaluation by subjects' own term Part2 -
    Takaya KOJIMA
    2017 Volume 82 Issue 731 Pages 1-9
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     This study examines the methodology of "individual scaling method" in order to value each person's vocabulary and viewpoints. "Individual scales" refers to evaluation items made by subjects' own terms. Thus, these scales are different from person to person. In the previous report Part1, we proposed principal component analysis (PCA) method for evaluation data measured by individual scales. In this PCA method, evaluation object is regarded as observations, and individual scales of all subjects is regarded as variables. And, individual difference in vocabulary and viewpoint is described as difference in distribution of factor loadings vectors in principal component space. However, suitable method for analyzing individual differences that are described as such has not yet been proposed because of so-called "rotational indeterminacy" related problem.
     In this paper, first, when analyzing individual differences based on proposed PCA method, we discuss the problems caused by so-called "rotational indeterminacy".
     Next, as a solution to this problem, the new method of orthogonal rotation is proposed. This rotation method has the following features.
     ·By the criterion in this method, R-squares matrix of [each person × rotated axes] is directed to simple structure.
     ·By this rotation, individual differences in semantic space is maximized.
     R-squares is measured by personal-PCR (principal component regression analysis), i.e. PCA is performed by each subject, and then by using their each PCA scores as explanatory variables, multiple regression analysis is performed by each subject. Thus, the number of personal PCA scores is an important option in the analysis.
     The criteria to be maximized , we propose the following three. These are another important option.
     a) Sum of variances of columns of R-squares matrix
     b) Sum of variances of columns of Normalized R-squares matrix divided by row sum.
     c) Simply, variance of R-squares
     When replacing R-squares matrix to factor loadings squares matrix, each of the criteria is equivalent to the following well-known criteria.
      a) Row varimax criterion, b) Normal varimax criterion, c) Quartimax criterion
     As a case study, the proposed rotation method was applied on evaluation data of townscape in Kanda area. The results obtained and discussion are as follows .
     1) In this case of data, the results by criterion c) seems to be most useful.
     2) It's recommended to use personal PCA scores of slightly many numbers. In this case, six score is necessary.
     3) Rotated axes are interpreted as follows;
      R1: History and taste, R2: Disorderly-Orderly, R3: Harmony and familiar, R4: Enjoying
     4) Among these axes, R3 and R4 are large individual differences of R-squares. About these individual differences, the following tendencies were found.
      (1) Correlation between R-squares of R3 and R-squares of R4 is negative. Thus, terms to express R3 and terms to express R4, there seem to be not so many people with the both of vocabulary.
      (2) Subjects majoring in architecture have larger R-squares of R3 than other majors, and have smaller R-squares of R4 than other majors.
     Furthermore, from the viewpoint of validity of R-square as indicator of explanatory power, diagnostics of the number of personal PCA scores was discussed.
     Finally, it was noted that there are cases not to require rotation proposed in this paper. And some cases of analysis on such data were presented.
    Download PDF (1159K)
  • No. 2 Examination about the effects of opening of the magnetic shield plate around the electric power line
    Naoya KUBO, Kazunori NISHIMURA, Nobuyoshi KIYOTA
    2017 Volume 82 Issue 731 Pages 11-17
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     Extremely low frequency (ELF) magnetic fields from electric power lines and electric appliances cause errors in the even correct operation of medical and laboratory equipments. High-permeability material plates surrounding all four sides of cables can achieve the best shielding performance. However, the shielding structure reduces the cooling capability and degrades the current carrying capacity of the cable. In a previous report, the authors examined the performance of a magnetic shield using perforated high-permeability alloy plates. In this paper, the authors carried out "the inspection of the heat radiation effect with the opening" and “the relative inspection of the heat radiation effect and the magnetic shielding effect".
     This experimental model was consisted of three electric cables connected to a three-phase AC power supply, and a magnetic shield surrounding the cables. To evaluate the heat radiation effect, the authors measured the temperature of the cable surface, in three-phase AC current 400 A. Each cable was horizontally placed 50 mm away from each other. The magnetic shield was made from 0.5 mm thick, perforated Permalloy PB plates and was formed a square tube with 150 mm x 150 mm x 1000 mm in size. Six types of Permalloy PB plates were tested. The opening ratio was 0% (no ventilating hole), 10%, 20%, 30%, 40% and 50%, respectively. The holes were 5 mm in diameter and arranged in straight centers pattern.
     Next, numerical thermo-fluid 3-D analysis was performed using FVM software, STREAM (Software Cradle Co., Ltd. Japan). The rise in temperature of the cable surface was calculated by models same as the experiment, and the authors defined the calculating formula to evaluate a heat radiation effect with the opening.
     In addition, by the experiment circuit and opening conditions same as the above, the authors measured the magnetic flux density. In this paper, the authors compare the performance of magnetic shielding using the shielding factor, which is the ratio of the measured magnetic flux density to that in non-shielding condition. To evaluate the magnetic shielding effect at the time of the opening, the authors defined the calculating formula of the hold ratio on the basis of a magnetic shielding effect when there was no ventilating hole.
     Main results are follows.
     A: From the inspection of the heat radiation effect by the experiments and the numerical analyses, it was shown that the rise in temperature of the cable surface decreased when the opening area of the shield plate was increasing.
     B: The authors defined the expression of the heat radiation effect, and inspected the difference by the opening rate. In the experiments and analyses, similar characteristics were provided.
     C: In the inspection of the magnetic shielding effect by the experiments, it was shown that the magnetic shielding effect decreased when the opening area of the shield plate was increasing.
     D: In "the heat radiation effect by the opening ratio" and "the hold ratio of the magnetic shielding effect by the opening ratio ", the authors showed the relations of both clearly.
    Download PDF (645K)
  • Kenichi HASEGAWA, Hiroshi YOSHINO, U YANAGI, Kenichi AZUMA, Haruki OSA ...
    2017 Volume 82 Issue 731 Pages 19-29
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     In Japan the Great East Japan Earthquake had occurred on March 11 in 2011. There are serial damages in seaside cities of the Pacific Ocean in Tohoku district. Many people in these areas had lost their houses and more fifty thousand temporary houses were built in three prefectures of the Tohoku district. Most temporary housing units are terrace houses, and distance between buildings is narrow, and the performance of the thermal insulation is not enough to keep an adequate indoor thermal environment and energy conservation. Therefore, we are anxious about the possibility several problems may occur, such as indoor thermal environment and indoor air quality as well as sound environment problems.
     This research aims to propose the optimal environmental design method of temporary housing and show how to improve the environmental policy, after clarifying the relationship between the healthy situation of residents living temporary housing and the indoor thermal environment and indoor air quality. Therefore questionnaire surveys, interviews and environmental measurement for temporary housing in Sendai city, which is located in Miyagi prefecture, have started the summer of 2011 and were continued to the summer of 2012.
     This paper describes the measured results of indoor temperature and humidity, and occupants' behaviors related to thermal environment in the temporary housing during summer and winter seasons of 2011 and 2012. It was found the associations between indoor temperature profiles and occupants' behavior such as using air conditioner, opening or closing windows and so on from the measured results during summer season. During winter season the indoor temperature was maintained around 20°C during heating time. However after heating equipment was turned off, the indoor temperatures decreased rapidly due to poor thermal performance of building envelope. In addition a numerical analysis revealed the thermal envelope performance and mechanical ventilation system for adequate indoor climate and saving energy. We propose the temporary houses located in cold climatic regions such as Sendai city should have both the building thermal performance closer to the building code for energy conservation and mechanical ventilation system with heat recovery in a living room and bed room.
    Download PDF (1885K)
  • Eiji SAKUMA, Hideyo NIMIYA, Akihiro NAGATA, Shinji HAGIHARA
    2017 Volume 82 Issue 731 Pages 31-41
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     In this study, we focused on the improvement of the additional thermal resistance of windows with shading devices. The measurement of the additional thermal resistance of windows with shading devices, such as blinds or roller screens was conducted for 64 cases under the identical test devices and conditions. The results were further analyzed in terms of gap in the opening, porosity of surface material, ventilation characteristics and emissivity, so as to verify the improved elements of additional thermal resistance.

     (1) To improve additional thermal resistance of the shading devices, the followings are the elements to consider:
      - Make the gaps of the shieling material smaller.
      - Use low emissivity material.
      - Make the heat resistance of the shading devices bigger.

     (2) Venetian blinds can have a better additional thermal resistance by adopting the high degree of shielding and air tightness.

     (3) Roller screens can have a better additional thermal resistance by adopting of low-emissivity screen and side rails.

     (4) Cellular screen has the highest thermal resistance among the shading devices, thanks to cellular structure and its air layer. The performance can be further improved by filling the gaps with side rails.
     The No. 50, the best performance one, achieved an additional thermal resistance of over 0.5[W/m2K].

     (5) Using two layers of shading devices helps the additional thermal resistance improve.

     (6) Measured values are mostly consistent with calculated values by ISO 15099. However, there are some different values between the measurement and the calculation. The desirable difference between the tested and the calculated value is within 10%. The evaluation method taking into account the air permeability (airleakage) of the window with shading devices and the emissivity of shield member is regarded as the future subject to examine, because it is valuable in terms of simplifying the evaluation of the additional thermal resistance of the window with shading devices.

     (7) Even though the improvement of the window's additional thermal resistance by using shading devices is an effective measure, it is regarded as the future subject to examine because the dew condensation possibly appear on the glass surface.
    Download PDF (1374K)
  • Study on draft and ventilation promotion using a ventilation tower in dense urban areas Part 1
    Masaharu TAKIZAWA, Takashi KURABUCHI, Daisuke NARUMI, Toshihiro NONAKA ...
    2017 Volume 82 Issue 731 Pages 43-50
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     1. Introduction
     Even if it is difficult to take advantage of natural ventilation due to ambient conditions, it is beneficial to carry out designing which improves ventilation performances. Several design techniques aimed at promoting ventilation have been available, but have not gained in popularity because they often cause degradation and leak in the roof. In addition, in densely urban areas, it is difficult to predict the prevailing wind direction, and there are possibilities that a wind direction is changed due to rebuilding of the surrounding buildings. Furthermore, due to very narrow building intervals in the residential area of the urban areas, ensuring ventilation amount through the existing wall face-to-face is not easy. This paper focuses on the residential ventilation tower as a measure to address these problems. It aims to realize securing ventilation, which is often difficult through the existing wall window path, as a construction building frame without any use of electricity or moving parts.
     2. Method
     In order to quantitatively evaluate the performance of the ventilation tower, a calculation of ventilation tower size which demonstrates an equivalent airflow resistance value as through the existing wall face openings was carried out using a CFD. In the procedure, a virtual chamber to avoid effects of external wind and inlet conditions into the room was provided on all of the openings, then the flow rate count, α, in the ventilation tower inlet and each opening was calculated. The area of the ventilation tower entrance and ventilation tower opening area, which shows an equivalent ventilation resistance when using α, were calculated and set as Ventilation tower 1 (VT1) and Ventilation tower 2 (VT2) for evaluation in this study.
     3. Result
     The ventilation tower parts of VT1 and VT2 are attached to the roof of the house model, and wind tunnel experiments were carried out. The chamber pressure, the amount of ventilation and a rooftop velocity were measured. The results of the experiment confirmed that the route using the ventilation tower holds about 70% of the ventilation capacity of the existing wall face route without any dependency on the wall opening position and wind direction.
     4. Conclusions
     By creating a mesh for analysis which reproduced the housing model and comparing it with the obtained wind pressure coefficients and amount of ventilation in the experiment, the accuracy of CFD calculation was confirmed. Since the actual phenomena reproducibility of CFD with accuracy was confirmed, we went on to a case study with conditions with buildings in the surrounding area. No significant differences were noted in the case of assumed suburbs with 30% gross building coverage, whereas it was confirmed that the ventilation tower to function effectively in the densely built areas with assumed gross building coverage of 50% and extremely narrow adjacent building spacing conditions.
    Download PDF (1355K)
  • Hyuntae KIM, Shin-ichi TANABE
    2017 Volume 82 Issue 731 Pages 51-57
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     In recent years, SVOC has a high interest as contaminants in house dust in indoor. Specifically, phthalates are more concentrated in house dust than indoor air. The children are higher risk with phthalate concentrated in house dust than adults. We had researched the concentration of SVOC in house dust and air as well as emission rate of SVOC from PVC sheets by using the micro chamber. But, we have not ever investigated that the phthalates contamination in house dust are whether in the substance emitted from PVC sheet to be used in the surveyed house. Therefore, this study was investigated the measurement of SVCO concentration in air and house dust in Korea and to measurement of SVOC emission rate from PVC sheets by using micro chamber.
     As a result, from the air in surveyed houses are detected 2E1H, D6, BHT, DEP, C16, DBP and DEHP but were not detected TBP, TCEP, DBA, TPP and DOA. In this study, the concentration of DBP and DEHP are respectively 0.36-0.67, 0.13-0.56[μg/m3] in surveyed houses. From the house dusts in surveyed houses are detected 2E1H, DEP, C16, TCEP, DBP, TPP, DOA and DEHP. The detection frequency of 2E1H, DBP and DEHP are higher than the other analyzed substances. The average concentration of 2E1H and DBP are respectively 23, 53[μg/g], DEHP is 4225[μg/g] in house dust in the surveyed houses. By using micro chamber, we measured the emission rate of SVOC from PVC sheets that are used in surveyed houses. 2E1H, DEP, C16, DBP, DOA and DEHP were emitted from PVC sheet. 2E1H, DBP and DEHP are emitted from all measured PVC sheets. The emission rate of 2E1H and DBP are respectively 0.35-1.29, 0.12-1.52[μg/m2·h], DEHP is 0.72-14.21[μg/m2·h] from PVC sheets that are used the surveyed houses. On other hand, the D6, BHP, TBP, TCEP, DBA and TPP were not emitted from PVC sheets that are used surveyed houses. The contaminated D6, BHT, TBP, TCEP, DBA and TPP in air and house dusts were not associated with PVC sheets.
     There is no correlation between the concentration of 2E1H, DBP and DEHP in air and the emission rate of 2E1H, DBP and DEHP from PVC sheets. But, in the case of DEHP concentration in house dust, there is correlation between the concentration of DEHP in house dust and the bleed-out rate of DEHP from PVC sheets that is used the surveyed houses.
    Download PDF (705K)
  • Sung-ki SONG
    2017 Volume 82 Issue 731 Pages 59-65
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     This Study from the point of view of flood damage reduction and rainwater harvesting was intended to clarify the water use characteristics and the effect of introduced rainwater utilization system in the university lecture building and also was examined the effective rainwater storage tank volume. It was examined the rainwater utilization rate, tap water replacement rate, cost performance and rain stock height of the rainwater usage grey water system from the three years survey.
     As the results, the amount of annual using water of lecture building from 2011 to 2013 was 16,772-19,269m3/year. The greywater was about 60% of using water in the lecture building, rainwater of the greywater was about 30-40% and the well water was about 60-70% and tap water of greywater was less than 1%. The annual using water for the hand washing-drinking in the lecture building was 38-42% and for the toilet was 35-41% and for the cooling tower was 21-25%, and also the proportion of toilet water in the greywater was about 60%. It was found that lecture building is many used greywater than tap water and the water had been used a lot in the order of the cooling tower and toilet and hand washing.
     The annual rainwater utilization rate of lecture building was 59-84% and it was high in the order of summer 50-90% and winter 61-95% and interim period 72-97%. It found that more than half of the rainwater collected in each year and in each period was used for the greywater. And the annual tap water replacement rate of rainwater and well water were respectively 28-39% and 60-70%. The annual charge of water and sewerage was reduced by about 40% because the rainwater usage greywater system of lecture building have been used almost 100% of the rain water and well water. The recovery year of the initial cost by reducing the annual water and sewerage charge in consideration of the maintenance inspection cost was about 7.2 years. If only the water and tap water was priority use in cooling towers, the recovery of the initial cost was about 17.2 years.
     The basic rain stock height of lecture building which is rain stock performance was about 56mm, since the flood control rain stock height and water utilization rain stock height were respestively 20.3mm and 35.4mm. Therefore, it was found that in order to satisfy the basic rain stock height 100mm in lecture building was necessary providing the new storage tank for flood control of about 44mm, or increasing the rainwater storage tank to 2.3 times.
     Furthermore, according to the results of simulation using the gray water usage data of the lecture building, When the rainwater storage tank be increased to up to 600m3, rainwater utilization rate and tap water replacement rate was respectively increased to about 90% and 40%. It was found that rainwater utilization rate of university lecture building of long holiday period and irregular water use was smaller than the office building and the rainwater utilization rate was difficult to achieve more than 90%.
    Download PDF (5578K)
  • Yusuke MATSUO, Koki KIKUTA, Masaya SAITO, Hirofumi HAYAMA
    2017 Volume 82 Issue 731 Pages 67-76
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     Introduction
     In Hokkaido, passive ventilation system has been developed as the distinctive technology in cold region. It is essential to reduce the use of fossil fuel for space heating, therefore the planning of space heating system in high performance houses is required significant improvement of insulation as well as airtight. Over the past decades, the use of woody biomass resources for space heating and hot water supply system has been increased mainly in the mountainous areas in Japan. In some of these areas, there are “community heating system” as a small district heating system with small biomass boiler, which are consisted of some residential houses, city halls, and other public facilities. This is because woody biomass resources which can be obtained in the neighborhood mountain can contribute to reduce the use of fossil fuel and electricity. In this study from these backgrounds, we focused on how to design high-efficiency community heating system using woody biomass which supplies thermal energy to a group of high performance passive ventilation houses in a town of Hokkaido.

     Analytical model of supply and demand sides in community heating system
     In the past studies regarding the district heating system, a size of the heating demand has been given as the numerical values of the basic unit about the energy use according to the building types. In this study, annual heating demands of communities were assumed based on the insulation performance of houses and the living activities of households. Three types of community: new-region, mixed-region, and old-region were assumed from the combinations of three different insulation levels of houses. New-region is composed of only high insulated houses, mixed-region is mixed the low insulated with the high insulated houses, and old-region is mainly composed of low insulated houses. Annual heating demands per a household (a ratio of load levelling) were calculated 11 MWh/year (37%) in new-region, 16 MWh/year (30%) in mixed-region, and 20 MWh/year (25%) in old-region.
     On the other hand, a size of the supply side system as a biomass boiler, pumps and pipes was assumed to satisfy the peak of heating demands of the communities. The energy efficiency of a biomass boiler of 85%, the insulation thickness of the polyethylene pipe lines of 30mm, and the flow velocity of hot water of 1.0 to 2.0 m/s were assumed.

     Energy and exergy analysis of community heating system
     From the results of analysis, it was found that SCOP of community heating system tends to decrease gradually by the number of households increases despite the difference in new-region, mixed-region, and old-region. The reason is due to the fact that pump load gets larger with increasing speed. In the case of 20 to 100 households, SCOP is highest in new-region, followed in order by mixed-region and old-region. SCOP in all cases of community heating system is higher than that of individual heating system. In addition, the community heating system composed of the residential houses is required a combination with some public buildings such as office school, hospital, and day-service center for the elderly which have large heating demand in the daytime. From the exergy analysis in case of 40 households, total input exergy for the community heating system were 1.1 to 1.4 times larger than that for individual heating system. However, 72% of this input exergy of the community heating system was equivalent to the chemical exergy within woody biomass which can be obtained in the neighborhood.
    Download PDF (846K)
  • Takashi AKIMOTO, Reiji SUDA
    2017 Volume 82 Issue 731 Pages 77-86
    Published: 2017
    Released on J-STAGE: January 30, 2017
    JOURNAL FREE ACCESS
     This paper investigated and proposed a new running-cost subsidy system utilizing the environmental value of solar thermal in order to promote expansion of solar thermal use. The program is not a conventional subsidy program for the initial cost but a new program of providing a subsidy for running a system while confirming user status. It is for the national or local government to provide incentives in accordance with the environmental value based on the amount of solar thermal use. The similar scheme to the proposed system, there is Green Thermal Certificate system in Japan, Australia REC system and UK RHI system, and we discussed the common points and differences between the proposed system and these similar systems. Feature of the proposed system is, by the conversion factor that defines for each measurement method is to convert the amount of solar thermal use to the environmental value amount, and the user can select how to measure.
     It was verified as NEDO research project for the accuracy of the measurement method. This project has adopted specified measuring instruments as reference and conducted experimental study using actual or artificial loads at residential houses and condominiums in a total of 101 fields across the country. The study set out the target values of error within ±10% for built-in simple calorimeters and external simple calorimeters and less than ±20% for deeming measurement. The study has confirmed that both built-in and external simple calorimeters give high precision in measurement: the average errors of the annual solar heat consumption volumes stood at -1.0% and +2.6%, respectively. As for deeming measurement, the annual solar heat consumption volume has been calculated with the EESLISM simulation program. The calculation has used as parameters HASP meteorological data in the regions with apparatus installed, characteristic values of equipment, expected hot water supply loads and other elements. As a result, the average error of the annual solar heat consumption volumes was -12.2%, which has also satisfied the targeted error range.
     The subsidy per MJ for the standard cost scenario of a domestic solar hot water system (modified 3.0 to 3.5 people household, solar collector area: 4m2, and hot water tank: 200L) is 5.50 yen. It is based on the national average amount of solar thermal use of simulation calculation (5,647MJ/annual) under the condition of hot water demand M2 (400L/daily hot water supply) at 20 sample places in Japan. The amount of subsidy by measurement method is approx. 310,000 yen, 280,000 yen, 260,000 yen and 220,000 yen when it is measured with a specified measuring instrument, external simple calorimeter, built-in simple calorimeter and deeming measurement, respectively. The subsidy per MJ under a similar UK RHI system is 6.35 yen and its amount is approx. 400,000 yen (four-people household, 4m2 of solar collector area, and 250L of hot water tank) and thus the proposed system is not difficult even slight difference in the estimation conditions is taken into consideration.
     The basic national energy plan has a goal of requiring new houses and buildings to comply with energy-efficiency standards in stages. Solar thermal utilization is essential to realize the government goal and the program will contribute to its realization as one of measures.
    Download PDF (2067K)
feedback
Top