In pursuit of a sustainable society, office buildings need to be designed to not only improve environmental performance, like in energy efficient buildings, but also the health and intellectual productivity of employees. Further, to make up for the shrinking labor force caused by the decline in birth rate and the aging society, and the limited working hours caused by work-style reforms, it is necessary to improve the quality of individual productivity. Designing offices considering employees’ design preferences could enhance individual productivity. Therefore, the present study conducted a quantitative comparison of an environment’s efficiency determinants and examined their influence on productivity across distinct design preferences. This was done to ascertain which office environmental factors and functions are most suitable according to office workers’ design preference types (Fig.1 and 2).

Accordingly, 2,684 individuals completed the survey in March 2019 (Table 1). Questionnaire items evaluated their satisfaction with the current office environment a 5-point scale (Table 2 and 3). Data were used to develop the “environment–intellectual productivity” model using structural equation modeling (Fig.3 and Table 4). Furthermore, a multi-group analysis was performed to compare different preference types and quantify their effects on each path coefficient. To compare path coefficients, factor loadings were constrained to be equal across design preference types, except for paths pointing to the observable variables of “concentration,” “motivation,” and “intellectual productivity.” Additionally, critical ratios for differences were used to compare path coefficients across groups (Table 5 and 6).

The environment–intelligent productivity model developed from the covariance structural analysis revealed that environmental factors influenced intellectual productivity through “behaviors related to intellectual productivity” and “stress and motivation” (Fig.3). Models on design preference types indicated that distinctive office design preferences led to varying degrees of influence of environmental factors on relaxation and communication. Further, significance tests of difference revealed that, in turn, this affected the level of difficulty experienced in addressing work pressures. Ultimately, these environmental determinants influenced intellectual productivity to varying degrees (Fig.4). The usual features that characterized each type of model were as follows: With reference to preference characteristics obtained from Type 1 and Type 3 office photos¹³⁾, the common characteristic was that participants preferred “G2 Conservative” and do not prefer “G3 Playful”, while their preference for “G1 Open and pacious” differed. These findings suggested that Type 1 individuals may be more sensitive to factors related to concentration, while Type 3 individuals may be more sensitive to those related to creative activities. These differences explain their differing preferences for an open environment. As for Type 2 and Type 4 participants, both commonly preferred G1 and G3, while their preferences for “G2 Conservative–typical” and “G2 Conservative–booth” differed¹³⁾. These findings suggested that Type 2 individuals tended to prefer an office space that was relaxing and inspiring, while Type 4 individuals tended to prefer an environment that reduces pressure and helps them achieve peace of mind. This explains why these two types of office workers had different preferences for booth-type offices.

Our proposed approach would enable us to design personalized office environments that incorporate individual preferences. t aims to increase employees’ satisfaction with their office environment, and in turn optimize the individual strengths and maintain intellectual integration among employees.

1. Background and objective

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, 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. Therefore, it is difficult to analyze individual difference of each object. In this paper, methodology for analyzing individual differences of each object in individual scales method was studied and proposed.

2. Methodology of analysis

For the above purpose, the application method of "partial score" used in the analysis method called MFA (Multiple

Factor Analysis) was discussed. And the following method was proposed.

1) Exclude subjects with low correlation between partial score and global score (principal component score).

2) Use "standardized partial score" to analyze individual differences for each object.

3) Correcting techniques for "ipsative data" may be necessary when analyzing individual or group differences between multiple objects.

In addition, using "HCA (Hierarchical Component Analysis)" as the analysis method is expected to improve the performance of partial scores.

3. Case study

As a case study, a survey on positioning analysis for dental clinic was conducted. The background, purpose and method of this survey were described.

4. Analysis and discussion

PCA, MFA (Block-based PCA), and HCA were applied to the case study data, and the following results were obtained.

1) The output principal component scores did not differ between the methods.

2) HCA was the best in the performance of statistical tests for partial scores. This shows that reliability of partial score by HCA is higher than that of other methods.

3) It was found that the positioning of the dental clinic is different between those who are positive for visiting dental clinic and those who are not.

5. Consideration on Methodology of Analysis

Based on the results of analysis as a case study, methodology was further considered. First, as a criterion to exclude subjects with low correlation between partial score and global score , “R-square≧0.4” was proposed. Next, how to use FA and PCA properly was considered, and necessity of correcting techniques for "ipsative data" was discussed.

6. Future tasks and prospects

The future tasks are to apply the proposed method to many cases. And, using partial scores, it seems possible to analyze individual scale method data, including different objects for each person. It is also a future task to consider this method.

Natural disasters that had recently happened in Japan, including Great East Japan Earthquake in 2011, destroyed social infrastructure especially electricity systems for more than several months. During this period, electric supply tremendously decreases and caused many problems to emergency response, lifeline infrastructure management, life supporting related activities in hospitals and refugee accommodations and also government administrative business. In order to sustain these basic activities, we need minimal lighting systems to facilitate workers in offices maintaining these activities. However, most of lighting research on emergency, Boyce et al., Akizuki among others, concentrate on emergency escape lighting system. Mochizuki et al. studied the impacts of shortage of electricity on office lighting environment during Great East Japan Earthquake aftermath. To our knowledge, there are no studies analyzing the minimum lighting system required in offices during emergency period. Appropriate assessment of visual environment for business in disaster effected areas is required. Thus, the purpose of this paper is to develop a virtual reality simulation system (VRS) which can provide real focal-ambient lighting environment for workers in the office and to find the minimum lighting environment required to continue working for more than 10 days during emergencies. 2400 observations from 20 participants (9 students and 11 office workers, 9 female and 11 male) assessing 30 VR scenes on 4 business continuing periods (1 day, 3 days, 10 days, over 10 days) were obtained in the experiment. We found the following results from the experiment:

1. VRS can provide focal-ambient lighting environment for experiment participants more realistically than other devices. It has high 96.7% accuracy representation percentage of real environment luminance-chromaticity values of VR scenes and provides 360 degrees experience of real visual environment at 3 degrees of freedom to participants.

2. Minimum lighting on working surfaces can be as small as 75 lux for more than 10 days office work in emergency.

3. Ambient lighting is strongly required to keep comfortable room brightness and focal ambient lighting system for the workers. At working surface illuminance of 75 lux, 100% of participants can continue to work for more than 10 days with ambient light and only 85% of participants can continue to work for 10 days without ambient light.

4. There may exist some possibilities that student participants of experiments may not have strong tolerance against less lighting than office workers. Office workers can work for 10 days with 15 lux on working surface while students require twice this illuminance of 30 lux. i.e. we need to study more about the effects of participants’ attributes on experiment results.

5. 360 degrees Brightness Estimation Image can be used to assess how much ambient and focal brightness is required in the given visual environment.

6. Ambient visual environment is confirmed to be strongly correlated with how much light is available in desk surroundings, walls, and ceilings and not with horizontal surfaces such as floor discussed in the literature.

In the human living, it is now necessary to consider conditions that combine both lighting conditions and interior conditions. However, there are few studies that combine light color and interior color. Then, we performed an impression evaluation experiment in a full-scale space assumed an office space (Exp.1) and a relaxed space (Exp.2) to get insights that are how the combination of light color and interior color affects the impression of the space and what combination is preferable for humans and conditions accompanying it.

Assuming a room with a white wall that is partly partitioned by chromatic partitions, we will conduct full-scale space experiments with a set of desk and chair placed in the real space. In Exp.1, there are 24 conditions combined the light source color 2 conditions, desk top illuminance 2 conditions, interior color 6 conditions, and in Exp.2, there are 20 conditions combined the light source color 2 conditions, desk top illuminance 2 conditions, interior color 5 conditions.

As a condition, each subject was randomly presented. The impression of the space was answered by the 7-step SD method, and the evaluation items were 10 pairs in Exp.1 and 12 pairs in Exp.2.

We analyzed the experimental results by summarizing the two experimental results and examining the relationship between the setting factors and each impression evaluation item regarding spatial impression.

As a result, it was found that subjects preferred low-saturation colors in many impression evaluation items regardless of use and it was necessary to consider a saturation when constructing a space with colors. In addition, when considering the combination of light color and interior color, the combination of the same colors was highly evaluated in all the items in which the interaction was observed. So we considered that the combination of the same colors is generally better than the opposite colors in case of a space. We could also see the difference in impression due to the difference in the use of the room by comparing the two experiments. The image of each space seems to affect the impression evaluation, especially [calmness] and [enjoyment] in the interaction of the experimental condition and the interior color. The color becomes close to white, the higher the rating was in the office space, and the color becomes in the range from warm colors to achromatic colors, the higher the rating was in the relaxed space.

When the two experiments were compared, there was no effect on the combination of light color and interior color depending on the conditions and it was generally considered that the combination of the same colors is preferable. On the other hand, it was also found that there are some evaluation items that affect the impression due to the color temperature and the interior color because of the conditions. It can be presumed that psychological factors for the use of each room affect the sense of brightness, so it is considered that there is a relationship between the image and color temperature of each use.

As natural ventilation significantly contributes to energy savings and enhances comfort, it has been adopted in recent times in many buildings. However, there may be issue with natural ventilation such as the occurrence of low temperature environment; hence, the natural ventilation rate must be set to appropriate value. In the previous study, the authors had proposed a new simulation tool that can be estimate the effect of natural ventilation control that includes the lower limit of room temperature by adjusting the “opening ratio”. However, it is difficult to vary the opening ratio continuously. Thus, the authors notice that there is a logical possibility that the opening ratio is used to set an appropriate effective opening area of the natural ventilation. In this paper, the authors examined an appropriate method for setting the effective opening area of natural ventilation opening and the lower limit of outdoor temperature using the lower limit of room temperature control calculator.

First, as an example of the simulation results obtained by adjusting the opening ratio, the time variation diagram for the representative day, the air change rate, and the room temperature are presented. Although the air change rate is reduced by adjusting the opening ratio, it is possible to reduce the duration for which the lower limit of room temperature is at the set value or less. Furthermore, the authors performed calculations for 20 cases to understand the factors that influence the value of the opening ratio. It was found that the internal heat gain, the lower limit of the set value of room temperature and the number of floors influence the value of the opening ratio, and that the lower limit of the set value of room temperature has a significant influence. The details of this calculation are given in chapter 4. Next, as it is difficult to vary the opening ratio continuously in an actual building, the effective opening area of the natural ventilation opening and the method of setting the lower limit of outdoor temperature were examined to obtain the same result as in the case when the calculator with adjusting the opening ratio. The authors presented the correlation between the outdoor temperature and opening ratio from the simulation results obtained in chapter 4, and studied the method of setting the effective opening area of the natural ventilation opening and the lower limit of outdoor temperature; thus, it was possible to reduce the duration for which the temperature was below the lower limit of the set value of room temperature. The details of this calculation are given in first half of chapter 5.

Finally, the method of setting the effective opening area of the natural ventilation opening, depending on the floor, was studied to reduce the difference between the air change rates in different floors. By adopting a setting method that increases the effective opening area of the natural ventilation opening toward the upper floor, the difference between the air change rates in different floors could be reduced, and the duration for which the temperature is below the lower limit of the set value of room temperature setting could be reduced.

In future study, the authors would like to examine the natural ventilation design method under the condition when wind pressure is applied.

At present in Japan, non-wood type low-rise housing with excellent aseismatic performance and durability is on the increase; especially lightweight steel frame low-rise housing using Autoclaved Lightweight-aerated Concrete (ALC) panels is becoming popular. The objective of this study is to develop a drainage system applicable to such housing and propose a planning/design method thereof.

In this report, the objective has been to evaluate the performance of a horizontal fixture branch system which is installed in a house for receiving water drained from sanitary fixtures in the house, and to obtain knowledge that contributes to planning and designing. A comprehensive evaluation of drainage performance, ventilation performance and carrying performance was carried out on a commonly used “under-beam horizontal fixture branch system” (conventional horizontal fixture branch system) having a large diameter (100A) and a “through-beam horizontal fixture branch system” (proposed system) having a small diameter (75A) and excellent workability, each of which was installed in the house and to which a toilet, a kitchen sink, a washbasin, a bathtub and washing machine were connected and drainage loads were applied. The following knowledge has been obtained as a result:

(1) In the conventional horizontal fixture branch system, even in the case of merged wastewater generated from the five fixtures, the in-pipe pressure remains in a range of 250 Pa to －120 Pa, i.e., within the SHASE-S 218 reference value range of ±400 Pa by providing ventilation by disposing a vent valve (50A) at a position upstream of the horizontal fixture branch.

(2) In (1), when ventilation was provided by adding another vent valve at a position downstream of the horizontal fixture branch, the effect of the upstream ventilation was still greater and there was no significant pressure relaxation. Therefore, placing a vent valve on the upstream side is optimally effective.

(3) In the through-beam horizontal fixture branch system, in the case of merged wastewater generated by the five fixtures, the in-pipe pressure was significant in a range of -550 Pa to 410 Pa, i.e., exceeding the reference value range of ±400 Pa, even with a vent valve disposed at a position upstream of the horizontal fixture branch.

(4) Despite the finding in (3), in the case where drainage loads were applied from 2-3 fixtures, which is more realistic, the fluctuation in pressure was －130 Pa to 200 Pa, i.e., within the reference value range, indicating applicability. Accordingly, it is considered that in order to accommodate the case where drainage water is generated from more than three fixtures, the conventional horizontal fixture branch system with a large diameter will be required.

(5) With regard to the carrying performance of the two systems, using substitute waste, merged wastewater temporarily became stagnant 4,000-5,000 mm from the most upstream side. However, follow-up draining got the flow going down the drainage stack, and into and out of the house drain, indicating no hindrance caused.

In recent years, Thermally Activated Building System (TABS) has been introduced in Japan as an air conditioning system that achieves both comfort and energy saving. TABS in which the building frame (mainly the concrete slab) is used as a component for radiating and storing heat have been installed mainly in Europe since the late 1990s. In recent years, the number of cases of TABS being installed in office buildings in Japan has increased. TABS offers high energy savings, thermal comfort, and peak shift performance by utilizing the heat capacity of the building. However, it is difficult to control TABS because the thermal response of the ceiling surface temperature is slow due to the large thermal mass. Therefore, Model Predictive Control (MPC), that determines the current value of the optimal manipulated variable pattern while predicting the behavior of a future controlled variable, is attracting attention.

On the other hand, by combining MPC and artificial intelligence (AI) technology, there is a possibility to achieve further energy savings while maintaining control performance and improve durability by reducing the use frequency of air conditioning equipment, although there are few reports of social implementation, especially its application to engineering problems.

In this study, we proposed a control method that incorporates Sparse Modeling into MPC as optimal control method for an air conditioning system with large thermal mass. Moreover, we showed the effectiveness of this method by comparing conventional control method using coupled analysis of CFD analysis integrating general-purpose control simulator.

The following results were obtained:

1. The proposed method has achieved sparseness of water flow rate (energy saving by expanding the zero range) while satisfying the ceiling surface temperature within a comfortable range.

2. It was confirmed that the proposed method reduced the operating time of TABS by about 14 hours and the integrated water flow rate by 39% while controlling the ceiling surface temperature.

3. It was confirmed that not only the sensor location but also the working space satisfied the comfortable range at 1.1m above the floor.

INTRODUCTION

Zero energy house (ZEH) is expected to have a significant initial cost increase compared to conventional houses. In this study, the purpose is to examine the life-cycle cost and economy of ZEH. Calculate the construction costs for ZEH, initial costs such as photovoltaic power generation, the power purchase fee from the electric power company, and the power sales fee for surplus power generation. Similarly, the running cost and initial cost for the conventional house are calculated. By clarifying the life-cycle cost that combines the running cost and the initial cost of the ZEH model and the conventional model. The increase of the initial cost and the reduction of the running cost by the energy saving effect by ZEH are examined.

RESEARCH METHODS

The analysis model is a standard housing model of the Architectural Institute of Japan. The model is all electrified houses. The analysis area is 11 major cities. The average U-value is 0.6 W / (m² · K) for the ZEH model (0.4 W / (m² · K) in Sapporo), the conventional model is 1.2 W / (m² · K) (0.8 W / (m² · K) in Sapporo). The annual air conditioning load calculation uses the thermal load simulation software TRNSYS ver.15 to calculate the heating / cooling load of each room for the ZEH and the conventional model in each region. Using the solar radiation from the AMeDAS meteorological data from the Architectural Institute of Japan (standard year), calculate the power generation amount per solar cell in each region. The conventional model uses the annual electricity bill as the running cost.

In the ZEH model, the annual running cost is the amount obtained by subtracting the annual electricity sales fee of solar power generation from the annual electricity purchase fee.In the ZEH model, the solar cell module, power conditioner, and installation work cost are required for initial cost and equipment replacement. In addition, 70 [10,000 yen / unit] is subtracted from the initial cost as a subsidy for ZEH. The service life of the solar power generation system is assumed to be 20 years, and once every 20 years, equipment replacement costs are recorded as running costs. The running cost is added to the initial cost, the life-cycle cost from the time of construction is calculated for each house. The number of years in which the life-cycle cost of the conventional model exceeds the life-cycle cost of the ZEH model is the ZEH investment payback period.

RESULTS

The annual power consumption is reduced by about 6% to 26% when the UA value is halved.Investment payback period of ZEH exceeds 25 years in 8 cities except Kobe, Kochi and Fukuoka in case A (hot water supply: COP2, air conditioning: intermittent use). Case C (air conditioning: continuous use) tends to have a shorter investment payback period compared to case A without Kobe, Kochi and Fukuoka. One of the factors is that the benefits of preventive diseases (non-energy benefits) were obtained by using continuous air conditioning. In case D (hot water supply: COP3, air conditioning: continuous use), the investment payback period is the shortest in the analysis case in any region. In Kobe, Kochi and Fukuoka, the payback period is about 10 years. In case D, the maximum investment payback period is about 27 years.

The non-uniformity of building height has been attracting considerable attention because the wind above the urban area blows down to the ground level, thereby improving the poor ventilation in urban districts. In a previous study, (part 1 of this study), it was reported that non-uniformity of building height draws the wind above the urban district to the pedestrian-level and improves the outdoor ventilation even in highly dense urban districts. Additionally, it increases the aerodynamic resistance of buildings and decreases streamwise momentum transport of air to the leeward side of the urban district.

In this study, large-eddy simulations (LESs) were applied to the flow fields in two districts consisting of rectangular buildings with uniform and non-uniform heights. The streamwise distributions of total kinetic energy transport and the energy dissipation rates from the windward to leeward sides of the urban area in the two city models were calculated from numerical data provided by LES computations, to investigate the influence of aerodynamic resistance of buildings on the dissipation of total kinetic energy (adverse effect on the wind environment in the leeward side of the focused urban district). Consequently, in the urban area, energy dissipation occurred at an approximately constant rate, and the total kinetic energy transport decreased constantly with energy dissipation (Fig. 10). As shown in Fig. 11, the decrease in total kinetic energy transport in the case of non-uniform building height was approximately 1.5 times of that in the case of uniform building height.

To clarify the influence of all the terms in the equations of total, mean, and turbulent kinetic energy transport on the transportation and dissipation of kinetic energy when the wind above the urban area blows down to the ground level, the vertical distributions of the balances of each term in the transport equations of the total, mean, and turbulent kinetic energies were analyzed. As shown in Fig. 13, above the urban area, the transportation of total kinetic energy by advection and diffusion showed positive values, and the dissipation and pressure terms indicated negative values. The peak of transportation and dissipation of total kinetic energy occurred at the maximum height of the buildings in urban districts, and these absolute values increased due to the non-uniformity of building height. In Fig. 14, the mean kinetic energy was supplied owing to the advection and diffusion terms, which was then dissipated through energy transport from mean kinetic energy to turbulent kinetic energy, －Pk. The－Pk in Case Non-uniform was larger than that in Case Uniform. There was only a little energy dissipation of the mean kinetic energy in both cases. As shown in Fig. 15, the distribution of the dissipation term is nearly symmetrical to that of the production term of the turbulent kinetic energy, Pk. As shown in Figs. 7 and 16, the region where the dissipation term of turbulent kinetic energy is generally large corresponds to the region where Pk is large. This indicates that in the region where turbulent kinetic energy is produced, the mean kinetic energy is converted into turbulent kinetic energy, and then the turbulent kinetic energy is dissipated in the same region.

Since 2011, this research group has been analyzing energy consumption based on data from Home Energy Management Systems. HEMS data of about 50,000 houses were collected and analyzed. The composition of the HEMS data was clarified. Energy balance such as power generation and household consumption was clarified for the purpose of promoting energy saving of new houses and existing houses. The object of this analysis is a monogenesis zone of 6 regions, and the floor area is 100 ～ 140m2. Photovoltaic power generation is classified into (S) of average capacity 4,6,8,10kW and storage battery 5kWh or less, (M) of 5.1 ～ 8 kWh, and (L) of 8.1kWh or more, and the analysis period is 1 years from April, 2018 to March, 2019, and the sample number is 829 houses without data loss. As a general feature, as battery capacity increases, annual electricity purchases decrease and household consumption (including charging) increases. Generally, the self-sufficiency rate is improved as PV capacity and BES capacity are larger. As the number of families increases, energy consumption also tends to increase. Therefore, the energy Self-Sufficiency rate tends to decrease, and the self-sufficiency rate tends to increase as solar power generation capacity increases. The self-sufficiency rate generally tends to rise as the construction year becomes new.

In addition, since the total consumption also increases as the floor area increases, the self-sufficiency is on a declining trend for all types of photovoltaic power generation capacity. When all room air conditioners are compared with air conditioners, the self-sufficiency rate is reversed to DCAC, and DAC becomes higher as PV capacity increases. The buildings constructed in 2017, when the ZEH policy was promoted, were improved in heat insulation performance, facility performance, and Self-Sufficiency Rate. In order to improve the Self-Sufficiency Ratio, it is important not only to increase the capacity of photovoltaic power generation and storage batteries but also to reduce the total power consumption. It is expected that the Self-Sufficiency Rate will be further improved by the Heat Pump type Water Heater and the surplus electric power utilization of the electric automobile. In the future research, the data quantity will increase further, and the building data after 2018 will be also available.

In the future, it is important to continue to analyze and publish data on snow-covered cold regions and data on further increases in ZEH rates, and to demonstrate the effectiveness of ZEH, a self-sufficient housing model, and to accelerate its popularization. It is expected that the Self-sufficiency rate will be further improved by the introduction of the Service and the mechanism which carry out the operation method of Eco Cute, air conditioning of all rooms, and surplus electric power utilization of electric vehicles without the user's trouble. In future research, the amount of data will increase further, and building data will be available after 2018. It is important to continue to analyze and disclose data on snow and cold regions, as well as data on which the ZEH rate has increased further, and to prove the effectiveness of ZEH, a Self-Sufficient housing model, and to accelerate its dissemination.