Office Buildings In Tokyo Research Articles

Economic benefits of the effects of office environment on perceived work efficiency and presenteeism

As hubs of intellectual activity, offices are expected to promote work efficiency and support worker health. Many studies have analyzed the relationship of the office environment with work efficiency and the health of workers. However, few studies have compared the effects of various elements of the office environment on these outcomes and their economic benefits. To address this limitation, this study investigated the impact of various environmental elements on both work efficiency and health, and analyzed the economic benefits of optimizing these elements in office spaces. The impacts of each element of the office environment on work efficiency and worker health were analyzed for 1644 workers in 29 office buildings in Tokyo, Japan. Economic benefits were estimated by comparing perceived work efficiency to an ideal office and presenteeism to the absence of health-related barriers. The results showed that the office interior and furnishings provided the largest estimated economic benefits, followed by overall building sanitation and HVAC airflow. These elements produced economic benefits associated with high perceived work efficiency. The largest estimated economic benefits associated with low presenteeism was from desk lighting, which was the fourth largest economic benefit overall. The results suggest that healthy offices require not only improvements but also the removal of negative elements. These findings are expected to contribute to the realization of comfortable, healthy offices.

Correlations between building performances and design parameters of double‐skin facade utilizing perforated screen

AbstractThis study investigates the effect of a perforated sheet combined with a double‐skin facade (DSPF) by varying the important building parameters, such as perforation percentage, facade orientation, and the thickness of the double‐skin facade (DSF). This study determines the energy‐saving, natural ventilation, and daylight performance of an office building in Tokyo, Japan by conducting simulations. This study discovers that the DSPF thickness does not influence the performances much and the DSPF thickness of 0.5 m is recommended. For daylighting, the system with the 40% perforation percentage on the south and 10% perforation percentage on the west is the best case of daylight access without disturbing glare in the particular view of this study. To balance natural ventilation and daylight when installing perforated screens, this research demonstrated the net heat removal in spring when the perforated percentage of 50% on the south and 30% on the west is recommended. In autumn, the net heat removal when the perforated percentage of 10% on the south and 30% on the west is recommended. This research demonstrated that the total net heat removal when the perforated percentage of 10% on the south and 30% on the west are recommended for removing heat throughout a year.

Improvement of Phased Evacuation Scenario based on Analyses of Pedestrian Flow in Stairwell during Drills in High-rise Office Building

In Japan, a standard on the minimum capacity of escape staircases according to occupant load is not regulated except for some building uses. Therefore, staircases can't contain all occupants in an emergency case. Even though they attempt to evacuate building, most of them must wait in staircases and/or corridors for a long time, which must cause heavy congestion. Thereby, the phased-evacuation method has been recommended for preventing it, but there is no specific method or standard related to the strategic plan. In order to improve a sequential evacuation plan, evacuation drills were conducted at a high-rise office building in Tokyo, and year by year the scenarios of evacuation guidance were advanced a lot better. However, having several unexpected reasons or behaviors; not following broadcasting order, walking slow for chatting and having disability, some drills hadn't been carried out as predicted. The purpose of this study is to consider the real-time control method of changing the scenario for providing guidance flexibly in a sequential evacuation using security device such as attendance management system and security cameras in the future.

Alternative Land‐Price Indexes for Commercial Properties in Tokyo

The System of National Accounts (SNA) requires separate estimates for the land and structure components of a commercial property. Using transactions data for the sales of office buildings in Tokyo, a hedonic regression model (the “builder’s model”) was estimated and this model generated an overall property price index as well as subindexes for the land and structure components of the office buildings. The builder’s model was also estimated using appraisal data on office building real estate investment trusts (REITs) for Tokyo. These hedonic regression models also generated estimates for net depreciation rates, which can be compared. Finally, the Japanese government constructs annual official land prices for commercial properties based on appraised values. The paper compares these official land prices with the land prices generated by the hedonic regression models based on transactions data and on REIT data. The results reveal that commercial property indexes based on appraisal and assessment prices lag behind the indexes based on transaction prices.

Ultraviolet Radiation on an Urban Street with High-Rise Buildings in Asia

Excessive exposure to UVR is known to cause skin cancer, cataracts, and damage to the DNA1,2. In recent years, many skyscrapers have been built in urban areas, and these buildings use energy conscious glasses such as low-e glass and heat reflecting glass to block heat from the outside. Furthermore, unlike common glass, some high-performance glasses reflect not only infrared radiation but also UVR. Therefore, urban streets flanked with office buildings might induce a condition of high UVR exposure. In this paper, the UVR environment of urban streets with office buildings in Tokyo and Singapore was observed. The amount of UVR exposure at a street block was investigated by determining the radiant quantities of the radiation reflected from four directions using UVR and visible radiation sensors. In the results, UVR correlates roughly with sky view factor. However, the coefficient of variation among UV radiation values for the four directions was lower than that for visible radiation because UVR has a high scattering property3 Therefore, it is important to reduce the doses of UVR on urban streets by implementing strategies such as shielding with plant canopies, shade structures attached to building facades, and grass.

Condensation Risk Due to Variations in Airtightness and Thermal Insulation of an Office Building in Warm and Wet Climate

Condensation in a building encourages microbial growth, which can have an adverse effect on the health of occupants. Furthermore, it induces the deterioration of the building. To prevent problems caused by condensation, from the design step of a building, predictions of the spatial, temporal and causation for condensation occurrences are necessary. By using TRNSYS simulation coupled with TRNFLOW, condensation assessment of an entire office building in Tokyo, Japan, was conducted throughout the year, including when the air-conditioning system was not operated, by considering the absorption-desorption properties of the building materials and papers in the office and the airflow within the entire building. It was found that most of the condensation occurred during winter and was observed mainly in the non-air-conditioned core parts, especially the topmost floor. Additional analyses, which identified the effect of variations in the thermal insulation of the external walls, roof and windows and the airtightness of the windows on condensation, showed that the lower airtightness of windows resulted in decreased condensation risks, and condensation within the building was suppressed completely when the thermal insulation material thickness of the external walls was greater than 75 mm, that of the roof was greater than 105 mm and the windows had triple float glass.

Effect of facade components on energy efficiency in office buildings

Properties of facade materials should be considered to determine which of them strongly affect building energy performance, regardless of the building shapes, scales, ideal locations, and building types, and thus may be able to promote energy efficiency in buildings. In this study, the effects of four fundamental facade properties related to the energy efficiency of office buildings in Tokyo, Japan, were investigated with the purpose of reducing the heating and cooling energy demands. Some fundamental design factors such as volume and shape were also considered. It was found that the reduction in both the solar heat gain coefficient and window U-value and increase in the solar reflectance of the opaque parts are promising measures for reducing the energy demand. Conversely, the reduction in the U-value of the opaque parts decreased the heating energy demand, and this was accompanied by an increase in the cooling energy demand in some cases because the total energy demands were predominantly for cooling. The above-mentioned promising measures for reducing building energy demands are thus recommended for use, and an appropriate U-value should be applied to the opaque parts based on careful considerations. This study provides some fundamental ideas to adjust the facade properties of buildings.

放射空調設備とスプリンクラー設備の配管兼用システムの性能確認試験

Dual-purpose sprinkler water piping system which is combined with radiant air conditioning system has been developed. The system is applied to the high-rise office building in Tokyo and certified as the “special fire defense equipment” according to the Fire Service Act of Japan. Heat resistance test of the equipment and system operation test were carried out. As the result of the tests, it is confirmed that the system has the performance which is equivalent to the sprinkler system.

Thermal comfort and productivity in offices under mandatory electricity savings after the Great East Japan earthquake

Little is known of workers’ comfort and productivity under special conditions, particularly after large disasters. The Great East Japan Earthquake in 2011 caused enormous damage, leading to a 15% peak-power reduction to address power shortages. We investigated occupants’ comfort and productivity in five office buildings in Tokyo during the summer season under mandatory electricity savings implemented after the earthquake. We changed the temperature, illumination and ventilation rate settings to investigate their effects on thermal comfort, productivity and energy levels. Occupants were more receptive towards decreased illumination than increased temperature. Awareness of power savings was increased, with more than 90% of people accepting the poor indoor environment in the light of recent events. Set-point temperature and clothing recommendations made by the Super Cool Biz campaign were followed in most offices. However, self-estimated productivity was 6.6% lower than the previous summer. Thus, electricity-saving strategies that do not affect productivity are required.

Thermal comfort in offices in summer: Findings from a field study under the ‘setsuden’ conditions in Tokyo, Japan

Post Fukushima disaster, the energy consumption perspective in Japan has changed. It initiated unprecedented exercises towards energy saving and produced interesting results. These included the ‘setsuden (energy saving)’ campaigns, which promoted the minimum indoor temperature setting of 28 °C in summer. However, there is no scientific basis for this recommendation. Japan does not have adaptive comfort standards and the ASHRAE standard-55 does not include the data from the land of the rising sun. In this context, we conducted a thermal comfort field study in four office buildings in Tokyo for three months in summer 2012. We measured all the four environmental and the two personal variables. Through a paper based field survey, we interviewed 435 occupants who returned 2402 questionnaires.The occupants' comfort temperature was found to be 27.2 °C. Thermal acceptability was very high at 89% even when 26% of the environments were outside the three central categories of the thermal sensation scale. PMV always significantly overestimated the sensation owing to a wide range of adaptations by the subjects. The indoor air speeds were low, indicating a need for ceiling fans. In 50% of the environments the indoor temperature was more than the 28 °C limit. As the buildings were designed for AC mode, running them in NV mode posed challenges. This study calls for elaborate field studies in offices in Japan for the development of custom made adaptive comfort standards.

DECISION MAKING OF OWNERS TO REPAIR AND RENOVATE LEASE OFFICE BUILDINGS

The repair and the renovation of lease office buildings are often changed from the initial master plan because condition of the material and equipment varies along with the environment and the circumstance. When the time to repair or renovate some parts of the building comes, the decision making can be classified into 2 patterns according to the categories of the owners. One is those who intend to hold buildings for long term, another is those who invest to real estate for revenue. The model of the decision making by these 2 kinds of owners is developed based on data of real lease office buildings in Tokyo under a property manager. The model can be also used to forecast owners' decision making of the repair and the renovation of lease office buildings.

CO 2-emissions reduction potential and costs of a decentralized energy system for providing electricity, cooling and heating in an office-building in Tokyo

Decentralized energy systems are thought to have great potential for supplying electricity, cooling, and heating to buildings. A decentralized system combining a solid oxide fuel cell (SOFC) with an absorption chiller-heater (ACH) is proposed. The CO 2-emissions and costs of using different configurations of this SOFC-based system to provide an office building in Tokyo with electricity, cooling and heating are calculated by using an SOFC-model and an absorption-chiller model together with data for cooling and heating loads measured at an office building in downtown Tokyo. The results are compared with the CO 2-emissions and costs of a conventional system that obtains the base electricity requirements as well as electricity for an electric chiller–heater system from the central power grid. The fully decentralized SOFC-based energy system could result in a potential CO 2 reduction of over 30% at an estimated cost increase of about 70% compared to the conventional system.

空調システムにおける微生物汚染の実態と対策に関する研究 : 第1報 微生物の生育環境と汚染実態

For reducing the indoor air pollution in connection with microbes, it is important to clarify quantitatively the actual contamination status of the microbes in an air-conditioning system which greatly affects the indoor air quality. This paper reports the results obtained from the survey about the growth environment and the pollution actual status of microbes in the air-conditioning systems equipped in eight office buildings in Tokyo. The main conclusions obtained from this research are as follows. (1) By measurement of the growth speed of Alternari alternate, Eurotium herbariorum, Aspergillus penicillioides which used as a biosensor in this study, it is shown clearly that the environment down stream of a coil is favorable environment for the microbes of the 70-95% of the minimum relative humidity for growing. (2) On some object surfaces of an air filter, a coil, and a humidifier, when many, 10,000 microbes per square centimeter were measured.

Life‐cycle cost analysis based on a renewal model of earthquake occurrences

AbstractA decision methodology for the management of seismic risk of a single building is presented. The decision criterion aims at minimizing the expected life‐cycle cost, including the initial cost of the design and the expected cost of damage due to future earthquakes. The expected life‐cycle cost of each design alternative is formulated using a renewal model for the occurrence of earthquakes in a seismic source, which accounts for the temporal dependence between the occurrence of ‘characteristic’ earthquakes. The formulation involves the expected damage cost from an earthquake of specified magnitude in a given source. This term is estimated by simulating the processes of fault rupture, elastic wave propagation, surface soil amplification, dynamic structural response and generation of damage costs. As an example, the methodology is applied to an actual office building in Tokyo. A simple decision problem between two design alternatives is set: a bare steel moment frame, and the same frame equipped with oil dampers. Through this case study, the installation of the oil dampers is demonstrated to be effective in reducing the life‐cycle cost of the building under consideration. Copyright © 2004 John Wiley & Sons, Ltd.

Heat discharges from an office building in Tokyo using DOE-2

In this paper, the net heat discharge of an office building is estimated taking into account the various components of heat that flows into the building and out from the building. The results have suggested that the diurnal profiles, especially the peak heat discharge time, are significantly different from that of energy consumption by the building, while most of the past studies on the urban heat environment have assumed the heat discharges to be coincident with the energy consumption. The results also suggested that the choice of an air conditioning type plays an important role in the heat discharges.

423 氷蓄熱個別分散型空調機の省エネルギー性に関する一考察

The energy consumption and resultant CO_2 emission of a commercial ice thermal storage unitary air conditioner are calculated by a simple simulation program which is based on its performance data released by its manufacturer, and hourly averaged cooling load and outdoor temperature data for an average office building in Tokyo. The result shows that the cooling mode of operation utilizing nighttime ice thermal storage is not energy saving in comparison with the conventional cooling mode of operation without thermal storage. This fact is also shown by discussion of energy consumption based on a criterion derived in this study.

東京とヨーロッパ5都市における空調機負荷特性の比較

This paper describes the simulation results of annual air conditioning load in the model office building in Tokyo and five European cities, Rome, Zurich, Paris, Frankfurt and London. The purpose of this study is to describe the characteristic of heating and cooling energy consumption in Japan in comparison with Europe where space heating is considered more important than cooling. From the comparison of annual air conditioning loads in the office building, the total load in Tokyo showed the greatest value which is 1.4 times of the total load in Paris. Since the space cooling load of office buildings is affected by solar radiation through windows and internal heat gains, the annual space cooling load is much greater than the space heating load in all cities. However, for the air conditioning coil loads, the heating load is greater than the cooling load in the most European cities due to cooling effect of outdoor air for ventilation reauirment. From the simulation results, it was confirmed that cooling is primarily important in Tokyo in comparison with the European cities where the heating shared the largest portion even for the office building.

Active mass driver system as the first application of active structural control

AbstractAn active mass driver (AMD) system has been installed in a ten‐storey office building in Tokyo to suppress vibration in both one‐translational and the torsional directions under earthquake and wind loadings. This installation is the first application of active structural control in the civil engineering field. This paper describes the objective building and its dynamic properties, the composition and specification of the AMD system, the control strategy, the control purpose, and the system's effectiveness based on observation records. The control strategy has basically been introduced as an output feedback control law that is simplified from a state feedback control law in the linear quadratic regulator problem. The responses of both the structure and the AMD system have been recorded since 1989. A structure–controller interaction model is identified to simulate the earthquake observation records and to compare them with the analysed uncontrolled responses. An ARX model is fitted to each set of these observation records to evaluate the control effectiveness as equivalent damping ratios in the vibration modes. Both the simulation and the system identification confirm that the AMD system achieves the control purpose under earthquake excitations. The wind observation records also show high control effectiveness. Copyright © 2001 John Wiley & Sons, Ltd.

Control performance of active-passive composite tuned mass damper

This paper reviews an active control algorithm adopted for an active-passive composite tuned mass damper, which is a unique vibration control device equipped into an office building in Tokyo in 1993. The main purpose of this device is to subdue the response motion of tall buildings under random disturbances such as wind pressures and small earthquakes. The main topics in this paper are: (1) the principle of the acceleration feedback algorithm, (2) the expected control performance, (3) the multi-modal control algorithm, (4) the observed performance of the applications using the algorithm.

蓄熱槽を有する建物の地下部躯体の温度分布性状に関する研究 : 第1報 地下部躯体の長期温度実測結果とFEM解析

The double slab space composed of foundation slab and footing beams is often used as a heat storage tank of airconditioning system. The temperature of the tank water is about 45 degree of centigrade in winter and about 5 in summer. This hot and chilled tank water causes thermal stresses in the reinforced concrete basement structure. In order to study on the thermal behavior of structures due to heat storage tank, a long term temperature measurement (about one and a half year) of a office building in Tokyo was carried out. The temperature was measured for the water, foundation slab, exterior and interior footing beams, slab and exterior wall of machine room, and so on. From the measured data, the mean temperature and temperature gradient of cross section of member were derived. Unsteady static heat conduction of the building and surrounding soil was analized by 2-dimensional finite element method. The analidcal results were good agreement with the measured data.