Urban Office Buildings Research Articles

Influence of Transparent Envelope Parameters on Office Building Energy Use Intensity in the Different Thermal Climate Regions of China

The role of the transparent envelope in energy savings is crucial as it accounts for a significant proportion of the total energy loss (between 30 and 40%). This paper focuses on the identification of reasonable parameters for the transparent envelope in different climatic regions. To achieve this goal, typical urban office buildings from four different climatic regions are used as research objects. A total of 1600 scenarios were simulated to investigate the variation of energy use intensity, including transparent envelope parameters, meteorological parameters and different types of glazing. The results show that for south-facing transparent envelope facades, type D glazing is the most energy efficient in severe cold regions, type C in colder regions and type B in the other two climatic regions. No solar shading is required in the very cold region. Horizontal shading can be an effective method for saving energy in colder climates, while comprehensive shading can be beneficial in other regions. Deep shading is particularly energy efficient if it meets lighting requirements. For example, in Guangzhou, energy savings of 13.46%, 15.47%, 7.01% and 7.02% can be achieved in the east, west, south and north directions, respectively, using B-type glazing and a comprehensive shading depth of 900 mm.

Improvement of methods of obtaining urban TMY and application for building energy consumption simulation

In the development process of building energy conservation design, the correct provision of local Typical Meteorological Year (TMY) data is a prerequisite and basic work to evaluate building energy consumption, which directly affects the fine use of outdoor data for building energy conservation. Based on the recorded and observed data of meteorological stations in China, the acquisition and correction methods of TMY were studied by mathematical statistics and target searching, and the building energy consumption simulation of urban office buildings was conducted to verify the accuracy of the method, including:(1) Reviewed the generation method for TMY and the acquisition of data.(2) Based on the existing TMY data, the best spatial interpolation method of adjacent stations is studied by using the standard deviation method, and the selection method of the best number of stations on a large regional scale is given.(3) An improved method of urban environment TMY is proposed. The dry bulb temperature and relative humidity of the building site are corrected to generate TMY under Urban Heat Island (UHI) effect. The research in this paper improves the coverage and accuracy of urban TMY data and supplies basic research support for building energy-saving designs.

Overheating and energy use in urban office buildings in a warming climate

AbstractBuildings are responsible for one‐third of the UK's greenhouse gas (GHG) emissions. The move to reduce emissions has resulted in recent stringent building regulations primarily aimed at reducing heating and associated energy use, often by improving the building fabric's airtightness. However, internal gains dominated, highly–insulated and airtight non‐domestic buildings will likely overheat in the projected warming climate, requiring energy‐intensive cooling, thus diminishing the effectiveness of heating efficiency focused regulations. This research investigated the effects of the warming climate on overheating and energy use and resulting emissions in representative urban office spaces in London in the present‐day and projected future climates using hourly dynamic thermal simulations. Findings suggest that airtight and highly–insulated office buildings in the temperate UK will overheat in the 2050s. Heating demand reduces by at least 36% in the 2050s but electricity consumption and summertime space conditioning will increase by at least 13% and 55% respectively when hybrid cooling is adopted to ameliorate overheating. Despite the increase, a mixed‐mode ventilation strategy is one of the ways of achieving overall energy efficiency while meeting benchmark overheating and emissions targets. Current heating‐focused legislation needs to be re‐evaluated to account for the effects of the warming climate and overheating risks.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India.

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

Perancangan dan Analisa Kinerja Fiber to the Building (FTTB) untuk Mendukung Smart Building di Daerah Urban

The development of digital technology makes it easy for humans to do activities, including compliance with the requirement of voice, data, and video communication in office buildings. Infrastructures are a primary consideration for a reliable connection, large-capacity, and stable communication lines. Recently, Fiber-optic communication systems are now the backbone of information signal delivery technology. This paper proposes a design of optical fiber transmission media for deployment in urban office buildings. It has been called fiber to the building (FTTB), which uses a fiber optic communication system to support the availability of multimedia network in an office area. A typical office building in an urban area has a multilevel structure that is used by various companies with multimedia network access services to support business activities. This study considers XGPON technology as a fiber optic-based broadband access technology that is deemed appropriate to the needs of the use of a multimedia network. The design begins with conducting a data collection survey. The next is the chosen device components based on the estimated distribution of the number of users. There are three parameters will be calculated include Power Link Budget (PLB), Rise Time Budget (RTB), and Bit Error Rate (BER), to determine the design feasibility. Based on PLB, RTB, and BER data, the proposed fiber to the building (FTTB) can meet the parameters to be achieved in the design, namely PLB of -27,24 dBm for downstream and -11,68 dBm for upstream, the value of is 0,049 ns, and value of BER is 0,186 x 10-1085. The design of FTTB can meet the requirement of users with a bandwidth of 9014,4 Mbps for 1200 users.

Removal of formaldehyde in urban office building by the integration of ventilation and photocatalyst-coated window

Indoor formaldehyde (HCHO) has become a big problem for the development of health building in cities. Ventilation and photocatalysis are two efficient tools to remove HCHO. The comparison and integration of the two methods was conducted. Pure titanium dioxide (TiO2) and Fe/N-TiO2 were prepared and coated to a glass plate, and experimental and computational fluid dynamics (CFD) method was used to analyze photocatalysis of HCHO. The reaction kinetic of HCHO degradation was studied by experiment, and the efficiency of Fe/N co-doped TiO2 exhibited 2.3 times than that of pure TiO2. Then the CFD method was used to study the removal of HCHO by ventilation and photocatalysis in an office. The evaluations were conducted with continuous and transient released HCHO, separately. In the case of continuous release, the average concentration of HCHO was reduced by 27 % with the contribution of photocatalyst. In the case of transient release, the removal efficiency was improved by 21 % when the photocatalyst was added. This research shows that the CFD method is a convenient tool to explore the effect of novel materials in indoor environment.

TOWARDS A BETTER PERFORMANCE IN OFFICE BUILDINGS BY INTEGRATING NATURAL ELEMENTS

The fast rhythm of today’s economic environment imposes the full potential of the workforce and no longer affords to waste any. There are many factors in the workplace environment that influence the performance of the occupants. Workplace design plays a major part as one of these factors. Meanwhile, recent studies have shown a positive correlation between nature, the built environment and human performance. On average, people spend ninety percent of their time in artificial built environments and man-made environments that weaken the opportunity for humans to connect with their natural environment. The outcome of this study is intended to provide insight into the perception of natural elements design in the context of urban office buildings' environment and a greater understanding of how integrating these elements into workplace environments could renew a historically innate human connectedness to the natural environment that support occupants' productivity, and therefore their overall health and well-being.

Measuring Emotional Response to a Planting Activity for Staff at an Urban Office Setting: A Pilot Study

Background: Interaction with occupation-centered activities, such as gardening, is associated with improved mental health. With limited evidence supporting the effects of short-term nature-based interventions on employees’ emotional states, the purpose of this research was to understand the impact of a one-time, short-term nature-based intervention on the emotional state of employees at an urban office building.

Heat Stress Pattern in Conditioned Office Buildings with Shallow Plan Forms in Metropolitan Colombo

This paper critically evaluates indoor overheating of multilevel office buildings in Colombo—a tropical warm humid city. The work questions the building morphological characteristics on thermal performance and indoor climate, thus the levels of Building Energy Indices (BEI) of air conditioned buildings. Pattern of heat stress on buildings due to building characteristics and its relationship to the BEI were identified. A study of 87 multilevel office buildings contributed to identify two critical cases in shallow plan form with similar morphological characteristics such as wall-to-window ratio, aspect ratio, orientation, occupant and equipment density, and façade architecture. A comprehensive thermal performance investigation on these two critical cases quantified the heat stress patterns on their facades and thus indoor thermal environments. Indoor air temperature during office hours in 3 m × 3 m multizones across the depths and lengths in these two buildings showed deviations up to 10.5 °C above the set point temperature level (24 °C). Findings highlight the severity of heat stress on air conditioned indoor environments and the need to address this issue for energy sustainability of urban office buildings in the tropics.

Modeling energy-related CO2 emissions from office buildings using general regression neural network

Carbon dioxide (CO2) emissions from urban office buildings energy usages (BEC) constitute a substantial component of anthropogenic greenhouse gas emission, and are set to rapidly increase with further urbanization. Establishing a concise, accurate, and realistic model that can predict future emissions is challenging but essential for strategies to develop low carbon construction and sustainable development in urban areas. In this paper, the operational energy use for 294 office buildings across China was collected and analyzed. We focus on four main variables, and analyze a further ten second-level variables, to elucidate the role that a building’s occupants, its structural characteristics, and localized natural conditions play in determining energy consumption. Using general regression neural network (GRNN), the factors’ direct and indirect effects on energy consumption were tested. A building’s structural attributes had the most impact on energy-related CO2 emissions, followed by the relevant socioeconomic conditions, the micro-climate, and finally the regional climate. A version of the model that was constructed with interaction between the four main variables was found to be the most precise. GRNN combined with urban development scenarios was used for the prediction of cities’ future CO2 emissions. Economic development and improving standards in the construction industry could have significant impacts on future CO2 emissions. This study provides a detailed method that could be used to explore the dynamics of office energy use and competing options for the construction of low-carbon office buildings.

Influence of climate change on summer cooling costs and heat stress in urban office buildings

Indoor climatic conditions are strongly influenced by outdoor meteorological conditions. It is thus expected that the combined effect of climate change and the urban heat island effect negatively influences working conditions in urban office buildings. Since office buildings are particularly vulnerable to overheating because of the profound internal heat gains, this is all the more relevant. The overheating in office buildings leads to elevated cooling costs or, because additional work breaks are required by legislation in some countries, productivity losses. We have developed a methodology incorporating urban climate modelling and building energy simulations to assess cooling costs and lost working hours in office buildings, both for current-day and future climate, extending towards the end of the twenty-first century. The methodology is tailored to additionally assess the impact and benefits of adaptation measures, and it is designed to be transferable from one city to another. Results for a prototype building located in three different European cities (Antwerp, Bilbao and London) illustrate the challenge in keeping Western-European office buildings comfortable until the end of the twenty-first century without adaptation measures, and the beneficial effect of adequate adjustments. The results further illustrate the large decreases in cooling costs (up to 30%) caused by the introduction of (external) shading and increased night-time ventilation in actively cooled buildings, and the improvements in working conditions in free-running buildings caused by moving workers to cooler locations and splitting workdays in morning and evening shifts.

Energy, environmental and economic assessment of electricity savings from the operation of green roofs in urban office buildings of a warm Mediterranean region

Green roofs are an important technique to efficiently mitigate adverse environmental impacts of buildings. This study focuses both on energy conservation and sustainability related aspects of two alternative green roof solutions applied to a typical urban office building in representative climatic areas of Cyprus in the Eastern Mediterranean. Simulations regarding the buildings’ energy demand were conducted using EnergyPlus software. Based on these results and using an in-house developed algorithm, the primary energy consumption for each alternative solution was computed, assuming variable refrigerant flow air-to-brine heat pump as heating and cooling system, coupled with a calculation of the associated emissions of carbon dioxide, nitrogen oxides and sulphur dioxide. The analysis shows a reduction in primary energy consumption up to 25% in heating and up to 20% in cooling operation, thanks to the use of green roofs, and a corresponding reduction in emissions. The economic viability of the proposed green roof solutions was also examined, taking into consideration both monetary and environmental costs. The results show that the green roof solutions increase the lifetime cost up to 40,000 €, however they can lead to additional environmental and economic benefits which are hard to quantify.

Lighting energy consumption in ultra-low energy buildings: Using a simulation and measurement methodology to model occupant behavior and lighting controls

As building owners, designers, and operators aim to achieve significant reductions in overall energy consumption, understanding and evaluating the probable impacts of occupant behavior becomes a critical component of a holistic energy conservation strategy. This becomes significantly more pronounced in ultra-efficient buildings, where system loads such as heating, cooling, lighting, and ventilation are reduced or eliminated through high-performance building design and where occupant behavior-driven impacts reflect a large portion of end-use energy. Further, variation in behavior patterns can substantially impact the persistence of any performance gains. This paper describes a methodology of building occupant behavior modeling using simulation methods developed by the Building Energy Research Center (BERC) at Tsinghua University using measured energy consumption data collected by the University of Washington Integrated Design Lab (UW IDL). The Bullitt Center, a six-story 4831 m2 (52,000 ft2) net-positive-energy urban office building in Seattle, WA, USA, is one of the most energy-efficient buildings in the world (2013 WAN Sustainable Building of the Year Winner). Its measured energy consumption in 2015 was approximately 34.8 kWh/(m2∙yr) (11 kBtu/(ft2∙yr)). Occupant behavior exerts an out-sized influence on the energy performance of the building. Nearly 33% of the end-use energy consumption at the Bullitt Center consists of unregulated miscellaneous electrical loads (plug-loads), which are directly attributable to occupant behavior and equipment procurement choices. Approximately 16% of end-use energy is attributable to electric lighting which is also largely determined by occupant behavior. Key to the building’s energy efficiency is employment of lighting controls and daylighting strategies to minimize the lighting load. This paper uses measured energy use in a 330 m2 (3550 ft2) open office space in this building to inform occupant profiles that are then modified to create four scenarios to model the impact of behavior on lighting use. By using measured energy consumption and an energy model to simulate the energy performance of this space, this paper evaluates the potential energy savings based on different occupant behavior. This paper describes occupant behavior simulation methods and evaluates them using a robust dataset of 15 minute interval sub-metered energy consumption data. Lighting control strategies are compared via simulation results, in order to achieve the best match between occupant schedules, controls, and energy savings. Using these findings, we propose a simulation methodology that incorporates measured energy use data to generate occupant schedules and control schemes with the ultimate aim of using simulation results to evaluate energy saving measures that target occupant behavior.

Redeveloping Newcastle: Public Incentives to Spur Commercial Development

Louise Dejan was a successful real estate developer operating throughout northeast England. The city council of her hometown of Newcastle faced a problem common to many areas: how to encourage private investment into less attractive areas. In August 2012, Newcastle's East Pilgrim Street neighborhood remained an eyesore, despite its great location between the city's Central Station and city hall. It was a natural place for Dejan to build a typical urban office building over street-level retail building. On a particularly attractive site sat an asbestos-contaminated building, which was a former home to the Bank of England. The costs of remediation had kept developers like Dejan away for many years. To encourage redevelopment, the Newcastle City Council had recently designated the East Pilgrim Street neighborhood an Accelerated Development Zone (ADZ). This gave Dejan access to Tax Increment Financing (TIF), a method by which public funds could be spent to encourage private sector redevelopment of designated parcels of land. After studying the details of TIF and the financial projections of a potential new development, Dejan had to decide whether she should be the first to redevelop property in this well-located but seemingly forgotten neighborhood.

Indoor air quality in urban office buildings

Several epidemiological studies have shown a relation between exposure to air pollutants and human adverse health effects. Consequently, the quality of air inside homes, offices, schools and other private and public buildings is an essential determinant for health and well-being, considering that people spend the majority of their time indoors. Over the last 30 years, numerous studies indicated that there are some common health symptoms associated with office workers, which are less apparent when they leave the building. The present study was conducted in order to evaluate the indoor air quality (IAQ) in office buildings. The indoor pollutants carbon dioxide (CO2), carbon monoxide (CO), particulate matter with an aerodynamic diameter < 10 µm (PM10), volatile organic compounds (VOCs), formaldehyde (H2CO), ozone (O3), fungi and bacteria were assessed in seven offices located in an urban environment, as well as temperature, relative humidity and air velocity. Results showed that all the measured pollutants, with the exception of CO, exceeded the guidelines.

Indoor air quality in urban office buildings

Several epidemiological studies have shown a relation between exposure to air pollutants and human adverse health effects. Consequently, the quality of air inside homes, offices, schools and other private and public buildings is an essential determinant for health and well-being, considering that people spend the majority of their time indoors. Over the last 30 years, numerous studies indicated that there are some common health symptoms associated with office workers, which are less apparent when they leave the building. The present study was conducted in order to evaluate the indoor air quality (IAQ) in office buildings. The indoor pollutants carbon dioxide (CO2), carbon monoxide (CO), particulate matter with an aerodynamic diameter < 10 µm (PM10), volatile organic compounds (VOCs), formaldehyde (H2CO), ozone (O3), fungi and bacteria were assessed in seven offices located in an urban environment, as well as temperature, relative humidity and air velocity. Results showed that all the measured pollutants, with the exception of CO, exceeded the guidelines.

Statistical Analyses of Energy Consumption Data in Urban Office Buildings of Changsha, China

The purpose of this study is to analyze the actuality of urban office buildings energy consumption in Changsha, China. 45 urban office buildings were selected and the investigations on these buildings energy consumption in 2007, were carried through. Survey data of the investigated buildings were analyzed by SPSS. The results showed that the growth of building power intensity (BPI) and building energy intensity (BEI) in office buildings of Changsha showed a normal distribution with increased gross floor area (GFA); the mean of the BEI in government office buildings is 72.30 kWh/(m2·a), with about 75% electricity; the mean of the BEI in commercial office buildings is 71.14 kWh/(m2·a), with about 93% electricity. The energy structures of these buildings need further optimization. These general conclusions provide some information for fundamental work such as investigations into the energy consumption data and formulation of the renovation plans.

Co-optimisation of indoor environmental quality and energy consumption within urban office buildings

This study aimed to develop a multi-component model that can be used to maximise indoor environmental quality inside mechanically ventilated office buildings, while minimising energy usage. The integrated model, which was developed and validated from fieldwork data, was employed to assess the potential improvement of indoor air quality and energy saving under different ventilation conditions in typical air-conditioned office buildings in the subtropical city of Brisbane, Australia. When operating the ventilation system under predicted optimal conditions of indoor environmental quality and energy conservation and using outdoor air filtration, average indoor particle number (PN) concentration decreased by as much as 77%, while indoor CO2 concentration and energy consumption were not significantly different compared to the normal summer time operating conditions. Benefits of operating the system with this algorithm were most pronounced during the Brisbane's mild winter. In terms of indoor air quality, average indoor PN and CO2 concentrations decreased by 48% and 24%, respectively, while potential energy savings due to free cooling went as high as 108% of the normal winter time operating conditions. The application of such a model to the operation of ventilation systems can help to significantly improve indoor air quality and energy conservation in air-conditioned office buildings.

Influence of ventilation and filtration on indoor particle concentrations in urban office buildings

This study aimed to quantify the efficiency of deep bag and electrostatic filters, and assess the influence of ventilation systems using these filters on indoor fine (<2.5 μm) and ultrafine particle concentrations in commercial office buildings. Measurements and modelling were conducted for different indoor and outdoor particle source scenarios at three office buildings in Brisbane, Australia. Overall, the in-situ efficiency, measured for particles in size ranges 6–3000 nm, of the deep bag filters ranged from 26.3 to 46.9% for the three buildings, while the in-situ efficiency of the electrostatic filter in one building was 60.2%. The highest PN and PM2.5 concentrations in one of the office buildings (up to 131% and 31% higher than the other two buildings, respectively) were due to the proximity of the building's HVAC air intakes to a nearby bus-only roadway, as well as its higher outdoor ventilation rate. The lowest PN and PM2.5 concentrations (up to 57% and 24% lower than the other two buildings, respectively) were measured in a building that utilised both outdoor and mixing air filters in its HVAC system. Indoor PN concentrations were strongly influenced by outdoor levels and were significantly higher during rush-hours (up to 41%) and nucleation events (up to 57%), compared to working-hours, for all three buildings. This is the first time that the influence of new particle formation on indoor particle concentrations has been identified and quantified. A dynamic model for indoor PN concentration, which performed adequately in this study also revealed that using mixing/outdoor air filters can significantly reduce indoor particle concentration in buildings where indoor air was strongly influenced by outdoor particle levels. This work provides a scientific basis for the selection and location of appropriate filters and outdoor air intakes, during the design of new, or upgrade of existing, building HVAC systems. The results also serve to provide a better understanding of indoor particle dynamics and behaviours under different ventilation and particle source scenarios, and highlight effective methods to reduce exposure to particles in commercial office buildings.

Vertical particle concentration profiles around urban office buildings

Abstract. Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such, this study aimed to assess the influence of vehicle emissions and nucleation formation on particle characteristics (particle number size distribution – PNSD and PM2.5 concentration) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PNSD, particle number (PN) and PM2.5 concentrations, respectively, for up to three weeks at each building. The results showed that both PNSD and PM2.5 concentration around building envelopes were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During nucleation events, PN concentration in size range of &lt;30 nm and total PN concentration increased (7–65% and 5–46%, respectively), while PM2.5 concentration decreased (36–52%) with height. This study has shown an under acknowledged role for nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for studies of both human exposure and particle dynamics.