Commercial Office Buildings Research Articles

The need for economic performance measures for life cycle costing of sustainable commercial office buildings

PurposeThe purpose of this paper is to investigate the current level of awareness, usage and advocated benefits of economic performance measures of life cycle costing (LCC) in sustainable commercial office buildings.Design/methodology/approachQuestionnaire survey to 120 construction professionals was used to gauge the current level of awareness, usage and advocated benefits of economic performance measures in LCC.FindingsThe key findings of the statistical analysis indicated that there is a low awareness and usage of economic performance measures, and revealing the entire value of capital outflow alternatives was the most advocated benefit of its application.Research limitations/implicationsAlthough the data used in this paper were from professionally qualified members of either the Royal Institution of Chartered Surveyors (RICS), the Chartered Institute of Building (CIOB) and the British Institute for Facilities Management (BIFM), the research is limited in some ways in that it does not cover all the professionals in the construction industry. Nevertheless, all the professionals who responded to the questionnaire have up-to-date level of awareness of economic performance measures in LCC.Practical implicationsThe use of economic performance measures helps to make available the information required for building performance. Therefore, economic performance methods in LCC are useful devices for users to appraise and distribute recognisable values from initial costs, operating and maintenance costs to clients in the life cycle of an asset.Social implicationsValue for money for construction products and its facilities should not be viewed only in terms of costs to design and construction. Rather, it is vital for corporate occupants and society in general to consider other key variables such as operations, maintenance, renovation, replacement and end-of-life costs.Originality/valueThis study fills the gap in the existing knowledge by addressing concerns over performance measurement to improve the confidence in LCC for sustainable commercial office buildings.

Simulation of a biomimetic façade using TRNSYS

Biomimicry – innovation inspired by nature – is a creative methodology that translates characteristics from the biological world to the domain of human technology. Functional biomimicry offers opportunities to advance the development of flexible building facades. Following biomimetic principles, external fur and bioheat transfer (blood perfusion) and were combined into a mathematical model of a commercial office building façade for a west-facing wall of an office building situated in Melbourne, Australia. TRaNsient SYstem Simulation (TRNSYS) software tool was used to determine temperatures and heat transfer of this biomimetic façade in summer design conditions compared to a reference. The biomimetic façade was simulated to provide cooling of greater than 50Wm−2 and reduced mean surface temperatures in the occupied zone by 2.8°C, compared with the reference.

Development of Whole‐Building Energy Models for Detailed Energy Insights of a Large Office Building with Green Certification Rating in Singapore

AbstractDetailed insights on energy use are missing for the building stock in Singapore that may aid reduction of energy consumption through a targeted approach. Therefore, we created two whole‐building energy models for a large commercial office building in the tropics representing a fully glazed and a concrete façade. We used Singapore's current building codes, which include compliance with local green‐rating system, and collaboration between two entities with first‐hand experience with design, construction, and operation of buildings in the tropics to define the models. The models provide a first step towards a set of standardized inputs and assumptions for office buildings in the tropics. The results show an energy use intensity of 146 kWh m−2 a−1. The three highest energy consumers are air conditioning and mechanical ventilation (43 %), lighting (29 %), and plug loads (21 %) whereas the two main sources of cooling loads are ventilation (29 %) and conduction and radiation through windows (20 %). Finally, we evaluated the effects of exterior shading on the fully glazed energy model to demonstrate the use of the models to building stakeholders.

Optimum Facade Design for Minimization of Heating and Cooling Demand in Commercial Office Buildings in Australian Cities

Optimum Facade Design for Minimization of Heating and Cooling Demand in Commercial Office Buildings in Australian Cities

Control strategies for dynamic insulation materials applied to commercial buildings

This paper evaluates the potential heating and cooling energy use and cost savings associated with improved controls of dynamic insulation materials (DIMs) when used in multilayered wall assemblies for commercial office buildings. Using a genetic algorithm (GA) based optimization technique, optimum R-value settings are identified for the DIMs throughout the year. These optimal R-value settings are selected to maximize energy cost savings when compared to traditional static insulated wall systems. It is found that optimal control settings for DIMs depend on several factors including building design and operation strategies as well as climatic conditions. Moreover, the optimal settings were found to depend on the orientation of exterior walls and well as the climatic conditions. Specifically, the analysis results indicate that north-facing walls are more active and frequently have to change their R-value in order to minimize the office building energy use and cost. When optimally controlled, DIMs could save up to 17% of annual heating and cooling energy costs for US office buildings.

Impact of structural design solutions on the energy and thermal performance of an Australian office building

Concrete is a heavyweight construction material whose high thermal mass could increase the thermal storage capacity of a building envelope and in turn affect indoor thermal comfort. Selecting an appropriate method for concrete construction and form could also affect the total energy performance and thermal comfort of a building, a fact that is often overlooked by structural engineers. This study presents the results of energy simulations of the potential impact that concrete construction forms, in particular two slab types, and structural materials have on the energy consumption of archetypal commercial office buildings in five major Australia cities (Sydney, Melbourne, Canberra, Brisbane and Darwin). This study has three stages: 1) a structural analysis of two slab types (Flat and Waffle slab); 2) the selection of two types of structural concrete (conventional Normal weight concrete and novel Ultra-lightweight concrete); 3) a comparative analysis to quantify the magnitude of the change in predicted annual energy consumption due to changes in the form of construction and the type of structural concrete. The energy simulation results showed that the thermal energy performance of the building was influenced by structural materials and slab types. It is shown that the thermal capacity of the concrete construction forms can be utilized to shift thermal loads, reduce peak demand and reduce operational energy consumption. The selection of an appropriate concrete type was more important in terms of energy performance in the coldest (Melbourne and Canberra) and hottest (Darwin) climate zones of this study.

DESIGN AND IMPLEMENTATION OF CONSTRUCTION MATERIAL MANAGEMENT SCHEME BASED ON RFID TECHNOLOGY

With the improvement of construction demand and the reduction of land price, the construction of all kinds of buildings has become the current development trend in addition to the need for housing. Whether it is a large commercial center, office or landmark building, its construction materials in addition to enhancing the performance, but also to build an automated and effective material management system. This paper studies the design and implementation of the construction material management scheme based on RFID technology, hoping to improve the management system and improve the management efficiency through the application of RFID technology.

Income risk in energy efficient office buildings

This article examines the impact of improving energy efficiency of office buildings on their financial risk. While multiple studies report a sustainability premium little is known about the corresponding risk. This research reviews the financial benefits in the context of their impact on risk. After a theoretical analysis of the topic, it forms two hypotheses which are supported with empirical tests performed on a large panel dataset of US commercial office buildings. Changes in the magnitude of the green premium in rent and changes in rental volatility are used as indicators of financial risk associated with energy certification. The study concludes that acquiring an EnergyStar certificate is related to a structural change in statistical characteristics of rents which may be related to the level of energy efficiency. The average effect is positive but varies over time.

Influencing factors and energy-saving control strategies for indoor fine particles in commercial office buildings in six Chinese cities

Experimental studies on indoor fine particles were performed in actual commercial offices in six Chinese cities: Beijing, Shanghai, Guangzhou, Tianjin, Shijiazhuang and Chengdu. Particle introduced through outdoor air supply (OA) system was the most significant contributor to indoor PM2.5. In most cases, the OA systems of the six office buildings could not provide enough protection for staff. The first reason was the insufficient filtration efficiency of the OA system for PM2.5 due to filter bypass and design shortage. The tested filtration efficiency of the OA system for PM2.5 ranged from 17.0±0.9% to 55.7±2.8%. The gaps between the tested and rated filtration efficiencies ranged from 4.4% to 26.3%. The gaps between the rated and required filtration efficiencies ranged from 7.4% to 64.5%. The second reason was the superfluous outdoor air supply rate. The outdoor air supply rates per staff could reach 7.5L/s to 12.8L/s with the operating OA systems, much higher than the ASHRAE guideline. Five control strategies (including higher level filters, minimum outdoor air supply rates, portable air cleaners and combinations of these options) were proposed for HVAC system to reduce indoor PM2.5 concentration level to 35μg/m3. The reduced indoor PM2.5 exposure per power under strategy 2 (minimum outdoor air supply rate+higher level filters) was the highest in all cases. The total energy consumption of HVAC systems under strategy 2 was only 42%-71% of the current energy consumption.

Assessment and modelling of the viability of a solar heating system for aquatic centres in southern Australia

Aquatic centres are large users of energy for water and space heating with an energy intensity which can be up to seven times that of a commercial office building in Australia. Much of the energy is used to heat water to relatively low temperatures, and therefore, solar energy technology is capable of providing this energy. In the residential sector, solar thermal systems for heating water and swimming pools are well-established. This is not the case for commercial swimming pools i.e. aquatic centres. In Australia, a program to encourage commercial pool operators to install solar systems was funded in the early 1980s. This paper has investigated the current use of and attitudes to solar systems in commercial pools through a survey of municipal pool operators in Victoria, southern Australia. The survey found that there has been very little increase in the use of solar energy and that perceived barriers to the use of the technology remain the same as they were nearly 30 years ago. Lack of roof area, poor payback periods and an inability of solar to meet pool heating needs are the most common misconceptions. The paper investigates these misconceptions by analysing the hot water needs of a large aquatic centre in Melbourne. It was found that there was sufficient roof area to accommodate a solar system that would provide a solar fraction of 0.60 and the simple payback period for a solar system using unglazed solar collectors was approximately 6.7 years at current gas prices. These are predicted to rise significantly making solar energy an even more attractive proposition for commercial pool heating. Failure of past incentives to stimulate the uptake of solar pool heating systems necessitates a revised approach. Key stakeholders (industry bodies, local governments, pool operators, manufacturers, relevant HVAC consultants and research organisations) all need to be involved in an exemplar project to demonstrate the technology’s viability for aquatic centres.

Income Risk in Energy Efficient Office Buildings.

The study investigates uncertainty of financial performance of energy efficient office buildings to establish how making an asset energy efficient changes its financial characteristics. Two hypotheses explaining why a change may occur are presented and examined (one based on higher demand and one on higher economic efficiency). A large panel dataset, consisting of 30 time periods for 14,395 US commercial office buildings, is examined using different econometric approaches. Overall, the results seem to support theoretical predictions and show a structural change in income risk characteristics of energy efficient assets.

A study on energy performance of 30 commercial office buildings in Hong Kong

A study of energy performance of 30 existing commercial office buildings in Hong Kong has been carried out. Energy audits have been conducted and the data obtained from utility bills, design documents and on-site measurements have been thoroughly assessed. Energy Utilization Index (EUI) as well as carbon emission of each building have been calculated to compare with previous studies and other benchmarks. EUI study in terms of over-time evolution and by categories have been also undertaken. An energy breakdown of 30 buildings by end-user systems was derived, showing that 68% of energy on average was consumed by HVAC system, while lighting accounted for 14% and the other systems shared the else 18% of consumption. Compared with other countries, HVAC system in Hong Kong consumed the highest proportion of energy among all end-user systems. Moreover, the COP of HVAC systems have been analyzed, indicating that with an average deviation of 16% between the design and measured chiller COP for all studied buildings, the measured chiller COP can barely meet the standard issued by the government. A district cooling system for a group of office buildings has been investigated as well, demonstrating better chiller and system efficiencies but resulting in the over-capacity installation of cooling units. To further predict building energy consumption, a mathematical model based on the measured data has been built through the multiple regression analysis and verified by the back-propagation neural network algorithm. This research is expected to provide theoretical guidance and practical data reference for the relevant evaluations of building energy efficiency.

Understanding the deterministic and probabilistic business cases for occupant based plug load management strategies in commercial office buildings

Plug load monitoring and associated occupant behavior interventions can play a critical role in reducing commercial building energy consumption. This study investigates whether the reduction in building energy consumption justify the added cost of plug load monitoring and occupant energy saving interventions. The objective of this study is to conduct deterministic and probabilistic return-on-investment (ROI) analysis of instrumenting workspaces, monitoring plug load usage, and applying interventions to promote building energy reduction. The study uses the findings of actual occupant energy saving intervention investigations conducted with city and federal government offices in which the association between occupant energy savings interventions and energy use risk was evaluated. While the deterministic approach led to a positive net present value, the interventions failed to recapture the initial investment, and operational expenses given the uncertainties in the estimate of costs and energy use. The mean ten-year net present value was −$3914 at a 6% discount rate considering all U.S. states. From the project manager’s perspective, other non-energy benefits can justify the additional resources.

Understanding the potential of facilities managers to be advocates for energy efficiency retrofits in mid-tier commercial office buildings

Realising energy efficiency opportunities in new commercial office buildings is an easier task than retrofitting older, mid-tier building stock. As a result, a number of government programs aim to support retrofits by offering grants, upgrades, and energy audits to facilitate energy efficiency opportunities. This study reports on a state government program in Victoria, Australia, where the uptake of such offerings was lower than expected, prompting the program team to consider whether targeting facilities managers (FMs), rather than building owners, might be a better way of delivering the program. The influences and practices of FMs that impact on their ability to be advocates for energy efficiency were explored. The results revealed that complex building ownership arrangements, poor communication skills, isolation from key decision making processes, a lack of credible business cases and information, split incentives, and the prospect of business disruptions can all impact on FMs’ ability to drive organizational change. Future program efforts should continue to interrogate the social context of retrofits in mid-tier buildings, including other influences and influencers beyond FMs, and adapt accordingly.

Concepts and philosophy of risk management in real estate industry

This paper presents concepts and philosophy of risk management in the context of real estate development industry. The paper includes an in-depth review of literature for defining real estate development and risk within the existing knowledge pool. The population of this study comprises real estate developments across India and covers three qualitative case examples relating to a single residential family house, commercial three-story office building, and apartment building for identifying elements of work breakdown structure (WBS). Further, these WBS elements are considered grouped into four phases of real estate project management to strategise risk management. The conceptual framework on precepts of risk management has been used for mapping some propositions relating to the real estate development. This paper implies a need for an efficient system of risk management in the real estate practices. This paper contributes to the theoretical foundation for identifying, assessing and analysing risks in the real estate development industry.

IMPACT OF RETROFITTING ENERGY-EFFICIENT DESIGN STRATEGIES ON ENERGY USE OF EXISTING COMMERCIAL BUILDINGS: COMPARATIVE STUDY OF LOW-IMPACT AND DEEP RETROFIT STRATEGIES

This article discusses energy-efficient retrofitting design strategies for commercial office buildings, and examines their effect on energy consumption. The objective of the research was to study how to integrate passive design strategies and energy-efficient building systems to improve building performance, and reduce the energy consumption of existing buildings in three different climate types (cold, mixed and hot climates). First, properties of existing buildings were analyzed based on national CBECS database to determine typical characteristics of office buildings located in Chicago, Baltimore and Phoenix, including size, building envelope treatment and building systems. Then, fourteen different prototypes were developed, varying the building shape and orientation to represent different building stock, and energy modeling was conducted to establish energy usage baseline. Multiple design considerations were investigated based on extensive energy simulations and modeling, where low-impact and deep retrofits were considered. Low-impact strategies included improvements to the building envelope, lighting systems and optimization of HVAC systems operation (without upgrading heating and cooling equipment). Deep energy retrofits also included improvements to building envelope and lighting, and considered changes and improvements to HVAC systems (specifically, integration of radiant systems). Energy modeling was conducted for all prototypes, and results were obtained for the baseline (current energy usage), and energy usage considering low-impact design strategies and deep retrofits. A total of 126 energy models was developed, simulated and analyzed, providing a dataset that captured energy usage for investigated scenarios. The comparative analysis of simulation results was used to determine how specific techniques lead to energy savings in different climate types, as well as for buildings of various shapes and orientations.

The impact of the ambient environment and building configuration on occupant productivity in open-plan commercial offices

Purpose This paper sets out to understand the impact of the ambient environment on perceived comfort, health, wellbeing and by extension productivity in the workplace. Design/methodology/approach The research combined an occupant survey considering satisfaction with the ambient environment, health and wellbeing and workplace behaviour with the monitoring of ambient environmental conditions. Findings The paper demonstrates that the ambient environment can have a significant impact on occupant comfort, health and wellbeing, which in turn has implications for built asset performance. Within the ambient environmental factors considered, a hierarchy may exist with noise being of particular importance. Occupant behaviour within the workplace was also found to be influential. Research limitations/implications The research was limited to a single commercial office building, and a wider range of case studies would therefore be of benefit. The research was also limited to the summer months. Practical implications The findings show that an active approach to asset management is required, by continuously monitoring internal environment and engaging with occupants. This must carefully consider how ambient environmental factors and workplace behaviour impact upon occupants’ comfort, health and wellbeing to ensure the performance of the built asset is maximised. Originality/value This paper demonstrates that both occupiers’ workplace behaviour and ambient environmental conditions can have an impact on occupant comfort, health, wellbeing and productivity. The paper strengthens the case for the active management of the workplace environment through environmental monitoring and behaviour change campaigns supported by corresponding changes to workplace culture.

Climate co-benefits of green building standards: water, waste and transportation

ABSTRACTThis paper quantifies the greenhouse gas (GHG) emissions co-benefits associated with water, waste and transportation usage in certified green commercial office buildings in California. The study compares the measured values of water, waste and transportation usage self-reported by office buildings certified under the Leadership in Energy and Environmental Design rating system for Existing Building Operations and Maintenance (LEED EBOM) to baseline values of conventional California office buildings. The green buildings in the LEED EBOM dataset produced 50% less GHGs due to water consumption than baseline buildings, 48% less due to solid waste management, and 5% less due to transportation. If applied to the entire California office building stock, performance typical of the certified green buildings would save 730,038 MgCO2e/yr (metric tonnes) from transportation, 87,601 MgCO2e/yr from water, and 45,280 MgCO2e/yr from waste, for a total potential savings of about 862,920 MgCO2e/yr relative to conventional construction. In addition, buildings earning additional credits for specified performance thresholds for water and waste in the LEED EBOM code attained performance levels even higher than required by the code provisions, suggesting that such code provisions in other contexts may help incentivize larger GHG emissions reductions than anticipated. Specific recommendations are made for building standards and certification schemes.

Modeling the energy retrofit decision in commercial office buildings

Retrofitting existing buildings has emerged as a primary strategy for reducing energy use and carbon emissions, both nationally and in cities. Despite the increasing awareness of retrofitting opportunities and a growing portfolio of successful case studies, little is known about the decision-making processes of building owners and asset managers with respect to energy efficiency investments. Specifically, the research presented here examines the effects of ownership type, tenant demand, and real estate market location on building energy retrofit decisions in the commercial office sector. This paper uses an original, detailed survey of asset managers of 763 office buildings in nineteen cities sampled from the CBRE, Inc. portfolio. Controlling for various building characteristics, the results demonstrate that ownership type and local market do, in fact, influence the retrofit decision. Overall, this analysis provides new evidence for the importance of understanding ownership type and the varying motivations of differing types of owners in building energy efficiency investment decisions. The findings of both the survey analysis and the predictive model demonstrate additional support for the targeting of energy efficiency incentives and outreach based on ownership entity, local market conditions, and specific physical building characteristics.

Diagnosing thermal behaviour of the administration block of the University of Colombo for retrofitting passive design strategies

Existing non-domestic buildings in developing countries account for a substantial percentage of energy usage for indoor climate control and therefore contribute to carbon dioxide emissions. High levels of air temperatures associated with radiation in warm-humid climates contribute to heat gain and thus indoor overheating conditions and indoor thermal discomfort. These trends have contributed to introducing active systems in building operation resulting in increase of energy consumption. The method used in the study involved on site investigations of thermal behavior of commercial office buildings in urban warm humid climates in Sri Lanka. Literature showing that thermal behavior of building microclimates, form and envelope are important design variables which can act as modifiers of outdoor climate into favorable indoor climates in buildings. The study evaluates the potential of these variables in maintaining indoor thermal comfort. Based on the thermal analysis of the building and immediate surroundings a retrofitting proposal was developed to improve building thermal performance.