Quantifying the ‘human factor’ in office building energy efficiency: a mixed-method approach

Effect of facade components on energy efficiency in office buildings

High energy consumption is a global issue nowadays. The building sector consumes a tremendous amount of energy. Inspiration from nature (biomimicry) could be the driving force in architecture to achieve a high level of sustainability by translating biosystems into architecture. Drawing inspiration from various sources to address the challenge of the design problem, integrating the behaviour of biosystems into the building envelope could significantly influence energy performance. This paper investigates a bio-mimicry-based approach to enhancing energy efficiency in office buildings by analysing and comparing 8 projects in different climates. The result showed that the behaviour level is more applicable and functional than the organism. And ecosystem levels. Finally, the conceptual model would propose office buildings based on biomimicry strategies.

The current +−0.5 PMV (Predicted Mean Vote) targets adopted by NABERS (National Australian Built Environment Rating System) is the practical range deemed acceptable for 90% acceptability for commercial buildings in Australia, however thermal comfort satisfaction scores measured in office buildings still show high percentages of dissatisfied occupants. This paper aims to demonstrate the potential of curbing energy consumption from commercial buildings in Australia by increasing summer temperature set-points. A 10-year NABERS dataset, along with objective and subjective thermal comfort and air quality data from NABERS-certified offices are investigated in this study. Furthermore, different simulation scenarios are tested to investigate the discomfort hours and energy consumption for various summer temperature setpoints. Result analysis shows that occupants’ satisfaction in NABERS-certified buildings was not within the 90% satisfaction, with being too cold/hot as the main source of dissatisfaction. Objective measurements also showed temperature was out of recommended range for several datapoints. Simulation results indicate that, within the average range of 21–24.9 °C, there is not a significant difference in discomfort hours that could drive the selection of one temperature set-point over the other. Challenging the current practices, results suggest that a cooling set point temperature on the upper limit of the range indicated by the Australian standard AS 1837–1976 may minimize the energy consumption without significantly increasing discomfort, or even increasing the perceived satisfaction with the indoor environment.

This paper provides a simplified analysis method to estimate the impact of building shape on energy efficiency of office buildings in Kuwait. The method is based on results obtained from a comprehensive whole building energy simulation analysis. The analysis takes into account several building shapes and forms including rectangular, L-shape, U-shape, and H-shape as well as building aspect ratios, window-to-wall-ratios, and glazing types. The simplified method is suitable for architects during preliminary design phase to assess the impact of shape on the energy efficiency of office buildings.

Impact of building shape on thermal performance of office buildings in Kuwait

The envelope is one of the most important driving factors in the energy efficiency of buildings. Typical for office and commercial buildings, curtain wall facades allow solar heat gains to be used during the winter but can lead to difficulties in reducing the cooling load during summer. The cooling load is dominant in most building types in the temperate maritime climate, while in the temperate continental climate, it is dominant mainly in office and commercial buildings. The goal of this research was to determine the potential of night passive cooling in an office building model in the most populated urban areas in Croatia-Zagreb and Split, which are located in two different climate zones. Suitable to the climate on-site, an appropriate building envelope and various types of passive and mechanical ventilation systems were selected for each location and case. Additional factors included and analysed were climate conditions, heat gains, the heat accumulation of the building, night ventilation through openings, unwanted air infiltration, and cooling loads. Through a detailed description of the model, passive cooling potential calculations, and Computer Fluid Dynamics (CFD) simulations, the results showed a potential of up to 43.5% savings in the cooling energy need for the temperate continental climate and 32.2% in the temperate marine climate. It was found from the analysis that night ventilation is expected to cool down the building enough to delay a need for cooling by several hours and improve fresh air requirements, thus saving power for cooling, and effectively reducing the need for air conditioning.

Building construction, operation and maintenance altogether account for nearly a third of global carbon emissions. In Hong Kong, buildings contribute to 90% of electricity consumption and 60% of greenhouse gas emissions. Energy efficient building has emerged as an effective approach to reducing energy consumption and carbon emissions. This paper aims to estimate the energy saving potential of different energy efficient measures for office buildings which are an important sector of commercial buildings in Hong Kong. The energy efficient measures were identified using a four-tier framework covering building envelope, building services, renewable energy and human behaviour. The potentials of the measures in reducing energy consumption were estimated using eQUEST Software. The results show that building services and building envelope are the main areas to be addressed for achieving energy efficient office building design. The use of more efficient HVAC systems and low-emissivity windows are revealed as most favored measures for reducing energy consumption of office buildings in Hong Kong. The findings should inform low energy building design in hot and humid subtropical urban environments.

Zone level heating and cooling systems, lighting and blinds in offices have been either controlled by occupants or automated based on fixed setpoints and schedules. Occupants' control of these systems target maintaining a comfortable indoor climate with minimum number of control actions with little intention to save energy. This leads to the suboptimal utilization of daylight and passive solar heat gains. However, when they are automated to mitigate the extravagance in occupant behaviour, operators tend to choose conservative setpoints and schedules that maintain the comfort of the majority and minimize the frequency of complaints with little consideration to save energy again.

When designing a large scale IoT ecosystem, it is important to provide economical solutions at all levels, from sensors and actuators to the software used for analytics and orchestration. It is of equal importance to provide non-intrusive solutions that do not violate users' privacy, but above all, it is important to guarantee the accuracy and integrity of the provided solution. In this work, we present a research prototype solution that has been developed as part of an ongoing project called (EM)3. The project involves IoT sensors and actuators, realtime data analytics modules and cutting edge recommendation algorithms in an ecosystem that improves energy efficiency in office buildings. The main concept of the (EM)3 is to recommend energy saving actions at the right moment to the right user. At the core of the (EM)3 vision is to detect when is the right moment for an energy saving action and sensors play a vital role in this. This article focuses on the model that predicts room occupancy using only data from a motion sensor. The predictions of the model, are used to trigger automations and notifications that turn-off office devices (e.g. air conditioning, lights, monitors, etc.) as soon as the office becomes empty, or a few minutes before this happens, in order to further promote efficient energy consumption habits. The evaluation of the model, using data from a camera sensor for validation, demonstrates a very low error rate and a very short delay on the detection of when the room is actually empty.

Sustainable High-rises

Energy efficient office buildings with passive cooling – Results and experiences from a research and demonstration programme

A study of energy efficiency of private office buildings in Hong Kong

Smart and energy efficient (office) buildings do not only have to implement smart sensors and actuators, they should also be able to be optimized to be as energy efficient as possible based on the behavior of the user. This paper focuses on knowledge extraction of a smart building and automatic rule creation based on that knowledge. We are using different methods to analyze this data, create the appropriate rule set based on the extracted data and based on the correlation and dependencies of different datasets. These methods are also detecting changes in the data (resp. the behavior of the user) and adapts the ruleset accordingly.

Large-scale simulation-based parametric analysis of an optimal precooling strategy for demand flexibility in a commercial office building

Flexibility assessment of a combined heat-power system (CHP) with energy storage under real-time energy price market framework