Search

Strategies to reduce energy consumption are presently experiencing vigorous development. Phase change materials (PCMs) are novel materials that can reduce indoor temperatures via the change in material phase. Regarding the situation in Taiwan, there is no practical utilization of PCMs in school buildings at present, especially in combination with rooftops. In this paper, we discuss the feasibility and utilization potential of installing PCMs in the rooftops of school buildings. School buildings located in northern and southern Taiwan (Taipei and Kaohsiung) were selected to analyze the energy-saving potential and optimization of indoor thermal comfort by installing PCMs with different properties in rooftops over two time periods, including the air conditioning (AC) and natural ventilation (NV) seasons. Based on the simulation results, the feasible patterns of PCM simultaneity are found to be appropriate for improved indoor comfort and energy saving during the different seasons. Specifically, the efficient phase change temperature (PCT) for different PCM thicknesses is clarified to be 29 °C. The economic thickness of PCM was clarified to be 20 mm for Taipei and Kaohsiung. Through the recommendations proposed in this study, it is expected that the PCMs may be efficiently implemented in school buildings to realize the goal of energy conservation and improve thermal comfort.

This research extends Hasan Fathy’s (1986) principle of vernacular architecture by focusing on the Rawshan through an investigation of two criteria: aesthetics and energy efficiency. The paper discusses the views of both the Saudi public and key decision-makers on reviving vernacular architecture in the context of Saudi Arabia’s rapidly developing economy, characterized by relatively high rates of energy consumption and CO2 emissions. This research explores (a) the interaction in domestic buildings of Saudi occupants with their windows, and how these are perceived as an interface with the external environment; (b) awareness and knowledge of the use of shading elements (such as Rawshans) to reduce the use of artificial lighting while maintaining indoor privacy; (c) Saudi awareness of, and familiarity with, the Rawshan as a vernacular element and a secular architectural tradition; and (d) Saudi views on the revival of traditional architectural elements with a focus on the Rawshan. An online survey (n = 812) was conducted across Saudi Arabia complemented by interviews with expert decision-makers (n = 23) to (a) assess criteria such as privacy, aesthetics, daylight, ventilation, and energy consumption in Saudi residences and (b) investigate the level of acceptance of an optimized retrofitted Rawshan design.

Operational uncertainties play a critical role in determining potential pathways to reduce the building energy footprint in the Global South. This paper presents the application of a non-dominated sorting genetic (NSGA II) algorithm for multi-objective building design optimization under operational uncertainties. A residential building situated in a mid-latitude steppe and desert region (Köppen climate classification: BSh) in the Global South has been selected for our investigation. The annual building energy consumption and the total number of cooling setpoint unmet hours (h) were assessed over 13,122 different energy efficiency measures. Six Pareto optimal solutions were identified by the NSGA II algorithm. Robustness of Pareto solutions was evaluated by comparing their performance sensitivity over 162 uncertain operational scenarios. The final selection for the most optimal energy efficiency measure was achieved by formulating a robust multi-criteria decision function by incorporating performance, user preference, and reliability criteria. Results from this robust approach were compared with those obtained using a deterministic approach. The most optimal energy efficiency measure resulted in 9.24% lower annual energy consumption and a 45% lower number of cooling setpoint unmet h as compared to the base case.

Two important factors that have been put in the limelight in the current age are environmental concerns and sustainable future. The building sector has emerged as an important player in this matter due to their contribution into the large share of resources and energy consumption as well as harmful greenhouse gas emission. This paper discusses the percentage of embodied energy (EE) in two common building wall materials in Malaysia: steel and concrete. Concrete is used in concrete non-load bearing walls and steel is used to manufacture curtain walls. Although there are more materials used in the selected case studies, steel and concrete possess the high amount of embodied energy. Thus, the concrete wall and curtain wall in the lifecycle analysis (LCA) pre-use phase in high-rise office buildings in Malaysia are considered in this research. GaBi software is used to evaluate and calculate embodied energy in the case studies. The functional unit for this LCA study is determined as one cubic meter of concrete non-load bearing wall and curtain wall. In order to determine the components included in the analysis, input-output flowcharts are created for each process. The comparison of these walls shows that curtain wall has more embodied energy than concrete. The highest amount of embodied energy in curtain wall construction for case B is 4873.89 MJ, and for the case A is 4851.09 MJ approximately. The amount of EE in the concrete non-load bearing wall for both case studies are the lowest amount, with 278.85 MJ for case A and 280.66 MJ for case B. Results also show that the manufacturing of materials is the biggest contribution to the amount of EE at more than 50%, whereas transportation is between 1.83% and 3.77% only.

As building systems account for almost half of the total energy consumed by the building sector to provide space heating, cooling, and ventilation, efficiently designing these systems can be the key to energy conservation in buildings. Dual VAV systems with an effective control strategy can substantially reduce the energy consumption in buildings, providing a significant scope of further research on this system configuration. This paper proposes to utilize the warm air duct of the dual VAV system as a dedicated outdoor air (DOA) unit when no heating is required, which allows the cooling load to be effectively distributed between two ducts. A specific control sequence is proposed with different supply air temperature reset strategies to estimate the heating, cooling loads, and fan power energy consumption of the proposed system. A simple two-zone office building is taken as a preliminary case study to simulate the airflow rates and fan power of a single duct VAV and proposed dual VAV systems to illustrate the concept. Finally, a larger multi-zone office building is simulated to measure the annual heating, cooling loads, and fan power energy and compare the energy savings among the systems. The results show significant fan power reduction ranging from 1.7 to 9% and notable heating energy reduction up to 76.5% with a small amount of cooling load reduction varying from 0.76 to 2.56% depending on the different locations for the proposed dual VAV systems. Further energy savings from different supply air temperature reset strategies demonstrate the opportunity of employing them according to climates and case studies. The proposed dual VAV system proves to have the potential to be adapted in buildings for the purpose of sustainability and energy savings.

As an efficient measure to protect the environment and reduce energy consumption, promoting prefabricated buildings can lead to the sustainable development of the world economy and long-term economic benefits for society. Nevertheless, for China, it is immature because of the high cost and difficulties in the promotion. The government’s strategies in economy and management are crucial to promoting prefabricated building policies. This paper establishes a quadripartite evolutionary game model composed of construction units, property developers, homebuyers, and government departments under the government supervision system by analyzing the entire interest chain of prefabricated buildings projects. It aims to study the impact of government management and economic strategies on promoting prefabricated building policies. The results show that: (1) The government should ensure the construction safety of projects through mature supervision systems to reduce citizens’ resistant moods caused by project quality problems, (2) The government should improve the reward and punishment mechanism to motivate construction units and developers, (3) The government should invite supervision consulting companies to increase information transparency, avoiding the economic losses of the people and the obstruction of policy implementation caused by information imbalance.

The rural residences of Northwest China are characterized by a state of high energy consumption and low comfort due to the limited economic level and awareness of energy-saving compared with the urban residences. To remedy this, appropriate passive design strategies should be adopted first, in order to provide a design mode with low energy consumption and low cost for rural residences under the premise of thermal comfort. In this paper, taking Hanzhong region (Shaanxi Province, China) as an example, we establish a benchmark model based on a field survey and develop an optimization process by combining EnergyPlus simulation software, the MOBO optimization engine, and weighted sum method. The action mechanisms of passive design parameters, including the building orientation, length–width ratio, building envelope parameters, external shading system, and window–wall ratio, on heating, cooling, and total energy consumption are analyzed, and the quantitative relationships between single-parameter and energy consumption are established. Then, the mutually restricted indices of total energy consumption and initial investment cost are taken as optimization objectives, and 17 design parameters are selected as the optimization variables. The NSGA-II algorithm is adopted to conduct the multi-parameter, multi-objective optimization design for rural houses in Hanzhong area, through coupling of the EnergyPlus and MOBO software. In this way, Pareto solutions are obtained and the value distributions of the multi-objectives and design parameters are analyzed. Based on the actual requirements of decision-makers and using the weight method, three design schemes focusing on different performance tendencies are proposed. The results indicate that by using the proposed optimization process, the building energy consumption can be significantly reduced while taking initial investment costs into account, where the energy-saving rate is in the range of 31.9–61.5%. When the EC/IC ratio is 1:1, 2:1, and 1:2, the energy-saving rate can reach 51.5%, 57.8%, and 43.5%, respectively. It can provide a beneficial pattern for the energy-saving design and renovation of rural residences in Hanzhong area of China.

This paper proposed an optimization method to minimize the building energy consumption and visual discomfort for a passive building in Shanghai, China. A total of 35 design parameters relating to building form, envelope properties, thermostat settings, and green roof configurations were considered. First, the Latin hypercube sampling method (LHSM) was used to generate a set of design samples, and the energy consumption and visual discomfort of the samples were obtained through computer simulation and calculation. Second, four machine learning prediction models, including stepwise linear regression (SLR), back-propagation neural networks (BPNN), support vector machine (SVM), and random forest (RF) models, were developed. It was found that the BPNN model performed the best, with average absolute relative errors of 3.27% and 1.25% for energy consumption and visual comfort, respectively. Third, six optimization algorithms were selected to couple with the BPNN models to find the optimal design solutions. The multi-objective ant lion optimization (MOALO) algorithm was found to be the best algorithm. Finally, optimization with different groups of design variables was conducted by using the MOALO algorithm with the associated outcomes being analyzed. Compared with the reference building, the optimal solutions helped reduce energy consumption up to 34.8% and improved visual discomfort up to 100%.

During the summer, the environmental impact of building operations can be reduced by optimizing ventilation and preventing heat from entering the building. Shades are used to create a comfortable temperature state in interiors without operating mechanical equipment or using low-power systems. The most significant factor in reducing energy consumption would be if the spatial delimitation of buildings utilizes solar energy in a passive or active way. At the same time, limiting the energy entering through windows reduces the temperature of interiors and the amount of energy used for cooling; thus, the phenomenon of the urban heat island would be less exacerbated. In the case of existing historical buildings, there are limited possibilities to reduce the energy consumption of the building and to protect the buildings against excessive summer heating, especially in connection with the structural appearance of the doors and windows on the façade. This paper presents the preparation of a large-scale reconstruction project based on a newly developed combined window that can significantly reduce indoor summer overheating. Designing steps of the complex retrofitting of a traditional box-type window are highlighted based on the results of closely connected literature pertaining to thermal, ventilation, shading, and acoustical phenomena. The result is a detailed structural and technological design of the reconstruction for the historical window in a combined way, as the frame, glazing, ventilation, and shading are simultaneously developed and calculated approximately; moreover, active shading is integrated. One aim of this desktop study was to demonstrate that in the case of historical buildings, it is possible and necessary to reduce heat losses during the heating season and to minimize the risk of summer overheating, and to show that the surface of the façade could be converted into an energy producer.

Improving the energy efficiency of existing buildings by implementing building automation control strategies (BACS) besides building envelope and energy system retrofitting has been recommended by the Energy Performance of Buildings Directive (EPBD) 2018. This paper investigated this recommendation by conducting a simulation-based optimization to explore cost-effective retrofitting combinations of building envelope, energy systems and BACS measures in-line with automation standard EN 15232. Two cases (i.e., a typical single-family house and apartment block) were modeled and simulated using IDA Indoor Climate and Energy (IDA-ICE). The built-in optimization tool, GenOpt, was used to minimize energy consumption as the single objective function. The associated difference in life cycle cost, compared to the reference design, was calculated for each optimization iteration. Thermal comfort of the optimized solutions was assessed to verify the thermal comfort acceptability. Installing an air source heat pump had a greater energy-saving potential than reducing heat losses through the building envelope. Implementing BACS achieved cost-effective energy savings up to 24%. Energy savings up to 57% were estimated when BACS was combined with the other retrofitting measures. Particularly for compact buildings, where the potential of reducing heat losses through the envelope is limited, the impact of BACS increased. BACS also improved the thermal comfort.

© 2018 by the authors. Globally, only 2% of existing building stock is built yearly; the remaining 98% already exist. Energy consumption and indoor thermal comfort of the existing building stock are not encouraging. This is due to many challenges associated with existing buildings; the challenges range from cracks, leakages, poor insulation, heat losses and high rate of unsustainable technologies. This paper investigates possible barriers facing the adoption and application of sustainable technologies (STs) for sustainable or energy-efficient upgrade of existing buildings. New STs are manufactured on a regular basis to meet improved energy efficiency standards, yet there are minimal actions/attempts to adopt and apply improved technologies in existing buildings for energy efficiency. Indeed, there are limited studies focused on the use of qualitative approaches to identify barriers to adoption and use of STs. Thus, a semi-structured interview approach was adopted and applied using sustainability/energy efficiency professionals, building services engineers, project managers, architects, and facility managers in Australia. The results indicate that barriers to the adoption and application of sustainable technologies are perceived benefits in demolish-and-build, age of building, cost of STs, perceived poor payback time, unreliable energy-savings projections, existing design, hidden and overall cost of renovation, and cost of STs.

In this paper, the effect of an exterior shading element (Iwan) on energy consumption in four different climatic regions and for different orientations, has been investigated numerically and experimentally. By applying different materials and techniques and creating various elements and spaces, architects make hard climatic conditions more tolerable for residents. Iwan is one of the cooling elements which is used in different forms and dimensions in the Islamic architecture. In the present research, Iwan has been introduced as a climatic element in traditional and contemporary architectures and its role in reducing the energy consumption in buildings has been studied. In this respect, first, the thermal loads of a building without Iwan are computed using the EnergyPlus software. Then, four different forms of Iwan are added to the above-mentioned structure along the four principal orientations, moreover, the effect of Iwan on the reduction of thermal loads is analyzed for four different climates. Finally, the design parameters of Iwan, in terms of depth and form, which can help reduce the thermal loads in different climatic conditions are presented. The results show that the best position for using an Iwan is the south direction and the use of Iwan in temperate & humid, hot & humid, cold & mountainous and hot & dry climates could reduce the energy consumption in buildings by 32%, 26%, 14% and 29%, respectively.

It is well known that the Gulf Cooperation Council (GCC) of countries resides at or close to the top of the global table of CO2 emissions per capita and its economy relies heavily on its fossil fuels. This provides a context for green building programs that initially aim to create an understanding of emission pathways within the GCC and hence develop approaches to their reduction in the built environment. A set of criteria will allow specific analysis to be undertaken linked to the spatial dimensions of the sector under study. In this paper, approaches to modelling energy consumption and CO2 emissions are presented. As investment in the built environment continues, natural resources dwindle and the cost of energy increases, delivering low-energy buildings will become mandatory. In this study, a hybrid modelling approach (bottom-top & top-bottom) is presented. Energy benchmarks are developed for different buildings’ uses and compared with international standards. The main goals are to establish design benchmarks and develop a modelling tool that contains specific information for all buildings types (existing and new), as well as planned and projected growths within the various city districts, then integrate this database within a geospatial information system that will allow us to answer a range of “what-if”-type questions about various intervention strategies, emissions savings, and acceptability of pre-defined course of actions in the city sector under consideration. The spatial carbon intensity may be adjusted over a certain period, (e.g., through local generation (microgeneration)) or due to an increasing proportion of lower carbon-energy in the generation mix and this can be related to the sector and city overall consumption.

Load forecasting plays a major role in determining the prices of the energy supplied to end customers. An accurate prediction is vital for the energy companies, especially when it comes to the baseline calculations that are used to predict the energy load. In this paper, an accurate short-term prediction using the Exponentially Weighted Extended Recursive Least Square (EWE-RLS) algorithm based upon a standard Kalman filter is implemented to predict the energy load for blocks of buildings in a large-scale for four different European pilot sites. A new software tool, namely Local Energy Manager (LEM), is developed to implement the RLS algorithm and predict the forecast for energy demand a day ahead with a regular meter frequency of a quarter of an hour. The EWE-RLS algorithm is used to develop the LEM in demand response for blocks of buildings (DR-BOB), this is part of a large-scale H2020 EU project with the aim to generate the energy baselines during and after running demand response (DR) events. This is achieved in order to evaluate and measure the energy reduction as compared with historical data to demonstrate the environmental and economic benefits of DR. The energy baselines are generated based on different market scenarios, different temperature, and energy meter files with three different levels of asset, building, and a whole pilot site level. The prediction results obtained from the Mean Absolute Percentage Error (MAPE) offer a 5.1% high degree of accuracy and stability at a UK pilot site level compared to the asset and whole building scenarios, where it shows a very acceptable prediction accuracy of 10.7% and 19.6% respectively.

This paper investigates various building material effects on the cooling load requirements of a typical two-floor house located in the Midwest region in the USA. A survey was done for various building materials along with their prices in the US market. Various building walls, lighting, window glazing, and insulations were used for simulation as single and combined cases. The return on investment from savings in the electrical load consumption against the materials cost was investigated. It was found that the best single case savings and investments were for cases when lights were changed from incandescent lighting with 20 W/m2 to fluorescent bulbs, or when using double skinned walls with 5 cm rock wool or expanded polystyrene insulation. Combined cases, combining more than one single change, offered more reductions in cooling loads but were associated with higher initial costs and, thus, longer returns on investment. The best case recommendation was for buildings with a 20 cm hollow concrete block (HCB) when combined with fluorescent lights and double pane heat-absorbing glazing for windows. Although these recommendations were for a typical house in the Midwest region of the United States, a similar analysis could be adopted by designers and building owners to optimize the energy consumption in their buildings. The final design decision should be based on an optimum correlation of the air-conditioning units&rsquo, size and cost, running and maintenance costs, the return on the investment duration, and the available usage area in the building.

This study examines the need in mild maritime climates, such as the southern areas of the UK, for mechanical ventilation with heat recovery (MVHR) as required by the German Passivhaus standard. It considers the comfort, air quality and energy impacts of MVHR versus natural ventilation and reviews the post-occupancy monitoring data of two flats in Cardiff designed to Passivhaus standards, one of which had been operated as a naturally ventilated building rather than with MVHR. The energy consumption of this free-running flat was significantly lower (36 kWh primary energy/m²a) than the Passivhaus Planning Package modeling had predicted (93 kWh primary energy/m²a) with no adverse effects on occupant comfort, air quality or excessive humidity, and advantages of lower capital cost and maintenance. The paper concludes that in climates with mild winters and cool summers the use of MVHR could be omitted without compromising comfort levels and achieving at least equivalent energy savings resulting from adopting the Passivhaus model and at a lower capital cost. This suggests the potential for a naturally ventilated, ultra-low energy model with lower capital investment requirements and lower disruption when applied to retrofit that would facilitate its mainstream adoption.

Since buildings account for 40% of total energy consumption and 36% of CO2 emissions in the European Union (EU), the directive 2010/31/EU &ldquo, Energy Performance of Buildings Directive (EPDB)&rdquo, among other legal provisions concerning the reduction of energy consumption of buildings has been enforced. According to this legislation, all new buildings must be nearly zero energy buildings &ldquo, nZEB&rdquo, by 31 December 2020 (public buildings by 31 December 2018). Nonetheless, the assessment of the &ldquo, high energy performance&rdquo, of a building is ambiguous and a cross country comparison seems to be intricate since different national building codes and nZEB definitions employ different energy indicators and methods. This paper delves into the question of how do the ambition levels of &ldquo, definitions and the transposition of the Directive 2010/31/EU into national law differ in four selected EU Countries: Austria, Germany, Spain, and England (as part of UK). The energy performance of some exemplary buildings is assessed by means of a simplified MATLAB model that is based on the norm DIN V-18599. The results drawn from this work show how diverse are building codes scopes and national &ldquo, definitions. Only 9 of the 36 studied cases of residential buildings obtain consistently the &ldquo, compliance status in all four selected countries. The results show that climate conditions, energy requirements, primary energy factors, ambition levels, and calculation methodologies lead to the problem of an uneven cross-country comparison. Moreover, primary energy consumption [kWh/m2a] set as the main quantitative energy indicator by the directive 2010/31/EU might not be the most suitable one for an EU level comparison.

This study simulates an increased thermal capacitance (ITC) and thermal storage management (TSM) system to reduce the energy consumed by air conditioning and heating systems. The ITC/TSM is coupled with phase change materials (PCM), which enable tank volume reduction. The transient energy modeling software, the Transient System Simulation Tool (TRNSYS), is used to simulate the buildings&rsquo, thermal response and energy consumption, as well as the ITC/TSM system and controls. Four temperature-controlled operating regimes are used for the tank: building shell circulation, heat exchanger circulation, solar panel circulation, and storage. This study also explores possible energy-saving benefits from tank volume reduction such as losses associated with the environment temperature due to tank location. Three different tank locations are considered in this paper: outdoor, buried, and indoor. The smallest tank size (five gallons) is used for indoor placement, while the large tank (50 gallons) is used either for outdoor placement or buried at a depth of 1 m. Results for Atlanta, Georgia show an average 48% required energy decrease for cold months (October&ndash, April) and a 3% decrease for warm months (May&ndash, September) for the ITC/TSM system with PCM when compared with the reference case. A system with PCM reduces the tank size by 90% while maintaining similar energy savings.

Educational buildings could play leading roles in increasing high-performance building refurbishments across Europe. The city of Vienna has substantially modernized its schools in the last decade, however mostly single refurbishment measures have been undertaken. This is missing the potential of comprehensive and more energy-efficient actions as well as functional adaptations, which become ever more important as school and learning systems are changing. Institutional framework conditions, budget constraints as well as the lack of a coherent methodology have been identified as the main barriers in this context. The research question addresses how qualitative aspects, such as architecture and function, as well as quantitative aspects, such as energy consumption, could be combined in a methodology that can be easily applied by relevant stakeholders. What would a methodology that actively supports stakeholders in their decision-making process for more comprehensive school refurbishments look like? This paper describes a potential approach and its application in a case study. The proposed methodology supports the development of energy- and functionally optimized refurbishment concepts, with a focus on the synergies between energy-related optimizations and state-of-the-art functional room concepts in order to do justice to the changing learning requirements in schools.

Green roofs may be considered a passive energy saving technology that also offer benefits like environmental friendliness and enhancement of aesthetic and architectural qualities of buildings. This paper examines the energy and economic viability of the green roof technology in the hot humid climate of Saudi Arabia by considering a modern four bedroom residential building in the city of Dhahran as a case study. The base case and green roof modelling of the selected building has been developed with the help of DesignBuilder software. The base case model has been validated with the help of 3-month measured data about the energy consumption without a green roof installed. The result shows that the energy consumption for the base case is 169 kWh/m2 while the energy consumption due to the application of a green roof on the entire roof surface is 110 kWh/m2. For the three investigated green roof options, energy saving is found to be in the range of 24% to 35%. The economic evaluation based on the net present value (NPV) approach for 40 years with consideration to other environmental advantages indicates that the benefits of the green roof technology are realized towards the end of the life cycle of the building.

This paper examined the influences of the built environment and socio-economic driving factors on domestic gasoline consumption in developing metropolitan regions through a case study of the greater Cairo metropolitan region (GCMR), Egypt. Structural equation modeling (SEM) was used in analyzing the causality of the domestic gasoline consumption. The influences of major factors hypothetically affecting the domestic energy consumption such as resident characteristics and built environment characteristics were examined. The results proved a high positive influence of the resident’s income and the number of adults as driving factors, directly and indirectly, affecting energy consumption levels. Population density and attitude towards eco-friendly driving factors proved to be a very low influence on energy consumption. The built environment driving factors such as access time to public transportation and related building characteristics factors proved to have a low impact on energy consumption. The study findings suggest that the design of a built environment should be well related to the socioeconomic factors to manage the domestic energy consumption in developing regions.