Energy Performance Simulation Research Articles

Annual energy performance simulation of ground source heat pump in a solar greenhouse

The use of ground source heat pumps (GSHP) in solar greenhouses had the potential to improve energy efficiency and reduce carbon emissions. However, because of the imbalance in cooling and heating applications, there would be an imbalance of heat in the subsoil. A numerical model of GSHP in a tomato growing solar greenhouse was created based on EnergyPlus. Annual energy performance simulations were performed with borehole free cooling, ground source heat pump cooling and heating operation modes. Thermal balance of the subsoil was achieved by adjusting the operating strategies of the three modes. Simulation results showed that the average COP of heating and COP of cooling of GSHP were 4.66 and 5.35 respectively.

Computational Design for Multi-Optimized Geometry of Sustainable Flood-Resilient Urban Design Habitats in Indonesia

Unfortunately, flooding is a major worldwide problem that especially affects low-lying cities like Semarang, Indonesia. Therefore, this study focuses on the flood-prone areas of Semarang, where recurring high tides and surges from severe precipitation cause havoc. In order to create water-resistant dwelling topologies, the paper explores the early incorporation of computational design approaches. Ultimately, the objective is to explore the strategic application of generative design techniques to support the development of a highly adaptive urban environment using optimization-based data-driven design approaches. With careful consideration, advanced computational methods were used to find concepts that may manage and lessen possible consequences in an efficient manner, increasing the urban landscape’s overall flexibility. Achieving the best possible solutions, which consider issues like feasibility, sustainability, durability, adaptability, and user comfort, requires the application of computational studies such as microclimatic, rainfall, energy performance, and fluid simulations. Consequently, promising advances in water retention and trajectory control features are shown by evaluations that concentrate on wind dynamics and energy considerations. One such example is GEN_8, the most optimal typology produced by additive massing approaches. In addition to showing less water retention than usual building typologies, GEN_8 optimizes energy performance to improve user experience overall. Accordingly, the computationally created geometry GEN_8’s shaded areas and facades effectively account for between 191.4 and 957 kWh/m2 of yearly solar radiation. In contrast, average building typologies show higher amounts of annual solar radiation, with a minimum of 574.32 kWh/m2 and a maximum of 1148.65 kWh/m2. This paper’s comprehensive approach not only addresses worldwide issues but also highlights how computational design techniques may be used to construct, assess, and validate workable solutions for flood-prone locations within a flexible framework that has been painstakingly designed. As a result, the research also highlights the significance of technological advancements and computational tools in assessing, producing, and validating workable solutions for flood-prone locations by carefully curating a flexible framework that ensures efficiency, comfort, and design optimization.

Multi-objective optimization of energy and daylight performance for school envelopes in desert, semi-arid, and mediterranean climates of Iran

Considering global warming as a critical challenge to human life, performance optimization of the building envelope can play a noticeable role to reduce a building's environmental footprint. Meanwhile, shading systems are considered as sustainable passive solutions to contribute to building energy efficiency, and daylight control in early-stage design. Nonetheless, a paucity of research has examined the various shading strategies in diverse climates, particularly arid desert and steppe regions, in conjunction with educational buildings. The present study aims to evaluate the role of fixed exterior shading systems (FESSs), and window-to-wall ratio (WWR) on building’ thermal and daylight performance in Iran with desert, semi-arid, and Mediterranean climates. Pareto Frontier and weighted-sum method for multi-objective optimization, and sensitivity analysis were used to study the optimum solutions, and the relationship between the design variables and the performance metrics. Three objective metrics including Spatial Daylight Autonomy (sDA), Annual Sunlight Exposure (ASE), and Energy Use Intensity (EUI), were defined as performance metrics. Shadings include vertical louver, horizontal louver, light shelf, overhang, and egg-crate. The results showed that EUI was reduced via FESS-integrated façade by 25.22%, 20.84%, 19.14%, 14.06%, and 13.47%, in Yazd, Bushehr, Kerman, Rasht, and Mashhad as selected studied cities, respectively. Based on ASE, the horizontal louver surpasses the other systems by 100% ASE value reduction in all climate zones except for Rasht. sDA level is reduced in all climate zones considering five studied FESSs excluding horizontal louver in Yazd and Rasht and overhang in Mashhad by 100% sDA level. Building energy performance simulation is validated by ASHRAE140-2020.

Sensitivity Assessment of Building Energy Performance Simulations Using MARS Meta-Modeling in Combination with Sobol’ Method

Large discrepancies can occur between building energy performance simulation (BEPS) outputs and reference data. Uncertainty and sensitivity analyses are performed to discover the significant contributions of each input parameter to these discrepancies. Variance-based sensitivity analyses typically require many stochastic simulations, which is computationally demanding (especially in the case of the large number of input parameters involved in the analysis). To overcome these impediments, this study proposes a reliable meta-model-based sensitivity analysis, including validation, Morris’ method, multivariate adaptive regression splines (MARS) meta-modeling, and Sobol’ method, to identify the most influential input parameters on BEPS prediction (annual energy consumption) at the early building design process. A hypothetical building is used to analyze the proposed methodology. Six statistical metrics are applied to verify and quantify the accuracy of the model. It is concluded that the cooling set-point temperature and g-value of the window are the most influential input parameters for the analyzed case study.

ADOBE BRICKS TO HOLLOW SANDCRETE BLOCK WALLING IN TROPICAL BUILDING CONSTRUCTION: MATERIAL IMPACT ON SUSTAINABLE INDOOR THERMAL COMFORT ATTAINMENT

Introduction: Tropical climate is characterized by high temperature, the consequence of which induces indoor thermal discomfort. This is attributed to high solar gains through various elements of the building envelope, including windows, walls, and roof among others. However, in an attempt to optimize indoor thermal comfort with minimal or no recourse to mechanical installations, this study explores the roles of the walling fabrics by comparing varying thermo-physical properties of two identified masonry units in the study area of Ogbomoso, Nigeria (adobe bricks and hollow sandcrete blocks), with a view to identifying a more thermally comfortable and sustainable material option. The methodology involves virtual models of two similar residential buildings each composed of either adobe bricks or sandcrete blocks, as masonry units. These models were subjected to energy performance simulation analyses using DesignBuilder software, over a 12‑month cycle period, to experience year-round differential thermal conditions. Through the observed comparative annual heat loads as experienced in the models, the results show improved indoor thermal comfort in the brick building (i.e., 7119.54 KWh), with heat loads being 11% lower than that of the sandcrete building (i.e., 8875.65 KWh) due to the brick walling fabric. This may be associated with the brick’s lower thermal conductivity (U-Value) of 1.798 W/m2-K, compared with the sandcrete blocks’ value of 1.999 W/m2-K. Results: In general, adobe bricks as a walling unit exhibit more thermal resistance against the harsh outdoor weather conditions than sandcrete blocks. The study is part of an ongoing effort towards reviving this partially neglected low impact material — adobe brick — with a view to attaining sustainable indoor thermal comfort as well as protect the environment in the study area.

Multi-criteria decision support framework for climate change-sensitive thermal comfort evaluation in European buildings

This paper proposes a novel multi-criteria decision support framework for climate change-sensitive evaluation of building thermal comfort performance in European buildings. The proposed framework considers various comfort categories based on building use and condition, comfort models based on building operation, sensitivity to climate change, key performance indicators, and their thresholds. The proposed framework is then implemented using a passive house-certified high-performance timber dwelling near Brussels as a case study. The thermal comfort in the free-running reference timber dwelling is assessed using a whole-building energy performance simulation model with a static threshold of 26°C for the bedrooms and an adaptive threshold for the other occupied zones. The analysis found an increase in indoor overheating degree by 1.7°C and ambient warmness degree by 6.5°C during heat waves from the current scenario to the end of the century scenario. However, the reference timber dwelling effectively suppressed the impacts of climate change with varying degrees of success towards the end of the century. The proposed framework is intended to support decision-makers in effectively evaluating performance during the early stages of building design. The study highlights the need for further research on building performance assessment techniques and guidelines in a changing climate.

Enhancing energy efficiency and comfort with a multi-domain approach: Development of a novel human thermoregulatory model for occupant-centric control

Occupant Centric Control (OCC) strategies aims to achieve a more personalized and comfortable indoor environment, translating occupants' comfort requirements into real environmental conditions. This strategy relies on a multilevel non-linear programming optimization procedure to determine optimal thermo-hygrometric setpoints. The objective is to minimize space heating and cooling requirements while addressing multi-domain comfort concerns related to individual thermal sensations and perceived air quality. To facilitate this process, this study adopts a novel Personal Comfort Model (PCM), incorporating physiological factors to predict occupants' thermal sensations and CO2 intakes. The PCM's reliable predictive capabilities are confirmed through validation with real experimental data from a test room at the University of Perugia. For detailed energy analyses, considering occupants' subjective comfort preferences, the PCM is seamlessly integrated into DETECt, an in-house building energy performance simulation tool developed by the University of Naples Federico II, for the design of advanced control algorithms and energy efficiency strategies. To effectively manage the HVAC system, a model predictive control is implemented, using the determined setpoints to ensure mechanical ventilation and maximize cost savings. The proof of concept for the developed methodology involves simulating experimental tests using the thermal model of the human body and the new facility management system, to be simulated and optimized by means of the enhanced building energy performance simulation tool, exploited for the design and operation of more occupant-centric and sustainable buildings. The proposed study demonstrates that through the developed OCC strategy enables a significant reduction in thermal discomfort (40 % and 60 % less than the occupation time for test 1 and test 2, respectively) compared to reference scenarios. Additionally, energy analysis reveals high efficiency, achieving savings of 12.8 % and 7.8 % of electricity consumed for HVAC system operation.

Solar neighborhoods: the impact of urban layout on a large-scale solar strategies application

The article addresses the challenges of evaluating energy performance in different neighborhood settings under various energy efficiency measures and proposes a methodology for selecting appropriate solar strategies on a neighborhood scale. The study selects five representative neighborhoods from various climatic zones with different building and street layouts. The proposed methodology involves a systematic three-step multi-domain workflow for implementing energy efficiency measures and solar strategies in the existing neighborhoods. The first step involves typical energy performance simulation, the second step involves energy simulation using high performance building envelope, and the third step involves the addition of solar strategies in combination with retrofitting materials to achieve net-zero status. The results of the study show that modifying the building envelope leads to a significant reduction in energy consumption, with up to 60% reduction observed. The study also finds that the optimal mix of solar strategies depends strongly on the type of neighborhood, its street layouts, and the type of buildings. The article highlights the importance of considering these factors when implementing solar strategies on a neighborhood scale to achieve energy efficiency and net-zero status. It provides urban planners with a systematic decision-making approach to evaluate and optimize neighborhoods to achieve net-zero energy status.

Assessing the impact of morphed CMIP6 climate model outputs on building energy performance simulations

In this paper we utilise the latest generation of climate change models from Climate Model Intercomparison Project 6 (CMIP6) to morph typical meteorological year (TMY) weather files. These morphed files are used in conjunction with a standard set of reference models for the climate zones in the United States. Building energy demand, comfort, and photovoltaic (PV) yield are all simulated and evaluated for how they can be expected to change under each climate scenario. We find that the shifts in various preference metrics may vary seasonally in both magnitude and direction. Additionally, the overall distribution of the change can be highly variable across the US climate zones. The results indicate that buildings, as designed now, may not be able to provide comfortable conditions in the future. Furthermore the impact of increased cooling demand will change how building-based PV electricity yield is utilised.

Life Cycle Assessment and Building Information Modeling Integrated Approach: Carbon Footprint of Masonry and Timber-Frame Constructions in Single-Family Houses

The analysis of the carbon footprint of buildings is a key tool for assessing the impact of different buildings on climate change. Several frameworks and methodologies are available to calculate the footprint of buildings, including standards and norms, Life Cycle Assessment (LCA), and dedicated software tools. The use of Building Information Modeling (BIM) programme for these calculations is both scientifically justified and very practical. This scientific publication focuses on the application of a BIM-based research methodology to analyse the carbon footprint of a single-family house. The research process included the following steps: (i) the design of a single-family house with masonry construction using Archicad 26, BIM programme, (ii) simulation of the building energy performance using the EcoDesigner Star plug-in, (iii) LCA using the plug-in for Archicad, (iv) preparation of a second model with timber-frame construction for comparison, and (v) comparative analysis of the single-family house models with masonry construction (building A) and timber-frame (building B). Analysis of the results highlights significant differences in CO2e emissions between buildings and the varying impact of individual elements on the total CO2e emissions of the buildings studied. Building A had significantly higher net emissions, amounting to 43,226.94 kg CO2e, in stark contrast to Building B’s significantly lower 13,522.13 kg CO2e. This discrepancy was also mirrored in the emission intensity, with Building A emitting at a rate of 281.06 kg CO2e/m2 compared to Building B’s 96.72 kg CO2e/m2. These findings are relevant for future work on sustainable building design and construction aiming to minimise negative environmental impacts. The goal of minimising the cumulative carbon footprint of buildings is critical to achieve the Sustainable Development Goals and combating climate change.

Feasibility analysis of the application of building automation and control system and their interaction with occupant behavior

Occupant behavior is among the main causes for the mismatch between simulated and in-use energy performance of buildings. One of the strategies considered capable of reducing user’s behavior induced energy consumption, while increasing indoor environmental quality is the application of Building Automation and Control Systems (BACS). In this study, three building user’s profiles have been considered depending on their energy consumption. The energy savings due to BACS class increase have been calculated, and a cost–benefit analysis (CBA) has been performed to evaluate the feasibility of different scenarios. Additional co-benefits perceived by the individuals have been accounted for in the form of willingness-to-pay (WTP). The methodology is applied to two case studies: a nearly zero-energy building (NZEB) rural single-family house and a recently renovated dwelling in an apartment block. The results show that the main reductions are achieved by the users’ behavior alone, and the adoption of BACS is economically feasible only when an incentive program is in place, and the WTP is repeated as a recurrent co-benefit over the years. In particular, relying only on energy reduction due to higher BACS class introduction is not economically desirable. The greatest savings are achieved by the behavioral change of the user when coupled with BACS, supporting their potential role in improving user’s energy literacy. Finally, incentive schemes are necessary to reduce the investment costs of such projects, being these the most influential variables in the feasibility of BACS applications.

Between Fancy and Functionality: Comparative Thermal Performance Analyses of Selected External Building Shading Elements in Tropical Building Design

Tropical region is characterized by high temperature, arising from high solar radiation. Incoming near-infrared energy emanating from excessive direct sunlight leads to increase in the indoor temperature with its attendant indoor thermal discomfort. Thus, there is the need for protection of the interior from this excessive direct heating. One of such protective approaches is the introduction of exterior shading elements to block the incoming solar energy. To achieve this in a typical tropical city of Ogbomoso, Nigeria, several forms of exterior window shading elements are adopted predominantly based on individual preferences, fancies, etc., without scientific consideration for their effectiveness. This study therefore investigated performance effectiveness of each type, with a view to identifying the most effective shading element in the study area. The study adopted the use of multiple/iterative building performance simulation tool, DesignBuilder for evaluating indoor thermal performance of a typical three-bedroom residential building, with regard to four predominantly adopted fixed external shading elements in the study area. Virtual models of five variants of the building were subjected to energy performance simulation analysis, using weather data for Ogbomoso. While the first building tagged Building I was modelled without any shading element, to serve as the control building, the remaining four tagged Building II, Building III, Building IV and Building V were modelled with overhangs, side-fins, hybrids and louvres shading system respectively. Building V recorded highest reduction (56.55%) in the indoor solar gains. This was followed in the order of Building IV (23.90%), Building II (16.00%), and Building III (7.63%). Thus, effectiveness of external louvres system as an external shading device over side-fins and overhangs in the study area could be established. This research is necessary to minimize additional active energy required to reduce the indoor thermal discomfort arising from solar gains (through reduced annual space cooling loads). This will increase building energy efficiency and reduce carbon emissions for overall clean and safe global environment

A comprehensive model considering multiple types of occupant behavior for building energy performance prediction and simulation – taking a university campus as an example

Occupant behavior, encompassing occupant numbers and actions, significantly contributes to the uncertainty of building energy performance simulation. By characterizing the regularity of occupant behavior, it becomes feasible to evaluate its impact on building energy consumption and mitigate disparities between simulated and measured outcomes. This paper presents a comprehensive model that integrates two key aspects of occupant behavior to predict and simulate energy performance in campus buildings. The model introduces two distinct categories of equipment, namely environment-related equipment (e.g. lighting, air conditioning) and time-related equipment (e.g. water dispenser, printer), to account for the diverse factors that influence occupant behavior. The impact of occupant perception on the environment is considered to enhance simulation accuracy. Furthermore, this study compares the proposed model with models that consider only occupant number or occupant energy use behavior individually to assess its effectiveness in capturing the complexities of occupant behavior in energy performance simulations.

A New Approach in Daylighting Design for Buildings

Daylighting is a future building design trend, subjected to all the global energy efficiency standards, but its design still largely depends on the architect and it is difficult for electrical engineers to precisely quantify the energy efficiency of the solution. This study presents an innovative integration process of design and simulation, rooted in the parameters of existing standards and regulations, and leveraging architectural design and simulation software tools. Within this novel integrated design methodology, the peripheral zones of the building envelope and the central core areas of the structure are discretely conceptualized and designed. Daylight intensity in the building envelope’s peripheral zones is calculated based on the average daylight factor and the building’s optimized window-to-wall ratio. In contrast, the central core areas are designed to attract daylight from open spaces on the roof, roof structure, reflective roofs, and clerestories. A building energy performance simulation tool is utilized to validate the energy efficiency of these new design techniques. This fresh approach is tested on a complex pilot-scale building in Nhon Trach, Dong Nai, Vietnam, to evaluate the method’s feasibility and scientific soundness. The simulation results corroborate the accuracy of the proposed approach in quantifying the efficiency of reducing a building’s lighting system energy consumption by 34%, equivalent to an annual CO2 saving of over 4,000 tons. Through the proposed daylighting design, an approximate 7% increase incurs in total initial investment, promising substantial profitable returns.

Simulated and monitored electrical energy balance in a solar house in Dubai, UAE

ABSTRACT This paper presents the energy performance simulation and monitoring of a solar powered house designed, built, and operated under Dubai's hot and humid climate, stressing the balance between the electricity consumption and the production of the roof PV system. The study shows a summary of the design process aimed at optimizing the house’s energy performance and maximizing the direct use of solar energy in the specific UAE climatic scenario, which implies a consistent use of cooling throughout the year. The simulated and monitored data collected by a third-party organization grants the reliability of the analysis on the real case study. The comparison of the predicted and monitored PV production shows a moderate gap, primarily due to the variable climatic conditions, but ultimately confirms the efficiency and feasibility of the system.

An Integrated Decision-Making Framework for Mitigating the Impact of Urban Heat Islands on Energy Consumption and Thermal Comfort of Residential Buildings

Urban heat island (UHI) is a zone that is significantly warmer than its surrounding rural zones as a result of human activities and rapid and dense urbanization. Excessive air temperature due to the UHI phenomenon affects the energy performance of buildings and human health and contributes to global warming. Knowing that most of the building energy is consumed by residential buildings, therefore, developing a framework to mitigate the impact of the UHI on residential building energy performance is vital. This study develops an integrated framework that combines hybrid micro-climate and building energy performance simulations and multi-criteria decision-making techniques. As a case study, an urban area is analyzed under the Urban GreenUP project funded by the European Union’s Horizon 2020 Programme. Four different strategies to mitigate the UHI effect, including the current situation, changing the low-albedo materials with high-albedo ones, nature-based solutions, and changing building façade materials, are investigated with a micro-climatic simulation tool. Then, the output of the strategies, which is potential air temperature, is used in a dynamic building energy simulation software to obtain energy consumption and thermal comfort data of the residential buildings in the case area. Finally, a multi-criteria decision-making model, using real-life criteria, such as total energy consumption, thermal comfort, capital cost, lifetime and installation flexibility, is used to make a decision for decreasing the UHI effect on residential energy performance of buildings. The results showed that applying NBSs, such as green roofs and changing existing trees with high leaf area density ones, have the highest ranking among all mitigation strategies. The output of this study may help urban planners, architects, and engineers in the decision-making processes during the design phase of urban planning.

Climate change impacts on heating and cooling energy demand in residential building units. Application in the city of Thessaloniki, Greece

The present study aims to evaluate the effect of climate change on the heating and cooling energy needs of a residential building unit, located in the city of Thessaloniki, Greece. Future weather files have been generated using both statistical and dynamical downscaling methods. In the first case, the Meteonorm weather generator was used to generate a future weather file, while for the dynamic downscaling approach, the Hadley Regional Model 3 (HRM3), coupled with Hadley Climate Model 3 was employed. The generated future weather datasets have been then used as an input parameter in the dynamic energy performance simulations of the residential building unit with Energy Plus. For all examined weather datasets, the simulation results show a decrease of the heating energy use, an effect that is strongly counterbalanced by the rise of the cooling energy demand.

A Numerical Study on the Exergy Performance of a Hybrid Radiant Cooling System in an Office Building: Comparative Case Study and Analysis

This research investigated the exergy enhancement performance of a hybrid radiant cooling system adapting to a hot and humid summer conditions through comparative case studies and analyses. This study suggested three cooling systems: a general all-air system (AAS), a conventional radiant cooling system (CRCS), and a hybrid radiant cooling system (HRCS). As a case study, an office building with cooling systems was examined in the summer season in four different cities: Beijing, Shanghai, Chengdu, and Guangzhou, China. This study utilized the building energy performance simulation program to analyze the cooling loads of office space in a building with numerical approaches. The comparison analysis using the four different weather datasets showed simple and rational exergy efficiency and the overall impact ratio. According to the results, the ambient conditions, i.e., the surrounding temperature and the humidity ratio, significantly impacted the cooling systems’ exergy efficiency ratio. On the basis of the calculated energetic and exergetic performance, the HRCS had a higher exergy efficiency and a higher overall impact ratio. The HRCS system released an additional 20–30% of cooling output, and it could adapt well in extreme hot and humid weather conditions compared to the AAS and the CRCS system. The overall cooling impact ratio of the HRCS with an airbox convector was approximately 185% higher than that of the AAS and 8.5% higher than that of the CRCS. This study can provide the design references for the hybrid radiant cooling system and other cooling systems in hot and humid summer conditions.

Modelling of underlying social psychological effects on occupant energy-related behaviours

Occupant energy-related behaviour research practices based on objective factors may not provide helpful insights that can derive from social sciences perspectives. This study examined how motivation (i.e., attitudes, personal norms), opportunity (i.e., subjective norms, organisational support, behavioural interventions, accessibility to control), and ability (i.e., perceived behavioural control, perceived and actual knowledge) explain the occupant energy-related behaviours in offices. In-person and online questionnaires were distributed across the general population of office occupants in New Zealand, and 294 valid answers were achieved. The social psychological effects on the choices of occupant energy behaviours are evaluated using a partial least squares structural equation modelling (PLS-SEM) analysis. The results showed that improving energy-saving opportunities through subjective norms, organisational support, behavioural interventions, and accessibility to control increases the occupants' perceived behavioural control and perceived knowledge to perform occupant energy-related behaviours. These opportunities and ability drivers then improve the occupants' motivation, building a strong attitude and obligation to save energy in the office environment. Understanding these social psychological factors are essential, as they utilise the development of occupant energy-related behavioural tools and integrate them with building energy performance simulations. Furthermore, the study assists in designing buildings to suit occupants’ comfort preferences and actions.

A Reference Framework for Zero Energy Districts in Panama Based on Energy Performance Simulations and Bioclimatic Design Methodology

The need for efficient buildings to contribute to sustainable development has led to the proposal of goals and regulations in different countries linked to net zero energy objectives, following approaches specific to their regions. Such regulations are not yet developed in a developing country such as Panama. Thus, this study develops the first framework for Zero Energy Districts (ZED) in Panama based on passive and active solutions through dynamic simulation. For this, an existing urbanization area consisting of 34 residential buildings, called the existing case (EC), was studied. After undergoing a design based on the bioclimatic methodology, a redesigned case (RC) is proposed to maintain thermal comfort and reduce energy consumption. Key redesign factors are the buildings’ shape, orientation, glazing, the use of shadows, material of the walls, and the air conditioning configuration. Results showed energy consumption decreases by 37.5% when considering all buildings with natural ventilation, reaching ranges of positive net energy (+356.50 kWh/m2y). In the case of nearly ZED in Panama, the ranges could be considered between 14 and 180 kWh/m2y. This balance indicates that there is potential on site to develop zero energy districts.