Comfort Simulation Research Articles

Correlation Study of Commercial Street Morphology and Pedestrian Activity in Cold Region Summers under Thermal Comfort Guidance: A Case Study of Sanlitun, Beijing

Pedestrian vitality in commercial streets is influenced by various factors, among which the spatial form of the street and the resulting thermal environment have a significant impact. This study, from the perspective of thermal comfort, combines thermal comfort simulation with pedestrian simulation to establish an optimization model based on pedestrian vitality. The model aims to analyze and quantify the impact of street spatial form on thermal comfort and pedestrian vitality, providing a comprehensive evaluation of optimization schemes for commercial street spaces. Firstly, the study identifies the levels of spatial design parameters for commercial streets and generates optimized design scenarios for commercial street spaces. Using the simulation platforms Rhino 7 Grasshopper and MATLAB R2023a, a pedestrian simulation model guided by thermal comfort is constructed and validated against empirical data. Next, the influence of commercial street spatial design parameters on store visitations is assessed, identifying the most critical design parameters. Finally, design strategies for commercial streets are proposed based on vitality-oriented layouts. The results indicate that the spatial form of the street significantly affects store visitations, with the street width-to-height ratio being the most influential factor, followed by street orientation and interface form. NW-SE-oriented streets show a 47.2% higher Total Store Visitations (TSV) value compared to E-W-oriented streets, while E-W streets exhibit a Differential Store Visitation (DSV) value 4.47 times that of NW-SE streets. Streets with a W/H ratio of 0.25 have a 54.9% higher Total Store Visitations value than those with a W/H ratio of 0.9, and streets with a W/H ratio of 0.65 exhibit a Differential Store Visitations value 1.21 times that of streets with a W/H ratio of 0.25. Considering overall street vitality, the study recommends NW-SE- and NE-SW-oriented streets, with a width-to-height ratio between 0.25 and 0.4. The study also proposes strategies for the modification and expansion of streets in different orientations, providing the scientific basis and optimization recommendations for the planning and renovation of commercial streets in cold regions during summer.

Thermal Comfort Simulation in Furniture Design: Integrating Considerations of the Building Thermal Environment

Thermal Comfort Simulation in Furniture Design: Integrating Considerations of the Building Thermal Environment

Research on Kindergarten Architectural Layout in Hot and Humid Regions Based on Outdoor Thermal Comfort Simulation

Sufficient outdoor activities are beneficial for the comprehensive development of young children. The high summer temperatures and humidity in hot and humid regions pose a challenge to outdoor comfort. Creating comfortable outdoor spaces for activities is particularly important.This study takes Guangzhou City as an example and summarizes the typical layout forms of kindergarten buildings. The Universal Thermal Climate Index is used as an evaluation metric. Simulation analyses of outdoor thermal comfort are conducted using the Grasshopper platform and Ladybug Tools plugin. The study categorically discusses thermal comfort in different layout forms and establishes single variable factors to further explore the extent to which different design elements affect outdoor thermal comfort. It explores design strategies to enhance outdoor thermal comfort in various layout forms, aiming to provide reliable data and references for the design of kindergarten architectural layouts in hot and humid regions.

A satellite-based approach for thermal comfort simulation: A case study in the GBA

With global warming, the issue of urban surface overheating has emerged as one of the most urgent concerns for modern cities worldwide. However, the simulation of thermal comfort with high spatiotemporal resolution remains a challenge. In this study, an approach is presented to integrate several global meteorological raster data for the production of high spatial and temporal resolution thermal comfort raster datasets. Our approach produced a dataset in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) covering 98.30% of diurnal moments in 5 years, and the spatial coverage of the region exceeded 87%. The assessment results showed that from 2002 to 2020, mean universal thermal climate index (UTCI) slightly increases from 16.0 to 20.6 °C to 17.3–26.2 °C, dominated by no heat stress (9.0 °C–26.0 °C). The low-value center of UTCI locates in the north GBA, around Zhaoqing and northern Guangzhou, while the high-value center moved westward from Huizhou to Foshan, Dongguan, and the south of Guangzhou. Over the past 18 years, the heat stress has become larger in the spatial extent and more prolonged. The heat island effect has intensified over the past 18 years, resulting in a coexistence of the positive heat island intensity and the negative heat island intensity. The result investigates urban thermal comfort conditions for urban thermal environment management and provides a spatial reference for human-centered urban planning.

The Financial Impact Potential as A Consequence of Thermal Discomfort in a Low-income Living Space: The Case Study of Rusunawa Pengadegan, Jakarta

The cost of electricity incurred for providing a thermally comfortable living space in big cities like Jakarta, by using fans and air conditioners, takes up to 32,41% of the overall utility cost per low-income household. The use of air conditioners by the low-income residents of a number of rusunawas in Jakarta, however, is clearly observable from the outside. This condition not only emphasizes the importance of a thermally comfortable living space but also the impact of the architects’ decisions in designing affordable vertical housings on the economy of the occupants. The aim of this study is to find the impact of the architect’s design decisions as reflected in the building shape and orientation as well as the opening dimensions on the thermal comfort as experienced by the residents and how it further affects their economy. This study uses rusunawa Pengadegan in South Jakarta as its research location. The study was conducted by developing a thermal comfort simulation and an observation on the evidence of use of air conditioners followed with a predictive calculation on the affected electricity cost. The aim is to examine the suitability of the rusunawa design toward the economic livelihood of the residents in the long run.

Identifying Façade Orientations with Closely Similar Thermal Performance for Unifying Façade Design Features in Hot Arid Climate

Large-scale residential projects require architects to balance energy efficiency, thermal comfort, and cost-effectiveness in designing building units distributed in different orientations. Applying a single design to all orientations may not result in comfort conditions and energy efficiency; meanwhile, creating a unique design solution for each orientation can be time-consuming and costly to implement. Despite numerous studies recommending design alternatives for particular orientations, the ranges where orientation changes do not demand a change in the façade design still need to be determined. This research aims to identify ranges for which changes in building orientation do not necessitate changes in the façade design. It involves conducting parametric energy and thermal comfort simulations in a test room and testing the findings using real-life datasets from a large-scale residential project. Glass type, window-to-wall ratio (WWR), and utilization of shading devices were among the design parameters investigated. Results show that for all-year-round occupancy projects, a common solution can be applied for orientation changes between 0° to 10° from the north, −10° from the south, and ±5° from east and west for WWR of less than 50% in hot arid climates. These ranges can increase for small WWRs and when reflective glazing or shading devices are applied. This helps streamline design and construction processes, lower costs, and save energy in large-scale residential projects.

Establishing a link between complex courtyard spaces and thermal comfort: A major advancement in evidence-based design

Amidst climate change, the importance of climate-adaptive design in architecture and landscape design has surged, particularly in residential courtyards, where optimizing the microclimate is paramount to residents' well-being. Traditional spatial indices, however, fall short in accurately characterizing complex courtyards and local spatial features. To overcome these limitations, this study introduces pixel-level spatial indicators that effectively overcome these constraints. These indicators are implemented using computational geometry algorithms such as Ray Tracing, Flood Fill, and A*, enabling simulation of various courtyard spatial indicator maps. We also utilize Graphics Processing Unit (GPU)-based rapid thermal comfort simulation technology to generate thermal comfort maps. By applying data mining methods such as Partial Least Squares Regression (PLSR), Pearson correlation, and Nearest-neighbor interpolation, we explore the relationships between spatial indicators and thermal comfort, ultimately identifying key indicators and determining the guiding thresholds and influencing trends corresponding to heat discomfort frequency. Six key indicators and th emerge: Building View Factor (BVF), indicating building coverage visibility (prefer above 0.11); Solar Beam Fraction (BEAM), illustrating Summer solstice sun shading condition (prefer below 0.78); Averaged View Factor (AVF), showing overall visibility (prefer below 0.40); Directional Sky View Factor (DSVF(W)), reflecting sky visibility in a specific orientation (prefer below 0.73); Tree View Factor (TVF), denoting tree coverage visibility (prefer above 0.18); and Plan Water Ratio (PWR), signifying water surface proportion (aim for below 0.44). These insights, integrated into design tools, contribute to evidence-based microclimate regulation strategies, thereby enhancing urban residents' thermal comfort and overall well-being.

Influence of landscape interventions on thermal comfort under time-varying building shadow; new Gwanghwamun square case, Seoul, South Korea

This study investigated the cooling effects of landscape interventions and their relative magnitude under hybrid urban context including time-varying building shadow cast. The study focused on the practical design alternatives, rather than experimental scenarios. We conducted outdoor thermal comfort (OTC) simulation using ENVI-met, and spatial-temporal comparison analysis for three green space expansion interventions for new Gwanghwamun square, Seoul, South Korea. In addition, we statistically analyzed the relationship between TCR (tree coverage ratio), GCR (green coverage ratio), WCR (water coverage ratio) and PET (Physiological Equivalent Temperature). The correlation and regression coefficients of the relationships under different building density, building locations and shadow cast conditions were compared. As a result of three interventions comparison, the comfort zone increased almost two times, while the discomfort zone decreased to ≈70% of the current condition in the long-term alternative. As TCR increases 22%, PET decreases up to 2.6 °C in average. Tree coverage ratio showed significant importance among the landscape elements. The influence of trees was slightly different for different contexts; larger cooling effect was found in no building shadow cast and low-density buildings. However, the difference was not noticeable; the influence of trees is still effective under building shadow cast and high-density buildings. Moreover, for high tree density area (TCR>50%), temporal gap of thermal comfort between measured time that mainly caused by building shadow change was greatly reduced compared to low tree density area (TCR<5%), which suggest the important role of tree in providing consistent thermal comfort. This study provides scientific evidence for trees’ cooling effect and its relative magnitude under diverse built contexts of N–S oriented urban canyon. This study also contributes to developing an inclusive thermal comfort evaluation method based on both temporal and spatial scales for the effective comparison of real-world design alternatives.

Regression Models and Shape Descriptors for Building Energy Demand and Comfort Estimation

Optimal building design in terms of comfort and energy performance means designing and constructing a building that requires the minimum energy demand under the given conditions while also providing a good level of human comfort. This paper focuses on replacing the complex energy and comfort simulation procedure with fast regression model-based processes that encounter the building shape as input. Numerous building shape descriptors were applied as inputs to several regression models. After evaluating the results, it can be stated that, with careful selection of building geometry describing design input variables, complex energy and comfort simulations can be approximated. Six different models with five different building shape descriptors were tested. The worst results were around R2 = 0.75, and the generic results were around R2 = 0.92. The most accurate prediction models, with the highest level of accuracy (R2 &gt; 0.97), were linear regressions using 3rd power and dense neural networks using 1st power of inputs; furthermore, averages of mean absolute percentage errors are 1% in the case of dense neural networks. For the best performance, the building configuration was described by a discrete functional point cloud. The proposed method can effectively aid future building energy and comfort optimization processes.

A novel outdoor thermal comfort simulation model for heritage environments (OTC-SM-HE): Verify the effectiveness in Gulangyu, China

The study of outdoor thermal comfort (OTC) for heritage environments can offer essential guidance for the articulation of multiple values of cultural heritage and the sustainable development of traditional settlements. However, previous study methods often fail to capture the complexity and diversity of heritage environments completely. This study proposes a novel outdoor thermal comfort simulation model for heritage environments (OTC-SM-HE) based on 3D real scene modeling technology and universal thermal climate index (UTCI). The effectiveness of the model is verified by comparing it with field test data in Gulangyu Island. The results show that: 1) UTCI are calculated by OTC-SM-HE and field testing showed high proximity started at 14:00 or 15:00 in the same space on different dates, respectively. 2) The mean error is 2.02 °C of UTCI in the same period and space, and the mean d-index of validation of models is 0.735.3) The similarity of trend duration is 85% in field test time. Thus, OTC-SM-HE can be shown to be effective in terms of response spatial characteristics, numerical values and variation trends. The establishment of OTC-SM-HE aims to simulate and evaluate the effects of meteorological conditions, shading facilities, and greening measures on the OTC of visitors and residents in different heritage environments. It provides a scientific basis and optimization recommendations for the sustainable management of heritage environments.

Developing a three-dimensional urban surface model for spatiotemporal analysis of thermal comfort with respect to street direction

Understanding the urban heat problem, which is intensifying owing to urbanization and climate change, has become a great challenge. Evaluating the thermal environment of urban spaces and predicting changes based on urban planning are essential for developing optimal urban cooling plans. This study addresses the pressing challenge of urban heat by developing a three-dimensional urban surface model (3D-USM) and conducting spatiotemporal thermal comfort simulations, providing valuable insights for the development of effective urban cooling strategies in the face of urbanization and climate change. Mean radiant temperature (MRT), the key element of thermal comfort of humans by reflecting complex urban environments was simulated in east-west streets which are vulnerable to heat, and results demonstrate that a small change of street angle has a significant effect on pedestrian thermal comfort. Specifically, at 0900 LST, the southern sidewalk of the street rotated by 12.5° was more vulnerable than the northern sidewalk. This resulted in a shift in the optimal location of trees that provide effective cooling, highlighting the importance of considering street orientation in the placement of urban greenery. This suggests that spatiotemporal thermal comfort simulations considering urban form in detail are necessary to efficiently cool the city. The proposed 3D-USM, capable of accurately and efficiently simulating the thermal environment and MRT thermal comfort in complex urban environments using simple input data, holds great potential for guiding the development of efficient cooling strategies to foster sustainable cities.

Modelling and experimental characterization of secondary suspension elements for rail vehicle ride comfort simulation

Secondary suspensions play an essential role in the dynamic behaviour of rail vehicles. In particular, they are adopted to reduce the vibrations transmitted to the carbody, thus improving ride comfort. In this paper, an experimental characterization of the viscous damper and coil spring elements composing a vertical secondary suspension is presented. The elements are separately tested with the aim of analysing their dynamic behaviour. Then, modified prototypes are manufactured to reduce the transmitted force. The results of the experimental campaign are later adopted to tune the parameters of the mathematical model of the whole secondary suspension, including the dynamics of both the coil spring and the damper elements. This model allows discussing the effectiveness of the proposed modifications, proving the design of both the components to be fundamental for the improvement of ride comfort.

Towards Achieving Sustainable Development Goal-2030 Agenda-Thirteen: A Review of Technological Advances from the Built Environment Professionals

Natural resources are increasingly under pressures to cater for the growing human population and their corresponding, often conflicting needs. However, the need to conservatively utilize these resources without deteriorating the environment to the disadvantage of the future generations has prompted some actionable steps at the global level, the prominent of which is the promulgation of the United Nation’s Sustainable Development Goal 2030 (SDG-2030) Agenda, having seventeen (17) inter-related actionable areas of human endeavours (i.e., Agenda). Of particular interest within this context is the Agenda Thirteen (Agenda-13) which encompasses the need for urgent action to combat Climate Change and its impacts across various areas of human engagements. This is necessary as Climate Change impacts are characterized with anthropogenic carbon emissions resulting in global temperature rise, sea level rise, flooding, desertification, droughts, and other related disasters. Within the precinct of Built Environment, it is established that building construction and operation alone account for about 40% of the global emissions. This calls for concerns and requires urgent collaborative actions to curtail the trend. This submission, which is review based therefore, highlights various joint efforts particularly, integration of technological advancements by the relevant building professionals, towards attaining the goal of Agenda-13. This is with a view to limiting climate change enablers for reduced environmental impacts. These collaborative efforts are categorized into pre-construction and post-construction activities from the relevant professionals in the built environment. While the former includes Indoor Thermal Comfort Simulation, Integration of Daylighting Technologies, and adoption of Computational Fluid Dynamics integrated architectural design process, the latter consists of design of Double Skin Facades, development of Building Integrated Photovoltaics façade, integration of Evacuated Tube Solar Air Collector System, adoption of Phase Change Material on Building façade, and implementation of Life Cycle Energy Analysis Policy, among others. These endeavours aim at reducing carbon emissions at the building micro level for overall clean, safe and sustainable global environment.

Performance evaluation of a single-side windcatcher in the transitional seasons (case study: Khousf town, Southern Khorasan Province, Iran)

PurposeLife experience in hot and arid areas of Iran has proved that in the transitional seasons (spring and autumn) in which the climate is not too hot, passive cooling systems such as windcatchers (baadgir) have functioned well. This paper intends to investigate the efficiency of a single-side windcatcher as a passive cooling strategy; the case study is the Bina House windcatcher, located in Khousf town, near Birjand city, Iran.Design/methodology/approachTo achieve the aim, air temperature, relative humidity, wind data and mean radiant temperature were measured by the related tools over five days from September 23 to October 23. Then, the thermal performance of the windcatcher was examined by analyzing the effects of all these factors on human thermal comfort. Quantitative assessment of the indoor environment was estimated using DesignBuilder and its computational fluid dynamics (CFD) tool, a thermal comfort simulation method to compare the cooling potential of the windcatcher. Windcatcher performance was then compared with two other common cooling systems in the area: single-side window, and evaporative cooler.FindingsThe results showed that both windcatcher and evaporative cooler can provide thermal comfort for Khousf residents in the transitional seasons; but the difference is that an evaporative cooler needs to consume water and electricity power, while a windcatcher is a passive cooling system that uses clean energy of wind.Originality/valueThe present study, by quantitative study of single-side windcatchers in a desert region, measured the climatic factors of a historical house and compared it with thermal comfort criteria. Therefore, the results of field measurements were analyzed, and the efficiency of the windcatcher was compared with two other cooling systems, namely single-side ventilation and evaporative cooler, in the two seasons of summer and autumn (transition seasons).

A MIMO system for the replication of accelerations excited in a vehicle by single obstacle crossings at comfort-relevant excitation points in a comfort simulator

This paper presents the replication of accelerations in a vehicle excited from single obstacle crossings. The accelerations should be replicated at multiple comfort-relevant excitation points in a comfort-simulator. For the vertical accelerations at the seat rails and the foot rests, research on the positions and the number of shakers is conducted. The implementation of an electrodynamic shaker for each controlled measurement point turns out to be mandatory. By positioning them at the left and right seat rails, errors can be minimized due to similarities in the transmission behavior. The longitudinal excitations of the seat back by means of shakers are performed very precisely. The direct coupling by a construction on the headrest allows fast exchange of the vehicle seats. The combination of all acceleration replications simultaneously can be performed satisfactorily comparing them with in-vehicle field measurements. The noise-based excitation signal for system identification turns out to be a significant parameter.

Development of Virtual Human Agents with Different Thermal Preferences for Energy and Thermal Comfort Simulation

Researchers have used building energy simulation tools such as EnergyPlus to evaluate building energy and occupant thermal preference. EnergyPlus is a powerful tool for modeling buildings, However, when controlling the indoor set temperature using EnergyPlus, it is common to assume that all occupants’ thermal preference is same. Therefore, it is difficult to know dynamic personal thermal preferences and to implement occupant centric set-point control. In this study, we propose the various human agents with different thermal preference to realize the reliability of the simulation. First, we make an agent generation algorithm by referring the characteristics of various existing individual thermal preference models. And then, create agents with a virtual thermal preference to suit our needs. Through that, it is expected to allow human agents to feel different preference in one space during simulation. The final significance of the study is to contribute to the evaluation of building energy and thermal comfort closer to reality through the agent created in this method.

Acceleration signal simulation induced by single obstacle crossings by means of nonlinear, block-oriented models for an automotive comfort simulator

This paper presents a method for replicating transient signals induced in a passenger car by single-obstacle crossings. These replicated signals should be used in a ride comfort simulator. By using feedforward-inverse-model-control with direct identification of the inverse transfer function, time-consuming iterations of conventional time waveform replication methods are eliminated. The quality of the system identification for approximating the inverse transfer function is significantly increased by decomposing the frequency band and the complexity is considerably reduced. The use of nonlinear block-oriented models significantly decreases the replication errors in frequency bands with high nonlinearity influence.

Validation of a ride comfort simulation strategy on an electric Stewart Platform for real road driving applications

In this paper, the validation of the comfort simulation strategy on an electric Stewart Platform under road driving scenarios is explained. First, an introduction to the vibroacoustic comfort theory in passenger cars is presented. Second, the Stewart Platform used for the validation process is explained. Third, the methodology conducted for the validation of a hexapod for ride comfort applications is detailed. Finally, the Stewart Platform has been validated under real world road driving scenarios for the 6 degrees-of-freedom by means of the Vibration Dose Value. The final goal of the validation strategy of the electric Stewart Platform is to perform ride and comfort studies in a driving simulator for the 1–10 Hz frequency range.

On Pre-Emptive In-Wheel Motor Control for Reducing the Longitudinal Acceleration Oscillations Caused by Road Irregularities

Road irregularities induce vertical and longitudinal vibrations of the sprung and unsprung masses, which affect vehicle comfort. While the vertical dynamics and related compensation techniques are extensively covered by the suspension control literature, the longitudinal dynamics on uneven road surfaces are less frequently addressed, and are significantly influenced by the tires and suspension systems. The relatively slow response of internal combustion engines does not allow any form of active compensation of the effect of road irregularities. However, in-wheel electric powertrains, in conjunction with pre-emptive control based on the information on the road profile ahead, have some potential for effective compensation, which, however, has not been explored yet. This paper presents a proof-of-concept nonlinear model predictive control (NMPC) implementation based on road preview, which is preliminarily assessed with a simulation model of an all-wheel drive electric vehicle with in-wheel motors, including a realistic tire model for ride comfort simulation. The major improvement brought by the proposed road preview controller is evaluated through objective performance indicators along multiple maneuvers, and is confirmed by the comparison with two benchmarking feedback controllers from the literature.

Assessment of the overall energy performance of an SPD smart window in a hot desert climate

In this study, the overall energy consumption and visual comfort of a switchable suspended particle device (SPD) smart window were investigated as part of the glazing integration of an adaptive building designed to consume less energy in a hot desert climate. A typical floor of a commercial office building in Riyadh was chosen for the energy and visual comfort simulation, which was based on Energy-Plus and Diva-for-Rhino software for cardinal orientation. A comprehensive simulation analysis of various state of SPD glazing, namely opaque (OFF), transparent (ON) and automated controlled (based on solar radiance: from 100w/m2 – 900w/m2), was conducted and the results were compared against traditional single glazing and double-glazing low emissivity (DG low-e) coated windows for reference. The simulation results indicated that switchable SPD smart windows (in the OFF and automated states) achieved a promising reduction of net energy by up to 58% against DG low-e, apart from at the northern orientation. Conversely, the opaque (OFF state) had a counterproductive impact on lighting energy consumption and visual comfort. Acceptable daylight autonomy (DA300lux) and Useful daylight illuminance (UDI100lux–2000lux) was observed for the SPD smart window in the ON and automated controlled states; moreover, it offered a significant reduction in daylight glare probability (DGP). Thus, controlled switchable SPD glazing can be a good alternative to standard glazing in a hot desert climate in terms of reducing energy use and providing visual comfort.