Indoor Thermal Comfort Research Articles

Energy consumption and thermal comfort of rock-cut and modern buildings

Energy consumption in the building sector justifies the necessity of knowing the thermal comfort perception of vernacular and modern architectural types, based on which a correct recognition was reached for the design of buildings suitable for the climatic conditions of each region. It should be determined that the different types of modern and traditional architecture are in the comfort level in harsh hot climate conditions and how much energy they consume to reach the comfort level. Despite consideration of energy consumption and thermal comfort in different buildings in Iran, there is no clear framework for evaluating these two parameters in different buildings and comparing them. This research aims to compare the indoor thermal comfort levels of vernacular architectural buildings and modern buildings in Iran's semi-hot and dry climate at the peak of summer heat and determine their energy consumption to reach the comfort level. This study has been accomplished by collecting field data, examining the indoor predicted mean vote (PMV) index of the buildings, and comparing them. It was found that rock-cut architecture buildings are in better thermal comfort conditions without energy consumption due to the use of groundmass temperature and low heat exchanges between the indoors and outdoors because of the thermal phase of the materials and the thickness of its layers. The indoor PMV average of rock-cut buildings in summer is −0.61; in modern buildings, it is 0.77, while these two building complexes are in the same climate and close. Also, the energy consumption to reach the comfort level in rock-cut buildings is zero, while modern buildings consume an average of 7.7 kW of electricity daily. The research results will lead to recognizing and modeling the climate design of vernacular architecture, which can be used in today's architecture to reduce energy consumption.

On-site evaluation of indoor thermal comfort and energy performance of a liquid-desiccant assisted air-conditioning system in a high-latent-load building

Indoor humidity control is increasingly important because indoor sensible heat ratio decreases to reduce building energy consumption. However, reference vapor compression cooling systems exhibit energy inefficiency and limitations in maintaining indoor thermal comfort. Therefore, this study proposes an alternative heat-pump-driven liquid-desiccant air-conditioning system, independently controlling air temperature and humidity. The reference and proposed systems are applied to a high-latent-load building to investigate their onsite indoor thermal comfort and energy performance empirically and simultaneously under various outdoor summer conditions. The reference system exhibits a thermal comfort satisfaction ratio of 97% only under limited hot and dry weather. Conversely, the thermal comfort satisfaction ratio sharply drops to 2% or less under humid weather. The proposed system consistently achieves a high thermal comfort satisfaction ratio exceeding 90% under various outdoor summer conditions. In empirical comparisons, the proposed system can maintain a thermally comfortable room for an hour while achieving energy savings exceeding 92.4% and 12.1% under warm and humid (rainy season) and hot and humid outdoor conditions, respectively. The proposed system is concluded to consistently maintain indoor thermal comfort while using energy efficiently, demonstrating its widespread applicability for general high-latent-load buildings characterized by low indoor sensible heat ratio values of 0.56 on average.

Cooling collars incorporated with PCM packs and gels to improve indoor thermal comfort in healthy young females

The human neck is one of the most thermally sensitive body regions to nociceptive stimuli. Neck cooling has been extensively researched to improve athletic performance in the heat. However, there has been very little research into the use of conductive neck cooling for indoor thermal comfort. We thereby designed three ultralight cooling collars with cooling gels or phase change materials (GEL6, PCM15, and PCM18). Their cooling performance on thermal comfort enhancement of 14 healthy young female participants under two warm indoor temperatures (28 °C and 30 °C) was investigated. Thermophysiological and perceptual responses, including skin temperature, heart rate, sweating, thermal sensation vote (TSV), thermal comfort vote (TCV), and thermal preference vote (TPV), were extensively studied. Results showed that, in contrast to GEL6, PCM15 and PCM18 significantly decreased the neck skin temperature, with PCM15 exhibiting the greatest reduction of 4.37 °C at 28 °C. PCM15 and PCM18 significantly decreased overall and local TSVs while also increasing overall and local TCVs (all p < 0.05), thus they could maintain >80 % occupant satisfaction at 28 °C. At 30 °C indoor temperature, however, none of these three cooling collars were found to meet the 80 % occupant satisfaction criterion. When compared to GEL6, PCM15 and PCM18 were found to only significantly reduce local TSVs at the head and neck (all p < 0.05). In sum, PCM15 and PCM18 have the potential to increase acceptable HVAC summer cooling setpoint temperature by 2.5 °C, from 25.5 °C to 28.0 °C, leading to a 25 % reduction in building cooling energy consumption.

Optimizing the indoor thermal environment and daylight performance of buildings with PCM glazing

With the development of energy efficient technologies for glass envelopes, using thermal storage techniques to improve their thermal inertia has become a trend in research. In the present study, the heat transfer and day-lighting models of a building with PCM glazing curtain wall (PGC) were developed. Multiple parameters such as glazing internal surface temperature, PCM liquid phase rate, indoor temperature, natural illumination, and daylighting coefficient were quantitatively analyzed to evaluate their indoor thermal environment and daylighting performance. The results show that the application of PGC can significantly improve indoor temperature uniformity and indoor thermal comfort compared to silica aerogel glass curtain wall (SGC) and hollow glass curtain wall (HGC). By filling 10 mm thick PCM, the temperature fluctuation of the inner surface of the glass and the midpoint temperature of the room can be reduced by 35 %, the peak temperature of the inner surface of the glass can be delayed by 0.89 h, and the average indoor natural light value and indoor daylight factor are satisfactory at 453.26 lx and 9.63 %, respectively. However, as the thickness of the PCM increases to 15 and 20 mm, the liquid fraction of the PCM and the energy storage performance of the PGC are greatly reduced, and natural daylighting does not meet the GB/t-50033-2013 limit.

The Annual Effect of Landscapes on the Indoor Thermal Environment in Residential Areas—A Case Study in Southern Hunan

Landscape elements are crucial to the quality of the built environment. Thermal comfort is one of the important paths through which landscape elements affect the quality of the built environment. Most studies investigate the impacts of the landscape on the outdoor thermal environment, while ignoring the impacts on the indoor environment. A residential area in Chenzhou, a typical city having a hot summer and cold winter climate, was taken as an example to reveal the effect on the indoor thermal environment of landscapes. The annual distribution of the indoor thermal environment was analyzed with the “Envi-met+IDW” model, which was created to evaluate the annual thermal impact. Analytical results show that, from the perspective of the annual cycle, the camphor tree has the best performance in regulating the indoor thermal environment, followed by water and the palm. Manila grass has a very weak impact on indoor thermal comfort throughout the year. Camphor trees, water, and palm extend the “acceptable temperature” by 523 h, 416 h, and 388 h respectively. However, the camphor tree also has the strongest cooling effect on indoor environments during winter, increasing the “heating demand temperature” by 289 h.

Geometrical optimization of solar venetian blinds in residential buildings to improve the economic costs of the building and the visual comfort of the residents using the NSGA-II algorithm

The entering sunlight from the building's windows mainly affects the heating and visual comfort of the occupants. The applications of Venetian blinds are a solution to improve the heating and visual comfort of the occupants. However, reducing the sunlight that enters the space can result in a rise in the building's electricity consumption. While most studies focus on the electricity production of solar panels, present study aims to examine the effect of solar venetian blinds on the indoor visual and thermal comfort of the occupants and optimize their geometry considering different geographical specifications. In the present paper, efforts are made to numerically install solar panels on Venetian blinds and analyze the effect of changing the geometrical parameters of solar Venetian blinds and the building's window dimensions on visual comfort and net electricity. Therefore, the target functions in the present paper are an improvement percentage in the daylight glare index and an improvement percentage in the net electricity costs for the analyzed building. As a result, five cities in Iran that have different climatic conditions are targeted to model the building. EnergyPlus software is employed to conduct the energy-based calculations, and the design variables and target functions are defined using JEPLUS software. The outputs are next inserted in JEPLUS+EA software to process a multi-objective optimization using the NSGA-II algorithm. The results demonstrate that the visual comfort and net electricity can be optimized by ranges of 10–100% and 1.5–10%, respectively. Furthermore, Venetian blinds are proven to have higher reception of sun radiations and better efficiency in southern cities and they can have a more proper performance while being installed for windows of southern building wall.

Thermal conditions and daylight availability in different zones of courtyard buildings; a study in Iran

ABSTRACT Passive design strategies enhance indoor thermal comfort and reduce energy consumption in buildings located in hot climates. Thus, exploring the various zones of a house’s yard can yield valuable insights for devising a plan that achieves high energy and lighting efficiency. This study examines the climate-responsive design strategies of 20 traditional courtyard buildings in Birjand’s hot and dry climate. These courtyard houses informed modelling a new hypothetical house in DesignBuilder. Two main orientations (45° = NE–SW, and 315° = NW–SE) were used for comparing their impact on indoor air temperature, solar gain and daylight factor across various courtyard zones. The findings indicate that during winter, the interiors of courtyard houses maintain a temperature higher than the exterior, while in summer, they remain cooler than outside conditions. Concerning the influence of orientation on indoor climates, the NE–SW orientation yielded the greatest solar gains for windows in the northern and western zones. Conversely, in the NW–SE orientation, the most substantial solar gains were recorded for windows in the northern and eastern zones. Additionally, the study noted a marginal variation in the daylight factor across different zones of the courtyard houses when comparing the two orientations.

Research on the effect of exercise behavior on thermal comfort and heating degree days in sports buildings

The exercise behavior has a significant impact on thermal comfort and energy consumption in heating buildings. It is crucial to strike a balance between building energy efficiency and indoor thermal comfort. In this study, we assessed thermal comfort during exercise under indoor conditions in winter by testing the exercise routine of 60 subjects and calculating the number of heating degree days and optimizing the heating cycle. The results showed that exercise behavior significantly affects thermal comfort, with the thermal sensory zone corresponding to thermal comfort shifting and expanding towards the neutral and cooler side. The actual thermal comfort range of the subjects expanded (14.5–17.1 °C) compared to the thermal comfort criterion, suggesting that exercise behavior enhanced the subjects' adaptive capacity. Specifically, at temperatures below thermal neutral (15.8 °C), subjects exhibited a high level of environmental satisfaction, reaching at least 80 %. Additionally, subjects demonstrated thermal 'superconductivity,' with preferred and comfort temperatures approximately 0.8 °C and 0.5 °C lower than the thermal neutral temperature, respectively, indicating a preference for neutral or slightly cooler environments in winter. Furthermore, the base temperature (15.7 °C) was 2.3 °C lower, indicating that heating degree days 18 significantly overestimated heating demand by a factor of at least 1.4. The upper and lower indoor heating set point temperatures (15–17 °C) are about 1–7 °C and 1–3 °C lower than the Chinese building energy efficiency standards, respectively, demonstrating superior energy efficiency in the context of exercise behavior.

Quantification of the interactions between indoor environmental conditions and human thermal comfort and susceptibility in tropical coastal environments

The indoor environment in most of the tropical coastal regions is associated with the residents’ health and well-being. However, limited studies reported on quantifying the interrelation between indoor environmental quality, thermal comfort and residents’ health risks in such climatic regions. Here, we evaluate indoor thermal comfort in coastal eastern India that falls under the ‘ Tropical Savanna’ climatic region. The perception survey was conducted to collect primary data in summer, monsoon, post-monsoon and winter across the year and the perception of warmth appeared to have a similar trend to direct and rational human thermal indices derived from a composite body heat exchange. Results indicate that indoor thermal stress significantly differed ( p &lt; .05) between seasons and across study locations. The maximum summer and monsoon days lay in a warm to very hot zone. Additionally, most of the heat-related stress or disorders significantly differed ( p &lt; .01) amongst different age groups of people. Finally, a principal component analysis using the human thermal indices yielded three groups of heat-related symptoms (a) physical fatigue and responses, (b) neural stressors and (c) hyperhidrosis disorder. Overall, results suggested that physical fatigue and responses arose predominantly from climate-induced thermal stress. The study recommends an effective bioclimatic design strategy following human-environment friendliness that can improve indoor thermal comfort in coastal eastern India.

Real-time spatial-temporal mapping and visualization of thermal comfort and HVAC control by integrating immersive augmented reality technologies and IoT-enabled wireless sensor networks: Towards immersive human-building interactions

Existing methods to assess and visualize thermal comfort mainly focused on either individual users (e.g., through wearables) or for specific locations where sensors are installed, rather than continuously for the entire indoor space. Also, most of the existing thermal comfort visualization methods and HVAC system control approaches rely on phones and mobile devices and lack a fully immersive/interactive experience and human-building interaction. Thus, this paper develops an immersive human-building interaction framework for real-time spatial-temporal mapping and visualization of indoor thermal comfort by integrating immersive augmented reality (AR) technologies and IoT-enabled smart wireless sensor networks (WSNs) (i.e., temperature and relative humidity data) to provide thermal comfort assessment for the entire space (rather than at localized/individual locations/points) and to enable users to interact with and adjust the HVAC systems from a distance using fully immersive and realistic environments. First, a smart WSN comprised of four IoT-enabled sensing stations was developed to collect real-time thermal comfort-related information (i.e., temperature and relative humidity). Second, an AR environment was created using the Unity engine, where virtual objects were overlayed into, and aligned with, the real-world environment. Third, the real-time data from the IoT-enabled WSN was integrated into the AR environment using various programming scripts that add multiple functionalities to the users, including controlling the HVAC system and visualizing the thermal comfort along the entire indoor space or room of interest through a spatial-temporal map. Fourth, the developed framework was validated and evaluated by 118 participants using a survey questionnaire. The findings showed that the graphical satisfaction achieved an overall average score of 4.75 out of 5, the user's sense of spatial presence was rated at an average score of 4.68 out of 5, the involvement aspects of the developed approach received an overall average score of 4.80 out of 5, and experienced realism was rated at an average score of 4.58 out of 5. Ultimately, this paper contributes to enhanced and intelligent human-building interaction and visualization through the use of emerging technologies by allowing the building users to control and interact with the HVAC systems using AR capabilities to improve the health and well-being of the building occupants.

Advancing sustainable construction through innovative transparent wood composite structures with enhanced functionalities

Advancements in transparent wood materials hold immense promise for eco-friendly construction, combating resource depletion, and enhancing energy efficiency. Yet, the quest for versatility and global uniformity poses challenges. Enter our breakthrough: a three-layer transparent wood that integrates thermal energy storage. We achieved this by compressing three partially impregnated wood substrates, featuring a silica-stabilized polyethylene glycol (PEG) core flanked by two polymethyl methacrylate (PMMA) layers. In pursuit of optical and mechanical perfection, we employed a multi-layer approach to ensure global isotropy. Morphological analysis unveiled compact, hierarchical structures in the core, PEG encapsulation, and an innovative solution for preventing leaks, culminating in a remarkable latent heat of 15.0 J/g and superior thermal stability. Optical testing reported outstanding properties, with an optical transmittance of 45 % and a haze of 76 % at 800 nm. Our design featuring crossed-lamination not only achieved isotropic light distribution but also improved mechanical consistency and water resistance. Notably, our environmentally-simulated tests showcased remarkable thermal insulation properties, credited to a low thermal conductivity (0.34 W/mK) surpassing traditional glass, as well as phase-change functionality. Our pioneering multilayer transparent wood stands to revolutionize energy-efficient construction and elevate indoor thermal comfort.

Moderating AC Usage Can Reduce Thermal Disparity between Indoor and Outdoor Environments.

In the context of escalating urban heat events due to climate change, air conditioning (AC) has become a critical factor in maintaining indoor thermal comfort. Yet the usage of AC can also exacerbate outdoor heat stress and burden the electricity system, and there is little scientific knowledge regarding how to balance these conflicting goals. To address this issue, we established a coupled modeling approach, integrating the Weather Research and Forecasting model with the building energy model (WRF_BEP + BEM), and designed multiple AC usage scenarios. We selected Chongqing, China's fourth-largest megacity, as our study area due to its significant socioeconomic importance, the severity of extreme heat events, and the uniqueness of its energy infrastructure. Our analysis reveals that AC systems can substantially reduce indoor temperatures by up to 18 °C; however, it also identifies substantial nighttime warming (2-2.5 °C) and a decline in thermal comfort. Particularly for high-density neighborhoods, when we increase 2 °C indoors, the outdoor temperature can be alleviated by up to 1 °C. Besides, despite the limited capacity to regulate peak electricity demand, we identified that reducing the spatial cooled fraction, increasing targeted indoor temperature by 2 °C, and implementing temporal AC schedules can effectively lower energy consumption in high-density neighborhoods, especially the reduction of spatial cooled fraction (up to 50%). Considering the substantial demand for cooling energy, it is imperative to carefully assess the adequacy and continuity of backup energy sources. The study underscores the urgency of reassessing energy resilience and advocates for addressing the thermal equity between indoor and outdoor environments, contributing to the development of a sustainable and just urban climate strategy in an era of intensifying heat events.

Modeling indoor thermal comfort in buildings using digital twin and machine learning

Digital Twin (DT) concept is used in different domains and industries, including the building industry, as it has physical and digital assets with the help of Building Information Modeling (BIM). Technologies and methodologies constantly enrich the building industry because the amount of data generated during different building stages is considerable and has a tremendous effect on the lifecycle of a building. Previous research underscores the importance of seamlessly exchanging information between physical and digital assets within a comprehensive framework, particularly emphasizing the integration of BIM data with various systems to enhance efficiency and prevent information loss. Despite advancements in technologies, challenges persist in optimizing methods for integrating BIM data into DT frameworks, including ensuring interoperability, scalability, and real-time monitor and control. This study addresses this research gap by proposing a comprehensive platform that integrates the DT concept with IoT and BIM technologies. The platform is developed in five main stages: 1) acquiring electronic data of the building from the laser scanner, 2) developing a Wi-Fi IoT module and BIM data for physical assets and digital replica, 3) constructing the DT elements of the platform, 4) performing data analysis 5) implementing thermal comfort prediction models. Two machine learning models (Facebook prophet, NeuralProphet) are implemented to predict thermal comfort. The best predictive model is identified by evaluating its error function using historical training data collected during facility operation. A case study demonstrates the practical application of the proposed framework. The case study involves a real building where the platform is implemented to monitor and control indoor environments. By utilizing predefined data in BIM models, the platform ensures data accuracy, consistency, and usability. The case outputs reveal that Neuralprophet provides good prediction results.

Prediction models for building thermal mass of intermittently heated rooms for balancing energy consumption and indoor thermal comfort

Building thermal mass (BTM) plays an essential role in maintaining a comfortable indoor environment for intermittently heated rooms (IHR). However, how to properly determine the BTM in IHR is unclear for the comprehensive consideration of the opposite effects on the reduction of heating energy consumption (HEC) as well as the improvement of indoor thermal comfort (ITC). This study aims to investigate the comprehensive impact of BTM on the HEC and ITC of IHR in the hot summer and cold winter (HSCW) zone of China using the validated EnergyPlus model. The results indicate that BTM can significantly improve the ITC of IHR, whereas increase HEC. The degree of impact is mainly related to the internal wall heat accumulation coefficient, external wall insulation layer thermal resistance, and outdoor air mean temperature during non-heating periods. Response surface methodology is further employed to quantify the effects of BTM on HEC and ITC of IHR. Based on the predictive models, the range of parameter variations for BTM that simultaneously meet HEC and ITC requirements is obtained. The predictive models can provide a theoretical basis for balancing HEC and ITC in intermittently heated buildings in the HSCW zone of China.

Winter indoor thermal environment and livability analysis of traditional residential houses in northeast Sichuan, China

With the rapid development of the national economy, increasing attention has been given to the living environment in rural areas, especially indoor thermal and wind environments. This study conducted on-site measurements and questionnaire surveys during winter in the indoor environment of five villages in northeastern Sichuan. Eighty-nine traditional residences were selected to investigate their fundamental characteristics, indoor thermal environment, humidity conditions, and comfort levels. Questionnaires and comparative experiments were also conducted with natives and locals. This combination of objective data and subjective feedback provides a comprehensive perspective for assessing the indoor thermal environment. The results showed that when expressed as neutral temperature and humidity, the temperature difference was 2.36 °C, with little humidity difference. Residents exhibited higher tolerance towards the local thermal and humidity environment than nonlocal volunteers, who showed greater sensitivity to it. In addition, residents had a Predicted Mean Vote (PMV) value of −0.69 and a heat acceptance value of −1.78, while non-local volunteers had a PMV value of −0.76 and a heat acceptance value of −1.32. A detailed evaluation and analysis of the relationship between the indoor thermal environment and human comfort of local residential houses was carried out, providing technical guidance for energy conservation and thermal insulation of local buildings.

Spatial and Temporal Variations in Land Surface Temperature as an Indicator of Learning Comfort Level in Banten Province

Increasing population and rapid development of built-up land can cause an increase in land surface temperature. These changes are often associated with many factors, including changes in land use, and surface parameters, economic development, and vegetation. This research aims to analyze the temperature factor as an indicator of indoor thermal comfort to support the learning process in schools in the Banten Province area. This research uses a spatial temporal approach with descriptive statistical analysis. Based on the results, show that the land surface temperature at each school location in Banten province shows conditions that are not constant. The number of schools with uncomfortable conditions varies from 2019 (89.07%), 2020 (42.65%), 2021 (45.66%), 2022 (82.66%), and 2023 (52.44%). This shows that there has been a decrease in uncomfortable conditions for studying by 36.63% in the last 5 years.

Fast-Growing Bio-Based Construction Materials as an Approach to Accelerate United Nations Sustainable Development Goals

The United Nations Sustainable Development Goals (UN SDGs) ensure future human well-being. However, they face challenges due to the pressing need to reduce carbon emissions, with nearly 40% originating from the construction sector. With the current global environmental and energy crisis, there is a pressing need to address building carbon emissions and prioritise investments in passive strategies for improving indoor thermal comfort. Exploring fast-growing bio-based materials like bamboo, straw, hemp, and flax directly addresses these concerns, fostering environmental sustainability. Material selection in construction is crucial for advancing the SDGs, for example, promoting sustainable cities and communities (SDG11) and responsible consumption and production (SDG12). This paper proposes a comparative analysis of conventional and bio-based construction materials, focusing on their production stages through life cycle analysis. Tools such as Building Emissions Accounting for Materials (BEAM) and the Methodology for Relative Assessment of Sustainability (MARS) enable a detailed comparison. The results highlight the benefits of bio-based materials in storing carbon more rapidly and their lower environmental impact compared to conventional alternatives. Moreover, bio-based materials contribute to indoor moisture regulation and a healthier indoor environment, underscoring their potential to accelerate progress towards the UN SDGs through informed material choices in design practices.

Design optimization of an assisted living facility to improve summer thermal comfort in warming climates

Assisted living facilities with optimal summer thermal comfort are necessary to ensure improved quality of life for the older individuals in warming climates. Older individuals are exposed to higher mortality risks during periods of excessive heat. This study aims to identify and optimize key design variables for a passive house certified assisted living facility in Belgium with high comfort expectations using EnergyPlus to improve indoor thermal comfort during extreme climates. The sensitivity analysis used the Standard Regression Coefficient method with Latin Hypercube Sampling for eighteen design variables under four categories: layout, envelope, operation, and system. The analysis identified flat roof and external floor insulation as the most influential parameters, whereas lighting gain and cooling setback temperature were the least influential parameters. Furthermore, optimizing the reference building with the most sensitive design variables using a genetic algorithm based on the NSGA-II method found ideal configurations that would ensure minimum thermal discomfort hours during extreme summers. The study findings provide an evidence-based approach for building engineers and designers for early-stage design of assisted living facilities that maintain optimal comfort in mixed humid climates of Europe.

Multi-objective ventilation optimization for indoor air quality, thermal comfort, and energy conservation in the post-pandemic era: A case study for a moving elevator

Cases of respiratory disease transmission in enclosed elevators have been reported frequently. In the post-pandemic era, in order to mitigate the spread of respiratory diseases in moving elevators, a multi-objective genetic optimization method based on a response surface model is used to optimize the elevator ventilation. The ventilation parameters were optimized for three objectives: reducing carbon dioxide concentration, maintaining human thermal comfort, and achieving energy conservation. First, a response surface model is established using the computational fluid dynamics method and the Kriging model to correlate the design variables (air supply velocity in x, y, and z directions and air supply temperature) with the output function (CO2 concentration, average temperature, and average velocity). Subsequently, the Pareto optimal solution set of ventilation parameters was obtained by employing a multi-objective genetic algorithm. Finally, the optimal air supply velocity, angle, and temperature were obtained for both peak periods of elevator traffic (13 passengers) and other situations (4 passengers) when the elevator is moving up and down, which satisfy the objectives of health, comfort, and energy conservation.

Framework for optimising daylighting and passive indoor thermal comfort in single-banked office buildings in the temperate dry climate of Nigeria

Abstract Many researchers have differed on the optimum values of Daylighting and Passive Indoor Thermal Comfort (DPITC) determinants in tropical climates. The study is aimed at developing a framework for optimising DPITC in singled-banked office buildings, during the activity period (8 a.m. to 5 p.m.), in the temperate dry climate of Nigeria. It was achieved by evaluating the effects of orientation, window-to-wall ratio (WWR), R-values of external wall insulation material, and shading devices on DPITC. A quantitative research design using an explorative design approach was employed in the study as well as an experimental research strategy through simulation method to optimise DPITC. The study used the Federal Secretariat building of Nigeria as a prototype of a single-banked office building. The Google SketchUp Pro 2022 and OpenStudio 3.3.0 simulation tools were used to evaluate the prototype building from January to December 2023. The data generated was analysed using relevant statistical tools (MANOVA, ANOVA, column charts, graphs, and tables). The findings revealed that the best WWR for daylighting and passive indoor thermal comfort are 20% and 15% respectively, while the compromise value was 20%. It was also noted that the R-value of the external wall insulation material does not affect the daylighting of an office building but affects the passive indoor thermal comfort, where the optimum R-value was of 3.26 m2·K/W. The mathematical model was developed as A= 224.58 − 1254.84 WWR+ 102.87 PF − 4.11R … … .1 where A is orientation, WWR window-to-wall ratio, PF projection factor, and R is the R-value of the external wall materials.