Thermal Comfort Level Research Articles

Effect of Street Asymmetry, Albedo, and Shading on Pedestrian Outdoor Thermal Comfort in Hot Desert Climates

Improving urban walkability in the face of climate change is a critical challenge for urban designers. Street design strategies can mitigate heat stress and enhance pedestrian livability. Most previous studies conducted in hot climates recommend adopting deep canyons to improve summer conditions, overlooking the potential improvement of wide streets as essential structural elements of the urban fabric. This study was conducted in Biskra city, southern Algeria, where several mitigation strategies were applied to ‘Emir Abdelkader Boulevard’, as the main structural street inside the city, to create an optimal street model for arid climates. Five scenarios were developed based on three criteria: (Sc1) asymmetric profile northeast side (NES) > southwest side (SWS); (Sc2) asymmetric profile SWS > NES; (Sc3) cool paving; (Sc4) horizontal shading; and(Sc5) shading with a linear tree arrangement. ENVI-met software version 5.1.1 and the RayMan model were used to estimate the local climate conditions and outdoor thermal comfort levels based on the physiological equivalent temperature (PET). All scenarios reduced PET values across the street, with optimal reductions of −2.0 °C, −3.1 °C, −1.3 °C, −1.7 °C, and −1.2 °C in Sc1, Sc2, Sc3, Sc4, and Sc5, respectively. Concerning pedestrian areas, the optimal results durations were at the southwest side below the arcades’ sidewalks during peak hours: Sc2, Sc3, Sc4, Sc5 (2.2 °C–3 H, 2.3 °C–3 H, 2.4 °C–3 H, 2.5 °C–2 H). Sc1 performed best during daytime hours on the northeast side. The utilizing of these results can strongly help urban planners and landscape architects in creating climate-responsive streets that enhance citizens’ quality of life.

Bioclimatic approaches of modern residential architecture in Cyprus, 1952-1974

. In terms of energy efficiency, bioclimatic architecture aims at minimizing the energy consumption of the building and at achieving control of the microclimate of the indoor spaces. The bioclimatic dimension of residential architecture in Cyprus is examined on the basis of residential buildings, designed in the period 1952-1974 by the Cypriot architect Neoptolemos Michaelides. The selected projects are of a high national architectural significance, as they represent in a most distinct way a critical introduction of modern architecture in Cyprus. In architectural terms, the designs follow the functional disposition, without relying on symbolic or decorative parameters. Following an overview of modern architecture in Cyprus, in the specific period, the main climatic conditions of the region and the thermal comfort criteria are briefly presented. The analysis of five residential buildings, situated in the broader Nicosia district refers to the architectural design strategies, and the construction materials and systems, applied for achieving human comfort, as regards cooling and natural lighting. The study proves that a series of strategic design actions ensure thermal improvements of the buildings and lead to optimum levels of thermal comfort, enabling thus substantial energy profits.

From Double Skin Facade to Closed Cavity Façade with Triple Glazed Unite as Inner Skin Without Coatings in the Tropical Climate of Malaysia

The Close Cavity Façade (CCF) has undergone significant advancements from its predecessor, the Double Skin Façade (DSF), resulting in improved thermal insulation and reduced solar penetration. The core principle behind a CCF is a hermetically sealed and non-ventilated construction that incorporates an automatic shading system, triple glazing (TGU) on the inner surface, and single glass on the outer surface. The technique described above effectively regulates the ingress of solar energy and natural light into the building. The experimentation involved the utilisation of various combinations of CCF-TGU designs, employing software tools such as Window 7.8, EnergyPlus, and DesignBuilder. Then, a comparison analysis was undertaken to compare the aforementioned designs with the presently employed single-glazed units (SGU) featuring a grey coating. The inquiry was initiated through the implementation of a case study carried out on a condominium located on Penang Island, Malaysia. The CCF-TGU has superior thermal performance and provides enhanced occupant comfort when compared to SGUs. The effectiveness of CCF-TGU designs in reducing operating temperature ratios has been observed to be higher in Malaysia's humid tropical climate than that of SGUs. The annual rate of decrease varies between 29.8% and 77.8%, thereby successfully attaining the required level of thermal comfort. The research highlights the potential advantages of implementing an innovative CCF technology that has been modified to accommodate the distinct meteorological conditions of Malaysia. The findings suggest that the implementation of advanced glazing technology holds the potential to enhance both operational temperatures and overall occupant comfort within buildings.

Analysis of the indoor thermal environment and livability of traditional residences in summer in Northeast Sichuan, China

Abstract 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 onsite measurements and questionnaire surveys during summer in the indoor environment of five villages in northeastern Sichuan. A total of 89 traditional residences were selected to investigate their fundamental characteristics, indoor thermal environment, humidity conditions and comfort levels. The results showed that when expressed as neutral temperature and humidity, the temperature difference was 1.35°C and the humidity difference was 8.14%. Local residents exhibited higher tolerance toward the local thermal and humidity environment compared to nonlocal volunteers, who displayed greater sensitivity toward it. In addition, local residents had a thermal comfort value of 0.03 and a thermal acceptance value of 1.16, whereas nonlocal volunteers had a thermal comfort value of 1.42 and a thermal acceptance value of −0.45.

DeepVision based detection for energy-efficiency and indoor air quality enhancement in highly polluted spaces

Cooking can generate substantial heat from cooking equipment, potentially resulting in reduced thermal comfort levels if this excess heat is not adequately dissipated. Additionally, it can significantly affect indoor air quality (IAQ), not only in kitchen spaces but also in adjacent areas lacking sufficient ventilation. To ensure a healthy and comfortable indoor environment while avoiding unnecessary energy use, this research proposes an approach for detecting equipment usage. Utilizing deep learning and computer vision techniques (referred to as DeepVision), this method aids the operation of demand-driven ventilation systems in highly polluted spaces. A Faster RCNN model was employed and trained to detect kitchen equipment usage in real-time. The ventilation rate for the kitchen space was adjusted based on this real-time detection. Experimental tests were carried out in a case study kitchen and results showed that the detection model achieved an overall F1 score of 0.9142. Overall, the model achieved good performance in real-time detection, accurately identifying appliances in use, such as stoves, ovens, and toasters. Field experimental results showed the advantages of combining mechanical ventilation methods, such as extractor fans and cooker hoods, to mitigate IAQ issues while also achieving energy savings. Moreover, the energy simulations demonstrate its potential to reduce energy consumption by dynamically adjusting ventilation rates in response to real-time equipment usage. When the fan speed was varied according to the real-time detection method, the PM2.5 concentration in the cooking period was 16.5 % lower, with only a 3.7 % rise in fan power and a 0.8 % rise in daily heating demand, compared to using a constant fan speed.

Economic viability of under floor heating system: a case study in Beirut climate

This paper explores the economic feasibility of the underfloor heating system for the climatic conditions of Beirut. A case study of a typical residential room (150 m2 ) is selected to compare its heating energy requirement when using either the conventional convective heating system or the underfloor heating system at similar comfort and indoor air quality conditions. Two mathematical models are developed, a steady space thermal model to establish the energy consumption at the peak load and a transient simulation model to find the energy consumption during the winter heating season. In addition, the economic feasibility of the underfloor heating system is assesd when integrated with solar energy. Based on the steady space model, the calculated peak heating load is reduced by 20% when the test space is heated by the underfloor heating system and a thermal comfort level of PPD 18.3% is achieved for a floor temperature of 27.4 ºC. The simulation results of the transient space model indicates that the seasonal heating energy consumption is reduced by 18% and that the yearly energy savings is $104 for an on-off control strategy that maintains a PMV comfort level greater than -0.5. The pay back period of the underfloor heating system is 10 years for an initial incremental cost of $850. When integrated with 10 solar collector units, the yearly energy savings of the integrated system is increased to $350 and the pay back period is 14 years.

Experimental Study of the Effects of Siestas on the Nocturnal Sleep Quality and Thermal Comfort Levels under Thermoneutral Environment in Summer

It has been determined that siestas could potentially have both mental and physical influences on the human body. However, the effects of siestas on the nocturnal sleep quality and thermal comfort levels under thermoneutral environment had not yet been examined in detail. In order to explore the potential influences of siestas on nocturnal sleep, twenty subjects were recruited and divided into two groups based on whether they took siestas or not. During this study's experiment, the temperature was maintained at 25°C, and sleep duration was recorded throughout the night. In addition, thermal comfort votes (TCV) and thermal satisfaction votes (TSV) were obtained both before and after the nocturnal sleep. Furthermore, dopamine (DA) levels, which played important roles in emotional regulation, were measured after the nocturnal sleep. Results showed that the siesta group had a significant increase in self-reported nocturnal sleep quality (p < 0.05), although slight decreases in slow-wave sleep (SWS) duration and rapid eye movement (REM) duration were observed. Additionally, higher TCV and TSV values were reported in the siesta group (p < 0.05). Higher DA concentration was also detected in the siesta group after the nocturnal sleep. Furthermore, some correlations were illustrated between the thermal voting values and the sleep duration, as well as the DA concentration levels. Results implied that siestas could have an influence on the nocturnal sleep quality and thermal comfort levels under thermoneutral environment. Besides, DA concentration levels played an important role in the thermal comfort evaluations when exploring the influences of siestas on nocturnal sleep.

The Analysis of the Impact of Building Openings Design Variations on Thermal Comfort and Airflow Velocity by using CFD Simulation

Thermal comfort is very important to support a building’s user productivity. This study was conducted to investigate thermal comfort and airflow velocity in the engineering laboratory building at the State University of Malang.Preliminary observations have shown that the average room air temperature was around 27 - 31°C, which caused the uncomfortable condition. Thermal comfort enhancement in this study is investigated by applying several variations and treatments to existing openings. By using descriptive quantitative and experimental methods, the analysis uses the Computational Fluid Dynamics (CFD) simulation method with the ANSYS Workbench 19.0 Program. The simulation was applied to seven rooms with various types of openings. Parameters used in the simulation process are: 1) room geometry data consisting of images, room area, and location of ventilation openings, and 2) measurement reference points such as airflow velocity and room temperature. The dimensions of the openings will be observed by varying the treatment in each room, namely by opening all the inlets in the room (S), opening the inlets on the air vents only (J), and opening the inlets on the windows only (V). Primary data in the form of room temperature, airflow velocity, relative humidity, and physical dimensions of buildings are obtained through direct observation. The simulation results show that the maximum airflow velocity of the rooms (0.34 m/s) is found in the largest dimension variation of the inlet area of the opening (13.15 m2). The lowest temperature is found in the rooms with the smallest dimension of inlet (28oC) with the value of room temperature in the range of 27.5oC – 30.2°C. The statistical analysis of one-way ANOVA shows that by using a significance level of 0.05, there is an effect of variations in the design of openings on the level of thermal comfort in each room.

Sick Building Syndrome (SBS): A Proactive Mitigation Strategy Focused on University Office Buildings in the United Kingdom

Since most people spend more time at work in recent times, this has led to more workplace issues and health problems. The well‐being of occupants and their overall health are strongly impacted by factors that determine the standard of indoor environments. These factors include the air quality, the level of thermal comfort, the inclusion of indoor plants, the admission of daylighting, and a variety of other factors. The absence of any of these may result in sick building syndrome (SBS). Therefore, well‐planned indoor workspaces are vital for occupants’ health and productivity at work. The aim of this article is to investigate proactive measures for mitigating SBS in office buildings located within universities in the United Kingdom. The study administered a questionnaire to gather perceptions of office occupants, followed by a comparative case study analysis of two office buildings at the University of Greenwich located on different campuses to highlight the correlation among the physical parameters of indoor office spaces and the occurrence of SBS. The results showed that a notable percentage of participants reported experiencing at least two symptoms of SBS. This study provided clear evidence that symptoms of SBS are primarily associated with the physical characteristics of the building, and these elements significantly influence the occupants’ experiences. The mitigation of potential adverse effects on the well‐being of inhabitants during the operating phase of a building resulting from physical variables can be achieved by the implementation of conscious design considerations during the initial planning stages of future buildings. One of the practical implications of this study is that it raises the urgency for built environment professionals to be fully aware of how their design decisions could either contribute to or prevent SBS symptoms.

THE LEVEL OF THERMAL COMFORT IN THE TRANSITION AND SUMMER PERIOD FOR PRESCHOOL EDUCATIONAL INSTITUTION

Modern cities are trying to actively reduce energy consumption and carbon emissions during construction, directing their efforts towards achieving sustainable environmental balance. The issue of thermal comfort is becoming increasingly important in the global context, especially in the context of a rapid reduction in energy consumption. The purpose of this study is to assess the level of thermal comfort for the most sensitive segments of the population, in particular preschool children, during the transition and summer periods of the year. Using computer modeling, we determined the energy demand for cooling and additional heating during the transition period at different levels of thermal protection of buildings and different coefficients of clothing resistance. The results of the study confirm that improving the thermal protection of buildings and optimizing temperature control systems, taking into account the thermal resistance of clothing, will maintain the level of thermal comfort, measured by the PMV indicator, within the recommended range of -0.5...+0.5. This will help create comfortable conditions for the most sensitive segments of the population. However, it is important to note that such improvements are accompanied by an increase in energy consumption for heating during the transition period at 11.5% of total energy costs. Thus, these results emphasize the need for a balanced approach to ensuring thermal comfort and optimizing energy consumption in buildings for the most sensitive segments of the population.

Thermal Comfort Analysis in the Classrooms of the Faculty of Islamic Education and Teacher Training at UIN Raden Intan Lampung

Thermal comfort in the classroom environment serves as a crucial factor influencing the quality of the teaching and learning process. Preliminary research reveals that a significant number of students at UIN Raden Intan Lampung have expressed complaints regarding excessively hot classroom conditions, lacking adequacy in creating comfort. The primary objective of this study is to assess the extent to which the level of thermal comfort can be achieved in the classrooms within the Faculty of Islamic Education at UIN Raden Intan Lampung. The research methodology applied in this study is qualitative and descriptive, with a focus on variables such as temperature, humidity, wind speed, and lighting levels. The purposively selected sample indicates that the classroom conditions in the Faculty of Islamic Education at UIN Raden Intan Lampung have not yet met the desired standards of thermal comfort.

Effects of different zoning thermostat controls on thermal comfort and cooling energy consumption in reading rooms of a library

This study assessed thermal comfort and energy consumption in indoor environments controlled by air or operative temperature. Reading rooms in a library were divided into several zones based on the distribution of operative temperature. Using air temperature of the inner zone in thermostat control yielded the lowest energy consumption but the poorest thermal comfort level. Conversely, using operative temperature of the least favorable exterior zone resulted in higher energy consumption and comfort levels. The suggested optimal control based on switching boundary temperature minimized energy consumption while satisfying the thermal comfort requirement. The switching boundary temperature range on the top floor is 0.7 °C lower than on the middle floor due to the influence of the roof. The thermostat control modes had similar effects on the east and west reading rooms. The switching boundary temperature ranges of north room was 2.0 °C higher than those of the south room. Zoning control using air temperature control in the inner zone and operative temperature control in the exterior zone was recommended as a much simple mode to keep thermal comfort with low energy use. This study provides insights about the use of operative temperature in zoning thermostat control and theoretical guidance for practical implementation.

Numerical study of vegetation effects on thermal comfort for outdoor spaces at a public school in hot and arid climate

School outdoor spaces are important for students as they impact learning outcomes, physical and mental health, social interaction, and overall well-being. In hot, arid climates, the use of outdoor spaces becomes a challenge. The high levels of thermal stress impact outdoor thermal comfort during the warmer months, leading to limited or no use of those spaces. This paper assesses vegetation as a passive cooling strategy for an elementary public school in the city of Riyadh, Saudi Arabia. Air temperature (Ta), mean radiant temperature (Tmrt), and Universal Thermal Climate Index (UTCI) are used to investigate outdoor thermal comfort. The experimental approach adopted in this study compares a base model against eight scenarios, which simulate different vegetation (grass, shrubs, two trees at two different heights, 5-10 m) and spacing between them (3.5 m and 7 m). The data is simulated using Envi-Met 5.5 and assessed for their impact on thermal stress levels for the school outdoor space. The results found that by applying trees 10 m high with 3.5 m spacing between them and using evergreen type leaves, Ta was reduced between (1.4-3.2)°C reaching max reduction in August, Tmrt (7.13-64.73)°C where max reduction was recorded in October, and UTCI at (3.00-17.95)°C in April. Therefore, the study offers solutions for existing schools or future ones to enhance outdoor thermal comfort.

STUDY OF THE ROLE OF GREEN OPEN SPACE IN DKI JAKARTA AS AN AMENITY INFRASTRUCTURE

Green open spaces are often incompatible with the functions they should have. In the last few years, DKI Jakarta has continued RTH construction, but the implementation has been neglected, resulting in non-compliance with RTH requirements. Green open spaces in Kota Hijau are frequently located in the outskirts of DKI Jakarta, yet, in reality, the area allocated to green open space has not met the mandated 30% minimum requirement. The creation of well-designed green open spaces is crucial to providing essential amenities for the community. This study aims to analyze thermal comfort levels, community activities, and security in three parks in DKI Jakarta. The average Temperature-Humidity Index (THI) value of 24.5 suggests favorable conditions below the threshold of 27. Although the current state is considered satisfactory, continuous monitoring and efforts are recommended to maintain optimal THI conditions. Additionally, an evaluation of visitor comfort in the Green Open Spaces (RTH) of DKI Jakarta, based on a questionnaire, revealed a reasonably comfortable score of 3.6 out of 5. Consequently, there is a need to improve facility quality to enhance visitor comfort. The security questionnaire results from three parks in DKI Jakarta indicate a sufficiently safe environment, with an overall score of 3.6 out of 5. However, it is advisable to augment security facilities and personnel to further enhance the sense of safety for park visitors. In conclusion, this research underscores the importance of optimizing and expanding green open spaces in DKI Jakarta, not only for thermal comfort but also for the overall well-being, security, and recreational needs of its urban residents.

The dilemma of variables assumptions in thermal comfort calculations for educational buildings: To Simplify or Not?

Thermal comfort is crucial for people well-being and productivity in buildings, and it has a strong effect on building's energy usage. The main models for assessing thermal comfort, like predictive mean vote (PMV) and adaptive models, need many environmental measurements, making monitoring complex. That has sparked a debate: some advocate reducing the number of variables, while others stress sticking to the original models.This article evaluates current research trends and addresses the limitations of globe sensors, the most commonly used instrument for measuring mean radiant temperature. To address these issues, the study conducts a sensitivity analysis using latin hypercube sampling with multidimensional uniformity and employs data from 41 measurements conducted in educational buildings spanning different academic levels, from preschool to university. This analysis examines various simplifications in the measuring procedures for the PMV and adaptive models proposed by ASHRAE 55, ISO 7730 and EN 16798. For this purpose, two mean radiant temperature accuracies are used according to the minimum requirement and the desired value specified by ISO 7726, ±2 °C and ±0.2 °C respectively. The results suggest that models with fewer variables tend to overestimate thermal comfort levels. However, this models are valid as their estimations fall within the uncertainty range of the complete model, as long as the mean radiant temperature accuracy is ±2 °C as achieved with globe sensors. When mean radiant temperature accuracy improves (i.e. ±0.2 °C), the outcome of the models with less variables imply an overestimation falling out of the uncertainty of the complete model.

Development of the Universal Standard Effective Temperature for evaluating thermal comfort across different metabolic rates

The standard effective temperature (SET) is a widely recognised index in thermal comfort studies worldwide. The definition of the standard environment is crucial to the validity of SET. It allows SET to evaluate thermal comfort levels in various clothing insulations, air velocities, and metabolic rates. The thermal sensation votes (TSV) should be equivalent when the SET remains constant. Previous studies have focused on applying SET to analyse thermal comfort with diverse environmental factors or clothing insulation conditions but have not compared SET with different metabolic rates. In this study, the original standard environment was examined using experimental results with different metabolic rates. The results revealed that the original standard environment failed to guarantee the ‘same SET, same TSV’ principle with different metabolic rates. The original standard environment was insufficient in accurately reflecting the effect of the actual activity status on the standard convective heat transfer coefficient and standard clothing insulation. Thus, a new standard environment was developed, incorporating two new variables: the base value of the standard clothing insulation and the convective heat transfer coefficient generated from the actual activities. Through validation of the experimental data, the new standard environment ensured a consistent linear relationship between SET and TSV, in both transient and steady-state conditions, even when the metabolic rate was changed from 1.0 met to 3.8 met. Furthermore, a universal SET was proposed. The universal SET could be applicable to thermal comfort analysis with different metabolic rates in steady-state conditions and activity status transients.

Urban tree canopies drive human heat stress mitigation

Climate warming and urbanisation compound the public health risk posed by heat. Heat can be mitigated at local scales through urban greening, which provides shade and reduces surface and air temperatures. Yet, the relative effectiveness of different greening options on human thermal comfort based on physiology-based indices is understudied. We installed microclimate stations at 17 locations covering a gradient of tree canopy cover and perviousness in the city of Ghent, Belgium, and monitored the modified Physiologically Equivalent Temperature (mPET) during 195 days over Spring and Summer. We assessed the canopy cover, pervious surface fraction and building sky fraction based on field measures and hemispherical pictures. Unpaved locations with trees experienced a 2.4-fold reduction in the number of days with strong heat stress (mPET > 35 °C) compared to paved, treeless locations. Based on mixed models and our selected environmental variables, cooling effects were predominantly driven by tree canopy cover, where locations with 100% canopy cover had temperature maxima 5.5 °C mPET lower than treeless locations throughout the monitoring period. When air temperatures rose to 40 °C, cooling by tree canopies increased to 8.8 °C mPET. The pervious surface fraction and building view factor were less influential, generating variation of at most 1.7 °C and 1.1 °C mPET, respectively. In contrast, night-time temperatures were rather determined by the regional-scale urban heat island effect than by aforementioned local factors. Still, tree canopies slightly cooled the warmest nights only, whereas the vicinity of buildings led up to 1.2 °C mPET warming on average. Expanding the urban tree cover may therefore be the best solution for improving local thermal comfort levels when daytime heat peaks, but will provide little relief at night.

Thermal Comfort Level and the Ability of Trees to Reduce Temperature at H. Agus Salim Sports Hall, Padang City

Changes in land cover are thought to be the main factor in the Urban Heat Island (UHI) phenomenon. UHI is a form of local climate change which is characterized by an increase in temperature reaching 6oC in central urban areas compared to vegetated areas on the outskirts of the city. Compact vegetated land or Green Open Space (GOS), which is able to avoid increasing the surrounding temperature. GOR H. Agus Salim as one of the GOS in Padang City is a place for residents to have recreation and fill their free time by enjoying various culinary delights with friends and family as well as sports activities. This research aims to measure the benefits of tree canopies as climate amelioration in the H. Agus Salim GOR area. The research was conducted in September 2023, with 7 repetitions at 5 measurement points (3 under the tree canopy and 2 in the open field). Data is measured directly in the field with a thermohygrometer. The cooling effect provided by trees was analyzed using a difference approach between measurements in shade and open areas. Thermal comfort level is measured using the empirical formula Temperature Humidity Index (THI). The results showed that there was a decrease in temperature under the tree from 2,0oC (in the morning) to 2,9C (in the afternoon). However, THI calculations show that GOR H. Agus Salim is in the Uncomfortable criteria both under a canopy and in open areas.

Natural Ventilation and Indoor Air Quality in Domestic School Building: CFD Simulation and Improvement Strategies

Natural ventilation is a process of replenishing used air from the interior environment with fresh outer air without the use of mechanical equipment. This project aims to investigate the feasibility and performance of implementing natural ventilation in dilapidated classroom designs of actual geometry. Computer models of an existing classroom were created using SOLIDWORKS based on real-scale building floor plans, while the same software was applied to compute flow simulation studies to visualise the airflow pattern, temperature distribution, relative humidity, and the thermal comfort level of occupants in the classrooms. Estimated climate parameters were input in the simulation process to illustrate better the effect of hot and humid climate conditions in Malaysia towards the thermal comfort level of occupants. In this project, a visualised wind tunnel was created to simulate the prevailing wind source that supplies wind to the designed classroom, and the airflow pattern across the designed building was analysed. From the initial simulation results, it was discovered that the airflow into the classroom is uneven, whereby some locations in the building are experiencing extremely low wind breeze, which eventually affects the comfort level of occupants in the room. On the other hand, an internal analysis focusing on the interior comfortability of the classrooms was applied to examine the thermal comfort condition while using the naturally ventilated classrooms. Recommendation optimisation approaches such as the louvre angle and introduction of a windcatcher was presented in this project to improve the natural ventilation performance of the designed classroom.

Study on Microclimate and Thermal Comfort in Small Urban Green Spaces in Tokyo, Japan—A Case Study of Chuo Ward

Small urban green spaces are abundant in densely populated urban areas, but little is known about their impact on the urban heat island effect and thermal comfort. Therefore, this study selected as research sites four small urban green spaces in a typical high-density built-up area, Chuo Ward in Tokyo, Japan. The ENVI-met software 5.1.1 simulation method was used to analyze these sites’ microclimate and thermal comfort conditions. The following are the results: (1) Small urban green spaces significantly reduce urban air temperatures, particularly during hot weather, with temperature reductions ranging from 2.40 °C to 2.67 °C, consistently lower than the highest temperatures in Tokyo’s Chuo Ward, mainly between 1:00 and 2:00 p.m. (2) Thermal comfort analysis indicates that small urban green spaces can significantly improve urban thermal comfort during the day, particularly around noon, by reducing one or two thermal comfort levels compared to typical urban street blocks. However, these differences gradually diminish throughout the evening and night, and thermal comfort inside and outside green spaces becomes more uniform. (3) Green space size is not the only factor influencing thermal comfort; the layout of plants within the green space and the layout of the surrounding buildings also have an impact. Despite their small size, even small green spaces can significantly enhance comfort. This study highlights the need to promote urban sustainability through the extensive integration of small green spaces in dense urban environments. Small green spaces can serve as a high-frequency, low-cost solution for environmental sustainability by addressing the increasingly severe urban heat island effect as well as environmental challenges that in the urbanization process.