Natural Ventilation Performance Research Articles

Comparative study on the performance of a solar photocatalytic Trombe wall with different types of collectors: Copper/Thermoelectric/PV plate

Solar photocatalytic Trombe wall (SPTW) is a technology that can help to improve the indoor environmental quality and simultaneously enhance solar energy utilization, which receives lots of attention recently. Nevertheless, current research predominantly emphasizes the heat and mass transfer analysis of a single envelope system, with limited exploration of energy and performance comparison of multi-physics systems. For this, flow, heat and mass transfer analysis of SPTW with four different types of collectors: SPTW with copper plate, SPTW with photovoltaic plate (PV-SPTW), SPTW with thermoelectric plate (TE-SPTW) and SPTW with hybrid PV-TE plate (PV-TE-SPTW), are theoretically proposed to reveal the energy flow distributions among these systems. Based on the coupled analysis, parameter characteristics have been conducted to investigate the effects of solar radiation intensity, system channel width and system channel height together with ambient temperature on the heating Q, purification CADR and power generation Z performance of various SPTWs. Furthermore, a comparison of the energy and exergy performance among these four systems is clarified through the energy, exergy flow and equivalent energy saving. From the obtained results, it can be indicated that the reverse flow has a strong impact on the performance of natural ventilation and further varies the indexes of Q, CADR and Z when the solar radiation intensity is inferior to a threshold value from 100 to 300 W/m2. With the changing channel height and width, the maximum Q and CADR are both appears in TE-SPTW system, respectively reaching by 4.64 MJ/h and 136.56 m3/h as the structure of 0.05 m channel width and 3.0 m channel height, which show 39.7 % and 5.9 % respectively compared to the SPTW model. Conducting energy and exergy analyses on the four systems reveal their remarkable potential, sacrificing a minimal 0.032 MJ or less in purification performance in exchange for substantial energy savings of at least 0.314 MJ. This work will establish a foundational contribution to advancing energy-efficient building technologies.

Performance of Lower Ventilation Opening to Improve Air Change per Hour in Classroom at Tropical Humid Region (Case Study: Palembang City)

Fresh air circulation in a room had an impact on indoor air quality. In today’s pandemic, good fresh air circulation is one of the main strategies to prevent viruses from spreading through air molecules. A good ventilation opening design influences indoor air exchange. This research conducts a test on lower ventilation opening design that can maximize natural ventilation performance in a classroom. This test aimed at a recommendation for schools in the tropical humid region so they can hold offline learning with low virus spreads. Natural ventilation optimization should be a solution because not everyone can afford mechanical air filters or virus killers. This research used an experimental method. Computer simulation test variables were classroom openings consisting of existing openings, new outlets/openings, and lower ventilation opening. Parameters of observation are wind velocity, air circulation pattern, and air change per hour. This evaluation compares the experiment result to Air Change per Hour (ACH) threshold limit provision required in Indonesia. The result of the experiment shows outlet/opening addition provides a better impact on ACH escalation than with only existing classroom opening. And when the existing opening is closed, lower ventilation opening had good performance in achieving the ACH threshold limit provision requirements which were 9,8 ACH.

Study of Natural Ventilation Strategies in the São Cristóvão Church in Lisbon Using a Multizone Airflow Model

Visitors have a significant impact on the indoor climate of buildings housing works of art, and the relationship between the number of visitors, the indoor air quality and the protection of exposed works of art is an important factor in the overall study of the indoor climate of heritage buildings without mechanical ventilation and/or air-conditioning systems. In view of these concerns and the lack of studies on natural ventilation in heritage buildings, this study aims to analyse the performance of natural ventilation in the São Cristóvão Church in Lisbon, Portugal. For the preparation of this study, an analysis of the natural ventilation of this church was carried out by creating a model in the CONTAM software, and the indoor air quality was analysed based on different international standards and guidelines for carbon dioxide levels and air flow rates (ACH). Estimating the current ventilation strategy, an average ACH of 0.75 h−1 was estimated during the time the church is open, and an ACH of 0.15 h−1 was estimated during the time the doors were closed. In a yearly analysis, an average ACH of 0.30 h−1 was obtained. These air exchange values guarantee EN 16798-1 category I air quality for 72% of the year and category II air quality for 18% of the year. Different natural ventilation strategies were analysed: (a) three scenarios exploring different cross ventilation scenarios; (b) a scenario assuming that the church is closed all year round; and (c) a scenario estimating an increase in the number of visitors, giving an idea of the variations in human pollutants and possible consequences. Taking into account the air infiltration and the fact that masses, an occasional situation with a high number of visitors, are always held just before the church closes, it is guaranteed that carbon dioxide levels will never exceed the limit of 350 ppm above the outdoor values imposed by EN-13779, registering a maximum of 291 ppm.

Impacts of horizontal and vertical louvers on the natural cross-ventilation performance of a generic building

Wind-based natural cross-ventilation is defined as a process in which fresh air is injected into a building via a high-pressure windward window and exhausts into the atmosphere through a low-pressure leeward window. There are several parameters that affect the natural ventilation performance, which should be considered in detail to reach the maximum air quality inside the buildings. In the present study, the effects of horizontal and vertical louvers on the wind-driven natural cross-ventilation performance of a generic building are assessed using computational fluid dynamics. In this regard, horizontal and vertical louvers with installation louver angles of 15°, 30°, and 45° are compared with each other and corresponding non-louver cases. Computations are carried out for three different free-wind speeds of 1, 2, and 3 m/s to show the impact of the external conditions on the natural ventilation of louvered cases. The obtained results revealed that under a low free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louvers with an installation angle of 15°, while at moderate and high free-wind speeds of 2 and 3 m/s, the horizontal louvers with an installation angle of 15° provide the best condition for a generic building. Highlights Effects of horizontal and vertical louvers on the wind-driven cross-ventilation were studied. At a free-wind speed of 1 m/s, the minimum age of air and maximum air exchange efficiency occur for vertical louver with α = 15°. At U H = 2 and 3 m/s, horizontal louver with α = 15° provides the best condition for a generic building.

Buoyancy-driven natural ventilation performance of a multi-story building with vertical shaft designed by using dimensionless design approach

Components with a tall vertical space attached to multi-story buildings are used to assist natural ventilation, which however unavoidably results in different buoyant forces on different stories. To achieve equal flow rates on all stories, a dimensionless design approach was developed in literature. This study aims to examine the reliability of the dimensionless approach for designing the buoyancy-driven ventilation of multi-story buildings. Moreover, it validates the application of the approach to scenarios where the heat source strengths on stories vary. The experimental and numerical results confirm the reliability of the dimensionless approach for designing naturally ventilated buildings with uniform airflow rates and air temperatures on each story. In the case of a story with flexible heat flux, changing the heat flux affects the ventilation rates on all the stories. In particular, when the heat flux on this story is zero, buoyant ventilation continues and may even be observed on the third story. Furthermore, an increase in the heat flux on the first or second story enhances stack ventilation, whereas increasing the heat flux on the third story has a damping effect on ventilation in the other stories. Additionally, stories with identical heat fluxes had similar ventilation rates and indoor temperatures.

Impact of planar area ratio and opening positions on natural cross ventilation performance in sheltered high-rise buildings: A simulation study

This paper studies the impact of planar area ratio (λP) and opening positions on natural cross ventilation performance of a sheltered three-level high-rise building through numerical simulations. Three building clusters of different λP and five different opening configurations each were assessed. To improve the accuracy of the numerical simulations, a novel calibration method utilizing 2k full-factorial design of experiment (DoE) approach was proposed to determine the closure coefficients of the Standard k−ε (SKE) turbulence model. Various parameters such as velocity profile (U/UH), pressure difference (ΔCp), turbulence kinetic energy (TKE), dimensionless flow rate (DFR), age of air (AOA) and air exchange efficiency (AEE) were examined. On level 1, distinct variations in DFR, AEE and AOA were observed for different λP values. Maximum DFR and AEE and maximum AOA are achieved when λP=0.25 for all opening configurations. Conversely, the impact of λP is minor for levels 2 and 3. Specific opening configurations, such as top-bottom and top-top on levels 1 and 2, and center-center and bottom-top on level 3, demonstrate favorable AEE of about 45–50%. The trade-off between AEE and DFR suggests that the bottom-bottom configuration performs best on level 1, while top-top and top-bottom configurations work best on level 2, and the center-center configuration is the best on level 3. The presence or absence of openings on levels 1 and 3 do not significantly affect the indoor airflow on level 2. The insights and recommendations derived from this study have practical implications for sustainable high-rise building design.

Effect of outdoor wind on the hybrid natural ventilation performance of monitor roofs

The monitor roof of a building has a raised structure running along the gable ridge, with its smaller roof parallel to the lower main roof. As a common building ventilation design, monitor roofs are expected to induce indoor airflow through thermal buoyancy and/or wind; however, studies on the design details and the induced natural ventilation performance are limited. In this study, how outdoor wind affects the efficiency of induced hybrid natural ventilation of monitor roofs was analyzed through computational fluid dynamics (CFD). Based on engineering practice and weather conditions, the Grashof number (Gr) was 2.11x1011-5.67x1011, and the Reynolds number (Re) was 2.5x105-1.7x106. The results indicated that for a larger monitor roof (width = 3 m, height = 1.2 m), the presence of outdoor wind combined with thermal buoyancy increased the ventilation rate to 1.5–3.5 times that found when only buoyancy was present. For a smaller monitor roof (width = 1.2 m, height = 0.3 m), Gr/Re2 = 0.45–3.2 was the transition range over which the presence of outdoor wind decreased the ventilation rate below that found when only buoyancy was present. Therefore, attention should be given to this disadvantage in ventilation design.

Simulation Study on Natural Ventilation Performance in a Low-Carbon Large-Space Public Building in Hot-Summer and Cold-Winter Region of China

Recently, climate governance has entered a new phase of accelerating decarbonization. In order to achieve low-carbon buildings, natural ventilation has been widely used as it requires no fan power. However, there are great challenges for achieving effective natural ventilation in large-space public buildings especially in areas characterized by hot-summer and cold-winter climatic regions, due to empirically unsuitable ambient temperatures and theoretically complex joint effect of wind pressure and thermal buoyancy. Therefore, this numerical study was conducted on the performance of a natural ventilation strategy in a large-space public building in a hot-summer and cold-winter region by using computational fluid dynamics (CFD) methods. Simulations were performed by applying FLUENT software for obtaining airflow distributions within and around a typical low-carbon public building. The temperature distribution in the atrium of the building was simulated particularly for analyzing the natural ventilation performance in a large-space area. Results demonstrated that thermal pressure was dominant for the large-space building in the case study. The average indoor airflow velocities on different floors ranged from 0.43 m/s to 0.47 m/s on the windward side which met indoor ventilation requirements. Most areas of wind velocities could meet ventilation requirements. The natural ventilation performance could be improved by increasing the relative height difference between the air inlets and air outlets. These findings could help provide references and solutions for realizing natural ventilation in low-carbon large-space public buildings in hot-summer and cold-winter regions.

Comparative assessment of night ventilation performance in a nearly zero-energy office building during heat waves in Brussels

With increasing urbanization, overheating intensifies, resulting in a greater risk of indoor overheating in commercial buildings, which already have high internal gains. The impact of urban climate on the cooling energy needs of buildings has been extensively researched. However, the building performance during extreme heat events needs further investigation to reduce the energy demand from the grid during critical events and to ensure an acceptable indoor thermal environment. Here, a comparative assessment approach for natural and mechanical night ventilation performance to reduce indoor overheating and energy needs of a nearly zero-energy office building in Brussels, Belgium, was evaluated for the heat wave and non-heat wave periods in urban and rural microclimates, using calibrated thermal-energy simulations. The analysis indicated that active cooling with natural night ventilation was more effective during heat waves than other cooling strategies. In addition, natural night ventilation was also effective in maintaining safer levels of heat index values in the reference office compared to other strategies. Natural night ventilation reduced overheating by 0.39 °C in the urban microclimate and 0.50 °C in the rural microclimate relative to the Baseline. Considering the cooling energy use, natural night ventilation had no significant impact. In contrast, mechanical night ventilation increased energy use by 0.54 kWh/m2 in urban microclimate and 0.40 kWh/m2 in rural microclimate due to prolonged ventilation fan operation in the reference office building. The presented findings in the paper lead to the formulation of design guidelines, recommendations for future practices and identifying needs for further research.

The effect of domed and hip roof coverings on mosque design in case of fire

The architectural design seeks solutions to many problems, one of which is designing buildings that can quickly and safely evacuate people. Mosques, which are places of worship and multifunctional gathering centers for Muslims, are significant buildings in terms of fire research because they often host many people at the same time. However, there is a lack of research on fire safety in mosques. This study focuses on the consequences of different scenarios and types of mosque roof design, with a capacity of 500 people, as produced by the Turkiye Presidency of Religious Affairs. The examined scenarios are Scenario 1 (500 kW fire size) and Scenario 2 (1000 kW fire size), and the investigated roof types of mosques are Type 1 (hip roof) and Type 2 (dome). In the analyzed scenarios, it was observed that the dome roof type in the examined mosque design extended the evacuation time by around 10–35%. The dome creates a space for storing smoke, which reduces the spread of smoke in the main room and raises the ASET. This study recommends expanding the scope of future research by incorporating a greater variety of fire scenarios and roof covering types in mosques, while also investigating the impact of natural ventilation openings on evacuation times.

Estimation of Natural Ventilation Rates in an Office Room with 145 mm-Diameter Circular Openings Using the Occupant-Generated Tracer-Gas Method

Natural ventilation in a building is an effective way to achieve acceptable indoor air quality. Ventilation dilutes contaminants such as bioeffluents generated by occupants, substances emitted from building materials, and the water vapor generated by occupants’ activities. In a building that requires heating and cooling, adequate ventilation is crucial to minimize energy consumption while maintaining healthy indoor air quality. However, measuring the actual magnitude of the natural ventilation rate, including infiltration through the building envelope and airflow through the building openings, is not always feasible. Although international and national standards suggested the required ventilation rates to maintain acceptable indoor air quality in buildings, they did not offer action plans to achieve or evaluate those design ventilation rates in buildings in use. In this study, the occupant-generated carbon dioxide (CO2) tracer gas decay method was applied to estimate the ventilation rates in an office room in Seoul, South Korea, from summer to winter. Using the method, real-time ventilation rates can be calculated by monitoring indoor and outdoor CO2 concentrations without injecting a tracer gas. For natural ventilation in the test room, 145 mm-diameter circular openings on the fixed glass were used. As a result, first, the indoor CO2 concentrations were used as an indicator to evaluate how much the indoor air quality deteriorated when all the windows were closed in an occupied office room compared to the international standards for indoor air quality. Moreover, we found out that the estimated ventilation rates varied depending on various environmental conditions, even with the same openings for natural ventilation. Considering the indoor and outdoor temperature differences and outdoor wind speeds as the main factors influencing the ventilation rates, we analyzed how they affected the ventilation rates in the different seasons of South Korea. When the wind speeds were calm, less than 2 m/s, the temperature difference played as a factor that influenced the estimated ventilation rates. On the other hand, when the temperature differences were low, less than 3 °C, the wind speed was the primary factor. This study raises awareness about the risk of poor indoor air quality in office rooms that could lead to health problems or unpleasant working environments. This study presents an example of estimating the ventilation rates in an existing building. By using the presented method, the ventilation rate in an existing building can be simply estimated while using the building as usual, and appropriate ventilation strategies for the building can be determined to maintain the desired indoor air quality.

Research on the influence of outdoor trees on natural ventilation performance of an academic building

Research on the influence of outdoor trees on natural ventilation performance of an academic building

An updated review of indoor pollutant purification by solar photocatalytic ventilation wall: Materials, modelling and performance evaluation

Solar photocatalysis has been an efficient option to eliminate indoor volatile organic pollutants (VOCs) due to its relatively low cost. Moreover, solar ventilation wall is a common heating and ventilating technology that supplies air circulation in a room and expels polluted air under the action of wind pressure. An efficient air purification type ventilation wall that meets indoor pollutant purification, natural ventilation and thermal fully driven by the combination of solar photocatalytic purification technology and natural ventilation wall has been developed by previous research. The aim of this updated review is to explore the development of the solar photocatalytic ventilation wall (SPVW) system and critically analyze the scientific literature on photocatalysts, models, mechanism, parameter analysis and evaluation of this multifunctional system. The review also included the effects of parameters such as initial concentrations of pollutants, ultraviolet (UV) light intensity, relative humidity, channel width, channel height on the solar photocatalytic characteristics and natural ventilation performance, and a brief performance evaluation on natural ventilation, indoor heating and solar photocatalytic degradation. The governing analysis reveals that the daily stability of the SPVW system could be achieved by enhancing the activity of the photocatalyst and decreasing fluctuation of light source in the external input.

Balcony design and surrounding constructions effects on natural ventilation performance and thermal comfort using CFD simulation: a case study

Despite natural light, near-façade structures’ impact on Natural Ventilation (NV) performance, reducing cooling demand, is usually ignored by designers. This article aims to characterize interactions between balconies’ design features (i.e. depth, unit level, and wind incident) and near-façade buildings on single-sided NV performance in a case study, representing medium to high-rise apartments in dominant cooling climates, utilizing validated Computational Fluid Dynamics (CFD) simulations. Results show that nearby buildings, even small structures close to the façade, significantly impact windward flow regime and indoor air movements. Nearby blocks might result in less air entering, which could be moderated by designing deeper balconies. Perpendicular wind incidents to the balcony opening may enormously improve single-sided NV performance. In contrast, wind incidents within higher degrees from perpendicular strongly reduce NV performance. This study provides designers with a method to characterize balcony design features’ effects on NV performance in apartments and improve it concerning urban design.

Analysis of the Ventilation Performance of a Solar Chimney Coupled to an Outdoor Wind and Indoor Heat Source

The effects of different solar radiation intensities, heat flow density of indoor heat sources, outdoor wind speed, and the relative location of indoor heat sources on the natural ventilation performance of solar chimneys are investigated through three-dimensional numerical simulations. The mechanism of the mutual coupling of the solar chimney effect with the outdoor wind and indoor heat source heat plume is explored. The results of the study show that when the structural parameters of the solar chimney are the same, the heat flow density on the surface of the indoor heat source, the outdoor wind speed and the solar radiation intensity all have a gaining effect on the ventilation performance of the solar chimney and the effects of the three on the ventilation of the solar chimney promote each other, when the solar radiation intensity is 200 W/m2, the outdoor wind speed is 1.0 m/s, and the indoor heat source heat flow density increases from 0 to 1 500 W/m2, the solar chimney ventilation volume increases from 0.393 m3/s to 0.519 m3/s, the maximum value of the increase is 32.1%. In the other two cases, the maximum increase in solar chimney ventilation is 176.7% and 33.1%, respectively. Under the same conditions, solar chimney ventilation is optimal when the heat source is in the middle of the room. The presence of outdoor wind, however, affects the optimum design parameters of the solar chimney. Compared to the case where no outdoor wind is taken into account, the optimum inlet width of 0.2–0.3 m for the solar chimney no longer applies with outdoor wind, with the optimum value rising to 0.5 m.

Analyzing the effects of passive design strategies on building ventilation performance and thermal comfort using simulation-based approach

One of the sustainable approaches to improving indoor thermal comfort and building ventilation efficiency, particularly in developing and populated countries, is to implement the optimum passive design solutions. However, the interaction between ventilation performance, indoor thermal comfort, and passive design features of buildings is scarcely studied in the domain of airflow modeling. Therefore, this study aims at assessing the ventilation performance and indoor thermal comfort with regards to passive design strategies, specifically, opening characteristics such as the Opening to Wall ratio (OWR) and Window to Wall ratio (WWR) in a Computational Fluid Dynamics (CFD) environment. The CFD simulations run is found pivotal for determining the spatial variation of Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) to gauge thermal comfort and the natural ventilation performance in terms of air change rate per hour (ACH). The proposed methodology is implemented in classroom spaces of an academic building located in a warm and humid region. In the study, a field investigation is carried out to collect precise temperature and air velocity data needed to validate the resulting CFD model. The findings show that increasing OWR and WWR percentages can enhance ventilation efficiency and indoor thermal comfort.

Exploring the impact of opening ratio on indoor thermal environment: A study on natural ventilation design

AbstractThe utilization of natural ventilation to reduce thermal load and enhance thermal comfort in buildings is on the rise. Furthermore, in light of the COVID‐19 impact, natural ventilation is gaining prominence as an increasingly vital technology. However, it is crucial to address potential challenges associated with natural ventilation, particularly its impact on the indoor thermal environment. This study aimed to examine and offer insights into natural ventilation design and operational strategies for office buildings. We initially summarized the criteria and effective opening area of natural ventilation openings (αAi) in Japanese naturally ventilated buildings. Among the 37 investigated office buildings, we found a positive correlation between the natural ventilation room area and the αAi. Approximately, 25 buildings maintained a ratio of αAi to the natural ventilation room area ranging from 0.1%–0.5%. Additionally, we conducted measurements of the indoor thermal environment, focusing on the opening ratio of natural ventilation openings. The difference of indoor and outdoor temperature showed a strong negative correlation with the opening ratio, while wind direction and global solar radiation exhibited significant correlations as well. These research findings provide valuable insights for future natural ventilation designs and the incorporation of opening ratio concepts into operational methods.

Control of Natural Ventilation Opening to Achieve Energy Saving Performance and Thermal Comfort in Office Room

In recent years, the number of office buildings that introduce natural ventilation (NV) is being increased to save energy. However, operating NV systems with NV opening device fully open could lower thermal comfort, depending on meteorological condition. Therefore, automatically-controlled NV systems can generally work only for a relatively short period of time. In order to keep both energy saving performance and thermal comfort even when outdoor temperature is low in the mid-seasons, it is necessary to understand the relation between NV conditions and the indoor environment. In this paper, the indoor environment is evaluated changing NV conditions by using CFD for a generalized office room model. Four types of NV inlet system were assumed, i.e., high peri-counter (Type 1), low peri-counter (Type 2), slot-type downward inlet (Type 3), and slot-type horizontal inlet (Type 4). Twenty conditions were analyzed for each type, varying the outdoor air temperature and NV flowrate as parameters. As indices of thermal comfort, average vertical temperature difference within perimeter zone and ADPI in the occupied zone were calculated. For each of NV systems, simplified equations to calculate Nmax from indoor/outdoor temperature difference are finally to be proposed, which may be considered for NV opening control in operating NV systems.

Investigating natural ventilation performance on apartment units in Jakarta based on field test measurements

The COVID-19 pandemic has changed the way of living of many people across the planet. In the beginning of the pandemic, when the strict lockdown was implemented, numbers of individual were encouraged to work from home. In the city living, high rise living were apparent and became a global phenomenon. This paper evaluates natural ventilation performances of existing apartment units in Jakarta, Indonesia by measuring the indoor temperature, indoor airflow and relative humidity. This research studied three different apartment units in Jakarta in the form of single-sided ventilation or cross ventilation. This study conducted by field test measurement on three different apartment units across Jakarta with various natural ventilation strategy and room volume. Statistical analysis was carried out to investigate the relationship and influence between the results of field test measurement and external weather data collected from ERA5. The results of the analysis suggested that external weather influence the indoor air condition, especially indoor temperature where significant influence was apparent. Furthermore, the field test data measurement in this paper contributed to validation study in predicting indoor airflow.

EVALUATING THE EFFECT OF MASHRABIYA AND PERFORATED MALAY CARVING WINDOW ON THE INDOOR NATURAL VENTILATION PERFORMANCE OF LIVING SPACE

This study focuses on natural cross-ventilation improvements in terms of internal air velocity, measured in meter per second in the living room space in Malaysia, using two types of perforated windows namely, Mashrabiya window as well as perforated Malay carving window element to determine the performance of their internal air velocity. Cross ventilation has been proposed as one of the most effective natural ventilation methods for thermal comfort by several studies. It is, however, one of the most misunderstood aspects of passive design's approach to regulating interior temperature. In this study, the proposed design solution is by introducing the Mashrabiya (W1) and perforated Malay carving window (W2) as two predominant indigenous solutions for traditional houses that can be further developed and utilized in modern houses. The research involves three stages. The first stage includes the inventory exercise on five (5) different reference case studies of perforated windows. This is to ascertain the most fundamental and common pattern, as well as the dimensions of each W1 and W2. The second step involves computer simulations utilising Computational Fluid Dynamics (CFD) software known as Ansys fluent R2 2021. This program is used to simulate and evaluate natural air velocity and its performance in an interior context, and to determine the viability of a recommended design solution. Finally, an empirical method is used to predict the internal air velocity. The result shows that W1 and W2 represent effective passive design strategies for energy saving. The air velocity using W1 is three times higher than the normal speed which is 4.5/1.5 m/s, while using W2 makes the air velocity two times higher than the actual air speed which is 3/1.5 m/s. The simulation test and results are discussed based on the Malaysian region with a 1.5m/s wind speed. Understanding the different effects of the size of the voids and the placement of the patterns are significant to improve the indoor natural ventilation performance in a living room space.