Introduction

Thermal comfort in tropical architecture is shaped not only by temperature, but by the movement of air within space. In climates defined by heat and humidity, airflow plays a critical role in dissipating heat and reducing perceived temperature. However, its effectiveness depends not only on the presence of airflow, but on how it is distributed across space.

Rather than treating airflow as a passive outcome of design, this study positions air as a calibrated environmental system. Through simulation analysis, airflow becomes measurable, testable, and designable—allowing spatial decisions to be refined based on performance rather than assumption.

Airflow as a Calibrated Spatial System

This study operates at the spatial scale, focusing on how airflow can be calibrated within the interior through precise adjustments to opening configuration and spatial layout.

Small spatial interventions—such as the size, position, and type of openings—can significantly reshape how air enters, moves through, and exits a building. By analyzing internal flow velocity, the study reveals zones of stagnation, imbalance, and acceleration. However, increasing airflow alone does not guarantee improved comfort—balanced distribution across space is critical. The design therefore focuses on calibrating opening configurations to regulate airflow direction, velocity, and spatial continuity.

The objective is not simply to increase airflow, but to control how air is distributed across space. In this sense, openings act as environmental control devices that regulate movement, comfort, and spatial performance.

Findings: Airflow Calibration Through Openings

Initial simulations reveal that under existing conditions, internal airflow is limited, with velocities across most zones remaining below 0.3 m/s, indicating insufficient ventilation.

Through iterative adjustments to opening configurations, airflow behavior is significantly improved. Increasing and repositioning openings enhances cross ventilation, allowing air to move more effectively through primary occupied spaces.

For example, airflow velocity at key areas increases substantially following these modifications. However, the results also highlight an important condition: improvements are not uniformly distributed.

While some zones benefit from increased airflow, others may experience reduced velocity due to changes in pressure balance and flow direction. This demonstrates that airflow performance must be understood as a spatially interconnected system, rather than a set of isolated interventions.

Simulation Framework

The simulation is conducted under representative tropical conditions:

• External wind speed: approximately 0.75 m/s

• Outdoor temperature: approximately 30°C

Performance is evaluated through three key indicators:

Predicted Mean Vote (PMV)
A thermal comfort index that measures perceived comfort. Values approaching 0 indicate more comfortable conditions.

Uniformity Index (UI)
A measure of airflow consistency. Values approaching 1 indicate more stable and evenly distributed airflow.

Air Velocity
An indoor air velocity of approximately 0.5 m/s is considered effective for passive cooling without causing discomfort.

Conclusion

This study establishes airflow as a calibrated spatial system within tropical architecture. By controlling how air enters, moves through, and distributes across space, architects can improve environmental performance and indoor comfort.

However, airflow calibration alone does not fully resolve thermal comfort. While air movement enhances perceived cooling, it also introduces external thermal load into the building.

This reveals a second challenge: not only to shape how air moves, but to control the heat it carries.

Further Design Iterations (Analysis 3–5)

Based on the initial findings, three additional design scenarios are proposed to further refine airflow performance:

• Analysis 3
  An additional air inlet is introduced at Point D, while the opening at Point F is modified into a sliding window.

• Analysis 4
  An air inlet is introduced at Point D, while the openings at Points A and F are changed from casement windows to sliding windows.

• Analysis 5
  An air inlet is introduced at Point D, while the openings at Points A, E, and F are changed from casement windows to sliding windows.

Acknowledgment

Special thanks to Siree Thirakomen, MSc Renewable Energy and Architecture, University of Nottingham, for conducting the simulation analysis.

Simulation Analysis Chart 1

Simulation Analysis Chart 2

Simulation Analysis Chart 3

Simulation Analysis Chart 4

Simulation Analysis Chart 5

East Elevation

West Elevation

2nd floor Plan(Existing)

The initial simulation(Analysis 1) illustrates the airflow behavior within the existing building configuration. Results indicate that internal air circulation is minimal, with most measured values across reference points (A–F) remaining below 0.3 m/s. This suggests insufficient air movement and limited ventilation performance, contributing to poor thermal comfort.

Modified Opening Configuration (Analysis 2)

A second simulation was conducted by adjusting the size and configuration of openings to improve airflow distribution. The results demonstrate a clear enhancement in internal air circulation.

Notably:

• Air velocity at Point C (living area) increases significantly from 0.22 m/s to 0.68 m/s, indicating improved ventilation in primary occupied space.

• However, airflow distribution remains uneven. At Point D, velocity decreases from 0.28 m/s to 0.10 m/s, highlighting localized inefficiencies.

This suggests that while increasing and modifying openings improves overall performance, it may also create imbalanced airflow in certain zones.

Comparative Insight (Analysis 1–2)

The comparison between the first two simulations reveals that opening configuration plays a critical role in shaping internal airflow patterns. Strategic placement and sizing of openings can significantly enhance ventilation performance, but require careful calibration to maintain uniform distribution.

Keywords: Thermal Comfort, Airflow Simulation, Tropical Architecture, Passive Design, Natural Ventilation, Spatial Calibration, Internal Flow Velocity

Discussion

The simulation demonstrates that airflow is not a fixed environmental condition, but a design variable that can be calibrated through spatial decisions. Small adjustments to openings can significantly reshape internal air movement and improve ventilation performance.

However, the study also shows that more airflow is not always better. Comfort depends on the quality of airflow—its velocity, consistency, and distribution across space. A successful airflow strategy must therefore balance movement with spatial continuity.

Simulation plays a critical role in this process. It allows architects to test design scenarios, identify imbalances, and refine spatial strategies through measurable performance rather than intuition alone.

These iterations demonstrate that airflow calibration requires more than increasing the number of openings. It requires careful coordination between opening location, window type, air path, and internal spatial layout.

Design Strategies

The study identifies four key strategies for designing with air at the spatial level:

1. Calibrating Opening Configuration
The size, type, and placement of openings directly influence airflow behavior and must be carefully coordinated.

2. Enabling Cross Ventilation
Aligning openings across spaces allows air to move continuously through the building, reducing stagnant zones.

3. Supporting Vertical Air Movement
Voids and double-height spaces can support stack effect, helping warm air rise and escape from the interior.

4. Balancing Air Distribution
Effective airflow design must ensure that air reaches all occupied zones, avoiding both stagnation and excessive velocity.

Airflow performance is not defined by velocity alone, but by how effectively it is distributed across space.

Exsiting Condition

Modified Condition