Bioclimatic Design Strategies to Improve Thermal Comfort and Indoor Air Quality.

Bioclimatic design is an approach to building design that harnesses natural resources like sunlight, wind, and vegetation to create comfortable and healthy indoor environments. Malaysia is a region with hot and humid climate, thus the only way in which we can cope with this climate condition is to adapt rapidly to living in a warmer world, and fundamental to this adaptation in the built environment is the adoption of more effective, and widely used, methods for passively cooling buildings. Creating comfortable and healthy indoor environments in Malaysia requires going beyond conventional air conditioning and embracing bioclimatic design, a holistic approach that harnesses natural resources to achieve thermal comfort and human well-being. This essay explores how bioclimatic strategies can be effectively implemented in hot and humid regions to improve thermal comfort and safeguard occupant health.

 

In 2015, the government of Malaysia announced the construction of one million affordable housing units within the well-known social housing programme called People’s Housing Programme (PPR), coordinated by the National Housing Department (NHD) of the Ministry of Urban Wellbeing, Housing and Local Government (UHLG) and now is known as Ministry of Local Government Development. In PPR Housing development projects, there are also community facilities such as community hall, praying hall, stall, kindergarten, OKU units and green area. As a hot and humid climate country, PPR housing project experiences high temperature, excessive humidity and low air movement much of the time. In urban areas, especially, these challenging factors are worsened by the poor air quality coupled with high energy demand (Mohd Sahabuddin & Gonzalez-Longo, 2017). 

Natural ventilation, which is a common method used in tropical climate countries, the mechanism of natural ventilation in buildings can attribute to two fundamental principles. The first one is wind- driven ventilation (wind pressure) and stack-driven ventilation (temperature different). The superiority of natural ventilation mainly manifests itself in three aspects:

1. Energy Efficiency 

2. Thermal Comfort

3. Indoor Air Quality

Innovative openings within building design have been shown to significantly enhance natural ventilation performance, thereby maximizing its efficacy. Assessing the potential and impact of natural ventilation offers robust evidence for designers and owners as they consider the feasibility of utilizing natural ventilation. 

Natural ventilation can provide a high rate of airflow to maintain good indoor air quality and thermal comfort. A study done by (Zoure & Genovese, 2022) demonstrated that natural ventilation in an office was the most effective passive cooling technique, helping to reduce the annual discomfort hours by 40% and the annual energy consumption by 30%. Additionally, significant CO2 emissions are avoided using the proposed designs. Avoidance of CO2 emission will significantly reduce indoor air pollution thus improving the indoor air quality in the building.  Compared to Single Sided Ventilation (SSV), Cross Ventilation (CV) offers higher ventilation rates, improved indoor air quality, and maximum cooling capacity. This is due to the larger pressure difference between different facades, which eliminates the short-circuiting effect observed in SSV, resulting in more efficient removal of indoor contaminants. The airflow characteristic of CV (ventilation rate) was of great importance since it can largely influence both indoor contaminant removal efficiency and thermal comfort. Previous research also investigated two indoor comfort components –thermal and air quality and how these components become correlating factors toward human comfort and human health. (Pigliautile et al., 2019; Pistore, Cappelletti, & Romagnoni, 2019) 

Therefore, the implementation of bioclimatic design strategies is essential to reduce carbon emissions and other effects of climate change. Current building design, standards and practices must transform, but without compromising the inhabitants’ comfort and health. The Uniform Building By-Laws (UBBL) – the mandatory building regulations in Malaysia, especially the clauses 39 that regulate the sizes of openings, have not been reviewed and further researched in accordance with the local climate conditions. Although current building regulations, standards and green rating tools have proposed many natural ventilation strategies in Malaysia, the adaptation of bioclimatic design strategies that is responsive toward the current and future climatic condition has not been fully acknowledged. At the same time, they are not able to address the required improvements in occupants’ comfort and health as well as the reduction of carbon emissions. These design strategies are an efficient architectural approach to improve thermal comfort, occupants' health, and reduce buildings' carbon footprint. 

In conclusion, the recommendations of bioclimatic design strategies can act as a reference for designing buildings that shall promote sustainable built environments as per United Nations Sustainable Development Goal number 11 (Sustainable cities and communities).(Choudhury & Chettry, 2023) Bioclimatic design is not just a set of techniques; it's a philosophy that respects the local climate and prioritizes human health and well-being. By employing these strategies, architects and designers can create buildings that breathe easy in the heat, fostering a healthy and comfortable living environment for all. under the hot and humid sun.