The buildings are to be placed in such a way which can facilitate cross ventilation. Oblique winds between 30 and 120 degrees to the wall can provide cross-ventilation. Also, vegetation can help in contributing shade and deflection.
Ventilation is one of the important factors to be considered while designing structures in the hot and humid climate. The flow of air helps in providing a direct physiological cooling effect. The buildings are to be placed in such a way which can facilitate cross ventilation. Oblique winds between 30 and 120 degrees to the wall can provide cross-ventilation. Also, vegetation can help in contributing shade and deflection. Furthermore, the attic spaces can also be used in ventilation as it helps in decreasing the solar heating through the roof.
For increasing the cross-ventilation openings can be designed of larger sizes. But if the openings are not correctly shaded, it will result in the direct penetration of solar radiation into the interior of the structure. In case the windows are unshaded, the glass area should be limited to 15% of the area of the facade. Also, shading devices become necessary in such cases. Shading devices are critical for visual and thermal comfort and for minimizing mechanical cooling loads as well. The most effective way of shading can be external shading as it helps in cutting off direct sunlight during the summer season along with allowing sunlight in winter to enter the building. The orientation of the façade should be also considered while designing external shading devices as minimum or no shading is required on the north orientation. Also, external shades on southern orientation should be designed after studying the sun path.
Micro-climate is essential to maintain while designing in the hot and humid climate as striking and heating of building surface can be considerably reduced by designing a proper landscape. It can also act as a buffer for restricting noise, traffic, sun, and heat. The temperature of micro-climate can be reduced around the structure and in the site through the evapotranspiration phenomenon as the shade can be created through landscaping. Additionally, deciduous trees help in providing shade during the summer season as well as provide sunlight during the winter season. Therefore, we can plant such trees on south-western as well as the west side of the structure. Furthermore, evergreen trees when planted on the northwest and north side of the structure can help in providing shade throughout the year.
4. Building form
The form of the building can affect solar access, wind exposure, rate of heat loss or heat gain through the external envelope of the structure as well as airflow pattern around the structure, which will also affect the ventilation. The compactness of the structure can be measured with the help of the ratio of surface area to the volume (S/V). The requirement of artificial lighting also depends on the depth of the building. The lowest S/V ratio is believed to be of circular geometry. Thus, the circular form of the building becomes the most energy-efficient in a hot and humid climate.
5. The orientation of the building
Solar passive design technique puts forth light upon the orientation of the building as it affects the solar radiation, daylight, and wind. In a hot and humid climate, the orientation of the buildings should be along the long axes in the east-west direction. This will eventually place the longest façade in north and south direction along with a short wall facing the east and west direction.
6. Innovative daylighting systems
Light pipes are one of the innovative daylighting techniques which can be considered while designing the hot and humid climate. Light pipes help in transporting or distributing natural as well as artificial light. They also make it possible to transport daylight through thick roofs and attics. It is generally made of glass or plastic.
7. Planning of courtyards
The addition of courtyards at the strategic locations in the building helps in maintaining the microclimate of the structure as due to incident solar radiation in the open to sky enclosed space, the air gets warmer and moves upwards and the cool air from the ground level flows through the openings of the rooms surrounding the courtyard.
8. Room arrangements
The thermal load is related to the orientation of the structure and hence, room on the east side tends to be warm during the morning hours and cool down in the afternoon if it does not have much thermal mass. Whereas, the rooms on the western side are cooler in the morning and tend to heat up in the afternoon hours. Rooms that tend to face north, as well as south, remain cool if provided with proper shading devices. Bedrooms can be designed on the east side of the building as this side remains cool in the evenings, whereas storage areas can be placed on the west side. Also, the kitchen should be placed on the west side as it is mostly used in the morning and afternoon hours. Furthermore, the main rooms can also be located on the east or west side. Rooms like the kitchen where heat occurs should be detached from the main building area but can be connected with the use of a common roof.
The efficient solution for hot and humid climates can be using the double roof. The inner layer of the ceiling can be insulated and provided with a reflective upper surface. The air temperature in the inner surface should be a maximum of 4°C. Air that is discharged through the double roof should pass through the veranda and should not be allowed to enter the living zone.
10. Green Walls
One of the solutions to work wonders in a hot and humid climate is the designing of green walls. It helps in providing protection against the solar radiant heat, reducing the glare, sound absorption, filtering the air, stabilization of the microclimate, humidity regulation effect. But the selection of plant species should be done with care, plants with aggressive root systems should be avoided.