Bangkok residential project : A contemporary of a timber construction
Project Description:
Bangkok is one of the most dense cities in the world with high temperature and humidity according to the tropical climate. Almost 30 percent of the housing energy consumption cost from air conditioning. In order to reduce household cost and carbon emissions, the design of our project, Bangkok residential building, proposes to use a passive cooling system as a main strategy with Carbon neutral based materials. From research of Bangkok climatic issues, we have extracted the principals of Thai vernacular architecture as the design involves a passive cooling system, and adapt to our project strategies such as incline roof for heat circulation, ground floor openings for cross ventilation and avoid flooding problems. To reduce heat temperature of interior space, Bangkok Residential Building is proposed with the Box-in-Box concept that includes interior façade and exterior shell. Where the zone between two facades is used as a buffer area to cool down the air before entering to the building. The project consists of 2 strategies of design related to the environmental data including forming optimization based on solar radiation and comfort temperature, second is the façade openings based on wind pressure analysis, solar radiation optimization, and daylight factor for efficient indoor visibility.
The design of project strategies has reduced 3.3 Degree Celsius according to the simulation results. And the façade openings could provide wind ventilation to create cross ventilation from South East to North West. And also, we have achieved to use Timber as a main structural materials which our goals are to create sustainability in terms of Carbon-neutral construction.
Local Climate : Located in a tropical climate zone and classified as a mostly humid zone. Bangkok has high temperature and humidity variation between seasons with 3 out of 4 quarters are moderate heat stress with more than 32 Degree Celsius recorded, and feel like temperature are 37 Degree Celsius.
Background : The BRB – Bangkok Residential Building consists of 2 strategies of design including form optimization based on solar radiation and comfort temperature, second is the façade openings based on wind pressure analysis with mainly focusing on passive cooling strategies extracted from Thai vernacular based architecture.
Building Data:
Height : 23 m
Stories : 5
Building Function : Residential
Structural Materials : Hybrid Concrete-Timber
Location : Bangkok, Thailand
Geographic position : Latitude 13.765350, Longitude 100.546514
Elevation : +3.5 above ground level
Climate Classification : Tropical, Hot and Humid
Mean Annual Temperature : 32.5 Celsius
Highest Temperature : 37.5 Celsius
Average Dry Bulb of the hottest months (April, May, June) : 35.3 Celsius
Percentage of Comfort time over the year : 13%
Average monthly precipitation : 148 millimeters
Concept
In order to achieve a passive cooling strategy inside the building we proposed a Box in Box concept that integrates a ventilation strategic system. The integration is trying to minimize the use of structural elements in terms of positions and mass volume.
In relation to Thai vernacular architecture, as a role model for passive cooling, the elements of the project will be optimized according to the principle extracted from this system including open ground floor, high slope roof, self-shading, and most importantly Carbon-neutral based materials will be implement for the structure in order to raise the topic of Carbon emission issues.
Carbon-neutral is our main structural material goal. For this project, timber are majorly the main materials for the building structure. The project was analyzed and minimized to get an optimal solution that allows the system including gravity loads, and wind loads to work.
Inner Box Structure
The inner box structure have implemented the diagonal core where the bracing are align across the building to perform as a shear structure against the wind forces.
Outer Box Structure
The outer box structure are connected façade to façade. And also the roof are carried by the outer façade structure with bracing truss connect to the last floor slab.
Façade Structure
With the bracing structure, the diagrid will be further optimized with wind data to find optimal solution for cross ventilation and also the size of the grid will be optimized again according to the solar radiation to have more self shading.
3D MODEL SYSTEM
The project is proposed to use Timber as main materials for structure and construction. As most of the elements are timber, the diagonal method of bracing will be the strategy as it could reduce the amount of solid surface and create openings on the façade which we are trying to have openings.
Within the Box-in-Box concept, the outer facade structure performs as a shell covering the inside box. Meanwhile, the inner box has 4 cores with 3 in timber and one in concrete to support the fire protection issues. Both two layers of facades are connected with horizontal beams which in this simulation works quite well in terms of utilization percentage. Moreover, the facade was designed in a diagrid structure that allows it to be more subdivided according to the leftover values of utilization percentage which beneficially allow us to have more openings for ventilation. It is possible to make a structure completely from timber, with the exception of the fire protection rules for the staircases.
