Façades are mediations between indoor environmental comfort for the occupants and exterior climate conditions. It protects its inhabitants from excessive sun radiation, abrasive wind, rain, harsh temperature, and other undesirable weather conditions. Feathers are generally used as a mean for birds to regulate their body temperature and support waterproofing. Similar to the purpose of building façade or envelope, which is to provide a comfortable and conducive indoor environment. Mimicking avian feathers, building façade must strive to achieve optimum indoor environmental quality (IEQ). Many people, particularly in developed countries, spend up to 90% of their time indoors. For people in the working class, this phenomenon is inevitable. With poor IEQ, they are prone to several health risks
This research has several objectives:
Many industries are turning to nature for inspiration for tackling the world’s challenges. Feathers are unique to birds or avian species, and are fundamental to many aspects of a bird’s existence. Avian flight feathers have developed, through evolution, an intricate architecture with multi-functional structures that are essential for flight. Feather is the component structure of the outer layer and flight surfaces of all modern birds, which serves many different purposes.
In architecture, building envelope remains of the most important exterior elements for building functionality. While the façade is an elegant component that helps to define the unique architecture aesthetics of the building, it also has the critical role related to energy performance and interior function of a building. Comparable to building façade, feathers act as a barrier and protect birds from external environment factors. Feathers are generally arranged in a unique pattern to better support insulation, thermoregulation, sensory receptions, and many more.
Building function is designated to be a commercial office, with an open plan layout and a core in the middle. Layout is 30m x 50m, total height is 165m.
Feather tracts on avian species are used as the base for panel arrangement and pattern on the façade.
Two types of panels are generated for this project.
In order to control the overlapping between each panel, grid spacing should be adjusted. This is done in conjunction with the feather clustering input.
Vertical behavior is described as panel movements from its original position; which is vertically parallel to building face, to its maximum position; which is horizontally perpendicular to building face. This behavior is responsible for managing the sun radiation gained from each altitude of sun positions throughout the day. Certain degrees of angles were set, which are are: 15˚, 45˚, 60˚, and 90˚. Minimum degree is defined as the original position of the panel; which was set to 5˚rotation parallel to the building face to allow panels to overlap with each other.
Horizontal behavior is responsible of controlling panel’s rotation from left to right. This panel is used to administer the sun radiation from sun lateral movements from east to west. The degrees of angles which were set for this parameter are: 15˚ and 45˚ to the left; and 15˚ and 45˚ to the right. The maximum degree was set to 45˚, as it is impractical to have the panels at more than 45˚ or nearly perpendicular to the building mass.
Analysis period needed to be determined to gain better analysis accuracy. This is especially crucial for total solar radiation analysis. On the contrary, sun movement does not affect visibility; therefore this parameter was disregarded for the quality views simulation. The type of analysis period which was chosen is a whole year analysis period. For this experiment, the whole year analysis was set at an interval of three months. Moreover, the simulations were performed on equinox period of each month, which falls on the 21st to 23rd. In addition, the simulation time period was set to Jakarta’s business hours (9am to 5pm).
Since the sun constantly moves throughout the year; reducing solar radiation could benefit from dynamic movements of the building façade, where vertical movements are combined with horizontal movements. Dynamic panel movement would enable building occupants to adjust the effects on sun radiation exposure and quality of views to their preference. However, there are tons of possible combinations of panel movements and rotation foreach month. So in regards of time efficiency, only one combination for each month was observed. The combination was derived from the study of the sun path of each month; which then was used to determine the opening area and closing points on each building face for vertical movement. In addition, the horizontal movement was also integrated. This movement orients the panel to either left or right, according to sun movements.
Total solar radiation on bare building mass, without panel installation. Based on the results; the building mass receives the highest amount of total solar radiation in June. During the months of March, June, and September; the sun revolves around the east – west – north areas of the building. On the contrary, in December, the highest solar radiation exposure is on the south face of the building.
Experiment 1: Total solar radiation
The objective of this analysis is to observe the functionality and to gain information as to the amount of total solar radiation reduced by adopting the geometry of avian feathers applied as building façade. The result is represented in gradient of colors from blue to yellow, where blue represents 0 kilowatt/hr or less, and yellow represents ≤14.5 kilowatt hr.
For the purpose of this set of experiment, the closing areas generally tend to beat the bottom of the panel areas where solar radiation exposure is less. Therefore, degrees of angles at the opening areas vary between 15˚, 45˚, 60˚,and 90˚; and the panels gradually close to the minimum stacking degree at 5˚.
According to the results, panel B generally yields better performance, especially at 45˚ and 60˚. The performance of the panel becomes less effective when it is combined with horizontal behavior, especially at 45˚. This trend appears in the months of March, September, and December. However, there are some fluctuations seen in the performance of dynamic movement in June. Vertical movements at 90˚ combined with any horizontal degree shows the poorest performance among the others.
Experiment 2: Quality views
The aim of this analysis is to see whether the application of the building façade would obstruct the quality views for at least 75% of all regularly occupied area. However, a view type needed to be determined for this simulation. A view type is defined as an integer representing the type of view analysis that would be conducted. The integer option chosen in Grasshopper was Horizontal 60 Degree Cone of Vision; which is generally used to study views from interior to outdoors. For the results calculation, the threshold for view type value was set to 50% visibility. Therefore, the view type values which were less than 50% were eliminated. The result is represented in gradient of colors from pink to light blue; where pink represents visibility of less than 8%, and light blue represents visibility of 100%.
Based on the result comparisons, it is necessary to set some boundaries and eliminate movements with poor performance in order to obtain the recommended panel behaviors with optimum results. This time, the balance between total solar radiation reduction and area with quality views generated was explored. According to the observations in the previous chapters, the equilibrium between the two experiments falls under the category of 45˚ and 60˚ of panel vertical behaviors. However, 15˚ vertical behaviors could sometimes be used to further reduce the total solar radiation on certain building faces in certain months, even though it sacrifices the percentage of area with quality views generated.
Compared to the results of previous simulations; the recommended panel behaviors generated much better results in reducing solar radiation, yet providing quality views for regularly occupied area. Overall, both panels reduce more than 50% of total solar radiation in every analysis period month. In conclusion, the performance of panel geometry B shows a better balance between reducing total solar radiation and generating quality views. The radiation reduced in every month is above the 50% threshold; and it is able to provide quality views for more than 75% of all regularly occupied area.
As observed in the recommendation, panel B is the preferred option. Due to the site location and its sun paths, Jakarta is ideal for harvesting sun radiation and turning it into renewable energy. However, Jakarta is a city lacking of the production and use of renewable energy. Therefore, PV panel installation in Jakarta might not be effective due to the length of payback time and expensive installation cost. PV panels with payback time exceeding 20 years might not be the best option.
Lastly, to mimic the coloration in avian feather, specific material needs to be determined. For this experiment, the material which could potentially be used is Rockpanel Chameleon panel façade. With these panels, the color of the façade will never be the same, depending on the angle from which it is viewed and the effect of sunlight. However, application of low-e coating is not present from Rockpanel Chameleon panel façade; if applied, the low-e coated panel façade could ultimately further reduce solar radiation and transmission. Building Research Establishment also granted Rockpanel an Environmental Product Declaration or EPD.
Generally, vertical rotations at 15˚ and 90˚, and horizontal rotations at 45˚ tend to generate poor results in both solar radiation reduction and total area with quality views throughout the year. Therefore, vertical rotations at 45˚ and 60˚and horizontal rotations at 15˚ are more preferable.
Panel A, which mimics feather shape of hummingbirds, delivers better result ingenerating total regularly occupied area with quality views. Panel B, which mimics feather shape of eagles, reduces more total solar radiation.
On average, buildings with environmentally responsive façade reduce 50% or less of total solar radiation. On the contrary, adaptation of avian feather in this experiment is able to reduce around 56% to 58.5% of total annual solar radiation, yet also generating more than 75% of total generally occupied area with quality views.
Panel geometry B is the preferred option due to its optimum and balanced results in these three experiments.
