Sustainability and environmentally-friendly products have lately come to prominence as part of the increasing human focus on preserving the planet. In the architectural field, green building regulations provide guidance to this demand for sustainable design. Thus, there is an increasing number of buildings applying green building certification all over the world. One of the major components of a building is its façade; thus, it is inevitable that the façade system holds an important role in providing sustainability in the building lifespan, especially regarding the energy consumption required to provide a comfortable indoor environment. As the façade separates the interior and the exterior of the building, it functions as a barrier to the extreme temperature outside. Different climate conditions result in a large range of temperatures, and the façade system must be adjusted accordingly so the comfortable indoor environments can be achieved.
There are four major climate classifications according to the Köppen climate classification , and each climate gives a different range of temperatures that might not be able to be withstood by one façade system. The Singapore green building regulation, Green Mark - Nonresidential Building , suggests green walls (green façade) be used as the façade system on Singapore buildings. In contrast, United State Green Building Council Leadership in Energy and Environmental Design (USGBC LEED) does not have a façade system regulation that determines suitable façade systems on each climate condition, because the United States consists of an indubitably wide range of climate classifications. Therefore, to understand how different climates affect the indoor thermal comfort levels and the energy consumption through these façade systems, five different simulations have been conducted. Solar path and PV potential simulations were performed to understand the solar radiation level and the solar pattern on each climate condition. Meanwhile, heating and cooling load and daylighting simulation were performed to study the efficiency of each façade system based on the heat transfer coefficients, known as U values, and the indoor illumination levels. The heat transfer coefficient of materials, in general, affects the energy consumption on heating and cooling corresponding with the solar radiation level exposed on building surfaces. Proper daylight into the indoor space balances the heating and cooling load and provides a comfortable visual environment. Lastly, thermal sensation simulation provides the key results for the optimal condition of the indoor space when using different façade systems. Thus, three sustainable façade systems and one regular curtain wall system were carefully selected and used on these simulations. The three sustainable façade systems are double skin façade, green façade, and algae panel façade. For the solar radiation level, a temperate climate has the highest level; thus, the PV potential is also high. However, with the algae façade in tropical climates, the heating and cooling load can be optimized and yields the best energy-saving performance. Then, to achieve the best saving on energy, it is also important to investigate the daylight condition. Based on the daylighting simulation results, the algae façade system has the best daylighting illumination level in a tropical climate. In addition, the results show that the even and neutral thermal sensation can be achieved by using an algae façade.
In short, the green façade and algae façade show better performance in sustainability according to the energy efficiency with algae façade for all four-climate conditions on all simulations

Sustainability and environmentally-friendly products have lately come to prominence as part of the increasing human focus on preserving the planet. In the architectural field, green building regulations provide guidance to this demand for sustainable design. Thus, there is an increasing number of buildings applying green building certification all over the world. One of the major components of a building is its façade; thus, it is inevitable that the façade system holds an important role in providing sustainability in the building lifespan, especially regarding the energy consumption required to provide a comfortable indoor environment. As the façade separates the interior and the exterior of the building, it functions as a barrier to the extreme temperature outside. Different climate conditions result in a large range of temperatures, and the façade system must be adjusted accordingly so the comfortable indoor environments can be achieved.
There are four major climate classifications according to the Köppen climate classification , and each climate gives a different range of temperatures that might not be able to be withstood by one façade system. The Singapore green building regulation, Green Mark - Nonresidential Building , suggests green walls (green façade) be used as the façade system on Singapore buildings. In contrast, United State Green Building Council Leadership in Energy and Environmental Design (USGBC LEED) does not have a façade system regulation that determines suitable façade systems on each climate condition, because the United States consists of an indubitably wide range of climate classifications. Therefore, to understand how different climates affect the indoor thermal comfort levels and the energy consumption through these façade systems, five different simulations have been conducted. Solar path and PV potential simulations were performed to understand the solar radiation level and the solar pattern on each climate condition. Meanwhile, heating and cooling load and daylighting simulation were performed to study the efficiency of each façade system based on the heat transfer coefficients, known as U values, and the indoor illumination levels. The heat transfer coefficient of materials, in general, affects the energy consumption on heating and cooling corresponding with the solar radiation level exposed on building surfaces. Proper daylight into the indoor space balances the heating and cooling load and provides a comfortable visual environment. Lastly, thermal sensation simulation provides the key results for the optimal condition of the indoor space when using different façade systems. Thus, three sustainable façade systems and one regular curtain wall system were carefully selected and used on these simulations. The three sustainable façade systems are double skin façade, green façade, and algae panel façade. For the solar radiation level, a temperate climate has the highest level; thus, the PV potential is also high. However, with the algae façade in tropical climates, the heating and cooling load can be optimized and yields the best energy-saving performance. Then, to achieve the best saving on energy, it is also important to investigate the daylight condition. Based on the daylighting simulation results, the algae façade system has the best daylighting illumination level in a tropical climate. In addition, the results show that the even and neutral thermal sensation can be achieved by using an algae façade.
In short, the green façade and algae façade show better performance in sustainability according to the energy efficiency with algae façade for all four-climate conditions on all simulations

ASHRAE Standard 55. Thermal Environmental Conditions for Human Occupancy. American Society of Heating, Refrigerating and Air-Conditioning Engine.
Building and Construction. (2015). Green Mark for Nonresidential Building NRB. Singapore: Green Mark Department Building and Construction. P22.
Curtain Wall Façade System.: https://trimo-group.com/en/trimo/products/facades-and-walls/q-air/system/
Curtain Wall. Retrieve March 18, 2018 from https://www.wbdg.org/guides-specifications/building-envelope-design-guide/fenestration-systems/curtain-walls
Solar Heat Gain Mechanism. Retrieve April 03. From the Australian Window Associationhttp://www.yourhome.gov.au/passive-design/glazing
Double-skin Façade system. Retrieve from: https://iitbuildingscience.wordpress.com/2013/10/10/double-skin-facade
Evolutionary Optimization of Façade Design. P1 – p6. Retrieve April 02, 2018.
Green Building Use Algae-covered walls Façade for Heating. Retrieve from https://www.wfm.co.in/green-building-use-algae-covered-walls-facades-for-heating/
Green Façade Definition. Retrieve March 18, 2018 from http://www.growinggreenguide.org/technical-guide/introduction-to-roofs-walls-and-facades/green-facade-definition/
Heating and Cooling Loads, Retrieve May 16, 2018 from: www.basix.nsw.gov.au/iframe/thermal-help/heating-and-cooling-loads.html
ISO 7730:2005. Ergonomics of the Thermal Environment-Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria. The International Organization of Standardization.
Köppen Climate Classification. Retrieved March 15, 2018 from http://www.thesustainabilitycouncil.org/the-koppen-climate-classification-system/the-cold-climate/
Material Thermal Conductivity. Retrieve May 15, 2018 from hyperphysics.phy-astr.gsu.edu/hbase/Tables/thrcn.html
Recommended Light Levels, Retrieve June 8 2018. From https://www.noao.edu/education/QLTkit/ACTIVITY_Documents/Safety/LightLevels_outdoor+indoor.pdf
Seasonal Performance of Shading. Retrieve from: : https://www.wbdg.org/resources/daylighting Illustration by RNL Design
Shu, L.F., He, G.Q., Zhang S.M., & Bai, Q.A. (2012). Thermal Characteristic and Energy Performance of Double Skin Façade System in the Hot Summer and Cold Winter Zone.
U.S. Green Building Council. (2013). Indoor Environmental Quality. U.S. Green Building Council 2101 L Street, NW Suite 500Washington, DC 20037. LEED
World’s First Algae Bioreactor Façade Nears Completion. Retrieve April 30, 2018 from https://www.archdaily.com/339451/worlds-first-algae-bioreactor-facade-nears-completion
Yunus A. 2011. Fundamentals & Applications Fourth Edition. Ghajar Mc Graw-Hill, Chapter 3 STEADY HEAT CONDUCTION Mehmet Kanoglu University of Gaziantep Copyright The McGraw-Hill Companies, Inc.