Delving into Climate Conditions, Part 1

Tracing back to grade school geography and social science classes —this post intends to focus on how climate plays a key role in shaping architecture and the built environment.

Identical to the primitive huts, architecture today still fundamentally serves to shelter, protect, and provide comfort for its occupants. In contemporary settings, however, there is a growing concern about climate change and how humans are rapidly and adversely impacting the Earth. As a result, resource efficiency becomes another important criterion for architects to consider when designing their buildings with deliberate decisions.

Measuring the site conditions:

To effectively comply with the previously stated criteria and substantially increase architectural performance for its occupants and the environment, the first step is to first evaluate the site’s climate conditions. Each site has a unique climate condition, therefore it is critical to collect data on the site’s condition as follows:

1. Direct & Diffuse Solar Radiation (W/m2)
2. Dry Bulb Temperature (°C)
3. Relative Humidity (%)
4. Wind Speed & Direction (m/s)

These data can be obtained from local weather stations around the world, most of which are predominantly located at airports (e.g. Bangkok, Suvarnabhumi Airport). Each weather file contains 8760 values of each data, collected hourly on an annual basis. These data are usually collected as a typical meteorological year or TMY, which calculates the average values of each month in a year over a 12-years duration and selects the value closest to the means. These available long-term yearly data can also be used to generate a prediction of climate change, which can then be applied to make informed architectural decisions. One question to think about is: How can architects design buildings to respond to the changing climatic conditions, whilst providing comfort and efficiency?

1 — The Sun and the Earth: Solar Radiation

From a macro perspective, understanding the climatic conditions also means recognizing the sun as the source of energy. The Sun has a distance of 150 million kilometers away from the Earth. It measures a diameter of 1.4 million kilometers and has a surface temperature of 5,800 °K. The sun is a gaseous ball with a radiative core that emits electromagnetic waves, typically known as solar radiation. In this electromagnetic radiation spectrum, energy can be emitted to Earth as visible light, thermal heat radiation (infrared), UV, X-ray, or Gamma-ray.

When solar radiation reaches the Earth’s outer atmosphere, the temperature drops from 5,800 °K to approximately 1,755 °K, and then to an average of 288° K (15°C) near the Earth’s surface. The angle opening of the Sun is around 0.5° of the Earth’s atmosphere and has a circumsolar (the flares surrounding the sun) of 5° opening from a person’s eye perspective.

Due to the magnetic field of the solar system, the Earth rotates 365 times around its 23.5° tilted axis to complete an orbit around the sun. This orbit is elliptical, causing variations in the Earth’s distance to the sun at different times of the year (seasons) as it revolves. Because the Earth is also spherical in shape, the distance between the sun and the regions near the equator is also shorter than the distance to the north or south pole. As a result, a longer distance means that more energy is being lost in space, consequently these regions become cooler. Conversely, a shorter distance, like the equator, then means that it is hotter in the regions.

Solar radiation may also vary due to the Earth’s axial tilt — changing the incoming solar radiation angle. Close to the equator, incoming solar radiation is directly emitted at close to 90° angle, hence concentrated in its energy. While at a lower elevation sun angle, incoming solar radiation is more distributed on the Earth’s surface, thus less hot. Overall, it is very crucial to know the location of the given site and its climate conditions since they will differ from one location to another.

Utilizing ClimateStudio, I’ve compared multiple weather stations around the world to see the difference in climate across the world. I have also chosen to specifically compare Bangkok and Cambridge to escalate my awareness of the difference in climate conditions I will have to face for the next two years!

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Studies have shown that in regions within the latitudes of 0 to 60 degrees, buildings can receive up to 100% natural daylighting. These regions are also where 95% of the world’s population lives. Hence, it is fundamental to understand the climatic conditions of a project’s site and to make conscious decisions to minimize energy use through passive strategies and increase the building’s performance to its occupants and the environment. These decisions can be based on the building’s orientation, envelopment, aesthetic/functional qualities, and all the underlying systems that control the building’s performance.

References:

The provided information is summarized from the Sustainable Building Design course on edX and other referenced online articles including:

• “How Does the Angle of the Sun’s Rays and Amount of Daylight Vary?” Climate Science Investigations South Florida — Temperature Over Time, Climate Science Investigations (CSI): South Florida, 12 Feb. 2019, www.ces.fau.edu/nasa/module-3/why-does-temperature-vary/angle-of-the-sun.php.
• Kozlowski, Rosann. “What Is the Earth’s Atmosphere Composition & Temperature?” Sciencing, 1 Mar. 2020, sciencing.com/earths-atmosphere-composition-temperature-19463.html.

The content is written for personal purposes. Please leave a comment if you find any errors in the information provided. Thank you!