Congo Basin Cooling Hut: a Habitat Designed for Existing Inhabitants

The Congo Rainforest and Basin is home to over 10,000 species of plants, 2,000 species of animals, and 75 million people. [1] Not only does it contain incredible biodiversity and nearly 150 distinct ethnic groups, it is crucial for regulating the climate: its swampy forests store 29 billion tons of carbon - approximately equivalent to three years' worth of global greenhouse gas emissions. [2] While this is good for the world, large forests also store something else: heat. [3]

Unfortunately, as one of the world's poorest regions, the Congo Basin's inhabitants do not have access to contemporary cooling technologies. Though not much information has been collected on the residents of the Basin, only 19% of people in the Democratic Republic of Congo (which contains the largest area of the rainforest) have access to electricity. In rural areas, this number decreases to 1%. [4] Due to climate change, deadly heat waves have rippled throughout West Africa - including parts of the west equatorial region the Congo Basin is located in. While deaths in the Congo Basin are less documented, countries in nearby areas have reported over 100 heat related deaths in the span of a few days. [5] The temperature in the Congo Basin is lower than its neighbors (averaging between 20C-30C), but its tropical environment yields a high average humidity of 80%. [6] During heat waves, the Congo Basin is dangerously close to the threshold for survivability, which is 31C at 100% humidity [7]. This threshold is even lower for older populations. As the average global temperature steadily rises [8] and without access to modern amenities, the Congo Basin's inhabitants risk illness and death from high temperatures and humidity.

With this knowledge in mind, I wanted to design a home that not only combats high temperature and humidity, but can be built by those living in the Congo Basin using easily-accessible resources.

Building Materials

Mud

Buckets

Wet sand, found in the cuvette of Congo Basin

Raffia cloth, traditional fabric made from raffia palms

Physical Prototype

Paper

Scissors

Tape

Brainstorming + Modeling Software

Samsung Notes

Fusion 360

To stay safe in high heat and humidity environments, the following are important [9]:

• Stay in a cool area
• Consume liquids
• Minimize physical labor

I knew I wanted to design a habitat that could help its inhabitants fulfill those requirements, but it is also crucial to consider who the habitat is being designed for. For this project, I chose to focus on the Efé people.

The Efé are an indigenous group living in the Congo Basin, and they occupy the most land in the Democratic Republic of Congo's part of the rainforest. The Efé are categorized as African Pygmies, who are known for their smaller statues. Males have an average height of 4'8''; women have an average height of 4'6''. [10] They are a foraging society, collecting foods like honey, berries, and fish. In addition to collecting their own food, they trade with the Lese - a neighboring group - for crops. They live in leaf huts, which are simple huts made from gathered branches and leaves. [11] These huts are typically temporary, as deforestation has caused the Efé to move more often. Deforestation has also made it more difficult to catch game. [12]

After doing research, I added a few goals to keep in mind throughout the project:

• Habitat is small, temporary, and easy to build
• Design retains elements of Efé architecture
• Habitat contains an efficient food preservation system

First Objective: Stay in a Cool Area

A common home in parts of rural Africa, including in the Congo Basin, are mud huts. These huts are made from simple materials and only take a few weeks to build. They last several years and can stay resilient even in wetter environments. [13] Additionally, the pores in mud houses trap moisture, keeping them cool during the summer. [14] Because of these benefits, I decided that the main material for the habitat should be mud.

Because few people have access to electricity in the Congo Basin, I focused on passive cooling technologies. One form of simple, passive ventilation are ridged roofs:

Ridged roofs take advantage of heat convection: the tendency for hot air to rise. As hot air naturally rises out of the roof, fresh air rushes in to replace what left. [15] This cools down an area without the need for powered fans.

I also want to retain elements of the leaf huts that the Efé already live in, as the leaves are an effective way to provide shade. With these ideas, I came up with this structure:

This design combines the traditional leaf hut with modern passive roofing ventilation and cooler mud huts.

Second Objective: Consume Liquids

Initially, I thought about collecting rainwater from the roof for consumption - but I also wanted to collect water for an evaporative cooling system, like this one:

Evaporative cooling takes advantage of the natural energy transfer that happens during evaporation. Highest energy particles are released during the process, thus cooling the environment. [16]

I liked the simplicity of evaporative cooling, but I had to work around the fact there would be no fan. I realized I could use the air coming through the windows of the habitat as hot air entering the room. While the air coming in would be cooler than the air leaving the habitat, it would still be relatively warm given the environment. This hot air would then need to pass through a wet evaporative pad, so I decided to add a ring around the habitat that collected and fed water to evaporative pads hung in front of the windows. When researching cloths for these pads, I found that raffia cloth made from raffia palms is common in the Democratic Republic of Congo. The cloth is considered hydroscopic, which means it is more absorbent than usual. [17] Because of its accessibility and absorbency, I chose to use raffia cloth. This new system doubled as a two-in-one shade: there was shade from the ring when standing outside the house, and the cloth was blocking the sunlight from entering the house. Since I was already using a ring for evaporative cooling, I added another ring around the existing one for drinking water. The water from the outer ring is fed into a bucket.

Water dripping from the evaporative cloths can be collected into an evaporative cooling chamber rather than a water reservoir, which I will explain in the next objective.

Third Objective: Minimize Physical Labor

For this objective, I knew I wanted to create a food preservation system. For the Efé, most of the day is spent hunting and foraging for goods. If food could be preserved for a longer period of time, less energy would have to be allocated to hunting. Additionally, game is progressively more difficult to find as deforestation has driven animals away. It is more essential than ever to maintain the food supply. Keeping food fresh also reduces the chance for illness, which is also incredibly important for rural communities.

Researchers have been working on developing evaporative cooling chambers (ECCs) which keep food cool using simple materials:

Just like evaporative cooling air conditioners, ECCs use evaporation to keep remove heat from the system. This has already been implemented in other regions like India and Kenya with success. [18]

The water that drips from the evaporative cooling clothes can drip into a semi-circle ECC, like so:

This design maximizes the use of water to ensure that none is wasted and helps preserve food using a simple cooling mechanism.

I began by putting together the "bottom half" of my habitat. I began with these dimensions for the walls and evaporative cooling chamber:

After extruding, I added on the rings for water collection:

Then I added crucial details such as a water spout for the outer collection ring, three small spouts for the evaporative cooling system's inner ring, and double walls for the ECC:

Once the bottom half was finished, it looked like this:

I then began work on the top half. I started with the same wall dimensions as the bottom half, and added structural supports for the leaf roof:

In place of many leaves, I opted to represent the leaf roof with a hollow semi-sphere:

Here is a view of my top and bottom halves together, before assembling:

And here's a few after assembling, as well as rendered in a forest-like environment:

Because there were no mud textures on Fusion360, I used the Mahogany semi-glossy texture for a muddier feel.

I wanted to use clay, as I felt the texture was the most similar to mud. However, I underestimated how difficult it would be to work with clay, especially when it was rolled out so thin. As a result, my first prototype was a bit... rough:

But any good engineer knows that an important part of the process is to try again!

I decided to turn to a medium I was more familiar with: paper. This time, the prototype looked significantly better.

First, I rolled up a paper ring and cut out holes for the doors and the windows.

Next, I started forming a paper ring to represent the water collection system using a strategically cut strip of paper and some tape.

Once I completed the ring, I made a mini mock up for the double chambered evaporative cooling chamber. The darker parts represent the sand between the mud walls.

I put those components together, and began work on the top half.

For the top half, I rolled up another strip of paper and added supports for the leaf roof.

I then drew and cut out leaves for the roof.

Finally, I attached the leaves to the roof structure, leaving open gaps around the rim of the circle for passive ventilation. This was my finished structure:

What if extreme environment habitats embraced their unique surroundings to enhance human well-being?

The Congo Basin is essential to maintaining global temperatures. Unfortunately, populations that live within are moving out as a result of the extreme conditions - or even directly contributing to deforestation in order to make a wage to survive. [10] If life in the Congo Basin could be more practical, we could encourage the preservation of its environment and the people living in it. Members of the Baka group wrote a plea to the European Commission:

The forest is our home. We rely on the forest to live… But you people have stolen our forest. What are we going to do? How will we survive? We don’t understand why you don’t come to us for our advice and our guidance about how to protect our forest. Haven’t you thought of that? If the forest is so beautiful, it’s because we are here! [19]

In order to protect our world from alarming climate change, we must protect our forests. And in order to protect our forests, we must also protect the inhabitants that have cared for it. Embracing this extreme environment is an opportunity for considering policies that prioritize conservation for our future - and also an opportunity for embracing community resilience worldwide.

What did you learn through this process that you could apply to addressing a problem of the built environment in your own community?

Because my design focused on vernacular architecture and passive solutions, I learned about many ways that architecture can be more sustainable and available. Often, we look to new technologies for solutions, but we also must consider tradition in our creations. Modern day architects have started looking towards raw-earth construction for their own works. Materials like mud, bamboo, and straw are both accessible and resilient materials. As architect Anne Heringer points out, "Mud is a very inclusive material; poor and rich can build with it." [14] It's easy to be caught up in complicated designs, but it's important to remember that there is beauty in simplicity.

As a beginner in CAD, I found this project to be an exciting challenge. I loved researching and learning about architecture, ventilation, and the Efé people. Reading about the struggles of those in the Congo Basin fueled a desire to do something, and I hope I can contribute a greater impact to these causes as an engineer in the future. I have a deeper appreciation for those who work on buildings and save lives with their innovative solutions. Doing this project was both inspiring and galvanizing. From the bottom of my heart, thank you for this incredible opportunity!

Signing off,

Kelly W.

1: https://www.worldwildlife.org/places/congo-basin

2: https://www.unep.org/news-and-stories/story/critical-ecosystems-congo-basin-peatlands#:~:text=The%20peat%20swamp%20forest%20of,of%20carbon%20dioxide%20a%20year%20.

3: https://www.sciencedaily.com/releases/2010/01/100121141112.htm#:~:text=Forests%20can%20trap%20heat%20as,override%20those%20of%20heat%20retention.

4: https://www.trade.gov/country-commercial-guides/democratic-republic-congo-energy#:~:text=Despite%20millions%20of%20dollars%20of,seeking%20to%20power%20their%20facilities.

5: https://www.bbc.com/news/science-environment-68835575

6: https://www.britannica.com/place/Republic-of-the-Congo/Climate

7: https://www.psu.edu/news/research/story/humans-cant-endure-temperatures-and-humidities-high-previously-thought/

8: https://earthobservatory.nasa.gov/world-of-change/global-temperatures

9: https://www.betterhealth.vic.gov.au/health/healthyliving/how-to-cope-and-stay-safe-in-extreme-heat

10: https://www.101lasttribes.com/tribes/efe.html

11: https://www.culturalsurvival.org/publications/cultural-survival-quarterly/forest-foragers-day-life-efe-pygmies-democratic-republic

12: https://www.wrm.org.uy/bulletin-articles/drc-efe-pygmies-deprived-of-their-homeland-and-their-livelihood

13: https://www.planetcustodian.com/mud-house-pros-and-cons/27997/#google_vignette

14: https://www.bbc.com/future/article/20220705-the-sustainable-cities-made-from-mud

15: https://conceptgroupllc.com/glossary/what-is-convective-heat-transfer/#:~:text=Convection%20is%20the%20process%20of,leads%20to%20a%20cyclical%20effect.

16: https://portacool.com/how-does-evaporative-cooling-work/

17: https://www.tis-gdv.de/tis_e/ware/fasern/raffia/raffia-htm/#:~:text=Raffia%20behaves%20strongly%20hygroscopically%20(hygroscopicity,and%20mold%20may%20cause%20depreciation.

18: https://agrilinks.org/post/increasing-access-fresh-fruit-and-vegetables-forced-air-evaporative-cooling-chamber

19: https://survivalinternational.org/news/12204