Canopy: a Passive Cooling Shelter

This is Canopy-a strucutre designed to keep you cool, even in the harshest temperatures, with almost no eletricty.

The roof features rotating wooden fins connected to a central rod, controlled by a servo motor. These fins adjust throughout the day to block direct sunlight while still allowing airflow, reducing heat gain from above.

The walls are designed based on sun exposure. The South and West walls, which receive the most intense sunlight, are insulated with aluminum and plywood to limit heat transfer. The North side receives minimal direct sunlight and is used as a glass wall for natural lighting and plant integration, while the East side, exposed to mild morning sun, contains the entrance and the air intake system.

The most effective cooling feature is the underground air tunnel. Air is drawn in, passes through a 2-meter underground path where it is cooled by the surrounding soil, and then enters the interior space. A vertical chimney helps remove warm air, creating continuous airflow through the structure.

A physical model was also built and tested using an ESP32 and a DHT11 sensor to monitor temperature and evaluate the system’s performance based on a couple of the core features of the design.

Shapr3D

ESP32

DHT11

The first step in creating Canopy is to construct the main structure that will house all the cooling systems. The base was designed as a square enclosure to provide a balanced interior space while allowing for even airflow distribution.

The structure measures approximately 18 ft by 18 ft and includes a partially underground section to take advantage of the earth’s naturally cooler temperature. The lower portion of the structure is embedded around 5ft below ground level, which helps reduce heat transfer and stabilize interior temperatures.

The walls and floor were assembled using sturdy materials to create a sealed interior space, while leaving designated openings for the air tunnel and chimney systems that will be added in later steps.

To reduce incoming air temperature, an underground air tunnel was added to the structure. The tunnel extends approximately 2 meters from the exterior into the interior space.

Air entering the system travels through this tunnel before reaching the room. Because the surrounding soil remains cooler than the surface temperature, heat is transferred away from the air as it moves underground. This results in cooler air entering the structure.

The tunnel was positioned on the East side of the structure, where sunlight is less intense, helping maintain lower intake temperatures. The entrance was left open to allow airflow, while the interior end connects directly into the main space.

This system serves as the primary cooling mechanism by harnessing the ground's natural thermal properties.

To create continuous airflow, a vertical chimney system was installed along one of the walls. The chimney begins near the top of the interior space, where warm air naturally rises, and extends upward along the exterior of the structure.

As air inside the structure heats up, it rises and exits through the chimney. This upward movement creates a pressure difference that pulls cooler air in through the underground tunnel, forming a continuous airflow cycle.

A free-spinning fan was added at the top so that the air spins it and generates electricity to power the servo.

The chimney was extended above the roofline to strengthen this effect. Its placement on a sun-exposed wall allows it to absorb heat, further increasing the upward movement of air.

This process, known as the stack effect, is essential for maintaining passive ventilation throughout the structure.

The roof of the structure was designed with adjustable wooden fins to reduce heat gain from direct sunlight. These fins are mounted on a central rotating rod and can tilt to different angles throughout the day.

A servo motor is used to control the rotation of the fins, allowing them to follow the movement of the sun. By adjusting their angle, the fins block direct sunlight during peak hours while still allowing indirect light and airflow to pass through.

This dynamic shading system significantly reduces the amount of solar heat entering the structure, especially during midday and afternoon hours when the sun is strongest.

At the same time, the gaps between the fins allow hot air to rise and escape, supporting the overall airflow system.

The walls of the structure were designed based on sun exposure throughout the day. The South and West walls receive the most direct sunlight, so they were insulated using aluminum and plywood to reduce heat transfer into the interior space.

The North wall, which receives minimal direct sunlight, was designed with a glass surface to allow natural light into the structure while maintaining a cooler temperature. This side also includes decorative plant elements to improve the interior environment.

The East wall, exposed to mild morning sunlight, was used for the main entrance and the air intake system connected to the underground tunnel.

By designing each wall differently based on solar exposure, the structure minimizes heat gain while maintaining functionality and natural lighting.

This step shows the airflow and exactly how the room is cooled. The blue arrows indicate cool air, and the red arrows indicate warm air.

For this step, I created my model. I started by using my ESP32 and DHT11. Next, I configured them and used Arduino IDE to write my code. It syncs the data to ThingSpeak, using WiFi to send the temperatures. The model I made used a small 2 ft by 1 ft black container. I did 2 tests-1 with the cooling system and one without. The one with the cooling system used insulation; I taped 8x11 paper to the sides. The white paper would also help to reflect some of the heat from the walls and back into the air. Next, I added the shade. The shade was a piece of thick cardstock that I placed over the box. I also taped aluminum foil to the top of the cardstock for additional reflection.

Note: The first picture is the test I did with no cooling system, the second picture is with the cooling system.

The results of my test were as expected-the test I did with the cooling system was around 5º degrees cooler on average-and that was with just 2 systems for cooling.

Canopy is designed not just to cool a space, but to improve overall comfort and well-being. High temperatures can lead to heat stress, fatigue, and reduced focus, especially in areas without access to air conditioning. By lowering interior temperatures using passive systems, this shelter creates a more comfortable and stable environment.

The combination of shading, insulation, and natural airflow helps reduce heat buildup and maintain a cooler interior without relying on large amounts of energy. This makes the design especially useful in regions where electricity is limited or expensive.

In addition to physical comfort, the space is designed to feel more calming and natural. The use of indirect lighting, airflow, and plant integration contributes to a more relaxing environment, which can support mental well-being.

By using simple, efficient design strategies, Canopy demonstrates how thoughtful engineering can address real-world challenges. It provides a practical way to reduce heat exposure, improve comfort, and create a healthier living space—showing that even small-scale designs can have a meaningful impact.