Trombe Walls: Sustainable Architecture Solution

This article explains about Trombe walls, its working principle, advantages of Trombe walls, disadvantages of Trombe walls and other information about Trombe walls.

What Are Trombe Walls?

Trombe Walls absorbs thermal energy from the sun and transfers it to the living space. They are largely equatorial facing walls that have been painted in dark colors to maximize the absorption of sunlight. The glass covers the outside of the walls, leaving an insulating air-gap between the wall and the glass.

Trombe walls uses the concept of indirect gain, where sunlight first strikes a solar energy collection surface in contact with a thermal mass of air, converting the absorbed sunlight into thermal energy (heat) which is then released into the atmosphere. In is transferred to the living space.

People sometimes refer to these walls as mass walls, solar walls, or thermal storage walls. However, they are named after the extensive work of Professor Félix Trombe and architect Jacques Michel, who pioneered the design of passively heated and cooled solar structures.

The design of Trombe walls enables them to trap the sun’s energy between the glass and the wall, creating a natural greenhouse effect. As a result, the air between the glass and the wall heats up, and the heat gradually escapes into the living space. This ensures that the wall can store the sun’s energy and use it to keep the building warm, even when the sun is not shining.

Architects commonly use Trombe walls in buildings that receive a lot of sunlight, and they are a great way to reduce the need for artificial heating, which can be costly and contribute to carbon emissions. These walls are also great for keeping buildings cool in summer, as they can be designed to allow natural ventilation.

Trombe Walls provide an innovative and sustainable solution to passive solar building design. They absorb and store the sun’s energy, reducing energy costs and carbon emissions. Architects can incorporate Trombe Walls into a variety of building types to create sustainable structures.

Working Concept Of Trombe Walls

I have described the working principle of Trombe walls in a simple way.

1. A Trombe wall is usually built on a south-facing wall (in the Northern Hemisphere) or north-facing wall (in the Southern Hemisphere) of a building. This is because the sun is in the southern part of the sky during the winter months, and a south-facing wall will get the most sun exposure.
2. The wall is made up of two layers. The first layer is a large, fixed-pane glass window. The second layer is a thick wall made of brick or masonry. There is a small gap (usually around ¾ inch) between the glass and the wall.
3. During the winter months, when the sun is low in the sky, sunlight enters through the glass and heats up the air trapped between the glass and the wall. The dark-colored brick or masonry absorbs the heat, which is slowly released into the building through radiation.
4. As the air in the room warms up, it rises and creates a natural convection current. This draws colder air from the bottom of the room towards the Trombe wall, which heats it up and releases it back into the room. This cycle continues, gradually warming the entire room.
5. In the summer, when the sun is higher in the sky, the overhang on the Trombe wall blocks most of the sunlight from entering the room. This prevents the room from overheating. The small gap between the glass and the wall also allows for air to circulate, which helps to cool the room.

Advantages Of Trombe Walls

1. Trombe walls can maintain a stable indoor temperature with swings of 10-15°F less than direct-gain systems. This feature makes them ideal for passive solar heating.
2. Trombe walls are an eco-friendly and efficient heating solution, which is why they are widely used. They have a simple design, zero running costs, and can reduce a building’s energy consumption by up to 30%.
3. They can reduce annual heating demand up to 25%.
4. They don’t have any problems with glare, ultraviolet degradation, or nighttime privacy since they are full-height walls.
5. Trombe walls are well-characterized for various design and climate parameters, and their performance can be optimized through simple modifications such as adding insulation boards, curtains, or a ventilation system.
6. They offer more controllable energy delivery to living spaces than direct-gain systems. Energy delivery can be immediate through convection or delayed through conduction and re-radiation.
7. They can help reduce overall labor and material costs since multiple solar energy components can be used for different purposes.
8. They work well with multistory buildings since each floor can benefit from the Trombe wall system.
9. They are useful in commercial buildings with significant internal loads as they do not cause overheating problems during occupied hours.
10. Trombe walls are an environmentally friendly option as they help to reduce CO2 emissions.

Disadvantages Of Trombe Walls

1. The impact of Trombe walls on the overall building design is limited since they are consolidated in one building element and only on the equator-facing facade.
2. The full-height Trombe walls can cause a loss of natural daylight unless windows are introduced.
3. Wall hangings or coverings are not allowed on Trombe walls as they block the radiation emitted from the interior surface of the wall at night.
4. It’s important to ensure that living spaces behind Trombe walls have access to natural daylight to prevent them from becoming claustrophobic.
5. If Trombe walls are constructed with upper and lower vents, the upper vent on the thermal mass can suck heated air from the warmer indoor spaces to the cooler air space between the mass and the glazing (reverse-siphon) at night. Back-draft dampers must be used to avoid this.
6. In regions closer to the equator, it’s necessary to insulate and shade the Trombe wall to minimize overheating during the hot season.
7. Trombe walls are climate-dependent, and external temperature and solar radiation levels have a significant impact on energy savings and CO2 emissions.
8. The system requires user action to operate movable insulation or shutters, often on a daily basis.
9. In regions where the local users are not familiar with the system, it’s important to provide guidance either by modeling a prototype or providing a user-friendly operation manual for the wall during different seasons or days.
10. Trombe walls have a poorer economic performance if solar radiation is low during the heating season.

My Thought

As the world moves towards clean and sustainable energy, Trombay Walls can play an important role in sustainable architecture.

Trombay walls also reduce electricity bills. Another advantage of the Trombe wall is that it can be used to heat off grid homes.