All buildings need to be ventilated, to give the people working within them a healthy, comfortable environment in which to spend time. Ventilation systems have become more efficient and effective in recent years, but there is one system that could beat them all. Natural ventilation uses natural wind power and the buoyancy of air to move it around buildings, instead of relying on energy intensive equipment to move the air.
Some figures show that around 60% less energy is used by naturally ventilated buildings. This is because natural ventilation systems require far less power to run. Cool, fresh air is drawn into buildings at ground level through vents, and open windows in the summer. Hot air rises as it is less dense than colder air, so it actually pulls more cool air in below it. Hot air is expelled at the top of the building when it’s warm outside, or mixed with incoming fresh air to heat it, on colder days. The higher the building, the better this system works, reducing the need for energy consuming heating or cooling devices.
Other aspects of the form of the building will dictate how well the system can work. A building that is too wide will not allow sufficient cool air to be pulled in and moved around the entire space. Attention needs to be paid to the internal space of the building, to allow the best air flow. The fabric of the building can affect the efficiency of a natural ventilation system – dense materials such as wood hold onto heat for longer. The orientation of the building and the direction and strength of prevailing winds affect the efficiency of the system too.
Shading is also key, as it can further reduce the cost of the system. Using existing trees around buildings and planting more of them, can help with the cooling of hot buildings. The use of shades on windows inside building can help as well.
We were recently recommended by a firm of Project Managers we’ve worked with for many years, to work on a project to provide natural ventilation for a new serviced office building being designed in Kent. The building is being created to provide small offices for start-up companies that don’t need much space in which to get going. The owner wants to keep the cost of the build low, so that he can pass on those savings through low rent to his tenants. He is also conscious of developing an environmentally friendly building.
Two older buildings on the site already use natural ventilation effectively, so the owner has asked us to design a system for this new office, as it is built. Being brought in at the earliest stage of the project means that we can work closely with the architect, to balance how the building will look and how it will work. We will use our computing modeling system to look at average temperatures for Kent, which will help us to see what is possible in that area. The model will show the percentage of time when the building could get too hot, so that we can take into consideration the height and size of the building, the internal spaces and the number of trees that need to be planted around the new building.
Work should start on the site later this year, to be completed early in 2017. We’ll bring you new of the progress in future issues of this newsletter.