The reality of climate change in the UK is being felt in force, from extreme heat and record-breaking temperatures to increasingly frequent flooding events. Building design must change in response, including ventilation. For specifiers, it’s a balancing act between delivering greater energy efficiency and smaller carbon footprints, and creating comfortable spaces equipped to handle heat, cold, rain and everything in between.
Fortunately, automated natural ventilation offers a potential way forward. In particular, hybrid systems, combining the best of natural and mechanical, can achieve both efficiency and comfort aims. Designed with flexibility in mind, these intelligent systems harness the power of the natural elements, while relying on mechanical ventilation in more extreme weather for high-quality indoor air and comfortable temperatures year-round.
Along with providing a solution in response to the issue of changing climate conditions, hybrid ventilations systems are creating healthier environments and, subsequently, happier building occupants. By using natural forces, such as thermal buoyancy and differences in wind pressure, they ensure a consistent flow of fresh air into indoor spaces while removing stale air. This helps reduce the risk of potential health issues, such as Sick Building Syndrome.
Traditionally thought of as simply manually opening windows, modern passive ventilation systems have come a long way, incorporating smart sensors which monitor and adjust for variables both inside and out, while maximising energy efficiency.
Further, technology exists which put windows and building management systems (BMS) in conversation with each other, helping to optimise setpoints for best performance while complementing the use of energy from other building systems.
Considering that lighting, heating and cooling operating emissions account for nearly a third (28%) of all carbon emissions emitted by building and construction (which is 39%), introducing intelligent HVAC systems seems like a step in the right direction of achieving that all-important Net Zero 2050.
One of the greatest benefits of mixed mode is its versatility. External temperatures, relative humidity and air quality will all affect the potential for using natural ventilation in buildings. Given the number of variables impacting effectiveness, a hybrid approach increases considerably the number of buildings, and places, where natural ventilation can be used.
Let’s look at an example of a hybrid solution to better understand how this might look in context.
Case study: Bloomberg European HQ
Bloomberg’s European HQ in Central London sets the benchmark for large-scale sustainable design, including a hybrid natural ventilation system, with a BREEAM score of 98.5% – the highest design-stage score for a major office development.
Used in the northern building’s atrium, the hybrid system helps reduce the nine-storey building’s energy usage by 35%. Vertical fins, incorporating vents that automatically open and close to control airflow, line the building’s façade, allowing outside air in.
During mid-season periods, the smart natural ventilation system controls heating, cooling and fresh airflow while in summer and winter, the office is mechanically ventilated.
This much is clear: sustainable building design must include an energy efficient approach to ventilation. Public health and decarbonisation are top priorities, and that isn’t going to change any time soon. Intelligent natural and hybrid ventilation will help futureproof the UK’s building stock for years to come, no matter the weather.