Gilberts develops simple approach to delivering ventilation requirements
Gilberts of Blackpool has developed an approach to delivering effective, compliant ventilation of multi-occupancy rooms that is simple to install. Mistrale Fusion is a stand-alone unit that is installed through a wall and protrudes into the room; it does not require additional ductwork or plant. Its internal fan costs less than £5 a year to run.
Roy Jones, the company’s technical director, explains, ‘In effect it provides a hybrid natural-ventilation solution, predominantly using natural buoyancy, with an ultra-low-power fan to gently blend the air and recycle internal warm air without wasting its ambient heat. It is completely stand-alone. In theory, you don’t even need to open windows to maintain a fresh, comfortable, healthy internal environment. ’Installed through an external facade or window, Mistrale MFS mixes internal and external air to ventilate the internal space. Mixing dampers in the unit modulate airflow to allow the new, fresh air to mix with the warm exhaust air — thus extracting its heat without the need for an exchanger.
The integrated low-energy fan energise to blend the internal air, ensuring an even airflow, with control over temperature and CO2 levels within.
The terminal opens in normal mode at around 20°C, although this preset can be adjusted as required. In summer mode, the fan provides additional boost — up to 250 l/s with 100% fresh external air to maintain the required internal temperature, despite the external air being warmer, and also to provide an effective night-cooling strategy.
Just two MFS128 terminal units are needed for a standard 32-person classroom, providing the 8 l/s/person of fresh air required by Department of Education Building Bulletin BB101 and PBSP guidelines.
As the fan provides only occasional support, Gilberts calculates that it uses just 34 kWh of electricity a year.
Operational noise is less than 30 dB(A) for a single unit, and it has been engineered to absorb external noise to keep within the classroom criteria required by BB93. Gilberts’ tests showed that external noise of over 60dB(A) was reduced to 33 dB(A) at full operation.
Air leakage is less than 5 m3/h/m2, and U value is 1 W/m2/K.