Natural-ventilation partnership delivers low-energy heating and cooling
Passivent and Rehau have worked together to develop a low-energy cooling solution for the commercial market. It can also pre-heat fresh air on cold days in the Winter (as illustrated]. The system combines Passivent’s passive stack natural ventilation with Rehau’s Awadukt Thermo ground-to-air heat exchanger. It is particularly appropriate for buildings with deep floor plans and/or restricted facades.
A Rehau ground-to-air heat exchanger draws fresh air into the building and uses the steady temperature of the ground between 7 and 12°C to preheat or precool this incoming air, relying on Passivent extracts to ensure background ventilation in line with regulatory requirements. In commercial buildings a COP of 20 is realistic and up to 50 in domestic buildings.
The system is in use at Carclaze School in St Austell, Devon, which has achieved a BREEAM ‘Excellent’ rating. This 2-storey school is set into a sloping site, limiting available facades. Ventilation for the entire school is integrated into 18 zones for temperature and CO2 control. Air is monitored and flow rates adjusted as required by Passivent’s iC6000 controller.