Using a solar air heater to ventilate classrooms during the winter season in New Zealand: a potential alternative solution to assist during COVID 19 outbreaks

Ninety per cent of New Zealand classrooms are naturally ventilated by opening windows. Achieving a suitable ventilation level will rely on teachers. A survey showed that less than half of the teachers opened windows during teaching time. Due to the high occupant density in classrooms and a low natural ventilation rate, it is challenging to provide adequate ventilation during the southern hemisphere winter months (June to September). From 9 am to 3 pm, school hours align well with the optimum solar radiation, providing opportunities for solar ventilation.