There are now a large variety of wind powered ventilator designs in the marketplace and just as wide a range of performance claims. A lot of the claims exceed that available from similar size mechanically driven axial fans tested to ISO 5801. Clearly impossible.Most performance claims also make no reference to established standards or tests. Edmonds undertook extensive test work using established standards to unequivocally determine the true capability of natural ventilators. For the first time, ISO 5801 has been adapted to assess performance of natural ventilators and results compared with AS/NZ 4740 – at present the world’s only published standard for performance testing of natural ventilators. This ground breaking work established (1) that flow rates determined under both test procedures at nil pressure loss were virtually identical and (2) that pressure performance curves could be developed for natural ventilators but, as expected, vindicated that at average conditions, natural vents will struggle to manage more than 5Pa pressure loss. Even the Edmonds Hurricane 900mm flagship natural ventilator could only exhaust 3,340 m3/hr under average wind speed conditions, stack height of 8m and temperature differential of 10C. Yet no other tested ventilator design using a round base could reach even this level. To view this paper please proceed to the link below.
