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An attic fan installed underneath a roof. A powered attic ventilator, or attic fan, is a ventilation fan that regulates the heat level of a building's attic by exhausting hot air. A thermostat is used to automatically turn the fan off and on, while sometimes a manual switch is used. An attic fan can be gable mounted or roof mounted. Additional ...
A roof turbine ventilator, colloquially known as a 'Whirly Bird' is an application of wind driven ventilation. Passive ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems.
Instead of making wind turbine blade reinforcements from pure glass or pure carbon, hybrid designs trade weight for cost. For example, for an 8-metre (26 ft) blade, a full replacement by carbon fiber would save 80% of weight but increase costs by 150%, while a 30% replacement would save 50% of weight and increase costs by 90%.
Vestas engineers checked and repaired the wind turbine brake on the morning of 22 February 2008. At the last routine inspection it was noted that the main gear of the turbine was also making unusual noises and a sophisticated endoscopic inspection of the gear was planned, but as result of its high cost it was not undertaken immediately.
Loud or persistent noise increases stress which could then lead to diseases, [175] and wind turbines do generate noise, though at typical setback distances, it is extremely low. For example, at a distance of 300 metres (980 ft) the sound generated may be around 45 dB; however, at a distance of 1.5 km (1 mi), most wind turbines become inaudible.
Contemporary sustainable buildings often make use of the stack effect along with related non-electric techniques like ground coupling, earth sheltering, and evaporative cooling to enhance the passive cooling profile of a building. By carefully designing the building's structure, orientation and ventilation paths, architects can leverage the ...
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The new turbine has better electrical and hydrodynamic characteristics and a 40-year working life. [53] On 6 July 2011, a ship loaded with new parts for the turbines left Saint Petersburg. [54] On 8 July 2011, turbines 3, 4 and 5 were working under full load and turbine 6 was in reserve. [55]