This study examined the efficiencies of residential ventilation and furnace fans . The scope included a detailed review of motor and motor control t echnology , fan design issues and an international search of motor / fan combinations of conventional and higher - efficiency . It was found that current residential air handlers are often ten times less efficient than their larger commercial counterparts . Cost effectiveness considerations of ventilation and furnace fans ( the most energy intensive applications ) , showed that dramatic improvement s in efficiency are justifiable .
The momentum balance on a centrifugal fan, supplemented by a complete energy balance for rigorous interpretation of power-pressure interactions, relates these variables to flow rate and fan speed. Non ideal behaviour is modeled by direct mechanical interpretation and by engineering correlation, leading to more general expressions than provided by the fan laws. First attempts to fit these expressions to measured data show promise but reveal limitations of current practice in the data collection and reporting process.
A humidity controlled exhaust fan have been tested during the winter season 1991/2. The test have been carried out in a detached one storey house with a flat roof. The relative humidity (RH) have been measured in the following modes: * natural ventilation only* wall mounted fan, setpoint 70% RH, and natural ventilation * fan in the exhaust duct, setpoint 70% RH.The relative humidity levels have been monitored in the shower room and in the other part of the dwelling. The temperatures have been measured in the exhaust duct and in four places in the dwelling.