Effect of rotation speed of a rotary thermal wheel on ventilation supply rates of wind tower system

This study explores the integration of a rotary thermal wheel into a wind tower system, specifically the effect of the rotation speed on the ventilation rate and heat recovery. Wind towers are capable of supplying recommended levels of supply air under a range of external conditions, integrating a rotary thermal wheel will cause a reduction in the air supply rates due to the blockage created by the wheel. Using Computational Fluid Dynamics (CFD) analysis, the air supply rate and heat transfer of the rotary thermal wheel have been calculated for a range of rotation speeds between 0 rpm-500 rpm. The recommended air supply rate of 8l/s/p is attained up to a rotation speed of 50 rpm; beyond this rotation speed the air supply rate is too low. The maximum temperature recovered across the rotary thermal wheel is measured as 1.77°C at a rotation speed of 20 rpm. Using the two results gained from the analysis, an optimum operating range of the rotary thermal wheel can be determined between 5 rpm and 20 rpm. The technology presented here is subject to an international patent application (PCT/GB2014/052513).