Part-load performance of energy wheels: Part 1 -- Wheel speed control

Controlling the performance of HVAC systems and air-to-air energy exchangers, to prevent overheating and overhumidifying of the supply air during part-load operating conditions is discussed in this paper. Equations are developed to facilitate the calculation of the optimal energy exchanger performance and the optimal recirculation air flow rate during part-load operating conditions. If these optimal values are applied, it is possible to simultaneously save energy and improve indoor air quality. Numerical and experimental investigations are applied to investigate the potential of using wheel speed control to control the energy and moisture transfer rates in energy wheels. The results show that, during wheel speed control, a numerical model is necessary to predict the part-load performance because the performance is affected by the operating conditions. The effectiveness decreases as the wheel speed decreases for some operating conditions, while the effectiveness increases as the wheel speed decreases for other operating conditions.