A novel design of a rotary desiccant system for reduced dehumidification regeneration air temperature

Abstract

A novel design of rotary desiccant wheel has been tested experimentally in a two channel duct with countercurrent flow arrangement. Silica gel coated radial blades extending from the centre of the wheel were arranged at equally spaced intervals in 32-blade and 20-blade configurations. The design was focused on reducing the pressure drop across the device, as well as the regeneration temperature required for desorption of the desiccant compared to 80-120°C temperature currently required. It was envisioned that the increased air volume between radial blades would reduce the pressure drop and the regeneration temperature would be lowered due to the use of silica gel beads as compared to powder coating. The maximum pressure drop across the device was measured as 10.31Pa, significantly lower than current dehumidification systems. The regeneration air temperatures were set between 25°C and 40°C, increasing at 5°C increments. The experiments showed that reduction of the relative humidity of the airstream by up to 67% was possible within this range, whilst the silica gel continued to desorb water molecules, even at regeneration temperatures as low as 25°C. Further investigation with various parameter variables and designs will be undertaken to optimise the rotary desiccant wheel for low pressure drop and low regeneration air temperature.