Performance comparison between enthalpy recovery wheels and dehumidification wheels

• Compare the performance of enthalpy recovery wheels and dehumidification wheels.
• Theoretical model is set up, and validated by experiment results.
• Effects of substrate properties, air mixing rate and rotation speed are evaluated.
• Cold-heat offset rate is defined to evaluate the performance of dehumidification wheels.
• The calculation of maximum efficiency is provided for enthalpy recovery wheels.

A mathematical model of desiccant wheels is established and validated by experimental results. The different effects of substrate, air mixing, and rotation speed on the performance of enthalpy recovery wheels and dehumidification wheels are analyzed. Substrate with high heat capacity and low heat conductivity is recommended for enthalpy recovery wheels, while substrate with low heat capacity and low heat conductivity is suitable for dehumidification wheels. Air mixing should be considered in evaluating recovery wheels' performance but can be ignored for dehumidification wheels. For recovery wheels without considering air mixing, higher the rotation speed, higher the recovery efficiency; when considering air mixing, the optimal rotation speed is lower than the corresponding rotation speed at a 5% air mixing rate. There also exists an optimal rotation speed to obtain better dehumidification performance for dehumidification wheels. Meanwhile, the reasons behind the discrepancies between recovery wheels and dehumidification wheels are discussed.