First and second order simplified models for the performance evaluation of low temperature activated desiccant wheels

Abstract

Hybrid systems with a desiccant wheel, DW, are an alternative to heating, ventilation and air conditioning, HVAC, commonly used systems for dehumidification and humidity control in rooms with high latent loads. Currently, the experimental methodology used to study the behaviour of a DW requires a high number of tests. The aim of this study is to obtain a DW empirical model which accurately represents the behaviour of a DW activated at low temperature, values below 60 °C, by conducting a reduced number of experimental tests. For this study, the statistical Design of Experiments technique, DOE, is used. The proposed models can be used to predict the influence of the inlet process air and inlet regeneration air, on the air process outlet temperature and humidity ratio. The accuracy obtained of the experimental models is more than acceptable, with R2 values greater than 97.4% for outlet temperature and 95.1% for outlet humidity ratio. The first order model was considered to be a good option due to the balance between accuracy and the low number of experimental tests required. However, the second order model allowed a deeper understanding of the behaviour of the air outlet conditions in the DW.