Improvement on dehumidifier performance using a plastic assisted condenser

Abstract This paper proposed a new design concept for improving daily moisture removal rate and energy-efficiency factor of a dehumidifier. The plastic straws with diameters of 12 mm, 8.0 mm and 6.0 mm are inserted between the evaporator and condenser as an assisted condenser. A total of four cases are experimentally investigated, and the numerical analysis is conducted to further explain the performance improvement mechanism. Compared to the original dehumidifier, the assisted condenser with twelve straws having a diameter of 12 mm can pronouncedly improve the moisture removal rate of the dehumidifier by 6.9–9.2% and 1.2–6.4% at the standard condition and over-loading condition, respectively. By reducing the straw diameter to 8.0 mm, the improvement is reduced and the assisted condenser even reveal deteriorated effect at a high fan speed condition. Yet more pronounced degradation is seen when introducing 8.0 mm straws having two rows with staggered layout. It can be explained from numerical analysis that the pressure drop across the assisted condenser plays an important role. The optimum design depends on the balance between the main airflow, entrained airflow, and the flow resistance of the assisted condenser.