Preliminary study of the performance and operating characteristics of a mop-fan air cleaning system for buildings

A theoretical investigation has been made into the performance of a novel mop-fan air cleaning system able to perform self-cleaning while circulating indoor air throughout the building space. The mop fan therefore reduces the need for outdoor fresh air and so energy for heating/cooling the air. The fluid dynamic characteristics of the mop impellers have been simulated using a model developed on the basis of previous test data. Characteristic parameters such as volume flow coefficient CQ, pressure coefficient CΔp and power coefficient CP, are indicated as the functions of rotation speed, mop fibre number and diameter. An optimum working state is recommended for maximum static efficiency. The UV light-photon characteristics of the mop cleaning system have been simulated using a model developed on the radial-diffusion assumption, and the photochemical reaction in the system has been investigated using Langmuir–Hinshelwood kinetic theory. A room self-cleaning process has been analysed, taking into account the effect of pollutant-generating rate and air flow rate on mop reaction efficiency and self-cleaning time. It is concluded that increased mop fibre diameter and quantity, as well as enhanced light source intensity, benefit the dynamic and photochemical performance of the mop cleaning system. Increasing the air flow rate and reducing pollutant-generating rate can significantly shorten the time to achieve a steady-state condition and helps to reduce pollutant concentration in the room.