New Air Purification Concept for Significant Improvement in Control of Indoor Air Particle Concentration

The ability to control the particle concentration of the indoor air is relatively limited with the existing techniques used in air conditioning systems of buildings. The present methods to reduce the particle concentration of the indoor air are mainly related to the increase of the ventilation rate and/or the use of supply air filters with high collecting efficiency. Both alternatives seem to be unrealistic if an attempt is made to reduce the particle concentration significantly, for example 90%, in an office or school environments or in "semi-clean" industry premises requiring cost-efficient indoor air purification. The particle concentration of the indoor air can be significantly reduced with a novel air purification concept innovated by VTT Technical Research Centre of Finland. The concept can be integrated into existing air conditioning systems without increasing the ventilation rate or without major increase in energy consumption. In several cases the expected reduction of the particle concentration is at least 90%. The precondition is to use electret filters in combination with a special electric charging system for the filtration of the supply air, and air diffusers provided with effective filtration for the filtration of the indoor air.