High-Efficiency Portable Electrostatic Air Cleaner With Insulated Electrodes (January 2007)

Portable air cleaners are becoming increasingly popular in household applications. Many different designs and technologies are currently available, and most cleaners are striving for Energy Star certification that requires certain performance and electrical efficiency levels. One of the most important criteria is electrical efficiency. The appliance has to be at least two CADR/W, where CADR is Clean Air Delivery Rate as measured per ANSI/AHAM AC-1-2002 standard and W is input power of the air cleaner. However, there are only a few serious attempts to significantly improve the efficiency of such devices beyond that required by Energy Star standards. This paper investigates relationships between intensity of the electric field inside the collector assembly of an electrostatic precipitator (ESP) and the effectiveness of the ESP operation. Single-pass collection efficiency and other parameters of the ESP were measured under various conditions and optimized for performance and energy efficiency. This paper describes a new collector assembly design. It allows an increase of the electric field in the collection area of the ESP of more than two times when compared to the electric field in conventional ESP designs. This results in an increase in single pass collection efficiency. Other improvements lead to an extremely efficient design that achieves electrical efficiencies as high as 15 to 20 CADR/W compared to the five CADR/W that only a few of the best models can demonstrate. Testing of the new design confirmed the expected bactericidal effect of the technology. The combination of a strong electric field, plasma of the corona discharge and ozone generated during ESP operation effectively kill the microorganisms. All three components (electric field, plasma and ozone) are created as byproducts of ESP operation and do not require additional energy input. Unique catalytic filters optimized for the design remove the ozone without excessive energy consumption. As a result, this new technology does a better job of removing particles from the air, using less than 30% of the energy of the best rated portable air cleaners and kills bacteria in the air at the same time. The significance of this paper is particularly important for possible industrial and commercial applications where energy savings could be considerably more beneficial than in consumer applications.