Supply Air Filtration Using Electrostatic Secondary-Air Purification

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Solution Overview

Problem

Existing supply air devices struggle to effectively remove indoor air impurities without increasing energy consumption or air flow rates, and conventional filters cause high flow resistance, reducing the efficiency of air purification and heating/cooling.

Innovation Solution

The supply air device employs low-pressure-loss electric particle filters and cell gas filters, which ionize air to enhance particulate and gaseous impurity removal, maintaining air flow and reducing energy consumption by minimizing pressure loss and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional filter mats are used for filtering secondary air flow, then air purification is achieved, but flow resistance increases significantly, reducing secondary air flow and cooling/heating efficiency

Engineering Contradiction:
Improveair purification efficiencyVSAvoidcooling/heating efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the physical and chemical parameters of the filter material by using electrostatically charged fibers instead of conventional mechanical filtration. This allows the filter to achieve high purification efficiency through electrostatic attraction of particles while maintaining high air permeability, thus avoiding the flow resistance problem of conventional filter mats.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical filtration mechanism (physical blocking of particles by filter mat) with an electrostatic mechanism (electrostatic attraction of charged particles to oppositely charged filter fibers). This substitution enables effective particle removal without the high flow resistance characteristic of mechanical filter mats.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If outdoor air flow rate is increased to improve indoor air quality, then impurity content is reduced, but energy consumption for cooling and heating increases

Engineering Contradiction:
Improveindoor air qualityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes impurities from the secondary air flow circulating within the building through the filter integrated in the supply air device. This allows maintaining good indoor air quality by filtering recirculated air rather than requiring continuous intake of large amounts of outdoor air, thereby reducing energy consumption for conditioning outdoor air.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements continuous filtration of the secondary air flow that is constantly recirculated through the supply air device. This continuous purification action maintains indoor air quality without requiring intermittent or high-volume outdoor air intake, optimizing energy efficiency.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If supply air flow rate is increased to improve air purification, then impurity removal is enhanced, but duct size and floor height increase, raising costs

Engineering Contradiction:
Improveair purification effectivenessVSAvoidduct system size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent concentrates the filtration function locally within the supply air device itself, rather than requiring system-wide increases in air flow rates. The filter is positioned at a specific location where it can effectively purify the secondary air flow without affecting the overall duct system dimensions or requiring increased floor heights.

Inventive Principle:
Principle #3Local quality

4Reliability

If conventional filter mats are used, then particle filtration is achieved, but flow resistance reduces secondary air flow too much to have significant purification effect

Engineering Contradiction:
Improveparticle filtrationVSAvoidsecondary air flow rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the filtration mechanism from mechanical blocking to electrostatic attraction, allowing the filter to achieve high particle removal efficiency while maintaining high air flow rates. The electrostatically charged fibers attract and capture particles without creating the flow resistance that would reduce secondary air flow.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution achieves high-efficiency air purification with low energy costs, reducing indoor air impurities by 80% for particles and improving thermal control without disturbing air flow or increasing energy use.

Implementation Method 1

an embodiment is used for particulate impurities, whose function in the separation of fine particles is primarily based on an electric filtering effect

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 2

the filter used is a conventional filter mat which, however, causes a high flow resistance

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 3

For gaseous impurities, a cellular filter is used, which causes a low pressure loss compared with conventionally operated filter arrangements

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

The secondary air induced from the room enters the supply air device via a heat exchanger which enables the cooling or, alternatively, the heating of the air

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 5

a circulating i.e. secondary air flow from the room is induced into the supply air jets

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2140207B1Supply air device and method for purification of air in a supply air device
Publication Date: 2016.06.22 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY
  • EP2140207B1 patent drawingFigure 1~2

AI summary

A supply air device comprising supply air nozzles, through which incoming air is led into a mixing chamber and further into a room so that it induces the circulating or secondary air flow from the room, and an electric particle filter and/or a cell gas filter, through which the circulating or secondary air flow is led.