Modern HVAC systems must handle increasingly demanding air quality requirements, with particulate removal needs ranging from PM2.5 to ultrafine particles below 0.1 microns. Traditional mechanical filtration faces inherent limitations in capturing these smaller particles without creating substantial pressure drops that reduce system efficiency and increase energy consumption.

The fundamental challenge lies in achieving high filtration efficiency for sub-micron particles while maintaining acceptable pressure drops and system performance across varying environmental conditions.

This page brings together solutions from recent research—including external charging precipitators, multi-electrode configurations, temperature-responsive ionization systems, and integrated desiccant technologies. These and other approaches demonstrate how electrostatic filtration can be optimized for practical HVAC applications while addressing both efficiency and energy consumption concerns.

1. Air Conditioner with External Charging Electrostatic Precipitator and Upstream Electrode Configuration

SAMSUNG ELECTRONICS CO LTD, 2025

Air conditioner with an electrostatic precipitator that improves air purification efficiency by utilizing an external charging mechanism. The air conditioner features a housing with a suction panel and a fan, which generates air flow through the suction panel. An electrostatic precipitator is positioned inside the housing with a discharge electrode and an upstream electrode. The upstream electrode creates an electric field between the discharge electrode and the suction panel, allowing ions generated by the discharge electrode to be directed into the suction panel. This external charging mechanism enables the precipitator to charge aerosols in the air outside the housing, improving air purification efficiency compared to traditional internal charging methods.

EP4502479A1-patent-drawing

2. Vehicle Air Conditioning System Air Filter with Downstream Ionizer and Upstream Counter Electrode for Enhanced Electrostatic Particle Separation

MAHLE INTERNATIONAL GMBH, 2025

Air filter device for vehicle air conditioning systems that enhances electrostatic separation of filter elements through a novel ionization and polarization mechanism. The device comprises an ionizer positioned downstream of the filter element, where an electrode generates a corona discharge. An upstream counter electrode, connected to a high-voltage power source, provides an additional electrostatic field. The ionizer and counter electrode are strategically positioned to create an electrostatic field that enhances the separation performance of the filter element, particularly for particles with high electrostatic charges. This approach enables improved filter performance and service life, even in aged filter elements, by leveraging the combined effects of ionization and polarization.

3. Air Filtration System with Advanced Media and Airflow Management for Motor Vehicles

MAHLE INTERNATIONAL GMBH, 2025

A high-performance air filtration system for motor vehicles that provides exceptional air quality and durability through advanced filtration technology. The system incorporates a proprietary combination of advanced filtration media, a high-efficiency filter housing, and a unique airflow management system to achieve superior air quality while maintaining long-term system performance. The system's filtration media includes a combination of high-performance activated carbon, electrostatic precipitants, and advanced nanomaterials, which work together to capture a wide range of airborne pollutants. The filter housing is designed with a unique airflow management system that maintains optimal airflow while minimizing pressure drop, ensuring consistent system performance.

4. Automotive Air Filter with Ionizer and Multi-Electrode Configuration for Enhanced Electrostatic Dust Charging

MAHLE INTERNATIONAL GMBH, 2025

Air filter device for automotive air conditioning systems that improves dust removal efficiency through electrostatic charging. The device incorporates an ionizer with multiple spray electrodes, a counter electrode upstream of the ionizer, and a second electrode downstream of the ionizer. The counter electrode creates an electric field that enhances particle charging and polarization in the filter element, while the second electrode provides a separation barrier. The ionizer generates ions in the air path, which are then directed to the counter electrode, creating an electric field that enhances dust separation. The device's design enables continuous dust removal through electrostatic charging and polarization, even in applications where conventional filter elements struggle to capture fine dust.

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5. Motor Vehicle HVAC System with Integrated Ionizer for Electrostatic Particle Charging in Filters

MAHLE INTERNATIONAL GMBH, 2025

A motor vehicle HVAC system that achieves high filtration efficiency through electrostatically charged particle filters. The system incorporates an ionizer that generates an electric field for particle charging, which restores the original electrostatic properties of the filter material. This ionizer can be integrated into the existing air filtration system, eliminating the need for additional components. The charged filter material enhances its filtration performance by capturing larger particles, while maintaining its original flow characteristics.

6. Vehicle Air Conditioning Air Filter with Integrated Ionizer and Electrostatic Filter Element

MAHLE INTERNATIONAL GMBH, 2025

Air filter device for vehicle air conditioning systems that incorporates an ionizer and electrostatic filter element. The device features a flow path where airflow passes through the ionizer, which generates corona discharge in the airflow. This ionized airflow then passes through the electrostatic filter element, where electrostatic charges are generated. The airflow then continues through the ionizer and filter element, creating an electrostatic field that enables effective electrostatic separation of particles. The ionizer and filter element are connected to a high-voltage power source, with the filter element's surface serving as the counter electrode.

7. Motor Vehicle Air Conditioning System with Upstream Electrostatic Filters in Air Supply Channel

AUDI AG, 2024

Air conditioning system for motor vehicles that utilizes electrostatic filters in the air supply channel upstream of the blower. The system integrates electrostatic filters into the air supply channel before the blower, allowing them to capture airborne contaminants before they reach the blower. This approach enables the use of existing air conditioning units while maintaining high air quality performance.

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8. Compact Air Conditioning System with Integrated Multi-Layer Filter Assembly

厦门呼博仕智能健康科技股份有限公司, 2022

A compact air conditioning system that integrates a filter assembly within the air conditioner itself. The system comprises a casing with integrated filter slots, featuring a primary filter, electrostatic precipitator, and medium-efficiency filter in a layered configuration. The filter assembly is sealed and connected to the fresh air system and temperature/humidity control system. The system achieves improved filtration efficiency while maintaining compactness, with the primary filter providing high efficiency while the electrostatic precipitator and medium-efficiency filter offer additional cleaning capabilities.

9. Electrostatic Air Filter Device with Temperature-Responsive Ionization and Deposition Control

BMW AG, 宝马股份公司, 2022

Electrostatic air filter device for motor vehicles that optimizes operation based on temperature differences. The device incorporates an ionization unit and a deposition unit, with temperature sensors integrated into the filter housing. When the internal and external temperatures deviate significantly, the device activates the ionization unit and maintains it for a period, while deactivating the ionization unit and deposition unit when the temperature difference is less than a predetermined threshold. This temperature-based control strategy enables the device to operate effectively in both fresh air and recirculated air modes, while minimizing wear on the ionization unit.

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10. Cabin Air Filter with Integrated Desiccant-Filled Enclosure for Moisture Removal

BROOKS WILLIAM C, 2022

A cabin air filter that dehumidifies and filters vehicle cabin air to prevent mold and odor buildup. The filter has a dehumidifier component that attracts and removes moisture from air before it flows through the filter. The dehumidifier is a desiccant-filled enclosure around the filter that captures moisture from the air before it enters the filter. This prevents mold and odor buildup in the filter and the HVAC system.

11. Air Purification System with Dual-Mode Electrostatic Precipitator and Ionizer

DORNIER NO LIMITS GMBH, 2022

Air purification system for closed spaces like aircraft cabins and vehicle interiors that simultaneously cleans air and maintains air quality. The system employs an electrostatic precipitator module with an ionizer that generates ozone through electrical discharges. During normal operation, the module separates airborne contaminants from clean air. However, during room cleaning, the module reverses its operation to deliver ozone-rich air against the main flow direction, creating an electrostatic field that enhances the cleaning process. This dual-mode operation enables comprehensive air purification while maintaining a controlled ozone concentration.

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12. Integrated Air Environment System with Air Conditioner, Fresh Air Device, Electrostatic Precipitator, and Air Quality Sensor

SHENZHEN ENVICOOL HEALTH ENVIRONMENT TECHNOLOGY CO LTD, 深圳市英维克健康环境科技有限公司, 2021

Air environment machine that enhances indoor air quality through comprehensive purification and ventilation. The machine integrates an air conditioner, a fresh air device, and an electrostatic precipitator, with an air quality sensor that continuously monitors indoor air quality. The machine employs a primary effect filter with honeycomb-shaped dust suction holes to capture airborne contaminants, while the fresh air device provides a continuous supply of clean air. The electrostatic precipitator captures airborne pathogens and microorganisms. The machine's air quality sensor continuously monitors indoor air quality, enabling real-time adjustments to maintain optimal indoor air quality.

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13. Electrostatic Dust Removal Air Intake Device with Non-Linear Air Inlet Surfaces and Integrated Cleaning Mechanism

佛山市云米电器科技有限公司, Chen Xiaoping, CHEN XIAOPING, 2020

A wide air inlet surface type electrostatic dust removal air intake device that improves air quality by utilizing a unique electrostatic dust removal mechanism with non-linear air inlet surfaces. The device features a main body with an electrostatic dust removal mechanism integrated into the air inlet channel, where the electrostatic precipitator has air inlet surfaces with non-linear edges. This design enables the electrostatic precipitator to effectively capture airborne dust particles while minimizing the generation of electrostatic charges within the air intake system, thereby reducing dust entry into the device and improving user comfort. The device also incorporates a cleaning mechanism that removes accumulated dust from the electrostatic precipitator's surface, ensuring optimal performance and maintaining the device's electrostatic properties.

14. Air Inlet Device with Integrated Electrostatic Dust Removal and Closeable Baffle Mechanisms

佛山市云米电器科技有限公司, Chen Xiaoping, CHEN XIAOPING, 2020

Electrostatic dust removal type air inlet device with improved air quality management. The device comprises a main body, an electrostatic dust removal mechanism, and a closeable baffle mechanism. The electrostatic dust removal mechanism is integrated into the air inlet channel, while the closeable baffle mechanism seals the inlet and prevents dust from entering the device. The electrostatic dust removal mechanism uses electrostatic adsorption to capture airborne particles, while the baffle mechanism ensures dust-free operation. The device incorporates a maintenance cleaning system to remove long-term electrostatic dust accumulation.

15. Automotive Air Conditioner Ventilation System with Integrated Purification Modules and Adjustable Airflow Control

天津宏泰空调净化设备有限责任公司, TIANJIN HONGTAI AIR CONDITIONER PURIFICATION EQUIPMENT CO LTD, 2020

A ventilation and purification system for automotive air conditioners that enhances indoor air quality while maintaining airflow efficiency. The system comprises a ventilation duct with strategically positioned sliding grooves and fixed rods, a fixed fan assembly, and a network of air purification components including a dust filter, electrostatic adsorption module, activated carbon adsorption module, and plasma generator. The system's unique design allows for precise control of airflow and air quality while maintaining the vehicle's airflow path.

16. Electret Filter Material with Nanofiber and Non-Woven Fabric Layers for Enhanced Charge Retention

ZHEJIANG JIAHAI NEW MAT CO LTD, 2019

Electret automotive air conditioner filter material that combines high-performance nanofibers with advanced electrostatic charging for enhanced filtration efficiency. The material comprises a matrix layer of viscose fiber non-woven fabric, a middle layer of electrospun TPU nanofibers, and a bottom layer of polypropylene fiber non-woven fabric. The TPU nanofibers serve as a superfilter layer, while the PP fiber non-woven fabric provides a bottom layer. This sandwich structure enables effective charge retention and ionization, maintaining high filtration performance even under dynamic conditions.

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17. Vehicle Air Conditioner with Dual Parallel Filter Members and Integrated Vibration Motor

HANON SYSTEMS, 2019

Vehicle air conditioner with improved air filtration and reduced noise. The system comprises an air filter installed on the air conditioning case, comprising two filter members in parallel alignment. The filter members are designed with a unique cross-sectional structure that enables frictional contact between them. A vibration motor is integrated into the filter design to create static electricity between the filter members, allowing contaminants to be effectively adsorbed. This configuration enables both static dust collection and reduced air flow resistance, while maintaining the system's ability to operate with minimal power consumption.

18. Air Filter with Tubular Electrostatic Fiber Filter and Integrated Ventilation Path

KIM DONG-KYU, 2019

An air filter for heating and cooling systems that enables efficient dust removal while maintaining air flow. The filter comprises a housing with a tubular body and an electrostatic fiber filter unit formed of a tubular body and an electrostatic fiber filter body. The filter housing features a ventilation path that connects the filter housing opening to the suction unit, enabling dust particles to be captured while maintaining airflow. The electrostatic fiber filter body is formed with a filter support member and filter fiber body, with a separation plate separating the support from the housing. The housing cap supports the electrostatic fiber filter unit, providing a secure mounting system while maintaining airflow.

19. Air Conditioner with Integrated Electrostatic Filter and Ionization System

GD MIDEA AIR-CONDITIONING EQUIPMENT CO LTD, 2019

Air conditioner with electrostatic purification system that incorporates a high-performance electrostatic filter or dust collector in the air intake path. The filter utilizes a proprietary electrostatic material with built-in ionization capabilities to capture airborne contaminants, while the ion generator in the duct produces both positive and negative ions to enhance purification efficiency. The system integrates with the air handling system to provide comprehensive indoor air purification while maintaining efficient airflow.

20. Automobile Air Conditioner with Integrated Electrostatic Precipitator and Layered Soft Filter Element

WUHU DEXIN AUTOMOTIVE PARTS CO LTD, 2018

Automobile air conditioner with electrostatic dust removal through a novel air intake structure that integrates an electrostatic precipitator between the air duct inlet and the soft filter element. The electrostatic precipitator captures airborne dust particles, significantly reducing the need for frequent filter replacements. The soft filter element, comprising activated carbon and fragrance layers, provides effective air filtration while the electrostatic precipitator enhances dust capture. This integrated design enables the air conditioner to maintain optimal cabin air quality while minimizing maintenance requirements.

21. Air Intake Structure with Electrostatic Precipitator and Sequential Filter Layers for Dust Removal

22. Automotive Air Conditioner with Integrated Electrostatic Precipitator and Movable Dust Control Cover

23. Electrostatic Particle Separator with Self-Cleaning Collecting Electrode for Vehicle Ventilation Systems

24. Air Conditioner with Electret Filter Positioned Between Air Inlet and Heat Exchanger

25. Air Conditioner Filter Element with Symmetrically Positioned Ionization Plate and Multi-Layered Filter Plate

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