FILTER MEDIA: LET'S CLARIFY!
From buildings (hospitals, industries, schools, offices, shopping centres, supermarkets...) to the kitchens where the chef and his collaborators prepare delicious dishes at first sight they’re environments which seem very different from each other but are united by the need to ensure optimal comfort for all those who spend time inside them.
In this context, air conditioning plays a very important role. In fact, it can be a factor capable of influencing the quality and well-being of people, helping to determine their success. To achieve living comfort must be a fundamental objective when designing the air conditioning system. A design that must absolutely take into account some key factors, such as thermo-hygrometric well-being (that particular sensation in which people are at ease and feel neither hot nor cold), acoustic well-being and indoor air quality.
What are the key elements of a good system?
When designing an air conditioning system, maximum attention must be paid to its energy efficiency, its filtration efficiency (high and constant IAQ objective) and its management costs which include ordinary and eventually extraordinary maintenance.
Numerous studies conducted at an international level state that the component of air conditioning systems that has the greatest impact from the point of view of energy and maintenance costs is the filter media.
The choice of a correct filter media represents a central aspect in the design of air conditioning systems.
What are the most popular filter media?
As we have seen, the choice of filter media requires very careful analysis before proceeding with its implementation.
Among the filter media available on the market, below are the most common: soft or rigid bag filter and absolute filter.
BAG FILTER
The best-known filter media in the filtration market and the most used within air treatment systems (AHUs & ROOFTOPs).
Soft Pocket Filters are filter media for air purification and are made up of a variable series of filter pockets made of polyester or glass microfibre, fixed to a frame.
They are often used as a pre-filter for higher efficiency rigid pocket filters or absolute filters (HEPA).
Bag filters with the same geometric characteristics and efficiency class may differ in solid particulate accumulation capacity and energy performance.
ABSOLUTE FILTER
The absolute filter is the best known in the filtration market for its use within sterile air conditioning systems specific for the healthcare-hospital or industrial sectors.
The category of absolute filters for AHUs includes HEPA filters (High Efficiency Particulate Air Filter), i.e. air filters with very high efficiency and particulate filtration capacity.
Absolute filters are flat filters made up of a frame in aluminium, galvanized steel or light and robust plastic, and a filter media made of glass microfibre paper pleated at different heights and with a special system that allows for optimal spacing of the folds.
What alternative?
THE ACTIVE ELECTROSTATIC FILTER
Despite being a filtration technology born at the beginning of the twentieth century, the active electrostatic filter still represents a niche in the air treatment market.
In recent years during the COVID-19 epidemic, the exorbitant increase in energy costs and the increase in sensitivity towards green topics (reduction of waste production and reduction of CO2) is becoming increasingly popular on the market.
The active electrostatic filter is made of aluminum and inside the structure it is made up of two fields: ionization field and collection field.
The pollutant first encounters the ionization field made up of wires that positively charge the particles and then meets the collection field made up of plates, some with the same charge as the wires, others with the opposite charge. The dusty pollutant settles on the plates while viruses and bacteria are neutralized by the electrostatic charge; unlike pocket filters or absolute filters which simply capture them. Active electrostatic filters can be implemented within air treatment systems to replace classic bag filters. In some cases they can also replace absolute filters (to study and evaluate feasibility).
The main advantages given by the implementation of active electrostatic filters are:
1) High and constant filtration efficiency
2) Low and constant pressure drops (energy savings estimated at 30% per year)
3) Significant reduction in system management costs (no replacement, no disposal)
4) Simple maintenance (annual filter washing in standard applications)
Why is Expansion Electronic's FE SYSTEM active electrostatic filtration technology unique in the market?
1) Over 40 years of history in the active electrostatic filtration market
2) High and constant efficiency over time certified by third-party laboratories
3) Inertization of bacteria by intervening on the RNA chain (it does not simply capture them like other filters)
4) Porcelain insulators (longer-lasting, resistant and better than plastic ones because they do not absorb pollutants)
5) Tungsten ionization wires (stronger material)
6) Electrical safety certified by UL867 (specific American regulation)
7) Electronics on board of each filter which allows the multipolar connection between one filter and another. Each filter works as if it were a separate machine. If a filter in the machine does not work, all the other filters continue to work (no machine downtime).
8) Standardized dimensions (the same as the pocket filters that make FE SYSTEM adaptable to the most varied applications, in particular in retrofit and energy requalification projects)
9) Initial pressure drops with a clean filter are approximately 62Pa and remain unchanged beyond 600g of captured dust. This does not happen with traditional bag filters or with absolute filters which start with higher pressure drops already at a clean filter!
10) Simple maintenance: the filter must be immersed in water and detergent for 5-7 minutes and then rinsed with a high pressure washer at a maximum of 60 bar.
The filter must be reinstalled in the machine when completely dry.
The electronics on board each filter must not be removed during washing phases because they are completely resined (waterproof).
