In recent years, viruses have increased, and many developers and owners are paying attention to the healthy design of indoor air environments in buildings. Many customers have also asked me about adding air filters, ranging from the filtration effect to the additional cost. To be honest, this is a relatively professional question.
Taking improving the air filter level as an example, for office/residential/shopping mall/restaurant/hotel/exhibition hall/apartment/hospital/school projects, if you want to improve the filtration level, you need to evaluate the air conditioning system, air volume, wind pressure requirements, and site conditions.
Air filter resistance is key
To help everyone understand, let me give you an example:
Assume that the fan operates at an air volume of 3400m3/h, and the fan efficiency is calculated at 70%. If the pressure difference of the filter increases by 100Pa on average, the fan’s power consumption to overcome the filter resistance and run for one year (8400 hours) is Approximately 1133kwh.
If the pressure difference of the filter is reduced by 10Pa, 113kwh of electricity can be saved every year.
The final resistance is generally one times the initial resistance for air filters.
If you replace an air filter with a higher grade, the initial resistance will not increase much. Suppose a medium-high-efficiency or sub-high-efficiency filter is added to the existing air filter. The initial resistance will be higher in that case, so just increasing the filter’s filtration level is generally recommended.
Energy consumption status of AHU(air handling units)
Heating, ventilation, and air conditioning (HVAC) systems are essential equipment widely used in industrial and commercial fields, and the energy they use is mainly electrical.
Relevant statistics show that the power consumption of HVAC equipment in general office buildings accounts for about 40% of the total power consumption, and the power consumption of HVAC equipment in cleanroom factories accounts for 80% of the total power consumption.
The figure below is the result of the life cycle cost analysis conducted by the European Ventilation Association (EUROVENT) on the air handling unit as the main component in the HVAC system.
The results show that energy costs account for about 80% of the entire AHU life cycle cost, of which about 50% is consumed by fans.
How is the energy consumed?
The fan provides kinetic energy by overcoming the resistance of the main components in the air handling unit (such as humidifiers, condenser tubes, heating coils, air filters, etc.).
In other words, most of the energy the fan provides is consumed by the sum of the resistance of each component.
The air filter’s resistance (pressure difference) accounts for about 50% of the total pressure. Therefore, in HVAC systems, the energy consumption of air filters cannot be ignored.
Analysis of air filter and automobile painting manufacturing costs
The paint shop is recognized as a significant energy consumer among the four major automobile production workshops – the energy consumption ratio of Cherry’s paint shop accounts for about 60% of the entire factory; even the American BMW Manufacturing Co., which is known as the world’s first “green paint shop.” The energy consumption of the paint shop also accounts for 50% of the entire factory.
The spray booth and drying room in the coating workshop are the main equipment that consumes energy, accounting for 42% and 6.8%, respectively, in terms of electricity and 49.7% and 27.3% in heat energy.
The CO2 emissions of the two accounted for 64.8% of the total CO2 emissions.
As competition in the car market intensifies, improving quality and reducing costs are essential to adapt to market competition.
Painting costs account for many controllable costs in vehicle manufacturing costs. Reducing painting manufacturing costs has become a significant focus of manufacturers’ cost control.
Cost Analysis of Paint Shop Air Filters
The European Ventilation Association has also analyzed the life cycle cost of air filters. The LCC here is defined as follows:
LCC = Investment + LCC(Energy) + LCC(Maintenance) + LCC(Disposal)
Investment: Refers to the air filter funds involved in the initial installation of the ventilation system (including filter costs, installation frame, labor costs, etc.)
LCC(Energy): Present value of air filter energy consumption (present cost).
LCC (Maintenance): Air filter maintenance and replacement cost value.
LCC(Disposal): Present value of filter processing cost.
The entire LCC analysis of the air filter shows that the investment cost of the air filter accounts for only 4.5%, the maintenance/replacement cost accounts for 14%, the disposal cost accounts for only 0.5%, and the energy consumption accounts for 81%.
Air filter resistance and energy consumption
The changing trend of the air filter’s resistance (pressure difference) in the air-conditioning box is generally. After using a new filter, the pressure rises slowly at the beginning. The filter captures a large amount of dust as the running time increases. The pressure rises rapidly until it reaches its final pressure.
To overcome the air filter’s increasing resistance, the fan’s power (usually a speed-adjustable fan) will continue growing, and the corresponding energy consumption will increase.
I gave an example at the beginning of the article. If the pressure difference of the filter is reduced by 10Pa, 113kwh of electricity can be saved every year.
The air supply volume of the entire spray painting line (including one intermediate coating line, one color paint line, one varnish line, and a spot repair line) in the car spray paint room is higher than 2,000,000 m3/h.
The total number of two-stage pocket filters required is approximately 1,200 pcs. In this way, every time the filter pressure is reduced by 10Pa, approximately 136,000 kWh of electricity can be saved annually.
Controlling the energy consumption of air filters can provide a new idea and breakthrough for automobile manufacturers to save manufacturing costs.
Air filter energy efficiency indicators
Generally, when people choose an air filter, they mainly focus on its filtration level but ignore its energy consumption.
But even filters with the same filtering level have different characteristic parameters. The current European EN779 standard and the American ASHREA52.2 standard for measuring the filtration performance of air filters for general ventilation are currently used.
The classification of filters only stipulates a range. For example, the F6 filtration level of the EN779 standard means that under the test conditions of 3400m³/h air volume and 450Pa final resistance, the filter’s capture efficiency of 0.4μm aerosol particles is 60 %-80% (counting efficiency) range,
Such an extensive efficiency range provides a lot of room for each filter manufacturer to promote their products, and the initial pressure values of air filters of the same level from different manufacturers vary even more – but this indicator is precisely related to the energy consumption of the air filter.
Summary
Energy costs account for about 80% of the life cycle cost of the air handling unit of the entire HVAC system, about 50% of which is consumed by the fan, and the energy consumption of the air filter accounts for about 50% of the fan energy consumption.
Energy costs account for about 80% of the life cycle cost of the air handling unit of the entire HVAC system, about 50% of which is consumed by the fan, and the energy consumption of the air filter accounts for about 50% of the fan energy consumption.
As a significant energy consumer in automobile factories, the paint shop uses many air handling units and air filters. To significantly reduce the cost of painting manufacturing, choosing suitable air filter products that can ensure air cleanliness in the workplace and save energy has become a breakthrough.
Timely debugging, cleaning, and maintaining filters are also effective energy-saving measures.
