How does low-resistance HEPA compare with ordinary HEPA in long-term energy consumption?

The word 'low resistance' is often used as a synonym for energy saving in the purchasing process. But there are several layers of variables between these two numbers: how much resistance is lower and how much power can be saved.

Reducing resistance itself does not mean reducing energy consumption. The energy consumption of a fan depends on the operating point at which it operates, and the operating point is determined by both the system resistance and the fan characteristics. To settle this account clearly, we must first align the comparison conditions.

First unify the boundaries of comparison

To compare the energy consumption of two HEPAs, the premise is that they serve the same need.

Items that need to be unified include: efficiency level, overall dimensions, target design air volume, installation method and sealing structure. If two products don't have the same efficiency rating, or are different sizes, there's no point in comparing them—they're not meant for the same location.

Under the premise of the same efficiency level and the same size, let's look at the difference in resistance data. The difference at this time mainly comes from the different designs of filter material structure, pleat density and effective filter area.

Resistance data should be taken at the same air volume

Ask the supplier for the resistance curves of the two products at the target design air volume, rather than just looking at a certain marked value.

There is a non-linear relationship between resistance and air volume, and the resistance difference range is different under different air volumes. Comparing data from just one point may magnify or narrow the actual gap.

After obtaining the resistance curve, combined with the position of the fan in the system, the working points under the two plans are calculated. The difference in working points is the source of the difference in energy consumption. For matching FFU fan filter unit system, the fan is part of the unit, and the working point verification is relatively straightforward; if it is a centralized air supply system, the air duct resistance and end adjustment method must also be taken into consideration.

The fan and control method determine whether to save energy or not.

The same resistance drop has different energy-saving effects under different control methods.

Fixed speed fan : The rotation speed is fixed, and the air volume will increase after the resistance is reduced. The actual energy consumption may not change much, or even be wasted because the air volume exceeds the demand. This type of system must be coordinated with air valve adjustment to convert resistance advantages into energy consumption advantages.

Variable frequency or EC fan : the speed can be adjusted according to needs. After the resistance is reduced, the rotation speed required to maintain the same air volume decreases, and the energy consumption decreases accordingly. In this case, the energy-saving effect of the low-resistance filter element is more easily reflected.

Group control system : When multiple units are linked, changes in overall resistance will affect the operating status of all units. The energy-saving effect must be calculated based on the entire system, not just a single unit.

Therefore, before comparing energy consumption, first confirm the control method of the system. For device-side applications such as The control method of the EFU equipment-side fan filter unit is often determined by the equipment host, and the room for adjustment is limited. The calculation must be based on the actual operating mode.

Operating time and dust accumulation also need to be taken into account

Energy consumption is the result of long-term accumulation and cannot just look at the initial state.

The data that need to be counted include: the number of hours in each operating mode throughout the year, the power of the fan in each mode, and the change process of the filter element from initial resistance to final resistance.

When the filter element accumulates dust, the resistance increases, and the energy consumption of the fan will change accordingly. The advantages of low-resistance filter elements may not be obvious in the early stages of operation, but as dust accumulates, the magnitude and speed of resistance increase may be different from ordinary filter elements. This part of the difference must be evaluated based on actual operating data and cannot rely on assumptions.

If the system has differential pressure monitoring, the resistance change trend over a period of time can be recorded and used to calculate the energy consumption difference throughout the cycle.

Maintenance costs are also included

The purchase price is only a portion of the total cost.

If the effective filtration area of ​​the low-resistance filter element is larger, the dust holding capacity may be higher, the replacement cycle may be longer, and the maintenance cost will be reduced accordingly. But if the structure is more complex and the unit price is higher, the initial investment will also increase.

The cost of downtime and replacement should also be considered. For continuous production, the downtime loss caused by replacing the filter element may be greater than the price difference of the filter element itself. This part should be estimated based on the actual situation of the project.

Comparing the purchase price, operating electricity costs, replacement frequency, and downtime costs together will give you the complete long-term cost. involving When selecting HEPA/ULPA air filters , it is recommended to list these items in the same table for comparison.

A practical comparison idea

Assume that a certain position originally used ordinary H14, and now evaluates the low-resistance H14 solution:

First measure the current air volume, fan gear and power, and record the pressure difference. Get the resistance curve of the low-resistance solution and calculate the new operating point and expected power based on the same air volume. Combined with the number of operating hours throughout the year, the difference in electricity bills is estimated. Then compare the unit prices, estimated replacement intervals and downtime costs of the two filter elements.

The result calculated in this way is more reliable than the calculation 'the resistance is reduced by 20%, so the energy is saved by 20%'. The specific energy saving range is subject to actual project measurements or calculations.

About Aili Industrial’s energy consumption accounting cooperation

Aili Industry can provide different configurations according to the project air volume, resistance and installation requirements. HEPA/ULPA air filter and complete machine supporting information. filter with FFU fan filter unit、The EFU equipment-end fan filter unit is matched in the same manufacturing system, and the filter element resistance and fan operating point can be calculated together at the planning stage.

For energy consumption comparison projects, it is recommended to provide target air volume, operating hours, control methods and current operating data to facilitate evaluation of program differences based on actual working conditions. Specific energy consumption data shall be subject to project calculations or actual measurement results.