How much will the added resistance of the chemical filter increase the fan's electricity consumption?

Straight answer: There is no single answer. The amount of increased electricity consumption depends on the actual air volume, fan efficiency, control method and operating time.

Some people may ask: If a chemical filtration section is added and the pressure difference is increased by dozens of pascals, how much will the electricity bill increase? This problem cannot be simply estimated by 'multiplying the pressure difference by the air volume'. The pressure difference is only one of the inputs. The actual power depends on the efficiency of the fan at this operating point and how the control system responds.

First distinguish whether the air volume is maintained

After adding a filter section, the system resistance increases. How the wind turbine reacts depends on how it is controlled.

Fixed speed fan. When the rotational speed remains unchanged and the system resistance increases, the operating point moves to the left along the fan curve. The air volume decreases and the static pressure increases. The input power may not change much, or even decrease slightly due to the reduction in air volume. In this case, the increase in power consumption is not obvious, but the air supply volume may be insufficient.

Variable frequency or EC blower. If the control system wants to maintain the original air volume, the rotation speed will automatically increase. As the rotational speed increases, the input power increases. The amount of rise depends on the fan curve and the position of the new operating point.

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

In both cases, the direction of change in electricity consumption may be opposite. Fixed-speed fans may save power but do not have enough air volume, while variable-frequency fans maintain air volume but consume more electricity. Before discussing 'how much to increase electricity consumption', let's first clarify the control method. Please refer to the specific air volume selection. Discussion on whether the chemical filter air volume should be selected based on the total air volume of the system or the air volume of a single unit .

Compare complete running costs

The new headwinds bring about more than just changes in electricity bills.

Initial investment. The chemical filtration section itself has a purchase cost. If the original fan has insufficient margin and needs to be replaced, there will also be a replacement cost for the fan or motor.

Running electricity bills. When the variable frequency fan maintains air volume, the rotation speed increases and the input power increases. The specific amount of increase needs to be calculated or measured based on the actual working point. For specific accounting methods, please refer to Discussion on how to check the original motor load when rebuilding a chemical filter .

Maintenance costs. The chemical filter section has a different replacement cycle than the particle filter. The cost of filter material replacement, downtime losses, and labor costs must be included in the long-term operating costs. For specific life assessment, please refer to Discussion of how long chemical filters last .

A low-resistance option may be more cost-effective. To also meet the gas treatment goals, choose a chemical filtration section with a larger effective area, lower resistance, and potentially lower long-term electricity bills. Please refer to the selection when the specific thickness is limited. Discussion of how to determine configuration when chemical filter thickness is limited .

Don’t just look at the purchase price. If cheap filter media has high resistance and needs to be replaced frequently, the total cost may be higher.

Calculate using actual data

The basis of energy consumption accounting is operating data.

Record data before and after the transformation. Under the same air volume or the same control gear, record the filter section pressure difference, fan current or input power, and air volume. The measurement methods of three-phase motors and single-phase motors are different, so measure according to the corresponding methods.

Compare the same operating point. If the air volume changes after the transformation, part of the power difference comes from the change in air volume and cannot be entirely attributed to the filter section resistance. The power should be compared under the same air volume, or converted according to the fan curve.

The running time should be accurate. The number of hours in each operating mode is different throughout the year, and the power in working mode and duty mode is also different. Statistics are performed separately and then weighted to calculate annual electricity consumption. For specific operation records, please refer to Discussion of what items should be checked during daily inspection of chemical filters .

Theoretical estimates should state assumptions. If the on-site measurement conditions are limited, the fan curve and power formula can be used to estimate, but the assumed fan efficiency, motor efficiency and operating conditions must be stated. Actual values ​​may differ from estimates.

Don’t commit to a uniform increase in power consumption. The fan efficiency, control method and operating time of different systems vary greatly. The same filter section is installed in different systems, and the power consumption changes may be different.

Taking into account gas treatment goals

Energy consumption is only one dimension of program evaluation.

The filter section has low resistance, but the gas treatment is not up to standard and is meaningless. When selecting a model, first confirm the medium's ability to handle the target gas, and then compare the resistance. For specific selection principles, please refer to Discussion on why chemical filters should be selected according to the target gas .

Air volume maintenance and gas effect must be verified at the same time. After the modification, measure the air volume and outlet concentration to confirm that both meet the requirements. For specific sampling methods, please refer to Discussion of sampling points for chemical filter performance verification .

System balance cannot be ignored. After adding a filter section, the air volume distribution may change. The branch air volume needs to be rechecked to avoid insufficient air volume in some areas. For specific methods, please refer to whether chemical filtration modification requires re-doing the air volume balance . Discuss

Project judgment example

A chemical filtration section was added to an old air conditioning system, with an initial resistance of about 70 Pa and a final resistance of about 140 Pa. The original fan operates at a fixed speed. After the modification, the air volume dropped by about 12% and the input power dropped slightly. Although the electricity bill has not increased, the air supply volume at the end is insufficient and the fan gear needs to be adjusted.

After the adjustment, the fan speed was increased by one gear, the air volume returned to the original design value, and the input power increased by about 8% compared with before the transformation. Calculated based on 6,000 hours of operation throughout the year, the annual electricity bill will increase by approximately XXX yuan (the specific amount is calculated based on local electricity prices and actual power). This increase is within the project budget.

Another project uses a chemical filtration section with a larger effective area, which reduces the resistance by about 30%. While maintaining the air volume, the input power only increases by about 4%.

These two cases illustrate that the increase in electricity consumption depends on the fan control method and the filter section resistance. involving When selecting a chemical filter product series , it is recommended to provide the fan parameters, operating data, target air volume and resistance requirements to the supplier for verification.

Key points for selection and acceptance inspection

About Aili Industrial’s energy consumption accounting package

Aili Industrial has independent manufacturing capabilities in filters, motors, fans, control systems and sheet metal processing, and can provide chemical filter product series and supporting air supply equipment. For renovation projects that need to calculate energy consumption, fan parameters, system resistance, target air volume and operating hours can be combined to assist in checking the chemical filtration section configuration and energy consumption plan.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Providing fan parameters, operating data and modification requirements when enquiring, will help confirm the appropriate solution. The specific selection is subject to the technical documents and test results confirmed by the project.