Energy-saving test and evaluation method for air cooling fan cold end of thermal power unit

Abstract

The method for testing and evaluating the energy-saving of the air cooling fan cold end of a thermal power unit, comprising: numbering the air cooling fans at different positions, selecting the air cooling fans at the same positions before and after the modification, and arranging the field test measuring points; taking the air volume as the reference to judge the output of the fan; the output of the air cooling fan is related to the blade angle, the actual output of the fan is different at the same blade opening degree due to the different types of the fan before and after the modification, the blade angle of the fan is adjusted according to the results after the preliminary test until the output of the fan is the same; the selected fan is tested and compared, and the energy-saving effect is calculated. The present application can more accurately evaluate the energy-saving effect of the air cooling fan modification by determining whether the fan before and after the modification is in the same working condition through the two parameters of the rotating speed and the air volume of the fan.

Description

Technical Field

[0001] This invention relates to a method for evaluating the energy efficiency of air-cooled fans in air-cooled systems of large power plants. Background Technology

[0002] For air-cooled systems, the energy consumption of air-cooled fans is directly related to both the operating air volume and the fan efficiency. Currently, the main energy-saving technology for air-cooled fans focuses on optimizing the fan blades to improve fan efficiency and reduce energy consumption while maintaining the operating air volume. Accurately calculating and comparing the actual performance of air-cooled fans before and after modification is crucial for evaluating the success of energy-saving modifications. In some power plants, after air-cooled fan modifications, the operating air volume of the fans may decrease, and although the energy consumption may also decrease, this is a false impression of energy saving caused by sacrificing the fan's cooling capacity. This kind of "false energy saving" indicates an unsuccessful energy-saving modification. Furthermore, due to the "air-cooled island effect," even if the fans have the same design performance, their actual operating performance can vary significantly depending on their location and time. Therefore, there is an urgent need to develop an accurate energy-saving assessment method for air-cooled fans to evaluate the energy-saving effects before and after modifications. Summary of the Invention

[0003] In response to the impact of the "air-cooled island cluster effect" of air-cooled fans, this invention provides a method for testing and evaluating the energy-saving performance of the cold end of air-cooled fans in thermal power units, comparing power consumption under the condition that the output of air-cooled fans is the same.

[0004] The present invention is achieved using the following technical solution:

[0005] The energy-saving test and evaluation method for the cold end of the air-cooled fan of thermal power unit includes:

[0006] After numbering the air-cooled fans in different locations, select air-cooled fans with the same location before and after modification, and set up on-site test points; use air volume as the benchmark to judge the output of the fans; the output of the air-cooled fans is related to the blade angle. Since the fan types before and after modification are different, the actual output of the fans is different under the same blade opening. After preliminary testing, adjust the fan blade angle according to the results until the fan output is the same; conduct comparative tests on the selected fans and calculate the energy-saving effect.

[0007] A further improvement of this invention is that the environmental parameters that need to be measured before the test include ambient temperature, ambient wind direction, atmospheric pressure and ambient wind speed.

[0008] A further improvement of this invention is that during the testing period, rain, snow and extreme weather are avoided, and the ambient wind speed is less than 4 m / s.

[0009] A further improvement of this invention is that, after selecting the test fan location and test time, a measuring device is installed; environmental parameters are recorded once before, during and after the test; if the environmental parameters change by more than 5%, the test is terminated and retested at an opportune time.

[0010] A further improvement of this invention is that the test duration is controlled within 1 hour to avoid errors caused by changes in environmental parameters.

[0011] A further improvement of this invention lies in selecting 100% speed, 75% speed, 50% speed, and 30% speed conditions of the air-cooled fan for testing, and recording the fan airflow Q1~4 m³ / s respectively. 3 / h; wind pressure P1~4, Pa; and power W1~4, kW.

[0012] A further improvement of this invention is that, under the premise of ensuring stable environmental parameters, the air volume of the air-cooled fan before and after modification is tested under four operating conditions: 100% speed, 75% speed, 50% speed and 30% speed. Under each speed condition, the actual air volume of the modified air-cooled fan is controlled to be the same as that before modification by adjusting the blade angle of the air-cooled fan, and these are judged as the same operating condition.

[0013] A further improvement of this invention is that the fan's air volume, air pressure, and power parameters are recorded separately under the same operating conditions, and the improved fan's operating performance and energy-saving effect are accurately obtained by comparison.

[0014] The present invention has at least the following beneficial technical effects:

[0015] (1) More accurate assessment of the energy-saving effect of air-cooled fan retrofit: Determine whether the fan before and after the retrofit is operating under the same conditions by using two parameters: fan speed and fan air volume. This replaces the traditional method of using fan speed and fan opening degree as the benchmark. Because the fan type changes after the retrofit, the actual output of the fan at the same speed and opening degree will be different.

[0016] (2) Conduct on-site tests more quickly and accurately, and improve the accuracy of on-site measurements: The original flow meter was optimized into a wireless Bluetooth meter, and the test time for each working condition was shortened from the original 4-5 hours to about 1 hour, reducing the test time and avoiding test errors caused by large changes in environmental parameters. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the location distribution of air-cooled fans in an air-cooled island. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, the energy-saving test and evaluation method for the cold end of an air-cooled fan in a thermal power unit provided by this invention includes: numbering air-cooled fans at different locations, selecting air-cooled fans with the same location before and after modification, and setting up on-site test points; judging the output of the fan based on air volume; the output of the air-cooled fan is related to the blade angle. Since the fan types before and after modification are different, the actual output of the fan is different under the same blade opening. After preliminary testing, the fan blade angle is adjusted according to the results until the fan output is the same; comparative testing is performed on the selected fans, and the energy-saving effect is calculated.

[0020] The specific implementation method is as follows:

[0021] 1. Select the location of the air-cooled fan. Figure 1 This diagram shows a typical layout of air-cooled fans in an air-cooled island, with 7 rows and 11 columns of fans. Fans at typical boundary positions 1-1 and 1-7, and the middle position 4-4, were selected for testing.

[0022] 2. Determine the test environment parameters. These include ambient temperature, wind direction, atmospheric pressure, and wind speed. During the test, avoid rain, snow, and extreme weather conditions; the ambient wind speed should be less than 4 m / s.

[0023] 3. Test the air-cooled fan before modification. After selecting the test fan location and test time, install the measuring device; record environmental parameters once before, during, and after the test. If environmental parameters change significantly, the test should be terminated and retested at an opportune time; the test duration should be controlled within 1 hour to avoid large errors caused by changes in environmental parameters; test the air-cooled fan at 100% speed, 75% speed, 50% speed, and 30% speed, and record the fan airflow Q for each condition. 1～4 (m 3 / h), wind pressure P 1～4 (Pa) and power W 1～4 (kW).

[0024] 4. Test the modified air-cooled fan. After modification, select an air-cooled fan in the same location as the test object. Ensure that the ambient temperature, wind direction, atmospheric pressure, and wind speed are basically the same, with a deviation within 5%. Test the fan airflow Q of the modified air-cooled fan at 100%, 75%, 50%, and 30% speed conditions. 2～4 (m 3 / h), wind pressure P 2～4 (Pa) and power W 2～4 (kW).

[0025] 5. Evaluate the energy savings of the fans. Compare the power of the fans before and after the modification under the same operating conditions. There are two criteria for judging the same operating conditions: first, the deviation of the boiler evaporation rate should not exceed 2%; second, the deviation of the measured air volume of the air-cooled fan should not exceed 3%. If the air volume of the modified fan is different from that of the original fan under the same boiler evaporation rate and the same speed, the blade angle of the modified fan should be adjusted until the air volume deviation between the original and modified fans at the corresponding speed does not exceed 3%, i.e., |Q1-Q2| / Q1*100%≤3%. Statistically record the operating time H of the unit at 100% speed, 75% speed, 50% speed, and 30% speed. 1～4 (h), calculate the revised annual energy saving P = (W) 11 -W 21 )×H1+(W 12 -W 22 )×H2+(W 13 -W 23 )×H3+(W 14 -W 24 )×H4(kW·h).

[0026] Example

[0027] A domestically produced 2×600MW subcritical coal-fired direct air-cooled turbine unit has its three main components—boiler, turbine, and generator—designed and manufactured by Beijing Bawei Co., Ltd., Harbin Turbine Works Co., Ltd., and Harbin Electric Machinery Co., Ltd., respectively. The air-cooled island consists of 56 air-cooled fans. To implement energy-saving and consumption-reducing retrofits, the air-cooled fans were replaced with new 6-blade fans to improve the unit's operating economy and reduce the impact of fan resonance on the safety of the air-cooled island.

[0028] The energy-saving assessment method for air-cooled fans proposed in this patent was used to conduct comparative tests on the air-cooled fans before and after the modification. The main environmental parameters during the test are shown in Table 1 below. The deviations of the environmental parameters were all within 5%, which met the test requirements.

[0029] Table 1 Test Environment Parameters

[0030] project unit Before the modification After revision Ambient temperature ℃ 23 22 Ambient wind speed m / s 3 3 Environmental wind direction / northwest northwest Atmospheric pressure Pa 101200 101035

[0031] Calculations and comparisons of air-cooled fan power consumption data show that the energy-saving effect of the fresh air units under high-speed operation (70%–110% speed) is significant. Specifically, at 70% speed, the power of a single fan decreases by 4.4kW, and the average power decrease for 56 fans is 246.4kW, resulting in an annual power saving of approximately 1.23 million kWh (based on 5000 hours of operation per year). At 100% speed, the power of a single fan decreases by 15.2kW, and the average power decrease for 56 fans is 851.2 kWh, resulting in an annual power saving of 4.25 million kWh (based on 5000 hours of operation per year). This represents a 14.5 percentage point reduction in power consumption, corresponding to a 0.142 percentage point reduction in plant power consumption rate, demonstrating a significant energy-saving effect. The test results were unanimously recognized by the owner and the equipment manufacturer.

[0032] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for testing and evaluating the energy efficiency of the cold end of an air-cooled fan in a thermal power unit, characterized in that, include: After numbering the air-cooled fans in different locations, select the air-cooled fans with the same location before and after the modification, and set up on-site test points; The output of the fan is judged based on the air volume. The output of the air-cooled fan is related to the blade angle. Since the fan types before and after the modification are different, the actual output of the fan is different under the same blade opening. After preliminary testing, the fan blade angle is adjusted according to the results until the fan output is the same. Comparative tests are conducted on the selected fans to calculate the energy-saving effect. The environmental parameters that need to be measured before testing include ambient temperature, ambient wind direction, atmospheric pressure, and ambient wind speed. After selecting the test fan location and test time, install the measuring device; record environmental parameters once before, during and after the test. If the environmental parameters change by more than 5%, terminate the test and retest at an opportune time. Tests were conducted on the air-cooled fan at 100% speed, 75% speed, 50% speed, and 30% speed, and the fan airflow Q1–4 m³ / s was recorded respectively. 3 / h; wind pressure P1~4, Pa; and power W1~4, kW.

2. The energy-saving test and evaluation method for the cold end of an air-cooled fan in a thermal power unit according to claim 1, characterized in that, During the test, rain, snow and extreme weather should be avoided, and the ambient wind speed should be less than 4 m / s.

3. The energy-saving test and evaluation method for the cold end of an air-cooled fan in a thermal power unit according to claim 1, characterized in that, The test duration should be kept within 1 hour to avoid errors caused by changes in environmental parameters.

4. The energy-saving test and evaluation method for the cold end of an air-cooled fan in a thermal power unit according to claim 1, characterized in that, Under the premise of ensuring stable environmental parameters, the air volume of the air-cooled fan before and after modification was tested under four operating conditions: 100% speed, 75% speed, 50% speed and 30% speed. Under each speed condition, the actual air volume of the modified air-cooled fan was controlled to be the same as that before modification by adjusting the blade angle of the air-cooled fan, and it was judged as the same operating condition.

5. The energy-saving test and evaluation method for the cold end of an air-cooled fan in a thermal power unit according to claim 4, characterized in that, Record the fan's air volume, air pressure, and power parameters under the same operating conditions, and accurately obtain the modified fan's operating performance and energy-saving effect by comparison.

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