A clunking noise issue is recently found in an air conditioning outdoor unit, and the main cause of the noise is experimentally identified to be the impact of the scrolls in the compressor unit during the switching process. Specifically, the time to close the discharge valve after the main valve is closed is not very important. The compressor studied is a digital scroll compressor. With continuous modulation comes precise temperature control, and that's what a digital scroll compressor provides. You can be signed in via any or all of the methods shown below at the same time. By applying the new semi-active control method, both the original main valve and the additional valves are controlled by the new control system. The unit provides greater energy efficiency and lower running costs by precisely matching refrigeration load. During the t ime the members are separated, there is no gas compression and approximately 10% power usage. Compact, quiet, easy to use and cost-efficient. There also exist some differences in the middle frequency (700 Hz) and high frequency (1200–1600 Hz) ranges. Simply select your manager software from the list below and click on download. Due to the high pressure difference between the low-pressure suction chamber and the high-pressure modulation chamber, the pressure differential force overcomes the spring force and then the up-scroll is pushed downwards and coincides with the low-scroll. The discharge valve with an opposite effect to the release valve is found useful for solving the noise issue. A needle valve with a smaller diameter pipe is also attached to adjust the flow through the effective area size. Simply select your manager software from the list below and click on download. (even though the Carrier sales brochure said its Scroll compressor virtually make no noise.) Although the pressure conditions can be complex in the chambers during working condition, the pressure at boundary conditions of the compressor would be fixed due to its component mechanism. Figure 8 shows the pressure changes when using different controlling methods. View or download all the content the society has access to. Both noise and vibration results confirm that the impact noise in the frequency range of interest can be reduced by using the proposed semi-active control methods. With over 26 million scrolls installed, and thousands in refrigeration applications, Copeland understands your need for reliability. ... and the fact that it has no valves to create valve noise, the scroll compressor produces very low gas-pulsation noises and very little vibration when compared to piston-type compressors. During the loaded state the compressor operates like a standard Scroll and delivers full capacity and mass flow. Brinmar's universal design accommodates hundreds of different styles and shapes of compressors. The low-pressure chamber is directly connected to the atmosphere, where it can be considered as at a steady pressure level. The application envelopes for Digital refrigeration Scroll compressors are … If you have access to a journal via a society or association membership, please browse to your society journal, select an article to view, and follow the instructions in this box. KRST– Tank-mount belt drive compressor ranging from 5 HP to 30 HP. The main challenges for addressing this clunking noise issue are in three aspects. A manual digital control system, independently from the original operating system, is programmed by using the LabVIEW.13 The new control system can directly control the open/close state up to three different valves. Figure 1. Figure 5. Figure 13. The email address and/or password entered does not match our records, please check and try again. Lean Library can solve it. The discharge valve with an opposite effect to the release valve is found useful for solving the noise issue. New or replacement RoofPak units with inverter compressors drastically increase energy efficiencies and lower operating costs when compared to rooftop units using standard efficiency fixed or digital scroll compressors. According to the feedback from the probes, the main control system decides the open/close state of the main valve. Northern china heat pump application with the digital heating scroll compressor. The pressures at changing loaded/unloaded status are found to be 2.7–3.0 bar, which means the up-scroll moves up or down at 2.7–3.0 bar pressure difference between the inside and the outside of the modulation chamber (each outlet: discharge or suction outlet). It can be clearly seen that there is about 10 dB difference around 160 Hz. Since the noise is mainly produced due to the vertical motion of the scrolls and their impacts, two accelerometers are located on the compressor top and foot to measure the accelerations in the vertical direction. Figure 4. The noise performances are shown in Figure 11. There also exist some differences in the middle frequency (700 Hz) and high frequency (1200–1600 Hz) ranges. The impact noise became unnoticeable. United States patent US 9,638,191 B2. Zpd72kce-tfd-433 Copeland Digital Scroll Compressor For Air Conditioner , Find Complete Details about Zpd72kce-tfd-433 Copeland Digital Scroll Compressor For Air Conditioner,Scroll Compressor,Digital Scroll Compressor,Copeland Digital Scroll Compressor from Refrigeration & Heat Exchange Parts Supplier or Manufacturer-Dongguan Mei Tuo Electrical And Refrigeration Equipment Co., Limited A total of three tests are conducted to study the effects of the additional valves. In the case of a digital scroll the same issues would occur and fitting the NRV should have solved the problem, but when the compressor is running in an unloaded state if the NRV fails to close then the gas will try to equalise even though the compressor is running and would make the scroll set vibrate and be very noisy. of his kindness. 2), the addition of an internal unloading mechanism in the scroll compressor opens a bypass port or vent at the end of the first compression pocket. Thus, the contact speed of the scrolls and the noise issue can be controlled. A discharge valve connects the modulation chamber to the high-pressure discharge outlet, as shown in Figure 7. Digital scroll compressors are highly flexible to match those changing loads, from 10% to 100% BTUH capacities with just one compressor. Members of _ can log in with their society credentials below, Journal of Low Frequency Noise, Vibration and Active Control, https://creativecommons.org/licenses/by/4.0/Creative Commons CC-BY: This article is distributed under the terms of the Creative Commons Attribution 4.0 License (. Login failed. Figure 3 shows the noise spectrum comparison between the sound with knocking component and the sound without knocking component by using the fast fourier transform (FFT) algorithm. Noise level and noise spectrum comparison with and without the added discharge valve: (a) baseline (blue) and (b) discharge valve (red). If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. 22 April 2016 Categories: , Blog The compressor is one of the most important parts of an air conditioning system since it is the compressor that pushes out the initial refrigerant that fuels the entire cooling process. For more information view the SAGE Journals Article Sharing page. The reason could be the pressure difference inside the chamber and the suction outlet is not big enough to hold the two scrolls contacted tightly and continuously. For over 75 years, the name BITZER has stood for worldwide leading compressor technology which gives you complete confidence in any refrigeration or air conditioning application. For a typical evaporator-expansion valve configuration a minimum stable superheat of at least 5K is required. It makes bad noise and vibration whenever the compressor goes on unloaded state because of capacity control. Capacity modulated scroll compressor. Figure 1 shows the schematic of a simplified digital scroll compressor according to the corresponding model designs.4–6 A solenoid valve is used to control the two working states of the compressor, namely loaded and unloaded. I have read and accept the terms and conditions, View permissions information for this article. Refrigeration loads are often changing. Figure 13 shows the comparison of the sound pressure level with and without the added discharge valve opposite operation to the main valve. ‎Upper Saddle River: View or download all content the institution has subscribed to. Noise level and noise spectrum comparison with and without the added discharge valve: (a) baseline (blue) and (b) discharge valve (red). Feb 25, 2016 - Explore sunwoo chung's board "Scroll Compressor", followed by 515 people on Pinterest. The reason is that the pressure level in the modulation chamber would increase quickly to the pressure level in the high-pressure chamber under the operation of both the discharge valve and the main valve. The reason is that the pressure level in the modulation chamber would increase quickly to the pressure level in the high-pressure chamber under the operation of both the discharge valve and the main valve. However, as I walk around my neighborhood, there is a noticeable and annoying hum/buzz from all the scroll compressors regardless of brand. Pressure changes in in the modulation chamber: C0, baseline (black); C204, 0.2 s per-release (green); and C301, 0.2 s per-release with a 4 times/s multi-open/close (red). This type of compressor is most commonly seen where a small amount of oil-free air is needed. Although the pressure conditions can be complex in the chambers during working condition, the pressure at boundary conditions of the compressor would be fixed due to its component mechanism. A pressure sensor is placed at the modulation chamber to monitor its pressure change. A clunking noise issue is recently found in an air conditioning outdoor unit, and the main cause of the noise is experimentally identified to be the impact of the scrolls in the compressor unit during the switching process. Get clean and noise free compressed air with a scroll compressor, which is a quiet and reliable type of compressor. Prasad, BS, Moeller, P, Sheridan, J. Thermo-fluid mechanics of fluid injection and refrigeration system performance improvement. compressor suction inlet must always be sufficient to ensure that no refrigerant droplets enter the compressor. Since the noise is mainly produced due to the vertical motion of the scrolls and their impacts, two accelerometers are located on the compressor top and foot to measure the accelerations in the vertical direction. The baseline results are recorded before and after activating the additional valves and can be compared to check the repeatability of the experiments. It is found that the control methods are able to reduce the clunking noise of the digital scroll compressors to an acceptable level. It can be clearly seen that there is about 10 dB difference around 160 Hz. The semi-active control model and controlling methods will be designed based on the results of the system identification tests. Figure 7. The instability contact (the pressure differential force equal or almost equal to the spring force) of the two scrolls due to the small pressure difference between the chamber and the suction outlet could lead to the louder rattling sound. It can be clearly seen that the knocking component (as indicated area) is reduced significantly from 60 dB(A) to 46 dB(A). Then the effects of two types of additional valves are examined in an operating system. Inverter compressor is much better than digital scroll compressor, since it varies the speed of the motor in accordance with the load and thus saves energy when the load is less than maximum capacity. By applying the new semi-active control method, both the original main valve and the additional valves are controlled by the new control system. Compact, quiet, easy to use and cost-efficient. 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