Noise Reduction Techniques in HVAC Compressors

Co-rotating scroll compressor for improved quietness. The scroll compressor has a driving scroll and a driven scroll that rotate around eccentric axes. To improve quietness, the scrolls have reduced thickness portions near the opposing scroll ends. These protrusions align the center of gravity of each scroll's spiral portion closer to its axis. This reduces dynamic imbalance during rotation compared to having thick scroll ends.

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Window-type air conditioner design to reduce noise transfer between the indoor and outdoor units. The air conditioner separates the compressor and outdoor heat exchanger from the indoor unit. It connects the two modules with a support that has soundproofing around the refrigerant pipe. This prevents noise from the compressor reaching the indoor space. The support also has features to improve connection strength considering the external forces applied to the window-mounted air conditioner.

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Reciprocating compressor design with reduced vibration transmission to the enclosure and improved discharge gas flow at high speeds. The compressor has multiple flexible discharge hoses connecting the discharge muffler and discharge pipe. This allows vibrations from the compressor body to be isolated from the enclosure since the flexible hoses can move independently. It also prevents clogging of the discharge gas during high-speed operation since the flexible hoses can accommodate any expansion/contraction of the discharge gas.

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Reducing noise in devices like compressors and ducted air movers by using a noise-damping resonator. It involves adding an acoustic resistive screen over an aperture between the air flow duct and a gas-filled cavity. The screen resists airflow between the duct and cavity, forming a resonator that attenuates noise in a target frequency band. The screen characteristics are optimized based on duct, cavity, and aperture geometry to maximize noise reduction.

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Heat pumps represent an essential component of the energy transition. While they are effective in generating heat, also generate sound, which has potential to cause annoyance. Therefore, it is enhance transparency sound behavior. Analyses were performed identify factors influencing levels at both and system levels. A total three refrigerant compressors examined with objective determining most acoustically efficient components currently available key acoustics. Two low-noise axial fans used illustrate differing characteristics when a heat pump application. Based on tests measurements level, speeds compressor fan confirmed as significant emissions air-to-water pumps. In addition, flow temperature operating point identified influencing. The results employed develop improved demonstrator. model could be developed that capable describing behavior for wide range conditions. This methodology allows increased Different behaviors can demonstrated basis model, discussions definition maximum specifications held data. Sound should not only linked output, this increases uncertainty comparability.... Read More

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Air-cooled compressor installation with improved fan housing for radial fans to reduce pressure drop, noise, and improve airflow. The fan housing has the fan inlet and outlet parallel planes. The fan axis at an angle between 0-45° to the inlet plane. The outlet edge doesn't intersect the fan axis extension to avoid bending airflow. This eliminates the need for the fan to bend airflow through a 90° turn at the outlet, reducing pressure drop and noise.

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A rotary compressor design for reducing noise, vibration and improving efficiency in air conditioners, refrigerators, and heaters using natural refrigerants like CO2. The compressor has a discharge space with 3-10 times the cylinder volume to mitigate pulsation when the gas exits the compression chamber. This reduces pressure fluctuations and noise compared to conventional compressors. The discharge space is formed by recessing one end plate and covering it with a separate plate.

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A piston rod mechanism for an air compressor that reduces noise during operation. The mechanism has an intake valve secured to the piston with pivot pins. It also has a receiving portion in the piston to house the closed intake valve. This allows the intake valve to oscillate relative to the piston as it moves. The receiving portion prevents the valve from contacting the piston and generating noise when the valve is closed. This improves the overall noise level of the air compressor. The valve can be made of silicone, the rod of plastic, the bearing of metal, and the piston ring of rubber to further reduce noise.

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Apparatus for damping pressure pulsation in a refrigerant compressor that reduces noise without significant pressure loss. It has a piston in a housing that can move to control flow area. The piston has seals to create chambers that expand the fluid as it flows. This dampens pressure pulsations when the compressor has low flow. The piston moves between closed and fully open positions. The chambers allow flow when the piston is not at the ends. The piston seals contact the housing seals. This simple, compact design with minimal components and materials reduces costs and space requirements compared to complex valves or silencers.

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A linear compressor for compressing a refrigerant using a piston that linearly reciprocates in a cylinder. The compressor has two muffler units to improve noise filtering, intake efficiency, and space efficiency. The first muffler is between the piston and back cover. The second muffler surrounds the first muffler and has a communication hole between the inner and outer mufflers. This allows fluid flow between the mufflers. The outer muffler also surrounds the cylinder opening. This dual muffler setup filters noise, improves intake efficiency by capturing and compressing more fluid, and saves space compared to a single muffler.

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Abstract In this paper, a systematic experimental study is carried out on the overclocking operation of chillers. Based platform under nominal refrigeration conditions, evolution key performance parameters such as evaporation pressure, condensation capacity, power, and noise different driving frequencies was tested. The results show that with increase frequency, capacity increases linearly, while coefficient chiller decreases significantly, sound pressure level shows nonlinear acceleration upward trend. This achievement can provide theoretical basis engineering decision support for selection design chillers, frequency conversion optimization, energy efficiency-noise collaborative control in industrial field.

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Motor-driven compressor with improved heat dissipation and noise reduction. The compressor has an inverter to convert DC power to AC for the motor. A noise reducing unit at the inverter input reduces common mode and normal mode noise in the DC power. The inverter case is thermally coupled to the compressor housing. A damping unit forms a magnetic path for the choke coil leakage flux and increases choke inductance. This damping unit covers part of the choke coil side surface and is thermally coupled to the inverter case and compressor housing for heat dissipation.

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Heat pump water heater with mufflers to reduce noise transmission from the compressor. The heat pump water heater has mufflers, an inlet muffler between the compressor and air inlet, and an outlet muffler between the compressor and air outlet. These mufflers prevent sound waves generated by the compressor from traveling through the air inlet and outlet and escaping the water heater, reducing exterior noise levels.

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Electric compressor for refrigeration applications that has reduced noise, vibration, and pulsation compared to prior art scroll-type electric compressors. The compressor has features like a modified fixed scroll floor, an isolation/constraint system, and a reed mechanism in the head. These reduce oscillations and pulsations during operation that can transmit to the housing and cause noise, vibration, and durability issues. The modified scroll floor reduces articulation and oscillations of the scroll. The isolation/constraint system isolates the housing from compressor oscillations. The reed mechanism in the head releases compressed refrigerant earlier from side ports before the central port to prevent strong pulsations in the refrigerant flow.

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Electric compressor for refrigeration systems that compresses refrigerant using a scroll compression device. The compressor has features to improve efficiency, reduce noise, and extend durability compared to prior scroll compressors. These include: 1. Swing-link mechanism with integrated limit pin to replace separate drive and eccentric pins. This simplifies and strengthens the connection between the drive shaft and swing-link. 2. Discharge head with an integrated oil separator to separate oil from refrigerant before exiting. 3. Scroll bearing with oil injection orifice to ensure adequate oil lubrication. 4. Bearing oil communication hole in the drive shaft to improve oil flow to bearings. 5. Dome-shaped inverter cover to reduce vibrations and noise.

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Motor-driven compressor with a noise reduction circuit to mitigate EMC issues. The noise reduction circuit is integrated into the inverter device which converts DC power to AC power. It uses a common mode choke coil with a divided annular conductor. One section of the conductor is thermally connected to the housing and the other section is thermally connected to the main body. This allows induced current to flow around the coil in a circumferential direction, reducing leakage flux. The divided conductor section with lower resistance and thermal conductivity helps dissipate heat generated by the induced current to the housing.

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Motor-driven compressor for vehicle air conditioners with improved noise reduction. The compressor has a housing containing the compression unit, motor, and inverter. The inverter has a noise reducing unit with a common mode choke coil, smoothing capacitor, and two damping portions. One damping portion is nonmagnetic and surrounds the coil windings to reduce normal mode noise by generating magnetic flux to resist leakage flux. The other damping portion is magnetic and reduces normal mode noise on the opposite side of the coil. This configuration helps damp common mode and normal mode noise in the compressor inverter.

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A noise reduction refrigeration system for household appliances that achieves a lower noise level than conventional low-temperature systems. The system employs a unique configuration where the high-pressure side of the low-temperature refrigeration cycle loop operates within a narrower pressure range compared to conventional systems. This configuration enables the low-pressure side of the refrigeration cycle loop to operate within a broader pressure range, allowing the low-pressure compressor to achieve a lower suction pressure and exhaust pressure. The system achieves this by configuring the high-pressure side to operate at a lower absolute pressure range (2-11 bar) and the low-pressure side to operate at a higher absolute pressure range (0.2-1.1 bar), thereby reducing the overall system pressure drop and resulting noise.

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A heat pump compressor noise reduction device for household air source heat pumps that effectively reduces compressor noise while maintaining system performance. The device comprises a compressor body, a vibration-damping pad fixed to the bottom of the compressor body, a top cover that covers the compressor body, and a surrounding plate that encloses the compressor body between the top cover and the bottom plate. This design provides optimal damping of the compressor's vibration through the vibration-damping pad, while the top cover and surrounding plate work together to provide effective noise reduction around the compressor.

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A compressor design to reduce compressor noise in air conditioning systems. The design incorporates a unique muffler configuration that optimizes airflow management through the exhaust port. By strategically positioning the muffler's mounting structure, the system achieves a specific axial depth ratio (H) that balances airflow velocity and pressure drop. This configuration enables the compressor to operate within a narrower range of axial depths, thereby reducing the noise generated by the exhaust port. The design ensures structural integrity while maintaining optimal airflow characteristics, resulting in a quieter compressor operation.

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