Refrigeration Compressor Research Articles

Strength Research Based on ABAQUS for the Fixed Plate of the Refrigerator Compressor

The compressor fixed plate in the refrigerator plays an important role in carrying the compressor and connecting various parts, which is very important to the structure of the refrigerator. In this paper, the finite element (FE) software ABAQUS is used to check the strength of the compressor base plate of thicknesses of 1.2 mm and 1.5 mm. Firstly, the model establishment and mesh treatment method of the fixed plate of the refrigerator compressor is introduced, then the load and constraints are described. Finally, the FE analysis is carried out, and the plates of 1.2 mm and 1.5 mm thicknesses are contrasted, respectively. And the stress-strain diagrams are obtained, which provide a theoretical basis for the design and optimization of the compressor fixed plate.

Research on the Technologies of the Compressor Remanufacturing Process

This study describes the remanufacturing process scheme and key technologies of waste compressors. Firstly, the technical characteristics of compressors for home appliances such as refrigerators and air conditioners are summarised. Then, the remanufacturing process scheme is proposed with the waste refrigerator compressor as the research object. The purpose or requirements of key processes such as separation, disassembling, cleaning, detecting, remanufacturing and reassembling are also elaborated. Moreover, the corresponding remanufacturing technology or method is proposed to satisfy the structural, quality requirement, economy and environmental friendliness of products and components. The cleaning technology of the compressor motor stator and the remanufacturing technology of crankshaft is highlighted. In accordance with the structural and quality requirement of the motor stator, the cleaning method of the motor stator is proposed, and the environmental friendliness, economy and safety of several cleaning agents are analysed. The scheme of crankshaft remanufacturing is proposed on the basis of the failure form of the crankshaft and the quality requirement of remanufacturing. Moreover, the process parameters are described.

The Assessment of Environmental Impact of the Chicken Meat Agroindustry in Indonesia: Life Cycle Assessment (LCA) Perspective

Chicken meat agroindustry is one of the industries that contribute to environmental impacts. The environmental impacts are due to the use of resources, energy, and waste along the chicken meat chain. This study aimed to evaluate the environmental impacts along the life cycle of the chicken meat chain from cradle-to-grave using a life cycle assessment (LCA) approach. The data inventory consisted of inputs and outputs from five sub-systems: feed production, broiler production on the farm, carcass production at the slaughterhouse, supplier distribution, and consumer use. The impact categories included global warming, acidification, and eutrophication. The process of impact calculation used the CML-IA (Centre of Environmental Science of Leiden University Impact Assessment) baseline method on the SimaPro software. The results showed that consuming 1 kg of fried chicken resulted in a global warming impact of 5.86 kg CO 2 eq, acidification of 38.3 g SO 2 eq, and eutrophication of 24.1 g PO 4 3- eq. Feed production, litter, and energy usage were the most significant contributors to the environmental impacts. Improvement scenarios in reducing environmental impacts included reducing crude protein in feed, composting litter, installing inverters on refrigeration compressors, and electrical energy efficiency. The present study indicated the importance of environmental impact assessment on the entire chicken meat chain to improve environmental performance in the Indonesian chicken agroindustry.

Research on the influence of check valve on noise performance of variable frequency scroll refrigeration compressor

Check valve is one of the core components of the scroll refrigeration compressor, which can directly affect its efficiency, life, and noise performance. Traditional check valve is the reed valve. This paper deeply studies the dynamic characteristics of reed valve and reveals the main reason of the valve noise under different rotation speeds. The large noise is mainly attributing to the large pressure pulsation as well as fast circulation velocity of fluid and the severe slapping of the reed plate on the valve seat, which is influenced by the high pressure ratio of the working condition and stiffness of the reed valve. In order to reduce the noise of the check valve, the circular valve is designed to replace reed valve in this paper. At each rotation speed, the circular valve shows a continuous exhaust process, which avoids the slapping of the valve plate on the valve seat. More importantly, the exhaust is smooth and the pressure pulsation as well as the flow rate of the fluid is reduced significantly leading to the low aerodynamic noise. Therefore, compared with the reed valve compressor, the sound pressure level of the circular valve compressor at 1800, 4200, and 6600 rpm is decreased by 3.0, 5.2, and 0.3 dB, respectively.

Process design of advanced LNG subcooling system combined with a mixed refrigerant cycle

LNG subcooling system is a conventional system to keep the pressure of an LNG storage tank for LNG carriers, but has a weak point of the low efficiency resulting in a new BOG reliquefaction system. This study suggests a new LNG subcooling system combined with mixed refrigerant cycle (MR-SLNG), which can increase efficiency significantly. The results show the coefficient of performance (COP) of the system becomes 2.5 times higher than that of the conventional LNG subcooling system based on a reverse Brayton cycle (RBC-SLNG). Additionally, MR-SLNG can be a compact system because the volumetric flowrate of the refrigerant compressor decreased to 8.9%, which brings additional benefits to the ship design.

A new optimization method of energy consumption for dynamic boil-off gas

Related research on refrigerant optimization based on the dynamic BOG has yet to be proposed. This study offers a new dynamic optimization method for boil-off gas (BOG) re-liquefaction system to improve the system's energy efficiency. The performance of C3MR (the propane precooling mixed refrigerant cycle) is analyzed based on the steady state model of leading liquefaction equipment in the process simulation in Aspen HYSYS software. And the principle of the energy consumption variation law of propane precooled compressor and mixed refrigerant compressor, based on the actual possible disturbance range obtained in the natural gas liquefaction process, is applied to construct the multi-objective optimization model with minimum energy consumption and maximum heat exchanger efficiency. Finally, the dynamic responses of disturbances were achieved and discussed with the aid of GA (Genetic Algorithm) and PSO (particle swarm optimization). The optimized performance of the dynamic liquefaction cycle is 34.8% better than the steady condition system in terms of energy efficiency, and the maximum energy consumption can be reduced by 50.60%. The advantage of the proposed optimization framework is its adaptability to other dynamic liquefaction processes. It has practical reference significance for the cost control of the BOG re-liquefaction recovery project.

Effect of flow channel structures and refrigerants on the motor cooling process of compressor with gas bearings

Energy-saving and environment-friendly water chiller is the development trend. The efficient compressors and new refrigerants are hot spots. The gas bearing can significantly improve the performance of centrifugal refrigeration compressors, and effective motor cooling is the guarantee of performance and reliability. The influence of channel structure and refrigerant on the performance of the motor cooling process and refrigeration system is analyzed. The results show that adding the bearing gas supply circuit decreases the motor temperature and the maximum variation of permanent magnet temperature is about 60 °C. The cooling channel structure in the interlayer of the motor shell will affect the cooling process. The spiral channel can reduce the stator temperature and improve the uniformity of temperature distribution. But the temperature of the motor changes slightly when the length of the channel is more than 6000 mm. The motor temperature is the highest with refrigerant R1234ze(E), followed by it R1234yf and R134a. The maximum temperature of the permanent magnet for R1234ze(E) is 20–50 °C higher than it for R1234yf and 50–60 °C higher than it for R134a under different inlet diameters. The maximum temperature of the permanent magnet for R1234ze(E) is 30 °C higher than it for R1234yf and 50 °C higher than it for R134a under different inlet temperatures. The system with a motor cooling circuit has controlled the motor temperature within the safe operation range, while the COP of systems with R134a, R1234yf, and R1234ze(E) has only decreased by 4.63 - 5.36%, 4.22 - 4.6%, and 3.78 - 4.15% respectively.

Digital design and experimental testing of a compressor's suction muffler transmission loss

Abstract The purpose of this paper is to provide a fast, efficient, and low-cost digital design method for the design of suction mufflers in refrigerator compressor plants. The main content of this paper is to establish a three-dimensional acoustic model of the compressor suction muffler by using Solidedge software, combine the upper suction port of the muffler with the valve group, then use Hypermesh to mesh the acoustic model and carry out the theoretical calculation, transform the control differential equation in the solution domain into the integral equation on the boundary by Green's function, discretize the boundary and carry out the numerical solution. The boundary is discretized and solved numerically. The transfer matrix quadrupole parameters are used to describe the acoustic components, and the transfer matrix of the discontinuous cross section is obtained to transform the complex system into a chain superposition of simple systems. The dependent variable in the partial differential equation to be solved is changed to a linear system of equations, and the transmission loss is calculated from the incident and transmitted sound pressure. The theoretical calculation of the transmission loss of the muffler is performed using LMS. Virtual. Lab software and the design solution is continuously optimized using this software. The experimental analysis shows that the designed muffler is printed and trimmed by 3D printing equipment and loaded onto the transmission loss test bench for experimental testing, and the highest theoretical value differs from the test result by 10dB.

Study on non-uniform internal pressure distribution of twin-screw refrigeration compressor

To achieve higher efficiency of twin-screw compressors for refrigeration, the non-uniform internal pressure distribution in the rotor chamber and the flat section in the p-θ diagram were investigated in this paper. A three-dimensional CFD model of a twin-screw refrigeration compressor for chillers was established to analyze the generating mechanism of the flat section in the p-θ diagram. The p-θ diagrams of the compressor were compared under different rotational speeds and working fluids. Analysis results showed that the flat section in the p-θ diagram is caused by the periodic pressure wave propagation and reflection along the working chamber, and the pressure along the chamber is non-uniform when the sound speed is relatively slow compared with the chamber length in one compression cycle. A dimensionless ratio of chamber length and pressure wave travel distance is proposed to estimate the pressure distribution in the working chamber, based on which the flat section is prone to appear in large-scale compressors with low sound speed refrigerants like R134a. Some improvement directions were put forward to avoid efficiency losses, i.e., appropriately delaying the suction end angle and modifying the discharge port to match the pressure distribution.

Analysis of 3D Transient Flow in a High-Speed Scroll Refrigeration Compressor

In mobile devices such as aircraft and electric vehicles, due to limited space, there are strict requirements on the volume and weight of the compressor mounted on the vehicle. Therefore, high-speed scroll compressors have attracted more and more attention because of their small size and light weight. In this paper, the numerical calculations and analysis of the three-dimensional (3D) transient flows in a high-speed scroll refrigeration compressor were established and validated. Circumferential gas intake was used in the simulation. According to the actual compressor size, the mesh generation accurately considers clearances. The radial and the axial clearances were both set as 0.01 mm. A dynamic and high-quality hexahedral structured mesh was generated for the working chamber, and the problem of insufficient grid density in radial clearance was solved. When the rotational speed was set as 3000 rpm, 6000 rpm, and 9000 rpm alternatively, the difference in the volume efficiency of the simulation and the experiment results was below 6.3%. The results show that the higher rotational speed contributed to the greater pressure fluctuation in the compression chamber and the discharge process, and the over-compression phenomenon was more obvious. The maximum leakage velocity was 160 m/s, and the tangential leakage velocity was higher than the radial leakage velocity. Meanwhile, radial leakage velocity will increase significantly in high-speed operation mode. With the increasing rotational speed, the position of the maximum axial and tangential leakage velocity was closer to the start of the scroll. Therefore, the seal of the scroll starting part is very important in the design of a high-speed scroll compressor.

HIGH PERFORMANCE TECHNOLOGIES USED IN FUSHENG SCREW COMPRESSORS 
 AUTHORS

In the context of negative changes occurring in the planets biosphere, such as pollution of the environment and the atmosphere, global warming, and depletion of energy resources, increasingly high criteria are imposed on manufacturers of refrigeration equipment, the most important of which are: (a) enhancement in the energy efficiency of refrigeration equipment; (b) decrease of material consumption of refrigeration units, and (c) use of clean and safe materials and refrigerants.
 The Taiwanese company, Fusheng, has been one of the world leaders in the production of screw refrigeration compressors for several decades. The experts at the company are always working to enhance the manufactured equipment and implement the most cutting-edge technologies.
 Recently, the most effective steps in this area have been the advancement and mastering of the manufacturing of special two-stage low-temperature screw compressors of the SRT series, as well as the production of compact screw compressors with an integrated BSR series oil separator with a variable compression ratio and semisealed screw refrigeration compressors with a volumetric capacity of 85 m3/h to 1946 m3/h
 The SRT compressor series consists of six types, with a first-stage volumetric capacity of 120759 m3/h and a second-stage volumetric capacity of 50300 m3/h

An experimental study on the determination of a hermetic reciprocating compressor’s discharge and suction losses

The most popular approach to determine compressor losses is to generate compressor pressure-volume indication diagrams. The pressure-volume indication diagram of a novel hermetic reciprocating compressor for household refrigerators operating with R600a was experimentally obtained under American Society of Heating, Refrigerating and Air-Conditioning Engineers (54.4°C/−23.3°C) and additional specific working conditions of (40°C/−25°C), (25°C/−20°C) and (35°C/−15°C). Apart from most studies, experiments have been performed using a calorimeter. The alteration of suction and discharge pressures with crank angle of the investigated compressor was presented as both graphical and numerical information during condensation and evaporation, separately. As a result of the analyses, total compressor losses increased with decreasing the condensation pressure. These losses were 10%, 8.7%, 5.7% and 4.6% of the total work and they were observed at the same speed of 1300 rotation per minute (rpm) as the lowest one under all operating conditions. Besides, the suction line losses having the largest losses in the compressor were calculated as 50.1%, 50.9%, 64.9% and 67.9% of the total one, and it has been determined that they increased with increasing the condensation pressure. Due to the more complex design of the equipment in the suction line, the losses in this region were found to be higher than those in the discharge line, as expected.

Nonlinear Modeling of an Automotive Air Conditioning System Considering Active Grille Shutters

This paper expands upon the state of the art in nonlinear modeling of automotive air conditioning systems. Prior models considered only the effects of the refrigerant compressor and the condenser fan. There are two new aspects included here. First, we create a mathematical model for front-end underhood airflow, considering vehicle speed, condenser fan rotational speed, and active grille shutter position. In addition, we present a new model for the power consumption of the vehicle associated with aerodynamic drag caused by underhood flow, as well as a fan power model which accounts not only for changes in rotational speed but also changes in flow rate. The models developed in this paper are coded in MATLAB/Simulink and assessed for various vehicle driving conditions against a higher-fidelity vehicle energy management model, showing good agreement. By including the active grille shutters as a controllable actuator and the impact of underhood flow on vehicle drag and fan power consumption, control schemes can be developed to holistically target reduced energy consumption for the air conditioning system and, thus, improve the overall vehicle energy efficiency.

Simulation of refrigerant-lubricant two-phase flow characteristics and performance test in space compressor

The vapor-compression heat pump allows for lightweight heat-control systems and efficient heat emissions. It is considered to be the best choice for future space thermal control systems. To solve the problem of separation and compression deterioration of conventional positive-displacement refrigeration compressors in a microgravity environment, an innovative microgravity solution, mixing refrigerant and lubricant without oil separation, is proposed. A flow model in the compression chamber was developed and simulations were performed to investigate the effects of gravity and lubricant volume fraction on the flow characteristics of the refrigerant-oil mixture in a rolling rotor compressor. A modified compressor performance test bench was built and the effect of compressor speed on parameters such as power and heat dissipation was investigated experimentally. The results showed a maximum difference between the simulated and experimental values of compressor discharge temperatures of 9.16 %. Under microgravity conditions, a lubricant-refrigerant mixture with a volume fraction of less than 5 % can serve as the system working medium. The lubricant volume fraction at the outlet of a compressor cycle in normal gravity was 4.9 %, while it was 3.34 % in microgravity. As the compressor speed increased from 1500 to 5000 rpm, the compressor power increased from 15.5 to 64.5 W and the system heat discharge rate increased from 115.2 to 164.1 W. The system refrigeration coefficient of performance (COPc) decreased from 6.4 to 1.5, while that of heat dissipation, COPh, decreased from 7.4 to 2.5.

150USRT Class R-513A Refrigerant Two-Stage Centrifugal Compressor Design Point and Separation Point Flow Field Simulation Analysis

This study used computational fluid dynamics for low greenhouse effect refrigerant (R-513A) simulation analysis in the two-stage 150 USRT class oil-free centrifugal refrigerant compressor using integrated part load value (IPLV) and internal flow field. The compressor rotor speed and mass flow rate for the IPLV working conditions with various loads were planned using Stage 1 and Stage 2 simulations, respectively. The performance and flow field numerical simulation analyses for the two-stage centrifugal compressor is discussed. This study used Ansys-CFX software for numerical simulation analysis and the conservation form of a 3D steady-state Navier–Stokes equation set with the finite volume discretization method for computation. The computing mode produced better computing efficiency and flexible mesh setting using the k-omega (k-ω) model, which has better computational performance in the near wall boundary layer and low Reynolds number flow field (used as the turbulence model) for simulation. The R-513A refrigerant property setting was calculated using the Soave–Redlich–Kwong gas equation. This study discusses the shaft work, pressure ratio, and isentropic efficiency and also describes the main research findings with the meridional pressure, isentropic efficiency contour maps, and flow field velocity vector diagrams. According to the numerical simulation results, in Stage 1 and Stage 2 simulations, the isentropic efficiency produced the highest numerical results in the 75% load case, which are 88.19% and 89.06%, respectively. The isentropic efficiency decreased to 75.93% and 82.26%, respectively, in the 25% load case. The flow field velocity vector diagram shows that in the 25% load case, there was back-flow field distribution near the impeller shroud. The compressor performance was also analyzed.

Development of cryotherapy device using refrigerant compressor for decreased skin temperature

Cryotherapy is a commonly used technique in sports medicine and physical therapy for the treatment of acute injuries and pain management. The application of cold temperatures leads to a decrease in skin surface temperature, which can have several physiological effects on the body. This can help to reduce inflammation, swelling, and pain in the affected area. Cryotherapy can be administered using various modalities, but controlled continuous cold devices are widely used in cryotherapy treatment due to their accurate temperature control, especially when treating large joints. These devices work by pumping cold water alternately into a cooling pad that is wrapped around a patient's limbs. The aim of this study is to develop a cryotherapy device that regulates low skin temperature for effective physical therapy treatment. This will be achieved by utilizing a refrigerant compressor in combination with a remote source of chilled water that is circulated through a cooling pad placed on the treatment site. The results show that this device can control temperature from 20oC to 5oC with a fluctuation of ± 0.4oC at the cooling pad. A test study on 32 volunteers showed that the skin temperature in the knee area can drop to 15.1oC±1.7oC (95% CI, 18.6-11.1oC) after 30 minutes of applying a cooling pad at 10oC. The experimental cryotherapy results on the skin surface are consistent with the simulation test results, indicating that this device can be developed into a medical device that provides precise and continuous temperature control, thereby ensuring ease of use and maximum therapeutic benefit in the field of physical therapy.

An automated diagnosis methodology for manufacturing and assembly failures of refrigerator compressors on production line using vibration data

An automated diagnosis methodology for manufacturing and assembly failures of refrigerator compressors on production line using vibration data

Vibration-Based Measurement of Activated Cylinders in Reciprocating Machines

Vibration signals from rotating and reciprocating machines provide insights into machine health and operating parameters. Reciprocating machines often feature cylinder deactivation systems for increased efficiency. This article presents a vibration-based method for the detection of activated cylinders in reciprocating machines. Simulated compressor vibration signals demonstrate the effect of cylinder conditions on spectral-coherence and mean-envelope-spectrum (MES) estimates. Physical parameters of the mechanical system and the results of the simulations advise the proposed method. With an appropriately chosen region of interest (ROI), the MES-based indicator (MESbI) correctly identified the number of activated cylinders of a four-cylinder reciprocating refrigeration compressor in both field and laboratory test setups. A discussion section addresses measurement uncertainty and calibration, and provides an example application.

Automation of Temperature Measurement in Induction Motors of Hermetic Compressors Based on the Method of Temperature Rise by Resistance

Recent studies have proposed the use of artificial neural networks to establish a correlation between the cooling capacity of refrigeration compressors and the results of quick production quality tests. However, the temperature measurement method used in the tests reflects a high uncertainty in the estimated performance parameters, primarily because the measurement is performed on the compressor shell, which has large thermal inertia and does not accurately reflect the temperature changes observed during the tests. This study proposes a set of modules that allow the application of the method of temperature rise by resistance to estimate the winding temperature of the single-phase induction motor of the compressor in quick quality tests. The winding temperature is a better estimate of the temperature at which the refrigerant fluid enters the compression cylinder and its use solves many of the problems associated with the traditional method. Validation tests show that the proposed solution is capable of automating the measurement in a safe, agile, and metrologically more reliable manner than the method currently used in quick quality tests in the industry.

IMPROVEMENT OF VOLTAGE STRESS ON MOTOR CONTROL HARDWARE VIA OPTIMAL LOCATION OF RC SNUBBER CIRCUIT

While the increase in the customer failure rate in the consumer electronics sector affects the manufacturers negatively in terms of cost. It has also become one of the issues that cause customer loss and customer satisfaction. In addition to the economic losses, during the production and distribution of the spare parts and products that are changed at the customer's home due to the reliability problems experienced in the field, extra carbon emissions are released to the nature for this operation. For these reasons, it has become important to reduce the rate of customer failure. 
 With the increase in electronic components, the quality and reliability precautions that may occur in the electronic circuits, have become the subject of study today. As in many white goods products, it is advantageous to have variable speed motors in refrigerators due to energy efficiency and energy regulation issues. For this reason, the compressor of refrigerator comes to the forefront as the component that dissipates the highest power proportionally. With the use of variable speed compressors, the need for an electronic board with including power conversion and motor driving capability has arisen.
 In this paper, RC Snubber circuits have been studied in order to prevent quality problems that may occur due to high switching frequency in flyback converter topology, which is one of the DC-DC converters that provide isolation. The methods in the literature based on the location of the RC Snubber in the circuit and the determination of its related values were examined and experiments were made on the simulation program. At the same time, a test mechanism was set up on the variable speed compressor motor control card of the refrigerator and measurements were taken with the help of an oscilloscope. The measurements taken in the simulation program and the experimental environment were compared.