Thermal loss analysis of hermetic compressors using numerical simulation

Posch, Stefan; Hopfgartner, Johann Wilfried; Dür, Lukas Albrecht; Eichinger, Martin; Stangl, Stefan; Almbauer, Raimund

doi:10.1016/j.applthermaleng.2017.11.104

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…Posch et al 6 characterized compressor losses in terms of entropy production and exergy loss for a household reciprocating compressor under a single operating condition. According to their location, the findings were segmented into losses.…”

Section: Introductionmentioning

confidence: 99%

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

Bacak

Pınarbaşı

Dalkılıç

2023

Proceedings of the Institution of Mechanical Engineers, Part E:

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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.

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Section: Introductionmentioning

confidence: 99%

“…Posch et al 6 examined the mechanical and thermodynamic losses of a hermetic reciprocating compressor under ASHRAE operating conditions. The losses of the compressor were represented as entropy production and exergy loss.…”

Section: Introductionmentioning

confidence: 99%

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

Bacak

Pınarbaşı

Dalkılıç

2023

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…Many studies have been published concerning simulation models and experimental methods for analyzing the effect of energy loss on the operation of a reciprocating compressor [8,9]. Santos et al [10] evaluated the efficiency related with leaks and viscous friction in the piston-cylinder clearance of an oil-free linear compressor, using the CFD model.…”

Section: Introductionmentioning

confidence: 99%

Development and Research of a Promising Pumpless Liquid Cooling System for Reciprocating Compressors

et al. 2023

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A new pumpless liquid cooling system for a single-stage two-cylinder reciprocating compressor has been developed from the analysis of work processes and cooling systems of reciprocating compressors, where one piston compresses and moves gas and coolant in the cooling system. The intensification of the coolant movement increases in the machine, which can reduce the temperature of the cylinder–piston group and increase the indicator efficiency and the compressor feed rate. A mathematical model of working processes in a reciprocating compressor and its cooling system has been developed on the basic fundamental laws of conservation of energy, mass and motion. A prototype was developed and tested to obtain new knowledge about the processes in the machine and confirm the assumptions made while developing the mathematical model. After a series of experiments, the influence of cooling on the working processes in a reciprocating compressor, the technical work carried out in each working process, the energy and consumption characteristics of a reciprocating compressor with a developed cooling system were established. There was a validation performed of the developed mathematical model of work processes in the machine and the assumptions made. According to the developed mathematical model of work processes, a numerical experiment was carried out, which established: the coolant flow rate decreases with an increase in discharge pressure and increases with an increase in the crankshaft speed when the discharge pressure changes from 0.4 MPa to 0.8 MPa, a decrease in the indicator isothermal efficiency due to the leakage and non-isothermal nature of the compression process, as well as a decrease in the return work in the process of reverse expansion, leading to a decrease in the indicator isothermal efficiency of more than 15%; due to the equalization of pressures in the gas cavities with an increase in discharge pressure, the coolant consumption is reduced by (15 ± 17)%; with an increase in the angular speed of the crankshaft from 800 rpm to 1500 rpm, the coolant flow rate increases by more than 2.5 times, this increase in coolant flow rate is due to an increase in hydraulic resistance due to an increase in gas velocity; in the range from 1000 to 1200 rpm, a maximum of the indicator isothermal efficiency and compressor feed rate is observed; maximum indicator isothermal efficiency and the supply ratio is observed at a coolant flow rate in the range from 800 mL/min to 900 mL/min.

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“…Silva and Deschamps described a model to predict gas leakage of the reed‐type valves of small reciprocating compressors at the condition of incomplete sealing, and they found that the leakage significantly reduced the compressor efficiency even for very small valve clearances. Posch et al conducted a comprehensive numerical investigation of the thermal losses of a hermetic compressor for refrigeration application, and they found that the cooling capacity of the compressor can be increased by 2.63% but the compressor coefficient of performance (COP) is only increased by 1.57%. Kerpicci et al investigated the effects of the oil viscosity on the performance of a reciprocating compressor, and they found that the low viscosity values affected the mass flow rates in particular.…”

Section: Introductionmentioning

confidence: 99%

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

et al. 2019

Int J Energy Res

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Summary An experimental test system including the oil circulation system and the gas circuit system has been designed and built to explore the effects of the lubricating oil flow rate on the performance of a single‐screw compressor, used in a portable natural gas liquefaction process. Outlet pressure, outlet volumetric flow rate, volumetric efficiency, and specific power rate are the parameters for evaluation of the energy performance of the single‐screw compressor. The experimental results indicate that the outlet pressure and outlet volumetric flow rate can be effectively increased by increasing the flow rate of the lubricating oil at different rotational frequencies and that a certain amount of lubricant oil is helpful to improve the volumetric efficiency. In terms of the specific power rate, the optimum oil‐gas ratios are 0.7%, 0.93%, and 1.79%, and the corresponding outlet pressures are 0.45, 0.45, and 0.48 MPa at the conditions of 50, 40, and 30 Hz, respectively.

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Thermal loss analysis of hermetic compressors using numerical simulation

Cited by 9 publications

References 16 publications

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

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

Development and Research of a Promising Pumpless Liquid Cooling System for Reciprocating Compressors

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

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