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The improvement of the compressor efficiency by reducing heat transfer.

Number: pap. 1168

Author(s) : COLMEK S.

Summary

Many ways are possible to improve the compressor efficiency, like the reduction of the mechanical losses through valve or bearings which represent from 20% to 30% of total electric consumption power on the compressor. Another way is to decrease the pressure drop through the compression circuit of the compressor, which can reduce the temperature variation through the compressor…etc. In our case of study, we will be interested in the heat transfer and pressure drop through the suction circuit In this paper, we will present the challenge done on the heat transfer reduction through the suction line of the CAJ4519Z compressors, in reducing from 10°C to 20°C the flow temperature through the suction line, and thus improve the cooling capacity by increasing density of the flow. Indeed, according to the mechanical conception of the compressor, the suction line and entering gas flow is in contact with the hot discharge line and flow through the cylinder head part. Thus, the thermal conduction phenomenon at this level heats up the suction gas and consequently the density of the refrigerant flow and compressor capacity is reduced. In this case study, the cylinder head is cast iron material, and separates the suction line (flow at 64°C) and the discharge line (flow at 115°C) by a wall thickness of 0.8cm. Consequently, the suction gas is warmed by the conductivity and increases the temperature between 10°C and 20°C depending on the operating condition. To reduce the conductivity phenomenon on the cylinder head part, a judicious material selection is done according to the Ashby methodology based on the conductivity coefficient, and a new concept of cylinder head is done. Before testing the new concept, CFD (Computational Fluid Dynamics) simulation calculates the improvement from the existing to the new cylinder head concept, and allows defining the position of the sensors. The laboratory test results confirm the simulation results. Thus, thanks to the thermal characteristic of the material and re design the cylinder head part, we can reduce the temperature and improve by 2% (average value) the cooling capacity of the compressor.

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Pages: 10 p.

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Details

  • Original title: The improvement of the compressor efficiency by reducing heat transfer.
  • Record ID : 30014159
  • Languages: English
  • Source: 2014 Purdue Conferences. 22nd International Compressor Engineering Conference at Purdue.
  • Publication date: 2014/07/14

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