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Method for evaluating the energy efficiency of free cooling and refrigerating systems in hydraulically linked circuits.

Number: 0174

Author(s) : WAGNER S. R., HAUSSER S., BECKER M.

Summary

Operating energy-efficient refrigerating systems reduces energy consumption and greenhouse gas emissions. For the uniform evaluation of energy efficiency during real operation, the German specification VDMA 24247-7 (2021) defines five balancing boundaries (0-IV) for calculating the Total Coefficient of Performance (TCOP) and Total Energy Performance Factor (TEPF). For cooling supply, indirect refrigerating systems often use several subsystems consisting of chillers and free cooling units. These subsystems are usually hydraulically linked in brine and/or chilled-water circuits. Assessing the energy efficiency of individual subsystems offers an advantage in monitoring and optimizing the overall system. Up to this point, the VDMA 24247-7 (2021) has not provided a clear method on how to evaluate a free cooling unit or a chiller subsystem in hydraulically linked circuits. Therefore, this paper defines a method to evaluate the energy efficiency of subsystems in hydraulically linked circuits for VDMA balancing boundaries II and III. To calculate the TCOP and TEPF of subsystems, necessary allocation rules (based on thermal capacity) are given for shared electrically powered components. The method is applied to a real laboratory system with an integrated chiller and free cooling unit. For these subsystems, the results for the TCOP II and TEPF II are given for parallel hydraulic integration in brine and chilled-water circuits. Further system indicators are presented to show control optimizations that can be recognized from the TCOP II of the subsystems.

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Pages: 11 p.

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Details

  • Original title: Method for evaluating the energy efficiency of free cooling and refrigerating systems in hydraulically linked circuits.
  • Record ID : 30031705
  • Languages: English
  • Subject: Technology
  • Source: Proceedings of the 26th IIR International Congress of Refrigeration: Paris , France, August 21-25, 2023.
  • Publication date: 2023/08/21
  • DOI: http://dx.doi.org/10.18462/iir.icr.2023.0174

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