IIR document

Self-sufficient Propane-CO2 cascade with two-phase thermosiphon - Simulation of an evaporating two-phase flow with variable heat transfer coefficient.

Number: 0036

Author(s) : SCHMID O., NITSCHKE T., MELITO E., GUND S., KAUFFELD M.

Summary

A thermal energy storage (ice storage) is to be charged by a natural circulation evaporator, also called a two-phase thermosiphon. When using the natural circulation evaporator, the heat transmittance coefficient from the freezing water to the refrigerant changes with the loading of the ice storage. For the correct design of such a system it is important to predict the pressure drop and the flow behavior. In order to use a minimum of refrigerant, the smallest pipe diameter should be calculated at which the thermosiphon can be operated even with the required ice thickness on the outside. In this paper, a simulation is described, whereby the flow patterns, the required pipe length and the pressure drop can be determined for different internal pipe diameters and increasing ice thickness. A variable length pipe coil is simulated. R-744 (carbon dioxide) is used as refrigerant. The design procedure is explained by means of an example application in which an ice storage system is calculated for a cascade refrigeration system inside a refrigerated container.

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Pages: 16 p.

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Details

  • Original title: Self-sufficient Propane-CO2 cascade with two-phase thermosiphon - Simulation of an evaporating two-phase flow with variable heat transfer coefficient.
  • Record ID : 30029670
  • Languages: English
  • Subject: Technology
  • Source: 15th IIR-Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 13-15th 2022.
  • Publication date: 2022/06/13
  • DOI: http://dx.doi.org/10.18462/iir.gl2022.0036
  • Document available for consultation in the library of the IIR headquarters only.

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