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Highly efficient large ammonia systems with very low refrigerant charge.

Number: 0116

Author(s) : VESTERGAARD N. P., SKOVRUP M. J., KRISTOFERSSON J.

Summary

Ammonia pump circulating systems are the dominant system type for large industrial installations. These systems are well-known over decades as very effective, flexible, easy to install, operate and easy to defrost. However, these systems typical requires large ammonia charges.
In classical pump circulating systems, the circulating rate is not controlled, but set to a given rate, sufficient for all operating conditions and load variations.
Ammonia direct expansion systems are not very common in large industrial systems. The classical superheat-controlled expansion valve requires a relatively high superheat to ensure stable conditions and avoid liquid in the suction line.
The paper is focusing on:
• Measuring principle for determining the evaporator outlet vapor quality in direct expansion systems, method for controlling the expansion valve, system benefits, system requirements and limitations.
• Measuring principle for determining the circulating rate in pump circulating systems, method for controlling the control valve in the liquid feed line, system benefits, system requirements and limitations.
• Discussion on the charge reduction potential in classical pump-circulating systems vs. pump circulating systems with controlled circulating rate on evaporators designed for low circulating rates.
• Discussion on the charge reduction potential in classical pump circulating systems vs. direct expansion systems with superheat or “slightly wet” return lines.

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Pages: 8 p.

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Details

  • Original title: Highly efficient large ammonia systems with very low refrigerant charge.
  • Record ID : 30029718
  • 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.gl2022.0116
  • Document available for consultation in the library of the IIR headquarters only.

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