Designing and commissioning variable flow hydronic systems.

Author(s) : AVERY G.

Type of article: Article

Summary

The author argues in favour of variable flow water systems for hot or chilled water feeding multiple air coils. By using variable flow, pump energy can be minimised and capital cost decreased by omitting the bypass requirement of a constant flow, three way control valve system. Design and commissioning however must follow a different path. Two examples of design and commissioning principles for variable flow water systems are given. The main criteria is in a careful selection of control valves. Equal percentage two way valves should be used having a plug lift to pressure rise ratio that allows the top 20% of full lift to be used for balancing purposes. By this means, circuit balancing is simplified and the secondary system pump can be flow controlled to maintain the required pressure difference across the ends of the mains. D.W.H.

Details

  • Original title: Designing and commissioning variable flow hydronic systems.
  • Record ID : 1994-2471
  • Languages: English
  • Source: ASHRAE Journal - vol. 35 - n. 7
  • Publication date: 1993/07
  • Document available for consultation in the library of the IIR headquarters only.

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