Sizing Pipes, Pumps, and Control Valves Concurrently

Many systems contain both pumps and control valves, which makes the sizing process somewhat more complex.

Like sizing pipes and pumps or pipes and control valves concurrently, there are adjustments and estimations that must be made when sizing all three in parallel. The overall goal and considerations that must be taken into account are described in detail in those topics and will not be repeated here. Only the outline of steps will be presented for brevity.

Process Outline

Find the Approximate Pump and Control Valve sizes

  1. Model the pump(s) with the Pump Sizing option, fixing the flow to the desired amount.

  2. Model the Control Valve(s) with the appropriate settings.

    • If the control valve(s) are Flow Controls downstream of the pump(s) to be sized, temporarily set them to be Pressure Drop Control Valve with a setpoint equal to the minimum required pressure drop.

    • Any non-Pressure Drop control valves will require a Design Requirement of minimum dP/dH or maximum Cv/Open Percentage.

  3. Add the pump(s) and control valve(s) to one or several Engineering Libraries.

    • Attach a Cost Library to the Engineering Library if one does not already exist.

    • Create a Power vs. Cost Scale Table for the pump with estimated cost values.

    • Create a Cv vs. Cost Scale Table for the control valve with estimated cost values.

  4. Select the appropriate options in the Sizing Window.

    • The cost for the pump(s) and control valve(s) will only be included in the Objective if it is specified to be included in Size/Cost Assignments.

    • If there are several pumps or control valves that will ultimately be of the same type, they should be placed into Maximum Cost Groups.

  5. Run ANS.

    • Investigate the resulting pump size.

    • Update the Nominal Efficiency and NPSHR based on the result. Also update the cost information if necessary. If the pump accounts for a large portion of the overall cost, accurate values here are more important.

    • Repeat the process as necessary, until reasonable estimates for cost at the resulting operating point are obtained.

Compare Candidate Pumps

  1. Locate accurate cost information and pump curves for the candidates.

    • Incorporate these values into Engineering and Cost Libraries.

  2. Compare the sizing results for each candidate pump.

Select the two or three best candidate pumps and compare candidate Control Valves.

  1. If necessary, change Pressure Drop Control Valves back to Flow Control Valves.

    • This will require a Design Requirement of minimum dP/dH or maximum Cv/Open Percentage.

  2. Locate accurate loss and cost information for the candidate control valves.

    • Incorporate these values into Engineering and Cost Libraries.

  3. Compare the sizing results for each candidate control valve, under each candidate pump.