EDM SYSCREW AIR EVO HSE

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SYSCREW 380-1260 AIR EVO HSE
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MODE 4 – AUTO-FLOW CONTROL [AFC]:
Thismodeprovidesvariableowsystem,consistingoftheprimarycircuit/primary+secondarycircuit.
AFCmodeincludesthefollowingcomponents:
• Twopressuretransducersinstalledattheendsoftheheatexchanger(ΔP
EVAPORATOR
) factory installed.
• A dedicated system control, factory installed.
• A modulating bypass valve with actuator supplied loose (installation by the customer).
Theoptionoffersacompleteandpredenedpackage,guaranteeingsimpleselection,supplyandcommissioning.Inpar-
ticular, the unit includes an additional control system, equipped with an evolved algorithm, which interacts with the main
control of the unit.
AFCmodeprovidesfollowingadvantages:
• Thissolutionissuitablefortraditionalinstallationswithconstantwaterowandterminalunitsequippedwiththree-
way valves.
• Itreducestheoperatingcostoftheplant[OPEX].
• The system provides complete and reliable control of the system.
• When the compressor capacity is equal to zero, the pump speed will reduced automatically to save energy during low
occupancy periods.
• Abypass,whichensurestheminimumowacrosstheheatexchangerthereforepreventingtheheatexchangerfrom
freezing.
TheoperatingprincipleofAFCsummarizedasfollows:
• Once the chiller has reached the water temperature set-point, the control ensures to work continuously at the best
efcientpumpspeed.
• During transient periods to reach the chiller water temperature set-point (e.g start-up), the control optimizes the
pump speed to get the lowest power consumption.
• Theuserhasaexibilitytoxtherequiredoperatingheadfromthechillercontroller.
• Thepumpspeedcanreduceuntilitreachestheminimumallowableowrateontheheatexchangeroftheunit.
• Uponexceedingtheminimumallowableowthreshold,theby-passvalvewillopentriggeredbythefrequencydrive,
torecirculatetheowthatisnotrequiredbytheplant,butwhichisnecessarytoguaranteetheowrateminimum
to the exchanger
FIGURE4:GENERALSCHEMATICSFORAUTOFLOWCONTROL