Danfoss FC 102 Design Manual

Also see for VLT HVAC Drive FC 102: Operating instructions Service guide Programming guide Installation guide Installation guide

Contents

reduced by 20%. This is because the flow is directlyproportional to the RPM. The consumption of electricity,however, is reduced by 50%.If the system in question only needs to be able to supply aflow that corresponds to 100% a few days in a year, whilethe average is below 80% of the rated flow for theremainder of the year, the amount of energy saved is evenmore than 50%.The laws of proportionalityIllustration 2.10 describes the dependence of flow, pressure andpower consumption on RPM.Q = Flow P = PowerQ1 = Rated flow P1 = Rated powerQ2 = Reduced flow P2 = Reduced powerH = Pressure n = Speed regulationH1 = Rated pressure n1 = Rated speedH2 = Reduced pressure n2 = Reduced speedTable 2.5 Abbreviations Used in Equationn100%50%25%12,5%50% 100%80%80%175HA208.10Power ~n3Pressure ~n 2Flow ~nIllustration 2.10 The Dependence of Flow, Pressure and PowerConsumption on RPMFlow :Q1Q2 =n1n2Pressure :H1H2 =n1n22Power :P1P2 =n1n232.7.4 Comparison of Energy SavingsThe Danfoss frequency converter solution offers majorsavings compared with traditional energy saving solutions.This is because the frequency converter is able to controlfan speed according to thermal load on the system andthe fact that the frequency converter has a built-in facilitythat enables the frequency converter to function as aBuilding Management System, BMS.Illustration 2.12 shows typical energy savings obtainablewith 3 well-known solutions when fan volume is reducedto i.e. 60%.Illustration 2.12 shows more than 50% energy savings canbe achieved in typical applications.130BA782.10DischargedamperLess energy savingsIGVCostlier installationMaximum energy savingsIllustration 2.11 The 3 Common Energy Saving Systems130BA779.110 60 0 60 0 60020406080100Discharge Damper SolutionIGV SolutionVLT SolutionEnergy consumedEnergy consumedEnergy consumedInput power %Volume %Illustration 2.12 Discharge dampers reduce powerconsumption somewhat. Inlet Guide Vans offer a 40%reduction but are expensive to install. The Danfoss frequencyconverter solution reduces energy consumption with morethan 50% and is easy to install.Introduction to VLT® HVAC D... Design GuideMG11BC02 Danfoss A/S © Rev. 06/2014 All rights reserved. 212 2