{"action":"closed","issue":{"url":"https://api.github.com/repos/NREL/EnergyPlus/issues/4950","labels_url":"https://api.github.com/repos/NREL/EnergyPlus/issues/4950/labels{/name}","comments_url":"https://api.github.com/repos/NREL/EnergyPlus/issues/4950/comments","events_url":"https://api.github.com/repos/NREL/EnergyPlus/issues/4950/events","html_url":"https://github.com/NREL/EnergyPlus/issues/4950","id":84053132,"number":4950,"title":"VRF defrost power calculation problems","user":{"login":"EnergyArchmage","id":8754769,"avatar_url":"https://avatars.githubusercontent.com/u/8754769?v=3","gravatar_id":"","url":"https://api.github.com/users/EnergyArchmage","html_url":"https://github.com/EnergyArchmage","followers_url":"https://api.github.com/users/EnergyArchmage/followers","following_url":"https://api.github.com/users/EnergyArchmage/following{/other_user}","gists_url":"https://api.github.com/users/EnergyArchmage/gists{/gist_id}","starred_url":"https://api.github.com/users/EnergyArchmage/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/EnergyArchmage/subscriptions","organizations_url":"https://api.github.com/users/EnergyArchmage/orgs","repos_url":"https://api.github.com/users/EnergyArchmage/repos","events_url":"https://api.github.com/users/EnergyArchmage/events{/privacy}","received_events_url":"https://api.github.com/users/EnergyArchmage/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/NREL/EnergyPlus/labels/Defect","name":"Defect","color":"e11d21"},{"url":"https://api.github.com/repos/NREL/EnergyPlus/labels/EnergyPlus","name":"EnergyPlus","color":"c7def8"},{"url":"https://api.github.com/repos/NREL/EnergyPlus/labels/S1%20-%20High","name":"S1 - High","color":"e11d21"}],"state":"closed","locked":false,"assignee":{"login":"EnergyArchmage","id":8754769,"avatar_url":"https://avatars.githubusercontent.com/u/8754769?v=3","gravatar_id":"","url":"https://api.github.com/users/EnergyArchmage","html_url":"https://github.com/EnergyArchmage","followers_url":"https://api.github.com/users/EnergyArchmage/followers","following_url":"https://api.github.com/users/EnergyArchmage/following{/other_user}","gists_url":"https://api.github.com/users/EnergyArchmage/gists{/gist_id}","starred_url":"https://api.github.com/users/EnergyArchmage/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/EnergyArchmage/subscriptions","organizations_url":"https://api.github.com/users/EnergyArchmage/orgs","repos_url":"https://api.github.com/users/EnergyArchmage/repos","events_url":"https://api.github.com/users/EnergyArchmage/events{/privacy}","received_events_url":"https://api.github.com/users/EnergyArchmage/received_events","type":"User","site_admin":false},"milestone":{"url":"https://api.github.com/repos/NREL/EnergyPlus/milestones/1","html_url":"https://github.com/NREL/EnergyPlus/milestones/EnergyPlus%208.4.0","labels_url":"https://api.github.com/repos/NREL/EnergyPlus/milestones/1/labels","id":1229491,"number":1,"title":"EnergyPlus 8.4.0","description":"Public release of EnergyPlus 8.4.0","creator":{"login":"Myoldmopar","id":849824,"avatar_url":"https://avatars.githubusercontent.com/u/849824?v=3","gravatar_id":"","url":"https://api.github.com/users/Myoldmopar","html_url":"https://github.com/Myoldmopar","followers_url":"https://api.github.com/users/Myoldmopar/followers","following_url":"https://api.github.com/users/Myoldmopar/following{/other_user}","gists_url":"https://api.github.com/users/Myoldmopar/gists{/gist_id}","starred_url":"https://api.github.com/users/Myoldmopar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Myoldmopar/subscriptions","organizations_url":"https://api.github.com/users/Myoldmopar/orgs","repos_url":"https://api.github.com/users/Myoldmopar/repos","events_url":"https://api.github.com/users/Myoldmopar/events{/privacy}","received_events_url":"https://api.github.com/users/Myoldmopar/received_events","type":"User","site_admin":false},"open_issues":129,"closed_issues":37,"state":"open","created_at":"2015-07-28T14:11:03Z","updated_at":"2015-08-26T13:37:30Z","due_on":"2015-09-30T06:00:00Z","closed_at":null},"comments":10,"created_at":"2015-06-02T14:40:15Z","updated_at":"2015-08-26T13:37:30Z","closed_at":"2015-08-26T13:37:30Z","body":"While conducting a study of VRF systems, the following issues where found in VRF defrost power calculations.  The model is not useable for defrost systems based on reverse cycle. \r\n\r\n1.  \"Reverse cycle\" and \"timed\" are not supported in code logic.  Defrost power always comes out zero.  the following is around line 760 in HVACVariableRefrigerantFlow.cc, but there is no logic to handle the case of Timed control. \r\n\r\nif ( VRF( VRFCond ).DefrostStrategy == ReverseCycle && VRF( VRFCond ).DefrostControl == OnDemand )\r\n\r\n 2. OnDemand power calculation is missing run time fraction term and does not agree with engineering reference.  Found that when using Reverse cycle with On Demand, the defrost power was too high, even higher that the normal VRF heating power consumption.  Defrost power should be well below heating power, maybe less than 10%.   The engineering reference includes a RTF term, but the code does not have that term.\r\n\r\n\t// this next equation is missing RTF term that shows in Eng Ref\r\n\r\n\tVRF( VRFCond ).DefrostPower = DefrostEIRTempModFac * ( VRF( VRFCond ).HeatingCapacity / 1.01667 ) * FractionalDefrostTime;  "}}