Piping DiagramSamsung Electronics 207Electronic Expansion Valve – EVI (EVI EEV)ƒ PurposeControl the EVI EEV to secure a subcooling degree in cooling mode.Control the EVI EEV to optimize the performance in heating mode.ƒ ConceptThe EVI EEV is regulated through PD control to secure the target subcooling degree in cooling mode.The EVI EEV step is regulated through PD control to enable operation according to the target EVI SH (superheat) degree in heatingmode.The EVI EEV step is regulated to adjust the compressor discharge temperature (Td) to obtain the target Td if additional performance isrequired in the low temperature section while in heating mode.ƒ Control specifications in detailIn case you need additional refrigerant flow in the compressor at a low temperature heating, or if you can operate compressor effec-tively by increasing the flow rate through the injection, it controls the EVI EEV in the EVI ON mode status.In addition, in case of cooling, it controls EVI EEV when needs super cooling in order to deal with the installation conditions such asthe long pipe installation or a high head.In EVI ON mode, optimizes the performance improvement through the injection by controlling the SH as 2 K and 5 K to EVI EEV.When there is need of sub cooling in cooling mode, it controls the degree of sub cooling as 20 K.EVI mode Cooling HeatingEVI Bypass mode ƒ Sub-cooling control : 20 K(High pressure Saturated temp. – Liquid tubetemp.)ƒ SH control1. EVI Out – EVI In temp. > 10 K (priority)2. Tdis = 90ఁEVI On modeƒ (EVI out temp. – EVI in temp.) control : 2 KRemark ఐ͑ If comp discharge temp. is abnormally high, open EVI EEV to decrease the discharge temperature.7-3 Functions (cont.)7-3-2-1 Actuator (cont.)7-3-2 Control (cont.)
