Piping Diagram
Samsung Electronics 207
Electronic Expansion Valve – EVI (EVI EEV)
ƒ Purpose
Control the EVI EEV to secure a subcooling degree in cooling mode.
Control the EVI EEV to optimize the performance in heating mode.
ƒ Concept
The EVI EEV is regulated thro
ugh 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 heating
mode.
The EVI EEV step is regulated to adjust the compressor discharge temperature (Td) to obtain
the target Td if additional performance is
required in the low temperature section while in heating mode.
ƒ Control specifications in detail
In case you need additional refrigerant f
low in the compressor at a low temperature heating, or if you can operate compressor effec-
tively by increasing the flow rate through the injec
tion, 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 th
e installation conditions such as
the long pipe installation or a high head.
In EVI ON mode, optimizes the performance improvement through the injection by c
ontrolling 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 Heating
EVI Bypass mode
ƒ Sub-cooling control : 20 K
(High pressure Saturated temp. – Liquid tube
temp.)
ƒ SH control
1. EVI Out – EVI In temp. > 10 K (priority)
2. Tdis = 90ఁ
EVI On mode
ƒ (EVI out temp. – EVI in temp.) control : 2 K
Remark
ఐIf 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.)
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