Hitachi YUTAKI S80 Series Technical Catalogue page 24

2. Features and benefits
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Concept of SMART cascade cycle
The normal cascade cycle would work continuously using two single-stage cycles; the innovative YUTAKI S80 SMART
cascade cycle allows to take advantage of the best possible performance depending on the water outlet temperature re-
quired.
Thereby, when the installation would require low water outlet temperatures, only one cycle will work (R410-H2O) whereas
that when the installation would require high water outlet temperatures, the two cycles will be activated (R410A-R134a and
R134a-H2O).
This control is possible by the actuation over the solenoid valves (SV1 and SV2). When the unit requires working with only
one cycle the SV1 remains ON and SV2 OFF, whereas that when the installation requires working with the cascade cycle
the SV1 pass to OFF and SV2 pass to ON.
1 cycle operation
Air
R-410A
(SV1)
ON
(SV2)
OFF
R-410A
R-134a
R-134a
H O
2
The innovative SMART cascade cycle results in a better COP than cascade conventional cycles, because it leverages the
best working conditions for any moment.
COP
24
TCGB0075 rev.0 - 11/2012
R-410A
H O
2
1 cycle operation
2 cycles operation
Differential
2 cycles operation
Air
R-410A
(SV1)
OFF
(SV2)
ON
R-410A
R-134a
R-134a
H O
2
W a t e r o u t l e t
temperature (ºC)
R-410A
H O
2