RHOSS TCHEY 115 Instrucciones De Uso página 26

2. High precision: "Precision" Option
In this operating mode, the unit wor ks at a fi xed set-point and, thanks
to the deli ver y water temperature c ontrol and the evol ved regulation
logic, at a c apacity of between 50% and 100% it is possible to
guarantee an average fluctuati on fr om the water suppl y temperature
of approxi matel y ± 1.5°C from the s et-point value compared to an
average fl uctuation over time of approxi matel y ± 3°C, which is
normally obtained with standard return c ontr ol.
The "Precision" option thus guarantees precision and reliability for all
thos e applicati ons that require a regulator that guarantees a more
accurate constant water s upply temperature, and where there are
particular damp c ontr ol requirements . However, in process
applications it is al ways advisable to use a water buffer tank or a
greater s ystem water content to guarantee higher s ystem thermal
inertia.
s
s fluctuation
FC capacity
Unit with water buffer tank, 4 litres/kW i n the s ys tem and
return c ontrol.
Unit with water buffer tank, 2 litres/kW i n the s ys tem and
deliver y control with "Precision" AdaptiveFunction Plus
functi on
The chart illustrates the fluctuations of the w ater temperature from the
set val ue for the v arious c apacities, demonstrating how a unit with
delivery control and the AdaptiveFunction Plu s"Precision" func tion
guarantees greater water supply temperature precision.
ACM Autotuning compressor management
AdaptiveFunction Plu s enables the Y-Flow units to adapt to the s ystem they ar e ser ving, so as to always identify the best c ompressor operating
parameters in the different worki ng conditions .
During the initi al operating phases, the special "Autotuning" functi on enables the Y-Flow unit with Ad aptiveFunction Plus to estimate the ther mal
inertia characteristics that regulate the s ys tem dynamics. T he func tion, which is automaticall y acti vated when the unit is s witc hed on for the first ti me,
executes a number of s et oper ating c ycles, during which it proc esses the information r elati ve to the water temperatures. It is thus possible to esti mate
the physical c harac teristics of the s ystem and to identify the opti mal val ue of the par ameters to be used for the control. In t his phas e it must be
considered nor mal that the deliver y temperature drops by a few degrees, below the s et value s et, however remaini ng above the anti-freeze set.
At the end of this initi al auto-es timate phase, the "Autotuning" func tion r emains acti ve, making it possible to adapt the control parameters quickl y to
ever y change in the water circuit and thus in the s ystem water contents.
Virtual Tank: guaranteed reliability, even with water only in
the pipes pipe
Low water content in the s ystem can cause the chiller units/heat pumps
to be unreliabl e and can gener ate s ys tem instability and poor
perfor manc e. T hanks to the Virtual T ank functi on, this is no l onger a
problem. T he unit c an operate in s ys tems with j ust 2 litres/kW in the
pipes gi ven that the control is able to c ompensate for the lac k of inertia
specific to a water buffer tank, " muffling" the control signal, preventing
the c ompressor from switc hing on and off in an unti mel y fashion and
reducing the average fluctuation of the s et-point value.
T
14
12
10
8
6
4
2
0
2000 3000
T
t
FC
T1
The gr aphics s tates the different trends of the temper ature of the
water leavi ng the chiller taki ng i nto consi derati on use c apacity
of 80%. It is possible to obs erve the trend of the temper ature for
the unit i n which, as w ell as the AdaptiveFunction Plus l ogic, the
Virtual Tan k functi on is active. It is less hysterical and s tabl e through
ti m e with av erage temperature v alues closer to the w ork set-point with
respect to a unit without the Virtual T ank functi on. It is also possible to
observe that in the unit with AdaptiveFun ction Plus and Virtual T ank
the c ompressor turns on l ess ti mes in the s ame ti me interval with
obvious advantages from a s tandpoint of electrical c onsumption and
system reliability.
26
4000 5000 6000 7000
Water temperature (°C)
Time (s)
Set-point temper ature
Deliver y temperature with Virtual Tank
Deliver y temperature without Virtual Tank
SECTION I: USER
T1
t
8000 9000