7 ADAPTIVE
ECH 200BD is a special model of the ECH 200 line that features extremely versatile characteristics and features, particularly
suited for small plants.
These are:
• Adaptive function
• Fan control in Defrosting mode
Antifreeze function with heat pump, depending on water pump and heat pump.
7.1 Adaptive function
Chillers are generally equipped with water accumulation tanks.
These provide the thermal inertia required to prevent the compressors from being frequently started or switched off when
the request of heat for the rooms to be cooled is low (frequent start and switching off operations influence the lifecycle of
compressors).
In some cases, the setting of safety limits for the start and switching off operations can delay the start of the compressors
as compared to the requests of the regulation algorithm, thus reducing the efficiency of the whole system.
Example: if a chiller is designed to supply 10 fan coils and only one of these chillers is running in Cooling mode, the
interval of time during which the compressor is expected to stay on is low; in addition the need of complying with the
safety limits would cause an increase of the water temperature above the set point determined by hysteresis.
Accumulation tanks would increase the thermal capacity and provide the inertia required to increase the running time,
though resulting in higher costs and in the need for increasing even the minimum size of the unit.
The Adaptive function, which changes the set points and hysteresis, electronically simulates the inertia of a water
accumulation container, thus also limiting its use.
7.1.1 Adaptive function: regulator
It is useful to remember that the start and switching off operations of compressors must comply with the standards of
safety limits.
The function analyses the actual running time of the compressor (ET) comparing it with the minimum running time that
has been set (MT).
Parameters
• C01 Compressor OFF-ON time
• C02 Compressor ON-ON time
• C08 Enables the Adaptive function
• C09 Set block in Cooling mode
• C10 Set block in Heating mode
• C11 Offset constant
• C12 Reset time for increases
• C13 Proportional Part Offset Coefficient
The minimum time (MT) is represented by the difference between the ON/ON (C02) and the OFF/ON parameter (C01):
• MT = C02 – C01
The actual running time (ET) is automatically registered by the unit.
7.1.2 Set point offset (for ET<MT)
The ON set point is changed by a value equivalent to the adaptive offset (AO) according to the formula shown below,
when the compressor is switched off:
• AO=((MT – ET)* C13) + C11
That is
• AO=((C02– C01 – ET)* C13) + C11
• The set point is reduced in “Cooling” mode: SET(1) = SET(COO) – AO(1);
SET(2) = SET(1) – AO(2)
and so on
• The set point is increased in “
Heating” mode: SET(1) = SET(HEA) + AO(1);
SET(2) = SET(1) + AO(2)
and so on
The index associated to the set point and offset values refers to the compressor cycle, after which all variables are
updated. The updated values are then used for the next cycle.
“SET(COO)” and “SET(HEA)” are the original set point values (for example those entered from the keyboard with menus
SET/COO and /HEA).
Minimum time
Actual time
Adaptive offsets
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