CLIMAVETENTA W3000 Technical Information PDF herunterladen (Seite 16)

C0240111-06-07-GB

1.4.4 Modulating adjustment of screw compressors

With screw compressors, modulating adjustment is performed on the outlet probe.

Modulating adjustment is only available on “Bitzer” screw compressors.

set point

t [min]

Tout [°C]

B (increase)

C (decrease)

Figure 1.9: modulating adjustment for screw compressors

Reference is made to the figure

to the left:

The setpoint remains within a

dead area. If the temperature

also remains within this zone,

no change is made to the

number of active compressors

or their load percentages

(position of modulating

chamber).

When the temperature rises

above zone B following a

change in the system load, the

compressors are activated in

order to return the temperature

to the dead area.

Inside zone B, if the outlet

temperature derivative is

positive, compressor power is

increased in order to return the

temperature to the dead area

(ZN). The further away the

temperature is from the

setpoint, the greater the

increase is.

When the temperature falls below zone C following a change in the system load, the compressors are

either deactivated in order to return the temperature to the dead area.

Inside zone C, if the outlet temperature derivative is negative, compressor power is decreased in order to

return the temperature to the dead area (ZN). The further away the temperature is from the setpoint,

the greater the decrease is.

The amplitude of the neutral zone depends on the dynamic characteristics of the system and, in

particular, on the amount of water it contains and the load. The self-adapting algorithm is able to

“measure” system dynamics and calculate the minimum dead area in order to respect compressor

activation times and the maximum number of start-ups per hour.

When a second or subsequent compressor is switched on, the ones that are already running are forced to

a minimum, and the subsequent power increases/decreases are applied to all the compressors.

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Соколов Александр Викторович 11 Mar 2024 | 09:24:43

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CLIMAVETENTA W3000 Technical Information Seite 16

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