Emerson Copeland EazyCool OME-4MTL-09X, Инструкции по применению

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26 C6.1.11/0718-0619/E
Parameter Description Level Min value Max value
Factory
setting
SPF1
Differential to be subtracted from
the compressor setpoint
Pr1 0K 20K 8K
SPF2
Compressor frequency during
pumpdown
Pr1
0%
(min speed
25 Hz)
100%
(max speed
60 Hz)
0%
SPF3 Pumpdown maximum time Pr1 0 min 25 min 3 min
SPF4 Automatic pumpdown Pr1 yes
SPF5 Pumpdown offset Pr2 0°C 40°C 20°C
Table 16: Pumpdown parameters
2.10.2 Pumpdown mode
The pumpdown function of the CO
2
refrigeration unit does not work in the same way as in units using
standard refrigerants. Based on the ambient temperature and the compressor setpoint, the controller
calculates two different pumpdown setpoints:
▪
setpoint based on ambient temperature = T
Amb
– SPF5
▪
setpoint based on compressor setpoint = SETC1
– SPF1
The lowest pumpdown setpoint will always be applied. The following diagram illustrates the controller
logic:
Figure 33: Controller logic for the pumpdown function
NOTE: The pumpdown setpoint will never be lower than what parameter RC02 allows.
2.10.3 Fan speed / gas cooler control
2.10.3.1 Subcritical operation
For gas cooler outlet temperatures typically below 27°C ( AIC7 < GC1 - GC2) , the system operates
in subcritical mode.
▪
The CO
2
refrigerant condenses inside the gas cooler (condenser).
▪
The condenser outlet temperature is read by the probe AIC7 , which defines the fan speed.
▪
The gas cooler valve HPV will keep a certain sub-cooling of the refrigerant (about 2-3K) in order
to create pressure differential between the gas cooler and the flash tank.
▪
The fan speed setpoint is +5°C with a proportional band of +5K, ie, down to 7.5°C, the fan will
always run at full speed, unless the ambient temperature goes down below 12°C. In this case
the fan speed will be reduced. At an ambient temperature of -15°C the maximal fan speed is
reduced down to 50%.
SETF1 Condenser Circuit 1 setpoint
Range : +5°C to +25°C
Unit : [°C]
-18°C < 0°C
Controller will perform
pumpdown down to -18°C
Ambient condition:
T
Amb
= 20°C
SPF5 = 20K
Compressor setpoint:
SETC1 = -10°C
SPF1 = 8K
Pumpdown setpoint based
on ambient temperature:
T
Amb
– SPF5 = 0°C
Pumpdown setpoint based on
compressor setpoint:
SETC1
– SPF1
= -18°C