Daikin Tewis ECO2SMART Handleiding pagina 53

3.2. Operation

The integrated sub-cooling system will be controlled by:

• An expansion valve (EV1), which controls the reheating at the outlet of the HX1 heat

exchanger. The control must be carried out using the values indicated by the temperature sensor

T10 and pressure transducer P10.

• A compressor rack (ECO2), which will change the suction pressure and thus the evaporation

pressure in HX1, depending on the temperature at a point in the discharge line (T2 or T3 or T5).

The overall operation of the rack will remain the same as if it were not using subcooling. In this case,

the control of the discharge line, carried out using the HP expansion valve working as back-pressure,

should be performed from the values indicated by temperature sensor T2.1 and pressure transducer

P1.1, and this will adjust its operation with respect to the refrigerant conditions at these points.

This system will be able to work in one or the other mode by means of a selector which will give 2 digital

signals:

1- One digital signal selector can be activated for the plant to work as an ECO2 system. When the

system is to be operated in "subcooling mode", the system can only be operated in 1 way, using

the EV1 valve and the ECO2 compressors with variable suction pressure (MV1 closed).

2- When a digital signal selector is activated to work as parallel compression, the expansion valve

EV1 must be closed, MV1 open and the ECO2 compressors will switch to work with a pressure

SETTING set by the ECO2 controller.

3- In the event that a selector is placed in a position other than the previous two positions, the

system will stop operating so that expansion valve EV1 must be closed, MV1 open and the ECO2

compressors must be stopped.

If Heat recovery is requested "Heat RHX request" → To calculate the compressor suction pressure, it

should be possible to select a temperature sensor other than the one used for normal operation (T2,

T3 or T5) and thus to select another of these sensors to calculate the suction pressure as required (T2,

T3 or T5). For example, for normal operation T2 will be taken into account but when the digital heat

recovery input is activated T3 will be used (when there is GC by-pass).

When heat recovery is no longer requested, the temperature sensor will remain the one selected to

control the system without heat recovery (T2 in this example).

Consideration will have to be given to the option chosen for the type of heat recovery. If it is climate, the

AC part should be included in the COP as well (IT or HT compressors). All energy uses of the rack are taken

into account when calculating the overall COP.

We will have a reduced SET DO signal for operation as a parallel compressor in Free Advance. This

reduced SET will only be available in racks with a main control unit that allows the SET of the vessel to

be changed from an external digital signal. This signal must be activated whenever the ECO2SMART

system is operating in PARALLEL MODE and the signal must be used in the main control unit to change

in the main control unit to change the pressure SET of the vessel when the system is operating in

PARALLEL MODE.

GENERAL NOTE:

- When ECO2 MODE or PC MODE compressors are stopped → Valve MV1 must be open.

- When ECO2 MODE compressors are running →Valve MV1 must be closed.

- When PC MODE compressors are running → Valve MV1 must be open.

C/ Sir Alexander Fleming, 7 _ 46980 Paterna (Valencia) SPAIN info@tewis.com www.tewis.com (+34) 963 13 42 02

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