Table Of Contents; Introduction - Danfoss EKC 326A User Manual

Introduction

Application
The controller can be used in systems with transcritical and sub-
critical cooling control systems where CO2 is used as a refrigerant.
The controller regulates the pressure in the gas cooler (condens-
er) so that the system achieves the optimal COP.
The controller covers the following:
• Transcritical CO2 refrigeration systems (booster, cascade, high
pressure)
• Transcritical CO2 heat pump systems
• Transcritical CO2 refrigeration systems with heat recovery
• Transcritical CO2 chiller systems
• Extra capacity in warm periods. An improvement in the system's
cooling performance can be achieved by displacement of the
set point ("extra compressor")
Advantages
• Maximum COP
The controller guarantees the system's maximum performance
by maintaining the optimal pressure in the gas cooler when
regulation takes place in the transcritical range.
• The controller will always optimise to a subcritical state.
• Regulating the receiver pressure based on the receiver pressure
reading
• Heat recovery with adjustable reference pressure, 0-10 V
• Optimum heat pump operation
System
The pressure in the gas cooler is controlled by the valve. Regula-
tion must have inputs from both a pressure transmitter PGC and
a temperature sensor SGC. Both must be fitted in the outlet im-
mediately after the gas cooler.
The valve is an ICMTS valve, which has been specially developed
for the pressure conditions that exist in a transcritical CO
The motor section of the valve is an ICAD actuator and is control-
led by a 0-10 V signal from the controller.
If it is necessary to maintain a constant receiver pressure, a valve
(ETS, CCM or CCMT) and pressure transmitter (Prec) can be in-
stalled. The gas from the receiver bypasses to the inlet side of the
high pressure compressor.
Functions
Maximum COP control
The controller maintains optimum pressure in the transcritical
range based on a pressure and temperature reading.
The reference line is defined with a point at 100 bar. The desired
temperature can be set here.
Subcooling
d T subcooling can be used in the subcritical range.
Contents
Introduction ....................................................................................................... 2
Examples ............................................................................................................. 4
Survey of functions .......................................................................................... 6
Operation ..........................................................................................................10
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system.
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Manual RS8FM602 © Danfoss 02-2016
Menu survey .....................................................................................................10
Connections .....................................................................................................11
Data .....................................................................................................................13
Ordering ............................................................................................................13
Appendix ...........................................................................................................14
EKC 326A