Introduction; Application - Danfoss AK-CC 750A User Manual

Application

AK-CC 750A controllers are complete regulating units which
together with valves and sensors constitute complete evaporator
controls for refrigeration appliances and freezing rooms within
commercial refrigeration.
Generally speaking they replace all other automatic controls
containing, inter alia, day and night thermostats, defrost, fan con-
trol, rail heat control, alarm functions, light control, thermo valve
control, solenoid valve, etc.
The controller is equipped with data communication and is oper-
ated via a PC.
In addition to evaporator control the controller can give signals to
other controllers about the operating condition, e.g. forced clos-
ing of expansion valves, alarm signals and alarm messages.
Advantages
• Control of 1 to 4 evaporator sections
• Adaptive superheat control ensures optimum evaporator usage
in all operational circumstances.
• Electronic injection with AKV valve or stepper valve
• Traditional temperature regulation using on/off or modulating
control of solenoid valve for both DX and indirect brine system.
• Weighted thermostat and alarm thermostat
• Defrost on demand based on evaporator capacity
• Appliance cleaning function
• Light control using door switch or network signal depending on
day/night operation
• Rail heat pulsing depending on day/night operation or dew
point
• Monitoring of door alarm and control of light/refrigeration
depending on location of door switch.
• Log function for registration of historical parameter values and
alarm modes.
Control
The controller's main function is to control the evaporator so that
the system constantly operates with the most energy-friendly
refrigeration.
A specific function for registration of the need for defrost will
adapt the number of defrosts so that no energy is wasted on un-
necessary defrosts and subsequent cooling-down cycles.
Adaptive defrosting
The AK-CC 750A includes an adaptive defrosting function. By
using the injection valves opening degree as mass flow sensor for
the supply of refrigerant, the controller can monitor ice formation
on the evaporator. If the load is too large for the standard defrost
programme, the controller initiates additional automatic defrost
cycles to eliminate the need for expensive service calls due to
iced-up evaporators.
SW = 1.2x
AK-CC 750A

1. Introduction

RS8HP102 © Danfoss 2018-09
Evaporator control of one, two, three or four evaporators
Control of cool or frost
room
Control of cool or frost
appliance
3