2. Product description
2.1 Outline of refrigerant R744
2.2 Optyma™ iCO2 condensing unit
R744 is an environmentally friendly refrigerant with the ozone depleting coefficent at “0” and a smaller global warming
potential. Refrigerant R410A is comparable with this in terms of the ozone depleting coefficient but has a higher global
warming potential. R744 has a higher pressure of 64 bar at the same temperature, it is approximately 4 times higher than
16.5 bar of R410A.
Caution of refrigerant R744
1. Refrigeration cycle operates at higher pressures.
As a result, it becomes necessary to change the airtight test pressure and setting pressures, including the airtight pressure,
withstanding test pressure, operating pressure, etc., for devices that constitute the refrigerating, and measuring instru-
ments and tools. It is necessary to change also the material and wall thickness of refrigerant pipe (Using K64 class standard
pipe).
Refrigerant leak detector needs to have a higher sensitivity.
2. Only use Condensing unit oils recommended by Danfoss.
Synthetic oil (ester oil) compatible with R744 is used.
Scroll-rotary type compressor
WARNING
Scroll-rotary compressor is prohibited to turn in reverse.
Contrary to conventional reciprocal type compressor which can rotate in both directions, it can rotate in one direction only
with the scroll-rotary compressor.
Scroll-rotary compressor becomes very hot
It is highly heated during and immediately after stop of operation. Special care must be taken during maintenance
and service.
Oil is retained at the high pressure side of scroll-rotary compressor.
Care must be taken particularly when charging or discharging oil during maintenance, service, or test run.
Optyma™ iCO2 combines our market leading expertise in condensing unit design with the unique benefits of stepless
inverter Rotary technology. The result is 20-30% higher energy efficiency in a flexible plug-and-play package.
The condensing unit includes following:
• Inverter Compressor ( Rotary)
• 2 parallel gas cooler (Coated fin and tube Heat exchanger)
• Unit controller
• 2 DC fan Assembly
• Receiver
• The condensing unit assembly is CE, PED certified CAT II
• This condensing unit controls its capacity by the speed control by means of inverter
• Compressor is connected to the inverter, and operated at variable speed. The inverter changes the power supply frequency
supplied to the compressor of which speed changes nearly proportional to this frequency. The capacity is controlled in
this way.
• Whether the load is high or low it is judged by detecting the low pressure (LP) of compressor. If the low pressure (LP) is
high, it is judged that the load is high so that the output capacity of condensing unit is increased.
• The speed control by inverter features that it allows to change the capacity more finely than the unit number control of
compressor. For this reason, it is better to install a plural number of evaporators, as much as possible, so as to control res-
pective liquid solenoid valves individually, for effective operation.
• Since the inverter is in the advancing phase, if an advancing capacitor is installed, the power factor drops in reverse. Never
install an advancing capacitor, because it may be broken.
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AB408540130380en-000102
© Danfoss | Climate Solutions | 2023.02
Application Guidelines
