CO
2
NNEXT
rev.01
EN
78 / 293
3.
Description of the partly-completed machine
The partly-completed machine models that are the subject of this document are faired condensing units for
use in commercial refrigeration. The faired condensing units are systems for positive and negative refrigeration
where the heat can be disposed of into the environment.
The faired condensing units are compact, low noise systems, suitable for working outdoors.
The partly-completed machine is designed and optimised to work with CO2 (R744).
The operating modes can be transcritical or subcritical depending on the conditions of the external
environment.
The electronic control, with appropriate logics, allows the partly-completed machine to always operate in
conditions of maximum efficiency in different environmental conditions and cold demand. It also manages
lubrication and any alarms signalling them on the electronic control terminal and on any type of supervision.
Depending on the models, for the condensing unit, units can be provided with a single fan-motor, or with a
double fan.
The various models are equipped with the following refrigerator accessories:
x
BLDC compressor(s) driven by inverter;
x
control valves;
x
intermediate receiver;
x
dehydrating filter and liquid indicator;
x
on-board gas-cooler;
x
electrical panel with relative electronic control;
For the negative refrigeration models there is also a desuperheater (intercooler) incorporated in the gas-
cooler battery.
All models also have a casing heating element that prevents the accumulation of liquid in the lower area of
the compressor during downturn periods. The unit is always enclosed in a self-supporting housing made of
steel varnished with epoxy powder, and is equipped with electrical equipment with a main disconnecting
switch (the power supply wire that must be connected to the switch is not supplied).
The following variants are possible:
x
Only for TN/MT positive refrigeration;
x
Only for BT/LT negative refrigeration;
The compressors are managed by a dedicated inverter, which allows modulation of the capacity from 25 to
100%.
The compressor(s) of the partly-completed machine can be provided with a by-pass solenoid to facilitate
starting of the same. On the line, pressing each compressor, there is a non-return valve.
The machine is equipped with pressure switches and safety valves to address any malfunctions.
In addition there are: back-pressure valve (HPV) in general delivery after the gascooler, intermediate liquid
and gas separation receiver, a gas flash valve (VFL) to keep the pressure constant at the receiver itself (only
in certain configurations), a braze-weld liquid filter with relative indicator, liquid-intake heat exchanger (if
any), insulation of all cold parts, shut-off valves and service valves for easy maintenance.
An electric power panel with magneto-thermal switches and electronic control allows the power supply and
management of the entire gascooler system and intercooler (if any) included.
