Standards And Certifications; Presentation - Intended Use; Design Data; Identification - Rating Plate (Fig. 1) - Arneg Globo PS 52 Serie Guía De Instalación Y Manejo

Globo
CO
Transcritical Rack
2
English

4. Standards and certifications

All the refrigeration unit models described in this user manual meet the essential safety, hygiene, and protection requirements
established by the following European directives and laws:

Machinery Directive 2006/42/EC

Electromagnetic Compatibility Directive 2014/30/EU

Low Voltage Directive 2014/35/EC;

Pressure Equipment Directive PED and subsequent modifications 2014/68/EU
A copy of the Declaration of Conformity of the product by filling in the form at: https://www.arneg.it/it/dichiarazione-
di-conformita-del-prodotto

5. Presentation - Intended use

CO2 refrigeration units are refrigeration racks consisting of multiple compressors of varying power connected to each other and
mounted on a frame. The system uses CO2 as a refrigerant in a direct expansion system to the evaporators, in order to obtain
both normal temperature (NT) and low temperature (LT) cooling and, if there are heat exchanges, the production of hot water.
The cooling capacity is produced by the refrigeration rack by means of subcritical and transcritical compressors in Booster
configuration.
A Booster configuration refrigeration system uses two-stage compression: the discharge of the first compression stage is sent to
the intake of the second compression stage to increase its pressure. The first compression stage provides the cooling capacity
for low temperature (LT) cooling, while the second stage provides the cooling capacity for normal temperature (NT) cooling.
The superheated steam that reaches the LT users is compressed by the LT compressors. It is then mixed with the superheated
steam coming from the NT counters and with the flash steam coming from the liquid receiver. At this point, the mixture enters
the NT compressors. The hot gas leaving the second compression unit is sent to the heat recovery (if any) and to the gas-
cooler.
At the gas-cooler outlet, the gas undergoes a first pressure reduction through the HPV valve and then it is sent to the liquid
receiver. Any steam is removed and sent to the NT compressors, while the liquid in the receiver is sent to both the NT and LT
users and, after a second pressure drop obtained thanks to a throttling device, it is vaporised by the heat absorbed from the
users (refrigerated counters or cold rooms). The cycle ends when the refrigerant, in the superheated steam state, is sent to the
compressors to be compressed again.
This operation is automatic and is adjusted by means of the electronic controllers for LT and NT which, by interacting with
appropriate pressure sensors, manage the main operating parameters of the system.
There is a secondary circuit for the oil return which, collected from the separator on the delivery line and stored in the oil tank, is
supplied to the compressors by means of electronic level regulators.
There are high pressure switches on the LT and NT compressors (calibrated at pressure values lower than the PS) which, in the
event of an excessive pressure increase caused by abnormal compressor operation, shut off the supply to the compressors
themselves.
On liquid receiver and circuit, there are safety valves to release the overpressure.
The refrigeration unit is supplied complete with all the elements necessary for correct operation such as: electrical power and
control panel, pressure transducers, pressure switches and safety devices.
Fig. 5 shows the operating diagram of the refrigeration unit.

6. Design data


Maximum Permissible Pressure (high pressure)

Maximum Operating Pressure (medium pressure):

Maximum Operating Pressure (low pressure):

Maximum Permissible Temperature (delivery line):

Minimum Permissible Temperature (intake line):

Refrigerant type (2014/68/EU):

7. Identification - Rating Plate (Fig. 1)

The refrigeration unit features a serial number plate with all the specific data. It is advisable to keep a copy of the data in the
system surveillance and maintenance office:
13) Trade name of the product
14) Product code
15) Serial number
16) Supply voltage – Number of phases – Supply frequency
17) Maximum current absorbed
18) Type of refrigerant gas
19) Year of manufacture
20) Reference temperature and pressure for the delivery circuit
21) Reference temperature and pressure for the liquid circuit
22) Reference temperature and pressure for the MT intake circuit
23) Reference temperature and pressure for the LT intake circuit
24) CE marking with identification number of the Notified Body, according to Directive 2014/68/EU.
18
Ps = 120 barg
Pset = 60 barg
Pset = 52 barg (60 barg) / 30 barg (60 barg)
Ts max = +150 °C
Ts min = -40 °C
R744 (CO ) - Group 2
2
05060203 00 12/2020