Euro Line compressor unit *FU* regulated EFU-1DO-5 HI421CC+CIMR-AC40023F

Frequency-controlled Dorin power racks operate using two semi-hermetic HI series compressors, where one frequency-controlled compressor takes the role of the master compressor and the second compressor is activated as necessary by the frequency converter. These units have been specially developed for use in refrigeration systems with variable refrigeration demand. The use of a Power Electronics frequency converter allows the main compressor to run continuously while optimally adjusting cooling performance to the current conditions. The partial load behaviour has been further optimised compared to the E-FU-1DO devices by dividing power across two compressors. These devices are therefore an energy-efficient and space-saving alternative to power racks with multiple compressors. The Dorin power racks are available in 5 different performance classes.

Refrigerants R134a, R404A/R507 can be used. The maximum frequency may be limited for air conditioning applications. Cooling power is regulated depending on the intake pressure. A Power Electronics frequency converter is used in combination with a pressure transmitter to control the power rack. This is mounted and thermally decoupled on the intake side and records the actual intake pressure value. The power rack controller regulates the cooling power of the rack so that the target value is achieved as closely as possible.

The frequency converter is included with the control box. Configuration is input via a display. The frequency convertor comes pre-configured. Only a small number of parameters must be changed to make changes to the refrigerant used and the place of use. The control box is mounted to the frame and wired. If there is a fault with the master compressor, then the 2nd compressor is automatically controlled by the FC. If the FC-controlled compressor runs at a minimal frequency for a longer period of time, an oil purge switch is activated. The operating mode switch allows manual activation of temporary emergency operation with a single compressor via an additional low pressure switch (for emergency operation, the bridges in the compressor terminal box must be reconfigured from delta to star configuration!!).

The FC also assumes sequential activation of the two compressors in order to ensure even loads. The control box issues an isolated release signal to control solenoid valves in the fluid line.
In the event of a system fault, this release is deactivated in order to prevent damage from fluid hammering when restarting the system.

All components are attached to a tough riveted steel profile frame. All parts of the frame are powder-coated. The power rack stands on the supplied rubber-bonded metal base. Refrigeration lines are conveniently grouped together at the rear and can be shut off. Power racks are fitted with an oil separator as standard in order to ensure reliable operation, even during a temporary minimal cooling load on the system. Attention: In unfavourable installation conditions (cold plant room, connected heat recovery system), re-condensation of refrigerant can occur in the oil separators. In such cases, the oil separator must be electrically heated.

• optimally adapt compressor performance to changing loads on the refrigeration system
• low minimum cooling power
• optimal temperature and quality for refrigerated goods
• minimal space needed due to compact design
• energy saving from better performance control in optimal evaporating temperatures
• standard components mean it is easy to service
• reduce the installed cooling power and thus the cost of investment by use of coincidence factor
• simple installation of a heat recovery systems using a common heat exchanger for all areas to be cooled

• Control box with Power Electronics frequency converter, installation and wired
• semi-hermetic compressor from Dorin with crankcase heater
• compressor shut-off valves
• fluid collector
• refrigerant dryer / inspection glass
• filling valve in the fluid line
• ball shut-off valve in the pressure, fluid and suction lines
• pressure transmitter, suction pressure -0.5 - 7 bar
• pressure transmitter, high pressure 0 - 30 bar
• high pressure monitor on each compressor, type tested
• low pressure monitor, type tested for emergency operation
• low pressure switch for emergency operation
• oil separator with inspection glass and shut-off valve in the return line, with electrical heating