ECO operation combined with liquid injection (LI) for additional cooling
Depending on the operating conditions, even in operations with economiser (ECO) - for example in areas of high condensing and/or low evaporation temperatures - the use of additional cooling by means of liquid injection (LI) may be necessary. A relatively simple method is direct liquid injection (LI) into the profile area.
The additional components required include a solenoid valve in the liquid line (Solenoid valve in the liquid line) leading to the LI nozzle and a thermostat (Thermostat for solenoid valve). The thermostat opens and closes the solenoid valve as a function of the discharge gas temperature.
The compressors of the CSW65 .. CSW105, CSVW, CSH76 .. CSH96 series have no connection for liquid injection (LI) for the purpose of additional cooling.
For connections and shut-off valves see also:
- AT-320: Connections and shut-off valves for BITZER compressors
When operating with compressor module (IQ Module CM-SW), the module also controls the liquid injection, see:
- ST-150: Compressor module CM-SW-01 for screw compressors
Liquid injection in combination with refrigerant R717 (ammonia) only after consulting BITZER!
The ECO connection and LI injection connection on the compressor lead directly to the profile area.
Use only pipelines and system components which are
- clean and dry inside (free from slag, swarf, rust and phosphate coatings) and
- delivered with an air-tight seal.
Depending on their design, compressors are supplied with blanking plates on the pipe connections or shut-off valves. They must be removed before performing the pressure strength and tightness tests and commissioning the system.
The blanking plates are only designed to serve as a transport protection. They are not suitable as a separation between different system sections during the strength pressure test.
Additional connections for evacuation
For an optimal evacuation capacity, it is recommended to install generously-sized, lockable additional connections on the discharge and suction sides. Sections locked by check valves must have separate connections.
Risk of refrigerant loss!
Prior to commissioning the system, check newly mounted pipes for pressure strength and tightness!
Risk of compressor damage!
Generously sized filter dryers should be used to ensure a high degree of dehydration and to maintain the chemical stability of the circuit. Make sure to choose a suitable quality (molecular sieves with specially adapted pore sizes).
For systems with rather long pipelines or when brazing or welding without protective gas:
Install the suction-side cleaning filter (mesh size < 25 μm).
Make sure that pipes are fixed sufficiently
An incorrect installation may lead to very strong vibration of the pipework.
Risk of damages caused by vibrations!
Securely fasten each pipe.
Check the vibration behaviour during operation!
Observe the following for all connections retrofitted on the compressor:
Risk of refrigerant loss!
Check the thread.
Screw in the adapter carefully with the required tightening torque.
Test tightness before commissioning!
If the respective connecting valve is retrofitted or is removed when mounting the pipe:
Risk of refrigerant loss!
Check the threads.
Screw in the adapter carefully with the required tightening torque.
Test tightness before commissioning!