Hanbell RC2-100AF, Manual

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104
auxiliary cooling apparatus is recommended to lower discharge temperature, maintain proper lubricant
temperature and replenish cooling for motor coil.

Air cooled system

High compression ratio system such as heat pump, low temperature refrigeration system

High discharge temperature system such as heat recovery system

If compressors have to run at partial load below 50% continuously in a long term.

Any other heavy duty application
There are two type of additional cooling of compressor ( liquid injection and oil cooler ) that described separately
as below. The cooling capacity of additional cooling can be calculated by the HANBELL selection software or
manually. For manual calculation, consider the most extreme conditions to be expected during actual operations
i.e. minimum evaporating temperature, maximum suction gas super heat and condensing temperature.
Liquid injection applications
In areas with high condensing temperature and/or low evaporating temperature as in the limitation diagram,
additional cooling is required in order for the compressor to work properly. A relatively simple method of additional
cooling is direct refrigerant injection in the compressor either in the motor side or compression chamber side.
The purpose of installing a liquid injection system is to prevent the compressor from overheat. The system
installed an expansion valve with tube, piped between the liquid line and compressor for cooling down the
compression chamber and motor to ensure the continuous and safe running of the compressor. The suction
superheat should be controlled between 5K~10K for the application of air-cooled and heat pump chillers by
means of expansion valve devices. These devices can be adjusted by the stem of the expansion valve to control
the suction superheat by means of refrigerant flow rate. When the initial startup, the loading of the chiller is heavy
due to the high temperature of chilled returned water, so the liquid injection devices capacity should be selected or
calculated enough to reduce the overheat of the compressor.
Liquid injection applied with low temperature expansion valve
When the compressor applied in the low temperature system (E.T.
≦
-10°C) the compression ratio is high at this
condition, also the discharge temperature will be very high. There are two connectors for the liquid injection in the
compressor, one is in the motor side to cool down the motor temperature and reduce the discharge temperature.
The other is in the compression chamber side and its function is to reduce the discharge temperature and
increase the compression efficiency.
Liquid injection applied with high temperature expansion valve
Select the high temperature expansion valve, which can sense the discharge temperature with its remote bulb.
This can control the opening of expansion valve proportionally, and can reach the best cooling effect; it will control
the compressor discharge temperature at an optimal situation of around 80

C.