Preventing from liquid migration and saving money -F. Faralli-
The compressor is the most stressed part in the
refrigeration system and there are several technical solutions to improve its
reliability.
One of the main problems faced by the compressor is the mixing of
liquid refrigerant into the oil.
When the compressor is located where the
ambient temperature is lower than any other part of the system, the liquid
refrigerant might migrate from the circuit to the compressor during off cycle
or during a long shut down. Whenever the compressor starts, the foam formation
could totally or partially remove the oil from the compressor.
The crankcase heater, which should be turned on when the compressor is off, increases oil temperature reducing the concentration of liquid refrigerant in the oil. This is one of the possible technical solutions to limit liquid migration.
Dorin introduced as optional the self-regulating heater that compared to the standard one adjusts the absorbed power depending on the temperature. In case the temperature of the crankcase is high, for example when the compressor has been just turned off, this heater will not start or will work with limited absorbed power reducing the power consumption.
Main advantages compared to the standard ones are:
- Up to 30% lower power consumption
- Constant power output when the power supply is between 120 and 400 V
- Longer lifetime
The plot below shows the differences in power
absorption between the standard (CH) and the thermal regulated crankcase heater
(TCH).
The TCH absorbs more power when it is turned on but after a starting transient period the absorbed power will be much lower than the standard CH offering higher efficiency and longer lifetime.