While my last series of columns explored liquid subcooling in a refrigeration system, this article will compare subcooling amounts in a refrigeration system incorporating an overcharge of refrigerant, a dirty condenser, and air in the system.
The amount of condenser subcooling needed is system dependent. The more pressure drops — friction and static — associated with the lines and accessories that carry the liquid in the system, the more need there will be for liquid subcooling to prevent liquid line flash gas.
Condenser subcooling ensures that there is a liquid seal at the condenser’s bottom so the liquid line or receiver will not be fed with vapors. This condition prevents any noncondensables, like refrigerant vapor or air, from leaving the condenser’s bottom and entering the receiver or liquid line.
Oil separators are essential on low and ultra-low temperature refrigeration systems and on large air conditioning systems up to 150 tons. Most compressor manufacturers require oil separators on all two-stage compressors.
Megohmmeters (meggers) are electrical meters used to check the resistance and condition of the motor windings and the condition of the refrigeration and oil environment around the motor windings. A megger is nothing but a giant ohmmeter that creates a very large dc voltage (usually 500 volts dc) from its internal battery.
Since the tax credit program became available, all types of geothermal options have been on the minds of the building community. The earth loop, often referred to as the refrigerant loop, may be installed in three different configurations: diagonal, vertical, and horizontal.
Many servicemen experience service calls where the compressor has both a low head pressure and a high suction pressure. There are three main reasons why a compressor will simultaneously have a low head pressure and a high suction pressure.