Commissioning of refrigerating systems
Refrigerator Commissioning – Refrigerant recovery system
Figure 115 typifies a portable refrigerant recovery unit now in use within the refrigeration industry.
The compressor is an open reciprocating type, driven by a 1.5 kW single phase drive motor. An oil separator is fitted in the discharge line. Oil return is by float control and a solenoid operated return valve, which is energized by [...]
Refrigerator Commissioning – Good refrigeration practice for CFC systems
It is a well known fact that an engineer required to work on an ammonia system will be very careful not to allow undue discharges of refrigerant because of its toxicity. Since CFCs are non-toxic it has been common practice to discharge them to atmosphere. This must now be regarded as malpractice and cease forthwith.
Evacuation
It [...]
Refrigerator Commissioning – Environmental impact of CFCs
Chlorofluorocarbons (CFCs) are chemical compounds which have been developed for use as refrigerants. Their molecular structure is based on either methane or ethane; one or more of the hydrogen atoms is substituted by chlorine or fluorine.
The CFC refrigerants soon replaced most other refrigerants except ammonia, which is still in use today. Other products made from [...]
Refrigerator Commissioning – Oil addition and removal
When the system has been fully charged and the controls set, the equipment is operated at average evaporating conditions. The compressor oil level must then be checked.
All new compressors receive an operating oil charge during manufacture, but this does not allow for oil trapped within components and controls and circulating with the refrigerant. This is [...]
Refrigerator Commissioning – Commissioning checks
When the system has been evacuated, the next step is to carry out a thorough leak test.
The system may then be charged with refrigerant. Irrespective of which method of charging is used, it must be remembered that the compressor is being operated for the first time. It will have been standing for a considerable period, [...]
Refrigerator Commissioning – Evacuation
It is imperative, with halogen refrigeration systems, that all traces of air, non-condensibles and moisture be removed. If this is not achieved then the presence of air or non-condensibles will cause abnormally high discharge pressures and increased temperatures, resulting in the conditions relating to high operating pressures previously explained.
Air in the system will also mean [...]
Refrigerator Commissioning – Contaminants
During installation the system should be kept as clean and dry as possible, with the least exposure to air. Avoid the entry of foreign matter such as solder fluxes, solvents, metal and dirt particles, and carbon deposits; the last are the outcome of soldering joints without passing a neutral atmosphere through the pipework.
Failure to take [...]