Redi Controls Inc.
161 RJ Parkway
Franklin, Indiana 46131 USA.
Redi Controls Inc.
161 RJ Parkway
Franklin, Indiana 46131 USA.
Operational Overview of Oil Separation & Refrigerant Cleaning
The OAM Purger (O-A-M is an abbreviation for Oil-Acid-Moisture) is designed to continually clean oil, acid and moisture from a chiller's refrigerant charge and return the oil to the chiller's compressor lubrication circuit, oil reservoir sump, where it belongs. OAM Purger's operation of oil separation and refrigerant cleaning is accomplished via a unique process utilizing the properties of gravity, heat and pressure exclusively to function. The OAM Purger does not utilize mechanical pumps of any type.
The OAM Purger's oil separation and refrigerant cleaning is accomplished by repeatedly extracting from the chiller evaporator (cooler) batches of oil-contaminated refrigerant, approximately 10 pounds, per each cycle. The oil-contaminated refrigerant is then heated via a distillation flexible band heater, which causes the liquid refrigerant to vaporize (boil-off) thereby distilling out contaminating oil. When the temperature of the accumulated distilled oil reaches 155 degrees F it is essentially pure oil, wherein it is automatically returned to the chiller's oil reservoir (sump).
The OAM Purger operates around the clock non-stop as long as power is applied, whether or not the chiller is operating, and cleans between 850 to 1250pounds of contaminated refrigerant weekly.
How the OAM Purger Works
The OAM Purger continually draws off a small quantity of refrigerant, typically 10 pounds at a time. The refrigerant is then distilled back to the chiller leaving the oil behind. The recovered oil is then automatically returned to the chiller's oil sump where it belongs. Acids and moisture are also removed from the refrigerant and oil during the process.
Because the purger operates 24 hours a day around the clock, regardless of chiller operating status, the refrigerant is permanently maintained in a virtual oil free state. This is true even in those situations where significant oil crossover occurs due to excessive oil seal wear.
The OAM Purger is a totally passive device that operates independently of the chiller and has no effect on chiller operation other than cleaning the refrigerant, saving energy and increasing capacity. Operation of the OAM Purger is accomplished, without an inductor pump, via a unique process utilizing gravity, heat and pressure exclusively to function.
The OAM Purger operates non-stop as long as power is applied, whether or not the chiller is operating, and cleans between 850 to 1250 pounds of contaminated refrigerant weekly.
The Three Operational Phases:
Phase 1 or Fill Phase: Oil contaminated refrigerant flows by gravity from the chiller evaporator into the OAM Purger distillation vessel.
Phase 2 or Distillation Phase: The Distillation Phase always follows the Fill Phase. During the Distillation Phase the flexible band distillation heater is energized heating the oil contaminated refrigerant causing the liquid refrigerant to vaporize (boil-off) pressurizing the purge vessel. When vessel pressure exceeds the pressure setting of a Distillation Pressure Regulator the regulator begins cracking open allowing over pressure to flow from the vessel to the lower pressure chiller evaporator (cooler). In the process, any entrained oil in the liquid refrigerant is distilled out and accumulated in the purge vessel. When the temperature of the accumulated distilled oil reaches 155 degrees F the distillation phase terminates and the Oil Return Phase is initiated.
Phase 3 or Oil Return Phase: During the Oil Return Phase distilled oil accumulated during the Distillation Phase is automatically transferred (pushed by vapor pressure maintained within the Distillation Vessel by the Distillation Pressure Regulator) from the purge vessel to the chiller's compressor lubricating circuit (oil reservoir).
It is common knowledge that oil build-up occurs in all centrifugal chillers. Oil invariably finds its way into the evaporator where it mixes with the refrigerant, degrading system efficiency and capacity. This occurs when the evaporator tubes become coated with oil, the heat transfer efficiency is retarded and drastically reduces the cooling effect.
In fact, recent studies have identified excess oil on the refrigerant side of a chiller as a leading contributor to chiller inefficiency, and that the problem is widespread.
In one study, ASHRAE Research Project 601-TRP, refrigerant samples were taken from 10 operating chillers and analyzed for oil content. All of the chillers were found to contain excess oil in varying amounts from 3% (enough to significantly degrade performance) to as high as 23%. According to one OEM, as little as 1% (by weight) of oil in refrigerant could result in as much as a 3% loss in chiller efficiency.
In our conversations with many companies with commercial and industrial HVAC cooling and air conditioning systems and industrial process cooling chillers we have learned that 15 to 20% or more oil concentration in the chillers refrigerant charge is typical. Thus, this could mean a 30 to 40% loss of capacity with a corresponding increase in energy consumption.
As you know, once oil gets into the chiller's refrigerant it's very difficult to get it back out. In the past, about the only way an oil-logged chiller could be fixed was to either remove and distill the refrigerant, or replace the charge with virgin refrigerant. In either case it was a very expensive process and it required a considerable amount of down time. As you are aware most centrifugal chiller applications simply cannot afford to have a chiller down, Period! Also utilizing the past methods, of cleaning or replacing the refrigerant charge, the fix was only temporary. The minute the chiller was placed back into operation oil contamination began all over again.
Advantages to the chiller owner...
1) The OAM Purger quickly cleans the chiller's refrigerant charge to only a trace level of oil.
2) Quickly restores chiller to peak operating efficiency.
3) Substantially reduces energy consumption saving the owner thousands of dollars in operating cost.
4) The OAM Purger pays for itself in 3 to 4 months. So, in effect, retrofitting an OAM Purger does not
really cost the owner anything. In fact, retrofitting with an OAM Purger is a financial investment
that keeps on paying dividends (in most cases thousands of dollars per month).
5) Reduces maintenance and helps prevent premature failure.
Every chiller truly needs an OAM Purger. All you need to do is refer to the results of the latest refrigerant analysis, and consider the benefits of retrofitting with an OAM Purger.
The OAM Purger retrofits to any existing high or low-pressure centrifugal chillers. Installation is easy and typically can be accomplished in about two days and consists of three 1/4" copper line connections and 120 Volt power supply.