Non-condensable gasses such as air, hydrogen, nitrogen and hydrocarbons reduce the overall efficiency of refrigeration systems. The effects of non-condensable gasses, in a refrigeration system, increase the system operating pressures. These in turn negatively affect system performance. Increased compressor discharge temperature, higher energy costs, reduced system efficiency, leaks due to higher pressures, and increased wear on mechanical components are all negative consequences of non-condensable gasses in refrigeration systems.
The build-up of non-condensable gasses in the system can be attributed to several factors. These include inadequate system evacuation during service of system equipment, additions of refrigerant, leaks through external seals on equipment as well as refrigerant and oil decomposition.
Common indicators of non-condensable gasses in the system are excessively high condensing pressure or temperature and deviations in the pressure and temperature relationship at saturation conditions. This can be determined by checking the temperature and pressure relationship at a known point in the system where the refrigerant is saturated, such as the condenser drain legs or high pressure receiver, as illustrated in Figure 1. A higher temperature measured at this point, compared to the saturation pressure, indicates the presence of non-condensable gasses in the system.
Ammonia refrigeration systems can be robbed of efficiency due to the presences of non-condensables in the system. These gasses lower heat transfer in coils as they take up space that should be occupied by the refrigerant itself. This can result in an overall efficiency reduction. These gasses can also cause compressors to work harder than they should due to increased head pressures in the system. Overall the presence of non-condensables causes your ammonia refrigeration to work harder than it should.
For example, a 20 psi head pressure increase will result in more than 5% decreased system capacity.
Increased operating costs
The decreased efficiency caused by non-condensables will result in higher power requirements for your system and this additional power comes at a great expense.
Using the same example, a 20 psi head pressure increase will result in a 10% increase in energy consumption. For every 100 tons of capacity a system operating 6500 hours per year would result in $6300 of additional operating costs.
A safe and effective solution
The V300 Rapid Purger from Parker Sporlan’s Refrigeration Business Unit will safely and effectively remove these non-condensables from your system and restore your system to its peak operational efficiency. The V300 is the 3rd generation of purger technology from Parker and is based on years of experience and testing. The V300 uses both pressure and temperature monitoring combined with a proprietary algorithm to automatically remove the air from the system in a safe and effective manner. If you are working on a system that is showing signs of increased head pressure or decreased operational efficiency the V300 can restore your system to its best.
The V300 Rapid Purger also has the ability to monitor the ammonia loss history. This function calculates the amount of ammonia lost during a standard purge cycle using a proprietary algorithm developed by Parker. Our engineers worked with live ammonia systems, including our own Broadview Ammonia Test Facility, to develop this algorithm based on real world applications and conditions. The result is that the V300 Rapid Purger can now display the amount of ammonia lost as part of its standard history display. The ammonia loss history can be viewed by week, by day, and by point:
Ammonia loss by week
Ammonia loss by day
The ammonia loss history will make compliance and reporting even easier when using a Parker Sporlan Rapid Purger. For additional information on the V300 Rapid Purger please click here or call us at 800-506-4261.
Download the Parker Sporlan V300 Purger product bulletin here.
Article contributed by Drew Stock, business development manager, Sporlan Division of Parker Hannifin.
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