Critical applications like military, medical, laboratory instruments, electric vehicles, and data centers all require solutions with a long life, low maintenance, and a long mean time between failures. A properly designed and manufactured vapor compression system will have a life expectancy between 70,000 and 100,000 hours MTBF. The primary moving part in a vapor compression system is the compressor which, in the case of a rotary design can revolve at up to 6500 rpm. All refrigeration system compressors used by Aspen Systems have been properly vetted and designed. A well-designed, properly charged, vapor compression circuit will last for 15-20 in a household application or 100,000 hours in an industrial/military environment. These systems, when properly designed, will typically outlast the systems they are integrated into.
This is not sufficient to guarantee long life and consistent performance. The choice of good components is necessary for a long-life, reliable system, but it is not itself sufficient to guarantee long-term performance. The primary root cause of all refrigeration system failures can be traced not to the compressor, but in 99% of the cases, to a lack of care in the design and manufacture of the refrigeration circuit.
- Too low of a refrigerant charge. This can lead to the compressor being overworked, compressor overheating, and eventual system failure.
- Too low quantity of oil in the system. This can lead to a lack of efficiency, and excessive wear in the compressor.
- Moisture inclusion/ingress to the refrigerant line. This directly leads to compressor oil breakdown and eventual loss of capacity and compressor failure.
- Microleaks in the refrigeration circuit cause long-term loss of performance and compressor failure.
- A micro-leak of refrigerant can take years to manifest. It can appear as if the compressor failed when in actuality it is the loss of refrigerant in the circuit causing the performance degradation.
- A microleak with its concomitant loss of capacity, can cause the compressor to work harder and harder over time. This often leads to overheating failure of the compressor. The root cause, however, was the microleak of the refrigerant.
Aspen Systems assures that every system we design, and every system we manufacture, is properly charged and leak checked. We use robust quality control to assure that the issues outlined above will not occur with our products. During our assembly process, there are no fewer than 5 separate leak checks using helium, nitrogen, and vacuum testing. We will pull a system off the line for a microleak that cannot be detected by our customer for more than 6 years. The compressor oil is carefully determined for each system and added to each unit during assembly. Computerized refrigerant stations are programmed for each product we manufacture. At the end of the assembly line, we test each system for capacity and power draw. The units only get shipped if both of these parameters are within prespecified limits. All of the systems we manufacture are critically charged and hermetically sealed. There are no refrigerant leaks to occur through gaskets or seals.
For systems manufactured in this way, a full life expectancy if virtually guaranteed. The full range of capacity will be available to the end user for the expected 100,000-hour life. This is why we get so many compliments on our robust, reliable products from our customer base. We assure the quality is built in when our name and yours, go on it.
Next time we will cover the customization of vapor compression systems.
