Understanding best practices for compressor storage for a lubricated trim compressor with load/unload controls is critical for optimized performance.
- Prevents frequent cycling of the compressor which reduces maintenance costs and saves energy
- Collects condensate, which may pass downstream from the compressor discharge
- Provides radiant cooling of the compressed air to reduce moisture content (oil aerosols and water) and assist the operation of the dryer
- Reduces pulsations in pressure from the discharge of a reciprocating compressor
- Helps to stabilize fluctuations in system pressure
- Stores compressed air as potential energy to supply sufficient air for large surge demands.
A dry receiver is useful for storing clean and dry air. It can be located directly downstream of the air treatment equipment or anywhere in the facility to supply air for specific surge loads. Many dust collectors have dry receivers incorporated into their design to assist in partially satisfying their demand event.
The higher the cycle frequency, the less efficient the compressor runs at reduced loads, especially if it is a lubricated compressor. The changes to the power versus flow characteristics with changing storage receiver sizes are shown in Figure 1. In addition, a lubricated, load/unload compressor can be more energy efficient than a VSD compressor when adequate storage is installed (Figure 2). The equation to size a receiver for a demand event of known duration is shown in Figure 3.