Picture this: you’re at the helm of a thriving company, and the decision falls on you. Do you go big with a centralized compressor system, or do you opt for the agility of a decentralized setup? It’s not just a technical choice—it’s a strategic move that could shape the future of your operations.
Factors to consider when navigating the maze of air demand
1. Pulse of production: air consumption patterns
Imagine your factory’s heartbeat, with its steady rhythm of base loads and the adrenaline rush of peak demands. It’s a dance of dynamics, where every surge in production or unexpected need must be met with precision.
2. Daily rhythms: running patterns
Like the ebb and flow of tides, your compressors’ running patterns tell a story—a tale of time and demand graphed out in peaks and valleys, guiding you to the right compressor size and layout.
- Running patterns (Hourly/Daily/Weekly): Based on the consumption patterns, a flow pattern can be observed, typically represented in a flow vs. time graph. This helps in deciding the size and distribution of compressors.
- Pressure vs. Volume pattern: These patterns should be analyzed on a volume vs. pressure graph. When air demand fluctuates, it triggers the switching on or off of compressors or running them in load or unload modes, depending on each compressor’s load and unload pressure settings. The below illustration explains how the overall pressure band increases in the installation of multiple compressors to a common header in a compressor room.
3. Application and criticality
- Diversity Factor: When there are multiple points of air usage, the total demand cannot be assumed as the sum of all individual consumptions. A diversity factor, based on process and experience, is applied to consider the base and peak load of air, preventing under-sizing or over-sizing of machines.
- Redundancy Requirement: For process plants, where applications are critical and cannot tolerate downtime, having redundant compressors is essential to support operations during scheduled maintenance or unexpected breakdowns.
- Project Investment: Large centralized compressor houses require significant investment compared to decentralized installations. Workplace compressors like GA+, VSD+, or VSD can avoid the need for a separate compressor house, reducing initial investment costs.
- Maintenance and Availability: The availability of compressors is paramount for Maintenance Managers as they are the lifeline of the company’s production output. Maintenance planning, annual budgets, and planned interventions influence the decision for a centralized or decentralized layout.
Centralized vs. Decentralized: pros and cons
A centralized compressor house can handle fluctuations in demand. However, installing multiple compressors to a common air header increases the overall pressure band, leading to higher energy consumption. For instance, operating at 1 bar above the required pressure equates to 7% of the full load energy of the compressor.
To address this, an ideal solution is to decentralize the compressor house, grouping compressors based on optimum pressure bands for different applications. This approach reduces energy consumption due to a decrease in the overall pressure band and avoids the need for large-diameter air pipes, minimizing leakage and investment costs.
In summary, the choice between centralized and decentralized systems depends on various factors, including application criticality, flow distribution, and specific requirements of the production process. To assist in making an informed decision, our engineers are eager to collaborate with you.