Considerations for sizing a temporary compressed air package

Choosing the right compressed air system is crucial for ensuring optimal performance and efficiency in various industrial applications. From pharmaceuticals and petrochemicals to automotive manufacturing and offshore wind, there is a critical need for a reliable and effective compressed air package. This blog looks at key considerations when specifying a compressed air solution.

Compressed air has its own International Organisation for Standardisation (ISO) standards, specifically ISO 8753-1. An oil-free environment is essential for many industries and applications, including pharmaceuticals, food and beverage production, and automotive manufacturing. However, for some applications, oil-flooded air compressors are acceptable, usually found in construction projects for tasks such as sandblasting. 

The air volume of a compressor is measured in cubic feet per minute (CFM) or liters per minute (L/min). It demonstrates the amount of air that the compressor can deliver at a given pressure. If this is wrongly determined it could lead to the following.

 

• Reduced efficiency and increased cost: under sizing the air volume required will lead to excess energy usage, as the compressors will have to run longer or more frequently, resulting in higher compressed air costs.
• Cost of running: a substantial proportion of the cost of running an air compressor comes from energy consumption, an ineffectively sized compressor will use more energy.
• Pressure fluctuations: lack of air volume can lead to fluctuations in air pressure, impacting the operation of sensitive equipment or causing system malfunctions.
• Downtime: disturbances in the system can disrupt process lines, leading to loss or delays in production.
• Increased maintenance: components of the air compressor may struggle with demand, leading to increased maintenance and repair costs.
• Equipment failures: systems that do not receive the correct air volume or pressure might fail or behave erratically, creating a safety risk for workers.

If the air flow is variable, it is important that the system can scale compressed air demand accordingly. An ‘air on demand’ compressed air system allows compressors to communicate with each other and automatically switch off or on as required, therefore saving energy.

• Incorrect pressure: incorrect pressure creates similar issues to not getting the volume right in a compressed air system.

• Loss of product quality: air pressure fluctuations can affect product quality, especially in industries where precise air pressure is needed for operations like automotive spraying, coatings, moulding, or packaging.
• Lower efficiency: plant and process equipment may rely on certain pressures to operate effectively; too little pressure will lead to reduced system efficiency.
• Safety concerns: high system pressure can lead to equipment malfunctions or cause components to fail unexpectedly, potentially injuring operators.
• Leaks: Incorrect pressure may exacerbate issues with leaks in the compressed air system, wasting energy and reducing overall system efficiency, leading to further pressure fluctuations.
• Vapor: fluctuating pressure can affect the vapor pressure and, therefore, the temperature at which saturation occurs.

This is the temperature at which water vapor condenses into liquid. Understanding the correct pressure dew point is essential to ensure your system does not reach it. 

A desiccant dryer directs air through desiccant material. As the air flows through the dryer, the desiccant absorbs moisture, resulting in dry air that is less likely to create problems in downstream equipment or processes caused by moisture or corrosion. All our dryers work at a -70°C dew point, so they can work in a broad range of sensitive applications.

Understanding noise requirements is essential. There may be noise regulations to meet within the workplace or if the compressor needs to be located near residential areas. Working in noisy environments can also pose a risk to employees.

Modern compressed air systems often have advanced components designed to limit noise. Our electric compressors have acoustic enclosures to mitigate noise, achieving noise levels as low as seventy-four decibels (dBA) at 1m, ensuring suitability for noise-sensitive areas.

Compressed air systems consume significant amounts of energy, making it critical to understand the power supply available to support them effectively. Key considerations include:

 

• Is the power supply sufficient? ensure that the power supply meets the demand of the compressed air system. Insufficient power can disrupt the system and its associated processes. Ensure it supports seasonal demands.
• Can the power available handle compressor start-up? fixed-speed compressors require a substantial power supply for startup. Consider investing in Variable Speed Drive (VSD) technology, which reduces startup power demands and increases efficiency. [Link to VSD Video]
• Does the power available account for seasonal variations? Verify that the power supply can accommodate changes in capacity requirements due to seasonal variations in demand.
• Is the power source dependable? ensure a reliable power source and implement control systems that can automatically restart compressors after a power outage. Customized control systems can enable your compressed air system to switch to standby generation and restart without manual intervention.
•  Is there a contingency plan for power interruptions? a contingency plan for power interruptions and ensure appropriately sized backup generators are on site. 

• Work with an experienced compressed air partner: an experienced partner should collaborate with you to understand the details of your requirements, as well as have knowledge of the sector and application. A partner should assist you throughout the project lifecycle from initial design to installation, commissioning, and continuous optimisation.
• Ensure equipment is fit for purpose: avoid using aging equipment.
• Conduct regular assessments and analysis: ensure maintenance schedules are adhered to, and safety inspections of compressed air systems, air compressors, and their components are checked frequently. Collaborating with a trusted partner enables them to take care of the maintenance for you.
• Use smart monitoring systems: Systems like Aggreko Remote Monitoring provide proactive diagnostics to detect changes in important system indicators that may create issues if left uninvestigated. Proactive diagnostics enable problems to be solved before they become significant. Energy consumption stats can also be monitored to optimise the package.
• Use control systems for multiple compressors: Control systems can scale air according to demand. When demand is low, only one compressor can run at a higher capacity while the others remain idle. A good control system will enable other compressors to start without manual intervention when required.