How Bristol Sites Can Reduce Compressor Energy Costs with VSD Retrofits

For industrial facilities across Bristol, compressed air is a fourth utility, as essential as electricity, gas, and water. It also represents a significant, often unmanaged, operational cost. As a Premier Distributor of Atlas Copco equipment, Control Gear has extensive experience retrofitting compressors across Bristol industries, demonstrating how this expense can be effectively managed and reduced. For businesses looking to enhance profitability and align with local sustainability goals, the solution often lies not in replacement but in a strategic upgrade.

In this article, we demonstrate how retrofitting an existing compressor with Variable Speed Drive (VSD) technology can deliver substantial energy savings, enhanced operational stability, and a clear return on investment.

The Inefficiency of Fixed-Speed Compressors

A fixed-speed compressor is simply on or off. When on, the motor runs at its maximum speed, consuming full power, even when the air demand is low or nonexistent. To “wait” for the next production cycle, when the demand will kick in again, the compressor will enter an “unloaded” state. 

At this point, the motor is still running, but instead of producing air, it consumes between 30% and 70% of the power at full load without actually contributing to the production. Any Bristol-based facility with an uneven production profile, from aeronautical engineering in Filton to a food production plant, is losing money by generating this unnecessary heat and topping up their electricity bills unnecessarily.

The Smart Solution: Variable Speed Drive (VSD) Technology

A VSD retrofit transforms an inefficient, fixed-speed machine into an intelligent, demand-responsive asset. The technology works like the accelerator in a car, precisely adjusting the motor’s speed to match the real-time air demand of your facility.

Control Gear specialises in retrofitting market-leading VSD technology, including:

• Atlas Copco GA VSD+ Series: These oil-injected rotary screw compressors offer up to 50% energy savings.
• Atlas Copco Z VSD+ Series: For sensitive industries like food & beverage or electronics, these oil-free units provide Class 0 certified clean air.

These retrofits integrate with advanced controllers like the Elektronikon® Touch and SMARTLINK, which provide remote data and predictive maintenance alerts to ensure sustained peak efficiency.

The Benefits of a VSD Retrofit

While the primary driver for a VSD retrofit is a reduction in energy costs, the operational advantages are equally compelling.

Substantial Energy Savings & Rapid ROI

By eliminating wasteful off-load running, a VSD retrofit can cut a compressor’s energy consumption by 35-50%, with the latest Atlas Copco VSDˢ technology achieving savings of up to 60%. This directly supports Bristol’s 2030 carbon-neutral goal and can be supported by local incentives like the WECA Green Business Grant, which offers up to £15,000 to fund qualifying projects.

Sample ROI Calculation for a Bristol Manufacturing Site:

• Compressor: 75 kW Fixed-Speed Screw Compressor
• Operation: 6,000 hours per year (two shifts)
• Baseline Annual Energy Cost: £63,360
• Projected Post-Retrofit Energy Cost: £42,240
• Gross Annual Energy Saving: £21,120
• Typical Project Cost: £45,000
• Simple Payback Period: 2.1 Years

Enhanced Operational Stability

VSD compressors maintain system pressure within a very narrow range (usually ±1.5 PSIG). This precision eliminates the fluctuations that can affect the quality of precision tooling, pneumatic conveying, and automated equipment. It also allows the entire system to run at a lower average pressure, which can lead to additional savings.

Reduced Mechanical Wear and Tear

A VSD’s “soft start” feature slowly accelerates the motor to full speed. This eliminates the massive inrush of current that can cause mechanical shock and electrical stress, lengthening the life of bearings, couplings, and the motor.

Heat Recovery Integration

Up to 94% of the electrical energy used by a compressor is converted into heat. An integrated energy recovery system can capture this waste heat and repurpose it to heat water or facilities. In some applications, this can offset hundreds of tonnes of CO₂ annually, further reducing your utility bills and maximising the return on your investment.

Is Your Bristol Business a Prime Candidate for a VSD Retrofit?

A VSD retrofit delivers the most significant benefit to facilities with variable air demand. Your business is likely an excellent candidate if you answer “yes” to any of the following:

• Do you operate multiple shifts with different production levels?
• Does your air demand vary between weekdays and weekends or seasonally?
• Do your processes, like those in aerospace manufacturing, involve intermittent or cyclical air needs?
• Do you operate a logistics facility in a location like Avonmouth, where pneumatic systems have fluctuating loads?
• Does your food & beverage plant have distinct production runs followed by lower-demand cleaning cycles?

The Path to a Successful Retrofit Starts with Data

Embarking on a retrofit without a complete understanding of your system is a gamble. The essential first step is a professional Compressed Air Audit. Using advanced diagnostics like AIRScan, our engineers install data loggers to map your exact air demand profile. A typical installation takes just 1-2 days with minimal disruption to your operations.

This data-driven process:

• Precisely quantifies your current energy consumption and waste.
• Identifies costly air leaks that can be fixed beforehand.
• Provides the empirical basis for accurately sizing the VSD and projecting your ROI.
• Ensures the final solution aligns with UK standards like BS ISO 11011 and supports your compliance with schemes like ESOS and SECR.

Why Choose Control Gear for Your Bristol Retrofit?

With over 50 years’ experience working with industrial businesses in Bristol, South Wales, and the West, Control Gear knows how to take a technically led approach and deliver quantifiable outcomes.

• Local Authority: As leading suppliers in Bristol, we understand the pressure and demands placed on key industries in the area.
• Atlas Copco Premier Distributor: We supply and install Atlas Copco VSD technology.
• Brand-Agnostic Expertise: Our engineers have in-depth experience retrofitting all leading brands (Ingersoll Rand, CompAir, HPC Kaeser), so we can be confident that the solution is right for your equipment.
• Certified & Compliant: All our engineers are certified to ISO 9001, 14001, and 45001, as well as FGAS, ensuring you’re in safe hands for a professional and compliant installation.
• Long-Term Support: We offer service contracts, such as the Guardian Service Plan, to protect your investment and provide you with long-term peace of mind.

Begin with data. Book a no-obligation compressed air audit and receive a bespoke roadmap to demonstrate how much your Bristol site could save.