Cost benefits of efficient electrical boosting power supply design

In recent years, Eurotherm by Schneider Electric has published several technical articles on the subject of next generation furnace boosting power supply systems, aimed at engineers and technical personnel. For financial decision makers, purchasing personnel and those responsible for energy saving, however, it was recognised that the design benefits needed a less technical explanation. With this in mind, Amber Watkin and René Meuleman have reworked what has been published so far, to explain the benefits in terms of cost savings and sustainability.

When choosing a boosting solution for a glass furnace, customers need to look ahead 15 to 20 years to get the best return on investment (ROI) in terms of capital expenditure (CAPEX) and operating expenditure (OPEX). Think about the changes that might be needed if business grows. Will it be necessary to increase throughput, what will the most efficient methods be and which new energy regulations might affect costs and carbon footprint? In other words, how will furnace electrical boosting affect business revenue?

To cope with potential issues, Eurotherm specifically designed its next generation boosting power supply solution with the future in mind, giving customers the flexibility to ‘buy what is needed now’, ‘expand later’ and ‘re-use elsewhere’.

REDUCED RISK OF UNPLANNED DOWNTIME

Glass furnaces need to run 24/7 for many years, otherwise the glass melt will start to cool. This slows down production and affects glass quality until the melt has returned to the correct temperature and consistency. In a traditional electrical boosting design, a single transformer and power controller are used to supply power to the heating electrodes. In the event of a device failure, the boost power is lost, causing the melt to cool and production to slow down. The repair is costly, with excessive downtime.

The Eurotherm design strategy utilises a network of multiple small transformers and power controllers. If one device fails, the others continue working, enabling the furnace to continue at full capacity. The remaining devices have enough bandwidth to supply the extra energy needed to make up for the loss. Multiple small transformers and power controllers often cost no more than using one large transformer, so there are no downsides to moving to this redundant design, which reduces the risk and cost of lost production due to unplanned downtime.

REDUCED CAPITAL SPEND + INCREASED PRODUCTIVITY

A furnace campaign needs to last 15-20 years but during that time, the demand for a successful glass product may rise. What if production needs to be increased by melting more glass in the same furnace footprint, or productivity levels need to be maintained as the output decreases towards the end of a campaign due to worn out components? In a traditional ‘fixed’ furnace boosting design, upgrading to gain extra power means replacing the whole system at a high cost, with excessive downtime.

Eurotherm’s design scheme is modular and easily scalable. Extra boosting power can be added to the furnace in steps during the campaign. Additional boosting can easily be added at any time, in order to melt glass faster during the furnace start-up sequence, run the furnace at a higher capacity, or extend the life of the furnace by a few years. It is the most cost-effective design if customers want to buy what is needed now and expand later.

STANDARDISED COMPONENTS

Global glass plants typically run on a variety of different voltages, so supply chain personnel need to specify and purchase different size transformers and power controllers for each region. Inventory costs are high due to multiple component sizes being kept for spares and expensive components cannot be reused by different regions at the end of a furnace campaign.

Eurotherm’s electrical boosting method uses a stepdown transformer, which transforms the incoming supply voltage down to the customer’s chosen plant voltage. This feature means all plants can run at the same intermediary voltage. The transformers and power controllers can all be the same size (standardised parts) for use in any global region, simplifying the ordering and reuse of parts and reducing inventory costs.

SUSTAINABLE FUTURE

Traditional boosting system design often uses components with mechanical parts that wear out over time. It is also common for damaging vibration to occur in the whole system, due to poorly applied power. Most system components are high value because they contain large amounts of copper and the resulting maintenance in replacement parts is costly, not only in financial terms but also in unnecessary environmental waste.

The components used in the Eurotherm design have minimal mechanical parts and are chosen or specifically designed for their high durability in the glass manufacturing environment. Also, the design in combination with Eurotherm’s expertly applied power control minimises vibration in the system. Less mechanical parts and less vibration reduce the risk of damage to expensive copper busbars and transformers. Unlike a traditional boosting system, most of the parts used in the Eurotherm design will last longer than the furnace lifetime and can be used in further furnace campaigns, making it more sustainable through extended life and reuse of these high value components.

FUTURE-PROOF SOLUTION

With over 50 years’ experience in the glass industry, Eurotherm has put a lot of effort into designing a futureproof boosting solution in terms of CAPEX and OPEX that is also efficient, reliable, sustainable and safe. Interested parties can also contact their global glass projects team, who are available to carry out energy surveys and calculate possible savings in the plant.