Where exactly ISX saves energy: a station-by-station breakdown of savings

Rising operating costs are prompting glass manufacturers to compare three options: continuing with existing equipment, retrofitting it or investing in a new individual section (IS) machine. Connected load alone is not enough to make that decision. IS machine energy savings also depend on output, compressed air consumption, process stability, reject rates and downtime.

Why energy savings start with operating data

Measure IS machine consumption within a clearly defined production boundary. At the hot end, the process under review starts with glass gob feeding, continues through forming and ends with bottles or jars being arranged before the annealing lehr. Different measurement boundaries before and after a change prevent a like-for-like comparison.

Total consumption per shift does not tell the whole story. A machine with a higher hourly output may use more energy per hour but less per tonne. The same principle applies to consumption per 1,000 packed containers. The assessment must also cover reject rates, cooling and unplanned interventions.

The full-servo ISX machine is designed to deliver energy savings of up to 50% compared with conventional IS technology. This design target was reported in Glass Worldwide in 2019. It is not a guaranteed outcome for every installation. The actual benefit depends on the baseline machine, forming process, product mix, capacity and measurement method.

A technical director therefore needs more than a catalogue power rating. They need electricity consumption in kWh and compressed air consumption in Nm³ during stable production of a specific container. Only when these figures are expressed per saleable container can they show whether IS machine energy savings reduce actual operating costs. For Nm³ measurements, specify the reference temperature and pressure so that air volumes remain comparable.

Which parts of an IS line have the greatest effect on consumption?

Once the measurement boundary is established, break the line down into individual energy users. Mechanism drives, mould cooling, compressed air, gob feeding and cycle timing all affect the energy balance. Pneumatic systems also use compressed air to drive mechanical movements. Electric servo drives carry out those movements using controlled, repeatable motion profiles.

The gob feeder is a separate part of the line. The ISX servo feeder electronically synchronises the plunger, tube rotation, tube height and shear mechanism. Repeatable motion helps maintain gob weight, shape and timing as the glass enters the delivery system.

Gob variation can alter glass distribution in the container wall. Operators may then need to adjust settings more frequently, and the line may produce more rejects. Energy used to make containers that never reach packing increases unit costs. Track the pack-to-melt ratio as well: the proportion of melted glass that becomes packed, saleable product.

Blow and Blow (BB), Press and Blow (PB) and Narrow Neck Press and Blow (NNPB) have different process characteristics. They differ in the containers produced, glass weight and forming cycle. Comparisons must use the same process, container specification, number of active sections and target output.

• Mechanism drives: measure electrical energy during steady production, start-up and product changeovers.
• Compressed air: record volume in Nm³ and separate process air from other uses.
• Mould cooling: assess consumption alongside cycle speed, temperatures and container quality.
• Reject rates: quantify the energy consumed in producing containers that do not reach packing.

An audit structured this way identifies whether the main losses arise in the drives, gob feeding, air distribution or an unstable process. It also shows which improvements can be verified separately after implementation.

How ISX changes the production energy balance

ISX 24-01 uses fully electric servo drives and a control system with a CPU 1518TF processor. An Industrial PC manages the recipes. Operators can save adjustable forming-cycle movements and reload them when returning to the same job.

Stored recipes reduce the need to establish baseline settings repeatedly. After a product changeover, they can therefore shorten the time needed to achieve stable operating conditions. Verify this benefit through changeover time, start-up duration, reject rates and energy consumption during start-up. Without these figures, the benefit cannot be quantified accurately.

The control environment includes TIA Portal, a Siemens IPC 477E human–machine interface (HMI) with a 15-inch screen, and a SCALANCE XC208 network switch. The system uses standard Siemens components. The design references IEC standards, CE marking requirements and UL standards. These details support supplier qualification, document management and spare parts standardisation.

ISX is designed to achieve energy savings of up to 50% compared with conventional IS technology. The design also targets lower compressed air consumption and increased cooling capacity. Additional cooling capacity can support forming stability, but its effect depends on the mould, container, recipe and required cycle time.

IS machine energy savings therefore result from several changes working together. These include direct electricity consumption, compressed air demand, start-up duration, the number of adjustments and reject rates. Include usable production capacity in the assessment too. The presence of servo drives alone does not demonstrate a particular operating result.

The ISX machine specification can be supplemented by an assessment of the particular line through the development and automation services of T&T, Turnov s.r.o. The assessment must be based on operating data and a clearly defined line constraint.

How to translate savings into operating costs

Once consumption has been broken down technically, calculate its financial impact. Total cost of ownership (TCO) includes capital expenditure, electricity, compressed air, cooling, maintenance and spare parts. Add reject costs and downtime costs. Assess every option over the same period and within the same system boundary.

Build the baseline model from the existing line’s data. Choose a representative container and a period without an exceptional breakdown. Record the forming process, container weight, number of active sections, line speed and output in tonnes per day (tpd). Include the number of packed containers.

1. Define the reference job: specify the bottle or jar, the BB, PB or NNPB process, and the target output.
2. Measure energy inputs: record kWh and Nm³ of compressed air over the same period.
3. Add production results: report tpd, packed containers, rejects and hours of downtime.
4. Normalise consumption: calculate kWh/t, kWh per 1,000 containers and Nm³ per 1,000 containers.
5. Cost the operating effects: use your contracted energy rates and site-specific costs for compressed air, maintenance and downtime, expressed in the local currency.

• Electricity consumption per 1,000 containers: divide measured kWh by the number of packed containers and multiply by 1,000.
• Air consumption per 1,000 containers: apply the same calculation to measured Nm³.
• Consumption per tonne: divide the energy input by the mass of packed production in tonnes.
• Annual financial impact: multiply the difference in unit consumption by the planned production volume and the relevant unit price, such as cost per kWh or per Nm³. Avoid counting compressor electricity twice if it is already included in the compressed air cost.

Do not calculate savings simply by subtracting rated power figures. A nameplate rating does not describe the load during the cycle, start-up demand or compressor house consumption. Nor does it account for differences in output. For the carbon impact, use emission factors appropriate to the electricity reporting method and fuel used. For national reporting, the relevant year’s official national greenhouse gas conversion factors provide a standard reference.

Compare three scenarios for the investment decision. Retaining the existing equipment requires estimates for repairs, consumption and downtime. A retrofit addresses a selected bottleneck, such as gob feeding or condition monitoring. A new machine affects more cost categories but requires capital investment and a planned installation shutdown.

T&T, Turnov s.r.o. offers a feasibility study within 48 hours. The technical assessment draws on the description of the constraint, operating data and project documentation. Its output describes the proposed solution and the conditions under which the expected benefit can be verified by measurement.

How to verify results through accurate on-site measurement

Prepare the measurement plan before changing the equipment. Define the measurement points, logging interval, system boundary and person responsible. After commissioning, repeat the measurements with a comparable container, process and load. Use the same method to normalise the results.

Separate the IS machine’s consumption from that of the feeder, compressors, conveyors and annealing lehr. Alongside individual loads, monitor the whole defined section of the line. Component-level data explains the cause of a change; combined data shows the effect within the measured boundary and its contribution to overall plant consumption.

Equipment	Parameter assessed	Documented design specification
ISX 24-01	Production capacity	30–220 tpd
AL 25-03	Insulation thickness	300 mm
AL 25-03	Heating zones	Max. 600 °C
AL 25-03	Cooling zones	Max. 450 °C
AL 25-03	Exit temperature	Max. 200 °C

The table gives design specifications, not measured IS machine energy savings. ISX capacity within the 30–220 tpd range is confirmed for each project. The AL 25-03 lehr specifications define the available temperature envelope. Operators set the actual profile according to the container and the required cooling schedule.

Always report measurement results alongside the operating conditions. State the container, process, output, measurement boundary, monitoring period and line condition. Also record the number of active sections and the proportion of production successfully packed. This makes the assessment repeatable and suitable for internal capital expenditure approval.

How to link energy use with cooling and quality

The next step is to link energy data with container quality. Unstable mould cooling can limit cycle speed or increase the number of adjustments needed. ISX’s increased cooling capacity offers greater scope for process setting. Its benefit must, however, be confirmed by output, consumption and reject data.

Downstream of the forming machine, the servo stacker (lehr loader) controls the flow of containers into the annealing lehr. It arranges hot bottles in rows and also supports staggered stacking. Consistent spacing helps containers enter the lehr’s temperature zones in a predictable pattern.

Uneven cooling can leave internal stress in the glass and increase the risk of breakage. The cost is not limited to scrapping the finished container. It includes the energy consumed in feeding, forming, handling and annealing. Include this effect when calculating energy consumption per unit of packed production.

The TT Connect monitoring system collects sensor data via TCP/IP. It supports remote equipment condition monitoring and predictive maintenance. Historical data can help link rising consumption to changes in operating condition, maintenance activity or deviations in a particular recipe.

How to prepare a line upgrade decision

Before requesting a quotation, document the existing machine configuration, the BB, PB or NNPB processes used, the product range and capacity. Describe the main line constraint. Include electricity and compressed air consumption, reject rates and product changeover times, together with records of planned and unplanned downtime.

• Technical director: compares TCO, investment scenarios and the effect on energy consumption and carbon emissions.
• Hot-end manager: assesses gob stability, recipes, mould cooling and product changeovers.
• Maintenance manager: checks service access, spare parts, condition monitoring and shutdown requirements.
• Group procurement: checks applicable IEC standards, conformity documentation and CE marking or other conformity marking required in the destination market, any specified UL requirements, Siemens components and EPLAN documentation.

Structure the enquiry around the identified bottleneck. Options may include a new ISX machine, a standalone servo feeder, an annealing lehr, a servo stacker or additional condition monitoring. Each option needs its own scope of supply, measurement plan and operating cost calculation.

For an initial assessment, use the technical assessment contact or the form on the T&T, Turnov s.r.o. development page. Have the process, container specification, tpd, kWh, Nm³, reject rate and description of the constraint ready. The feasibility study offered within 48 hours assesses technical suitability and provides a basis for the TCO calculation. IS machine energy savings can then be evaluated against the specific line and verifiable operating data.