Motor Systems - Glass Industry

In glass manufacturing plants motors are used throughout in compressed air systems, cooling water pumps, furnace air blowers, ventilation fans, as well as for transport conveyors. With systemic approaches and strategic decisions, energy consumption of the motor system can be significantly reduced.

A systems approach is essential when aiming to improve energy efficiency of a motor system in a facility. Such an approach takes the entire motor system – including motors, drives, driven equipment such as pumps, fans, and compressors, and controls, distribution system, and even end-users – into consideration, rather than focusing on motors only. Paying attention to both energy supply and energy demand sides, such an approach not only aims to optimize energy use, but also strives to improve system uptime and productivity.

A systems approach typically involves the following steps:

  1. All applications of motors in a facility should be located and identified;
  2. The conditions and specifications of each motor should be documented to provide a current systems inventory;
  3. The needs and the actual use of the motor systems should be assessed to determine whether or not motors are properly sized and also how well each motor meets the needs of its driven equipment.;
  4. Information on potential repairs and upgrades to the motor systems should be collected, including the economic costs and benefits of implementing repairs and upgrades to enable the energy efficiency improvement decision-making process;
  5. If upgrades are pursued, the performance of the upgraded motor systems should be monitored to determine the actual costs savings. 

Selecting efficiency motors, proper motor sizing, effectively matching motor speeds to loads, and upgrading system components are among the key approaches that help improve energy efficiency of motor systems (Worrell, et al., 2008. p. 38)

Motor Systems - Glass IndustryTechnologies & Measures

Technology or MeasureEnergy Savings PotentialCO2 Emission Reduction Potential Based on LiteratureCostsDevelopment Status
Power Factor CorrectionCommercial
Motor Maintenance

The savings associated with an ongoing motor maintenance program could range from 2% to 30% of total motor system energy use (Worrell et al., 2008. p. 40)

Commercial
Proper Motor SizingCommercial
Adjustable Speed Drives

Typical energy savings with the use of ASDs are shown to vary between 7% and 60% (Worrell et al., 2008. p.41).

 An audit in a US based container glass industry identified energy saving potentials by installing ASDs for cooling water pumps, for furnace air and stack draft blowers, and for cooling blowers in the forming and glass handling sections. Savings for the cooling motor pumps and for the furnace air blowers are identified to be 524,600 kWh/year and 808,400 kWh/year, respectively (Worrell et al., 2008. p. 41).

 Replacing old cooling water pumps with new ones fitted with ASDs an automative glass company in the US saved 3.2 GWh/year of energy, while also reducing the need for water use and the use chemicals for water treatment (Worrell et al., 2008. p. 41). 

 In a speciality glass factory in the US, energy saving potentials of 700 MWh/year, 200 MWh/year, and 100 MWh/year are identified by installing ASDs for mold cooling fan motor, for a cooling loop motor, and for a machine cooling loop, respectively. 

 By installing ASDs on the main suction fan motors in its wool forming process, a glass wool insulation producer in the UK was able to reduce the energy consumption of the fans by 55%, saving 3.8 GWh of electricity annually (Worrell et al., 2008. p. 41).

 By installing ASDs on the main suction fan motors in its wool forming process, a glass wool insulation producer in the UK was able to reduce CO2 emissions by 1600 tons/year (Worrell et al., 2008. p. 41).

 In a US based container glass indsutry, the estimated payback times for installing ASDs were as following: 1.8 years for the cooling water pumps; 1.7 years for the furnace air and stack draft blowers; 1.8 years for the cooling blowers in the forming and glass handling.

 Savings in the automative glass manufacturing plant totalled $ 280 000 (energy savings alone $ 98 000). The investment costs were $350 000, giving a payback period of 15 months (Worrell et al., 2008. p. 41). 

 In the speciality glass factory, payback times for installing ASDs for mold cooling fan motor, for a cooling loop motor, and for a machine cooling loop had payback times of 1 year, 1.2 years, and 2.8 years, respectively (Worrell et al., 2008. p. 41). 

 The payback period for installing ASDs on the main suction fan motors for the glass wool insulation material production, the plant in the UK realized a payback time of 2 years (Worrell et al., 2008. p. 41).

Commercial
Strategic Motor Selection Using Life Cycle Costing

In general premium efficiency motors are most economically attractive when replacing motors with annual operation exceeding 2,000 hours/year.

US flag An audit of two Glass Container plants in the US found opportunities to replace large motors with energy-efficient motors with a payback period of 2.5 years or less (Worrell et al., 2008. p.39).

Commercial
Minimizing Voltage Unbalances.

For a 100 hp motor operating 8,000 hours per year, a correction of the voltage unbalance from 2.5% to 1% will result in electricity savings of 9,500 kWh or almost $500 at an electricity rate of $0.05/kWh (Worrell et al., 2008. p.42)

The typical payback period for voltage controller installation on lightly loaded motors in the United States is 2.6 years (Worrell et al., 2008. p.42).

Commercial
Motor Management PlansCommercial
Use of High-Efficiency Cog Belts

As compared to standard V-belts cog belts and high-torque cog belts are 2% and 6% more energy efficiency, respectively. Motor load reductions of 2 to 10% have been shown from replacing vee belts with cog belt (Worrell et al., 2008. p.42). In the US, installation of efficient notched belts on belt-driven applications at in a glass plant was estimated to save 200 MWh/year (Worrell et al., 2008. p.42).

estimates the payback for replacing standard belts with more efficient ones to be 6 months to 3 years. Other case studies taken from each of the glass segments (fiber, flat, container, and specialty) estimate the average payback period over all glass sectors for installing more efficient belts at less than 10 months. The payback time was virtually immediate for installing efficient notched belts on belt-driven applications at in a glass plant in the US (Worrell et al., 2008. p.42).

Commercial

Motor Systems - Glass Industry Publications

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37-42