40 Energy & Water Processes & Drives Opportunities

REVIEW

The first step to take to improve understanding of performance and target savings straight away

REDUCE

Target improvement measures that directly decrease energy consumption first

1. Last person off switch

• This involves a simple switch on a circuit that includes all the relevant process equipment, with the switch often positioned near the exit door to an area.
• This can be a simple way to ensure all equipment is switched off at the end of the day (or shift).
• The risk is that this also becomes a ‘First person in’ switch. Be careful about including equipment that doesn’t need to come up with the first person in – see fire-up schedule idea below.
• Check all production plant for complete shutdown when switched off.

2. Use fire-up schedules to manage the start-up/switch-off of significant consumers

• A fire-up schedule is an idea we’ve often introduced to processes such as restaurant kitchens, which schedules out all the significant services and consumers, within an area, and their agreed operating times.
• This type of schedule can be used to facilitate discussions with colleagues to target when equipment is running unnecessarily. It can also help to trial ideas to reduce running hours in a managed way. 
• For example, look at ways to delay starting equipment up for as long as is possible at the beginning of the day or shift. Take into account any time required to reach operating conditions e.g. for heating ovens or compressor systems.
• Where a service is required 24/7, and there is multiple provision, consider itemizing out each consumer and reducing service levels during periods of low demand e.g., shutting off some operating theatres overnight when otherwise they would all be left on.
• Use the fire-up schedule to routinely and continuously challenge operation times of equipment in a managed way.

3. Use local timers to switch off independent equipment ($)

• Simple local timers are still often the easiest way to locally control local equipment and motors – as long as someone is responsible for checking and optimizing the time settings.
• This is used, for example, to avoid machines being left on for long periods without being used, e.g. for vending and food dispensing refrigeration equipment which otherwise would be left on all the time.
• Also consider use of local times where intermittent operation of equipment still produces the same results if operation was continuous e.g. for some mixing, blending or water pumping processes.
• Be careful about having too many timers that need checking and optimizing. The risk here is that they are all switched on permanently as they are too many of them to effectively manage.
• Use an operating schedule to discuss and optimize equipment timings with colleagues who best understand the operating needs of the system. Routinely challenge operating times to reduce consumption further.

4. Turn down system flow-rates

• Identify opportunities to reduce flow-rates at full load for air ventilation or pumped water systems e.g., using variable speed drives on system fan or pumps motors.
• Minimize any unnecessary overall system pressure losses - target any combined throttling control in the system provided by say fixed dampers, valves or other fixed pressure drops.
• Under part-load conditions, use variable flow controls for more efficient part-load operation – typically, only 20% of full load energy consumption is required for half load flow volume.
• Consider isolating the centralized load of any local equipment and machines while being unused; for example, unused machines can be isolated from a central extract system by fitting local dampers on a variable air volume (VAV) centralized system.

5. Turn down temperature or pressure control set-points

• Operating control set-points for many systems are usually determined at design stage based on assumptions; because we are generally risk averse, set-points are usually set on the high side.
• For process heating systems, look to reduce flow water temperatures or system steam pressures to reduce overall system energy losses.
• For cooling processes, set the highest system cooling temperatures possible.
• Reduce control static pressure set points in variable air volume distribution systems as much as possible; look to reduce it to the point where all terminal unit controls are as open as possible at full load.
• The pressure set-points for air compressors, for example, are usually set at around 7 bar (100 psi). Reducing a compressor operating pressure from 7 bar to 6 bar can reduce power consumption by 2-4%.
• Continually challenge temperature and pressure set-points based on actual requirements to achieve energy savings.

6. Enhance insulation levels ($)

• Enhancing insulation levels can reduce heat energy losses for hot water heating systems, industrial heaters and fryers, etc., and reduce cooling energy losses from chilled water systems.
• Enhancing insulation can also improve system control at temperatures in use.
• Look for opportunities to increase insulation levels (e.g. for cold room storage areas) and draught proof against any possible air leakage around doors e.g. look to fit curtains to tunnel-oven entrances.
• If you can, we usually recommend increasing insulation levels to as much as can be easily fixed within organizational criteria for return on investment.

7. Appoint a local performance improvement champion

• We find the biggest opportunities to reduce consumption often come about by connecting up different people with different perspectives.
• A local performance improvement champion acting as a key connector can coordinate local discussions and activities to help optimize overall process performance including its energy and water performance.
• Many centralized compressor systems are often left running for the whole working day; keeping them running on stand-by, even if at minimum levels, can still consume 20-70% of their full load power.
• Set hot water temperatures to lowest permissible agreed settings.

8. Use decentralized systems ($)

• In the right circumstances, decentralization can be an energy effective strategy to reduce distribution system losses for process systems.
• Look at opportunities to separate out different types of loads to avoid having central systems running longer than otherwise would be necessary. 
• In some application, e.g. dentistry, local micro-motors can be used in place of compressed air.
• Review hot water requirements and consider replacing centralized hot water generation with local direct (or instantaneous) generation to minimize storage and distribution losses.

REUSE

Once loads have been reduced, then prioritize routine and maintenance improvement practices (that don’t require significant investment)

1. Raise awareness and train colleagues

• Empower colleagues - discuss and agree standard operating principles and management policies for process systems. Develop practices to minimize energy losses. For example, locate chilled food for longer-term storage at the back of chilled storage containers.
• Raise awareness so local users understand the impacts of their activities. Involve local champions in checking and challenging the area’s basic control settings: ensure timeclocks are reset after clock changes, automatic controls are not unintentionally left in manual mode (in ‘hand’), and that settings are not set-back to overtly safe levels.
• Ensure switches and local controllers are clearly labelled and accessible.
• For multiple equipment installations, look to switch units on/off to match demand.
• Switching off equipment during breaks, or when operators are away from the process, can save up to two thirds of normal energy consumption.
• Check that system operators, service partners and contractors are all adequately trained, and can carry out process performance reviews and proactive maintenance activities as required; they should be competent, have the relevant qualifications and have received adequate safety training to deal with any risks.

2. Make sure to enable energy savings features

• Many systems and processes come with pre-programmed energy savings features; however, we find that may are never enabled or switched off.
• Raise awareness of the energy efficiency potential and intent of system and equipment designs. Discuss the opportunities with suppliers and other specialists.
• Look to activate and continually review automatic standby levels and switch off modes whenever possible.

3. Carry out regular maintenance

• For all significant process consumers, check latest supplier requirements for system maintenance. Without a maintenance routine in place plant, equipment, pumps, fans, etc., utilities consumption can significantly increase. Maintenance also extends plant life and reduces the likelihood of breakdowns.
• Motors require regular cleaning and lubrication to bearings and associated drives; also check cooling fans and vents.
• Regularly clean fan blades, pump impellers, etc. Keep filters and distribution systems clean to minimize pressure drops.
• Include checking of compressors, evaporators and condensers; check all refrigeration systems for level of charge.

4. Optimize efficiency of transmission systems e.g. motor drives

• Involve suppliers and service partners in the optimization process.
• For motor drives, look to reduce losses as much as possible: check for belt tension, pulley alignment and lubrication. Consider replacing V-belts with modern flat low friction belts.
• For electrical transmission systems, look at opportunities to reduce voltages at transformers. Many systems run at higher voltages than required which can lead to additional energy losses.

5. Routinely carry out inspections for leaks

• Look for and eliminate leaks within process systems.
• Water system leaks can be highlighted by monitoring for consumption with all water consuming equipment switched off. Underground leaks can sometimes be highlighted using thermography.
• Leaks in compressor systems can also go unnoticed for a long time and be expensive. In compressed air systems, losses can be as much as 40 to 50% of the generated output. Try to listen and see if there are any audible air leaks within the system. Also, check for safety valve leaks and whether any manual drain valves have been left marginally open. Be careful about using metal clips on airlines, as these can cause leaks.
• For ventilation systems, minimize duct and damper air leakage which can also impact on performance and controllability.

6. Use variable speed drives (VSD) on motors ($)

• A variable speed drive (VSD) is a type of motor controller that can vary the speed of an electric motor by varying the frequency and voltage supplied to the motor.
• Used in an energy effective way, reducing the speed of a pump or fan by 20% can halve its running cost.
• Other names for VSDs are variable frequency drives, adjustable speed drives, adjustable frequency drives, AC drives, micro-drives and inverters.
• For some applications, using multi-speed motors can also provide energy effective control for part load operation.
• Many VSDs aren’t being used as effectively as they could be. Set up and continually optimize and improve the control settings to make the most out of the VSD investment.

7. Retrofit equipment controls

• Involve suppliers and system specialists to discuss opportunities to retrofit additional equipment controls to reduce consumption and enhance performance.
• Look at energy efficiency controls; e.g. consider use of ‘start on demand’ controls for escalators and travellators. Consider soft-start motor controllers on freezers, refrigerators, and chilled display cabinets.
• Look at water efficiency controls e.g. use of control systems for water system urinals, push or knee operated controls for taps, etc.
• For electrical distributions systems, power factor correction can help to reduce the reactive power fed back into the local electricity grid – thus reducing any additional costs you may be charged for by the local utility company for excess power factors.

8. De-rate plant provision if oversized (and practical to do)

• Target oversized processes and plant that have poor efficiencies:
• Pumps may be de-rated by changing to a smaller impeller, by trimming the impeller, or by adjusting the pulley size.
• Consider reconfiguring significantly oversized three phase motors from delta to star wiring.
• Reduce hot water storage and generation by using smaller units with quicker recovery times.
• Partition off any areas unused in cold storage containers (and switch off or de-rate associated evaporators).

RECYCLE

Talk to colleagues, share experiences and try out proven approaches and technologies used by others

1. Survey process users, operators and service partners

• Gain feedback from operators and users on current performance of local processes and ask for their ideas for improvement opportunities.
• Talk to suppliers and industry specialists to obtain informed opinions about comparative levels of process system performance, including energy/water performance, and ideas they have to improve overall performance.

    2. Use monitoring and targeting (M&T) techniques ($)

• Too often, unexpected energy and water waste goes unseen in process systems.
• Automated consumption monitoring of production processes and demand can help support the identification of avoidable energy/water waste. Half-hourly consumption data is typically used to do this.
• Particularly target excessive demand used out of normal operating periods.
• Consider use of load shedding to reduce maximum demand at peak times – this could be facilitated using local control systems or full building energy management systems.

3. Improve procurement policies

• Ensure equipment and motors are of the correct size for the application, once opportunities to reduce load have been considered.
• Once appropriate size has been determined, look to make use of efficiency rating labels to help establish energy and water effective procurement policies.
• For example, fitting High Efficiency (IE2) or Premium Efficiency (IE3) motors can reduce motor energy consumption by up to 5% for the same power output demand compared to standard new motors; this investment typically payback within 1-3 years. 
• Think again about policies to repair/rewind motors as this practice reduces motor efficiencies. Only rewind motors when absolutely necessarily. 
• When replacing equipment, look to recycle old machinery and equipment as possible.
• Discuss industry standards and opportunities with specialists.

4. Recover kinetic energy ($$)

• Kinetic energy is the energy of mass in motion. We can sometimes capture this energy before it is lost. 
• Traditionally, this has been expensive to do, but certain applications are becoming more cost effective, or help to raise awareness of avoidable waste issues to capture hearts and minds.
• Regenerative braking, for example, can be used to recapture some of the energy that would normally be lost by braking systems. Cycling generators and kinetic pavements (harnessing the power of footstep) can also be used to generate electricity.
• To minimize distribution losses, look to recycle this energy for nearby power loads or charging points, particularly if you can keep it as a 12volt supply.

5. Recycle waste heat ($)

• Look for opportunities to recycle waste heat from process systems. For example, waste heat from coil coolers, or air-cooled compressors may be used to pre-heat water for other purposes, such as for domestic hot water.
• Using a thermal camera (thermography) can help to identify equipment that gives off high levels of waste heart.
• When considering application, first look for opportunities to recycle the heat within the same process, e.g. using hot-gas recirculation to reduce temperature stratification and promote better heat transfer. 
• Then consider whether heat can effectively be recovered from the process.

6. Recycle water/effluent discharge ($)

• Look for opportunities to recycle wastewater from water systems. The potential will depend on the levels of cleaning required.
• If possible, recirculate water for other purposes, without requiring significant remedial measures. For example, either directly (e.g. using greywater for gardens), or indirectly (e.g., using water for industrial cooling applications).
• There may be opportunities to recover collected rainwater, or process water such as from sinks, to be used within applications such as toilets.

7. Learn from continually optimizing equipment settings and controls

• Look to continually learn by iteratively challenging control settings and looking to stretch performance in use.
• Work with specialists to review and fine-tune control schedules, differentials, loops, etc., to minimize losses at low loads.
• If experience shows that the level of control at low loads is insufficient, consider replacing control valves or terminal units with correctly sized components.
• In particular, pay attention to optimizing plant sequence and load controls, operating pressures and free cooling and heating cycles.

8. Use KAIZEN case studies - share your experience with colleagues

• KAIZEN is the Japanese word for “change for the better”. This Asian philosophy is based on continual improvement that can be applied to any process in a way that involves everyone.
• Look to use standard kaizen case-study templates to capture experiences and actions and share them with colleagues.

RETHINK

Challenge your mindsets, look for new ways of doing business, trial new ideas and invest in more energy effective and sustainable solutions; review business cases and their ROI

1. Innovate approaches & processes ($$)

• Review all systems in terms of energy and water performance, and understand the value they add (or don’t add) to the overall process.
• Brainstorm alternative approaches to meet process requirements. For example, pay attention to alternative heat treatment processes, furnaces, washers, dryers, etc.
• Design out utility requirements if possible, e.g. using waterless urinals.
• Look for opportunities to relocate services to benefit from economies of scale e.g. a restaurant supplier centralized some of the cooking of meals within larger kitchens to distribute to their simplified local restaurant outlets.

2. Replace oversized equipment ($$)

• Using oversized equipment (compared to the required demand at peak load) can significantly increase their energy and resources consumption.
• Target significant consuming process assets and equipment, and review how they perform at peak load, low load and part-load scenarios. Consider whether they are under energy effective control at the different levels of load.
• Rethink whether any changes in size, or other remedial measures would improve the performance of any oversized or undersized assets.
• For example, correctly sized motors ensure good levels of energy efficiency particularly for part-load operation. Consider replacing oversized motors with correctly-sized units to be a better match for the application and load.

3. Re-energize belt driven motor drives to be direct drives ($)

• Direct drives can be more energy efficient than belt driven motors as there are less moving parts; this means lower energy costs and less maintenance.
• A direct drive motor means the load is directly connected to the motor, without mechanical transmission elements such as gearboxes or belt and pulley systems.
• If re-engineering the motors isn’t cost effective, consider ways of reducing the friction and the energy consumption penalty of the mechanical transmission elements e.g. within the belt system.
• Discuss opportunities with specialist suppliers.

4. Upgrade to more efficient, cleaner equipment ($$)

• Look for opportunities to replace old inefficient process equipment with modern equivalents.
• Reconsider how part load operation can be controlled efficiently. Choosing high spec, efficient and smaller modular units of equipment can make it easier to switch equipment on and off to meet demand.
• Look for opportunities to reduce levels of friction (which increases energy losses) within distribution systems; for example, use larger ducts and pipes to minimize distribution energy consumption.
• Look for opportunities to use more environmentally-friendly fuels and refrigerants, and low or zero local emissions heating and cooling systems.

5. Rethink die-back control set-ups to be more on-demand ($$)

• Some approaches to control part-load operation are based on a dieback control philosophy; for example, when a materials’ handling process waits a fixed time period before going into suspend mode or switching off after any material has passed through.
• Control time delays are usually set up to avoid any risk and to double-check the smooth operation of the process. However, this comes with an energy consumption penalty.
• The good news is that there are always opportunities to reconfigure control set-ups to be more ‘on-demand’ with near instantaneous on/off control, which can significantly reduce the energy consumption of the process. This usually works well with multi-motor based systems.
• Discuss opportunities with operations colleagues and trial possible ideas. Continually rethink control set-ups in line with delivering best value for operational requirements and continually challenge the controls set-ups.

6. Use nearby located waste heat or renewable energy sources ($$$)

• Enquire in the local area as to whether there are any opportunities to use, recover and recycle any locally generated waste heat and power; either to power the process, or heat the facilities e.g., using waste biomass that would have otherwise been disposed of.
• If proposing biomass CHP or heating systems, review the local medium-term availability and sustainable supply of the appropriate renewable fuel sources. In addition, consider the impact of any local air emissions from the combustion processes.
• For process heating requirements, also look at opportunities to integrate solar thermal or photovoltaics into building roofing systems.

7. Set-up continual improvement processes

• Early on in any rethinking and redevelopment process, set an energy effective vision including associated organizational policies, strategies, metrics and targets designed to drive continual improvement. For example, this can be applied to the use of motors as a motor management policy.
• Set up the basic strategic checkpoints to regularly review overall performance and drive further continual optimization and improvement.
• Make use of tools such as dashboards to regularly communicate progress. 
• Synthesize the design intent into a set of key principles, useful to significant energy users, who can then implement the better operational practices and behaviors required.

8. Report on how long you can go

• As part of any rethinking process, forecast operational energy and other utilities consumption; think about low, high, and most probable energy productivity consumption levels.
• Involve operations and facilitates colleagues in the process to ensure forecasts are more realistic. Use this information as part of the energy improvement process for both colleagues and operational best practices.
• Develop consumption models that will also help review new saving opportunities, and drive continuous continual improvement of operational practices and behaviors going forward.

SUMMARY

There are always many opportunities to reduce the utilities consumption of process systems using performance improvement techniques.

We find following the 5-R categories helps ensure that remedial measures are considered in an order which, not only ensures lowest overall cost, but also right sizes subsequent investments in new process technology.

Download

If you would like the downloadable summary checklist for this, please contact us.

• It’s in Microsoft Word, but it can easily be converted to another Word processer, such as Google Docs. It’s read-only, so you’ll have to save your version onto your own drive to be able to modify it.
• You can then modify and develop this simplified checklist to suit your needs as required. Complete it on line or print it out (but remember: think before you print!)

For more detail about developing an approach to optimizing the energy performance of process systems, check out ISO 50001 and other related standards.

Written by James Brittain and Monica Landoni