Introduction to Energy Efficiency in Industrial Systems

Welcome to this course on an introduction to industrial energy efficiency. I’m Bruce Rowse.

Industrial energy efficiency is a vast area, and this course will not be covering all areas of industrial energy efficiency. However we will be providing an introduction to four areas of industrial energy use that are common across many industries – electric motors, compressed air, steam and refrigeration.

The aim of this course it to help you identify opportunities to save energy in industrial systems, which is a process that covers.

1. Understanding how energy is used.

2. Understanding what the opportunities are to save energy, including applying the energy efficiency hierarchy

3. Developing a Sankey diagram to identify inefficiencies and wastage.

This process can be applied to any area of energy usage. And we will be applying it separately to each of the four areas of electric motors, compressed air, steam and refrigeration.

Each of these areas, in its own right, has a large body of knowledge associated with it. As this is an introductory course, it is focussed on giving you a preliminary understanding of these areas; if you wish to go beyond what we cover in the course there are links to additional resources throughout the lessons.

Before taking this course you should have completed the lessons in this series focussed on the processes involved in undertaking energy audits [hyperlink to the course on energy audit processes], and should also have completed other courses in the energy technology series, in particular the course on energy efficient HVAC [hyperlink to the HVAC course].

I hope you enjoy this course, and please don’t be shy to ask questions or post comments.

Motors are everywhere!

Thinking of just one day of your life, identify all the electric motors that have been used in the products and services you use. Write them down in the comment box.

Then watch the lesson video which looks at how motors work and the characteristics of AC induction motors, which easily account for the bulk of electricity used in motors globally.

In this topic we look at motor efficiency, and touch on opportunities to save energy.

The resources for this lesson provide more detail, please review the various links in the resources section.

In this lesson we develop a Sankey diagram for a water pump used by a water authority.

Note that when analysing systems using motors you need to understand the energy engineering of the different components of the system, and not just the motor. This may be a little complex if you are not familiar with the technologies, but its also a great way of helping you learn about, and understand, inefficiencies in systems.

In the next lesson it will be your turn to develop a Sankey diagram for a pumping system. So please follow this lesson closely, so you have a reasonable understanding of pumping systems.

Now its your turn to try! Please watch the video, then, using this table summarizing the data presented, build your Sankey diagram.

Once you’ve done this, undertake the quiz where you’ll need to upload your Sankey diagram, then go onto the next lesson where I’ll talk through my Sankey diagram for this problem

Please watch the video which presents the Sankey diagram.

You may have found this exercise a little challenging, as pump efficiency data wasn’t available and you would have had to reverse calculate it!

Congratulations on getting to the end of this section on motors.

Please watch the video which provides a summary of what has been covered.

Compressed air is widely used, and can be found in small mechanics shops right through to the very largest factories.

Before watching the video please identify some examples of what compressed air is used for. Write them down in the Q&A section.

Then watch the lesson video which looks at the components and characteristics of compressed air systems, and the energy in compressed air.

How efficient are compressed air systems?

The short answer is that they aren’t!

This lesson looks at more efficient alternatives to compressed air, and then, if the use of compressed air is unavoidable, looks at applying the energy efficiency hierarchy to identify opportunities to reduce wastage in compressed air systems.

In this lesson we will develop a Sankey diagram for a compressed air system used by a manufacturer.

This involves two steps – first determining the power available at different points in the system, then building the Sankey diagram.

Usually at this point in a lesson I would be asking you to developing your own Sankey diagram for a compressed air system.

But in this case I’m going to ask you to come up with a business case for replacing the 200 actuators in the previous example, with 200 electric actuators.

Please determine the simple payback, and net present value of the upgrade.

Then in the next lesson I’ll present a calculated solution.

Please watch the video, which develops and presents the business case solution.

In this brief introduction to compressed air we’ve looked at the components and characteristics of compressed air systems. We have identified that there is no such thing as an energy efficient compressed air system.

We stepped through the energy efficiency hierarchy and developed a Sankey diagram, showing that the key opportunity with compressed air systems is to eliminate the use of compressed air.

If its not possible to eliminate the use of compressed air there are still good savings opportunities possible.

Identifying these opportunities involves developing a good understanding of the system, and what compressed air is used for.

The energy efficiency hierarchy is a useful tool for identifying compressed air opportunities – and the resources presented provide a lot of detailed information on compressed air systems. If you are willing to develop a good understanding of compressed air, and can undertake detailed site investigations, it may be possible to achieve very significant savings.

The industrial revolution started with steam boilers, and whilst its unusual to come across steam systems, they still play an important role in many industries.

Before watching the video please identify some examples of what steam is used for. Write them down in the Q&A section.

Then watch the lesson video which looks at the components and characteristics of steam systems.

After watching the video please take the quiz for this lesson before moving on to the next topic.

This topic examines the energy efficiency of steam systems, and introduce opportunities to save energy.

There is a lot of energy lost in steam systems. For a steam system providing heat, a typical efficiency is around 30% to 50%. Or in other words, only 30% to 50% of the energy in the fuel source ends up as providing useful process heat.

So why are steam systems not efficient?

Put your answer in the Q&A section then watch the video for this lesson.

In this lesson we develop a Sankey diagram for a steam system in a hospital.

Please watch the video to learn how the calculations of energy at various points have been undertaken, and then this information used to build the Sankey diagram.

Usually at this point in a lesson I would be asking you to developing your own Sankey diagram for a steam system.

But in this case I’m going to ask you to reflect on the example in the previous lesson – the hospital steam system - and then to apply the energy efficiency hierarchy to this facility to identify what you might do to reduce the use of steam.

Please use download the Energy Efficiency hierarchy template in the resources section. Then complete it. I suggest you review the information from the previous lesson and its Sankey diagram.

For easy reference use the hospital steam schematic picture found in the resources section.

Try and identify as many opportunities as possible. Then upload your completed hierarchy in the quiz for this lesson. Following that, in the next lesson I’ll then present the EE hierarchy I developed for this system.

You’ll find in the resources section my energy efficiency hierarchy for this system.

In this lesson I want to focus on the first element of hierarchy – eliminating the need for the service.

Watch the video to learn about this!

In this brief introduction to steam we’ve looked at the components and characteristics of steam systems. We have identified that steam systems can have large losses, particularly under conditions of low loading.

We stepped through the energy efficiency hierarchy and developed a Sankey diagram, and illustrated that in applications where the end service requires temperatures of less than 100OC, eliminating steam completely can lead to large savings.

If its not possible to eliminate the use of steam there are still savings opportunities possible. Identifying these opportunities involves developing a good understanding of the system, and what steam is used for. Ensuring high boiler operational efficiency and effective maintenance of the steam system are well-known opportunities.

The energy efficiency hierarchy is a useful tool for identifying steam opportunities – and the resources presented provide a lot of detailed information on compressed air systems. If you are willing to develop a good understanding of steam, and can undertake detailed site investigations, you should be able to identify very significant savings opportunities – although perhaps not at all sites – good steam installations do exist (!).

Thanks for taking this section on steam systems!

Modern life would not be possible without refrigeration! At least once today you have probably benefitted from refrigeration.

Before watching the video please identify some examples of where refrigeration is used. Write them down in the Q&A section.

Then watch the lesson video which looks at types of refrigeration systems, how they differ from air conditioning systems, and characterising the main components.

Ammonia, which is the most widely used refrigerant in industrial refrigeration is also examined.

After watching the video please take the quiz for this lesson before moving on to the next topic.

In this topic the energy efficiency hierarchy is used to identify energy savings opportunities with refrigeration systems.

Now its your turn! Please watch the video, looking at refrigeration in a small supermarket. Then, using the energy efficiency hierarchy, identify opportunities to reduce refrigeration energy use.

The video for this lesson talks through my energy efficiency hierarchy for this system.

In the resources for this lesson you’ll also find the hierarchy I developed.

In this brief introduction to refrigeration we’ve identified the importance of understanding the vapour-compression refrigeration cycle, which was presented in detail in the course on HVAC energy efficiency.

Refrigeration systems are required to deliver lower temperatures than air conditioning systems, and often the cooled enclosure is considered part of the refrigeration system.

We stepped through the energy efficiency hierarchy to identify a range of savings opportunities, and referred to a range of resources providing more detailed guidance.

Identifying these opportunities involves a good understanding of the vapour compression cycle, along with knowledge of the many varied types of refrigeration systems. Refrigeration systems can get quite complex when there is more than one stage of refrigeration, and different refrigerants can have quite different characteristics, each with their own area of specialist knowledge.

Perhaps similar to HVAC systems, good maintenance of refrigeration systems is a valuable energy efficiency measure.

Thanks for taking this module on refrigeration, and I hope you’ve learnt from it!

Thanks for taking this course on industrial systems!

The video for this lesson briefly steps through the main messages presented in relation to motors, compressed air, steam and refrigeration.

Across all these systems don’t be shy to consult experts who specialize in those systems, particularly when you can’t eliminate the need for the service.

If you’ve completed other courses in this series, and passed all the quizzes, you only have one more task now to become a certified investment grade energy auditor – which is undertaking an energy audit and submitting it for assessment!

We look forward to you taking on the task and reviewing your energy audit!

And please also rate and leave a review for this course.