Principles and Practices in Sustainable Development for the Engineering and Built Environment Professions 

Unit 2 - Efficiency/Whole System

 

Lecture 7: Achieving Whole of Systems Optimisation: Pipes and Pumps

         

Consciously or not, engineers mould the future. The technologies they design and develop will shape both work and leisure. The values they bring to their professional lives will play a part in determining the extent to which these technologies enrich or impoverish the lives of those they touch.

Johnston et al, 1995[1]

Educational Aim

 

To introduce RMI’s Pipes and Pumps case study as an existing whole system engineering example of redesigning industrial pumping systems, where optimising the whole of the system for multiple benefits can yield Factor 4 – 10 productivity improvements. To also show how this case study can be emulated for the Whole System Design (WSD) of numerous other engineering systems. Few people or organisations have done as much as Amory Lovins and RMI to communicate the benefits of whole of system engineering design (WSD) to engineers. This case study is therefore provided as a tribute to their leading work.

 

Required Reading

The Natural Edge Project (2007) Engineering Sustainable Solutions Program: Design Principles Portfolio – Whole System Design Suite, The Natural Edge Project, Australia, Case Study 1: Industrial Pumping Systems. Available at www.naturaledgeproject.net/Whole_Systems_Design_Suite.aspx. Accessed 5 January 2007.

Hargroves, K. and Smith, M.H. (2005) The Natural Advantage of Nations: Business Opportunities, Innovation and Governance in the 21st Century, Earthscan, London:

1. Chapter 1:Progress, Competitiveness and Sustainability (5 pages), pp 7-11.
   
   
   

Learning Points

1. In Natural Capitalism, Hawken, Lovins and Lovins highlighted a series of actions critical to successfully implementing Whole System Design (WSD):[2]

1. The whole system should be optimised.
   
   
2. All measurable benefits should be counted.
   
   
3. The right steps should be taken at the right time and in the right sequence.
   
   
4. Turn compounding losses into savings.

2. The authors of Natural Capitalism used the case study of pipes and pumps to illustrate the importance of these actions. As Amory Lovins from RMI writes,[3]

From the power plant to an industrial pipe, inefficiencies along the way whittle the energy input of the fuel - set at 100 arbitrary units in this example - by more than 90%, leaving only 9.5 units of energy delivered to the end use. Small increases in end-use efficiency can reverse these compounding losses. Hence by focusing on end use efficiency it can create a cascade of savings all the way back to the power plant.

3. An engineer Jan Schilham succeeded in doing just this. In 1997, leading American carpet maker Interface Ltd was building a factory in Shanghai. One of its industrial processes required fourteen pumps. In optimising the design, the top Western specialist firm sized those pumps to total ninety-five horsepower.

4. But a fresh look by Interface/Holland's engineer Jan Schilham, applying methods learned from Singaporean efficiency expert Eng Lock Lee, cut the design's pumping power to only seven horsepower - a 92 percent or twelve-fold energy saving - while reducing its capital cost and improving its performance in every respect.

5. The new specifications required two changes in design. First, Schilham chose to deploy big pipes and small pumps instead of the original design's small pipes and big pumps. Friction falls at nearly the fifth power of pipe diameter, so making the pipes 50 percent fatter reduces their friction by 86 percent. The system then needs less pumping energy - and smaller pump motors to push against the friction. If the solution is this easy, why weren't the pipes originally specified to be big enough?

6. Because of a small but important blind spot: Traditional optimisation compares the cost of fatter pipe with only the value of the saved pumping energy. This comparison ignores the size, and hence the capital cost, of the equipment - pump, motor, motor-drive circuits, and electrical supply components - needed to combat the pipe friction. Schilham found he needn't calculate how quickly the savings could repay the extra up-front cost of the fatter pipe, because capital cost would fall more for the pumping and drive equipment than it would rise for the pipe, making the efficient system as a whole cheaper to construct.

7. Second, Schilham laid out the pipes first and then installed the equipment, in reverse order from how pumping systems are conventionally installed. Normally, equipment is put in some convenient and arbitrary spot, probably just like the last one, and the pipe fitter is then instructed to connect point A to point B. The pipe often has to go through all sorts of twists and turns to hook up equipment that's too far apart, turned the wrong way, mounted at the wrong height, and separated by other devices installed in between. The extra bends and the extra length make friction in the system about three- to sixfold higher than it should be.

Figure 7.1. Long, thin, crooked pipes
Source: Amory Lovins (2003)[4]

8. By laying out the pipes before placing the equipment that the pipes connect, Schilham was able to make the pipes short and straight rather than long and crooked. That enabled him to exploit their lower friction by making the pump motors, inverters, and electricals even smaller and cheaper. The fatter pipes and cleaner layout yielded not only 92 percent lower pumping energy at a lower total capital cost but also simpler and faster construction, less use of floor space, less noise, more reliable operation, easier maintenance, and better performance.

9. As an added bonus, easier thermal insulation of the straighter pipes saved an additional 70 kilowatts of heat loss, enough to avoid burning about a pound of coal every two minutes, with a three-month payback. Fat, short, straight pipes - not skinny, long, crooked pipes!

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Brief Background Information

 

In Natural Capitalism, Hawken et al highlighted a series of actions critical to successfully implementing Whole System Design (WSD):[5]

• The whole system should be optimised.
  
  
• All measurable benefits should be counted.
  
  
• The right steps should be taken at the right time and in the right sequence.
  
  
• Turn compounding losses into savings.
  
  

1. The whole system should be optimised – all parts of the system (sub-systems and single elements) should be considered when optimising the engineering solution. Changing the properties of one part of the system will affect the properties/behaviour of other parts of the system, which would be undesirable if other parts of the system are already functioning optimally. Therefore parts of the system optimised in isolation can lead to sub-optimal design for the system as a whole.
   
   
2. All measurable benefits should be counted – systems optimised for one parameter only (e.g. lower energy consumption) usually miss out on a range of benefits available through Whole System Design. For example, successful WSD can not only reduce energy consumption of a manufacturing process, but improve productivity, reduce safety and health risks, improve reliability, reduce maintenance, and improve employee workplace conditions. Multiple benefits can lead to compounding savings and productivity improvements.
   
   
3. The right steps should be taken at the right time and in the right sequence – Whole System Design carefully defines the system structure by determining what should be considered at each step of the process to yield maximal resource productivity. The right sequence is vital as early design decisions influence the performance of the rest of the system.
   
   
4. Turn compounding losses into savings - 90 percent of energy created at the power station is virtually lost through compounding inefficiencies within the existing electricity infrastructure (i.e. the power plant, grid, transformers etc.) before it reaches the end user.[6] Hence, since energy losses compound, so should energy savings! Saving one unit of electricity at a pump will ultimately save 10 units of fuel at the power plant (as well as cost and environmental impacts), see Figure 7.2 below.[7]

Figure 7.2. From the power plant to an industrial pipe, inefficiencies along the way whittle the energy input of the fuel - set at 100 arbitrary units in this example - by more than 90 percent, leaving only 9.5 units of energy delivered to the end use
Source: Amory Lovins (2005)[8]

By focusing on end use efficiency it can create a cascade of savings all the way back to the power plant. This is why an engineering focus on whole system (re)-designing to re-optimise ‘end use’ engineered systems such as motors, HVAC systems, buildings, and cars can help business and nations reduce environmental pressures significantly. By focusing on these engineered systems, which actually provide the services we need - close to the end user, big savings can be achieved.

Consider motors for a minute, motors use about 60 percent of the world’s energy,[9] and those used in pumping applications use about 20 percent of the world’s energy.[10] So if it is possible to reduce the amount of energy that a motor system needs this will create a cascade of savings all the way back to the power plant. Whole System Design resource productivity gains can be achieved while also reducing significantly the running costs of the system. The total life cycle cost of a typical pump is distributed 5 percent to capital costs, 10 percent to maintenance and 85 percent to energy consumption.[11] So by reducing the energy consumption for the operation of the equipment by 92 percent significant cost savings can be achieved. The old idea was to ‘optimise’ only part of the system - the pipes - against only one parameter - pumping energy. Schilham, in contrast, optimised the whole system for multiple benefits - pumping energy expended plus capital cost saved. Optimising the whole system both for resource efficiency and cost benefits yields hidden sources of wealth.

This is archetypical: applying WSD principles to almost every technical system – HVAC systems, motors, lighting, buildings, cars, refrigerators, computers - yields ~3–10x energy/ resource savings, and usually costs less to build, yet improves performance. When most designs are complete, but still before they have been built, about 80-90 percent of their lifecycle economic and ecological costs have already been made inevitable. For all these reasons businesses, corporations and governments should all be interested in Whole System Design.

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Key References

- For more information on the theory behind systems thinking and Natural Capitalism’s Principles of Whole System Design,

- The Role of Engineering in Sustainable Development A – Unit 2: Learning the Language, Lecture 8: The Role of Systems.

- Hargroves, K. and Smith, M.H. (2005) The Natural Advantage of Nations: Business Opportunities, Innovation and Governance in the 21st Century, Earthscan, London.

- Hawken, P., Lovins, A.B. and Lovins, L.H. (1999) Natural Capitalism: Creating the Next Industrial Revolution, Earthscan, London, Chap 6: Tunnelling Through the Cost Barrier. Available at http://www.natcap.org/images/other/NCchapter6.pdf. Accessed 5 January 2007.

- Rocky Mountain Institute (n.d.) Efficient Pump Systems. Available at http://www.rmi.org/sitepages/pid298.php. Accessed 5 January 2007.

- von Weizsacker, E., Lovins, A.B. and Lovins, L.H. (1997) Factor 4: Doubling Wealth – Halving Resource Use, Earthscan, London, pp 53 – 57.

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Key Words for Searching Online

Motor efficiency, life cycle cost, variable speed drive, pipe friction, end use efficiency.

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[1] Johnston, S., Gostelow, P., Jones, E. and Fourikis, R. (1995) Engineering and Society: An Australian Perspective, Harper Educational, Sydney, p xvii. (Back)

[2] Hawken, P., Lovins, A.B. and Lovins, L.H. (1999) Natural Capitalism, Earthscan, London, Chap 6: Tunnelling Through the Cost Barrier. Chapter freely downloadable at www.natcap.org/images/other/NCchapter6.pdf. Accessed 5 January 2007. (Back)

[3] Ibid, p 121. (Back)

[4] Provided from personal liaison with Amory B. Lovins, CEO-Research, Rocky Mountain Institute, www.rmi.org. (Back)

[5] Hawken, P., Lovins, A.B. and Lovins, L.H. (1999) Natural Capitalism, Earthscan, London, Chap 6: Tunnelling Through the Cost Barrier. Chapter freely downloadable at www.natcap.org/images/other/NCchapter6.pdf. Accessed 5 January 2007. (Back)

[6] Hawken, P., Lovins, A.B. and Lovins, L.H. (1999) Natural Capitalism, Earthscan, London, Chap 6: Tunnelling Through the Cost Barrier. Chapter freely downloadable at www.natcap.org/images/other/NCchapter6.pdf. Accessed 5 January 2007. (Back)

[7] Ibid. (Back)

[8] Lovins, A.B. (2005) ‘More Profit with Less Carbon’, Scientific American, September 2005. (Back)

[9] Hawken, P., Lovins, A.B. and Lovins, L.H. (1999) Natural Capitalism: Creating the next industrial revolution, Earthscan, London, p 115. (Back)

[10] Lamb, G. (2005) ‘User’s guide to pump selection’, WME Magazine, July 2005, pp 40-41. (Back)

[11] Ibid. (Back)

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