My last article centered on innovation and sustainability – or creating “new” value – and the role of green innovation in product design and manufacturing. Recently I’ve been reading about, and hearing about, “frugal engineering,” or, it is sometimes referred to, as “frugal innovation.” As an engineer I’m happy to have the terms innovation and engineering used interchangeably.
Frugal engineering usually refers to reducing the complexity and cost of some good and the production of it so that, for example, it might be more accessible in developing economies. Wikipedia defines frugal engineering in this way and states that the term “refers to removing nonessential features from a durable good, such as a car or phone, in order to sell it in developing countries. Designing products for such countries may also call for an increase in durability and selling them, reliance on unconventional distributions channels. Sold to so-called “overlooked consumers”, firms hope volume will offset razor-thin profit margins. Globalization and rising incomes in developing countries may also drive frugal innovation.”
Importantly, the result of frugal engineering is not products (or processes) with inferior quality. But there is an emphasis on low cost of product. So, to insure reasonable margin, production must be similarly efficient.
There is always a tension between “built to last” and “built to last long enough!” This becomes a major issue in closed loop systems such as those illustrated with the Ricoh Comet Circle and other closed loop scenarios. We covered the comet circle some time ago. (And from Ricoh). The comet circle, shown below from Ricoh,
shows both the forward and reverse logistics path we’ve discussed before – material flowing via the product to the consumer and then material flowing to other uses after product use by the consumer. The “most sustainable” here is the loop that goes back to the consumer with the same product providing the same function. The challenge of “built to last” vs “built to last long enough” plays an important role here. Products with long lives will be more reasonably returned to similar use at a similar functional level. Products which fail, or the obnoxious subset of failure, being overcome by new technology, will have longer loops and, by definition, be less sustainable.
So, how do we decide where is the “sweet spot” between designing products (made of components) that last a long time vs those that fail earlier. One critical question is “should we design (and make) all the components to fail at the same time and incur the extra cost and, likely, over design, or should we let one or more components fail earlier and then reuse the remaining components as with remanufacturing?
Engineers have been dealing with the tradeoff between product design, quality and failure for a long time. This is usually discussed as part of product reliability. Dennis Wilkins (retired from HP) explains that reliability engineers characterize the lifetime of a population of products using a graphical representation called the “bathtub curve.” The bathtub curve is characterized by three periods in a product life: an infant mortality period (early failure)
with a decreasing failure rate, then a normal life period (also known as “useful life”) with a low, relatively constant failure rate, and ending up with a wear-out period of accreted failure exhibiting an increasing failure rate. Engineers try to reduce failures at each stage of product life by efforts such as “burn-in” or running the product for some time to catch early failures or other tests to attempt to screen out infant mortality failures. Design and manufacturing choices can reduce (or increase!) failures at any stage – depending on quality of components and design and production.
Professor Sami Kara and colleagues at the University of New South Wales in Australia have studied this problem, as applied to appliances, for some time. The studies explore the useful life of components with the thought to identifying those that have significant use in a second life versus those that fail with the appliance. This can drive the economic models for re-manufacturing but is dependent on simple ways to estimate which components have life left and, importantly, how to assess this easily and reliably. Challenges include the cost of testing procedures that might increase labor costs for remanufacturing or re-use, necessity for disassembly of an appliance to access the component to assess its condition, inaccurate test data with respect to condition, degradation or remaining life and questions about number of samples that need to be tested to get reliable data.(see “Reliability assessment of components in consumer products – a statistical and condition monitoring data analysis strategy” by Mazhar, Kara and Kaehernick, 2005).
Kara describes some of their studies showing that some very inexpensive components of large appliances fail early and render the appliance unusable – and often it would be very inexpensive to improve these components for a dramatically longer product life. One that comes to mind is the door seal on a residential refrigerator. But when is “good enough” for a product component good enough?!
So, that’s one consideration in design, production and life of the product.
Another consideration is product efficiency improvements resulting from new technologies. If product technology (in tens of operating energy or resource consumption) changes rapidly it might be advantageous to upgrade products (meaning change and replace) more often. Alternately, if product technology evolves slowly, there may be little advantage, from a consumption angle, to upgrading. The tipping point is with respect to embodied energy in the product.
Julian Allwood, who’s been mentioned before in this blog, covers the tradeoff in his book Allwood and Cullen, Sustainable Materials with Both Eyes Open, UIT, Cambridge, 2012. There are two distinct strategies depending on whether or not the product has “high embodied energy” or “low embodied energy”. Recall that embodied energy is the energy (and resources with their energy footprints) required to manufacture the product. Products with high embodied energy and low energy in use are candidates for replacement less often with technology enhancements while product with low embodied energy and high energy in use with improving efficiency are candidates for replacement more often as seen below. The strategy can have a big impact on the cumulative emissions (as from the energy) over the life
cycle of the product. This was the issue we discussed some time ago with respect to the “cash for clunkers” program as part of the recovery – it would be advantageous, from an environmental angle, to replace an old car with a newer car only if the newer car had sufficiently better fuel economy to offset over its life the embedded energy of the vehicle it was replacing plus save fuel.
Enough to consider for the moment. I’ll pursue this more with respect to frugal engineering and green in the next article.
David Dornfeld is the Will C. Hall Family Chair in Engineering in Mechanical Engineering at University of California Berkeley. He leads the Laboratory for Manufacturing and Sustainability (LMAS), and he writes the Green Manufacturing blog.
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