Less Can Be More
My father had an interesting expression he would bring out when my brother and I would be worried about something or, more likely, be interested in a “short term gain” in some venture. And, mind you, he lived through the depression and many years in the Army Air Force during the war in the Pacific so had the authority to use these kinds of expressions.
He’d remind us “as you wander down life’s highway, whatever be your goal, keep your eye upon the donut, and not upon the hole.”
I always liked that and believed it put a lot of things in perspective as one’s career moves along. I’ve used this from time to time when the situation seems relevant.
But, I found an exception to this wise advice … or I think I found an exception. We recently spent some time on a vacation trip to the Grand Tetons and Yellowstone National Parks in Wyoming. Along with the impressive scenery (and impressive amount of snow still around at this late date in June) I was also struck by the efforts of the concessionaires (those who run the lodging, shops and restaurants) in these parks to “go green.”
One in particular, Xanterra (they are a descendent of The Fred Harvey company), in Yellowstone has taken this very seriously. They even have a sustainability report on their corporate website and state that they are working to reduce their footprint in “energy, carbon emissions, waste, development, foods, transportation, and water.”
This is good. There is nothing more troubling, to me at least, than wasting a lot of fuel, water, electricity to see nature while trying to live greener.
So, the hole.
One of the things Xanterra puts in the rooms in their lodges in Yellowstone, Grand Canyon, Zion, Crater Lake, etc. is bath soap with a hole in the center! They call it “waste reducing exfoliating body cleanser” – but it’s soap.
The soap is called Green Natura (see the website if you don’t believe me) and the package, made of recycled materials and printed with soy inks of course, says that the soap is “ergonomically shaped waste reducing” and has been designed to “eliminate the unused center of traditional soap bars.”
So, this is neat. It has the size and shape of a more standard bar of soap without all the material that usually gets wasted/thrown away after a stay in a hotel. I like that. I know I should use the liquid soap dispensers in many bathrooms/showers which leave nothing (except the dispenser, etc.) to be wasted but there is something enjoyable about using a real bar of soap. I must note that there are some “other opinions” about whether or not this is really green (see, for example, the green soap site.) But, for the moment, let’s focus on the hole!
Unfortunately my father is not around to see this product … it might cause a ripple in his “don’t watch the hole” adage. But, to be fair, he never threw away the center of the soap. In our family there was no wasted soap – you just stick the last bit on top of the new bar and get on with it.
This, of course, does not work in hotels.
In this case, removing unused/un-needed/unwanted material is good. Actually, you might have seen this before in your undergraduate engineering studies (if you are an engineer!) where you learned to design simply supported beams with varying cross-sections to accommodate moments due to loading that cause the moment to be greater at the mid-span than at the ends. Making the beam of uniform shape along its length would add unnecessary weight and waste material.
There are better examples for real products, like automobiles, that tie into our green discussion. According to what I’ve seen recently, a new GM car, the Cruz ECO, has higher gas mileage due to reduced weight among other improvements.
The Cruz Eco article posted on Motley Fool (and based on an article by Wolfgang Gruener, of Conceivably Tech titled “Chevy Cruze Eco: 58 MPG, No Hybrid Magic”) has shown remarkable fuel economy for a “conventional” internal combustion engine vehicle. According to the article the most significant changes implemented in the Eco are:
• Weld flanges reduced 1 mm to 2 mm in length
• Metal gauge thickness reduced by 1 mm
• Lightweight 17-inch wheels
• Low-resistance tires
• Revised gear ratios (particularly first, second, and sixth gears).
• Unique front fascia with deeper front air dam
• Electronically controlled front air shutter that closes at higher speeds to reduce drag
• Metal pans below the car to improve air flow
• No spare tire (!)
• Lowered suspension
• Trunk-lid spoiler
The article states that these changes reduce the vehicle weight by 125 pounds (compared to 3,134 pounds for the Cruze LS) and 214 pounds less than the Cruze 1LT. Also, according to GM, the reductions in things like weld flanges saved several pounds and smaller wheels save 21 pounds compared to the 1LT version. Other improvements dealing with aerodynamics reduced the Eco’s drag coefficient by about 10% below the other Cruze models. That means it can move through the air with less resistance – better gas mileage.
The article states that all these changes resulted in a notable improvement in fuel efficiency. In tests run by the author of the article, stop-and-go driving yielded 32.3 MPG, and suburban driving with a mix of streets ended up at 39.8 MPG. Extremely careful cruising on the interstate at exactly 55 MPH resulted in a “stunning” 57.9 MPG.
You might recall an article about precision manufacturing and green. In that article, we discussed a Boeing example of tolerances (posted under the title “Little things matter“). A reduction in machining tolerances from +/- 0.006 inches to +/- 0.004 inches on the features of an airframe accounted for a weight reduction of 10,000 pounds/aircraft and substantial fuel savings (8%). This allowed an increase of 10% in passengers (engines don’t need to carry as much plane), and substantial reduction in manufacturing cost of the aircraft (less material and improved assembly). And less fuel consumption means reduced CO2 impact from operation.
So, we’ve seen examples of this before.
This clearly shows some nice leveraging of manufacturing but this leads to a follow on set of questions:
– can we do this more generally for manufacturing processes/machinery/tooling as well?
– what kind of analytical or engineering tools can we use to formalize the design of such processes/machinery/tooling?
We’ll focus on that in my next article, part 2 of “keep your eye on the hole.
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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