当我还是个孩子的时候,我们有一个主持人烤面包机。它was, as the ad says, "Lovely to look at, delightful to use, sure to endure." I think my mom still has it and still works. But being "a combination of classic beauty, perfect product performance and remarkable time-defying endurance" (yes, the ad says that too) is no longer what drives product design; now it is to be sold in Walmart for five bucks, in itself a remarkable story of manufacturing and retailing efficiency.
The five dollar toaster and the 50 year toaster are both laudable goals, but when it comes to greenhouse gas emissions and getting off oil, they are two very different things.
Thomas Thwaite'sToaster Project
The old Toastmaster was a simple well-built product, but as we learned from art student Thomas Thwaite, nothing is as simple as it looks. He built one from scratch, and learned its true cost, in labour and environmental footprint. He concluded:
"We either have to value what we've got a lot more, or spend as much time and effort taking things apart and disposing of them as we do putting them together."
The toaster is a great example of how we can take a simple concept, a device that can last a generation, and turn it into a cheap throwaway. Or, designers can add useless functions and adopt strange forms, making it complex, expensive and silly.
Whether you are talking about a toaster or an iPhone or an office building, the same principles apply. We have to look at the whole picture: how much energy went into the things we make, how much energy it takes to run them, how appropriate is the energy source for the purpose, how long it lasts, and what happens at the end of its useful life.
More technically, we have to look at its embodied energy, its operating energy, its exergy and its durability, and wrap it all together in a life cycle assessment.
Othmar Mulebach's"Printing Your Toast"
Embodied energyis the non-renewable energy consumed in the aquisition of raw materials, their processing, manufacturing and transportation. Some materials take a huge amount of energy to make and have a big carbon footprint because of it; new aluminum tops the list at 227 megajoules per kilogram, compared to lumber at 2.5 MJ/kg or concrete at 1.3 MJ/kg. But even that is not a good measure, because concrete is heavy and aluminum is not, and you have to figure out how much of it you are using per square foot of building; concrete then looks a lot worse.
For buildings, embodied energy is relatively simple to figure this out. But what about that iPhone or notebook computer?
Kris De Decker ofLow Tech Magazinelooked at the embodied energy of electronics and had a hard time of it; there isn't much data and technology moves so quickly. But in general, he reported that "while the ratio of fossil fuel use to product weight is 2 to 1 for most manufactured products (you need 2 kilograms of fuel for 1 kilogram of product), the ratio is 12 to 1 for a computer (you need 12 kilograms of fuel for 1 kilogram of computer)." It takes a lot of energy to make those chips, and "our digital technology is a product of cheap energy."
Inseq Design'sZuze Toaster
Operating Energyis the easiest number to understand; what it takes to run our buildings and our iPhones. If we are going to get off oil, the key is to switch from non-renewable to renewable resources.
Sasha Tseng'sNotepad Toaster
Exergyis defined in theCanadian Architect's Measure Of Sustainabilityas Energy Quantity X Energy Quality, the matching of the source of our energy with the function it serves. For example, an electric hot water heater: We burn coal to boil water to spin a turbine to drive a generator, then we push the electricity down wires and through transformers- to boil water. Dumb, when a solar water heater on the roof could do it for free without any carbon footprint at all.
The iPhone, on the other had, has fabulous exergy; it uses the highest quality energy in very small quantities.
Thinking about exergy could be one of the most important things architects and designers do if we are going to get off fossil fuels.Canadian Architectwrites:
From an exergy efficiency perspective, building technologies which rely on solar, wind and biomass energy sources, coupled to thermally efficient envelopes, appropriate fenestration strategies [where we put what kind and size of windows] and natural ventilation/cooling are truly more elegant than "cutting butter with a chainsaw." Exergy efficiency remains to be fully considered by mainstream architectural science research and development initiatives, however it may be expected to gain importance as a critical measure of sustainability.
George WatsonsGlide Toaster
Durabilityis ultimately the most important factor in determining the total footprint of an object, and why we have to build like Toastmasters rather than the $5 Walmart toaster. Because to find the real energy consumption of a house or an iPhone, we have to know the embodied energy + the operating energy and divide it by the lifespan.
Kris De Decker,after analyzing the energy density of manufacturing our computers and (12 kilograms of fuel per kilo of computer) calculates that the embodied energy in the manufacture of just the RAM in a notebook computer would run the thing nonstop for a thousand days.
Or let's take an iPhone. It weighs 137 grams and probably has half of its weight in semiconductors, or 65 grams. Chris calculates that it takes 800 kg of fuel for 1 kg of semiconductor, so that's 52 kg of fuel, or 650 kilowatt-hours of electricity. The average cellphone has a two year contract and the average use is 459 minutes per month; iPhone users use triple that with data, or 1,377 minutes per month or 550.8 hours per contract. You may not think that iPhone uses much electricity, butit is burning through 1180 watts of embodied energy every hour it is used.
The iPhone has a huge embodied energy density and a short life. What about a house or a building?
A single family house has an embodied energy of roughly700 MBTU per square foot;The average house burns through 61 MBTU of energy per square foot per year. (Source pdf) The construction of the house is equivalent to 11.47 years of operating energy use. But it probably lasts 50 years, so it is burning through 14 mbtu per square foot per year during its much longer life, or 463 watts per hour, half of the iPhone.
If we look at the embodied energy, the exergy and the operating energy, the basic lesson for iPhones and houses are the same: Take care of it and make it last. For our homes and buildings, where we have a little more control than we do with iPhones, there are other lessons:
- Build to last, with low maintenance materials.
- Build less. Smaller homes use less material with lower embodied energy and use less energy to heat.
- Repair and renovate instead of demolishing and replacing.
- Reduce complexity; simple systems last longer.
- Design for repair and deconstruction; think about how it comes apart as well as how it goes together.
- Pick materials with low embodied energy.
- Design to maximize exergy; use passive solar and natural ventilation instead of electricity and fossil fuels. Save electricity for electronics and lighting (and toasters). Insulate and seal like mad.
Chris Naylor'sInvader Toaster
简单的主持人是基业常青,mechanical components, for ease of service at a reasonable cost. The designers of every other toaster (and most architects) on this page could learn lessons from it.