A product’s environmental friendliness considers energy use in manufacturing and consumption as well as in material resources and their reusability/recyclability. This article discusses how the Design for the Environment (DfE) process can shape the three main stages (production, consumption, and destruction) of the product lifecycle that must be considered when delivering a product to market. A case study demonstrates how DfE is applied to reduce the material and energy used in the product lifecycle of sustainable coffee maker.
Introduction: What is Design for the Environment?
Design for the Environment (DfE) is the process of investigating the possible environmental impacts of a product and refining the product design as necessary to reduce or negate the potential impacts (Lindhal, 2005). The environmental impact of a product covers a wide variety of potential topics. A product may harm the environment by containing non-renewable resources, or creating hazardous byproducts through its consumption. For example, improper disposal of electronics can leak lead, nickel, cadmium, and mercury into water supplies (EPA, 2012). According to the U.S. Environmental Protection Agency (EPA, 2012), “Recycling one million laptops [through material reclamation] saves the energy equivalent to the electricity used by 3,657 US homes in a year.” An electronic device’s ability to be recycled at the end of its lifecycle also plays a role in its environmental impact, as exemplified by the fact that “one metric ton of circuit boards can contain 40 to 800 times the amount of gold and 30 to 40 times the amount of copper mined from one metric ton of ore in the US.” Less mining means less energy consumed as well as less environmental disturbance in the region the mining is taking place. Other factors to consider in a products lifetime include the energy used to manufacture the product, the energy consumed by the product while employed, and the energy used to refine it into more raw material at the end of its lifecycle (if applicable).
More specifically, in the case of electrical engineering, DfE is concerned with the power drawn by the electrical product during the components operation, the time necessary to be active, and the recycling of the raw materials used to construct it at the end of its lifecycle. It is easy for a designer to complete the requirements of a circuit without much thought to power efficiency, unless the application involves a limited power source such as battery power or similar. However, with some effort, an electrical engineer may design hardware to require less power draw through lower voltage levels, or techniques such as pulse width modulation (Goldberg & Middleton, 2000). For many years, products have been designed to be recycled more easily, such as a reduction in the number of materials used, or a change to a more readily available material, or a material more suited for recycling. However, the recyclability of printed circuit boards and other electrical building blocks have had few changes to account for ease of recycling, due to their current level of simplicity, and due to the need to maintain familiar working properties. Hopefully, this will be addressed in the near future through developments in the field of materials science. To a greater extent, these products have been revised to contain fewer toxic elements, such as lead free solder, and alternatives to the brominated aromatic hydrocarbon flame retardants (Goldberg & Middleton, 2000).
DfE is most effective if implementation starts during the initial stages of product development. Through awareness of possible environmental impacts from the beginning, it is much easier to have the product design incorporate precautionary measures as opposed to revising the design in a later stage to prevent negative environmental impacts (Xueqing and Zhang 2009). Originally, products were not designed with the environment in mind because the consumer did not demand it, and businesses did not see it as a method to increase profits. However, the act of designing for the environment correlates with more efficient manufacturing and cheaper products. Thus, following the principles of DfE actually tends to increase a company’s profit margin in the long term.
The Three Stages of Eco-Efficiency Measurement for a Product
The lifecycle of a product may be split into three stages: production, consumption, and destruction. Within each of these three stages, there are techniques that may be employed to reduce the products environmental impact.
Stage 1: Production
In the production stage, a more efficient manufacturing process may translate into a more sustainable product. By choosing the correct materials, parts may be formed more efficiently, using less material. The thermoset plastic used as the base of a PCB is not difficult to recycle by itself, but the addition of a flame retardant, electronic components, filler such as glass fiber and silicone, copper pads and traces, ink, tape, labels, can all make it much more difficult to recycle the underlying plastic (Goldberg & Middleton, 2000). Thermoplastic plastics can be contaminated with glues, paints, labels, and solvents, which alter the properties of the substance to the extent that it becomes unrecyclable. For example, 1 pound of acrylic can render a 2000lb batch of recycled styrene unusable (Goldberg & Middleton, 2000). This can be overcome by limiting the amount of contamination to the thermoplastic, or by specifically labeling the contaminates in the plastic, so that it may be recycled together with plastic of the same contaminate proportions (Goldberg& Middleton, 2000). A reduction in the number of parts in the product may also reduce energy used to create the product. By modularizing a product, emissions may be cut from the production stage, and the cost of manufacturing may also be reduced (Xueqing & Zhang, 2009). In addition, a reduction in the variety of materials used to construct the product will make its recycling easier. A product that is easier to disassemble is also easier to recycle.
Stage 2: Consumption
During the main stage, the consumption of the product, the product design has the possibility of saving the most energy or releasing the fewest toxic or harmful materials. The product may be designed to only use as much energy as is necessary in its current state, effectively creating sleep and on modes, or any other variation necessary to be in the most efficient state at that moment. More specifically, use batteries that lose energy less quickly, reduce current and/or voltage demands in the circuitry, active power management to turn off segments of the electronics not in use, and combine functions in the ICs, so that less circuitry is required overall (Farnell, 2009). In the case of electronic hardware, little or no harmful materials are leaked into the environment during the consumption stage. However, other aspects of electronics must be considered in regard to people’s health, including the amount of radiated energy from a device. For example, studies have suggested that the electromagnetic field radiation from a cell phone can eventually cause brain cancer in humans who hold the cell phone to their head often, over many years (Aly et al., 2008)
Stage 3: Destruction
For the final stage, destruction, the components of the product must be thrown away, reused, or recycled. For most electronics, it is often not possible to reuse them, as they are not repairable. A typical printed circuit board will contain flame retardant, woven fiberglass with epoxy resin, copper, ceramic, silicon, aluminum, silver, gold and palladium (Appropedia, 2012). According to the EPA (2012), approximately 25% of TVs and 8% of cell phones were collected to be reused or recycled. It is more environmentally friendly for a higher percentage of the product to be able to be recycled. Many raw materials may be easily recycled on their own, but other materials used in conjunction may contaminate the recyclable material, rendering it unrecyclable (Goldberg & Middleton, 2000). It is possible to separate plastics from metal, and steel, aluminum and copper from each other. However, it is harder to separate the heavy metals from each other (Appropedia, 2012). Any products with heavy metals should be able to have these more toxic elements removed through similar processes (Appropedia, 2012). Batteries are a growing source of electronic waste, and when improperly disposed of, can leach heavy metals such as nickel, lead, mercury, and cadmium into the environment (Call2Recycle, 2013). The environmental impact of batteries can be reduced by using rechargeable batteries, for reuse, and properly recycling batteries at the end of their lifecycle. At recycling plants specifically designed for batteries, the heavy metals may be melted out of the batteries, distilled, separated, and then used as raw material (Call2Recycle, 2013).
Examples and Implementation
For the production stage, increasing the efficiency of the manufacturing process can be as straightforward as capturing heat from the manufacturing process to create steam, which can then be used to generate electricity (Gordon, 2012). In addition, making sure that manufacturing equipment is maintained appropriately or replaced when necessary will decrease energy use during the manufacturing process (Gordon, 2012).
In the consumption stage, a classic example of an energy saving strategy is the suspend-resume settings on PCs. In order to conserve power used by the PC and monitor, an advanced power management scheme was programmed into the BIOS of the computer, which entered the system into a low power state if no inputs had been used for a certain period of time (Goldberg & Middleton, 2000). This simple change helped customers with their electricity bills and reduced emissions from power plants that would have otherwise created the electricity to maintain the normal power state.
Another example of energy saving strategies for the consumption stage of a product is the use of pulse width modulation (pwm) in AC motors (Goldberg & Middleton, 2000). By pulsing the input voltage to a motor on and off quickly, the motor can be run at slower speeds when appropriate, as opposed to letting the motor always spin at a single speed.
In the destruction stage, designing products to be comprised of distinct functional units can help increase the reusability of products. For example, the Intel Pentium II processor comes in a single hard shelled case (Goldberg & Middleton, 2000). This modular design enables easier recovery or replacement of the entire processor unit, and easier recycling at the end of its lifecycle.
An example of a product not designed for recycling or reuse is the LCD TV. The screen is illuminated by a set of mercury lamps. These lamps should be removed so the rest of the parts will not be contaminated with mercury when shredded (or similar). However, the TV must be completely disassembled before the lamps can be removed (Electronics TakeBack Coalition, n.d.).
The Senseo Viva Café Eco reflects the attempt of Phillips (a major electronics firm) to make the most sustainable coffee maker possible. Following DfE principles in the construction stage, the body of the coffee maker is made from at least 50% recycled materials. Phillips takes materials that have been sent for recycling, groups them into different categories of plastics, and then compounds the material into a form ready to be shaped for the coffee maker. The eye-catching wavy texture of the top of the coffee maker is created from CD and DVD manufacturing waste. Applying DfE principle to the consumption stage, the standby time of the product has been reduced to 5 minutes, as compared to the industry standard of 30 minutes. The packaging of the coffee maker for shipping and display is also made from 90% recycled materials. Finally, using DfE principles in the destruction stage, the recyclable plastics employed in the construction of the Senseo will allow a large portion of the coffee maker to be recycled again at the end of its lifecycle (Philips, 2013).
Application to Senior Project
Our senior project is to design and construct a three dimensional metal printer. The construction of our project includes the metal structure used to create a cnc base and the welder used to serve as the printing head. For ease of reuse, the metal base should be easily deconstructed through a modular assembly. Our prototype base translation system has been constructed out of tetrix, an aluminum set of modular parts that can be deconstructed when the project is finished. The higher the accuracy of the printing head (achievable through more precise axis and wire feed control), the less deposited metal is wasted in printing the final product. In addition, proper computer control of the welder and base assembly will allow minimal use of electricity to melt the minimum amount of steel necessary to construct the desired item.
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