In those years, there have several important directives introduced by European Union( EU) in recent years most of them have forced to the manufacturers and producer EU's whom have to take the responsible and pay effort to reduce the environment impact of their product. Since the EU directive on Electrical and Electronic Equipment (WEEE) required manufacturers to recycle greater that 50% of the total mass of a product by 2006. WEEE is one of the EU directives which will tightly control the end-of life use of main consumer electrical products. This Directive aims to reduce the waste arising from electrical and electronic equipment and to improve the environmental performance of all those involved in the life cycle of these products.
Environmental impact reduction become a trendy in the world, we trust that most of the electronic project should meet the environmental impact reduce requirement in near further year.
In the European Union where the annual quantity of electronic waste is likely to double in the next 12 years, the European Parliament recently passed legislation that will require manufacturers to take back their electronic products when consumers discard them. This is called Extended Producer Responsibility. It also mandates a timetable for phasing out most toxic substances in electronic products. ( as Figure 1.2.a)
Above table showing a serious growth rate of E waste in further, spending the Kids' Inheritance if the environmental impacts cannot be reduce.
On the other hands, Green Council of Hong Kong do a consumer green product survey in 2007, in 654 interviewees, 75% of them willing to pay more to purchase a product which is label as eco- product. (Information from Green Council)
Consumer demand on environmental friendly goods had identified by Ryan et al. (1990 P.1) as key factors in the greening of international market.
"It is competitiveness in a new green market, where consumer action is express both through boycotts of undesirable goods and demand for 'environmentally friendly ' goods, that appears to underpin a real change in assessment of the importance of environmental quality for further industry direction "
This factor is also highlighted by Welford (1994 p.8), who states that:
"Consumers are increasingly willing to switch to products which are in some way more environmentally friendly than their normal purchase. Companies therefore need to demonstrate that their product and their processes cause minimum harm to the environment."
Due to market Motivation, our company is planning to label WEEE to our transformer product; we had listed several reasons to producing a green product greater that current non- WEEE product in view of us as below,
- Be a advantage for product promotion
- Market opportunity/ Competitive Advantage
- Personal experience of Need for the Product or Process
It was a selling point to our customer (product brand owner) that our product can help to improve their brand image to reduce an environmental impact.
Currently, some of the factory already applied WEEE directive to their electronic product. It become one of the considering point of customer when they select the vendors. A further variation on this theme was the view, expressed by representative of a number of companies, that not only would the companies' market share be increased in relation to their particular' green' product or process, but it may also be increased more generally because of the improved our corporate image resulting from greening.
Desire for a good corporate image is also an important motivating factor in the 'greening' of industry. Especially, we are going to promote to be an international level operation company.
Companies studied and personal experience of need for the product or process has been an important motivating factor in the further development of our products and production process.
Use an engineering approach to compare our current travel transformer model with competitor new model with several environmental impacts. And develop a new model by using the evaluation result.
In this project, this is categorized into below three objectives,
- Components mass breakdown analysis
- Compare the electronic efficiency between two models
- Compare the different between of two models in view of disassembly modeling.
- Consideration in view of recycling of e-waste of our product.
Compare the mass relation between massive percentage and no. of components for both models.
The purpose to find out the electronic efficiency performance of both model and proof which design is better in view of efficiency percentage.
Since both material recycling and component reuse require typically disassembly of components, design for disassembly is one of the key consider points when we label our product to WEEE directive.
The Literature review
Directive of WEEE
Scope and treatment target of WEEE
Directive prevention of WEEE is Waste Electrical and Electronic Equipment (WEEE), and in addition, the reuse, recycling and other forms of recovery of such waste so as to reduce the disposal of waste. It also aims to improve the environmental performance of all operators involved in the life cycle of electrical and electronic equipment, eg producers, distributors and consumers and in particular those operators directly involved in the treatment of waste electrical and electronic.
The producer must take responsibility for the end of product life
- Establish minimum collection targets
- Recovery / recycling targets
- would encourage design reuse or recycling and encourages the reduction of the dangerous impact loss
The directive covers ten categories list as below,
- Large household appliances
- Small household appliances
- IT and telecommunication equipment
- Consumer equipment
- Lighting equipment
- Electrical and electronic tools
- Toys, leisure and sports equipment
- Medical devices
- Monitoring and control instruments
- Automatic dispensers
WEEE directive (Website of WEEE registration: http://www.weeeregistration.com/)
Definition of WEEE
This definition includes electronic devices which are intended for reuse, resale, salvage, recycling or disposal. Others define re-usable (and repairable electronics) and secondary scrap (copper, steel, plastic, etc.) to be "commodities", and reserve the term "waste" for residue or material which has been represented as working or repairable but is dumped or disposed of or discarded by the purchaser rather than recycled including waste reuse and recycling. For purposes of this Directive, the following definitions apply:
- "electrical and electronic equipment" or "EEE" means equipment which is dependent on electric currents or electromagnetic fields to work properly and equipment for the production, transfer and measurement of such currents and fields falling under the categories listed in the Annex IA and designed for use with a voltage not exceeding 1000 volts AC and 1500 volts dc;
- "waste electrical and electronic equipment" or "WEEE" means electrical or electronic equipment is waste within the meaning of Article 1 (a) of Directive 75/442/EEC, including all components, subassemblies and consumables which are part of the product at the time of disposal;
- "preventive" measures to reduce the quantity and the harmfulness for the environment of WEEE and materials and substances contained therein;
- "reuse" means any operation by which WEEE or components thereof are used for the same purposes for which they were conceived, including the continued use of equipment or components thereof to collection points, distributors , recyclers or manufacturers;
- "recycling" means the reprocessing in a production process of waste to the original purpose or for other purposes, but the energy recovery which means excluding the use of combustible waste as a means of producing energy through direct incineration with or without other waste but with recovery of heat;
- "recovery" means any applicable operations provided for in Annex II B of Directive 75/442/EEC;
- "Disposal" means any applicable operations provided for in Annex II of Directive 75/442/EEC;
- "treatment" means any activity after the arrival of WEEE in a facility for depollution, dismantling, recovery or preparation for disposal and any other transaction for the recovery and / or disposal of WEEE ;
- "producer" means any person, regardless of the selling technique used, including by means of distance communication according to Directive 97/7/EC of the European Parliament and Council on May 20, 1997 consumer protection in respect of distance contracts:
- manufactures and sells electrical and electronic equipment under its own brand,
- resells under his own brand equipment produced by other suppliers, the retailer is not considered a "producer" if the brand of the producer appears on the equipment, except in accordance with paragraph (1), or
- equipment imports or exports electrical and electronic professional basis into a Member State. A person who exclusively provides financing under or pursuant to any finance agreement shall not be considered a "producer" unless he also acts as producer for the purpose of (1) to (3);
- "distributor" means any person who provides electrical or electronic equipment on a commercial basis to the party who will use them;
- "WEEE from private households" WEEE from private households and from commercial sources, industrial, institutional and others who, because of its nature and quantity, is similar to that of households;
- "dangerous substance or preparation" means any substance or preparation to be considered dangerous under Council Directive 67/548/EEC (2) or Directive 1999 / 45/EC of the European Parliament and Council (3).
Scope and treatment targets of WEEE Directive
There are some exceptions for certain product categories. In the context of the WEEE directive, reuse is defined as any operation which e-waste or components are used for the same purpose for which they are conceived after treatment. Recycling is defined as reprocessing in a production process of e-waste for the original purpose/ other purposes, excluding energy recovery.
In Figure 2.1.3a, it was showing the minimum targets of recovery and recycle by average weight of appliance.
Our product can be specifying as category 4. Consumer equipment, that means to meet the WEEE directive, we should recovery at least 75% by average weight of appliance.
Mass Breakdown analysis
The recovery of large components is crucial to the efficiency of selective disassembly. Even though the large components in a complex product are small in number, they nevertheless represent a substantial share of the product's mass.
A complex product has a few large components and numerous small once. Schuckert (1993) determined the mass distribution in a complex product with the help of a graph by ordering the components of a car according to their mass with the component number on X -axis, and the weight of components on Y-axis.
As can be from figure 2.2a, it is a logarithmic graph had showed the relation of weight of components and number of component. By using following subsection offers an aggregate approach that present more insight into the regularities of component mass distribution of different products.
Electronic efficiency evaluation
Efficiency is a function of a transformer's power losses, but it's easy to lose sight of what transformer efficiency. (Energy Fundamentals Handbook by Integrated Publishing, Inc.)
Components losses in transformers do not load (PNL) and the related loss (PLL). The drop, according to the load current, can be divided into I2R (PR) loss and stray loss. The losses are caused by parasitic eddy currents that produce electromagnetic interference flow in the windings, core, core clamps, magnetic shielding and other parts of the transformer. For high harmonic currents, the loss by eddy currents (PEC) in the windings is the component lost the most dominant.
Losses of transformer
Small power transformers are used when electrical components have a range of efficiency of about 80 ~ 90%, while wholesale distribution transformers may have efficiencies over 98 percent. Given the power loss in the transformer, the losses had few losses to combine different. One loss is mainly due to resistance in the conductors of the primary we have called this loss as a loss of copper or I2R loss. With the increase of current through the resistance of the driver, there is a voltage drop proportional to the increase of current flow.
Example: Initial applications of the electrical load of 10 amps. The resistance to the transformer winding conductor is 4 ohms. The voltage drop in the winding conductor is 4 volts.
E = I x R (2.3.1)
E = 10 amps x .4 ohms
E = 4 volts
If the electrical demand is increased and a current of 70 amperes is now required, the voltage drop across the winding conductor will increase.
E = I x R
E = 70 amps x .4 ohms
E = 28 volts
The resistance of copper increases with increasing current and temperature. This also affects the voltage drop. This lowers the secondary voltage charge is applied.
When current flows through a conductor, power is dissipated in the resistance of the conductive form of heat. The amount of power dissipated by the driver is directly proportional to the resistance of the wire and the square of the current through it. The higher the value of each current or resistance,
P = I x E
P = 70 amps x 28 volts
P = 1,960 watts
P = I2 x R
P = 702 amps x .4 ohms
P = 4,900 amps x .4 ohms
P = 1,960 watts
This is the power consumed of the conductor.
Another two losses is related to Eddy current and hysteresis in the core of the transformer unit.
When the input power and output power can be know, we can calculate the efficiency percentage of a transformer. The input power can equals to the product of the voltage applied to the current in the primary. And the voltage across the secondary is equal to output power. According above ideas, the difference between output and input power which is treat as a power loss. This percentage of efficiency of a transformer is calculated using the standard efficiency formula:
We can plot the efficiency graph as Figure 2.3.2 by using expression (2.3.2).
Back ground of product Design for disassembly
Disassembly (DFD) is a class of design methods and guidelines to improve the product disassemble for maintenance stop treatment easily. Many researchers have proposed guidelines for the general DFD disassembly process from a practical point of view.
DFD semi-destructive disassembly robot guidelines, removable or breakable parts are suitable for the preferred unit screws due to easy to disengage. Products embedded disassembly process, some of which a means of separation can be activated after the dissolution of the embedded product. For example, they developed the cathode ray tube (CRT) with a nickel-chromium alloy wire embedded along are required of separation, it can be induced by thermal stress cracks in the glass for the application of current. Although these works show the re-design to improve ease of use separate the individual joints, they do not address these issues to improve the overall demolition process involving multiple joints and components removed.
Disassembly process analysis (Hierarchical tree)
Several reports on disassembly processes in the literature are devoted to estimation of time and cost. In most of cases, a predefined disassembly sequence which is start with a hierarchical tree structure, the purpose is of this tree structure is similar as bill of materials. The hierarchical tree representation has a modular structure typically.
This implies that parallel disassembly is permitted, and at times may even be essential, in such a model which results in a divergent structure.
Connection diagrams and connection matrices
Connection diagram can show the topological relationships between the components/ parts of a final product. A connection diagram is an undirected graph in which represent components and the arcs represent connection.
In Figure 2.4.3, it was showing a simple assembly product with 4 full components as A, B, C and D and E. A, B, C and D are contained in container E. Screw G is connecting B via E, and screw F is connected A via E. A, B, C and D are fixed after two screwing. Thus, components G and F are fasteners both of them are discrete components.
In Figure.x.x Product process chain, the process after consumption is "repair". There have two different definition of repair, the first one is the repairing can done by consumer himself, others were done by producer/ repair consultant.
Here we will mainly discuses about the repairing by consumer. The simply example of consumer repairing is fuse; fuse is widely applied for household product such as coffee machine, coffee grinding, electronic burier. The purpose of fuse is used for avoid overload of product, it will break in advance if overload is applied. Then customer can only simply purchase a suitable fuse and ex-change the broken one.
After repairing the product life cycle can be extent again instead of changing of whole machine.
The disassemblies propose method is applied to two different models. The product selected for evaluation is the current selling travel transformer in Japan market.
This is a AC to AC step down transformer, it represent a AC power for converting the overseas standard 230v (Almost all of European countries and China use 220V standard) to an 110v outlet as some electric devices original brought from Japan ( Japan is using 110V). Japan customer will bring this transformer for working with their 110V electronic device when they travel to others country.
The final purpose is to find out the better design in those two type of travel transformer in view of design for environment.
Introduction of 2 models
From Figure 3.2.1, it had shown Model A is a transformer using Toroidal transformer techniques.
The weight of whole product without packing is 282g. It comes with a 60cm input cable with A type two socket plug. The rough size of Model A is L88mm* W59mm* W24.5mm. (127.2cm square)
The product specification of Model A as Input: 110~130V perform output 50VA(@110V) and Input: 220~240V perform output 35VA(@110V).
From Figure 3.2.1, it had shown Model B is a transformer using Laminated transformer technology. The weight of whole product without packing is 312.9g. It comes with a 30cm input cable with A type two socket plug. The rough size of Model B is L85mm* W48mm* W42mm. (171.4cm square)
The product specification of Model A as Input: 110~130V perform output 40VA(@110V) and Input: 220~230V perform output 20VA(@110V).
Electronic efficiency of two models
We sample 10pcs of models A which purchased from market.
For our current model B, we randomly selected 100pcs OQC data from 10 different shipments. Due to the limit resource, we not permit to purchase the sample QTY of model A and model B for comparison.
Because of the different sampling size, the evaluation may not represent accurately however it can be a reference in roughly.
Also we may consider the standard derivation and standard error to see the result and comment on the stabilize performance between model A and model B.
Electronic efficiency compute
Efficiency is a measure of a transformer's power on deliver the input power to the load.
Efficiency is expressed as a percent by (2.3.2) please see charter 2 for details:
The geometry of a standard transformer size limit we can do that size is proportional to the square root of the total power transformer. However, the nucleus familiar IE is not the only one that can be used. For example, using a toroidal, or donut-shaped core, it is possible to reduce the size and weight of a transformer of 20% to 50% over conventional cores with performance without sacrifice. This is possible because the losses in the core toroids are typically 10% to 20% of the total power loss, the rest being lost in the windings. This compares to a loss of heart totaling 50% of the total power loss for conventional processors. loss of heart below provide cooler operating temperatures and low magnetizing current. The toroidal transformer design uses the best of high permeability and low loss characteristics of a modern transformer core. Cores are commonly used for current transformers and instrument where low losses are extremely important. Other advantages are the higher operating temperature of lower efficiency, before the regulation, and less noise. The disadvantage is the low cost, although the improved production techniques are toroidal transformers more competitive prices.
Where Pout is the useful output power delivered to the load, and the pin is the power transformer. The difference between the pin and Pout is consumed by losses in the core and windings. The ideal magnetic circuit of the torus, and the ability to operate at higher flux density EI laminate, reduces the number of turns of wire needed and / or nucleus cross section. Either receive reduced losses. Toroidal transformers are typically 90 to 95 percent effective, while the EI laminate has a typical efficiency of less than 90 percent.
The inherent advantages of toroidal (ring, ring-shaped base) of the transformer, relative to other base configurations can generally be summarized as
- almost ideal magnetic circuit
- lower field stray magnetic,
- less volume and weight,
- less snoring, and
- greater efficiency.
We also compare for magnetic circuit between Toroidal transformer and Laminated transformer
In a structure of EI, it is difficult to align the grain structure of sheet metal stamped with the flow passage in the full path magnetic. This failure led to the loss of higher base and less efficient operation compared to toroids.
Product design for Disassembly at EOL of two models
Hierarchical tree structure
Under the Hierarchical tree structure, it was representation has a modular structure.
Above Hierarchical tree structure had applied for both model A and model B. The symbol of "S" in the diagram means refers to a subassembly.
Components connection relationship
For strongly connected unconstrained product, the maximum value of K is related to N as follow equation,
Kmax = N(N-1)
N= no. of components
This follows straight from the fact that each of N components is connected to (N-1) other components, which leads to N(N-1) connections. However, every connection is counted twice, thus the factor is .
To apply above equation to Model A, we get Kmax = (13)(13-1) = 78 (see figure 5.4.1a)
Subassembly and connection state values
The maximum number of different subassemblies SUB max is given by,
SUB max = 2n-1 = ?(N, K)
The maximum number of different connection can be obtained in a similar formula
CST max = 2k = ?(N, k)
The determination of the maximum nuber of subassembly states SSTmax = bN = ?(N,K) =? 1/k ? (-1)k
Materials selection/ recycle
Electronic scrape of Printed Circuit Boards (PCBs)
The printed circuit boards contain heavy metals such as antimony, gold, silver, chromium, zinc, lead, tin and Copper. According to some estimates, there is hardly any other product for which the sum of the environmental impacts for raw material, industrial refining and production, use and disposal is as extensive as for printed circuit boards. The methods of salvaging material from circuit boards are highly destructive and harmful as they involve heating and open burning for the extraction of metals. Even after such harmful methods are used, only a few of the materials are recovered.
Normally there have two different metal material Cu or Al we can use for toroidal transformer make. The values given in Fig. 5.X for primary Cu and Al are 1400 mpt/kg and 780 mpt/kg, respectively. As with cost, comparisons based on volume are more useful than comparisons on mass: per volume, the values can be expressed as 12.5 mpt/cm3 for Cu and 2.1 mpt/cm3 for Al. Even considering the 64% additional Al needed for equal dc resistance, the Al has under 30% of the environmental impact of the Cu winding by this measure.
While the copper and aluminium are widely recycled, and in both cases the value of ecological indicators point to much lower recycled metals, conductors use primary metals very often, due to the importance of high-purity conductors. However, designers can take some credit at the end of life recycling, if the products and components manufacturers design and demolition recycling program implemented. Lower environmental impacts of aluminium production, and low resistivity of copper seems to imply that the impact of trade-offs and related materials between production and related impacts and energy production, but that is not the case. Even with enough of aluminium, so the loss is the same as the material of aluminum is a multi-factor and three low. However, for any given command, there is a balance of energy and material. People can choose the number of conductors used to optimize the transaction, or to optimize the trade-off costs of materials and energy costs. One such optimization results are shown in Table 3. It is worth noting that the best choice based on the total cost of the current density is very similar to the best current density chosen based on the environment. Copper, aluminium, have a high environmental impact of electricity.
WEEE standard of selected product (transformer)
The product had selected for experiment is court as category 4. Consumer Equipment ( see Figure 4.1.3a), that means we have to meet the minimum targets of recovery percentage (%) not least than 75% or Recycle & Reuse percentage (%)not least than 65%.