Gina Sjöberg Royal Institute of Technology
Kristina Nilsson Bromander MJ145X
Bachelor of Engineering Thesis, VT 2014 Supervisor: Thomas Nordgreen
Quality Function Deployment of FirePipe
-the foldable cooking stove
Abstract
Each year, millions of people flee their homes due to political conflicts, fearing the risk of being persecuted. As well, mounting environmental issues engenders an increasing stream of people-displacement. Humanitarian organisations have for decades acted in order to help people of concern in refugee situations. For them, it is vital to be able to provide quick relief and must therefore be mobilized via suppliers and distribution channels with needed goods for humanitarian care in case of an emergency.
Gustav Innovation in collaboration with the Royal Institute of Technology in Stockholm (KTH) and the authors of this document, is developing a field cooking stove called FirePipe which is both quick and easy to distribute, as well as sustainable financially, environmentally and humanitarily in provisional settlesments.
The following document treats the development of a Quality Function Deployment (QFD) evaluating the most important characteristics of such a stove in order to create an as succesful product as possible. It also contains a competitive analysis to illuminate FirePipe’s strengths and weaknessess in relation to similar products.
According to the QFD analysis the most important Quality Characteristic to focus on in future engineering work is the reduction of the fuel mass consumption of FirePipe. Other important paramterers are the ability to save time using FirePipe as well as reducing harmful emissions.
If the target values for these features can be met, FirePipe will be a qualitatively consistent alternative to the existing market that particularly will deliver great opportunities for easy cost-effective logistics.
Sammanfattning
Varje år flyr miljontals människor sina hem på grund av politisk oro, med rädsla för förföljelse. Samtidigt med ökande miljöproblem, ökar risken att naturkatastrofer kommer tvinga människor på flykt. Hjälporganisationer har länge arbetat för att hjälpa människor i sådana kritiska situationer, exempelvis i flyktingläger. För dem är det viktigt att snabbt kunna mobilisera och erbjuda hjälp i nödlägen med hjälp av leverantörer och distributionskanaler för de saker som behövs vid humanitär omvårdnad.
Gustav Innovation utvecklar i samarbete med Kungliga Tekniska Högskolan (KTH) och författarna till denna rapport, fältspisen FirePipe som är både snabb och lätt att distribuera, likväl hållbar ekonomiskt, miljömässigt och humanitärt i provisoriska bosättningar.
Följande rapport behandlar genomförandet av en kundcentrerad kvalitetsutveckling, en så kallad Quality Function Deployment (QFD), I denna undersöks och utvärderas de viktigaste egenskaperna för en sådan spis som ett steg i att kunna utveckla en så framgångsrik produkt som möjligt. QFD innehåller även en konkurrentjämförelse som belyser FirePipe’s styrkor och svagheter jämfört med liknande produkter.
QFD resultatet visar att den viktigaste tekniska delen av FirePipe, vilken därmed är det som framtida arbete bör fokusera på, är att minimera dess bränsleanvändning. Andra viktiga aspekter är möjligheten att spara tid genom att använda FirePipe samt minskningen av skadliga utsläpp. Om målvärdena för dessa funktioner kan uppfyllas kommer FirePipe att erbjuda ett kvalitetsmässigt stabilt alternativ till den existerande marknaden som framför allt ger stora möjligheter för en enkel och kostnadseffektiv logistik.
Nomenclature
Acronym Full form
C2ES Center for Climate and Energy Solutions
CO Carbon Monoxide
CO2 Carbon Dioxide
CRIC UNHCR’s Core Relief Items Catalogue
EPA United States Environmental Protection Agency
FAR Fuel Air Ratio
GACC Global Alliance for Clean Cookstoves
ICS Improved Cook Stoves
IHME Institute for Health Metrics and Evaluation
KTH Kungliga Tekniska Högskolan
(The Royal Institute of Technology)
NASA National Aeronautics and Space Administration NBER National Bureau of Economic Research NCAR National Center for Atmospheric Research
QFD Quality Function Deployment
PM Particulate Matter
PPMV Parts Per Million Volume
SST Standard Safety Test
TSF Three Stone Fire
UCAR University Corporation for Atmospheric Research
UN United Nations
UNHCR United Nations High Commissioner for Refugees
USP Unique Selling Point
WBT Water Boiling Test
WHO World Health Organization
Table of Contents
Abstract ... 2
Sammanfattning ... 3
Nomenclature ... 4
1. Introduction ... 1
2. Background ... 2
2.1 UNHCR – background, mission & strategy ... 2
2.2 UNHCR & FirePipe ... 3
2.3 Refugee Camps Today ... 3
3. Environmental and Health Issues ... 4
3.1 Biomass cook stoves ... 4
4. Combustion ... 5
4.1 Basic combustion ... 6
4.2 Biomass & secondary combustion ... 6
5. Methodology ... 8
5.1 Quality Function Deployment ... 8
6. Market Evaluation ... 14
6.1 Improved Cook Stoves ... 15
6.2 Test Results of Cook Stove Performance ... 15
6.3 Three Stone Fire ... 18
6.4 Rocket stove ... 19
6.5 One-pot mud stove ... 21
6.6 Ghana Wood ... 22
6.7 VITA stove ... 23
6.8 Save80 ... 24
6.9 Ten design principles ... 24
7. QFD Evaluation ... 25
8. Result and Discussion ... 30
9. Conclusion ... 3
References ... 4
Appendix A: QFD for FirePipe ... 8
Appendix B: QFD results for FirePipe ... 9
Table of Figures
Figure 1. Secondary Combustion Stove (Johnels & Murray, 2013) ... 8
Figure 2. QFD Template ... 9
Figure 3. Demanded Qualities (1) and Weight (2) ... 10
Figure 4. Quality Characteristics (3) and Minimize/Maximize fields (4) ... 11
Figure 5. Correlation Matrix (5) ... 12
Figure 6. Relationship matrix (6) and target value field (7) ... 13
Figure 7. Competitive Analysis field (8) ... 13
Figure 8. Relative weight field (9) ... 14
Figure 9. Result template from Aprovechos studies (EPA, 2011a) ... 17
Figure 10. A traditional three stone fire (Grassroots Engineering) ... 18
Figure 11. Results for the three stone fire, (EPA, 2011a) ... 19
Figure 12. Rocket Stove (NokuBunva, 2012) ... 19
Figure 13. Test results for the rocket stove (EPA, 2011a) ... 20
Figure 14. One-pot mud stove (MRHP, 2014) ... 21
Figure 15. Test results for the one-pot mud stove (EPA, 2011a) ... 21
Figure 16. Ghana wood (Toloya Energy, 2006) ... 22
Figure 17. Test results for Ghana Wood (EPA, 2011a) ... 22
Figure 18. VITA stove (EPA, 2011a) ... 23
Figure 19. Test results for the VITA stove (EPA, 2011a) ... 23
Figure 20. Relative weight [%] for the Quality Characteristics. The four most important are marked with red stacks ... 31
1 1. Introduction
Since clean water is essential for humanity, the ability to boil water to get rid of bacteria is vital to people that do not have access to clean water. So is the ability to prepare food in a way that makes it safe to eat. Many people living in disaster areas do not have access to any other cooking facilities other than over open fire, which is both inefficient and dangerous since the smoke increases risks for a number health issues, for example lung cancer (Johenls & Murray, 2013).
Gustav Innovation is a small company based in Stockholm working in the design and product realization field. As this is being written, Gustav Innovation is developing a product, FirePipe;
a foldable cookstove, which quickly and easily can be sent to areas in need of help to a low cost. The basic idea of the Unique Selling Point (USP) of FirePipe is for it to be shipped as a flat sheet of metal, which is folded into a stove. The compact design makes it possible to store a considerable amount of units in small volumes. A couple of different designs of the product have been developed, some using primary combustion and others using secondary
combustion. Studies have been done on the performance of FirePipe and the conducted tests detected some areas of improvement. For example tests showed that in the existing models, the one using primary combustion provided a higher effect (Johenls & Murray, 2013).
Notwithstanding, secondary combustion is preferable in the sense it produces less smoke.
The problem statement of the project is to evaluate the different product characteristics to find out which of them being most important, and therefore needs to be prioritized in the
development of FirePipe for the product to be as successful as possible.
Accordingly, the aim of this work is to develop a quality function deployment (QFD) chart, a so-called house of quality (Ullman, 2010) for FirePipe. In order to do so the development of this chart will state the methodology. This will define and present the, by the customer, demanded qualities and accordingly the technical quality characteristics meeting these
demands. This will contribute to the choice of approach and further development of FirePipe.
By combining a solution, which is environmentally, financially, and humanitarian more sustainable, the aim of launching FirePipe is to increase living standards and health among people living under extreme conditions. As well, minimizing emissions of harmful fumes, particles etc. aims to decrease the impact on climate change and therefore contribute with an environmentally sustainable solution.
In order to come to a conclusion, the starting-point of this report will be to introducing information about the problematic factors in the implementation of a product like FirePipe.
The previous work done will provide knowledge about the early stages of the FirePipe project, which is concluded in several reports done by students at the Royal Institute of Technology (KTH). Similar stoves on the market will be evaluated to gain information on how to address and solve the emerging problems. Linking basic combustion physics to the
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design possibilities of the stove, the understanding of efficiency increase and emissions will be fortified.
The acquired information will underpin the choices of focus points, which will be treated in the QFD. The chart will give the FirePipe project clear and consistent guidelines about the needed technical specifications in the fields in need of improvement before FirePipe can be launched. The basic idea of FirePipe is for it to be a product that is cheap and easy to
distribute. These are examples of factors, which the QFD will entail. Also safety factors, both physical and environmental, will be considered.
To sum up, the goal of this project is to deliver a QFD with well-researched and accurate quality characteristics, which will help Gustav Innovation in their process to launch FirePipe.
2. Background
This section serves as an introduction of the field of work done by organisations with possible interest in FirePipe. The information will provide further understanding the different
perspectives of the potential customers.
2.1 UNHCR – background, mission & strategy
In the backwash of World War II in 1949, the United Nations General Assembly decided to form a sub organisation in order to protect the refugees forced to flee due to conflicts or catastrophes. Originally, the idea of the organisation was for it to work on a three-year mandate, but the need for the kind of work provided was soon to be confirmed by numerous arising conflicts (UNHCR, 2014d). The organisation now works continuously “until the refugee problem is solved” (UN, 2013). Today, the organisation has around 8,000 staff members working in 126 countries. (UN, 2013)
The fundamental mission of the United Nations High Commissioner for Refugees (UNHCR) is to be an impartial organisation helping “to lead and coordinate international action for the worldwide protection of refugees and the resolution of refugee problems” (UNHCR, 2012b).
This statement is applied through several fields of work.
One of them is to provide humanitarian assistance for people who have been uprooted from their own country and state. This involves pursuing the rights of the refugees and making sure the countries holding the refugees act on these principles (UNHCR, 2014c). UNHCR provides refugee registration & counselling to the possible extent for people of their concern. The final goal of the organisation is of course to find long-term solutions for people to live in. Different options can include resettlement in another country; advice in an asylum application process and integration issues. If the displaced person has the possibility of repatriation, i.e. to return to his/hers country of origin, UNHCR can provide administrative help as well as logistical help such as transport etc. An inter-stage between flight and long-term settlement will be discussed further in section 2.3.
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An important constituent in UNHCR’s work is emergency assistance. This includes provision of the basics for human survival; clean water, medical care, blankets, household goods and sometimes foods. To be prepared for blazing emergency situations, a pre-arranged net of suppliers of the needed goods as well as shipping companies is composed. The organisation’s benchmark is to be able to have the means to send out goods enough to help half a million people in need whenever.
When people are forced to flee, few possessions are brought with. Although UNHCR can provide some relief; people are to rely on the environment to provide for their needs, e.g.
cutting down trees to build shelters, collecting food and firewood from the surroundings.
Knowing this, UNHCR claims to take environmental impacts of displacement into consideration in their work in refugee situations (UNHCR, 2014b). By doing so, a contribution is made to a sustainable development of the work of UNHCR.
To be able to fund its activities, the vast majority of UNHCR’s funding comes from voluntary donors. These mainly come from non-governmental organisations (NGO, corporations, trusts, foundations and individual citizens). A minute part of the budget comes from the UN
(UNHCR, 2014a)
2.2 UNHCR & FirePipe
In order for UNHCR to be able to provide emergency assistance, a number of products have been selected after evaluation as a part of their “Core Relief Catalogue”. For a product to take place in this catalogue it must have a clearly proven advantage, technically as well as
knowledgably about the conditions in which it will be used. Tents, mosquito nets, blankets are all examples of this. The majority of these resources are stored on standby in stockrooms located primarily in Copenhagen and Dubai (UNHCR, 2012a).
As mentioned earlier, possible customer for FirePipe could be UNHCR. The objective of this report is therefore to see how the creation of a product as applicable as possible to the their product specifications would be focused, meeting both the requirements of their staff as well as the end-users linked to the i.e. people in refugee camps.
UNHCR has the policy on offering an as wide a base of businesses as possible, the
opportunity to participate in the selection of the CRIC product (UNHCR, 2004) To be able to compete with related products, it is vital to know characteristics of the opponents in order to stand out among them. This being said, the competitors will be investigated further in section 6.
2.3 Refugee Camps Today
There are about 10.5 million refugees across the world today (UNHCR, 2012d). With on- going political conflicts around the globe for example in the Middle East and Africa; around
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23,000 people leave their homes each day in the search of a more decent existence (UNHCR, 2012d).
As well, with increasing effects due to global warming, it is possible to predict new causes for people needing to seek refuge elsewhere (UNU-EHS, 2005). Taking all different causes for displacement into account, approximately 45 million people are forcibly relocated from their homes (UNHCR, 2012d).
The vast majority of the people classified as refugees are living in so-called refugee camps of varying size and convenience. Most of these camps are located in developing countries, such as Pakistan, Kenya or Ethiopia (UNCHR, 2012d).
The formation of a refugee camp is not with the intention for it to be a permanent solution for the living situation for the people fleeing. The purpose of an establishment of a refugee camp is to form a temporary site to meet the basic human needs, such as nutrition, medical care and shelter, for the people escaping (Nationalencyklopedin flyktingläger 2014)
Despite it is not intended for refugee camps to be a durable solution; some camps like the Dadaab camps in Kenya in have existed for over twenty years (UNHCR, 2012d). These camps are now becoming the home to a third generation of refugees, which means people are living their entire lives in the camps. Because the camps are not only temporary, the reality upholds needs for as well more durable solutions in these camps. An example is the problem with deforestation linked to the building of refugee camps; building of shelters, the gathering of fuel for cooking, light etc (Johenls & Murray, 2013).
3. Environmental and Health Issues
The biomass cookstove has an impact on the climate change at both regional and global levels. The following section assesses the present situation and the problems it comprises.
3.1 Biomass cook stoves
In the atmosphere, carbon fully oxidized as carbon dioxide, fully reduced as methane, and in particulate form as black carbon soot causes the greenhouse effect making the earth habitable.
However the greenhouse effect is getting stronger as an unnatural amount of greenhouse gases is added to the atmosphere because of human activities. This partly derives from biomass cookstoves, which emissions are added to the atmosphere and accordingly is warming the climate of our planet (UCAR/NCAR, 2014a).
When burning biomass fuel, a vast amount of pollutants are released, for example emissions of carbon dioxide (CO2). About 730 million tons of biomass is burned in developing countries each year, amounting for more than one billion tons of CO2 emitted into the atmosphere (The World Bank, 2011). This makes CO2 the primary greenhouse gas emitted through human activities (EPA 2011b). CO2 absorbs heat energy released from the earth and thereby the molecule goes into an excited unstable state. It stabilizing itself again by releasing the energy
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absorbed, only now some of the released energy will go back to the earth contributing to the global warming (McCormick, John L, 2006).
The amount of CO2 in our atmosphere is rapidly increasing. In the mid-19th Century, before the Industrial revolution, there were about 270 parts per million volume (ppmv) ofCO2 in the atmosphere compared to 400 ppmv (UCAR/NCAR, 2014b). CO2 has a long atmospheric lifetime and it will take decades for the concentrations of CO2 to begin to stabilize after emission reductions (C2ES, 2010).
In addition to CO2, the incomplete combustion of biomass, which will be discussed further in section 4.2, produces particulate matter (PM) emissions. One of the components of the PM emitted is black carbon (BC) which also is a great contributor to the global climate change (EPA, 2011b). More than two-thirds of the global BC emissions come from open biomass burning and residential sources (EPA, 2010).
The BC particles in the air absorb sunlight, which generates heat in the atmosphere. When deposited on snow and ice it heats both the air above and the snow and ice below causing accelerating melting (Kaspari.S et al, 2013). Since ice and snow reflects sunlight the
accelerating melting decreases this reflection and therefore this contributes to the heating of our atmosphere even further.BC contributes the equivalent of 25 to 50 percent of carbon dioxides contribution to the global warming (GACC, 2014b). BC only remains in the
atmosphere for a few weeks, compared to CO2 who remains several decades, why minimizing BC emissions give more immediate results (C2ES, 2010). Therefore it is of great importance to improve cookstoves that is one of the greatest contributors to BC emissions.
The smoke from the incomplete combustion of wood, which is the most common fuel in refugee camps, contains at least 26 harmful air pollutants, e.g. dangerous particulate matter (PM) and carbon monoxide (CO) (Just et al, 2013). This is a severe danger to the people cooking with traditional stoves and over open fire and causes about four million deaths annually, which make it the fourth biggest risk factor for disease in developing countries. In addition, over ten millions of people become ill due to it (IHME, 2010). Only among children under the age of 5 there are one million deaths due to pneumonia caused by indoor pollution from stoves. With cleaner and more energy-efficient stoves a lot of these deaths can be avoided (WHO 2011b). There are also other health aspects that make it important to reduce amount of fuel needed, such as the risk for injury when being forced to collect firewood for hours daily. Especially women are exposed, with the risk of being attacked and/or sexually assaulted (Johnels & Murray, 2013.)
4. Combustion
In the innovation process and development of a new kind of cookstove, it is important to understand the basic science of combustion. By doing so, the technical application is better substantiated and the certain product has a higher possibility of being as efficient as possible.
Different mechanisms of combustion will hereafter be briefly explained.
6 4.1 Basic combustion
To be able to extract the internally stored energy from a material, one way of doing so is a process called combustion. During combustion a fuel chemically reacts with a source of oxygen, which creates heat and new chemical substances called exhaust. To be able to start the combustion reaction, a source of heat is needed, e.g. a lit match or such like (NASA, 2008).
By controlling the oxygen supply in the combustion process, it is possible to control the heat generation as well as the emitted exhaust. When there is a sufficient air supply during the process, a so-called complete combustion takes place. The reciprocal equivalent amount between the reagents in order for them to completely combust is described as the
stoichiometric ratio.
Burning a gas derived from biomass, the chemical reactions involve the oxidisation of carbon to form carbon dioxide, CO2, and hydrogen, H2, to form water (Demirbas, 2007).
Equation (1) below shows an example of this, using the simplest form of hydrocarbon methane (CH4) as fuel.
CH4 + 202 → CO2 + 2H2O (1)
However, in a case where the fuel/air ratio (FAR) is higher than the stoichiometric ratio, the mixture of reagents is fuel-rich. This means the supply of oxygen is not satisfactory and the combustion will therefore be incomplete.
An incomplete combustion means a formation of different combustion products compared to the ones in the complete reaction. In the oxygen deficient case, the yields produced are different volatiles as well as PMs. One of the volatiles produced is carbon monoxide, CO, which unlike carbon dioxide is a flammable gas (Nationalencyklopedin, koldioxid 2014).
Equation (2) shows the chemical equation when methane burns in an oxygen-deficient ambience.
2CH4 + 3O2 → 2C0 + 4H2O (2)
The yields produced vary due to a number of factors such as which fuel is used, the
temperature and amount of moisture present in the material (Demirbas, 2007). As well, the slower and the better mixed the fuel is, lesser carbon monoxide is produced (EPA, 2011a).
4.2 Biomass & secondary combustion
In the majority of the world and particularly in developing countries, the most accessible and used fuel is biomass (EPA, 2011a). Biomass is all kinds of biological materials, such as wood, dung and crop residues, which can be used to extract energy from (Nationalencyklopedin, biomassa 2013). The materials mentioned can also be compressed into more energy-dense
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units of fuels in the form of e.g. pellets (Nationalencyklopedin, pellets 2014). The burning of a solid biomass is somewhat more complex than the combustion of a gas, described in the previous section. When heating a biomass by burning, firstly the moisture the fuel inevitably contains, starts to evaporate towards the surface and subsequently is driven off (Department of the Environment and Heritage, 2005). As the biomass is being burned it releases volatiles, which arise from the surface with the hot air. The pieces of fuel themselves burn on the surface due to the high temperature. While doing so, the fuel falls apart due to carbonisation.
This is mutual for the burning of biomass in all types of circumstances and different cookstoves. The air enabling the reaction is called the primary air.
However, earlier in the innovation process of FirePipe, the application of secondary air in the combustion process has been considered (Johnels & Murray, 2013). This mechanism can be achieved by igniting the unburnt gases, such as carbon monoxide, and PMs rising from the primary combustion locality. These gasers are marked with a red arrow in Figure 1. They are still reactive because of the high fuel-air ratio in the primary combustion locality. To achieve complete combustion and a stoichiometric relationship between the fuel and air, more air is introduced into the system.
The blue arrows in Figure 1 represent the added extra air, which first needs to be superheated in someway, in order to avoid cooling down the fuel and constraining the ignition. A possible way of doing so is to let the extra air travel through a separate interstice between the
combustion chamber and the outer cylinder of the stove. In Figure 1 heat is represented with orange arrows. Higher up in the vessel, the superheated air is introduced via holes in the walls of the inner tube. This is indicated with green arrows in Figure 1. There it is mixed with the rising unburnt volatiles which are oxidised.
By adding the secondary air, the PMs produced in the primary combustion locality, are as well burnt if the temperature is sufficiently high. This creates an almost smokeless fire (Turns, 1996)
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Figure 1. Secondary Combustion Stove (Johnels & Murray, 2013). Blue arrows represent new air, orange heat flow, red PMs and green superheated air.
5. Methodology
The following section is a description on how the work of the development of the QFD will be conducted. It describes the QFD model, which forms the basis of the analysis of FirePipe in section 7.
5.1 Quality Function Deployment
The realisation of a product means operating over multiple interdisciplinary fields. Enabling to communicate the various aspects of an innovation process and seeing the linkage between marketing and engineering, the QFD method saves money, time and effort. The usage of a project mapping method called “the House of Quality”, gives a clear translation of subjective customer desires into objective engineering criteria. The different fields of work are shown in a schematic figure found in Figure 2. A total QFD consists of the different fields:
1. Demanded Qualities 2. Weigthings
3. Quality Characteristics 4. Target Values
5. A Correlation Matrix 6. A relationship matrix 7. A competiton analysis 8. A relative weight result
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The sequent section describes the different fields and the step-by-step method more thoroughly (Clausing & Hauser, 1988).
Figure 2. QFD Template
10 Demanded Quality & Weighting
The first step in the QFD methodology is to identify the intended customers, both external and internal. Taking this perspective into
account is vital in order to make the product attractive from a market point-of-view. External customers are the end-users of the product who have their view of what is the best product.
Internal customers on the other hand are people within the company, which interests most often lie in optimising the simplicity and workability in the realisation of the product. It also includes people working with sales, transportation or reparations etc. Internal demands can also comprise the following of rules and regulations, for example safety standards regarding a certain type of product. Once the customers have been identified, their requirements for an appealing product are ascertained. There are different methods for how this information can be
obtained. These can involve surveys, interviews, workshops and studying statistical data.
However, after the key demands have been recognised, they are listed in the “Demanded Quality”-field marked with “1” as shown in figure 3.
These Demanded Qualities are expressed in a way focusing on what the product must be able to do, not presenting a possible technical solution to the demand. To clarify the overview of the customer desires, the demands are sub-divided into bundles regarding their area of impact.
Every quality must also be weighted in correlation with its importance according to the expressed desires of the customers. Each Demanded Quality is given a weighting figure from 1-5, where 1 means “Not so important” and 5 is “Very important”. The weighting figure is noted in the field marked with “2” in figure 3.
Figure 3. Demanded Qualities (1) and Weighting (2)
11 Quality Characteristics & Target Values
Once the Demanded Qualities have been mapped, the next step in the QFD method is to interconnect them with technical specifications for the product. While the demanded qualities are the “Whats” of the product development analysis, this step represents the determination of the “Hows” i.e. how the Demanded Qualities can be achieved.
These objectives are referred to as Quality Characteristics, which represent clear, concrete and most important quantitatively measurable values for the product characteristics. They are listed vertically in field 3 shown in figure 4. Each Demanded Quality should be first of all linked to one Quality Characteristic, making sure all demands are to be taken care of in future engineering work. Each Quality Characteristic should also be described with and associated arrow pointing up ( ) or down ( ), noted in field 4, which clarifies the aim to minimize or maximize a specific feature.
The Target Value of the Quality Characteristic is defined in a physical magnitude and is also listed in the QFD chart, which is presented in field 7 in figure 6. The values should be decided from market surveys and/or competitive analysis. Reaching these values is the goal of the engineering product work to be conducted.
Figure 4. Quality Characteristics (3) and Minimize/Maximize fields (4)
12 Correlation matrix
A change of one Quality Characteristic might connote another is also affected. For example, the increase of heat transfer to the ambience negatively affects the thermal efficiency of a stove since the energy is dissipated. These interconnections can be mapped by using the so-called Correlation Matrix in the QFD chart. Each Quality Characteristic is given a connection with all the other through the “roof” of the House of Quality, which can be seen in figure 5. As the different features can involve both positive and negative relations, the way in which they are, is subdivided into four categories: high positive (represented by the symbol ++), positive (+), negative (-) or high negative correlation. ( ) If there is no correlation the field where the Quality Characteristic are linked should be left open.
Figure 5. Correlation Matrix (5)
Relationship matrix
With the goal to create a product meeting the demands of the customer, it is important to understand the linking between the requirements and the technical specifications of the product. The relationship matrix gives the connection between these two. The relationship is divided into three possible categories with an associated weighting number of 1
(represented with the symbol ), 3 (O) or 9 (θ) depending on if the two are weakly, moderately or strongly connected. Field 6 in Figure 7 contains examples on the relationship between two Demanded Qualities and their associated Quality Characteristics.
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Figure 6. Relationship matrix (6) and target value field (7)
Competition
To be able to compete with and outdo existing products, the QFD method entails a competition analysis. By doing so, it is possible to see if the project has a chance of doing well in comparison to the existing market. If the competition analysis shows one’s product is inferior in a number of Demanded Qualities, the project should not be followed through.
As shown in figure 7, on the opposite side from the Demanded Qualities the own product is compared to its
competitors. Each product is given a rating from 1-5, where 1 is the worst and 5 the best, according to their
performance in the different fields of customer interest. The rating should preferably be based on customer
inquiries equivalent to the ones forming
Figure 7. Competitive Analysis field (8)
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the Demanded Qualities list. If this is not possible, a team-based evaluation can be done although it might risk the objectiveness of the comparison and therefore be less useful.
The values used for the own product can be based on conducted tests, or if this is not available based on the target values for the Quality Characteristics. The competitive mapping does not relate mathematically to the rest of the QFD, but gives an indication on how the product will do on the market.
Relative Weight
The end result of a QFD is the Relative Weight number. This number is a percentage presenting how important it is to reach one Quality Characteristic’s target value in relationship to the others. This is represented in the red field 9 in Figure 8.
This gives guidance on which technical properties to focus on in order to achieve the best outcome owing to the weighting number for the different customer demands. Some will receive a low weighting number and the conclusion must then be made that some
characteristics, which seemed important in the forming of the Demanded Qualities, must be neglected. The explanation lies within the relationship matrix and the connection between the other characteristics, which have been recognised as more prominent. With this in mind, if the product already possesses an advantage in some area compared to competing products, it is important to maintain this edge while enhancing the others.
Therefore the relationship matrix must be continuously considered throughout the
development work. Finally, the product will hopefully meet the technical requirements of the customers as well as possible.
Figure 8. Relative weight field (9)
6. Market Evaluation
To gain information about what values are reasonable to use as target values for FirePipe an analysis of similar stoves available has been made. Also included are clarifications of expressions and concepts, which are used in the QFD analysis of FirePipe (Ullman, D.G., 2010).
15 6.1 Improved Cook Stoves
A number of improved cookstoves (ICS) have been developed, which are more efficient and less damaging for health and environment compared to an open fire. There are a lot of different types of ICS available on the market with different designs and technologies. Some of them are easy and cheap to manufacture while others are more expensive with more complex design and technique. The size of the stoves also differs since some are made to be stationary while others are designed to be easy to transport.
The basic idea of FirePipe is for it to be easy but first and foremost cheap to manufacture. It also has to be easy to transport in a large amount so that it can reach the people in need in an easy way. Therefore this market evaluation has been limited to the stoves that could meet these requirements and therefore are competitors to FirePipe.
In order to evaluate and be able to compare these stoves as accurately as possible, tests on the various models made in identical manner are needed. Why this is important is because feeding wood to the fire in different ways and using different type of wood give different results.
Since this project does not entail experimental parts, a study called “Test Results of Cook Stove Performance”, done by Aprovecho Research Center for the United States
Environmental Protection Agency is used to provide this information.
6.2 Test Results of Cook Stove Performance
The study was developed by Aprovecho Research Center to provide technical support data to household energy and health projects. Tests were performed on 18 stoves in three ways;
1. Water Boiling Test.
The Water Boiling Test (WBT) is a standardized test for measuring how efficiently a stove uses fuel to heat water. The test can also be used for benchmarking with other stoves. The WBT gives information on the stove’s thermal efficiency, fuel consumption, burning rate, fuel and time use as well as the turn-down ratio (i.e. how much the user adjusted the heat between the low and high power phases). The stoves are measured in three phases;
• Phase 1: High Power (cold start)
• Phase 2: High Power (hot start)
• Phase 3: Low Power (simmering)
The tests should be performed in a, for the geographical area in which the test is performed, standard shaped lidless pot with a volume of about seven liters. The high power phases are conducted by bringing five liters of water to a boil, from a cold start (when the stove is at room-temperature) respectively from a hot start (directly after the cold-start test is finished, while the stove is still hot). This is done to simulate the stoves capacity in warmer climates or for example when the stove is used to cook multiple things in a sequence.
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Once the water has boiled, data is collected on how much time elapsed to bring water to boil, how much water is left in the pot and the amount of fuel and char remaining,
The low power phase test means making the same measurements as mentioned above after 45 minutes of simmering, keeping the temperature around 3°C below the boiling point
(Aprovecho Research Center, 2013). In Appravecho’s test, the WBT protocols from
University of California Berkeley (UCB) have been used; saying three repetitions per stove should be done to get an accurate result (UCB, 2004)
2. Three additional WBT were made under a emission hood measuring the level of carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM) and hydrocarbons.
3. The stoves were also tested with three WBT in a 15 m3 test kitchen with three air exchanges per hour where the levels of CO, CO2 and PM were measured again.
In addition to the WBT a Standard Safety Test (SST) were also performed. The SST refers to method for evaluating stoves safety that takes many aspects into account. The following criteria are rated as excellent (four points), good (three points), fair (two points) or poor (one point) for safety evaluation;
• Sharp Edges/Points
• Cookstove Tipping
• Containment of Combustion
• Expulsion of Fuel
• Obstructions Near Cooking Surface
• Surface Temperature
• Heat Transfer to Surroundings
• Cookstove Handle Temperature
• Flames/Heat Surrounding Cookpot
• Flames/Heat Exiting Fuel Chamber
An overall cookstove safety rating is determined where a stove can receive a maximum of 40 points and a minimum of 10 points. A score over 31 is ranked as good. (Johnson, N, 2006)
The result of these tests is presented according to a result template shown in figure 9. This template is hereafter used to present the test results for all the tested stoves. Five of these stoves have been identified as FirePipe’s competitors, based on their affordability, type of fuel usage and size. They will therefore be presented further in the following sections 6.3-6.7.
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Figure 9. Result template from Aprovechos studies (EPA, 2011a)
18 6.3 Three Stone Fire
The most commonly used stove in developing countries is the Three Stone Fire (TSF) shown in Figure 10. It is a traditional biomass stove, which is merely three stones of equal height placed next to each other to serve as a base for a skillet over an open fire.
The combination of this inefficient stove design and the use of solid fuel, leads to incomplete combustion and high levels of air pollution emissions damaging both health and climate. Even though it is energy inefficient and associated with enormous health risks, there are still almost three billion people all over the world obtaining their household energy using these traditional stoves (WHO 2011a).
The efficiency of the TSF depends a lot on the operator and the conditions of use. If the wood is fed into the fire in a way making the sticks burn at the tips, and continuously pushed into the center as the wood is being consumed, the fire becomes hot and burns relatively cleanly. If the sticks start to smolder, a lot of smoke will be made. A well-constructed TSF, which is protected from wind and that is fed dry wood in a controlled way to optimize its performance can have a thermal efficiency between 20% and 30%. A fire made with moist wood and less observance to the wind can have as low as 5% thermal efficiency (EPA, 2011a).
In Figure 11 the results for the TSF from Aprovechos studies are presented.
Figure 10. A traditional three stone fire (Grassroots Engineering)
19 6.4 Rocket stove
The rocket stove, shown in figure 12, is constructed with a combustion chamber in the form of an L. It has a vertical chimney about two times as long as the horizontal wood/air intake, which allows partial combustion of gases and smoke inside the stove and increases the amount of complete combustion and cleaner emissions. Wood is fed at the horizontal opening of the stove on a fuel shelf, making it possible for air flow below the fuel, contributing to effective combustion (GACC 2014a). The rocket stove follows the ten design principles that were described by Dr.
Larry Winiarski in 1982 to improve heat transfer efficiency (Winiarski, L, 2005). These principles are explained in section 6.9.
Figure 11. Results for the three stone fire, (EPA, 2011a)
Figure 12. Rocket Stove (NokuBunva, 2012)
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A rocket stove can be built using material available such as tin cans for combustion chambers and ash for insulation. This making it a cheap, yet more effective and clean alternative
compared to the TSF.
A well-constructed rocket stove will, according to the results from Aprovechos studies shown in Figure 13, both reduce harmful pollutions considerably and improve heat transfer and combustion efficiency leading to a reduction of fuel use and emissions (EPA, 2011a).
Figure 13. Test results for the rocket stove (EPA, 2011a)
21 6.5 One-pot mud stove
One-pot mud stoves, as the one shown in figure 14, have been made and used in Africa for decades. It is made by using earthen mixture of 60 % sand and 40
% clay. Sawdust is added to improve insulation and to make the stove more lightweight. The sawdust near the inside of the wall burns away, creating pockets of air helping further with isolation of the fire (Mäkelä, S. 2008)
It offers a bit of improvement to the TSF in terms of insulation, which reduces heat loss and protects the fire from wind. As seen in the test results shown in
Figure 15, the one-pot mud stove boils water faster than the TSF while using less fuel.
However, similar to the TSF, this stove requires an experienced user since it is difficult to keep the fire going in an efficient way. The biggest disadvantage of the one-pot stove is, as the name implies, it can only work with the pot it was designed for (EPA, 2011a).
Figure 15. Test results for the one-pot mud stove (EPA, 2011a)
Figure 14. One-pot mud stove (MRHP, 2014)
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6.6 Ghana Wood
The Ghana stove is made by a sturdy sheet metal body with a thick ceramic liner inside. This is illustrated in Figure 16.
The pot is placed on three supports on top of the stove and fuel is fed into the fire through a closeable door. The test results shown in figure 17 indicates that the Ghana wood uses slightly less fuel than the TSF but it pollutes more, particularly in terms of PM. The design makes it useful for windy conditions and for simmering food since the stove, with the door closed, retains heat for a long time once the stove body is hot.
Figure 17. Test results for Ghana Wood (EPA, 2011a)
Figure 16. Ghana wood (Toloya Energy, 2006)
23 6.7 VITA stove
The VITA stove is the result of a study, done by Dr.
Sam Baldwin, to inexpensively improve heat transfer and decrease the fuel needed to cook food. It is made from a sheet of metal with three supports for the pan.
The wood is placed on a grate, which allows for air to pass through the fire. Figure 18 shows the VITA stove.
The VITA stove is one of the most fuel-efficient stoves considered in this report and the test results presented in figure 19 shows that it also delivers the best scores on the WBT. However the emissions are
high since it does not have a combustion chamber and the fire is very close to the pot. It will work best with the pot the stove is designed for that fits the opening optimally.
Figure 19. Test results for the VITA stove (EPA, 2011a)
Figure 18. VITA stove (EPA, 2011a)
24 6.8 Save80
Save80 is one of the stoves that UNCHR is using today (Widström, 2014). Save80 is a part of an ongoing project and therefore no actual test results have been provided yet and it has not been a part of the Aprovecho’s studies. Because of this, it is not possible to make a proper comparison between Save80 and the stoves evaluated above. According to Save80
representatives themselves, the fuel consumption is reduced by 80% compared to an open fire.
After a ten year range, the project aims to have reduced CO2 by 300 000 tons (Energia Africa, 2014).
The cost of a Save80 is US$72 and it has been accepted by refugees and agencies as the most robust an efficient stove available (UNHCR, 2012c).
6.9 Ten design principles
As mentioned in section 6.4, Dr. Larry Winiarski conducted in 1982; ten design principles to improve wood burning cook stoves. These are presented below.
1. Insulation around fire
Adding insulation around the fire retains the heat, which increase the amount of PMs being burnt so a more smokeless fire is obtained. Also, the insulation makes the heat flow towards the pot steadier. The insulating material should be lightweight with a lot of air pockets of air, such as wood ash, pumice rock, vermiculate etc.
2. Chimney
A short insulated chimney should be inserted right above the fire. Inserting a chimney, three times taller than its diameter brings hotter gases to the pot. A taller chimney means higher degree of complete combustion and the emissions are reduced. If the chimney is too tall, too much air gets into the system and the rising gases are cooled down.
3. Tip burning
By igniting the tip inserting the wood sticks in a radiate pattern continuously as they burn, smouldering i.e. unburnt gases are reduced and a cleaner combustion is achieved.
4. Number of sticks
The wood as it is heated releases gas, which create heat when they are ignited. The level of heat can be controlled by using few sticks (low heat), or many sticks (high heat).
5. Draft
By maintaining a good draft the temperatures are maintained high and the fire clean.
6. Amount of Draft
If there is too little draft makes the fire smoky and results in excess PMs. Too much draft cools the fire down.
25 7. Constant Cross Sectional Area
The opening into the fire, the combustion chamber and the area in which the combustion air flows and the chimney should have the same cross sectional area. This maintains a good draft throughout the entire stove. A use of this is in TSF (see section 6.3).
8. Grate
Wood sticks or fuel should not be put directly onto the floor of the combustion chamber, but instead on a grate. This allows air to flow underneath the fuel and causes a more complete combustion.
9. Insulation of Heat Flow Path
By insulation the gases are maintained at a higher temperature and therefore can heat up the intended pot and content more efficiently.
10. Proper Size of Gaps
The flowing gases should be inserted via a properly sized gap. The forced flow gives a higher amount of heat in the direction of the pot. If the gap is too big, there is a risk of the gases disappearing without rendering the pot hotter. If they are too small, the risk consist of the gases being cooled down because the draft is not satisfactory.
7. QFD Evaluation
The following section investigates the list of Demanded Qualities in relation to the Quality Characteristics and weighting in the QFD chart one by one. Since the QFD represented below is not developed simultaneously with laboratory tests, the set target values for the Quality Characteristics are based on the competitive analysis in section 6 as well as continuous observations.
Nota Bene
For the QFD chart to be a correct depiction of FirePipe’s situation on the present market, the best result is achieved by performing a market survey to gather specific information on what the customers wants. The survey should entail an evaluation of the below specified functions’
importance (on a scale from “not so important” to “very important”). As well, the survey should give possibility for the answerer to present his/her own Qualities of Demand. In the case with FirePipe, the internal customers are staff at UNHCR and the external are the end- users i.e. people living in refugee camps. The evaluation of the different Demanded Qualities will be divided between the two groups regarding their view of interest.
At the time writing (May 2014), Gustav Innovation is conducting such a survey via UNHCR and the results are expected early summer 2014. The information acquired through the survey will underpin the list of Demanded Qualities and their Weighting from the customers and therefore give a more reliable affidavit by the QFD. The Demanded Qualities and the
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weighing in this document is based on observations of existing similar products and by UNHCR, four, earlier expressed demands regarding Affordability, the Feedstock, Culture and Technology Transfer (Widström, 2014). The USP and earlier work on the FirePipe project are also taken into consideration.
1. Affordable
The first place condition, out of the four by UNHCR expressed demands, is
affordability. Therefore, this quality is weighed by the highest factor – 5. The product must be as cheap as possibly by all means. This comprehensive term therefore
represents a vast number of factors such as keeping production, storing, distribution, implementation, maintenance etc. costs low. This will lead to a, for the customer, low purchase price which also is noted as the corresponding Quality Characteristic for the demand. Since several of FirePipe’s competitors are available at a very low price, some even for free, the conclusion must be made that FirePipe’s sales price cannot exceed US$ 7. This is based on a comparison of the qualities FirePipe offers in relation to the other stoves.
2. Easy logistics
One of the USPs of FirePipe is the facility of how to transport the unassembled product. Increasing the number of products that can be held per unit volume will contribute to a greater affordability since distribution and storing costs will be reduced. The set target value in the QFD is 1.2 x 0.8 m2. This is the size of a wooden pallet (European standard) (Posten, 2014) and is the maximum acceptable size for the unfolded metal sheet to maintain the easy handling of unassembled FirePipes.
3. High fuel efficiency
To keep FirePipe affordable, it is important for the everyday use of the stove to be as cheap as possible. One of the factors affecting this is the stove’s fuel efficiency i.e.
how much energy the stove’s combustion can extract from a set amount of fuel. This can be shown by measuring the mass fuel needed to complete a WBT, which is explained further in section 6.2. The set target value of 750 g per WBT is the result of a weighing of FirePipe’s Demanded Quality in comparison to competing stoves.
4. Ability to save time
Another important quality is the ability to save time i.e. reducing the time needed to boil water. This relates, as well as the fuel consumption, to the thermal efficiency of the stove. For FirePipe to be able to compete with other similar stoves it needs to bring 5 liter to boil in not more than 20:00 min (an average value of hot and cold start
phases of WBT).
5. Withstand rain
The end-users are most likely to be cooking with FirePipe outdoors and therefore it is important for the stove to be resistant towards varying kinds of weather.
27 6. Withstand wind
The cooking stove also has to be able to withstand windy conditions i.e. a moderate breeze (8 m/s) (SMHI, 2012). The stove must protect the fire in such a way it does not go out, nor risking to tip over due to heavy wind. Weather resistance correlates to an increased safety standard as the risk of burning fuel escaping the cooking vessel is minimized if the stove stands steadily.
7. Offer heat regulation
To implement a new stove it is important that the cultural habits of the end-users are not affected by the stove design. If a user has to change a lot of his/hers routine when using a new product, the likelihood of him/her not wanting to use it is more
considerable. Knowing the end-user behavior is a complex issue, which comprehends a number of different aspects. One of them is the ability for end-users to continue cooking the food they are used to. Therefore it is important to offer heat regulation so that the stove can boil, simmer as well as fry to fulfil all the different needs the end- user may have.
8. Give heat
Cold nights call for a heat source in informal settlements and therefore it may be an addition to the design of the stove also serves as a heat source. However, increasing the heat transfer to the ambiance has a strong negative correlation with safety, since the transferred heat increases the risk of fire outbreak. It has also a strong negative correlation with the thermal efficiency of the stove.
9. Give light
Under some circumstances it can be helpful if the stove also serves as a light source and illuminates the surroundings, for example when cooking after dusk. The luminous intensity is measured in candela where 1 Cd corresponds to the emitted light from one candle.
10. Low CO emissions
CO is a toxic substance and has great impact on human health when inhaled (Naturvårdsverket, 2010) and therefore it is very important to minimize these
emissions. This correlates to CO2 emissions since it gives a value of the combustion in total, and how complete it has been.
28 11. Low PM emissions
PM emissions have a negative effect on both health and climate why it is very important to minimize these emissions. This is discussed further in section 3.1.
12. Easy to assemble
To be able to implement FirePipe effectively, the product must be easy to assemble.
Once the stove has been delivered to the end-user, the assemblage must be as easy and consume as little time as possible. One of the USP with FirePipe is that it has a
foldable design and it is important that the procedure to fold is intuitive. Therefore, it should not include more than 10 steps.
13. High ability to assemble
To further facilitate the assemblage of the stove, together with minimizing the economic aspect of having to buy tools, it can be of importance to minimize the number of tools required for the assemblage. Preferably, it should be possible to assemble FirePipe by hand.
14. Easy to feed fuel
To ease the technical transfer from distributor to end-user when implementing a new stove, it is important that it does not complicate the everyday use. Therefore the ability to feed fuel easily is an important aspect of the design. One way to facilitate the fuel supply is to have a large opening for it. For the fuel intended to be used with FirePipe, e.g. pellets, collected sticks of wood etc., an opening of 4x8 cm is considered as appropriate.
15. Easy to ignite
Another aspect is the time needed to ignite a fire from sparkle to full fire. If the design makes the ignition difficult it will not be accepted as easily by the users. The maximal time for ignition is considered to be 1 min, however, how long ignition time that is acceptable for FirePipe’s end-users is another aspect that the forthcoming survey can give answers to.
16. Easy to maintain
Studies made by the National Bureau of Economic Research (NBER) show that people tend to stop using stoves that requires a lot of maintenance to work properly and just preferred to switch back to cooking fires. Therefore it is of great importance that the stove requires as little time for maintenance as possible (Borowski, L. 2012).
The maximal time for maintenance is considered to be 1 hour every week, however, as well as for the accepted ignition time, the survey may give answers on how long the accepted time for maintenance is for FirePipe’s end-users.
29 17. Usable for various pan-sizes
Since different dishes require different pans it is preferable if the stove is usable for various pan-sizes so that it does not limit the cooking for the user.
18. Usable for several pans simultaneously
If possible, it is desirable to use a stove for several pans simultaneously without a negative effect on other more important aspects.
19. Movability
Many situations are facilitated if it is possible to move the stove i.e. when cleaning the stove, when moving etc. Minimizing the weight contributes a lot to the stoves
movability. Therefore, it is important to have the movability in mind when designing the stove so it does not become ungainly. A movable stove shall not weigh more than 7 kilos for the users to be able to move it easily. However, if the stove is too
lightweight the risk of making it unstable and also more unsafe increases.
20. Flexibility
When moving and recycling a stove, it can be an advantage if the design is collapsible.
This must, however, be opposed to that the stove may become more unsteady.
21. Safe
Safety is important and plays a major role when designing stoves. The safety of the stove is measured with a SST (Standard Safety Test) covering many different factors.
The SST is explained further in section 6.2.
30 8. Result and Discussion
The result of the QFD analysis, which is presented graphically in Figure 20, shows the most important Quality Characteristic is to minimize the fuel mass needed using the stove.
Therefore the future development of FirePipe should focus on the achievement of reaching the target value for this requirement. Reducing the fuel consumption of the stove has a number of positive effects. They include minimizing fuel costs, time consumed for collecting fuel, amount of emissions released etc. All together, these advantages generate a better chance for FirePipe to be implemented on the prospected market.
The second most important Quality Characteristic is minimizing the time to bring water to boil. This may, in some cases, have a negative correlation to the third and fourth most important characteristics, which are the minimization of CO and PM emissions.
This is the case because, as with for example the Vita Stove, higher temperature can be achieved by placing the pan closer to the flames. This reduces the time needed to bring water to boil but increases the amount of emissions since less space between the fire and the pan leads to less accessible oxygen. Furthermore, this results in a larger proportion of incomplete combustion and accordingly more emissions of CO and PMs.
Therefore the development of FirePipe should concentrate on finding a design reducing the time to boil and increasing the thermal efficiency preferably without having to place the pan too close to the fire. This can, for example, be achieved by using secondary combustion as discussed in section 4.2. This increases the amount of complete combustion and thereby the thermal efficiency from the fuel, as well as it reduces harmful fumes emitted. Another approach may also be to develop better isolation of the stove to achieve higher thermal efficiency.
Do take note there is no listing of a Demanded Quality concerning Low CO2 emissions. The reason for this is the aim to attain an as complete combustion process as possible, i.e. have the highest achievable CO2/CO ratio as a product of the combustion. As explained in section 4.1, this results in as harmless combustion residues as possible for humans. Bearing in mind from section 3.1, CO2 is a greenhouse gas and the amount emitted should be minimized as well.
The way CO2 is regulated in the QFD however, is via the keeping fuel consumption low.
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Figure 20. Relative weight [%] for the Quality Characteristics. The four most important are marked with red stacks in the figure and bold texting in the list below.
1. Purchase price [USD]
2. Unit area unassembled [m2] 3. Fuel mass needed for WBT [kg]
4. Time to boil [min]
5. Withstand rain [l/m3 per day]
6. Withstand wind [m/s]
7. Ability to boil, simmer, fry [Number of mentioned functions]
8. Ambient temperature increase 5 m from fire [C]
9. Light measured 5 m from stove in dark ambience
10. Amount of CO emissions compared to open fire [%]
11. Amount of PM emissions compared to open fire [%]
12. Steps required to assemble stove [-]
13. Number of tools needed [-]
14. Fuel supply opening size [m2] 15. Ignition time [min]
16. Time for maintenance per week [h]
17. Range of pan diameter [cm]
18. Number of cooking surfaces [-]
19. Weight [kg]
20. Ability to recollapse [Yes/No]
21. High value from SST [-]
Some of the Quality Characteristics receive a low relative weight and the reaching of their target values must therefore be seen as low priority. An example of this is giving light and temperature increase of the surroundings. These characteristics have a negative correlation with some of the requirements with higher importance. The ability to heat to the surroundings will lead to lower the energy flow towards the pan and, which will have a strong, negative effect on the high rated characteristic time to bring water to boil. The full QFD chart presenting all correlations and results is attached in Appendix A. Appendix B shows the correlation matrix and results clearly.
As mentioned, to increase the value of the QFD the weighting of the Demanded Qualities should be audited after obtaining information from the user-survey. The results from the survey might also result in other Demanded Quality factors regarding the usability of the stove, which can affect the results of the QFD.
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For example, the survey might show “High Fuel Efficiency” is not an as strongly Demanded Quality as formulated in the present QFD. This could be the case if the access of fuel is redundant and the Demanded Quality would be weighted as a 1 instead of a 5.
The importance of minimizing the Quality Characteristic with a strong relationship with
“High Fuel Efficiency”, which is first and foremost “Fuel mass needed for WBT” is then somewhat reduced. However, the relative importance for the fuel mass to be minimized remains high due to its strong linkage to a number of other Demanded Qualities in the QFD as well. This network of impact indicates stability in the present QFD affidavit. However, what can have a greater impact on the QFD result is if there are aspects of demand, which have not been considered at all in this analysis. Therefore it is advisable to reassert the results with the survey results before conducting work on technical solutions.
After the QFD results have been confirmed and/or revised the next step is to find technical solutions corresponding to the spotlighted Quality Characteristics. If the user survey confirms the result of the QFD to be acceptable, future work should be focused on how to minimize FirePipe’s fuel use and maximize the thermal efficiency. Examples on how this can be achieved could involve investigating the possibilities to minimize heat transfer through technical design analysis: e.g. dimensions, surface coatings and insulation.
One of the Demanded Qualities from UNHCR has been FirePipe’s cultural applicability for the end-users. As expressed earlier, this is a complex issue regarding a number of factors. The Quality Characteristics of these demands are subjective, so they are hard to overview with the QFD principle. Overall, the focus must be on designing FirePipe in a way maintaining the preservation of habits for the people using it. This means not only allowing the same types of pots and pans to be used, or foods to be cooked but also the operating schedule on how to use a stove.
The most effective way for optimizing the implementation possibilities for the stove would be to work with continuous feedback from end-users when testing new design alternatives.
The QFD analysis of competition shows FirePipe has a relatively good position amongst its competitors, based on the set target values for FirePipe characteristics. FirePipe is rarely the best alternative among the evaluated stoves, nor the worst in most Demanded Quality categories which overall makes FirePipe qualitatively consistent. Note Bene the analysis of competition is based on the adoption that FirePipe complies all the set target values for the Quality Characteristics. If these requirements are not met, FirePipe’s position will deteriorate.
For example, the target values for released emission were, because of their high relative weight, set to not be inferior of the Rocket Stoves values. That ranked FirePipe as the best stove to fulfil those Demanded Qualities, which will not be the case if FirePipe does not meet these values.
3
The deficiencies of the competitive analysis must also be considered. It ranks the stove, which is considered the best with 5 and the worst with 1, not taking into account how big the quality differences are between the different rankings.
When evaluating the competitive market, there is always an uncertainty on which other products to focus on. As said earlier in section 6.1, the ones which have been evaluated are established stoves among the, for FirePipe, intended user group. Since the work concerning this report, does not entail lab tests, results from the research study done by Appravecho Research Center have been fundamental in order to be able to make any comparison in between stoves which meant choosing stoves included in that study.
9. Conclusion
The results discussed in the previous section show that FirePipe has possibilities to become a strong competitor in the specified customer group. Before this can be achieved, some Quality Characteristics of the product must be improved in order for it to be an outstanding product in comparison to similar stoves. The QFD analysis points out some characteristics which have a big need of improvement for FirePipe. They are as follows: the need to minimize fuel usage, the time to boil, the emissions of carbon monoxide as well as PMs. If the product can improve its performance in these areas it is likelier to become a successful product. Future work on the project should therefore be to find technical solutions to the above mentioned characteristics.
To underpin the affidavit of the QFD analysis conducted in this report, it should be completed with direct information from customer survey results with UNHCR personnel and people in refugee camps. By doing so, errors which might have occurred throughout the work in the present analysis can be discovered and corrected.
