Application of QFD and Value Engineering Concepts in Product Development of Commercial Ventilation System Exhaust Hood

M.S Ramaiah School of Advanced Studies –Postgraduate Engineering and Management Programmes (PEMP)

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Application of QFD and Value Engineering

Concepts in Product Development of Commercial

Ventilation System Exhaust Hood

M.Sc [Engg.] Dissertation in

Engineering and Manufacturing Management

Submitted by: Pranava Audithan A

Registration No: BUB0908001

Academic Supervisor: N. Sandeep Assistant Professor, MSRSAS

Industry Supervisor: N.A.Mohan

Envirotech Engineering & Systems,

Pondicherry

M.S. RAMAIAH SCHOOL OF ADVANCED STUDIES Postgraduate Engineering and Management Programme

Coventry University (UK) #470-P Peenya Industrial Area, 4

th Phase, Bengaluru-560 058

Tel: 080 4906 5555, website: www.msrsas.org

March-2011

M.S Ramaiah School of Advanced Studies –Postgraduate Engineering and Management Programme (PEMP)

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M.S.RAMAIAH SCHOOL OF ADVANCED STUDIES

Postgraduate Engineering and Management Programme

Coventry University (UK)

Bangalore

Certificate

This is to certify that the M.Sc (Engg) Project Dissertation titled

“Application of QFD and Value engineering concepts in product

development of commercial ventilation system exhaust hood” is a bonafide

record of the Project work carried out by Mr.A.Pranava Audithan Reg.No.

BUB0908001 in partial fulfilment of requirements for the award of

M.Sc (Engg) Degree of Coventry University in

Engineering and Manufacturing Management.

March-2011

Mr.N.Sandeep Assistant Professor Academic Supervisor MSRSAS

N.A.Mohan Dr.N.S.Mahesh Industrial Supervisor HOD (MME)

EES, Pondicherry MSRSAS

Dr.Govind R. Kadambi Deputy-Director (Academics)

MSRSAS


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Declaration

‘‘AApppplliiccaattiioonn QQFFDD aanndd VVaalluuee EEnnggiinneeeerriinngg ccoonncceeppttss iinn pprroodduucctt ddeevveellooppmmeenntt

ooff ccoommmmeerrcciiaall vveennttiillaattiioonn ssyysstteemm eexxhhaauusstt hhoooodd’’

The Project Dissertation is submitted in partial fulfilment of academic requirements for

M.Sc (Engg) Degree of Coventry University in Engineering and Manufacturing

Management. This dissertation is a result of my own investigation. All sections of the text

and results, which has been obtained from other sources, are fully referenced. I

understand that cheating and plagiarism constitute a breach of University regulations and

will be dealt with accordingly.

SSiiggnnaattuurree::

NNaammee ooff tthhee SSttuuddeenntt:: PPrraannaavvaa AAuuddiitthhaann.. AA

RReeggiissttrraattiioonn NNoo:: BBUUBB00990088000011

DDaattee:: 3300--0033--22001111


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Acknowledgement

I would like to first acknowledge Envirotech for their support to accomplish this

work. My experience was richly rewarding, fun and insightful and I owe a lot to the

people who made my project possible. I want to especially thank Mr.N.A.Mohan

(Proprietor, Envirotech Engineering and Systems) for creating the project and giving

me an opportunity to work for Envirotech.

My highest regard of appreciation and deepest gratitude to Mr. N.Sandeep Assistant

Professor, MSRSAS for his continuous motivation and guidance not only during the

project but throughout the entire academic semesters. His dedication, keenness and

thought provocations pushed me to put my level best into the project. I wish to extend my

whole hearted thankfulness to Dr.N.S.Mahesh, HOD - MME, MSRSAS for his timely

reviews, monitoring and guidance throughout the project. I wish to extend my sincere

gratitude to all the faculty members of Centre for Manufacturing, MSRSAS:

Dr.K.Gnanamurthy, Professor.V.G.S Mani, Professor.B.S.Ajithkumar,

Professor.Ramadas Chandrasekhar, Assistant Professor Ganapathi and Mr. Vijay

Kumar for the valuable and effective teachings imparted during the academic modules.

Finally, none of this would have been possible without the love and support of my

family. I thank them for their never ending encouragement, patience and sacrifices.


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Abstract

In an increasingly intense competitive environment, it is of paramount importance for

organizations to achieve highly efficient products, low costs and high customer service

level to survive. Value engineering provides an organization with the tools that improves

its ability to plan, implement and control its activities as well as the ways in which

organization uses its resources in an effective and productive manner.

In this project, attempt has been made to apply the concepts of Value engineering and

Quality function deployment, in product development of Commercial Ventilation Exhaust

hood. The selected product data’s were gathered and studied in the information phase.

Brainstorming and Quality function deployment were carried out to identify the problems.

The selected ventilation principles were applied in the new concept of the Capture jet

Kitchen Exhaust hood and Cyclonic grease filters. The newly designed concepts were

modelled in 3 dimension using CATIA and the meshing was carried out using Star CCM

commercial CFD solver.

For inlet, four mass flow rates (0.5, 1, 3, 5 kg/s) were imposed using the fixed mass inlet

boundary condition. The value of density (1.2 kg/m3

), total pressure (1 atm) and

turbulence intensity (5%) were specified at the inlet boundary. For outlet, outflow

boundary condition was imposed with Pressure outlet (3bar). No slip boundary condition

was applied on all wall surfaces. For main filter media, porous media boundary was

imposed with pi = 2500 and p

v= 3000. Whole domain was considered at 1 atm and at

298K as initial condition.

Based on the Capture and containment analysis done for the Exhaust only hood and

Capture jet model hoods, the capture jet model was 50% more efficient and air flow rates

are 30% lower than those of an exhaust-only hood system. The need for replacement air is

reduced as well. The capture jet model is not only saving energy but also improves

productivity by providing a comfortable thermal environment.


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Table of Contents

Certificate...........................................................................................................................ii

Declaration........................................................................................................................ iii

Acknowledgement .............................................................................................................iv

Abstract ............................................................................................................................... v

Table of Contents ..............................................................................................................vi

List of Figures ....................................................................................................................ix

1 – Introduction .................................................................................................................. 1

1.1 Commercial Kitchen Ventilation Systems ................................................................. 1

1.2 Company background ................................................................................................. 2

2 – Background Theory ..................................................................................................... 4

2.1 Commercial Kitchen Ventilation System................................................................... 4

2.2 Value engineering/ Value analysis .............................................................................. 5

2.3 Computational Fluid Dynamics .................................................................................. 6

3 – Literature Review ........................................................................................................ 8

3.1 Quality function deployment ...................................................................................... 8

3.2 Value engineering......................................................................................................... 9

3.3 Kitchen Ventilation .................................................................................................... 10

3.4 Summary of Literature Review ................................................................................ 12

4 – Problem Definition ..................................................................................................... 13

4.1 Problem Statement..................................................................................................... 13

4.2 Objectives.................................................................................................................... 13

4.3 Methodology ............................................................................................................... 14

5 – Data Collection and Analysis .................................................................................... 15

5.1 Flow Chart .................................................................................................................. 15

5.1.1 Pre- workshop study ............................................................................................... 15

5.1.2 Workshop Study...................................................................................................... 16


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5.1.3 Post Workshop Study ............................................................................................. 16

5.2 Information phase ...................................................................................................... 16

5.2.1 Product Data............................................................................................................ 16

5.2.2 House of Quality ...................................................................................................... 17

5.3 Functional analysis..................................................................................................... 17

5.3.1 Ventilation Principle – Mixing Ventilation system .............................................. 17

5.3.2 Exhaust Hood .......................................................................................................... 19

5.3.3 Baffle filters ............................................................................................................. 20

5.4 Creative phase ............................................................................................................ 21

5.4.1 Ventilation principle – Thermal Displacement Ventilation ................................ 21

5.4.2 Combined Exhaust Hoods and Supply Inlets ....................................................... 22

5.4.3 Air jets ...................................................................................................................... 24

5.4.4 Cyclone filters .......................................................................................................... 24

5.5 Evaluation Phase ........................................................................................................ 26

6 – Problem solving .......................................................................................................... 27

6.1. Development Phase ................................................................................................... 27

6.2 Concept generation .................................................................................................... 27

6.2 Working of Capture jet hood Concept .................................................................... 28

6.3 Working of Cyclonic grease filter concept .............................................................. 29

7 – Results and Discussions ............................................................................................. 30

7.1. GEOMETRY MODEL ............................................................................................. 30

7.1.1 CFD MESHING ...................................................................................................... 31

7.1.2 CFD MODEL DESCRIPTION ............................................................................. 32

7.1.3. GOVERNING EQUATIONS ............................................................................... 33

7.1.4 BOUNDARY CONDITIONS ................................................................................. 34

7.2 Results and discussions .............................................................................................. 34

7.2.1 Residual plot ............................................................................................................ 41

7.2.2 Capture efficiency vs. inlet airflow ........................................................................ 43

7.2.2 Heat gain vs. air flow .............................................................................................. 43


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8 - Conclusions.................................................................................................................. 45

8.1 Conclusion .................................................................................................................. 45

8.2 Recommendations ..................................................................................................... 46

References ......................................................................................................................... 47


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List of Figures

Figure 1. 1 kitchen ventilation system ................................................................................. 2

Figure 1. 2 various kitchen equipments ............................................................................... 3

Figure 2. 1 styles of commercial kitchen exhaust hoods [7]................................................ 5

Figure 2. 2- examples of CFD applications [10] .................................................................. 7

Figure 5. 1 flow chart of value engineering ....................................................................... 15

Figure 5. 2 house of quality (QFD) .................................................................................... 17

Figure 5. 3 typical mixing ventilation [13] ........................................................................ 18

Figure 5. 4 Wall mounted canopy[7] ................................................................................. 20

Figure 5. 5 Baffle filter ...................................................................................................... 21

Figure 5. 6 Displacement Ventilation[13] ......................................................................... 22

Figure 5. 7 Schematic diagram of trajectories[13] ............................................................. 25

Figure 5. 8 collection efficiency curve of a cyclone[13] ................................................... 25

Figure 6. 1 capture jet exhaust hood .................................................................................. 27

Figure 6. 2 capture jet exhaust hood concept ..................................................................... 27

Figure 6. 3 Working of Capture jet exhaust hood concept ................................................ 28

Figure 6. 4 Working of Cyclonic grease filter concept ...................................................... 29

Figure 7. 1 Capture jet hood model ................................................................................... 30

Figure 7. 2 Normal exhaust hood model. ........................................................................... 30

Figure 7. 3 Filter in Capture jet .......................................................................................... 31

Figure 7. 4 Filter in Normal Exhaust Hood ....................................................................... 31

Figure 7. 5 Volume Tetrahedral mesh ............................................................................... 32

Figure 7. 6 Volume Polyhedral Mesh ................................................................................ 32

Figure 7. 7 Velocity at outlet section ................................................................................. 34

Figure 7. 8 Velocity at inlet section (circulations @inlet) ................................................. 35


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Figure 7. 9 velocity vector plot .......................................................................................... 35

Figure 7. 10 Pressure contour of Whole hood ................................................................... 36

Figure 7. 11 Pressure contour of filter ............................................................................... 36

Figure 7. 12 Pressure contour of exhaust section .............................................................. 37

Figure 7. 13 Pressure contour of intake section ................................................................. 37

Figure 7. 14 Pressure contour of hood ............................................................................... 38

Figure 7. 15 Pressure contour of section ............................................................................ 38

Figure 7. 16 Temperature contour of section ..................................................................... 39

Figure 7. 17 Vortices contours ........................................................................................... 39

Figure 7. 18 Temperature contour of exahust section........................................................ 40

Figure 7. 19 Conduction heat flux contours....................................................................... 41

Figure 7. 20 Residual plot of Capture jet model ................................................................ 41

Figure 7. 21 Residual plot of Exhaust hood model ............................................................ 42

Figure 7. 22 Capture efficiency vs inlet airflow ................................................................ 43

Figure 7. 23 heat gain vs air flow ...................................................................................... 44

M.S Ramaiah School of Advanced Studies –Postgraduate Engineering and Management Programmes (PEMP)

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1 – Introduction

1.1 Commercial Kitchen Ventilation Systems

Concerns over the indoor environment have increased during recent years as a result

of knowledge about the significance of thermal conditions and air quality on the health,

comfort and productivity of workers. In a commercial kitchen, working conditions are

especially demanding. There are four main factors affecting thermal comfort, these being:

Air temperature

Radiation

Air velocity

Air humidity

At the same time, high emission rates of contaminants are released from the cooking

process. Ventilation plays an important role in providing comfortable and productive

working conditions and in securing contaminant removal.

Labour shortage is a big challenge in commercial restaurants. One reason for the low

popularity of kitchen work is the unsatisfactory thermal conditions.

Ventilation and air conditioning systems are required in commercial kitchens to:

Remove odours and particles of fat

Comply with hygiene requirements

Remove moisture and heat that is generated from the preparation of meals and

washing

Provide comfortable and productive working conditions.

To meet these tasks, supply and exhaust air systems shall be installed in the kitchen

areas so that odours, air pollutants, extra heat and moisture are removed. [8]


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Figure 1. 1 kitchen ventilation system

Figure 1.1 displays a typical wall mounted exhaust hood with baffle filters.

1.2 Company background

Envirotech Engineering and was founded in 1996 in Pondicherry, India as a

commercial ventilation systems provider, specialised in Kitchen ventilation systems for

hotels, restaurants, institutional cooking establishments, etc. In 2006 Envirotech started

manufacturing commercial kitchen equipment and has created a niche market in complete

turnkey establishment of commercial kitchen. The company operates with two registered

offices in Ernakulam and Pondicherry and follows the make-to-order approach. Figure

1.2 shows a snapshot of some of the products manufactured by the organisation.



Figure 1. 2 various kitchen equipments



2 – Background Theory

2.1 Commercial Kitchen Ventilation System

Kitchen ventilation is a complex application of HVAC systems. System design

includes aspects of air conditioning, fire safety, ventilation, building pressurization,

refrigeration, air distribution, and food service equipment. Kitchens are in many

buildings, including restaurants, hotels, hospitals, retail malls, single- and multifamily

dwellings, and correctional facilities. Each building type has special requirements for its

kitchens, but many basic needs are common to all. Kitchen ventilation has at least two

purposes:

To provide a comfortable environment in the kitchen and

To enhance the safety of personnel working in the kitchen and of other building

occupants.

Comfort criteria often depend on the local climate, because some kitchens are not air

conditioned. The ventilation system can also affect the acoustics of a kitchen. Kitchen

ventilation enhances safety by removing combustion products from gas- or solid-fuelled

equipment.

The centrepiece of almost any kitchen ventilation system is an exhaust hood, used

primarily to remove cooking effluent from kitchens. Effluent includes gaseous, liquid,

and solid contaminants produced by the cooking process, and may also include products

of fuel and even food combustion. These contaminants must be removed for both comfort

and safety; effluent can be potentially life-threatening and, under certain conditions,

flammable. The arrangement of food service equipment and its coordination with the

hood(s) greatly affect kitchen operating costs.

HVAC system designers are most frequently involved in commercial kitchen

applications, in which cooking effluent contains large amounts of grease or water vapour.

Residential kitchens typically use a totally different type of hood. The amount of grease



produced in residential applications is significantly less than in commercial applications,

so the health and fire hazard is much lower. [7]

Figure 2. 1 styles of commercial kitchen exhaust hoods [7]

Figure 2.1 shows the various styles of commercial kitchen exhaust hoods.

2.2 Value engineering/ Value analysis

The Society of American Value Engineers (SAVE) defines value engineering as

follows: ―Value engineering is the systematic application of recognized techniques which

identify the functions of a product or service, establish a monetary value for that function,

and provide the function at the lowest cost.‖

However, value engineering is not merely a cost-cutting program. It only cuts

unnecessary costs, which are the costs that can be removed without affecting the

functional performance of the product or service. The new design coming out of a value-

engineering project should have the same or better functional performance than the old

design. It has been estimated that for the average product or service, 30 percent of its cost



is unnecessary. This unintentional cost is the result of habits, attitudes, and all other

human factors.

Value engineering originated at General Electric Company in 1947. Harry

Erlicher, Vice-President of Purchases, noted that during wartime, it was frequently

necessary to make substitutions for critical materials that not only satisfied the required

functions but also had better performance and lower cost. He reasoned that if it was

possible to do this in wartime, it might be possible to develop a system that could be

applied to normal operations to increase the company’s efficiency and profit. L. D. Miles

was assigned to study the possibility, and the result was a systematic approach to problem

solving based on functional performance, which he called value analysis.

Value analysis, value engineering, value management, value assurance, and value

control are all the same in that they make use of the same set of techniques developed by

Miles in 1947. In many cases, the title tends to describe how the system is being applied.

Value analysis is applied to remove cost from a product. Value engineering and value

assurance are applied in the development phase to keep cost out of a product. Value

management and value control are overall programs that apply value techniques in

business operations.

Value engineering was first applied in product development, manufacturing, and

the construction industry, and in the 1970s, value engineering began to be applied in the

service industry. David Reeve’s case study (1974, 1978) on youth service bureaus was

among the first successful case studies in a service organization. Since then, successful

value engineering service case studies have been reported in retail, finance, health care,

photo shops, and many other areas. [11]

2.3 Computational Fluid Dynamics

Computational Fluid Dynamics (CFD) is the branch of fluid dynamics providing a cost-

effective means of simulating real flows by the numerical solution of the governing

equations. The governing equations for Newtonian fluid dynamics, namely the Navier-



Stokes equations, have been known for over 150 years. However, the development of

reduced forms of these equations is still an active area of research, in particular, the

turbulent closure problem of the Reynolds- averaged Navier- Stokes equations. For non-

Newtonian fluid dynamics, chemically reacting flows and two phase flows, the theoretical

development is at less advanced stage.

Experimental methods has played an important role in validating and exploring the limits

of the various approximations to the governing equations, particularly wind tunnel and rig

tests that provide a cost-effective alternative to full-scale testing. The flow governing

equations are extremely complicated such that analytic solutions cannot be obtained for

most practical applications.

Computational techniques replace the governing partial differential equations with

systems of algebraic equations that are much easier to solving using computers. The

steady improvement in computing power, since the 1950’s, thus has led to emergence of

CFD. This branch of fluid dynamics complements experimental and theoretical fluid

dynamics by providing alternative potentially cheaper means of testing fluid flow

systems. It also can allow for the testing of conditions which are not possible or extremely

difficult to measure experimentally and are not amenable to analytic solutions. [12]

Figure 2.2 shows a few examples of aerodynamic applications of CFD.

Figure 2. 2- examples of CFD applications [10]



3 – Literature Review

3.1 Quality function deployment

Mark A.Vonderembse et.al (1997), demonstrated that Quality function deployment offers

product development teams the opportunity to achieve significant improvements over

traditional product development practices. The results show that QFD is able to simplify

the manufacturing process, but overall product costs appear to be only slightly less when

QFD is applied than when traditional practices are used. This study has developed few

measures of the organisational dimensions of QFD, the project’s profile, product design

and resource consumption. The structural model indicates that better product designs may

be created when the project is highly visible and the organisations use cross functional

team based practices. Additional empirical research in this area is needed to substantiate

the results. [1]

Lin Chih cheng (2003) interpreted the QFD methodological characteristics in a structured

manner and he further offers a guide for intervention in product development systems in

organisations. This paper is a product of an action research program on implementing the

QFD method into product development systems in Brazilian industrial organisations. This

work on application of QFD in product development is encapsulated by the conciliation

of the binomial theory practice, through bi-directional movement of reinforcing one

another – good understanding of methodological theory leading to effective practice and

concurrently, good understanding of methodological theory leading to effective practice

continuously generating or refining existing methodological theory. The author believes

that the accumulation of knowledge of QFD comes in three interrelated forms:

1. Refinement of its methodological basis

2. Refinement of operating guides, procedures and rules

3. Construction of models of reference applications.

This paper aims at the first two forms. [2]



3.2 Value engineering

James R.Wixson (1987) illustrated the important distinction between performing new

product development with Value Engineering and the traditional approach is that having

early visibility of high estimated production cost permits discontinuing the project or re-

evaluating the requirements before significant ―sunk‖ costs are committed. The author has

explained that primarily, the value technique eliminates the propensity toward bounded

rationality through the interdisciplinary task team approach to problem identification,

solving that goes far beyond that which an individual can accomplish by himself. He

further illustrated that the synergetic group approach makes value management a unique

tool that can be used to, not only improve the efficiency and effectiveness of new product,

but also reduce the overall per unit cost of the new product by first reducing the sunk-

costs of development and secondarily reducing the recurring cost of manufacturing the

product.[3]

Biren Prasad (1998) has extended the initial idea of combining market research data with

QFD to include value engineering. By integrating Technical importance ratings (TIR) and

Customer importance ratings (CIR) with value engineering and value graphs, product

designers can obtain priorities (relative preferences) on QC functions. The author has

developed a template which can be used for carrying out the following value-based

synthesis:

1. Assess how an organisation perceives its product ranks relative to competitor

(technical competitive assessment).

2. Prioritize ratings that identify relative importance of each of the product solutions

(quality characteristics).

3. Prioritize how a competitor’s product performs relative to each of the chosen

quality characteristics (benchmark data).



4. Compute weighed sum of QCS with respect to both the customer preferences and

those based on value engineering. [4]

Fabio et.al (2004), evaluated the integrated use of the QFD and VA tools by employing a

structured methodology in a survey that was carried out to reveal consumers requirements

concerning a sports bicycle. The quality function deployment with value analysis (QFVA)

is the new tool obtained from the fusion of the QFD and the VA. The QFVA aims at

fulfilling consumer requirements and supplying financial decision parameters that are

based on company formal engineering terms.

First this method quantifies and qualifies each one of the implicit and explicit

requirements acquired. Then it arranges them as unique engineering requirements with

their interrelationship, fulfilling all the consumer requirements according to their ranking.

This kind of analysis is more appropriate when a consumer of a certain product becomes

more exigent and critical of the products. That is when the differentiation level of a

product matters to the consumer. [5]

3.3 Kitchen Ventilation

Andrey et.al (2005) has compared the application of traditional mixing ventilation system

and thermal displacement ventilation system in a typical kitchen environment using

computational fluid dynamics (CFD) modelling. Often kitchen exhaust hoods are

provided with untempered makeup air. It is not uncommon to hear the claim that this

makeup air is exhausted through the hood without having any effect on kitchen space

temperature. The validity of this claim is analyzed in this paper for two makeup air

configurations using a combination of measured data and results from CFD models.

Kitchen space temperature increase is calculated as a result of supplying unconditioned

makeup air during the summer.

A theoretical equation was developed to account for temperature rise in a kitchen when

hoods are not capturing or untempered hot outside air is supplied into a kitchen space.



Delivering untempered makeup air into a kitchen on a hot summer day may result in

temperature rise in a kitchen 10°F (5.5°C) and higher above the comfort level. Such a

high temperature may result in 30% productivity loss of kitchen personnel.

Thermal Displacement Ventilation cooled the kitchen space more effectively than the

mixing ventilation system. The CFD simulation results demonstrate up to 10°F (5.5°C)

lower temperature in the kitchen when the mixing air distribution system was replaced

with a Thermal Displacement Ventilation system having the same cooling capacity. [8]

Risto et.al (2003) has evaluated the influence of a capture jet in a ventilated ceiling and

has found that it is possible to improve the total effectiveness of the ventilation system.

This means better indoor air quality and thermal comfort. In addition, the energy

consumption of a capture jet ceiling is lower than that of a traditional ceiling concept.

This paper demonstrates that the supply air distribution strategy has a remarkable

influence on pollution removal effectiveness and the thermal environment in kitchens. For

a ventilated ceiling, the capture jet could improve the total effectiveness of the ventilation

system by reducing the average contaminant level in the occupied zone by 40 %. In

addition the estimated energy saving potential can be as much as 23 %.

Based on this study, the capture efficiency is not improved after a certain level of exhaust

air flow rate, even if flow rates are increased. Therefore, the main point is to optimise the

requested exhaust air flow rate and to adjust it for the existing convective load of kitchen

appliances. The amount of air carried in a convective plume should be theoretically

calculated and adjusted by matching the exhaust air flow rate. [9]

Risto et.al (2003) has derived a capture efficiency model and it is used to estimate the

efficiency of a ventilated ceiling. This paper demonstrates that a simple equation that

includes the average contaminant level in the occupied zone and the exhaust

concentration could be a suitable platform for capture efficiency analysis in both

measurements and simulations. With a ceiling height of 2.3 m, the capture and

containment efficiency can be as high as 85 - 90 %; with a 2.6 m ceiling height it is 80 –



85 %. These values are quite reasonable compared with the capture efficiency of a default

hood in the German code of practice (VDI, 1984). [10]

3.4 Summary of Literature Review

QFD is able to simplify the manufacturing process, but overall product costs

appear to be only slightly less when QFD is applied than when traditional

practices are used.

Performing new product development with VE gives an edge by having early

visibility of high estimated production cost, permits discontinuing the project or

re-evaluating the requirements before significant ―sunk‖ costs are committed.

The quality function deployment with value analysis (QFVA) is the new tool

obtained from the fusion of the QFD and the VA.

The QFVA aims at fulfilling consumer requirements and supplying financial

decision parameters that are based on company formal engineering terms.

The supply air distribution strategy has a remarkable influence on pollution

removal effectiveness and the thermal environment in kitchens. For a ventilated

ceiling, the capture jet could improve the total effectiveness of the ventilation

system by reducing the average contaminant level in the occupied zone by 40 %.

In addition the estimated energy saving potential can be as much as 23 %.



4 – Problem Definition

In an increasingly intense competitive environment, it is of paramount importance for

organizations to achieve quality products, low costs and high customer service level to

survive. The aim of both value analysis (VA) and quality function deployment (QFD) is

to reduce waste by avoiding redesign and providing optimal location of costs in general.

To satisfy the consumer’s most important needs, the VA prioritizes the increase in the

cost of the product and not the subsequent price rise. QFD aims at generating clear

engineering needs from consumer requirements thus, minimizing the re-projecting cost

(―cost‖ should read ―waste‖) and changes in the products. [5]

In Envirotech there is tremendous pressure to relook at designs, engineering practices and

processes which are decades older. Globalisation has enabled customers to access any

product in the world without any barriers. So it has become extremely important to

provide products with the best quality at lowest cost and after sales service. Envirotech is

facing lots of difficulties as new companies are entering into commercial ventilation

business. Increasing competition and increasing raw material costs, higher taxes and

higher wages are increasing price so it is of ultimate necessity to innovate in order to

stand out of the crowd.

4.1 Problem Statement

The aim of this project is to apply Quality Function Deployment and Value

Engineering concepts in product development of commercial ventilation system exhaust

hood for value addition.

4.2 Objectives

Survey the literature on implementation of QFD and VE concepts in product

development and manufacturing industries.



Analyze current design techniques and manufacturing processes of the selected

product.

Identify the benefits of implementing QFD and VE techniques in terms of function-

cost-worth with regards to the selected product.

Propose modifications based on the outcomes.

Implement the outcomes in the selected product development and measure the

benefits in new design (Prototype).

4.3 Methodology

Literature survey on QFD and Value engineering concepts and various methods for

successful implementation. Understanding how the VE concepts can be applied to

product development process by referring journals, books, manuals and related

documents

Collecting information regarding materials, functionality and processes involved in

the selected product.

Plotted the VE job plan to schedule selection of product, identifying problem, setting

goals etc.

Used QFD, brainstorming techniques to identify the opportunities for improvements.

CFD analysis was carried out to identify the benefits.

Prototype exhaust hoods were fabricated to check for desired function

Measuring the benefits in terms of functional quality and cost.



5 – Data Collection and Analysis

5.1 Flow Chart

Figure 5.1 shows a typical flow chart of VE. Basically it is divided into 3 categories

namely Pre-workshop study, Workshop study and Post-workshop study.

5.1.1 Pre- workshop study

It is the analysis which is done before starring any VE project. This is completely

management guided process. This stage includes activities as mentioned below:

Management approval for VE project

Develop scope and objectives

Obtain documents such as specifications, drawings, project estimates etc

Gather information about customer and user

Invite customers, suppliers and stake holders to participate in the VE project

Form a VE team

Define the requirements to senior management for success of VE project

Figure 5. 1 flow chart of value engineering



5.1.2 Workshop Study

Workshop study is the phase where value addition will be very high as compared to any

other phases. This phase is systematically divided into 6 parts as following.

Information: All possible data needed to proceed with the project is collected

Functional analysis: Product or process is analysed for its function, cost and

performance

Creative: This stage provides a major contribution to the project where actual

work is done in several iterations until the desired result is achieved.

Evaluation: Affect of ideas on project cost of performance, selection and

prioritization of ideas for developments.

Development: Cost benefit analysis, develop action plan for implementing steps.

Presentation: Prepare presentation and supportive documents; give the comparison

of costs, functions and benefits of new VE model.

5.1.3 Post Workshop Study

This stage is more related to the implementation activity where action plans are

established, continuous follow up is done to monitor the status of the project, track

achievements etc.

5.2 Information phase

5.2.1 Product Data

Material: Stainless Steel 20G 304 grade.

Manufacturing process: The sheet metal is sheared and bending is carried out. The joining

process is done by TIG welding.



5.2.2 House of Quality

Figure 5. 2 house of quality (QFD)

Figure 5.2 shows the house of quality built based on the Quality function deployment

carried out to analyse the voice of the customer.

Based on the House of quality the functionality tops the priority of the customers

followed by reliability and serviceability.

5.3 Functional analysis

5.3.1 Ventilation Principle – Mixing Ventilation system

The Ventilation principle followed by Envirotech is Mixing Ventilation. In this system,

mixed air supply diffusers supply high velocity air at the ceiling level. This incoming air

is ―mixed‖ with room air to satisfy the room temperature set point. Theoretically there

should be a uniform temperature from floor to ceiling. However, since commercial

kitchens have a high concentration of heat, stratification naturally occurs. Consequently,

the conditioned air does lose some of its cooling effectiveness, gaining in temperature as



it mixes with the warmer air at the ceiling. Figure 5.3 shows typical mixing ventilation.

[13]

Figure 5. 3 Typical mixing ventilation [13]

Advantages of “Mixing” Ventilation:

This type of ventilation allows heat recovery and preheating of supply air.

Supply air is targeted to occupied zones, while air is extracted room polluted zone

Absence of high suction pressures reduces the risk of backdraughting as well as

the entry of radon or soil gas.

Filtration of the incoming air is possible.

Disadvantages of “Mixing” Ventilation:

Two systems are present, thus doubling installation and operational costs.

The systems have been shown to require regular long term maintenance.

For correct operation, these systems must be installed in airtight enclosures. This

reduces safety margins if the system fails to operate correctly or if the occupant

unwittingly introduces high polluting sources into the building. [13]



5.3.2 Exhaust Hood

The centrepiece of almost any kitchen ventilation system is an exhaust hood, used

primarily to remove cooking effluent from kitchens. Effluent includes gaseous, liquid,

and solid contaminants produced by the cooking process, and may also include products

of fuel and even food combustion. These contaminants must be removed for both comfort

and safety; effluent can be potentially life-threatening and, under certain conditions,

flammable. The arrangement of food service equipment and its coordination with the

hood(s) greatly affect kitchen operating costs.

Hood Types

Many types, categories, and styles of hoods are available, and selection depends on many

factors. Hoods are classified by whether they are designed to handle grease; Type I hoods

are designed for removing grease and smoke, and Type II are not. Model codes

distinguish between grease-handling and non-grease-handling hoods, but not all model

codes use Type I/Type II terminology. A Type I hood may be used where a Type II hood

is required, but the reverse is not allowed. However, characteristics of the equipment and

processes under the hood, and not necessarily the hood type, determine the requirements

for the entire exhaust system, including the hood.

A Type I hood is used for collecting and removing grease particulate, condensable

vapour, and smoke. It includes (1) listed grease filters, baffles, or extractors for removing

the grease and (2) fire-suppression system. Type I hoods are required over cooking

equipment, such as ranges, fryers, griddles, broilers, and ovens, that produce smoke or

grease-laden vapours.

A Type II hood collects and removes steam and heat where grease or smoke is not

present. It may or may not have grease filters or baffles and typically does not have a fire-

suppression system. It is usually used over dishwashers. A Type II hood is sometimes

used over ovens, steamers, or kettles if they do not produce smoke or grease-laden vapour

and if the AHJ allows it. [7] Figure 5.3 shows a typical Wall-mounted canopy, used for

all types of cooking equipment located against a wall.



Figure 5. 4 Wall mounted canopy[7]

5.3.3 Baffle filters

Baffle filters (Fig 5.5) have a series of vertical baffles designed to capture grease and

drain it into a container. The filters are arranged in a channel or bracket for easy insertion

and removal for cleaning. Each hood usually has two or more baffle filters, which are

typically constructed of aluminium, steel, or stainless steel and come in various standard

sizes. Filters are cleaned by running them through a dishwasher or by soaking and rinsing.

NFPA Standard 96 requires that grease filters be listed. Listed grease filters are tested and

certified by a nationally recognized test laboratory under UL Standard 1046.



Figure 5. 5 Baffle filter

5.4 Creative phase

5.4.1 Ventilation principle – Thermal Displacement Ventilation

In the commercial kitchen environment the supply airflow rate required to ventilate the

space is a major factor contributing to the system energy consumption. Traditionally high

velocity mixing or low velocity mixing systems have been used. Now there is a third

alternative that clearly demonstrates improved thermal comfort over mixing systems, this

is displacement ventilation.

Thermal displacement ventilation is based on the natural convection of air, namely, as air

warms, it will rise. This has exciting implications for delivering fresh, clean, conditioned

air to occupants in commercial kitchens.

Instead of working against the natural stratification in a kitchen, displacement ventilation

first conditions the occupied zone and, as it gains heat, continues to rise towards the upper

unoccupied zone where it can be exhausted. Displacement ventilation is a form of balanced ventilation in which the supply air

displaces rather than mixes with the room air. Preconditioned air at 2 to 3K below

ambient room temperature is introduced to the space at a low level and at a very low

velocity (typically 0.1 to 0.3m/s). Gravitational effects encourage the incoming air to

creep at floor level until it reaches a thermal source (occupant, electrical load, etc). The

air then rises around the heat source and into the breathing zone prior to extraction at



ceiling level. This approach is designed to avoid the mixing of air; instead, it displaces the

air already present within the space. It therefore has high air change efficiency. Air supply

diffusers are usually either free standing or located in the floor. A large total area of

diffuser over which the air is uniformly discharge is needed to accomplish the required

volume low rate at low supply velocity. Figure 5.5 shows a typical displacement

ventilation system. [13]

Figure 5. 6 Displacement Ventilation[13]

5.4.2 Combined Exhaust Hoods and Supply Inlets

These systems can be inside large halls and may have no fixed limits for their influence,

except for some parts of the system (inlet device surface, etc.) They can also be situated

inside small rooms, where walls, floors, and ceilings are the natural boundaries. The

systems usually consist of one exhaust hood and one supply inlet, which interact. There



are also special combinations, as two or more inlets and one exhaust hood, or one supply

inlet and two or more exhausts. All of these combinations need careful design and an

accurate relation between supply and exhaust flow rates and velocities. Some systems

also need stable temperature conditions to function properly. All combinations are

dependent on having a defined contaminant concentration in the inlet air. This usually

implies clean supply air, but some systems may use recirculated air with or without

cleaning.

There are many possible combinations of supply and exhaust air. For example, a line jet

could be used as a shield in an opening, as a stripping system on surfaces, for blowing

contaminants into an exhaust, etc. An enclosure could be designed with a line jet in the

opening, with a wall jet inside to increase efficiency, or with a low-momentum jet inside

or outside the opening to replace the room air supply. In this section, only some basic

combinations are described.

All rooms need both supply and exhaust air. The combined systems described in this

section are unique in that they must be chosen and designed simultaneously, since the aim

is to get a specific flow field—dependent on the exhaust and the supply simultaneously—

inside the specified volume. The flow rates are usually not the same in the supply and the

exhaust parts of the system. This means that the same flow difference must exist in the

room's ventilation system, if the combined system takes its air from outside the room and

disposes of the air to the same place. There is no general rule for how to choose between

the systems, except what has been specified for exhaust hoods and supply inlets,

respectively. Usually, the choice is made by tradition or the equipment available. This

should not prevent the designer from exploring the relative advantages and disadvantages

of these systems (which are described for each system) and applying and designing a

system that suits his or her demands for a specific process.

Similar to supply inlets, no measurements exist for evaluating the inlets' specific

influence on contaminant concentration. The available measurements for the

combinations are the same as for exhaust hoods, i.e., capture efficiencies and similar



measures. Sometimes the performance of a combined system can be approximated from

the performance of the incoming supply inlet and exhaust hood.

For a combined system it is always important to consider how the person working with a

process and the contaminant source are placed in relation to the inlet and outlet. Exactly

what their relative positions should be to get the highest efficiency depends on the

specific system. [13]

5.4.3 Air jets

Air jets are used for many purposes. Some of these are described in other parts of this

chapter, but it is not possible to describe all the possible types and uses. When jets are

used inside rooms, they do not need to have any corresponding exhaust air. Exhausted air

is needed for supply jets in general ventilation, but if the jet's air is taken from the room

and blown into the room again, no exhaust is need for supply jets in general ventilation,

but if the jet's air is taken from the room and blown into the room again, no exhaust is

needed. If the air is taken from the outside the room, it is necessary to the same flow rate

exhausted from the room. [13]

5.4.4 Cyclone filters:

Cyclone collectors are popularly used both for particle removal and for particle sampling.

The separation process of a cyclone relies on the centrifugal accelerations that are

produced when particle- laden fluid experiences a rapidly swirling motion in the cyclone.

The larger the particle, the stronger the centripetal acceleration it acquires and, therefore,

the easier it is for the particle to be collected. Figure5.6 is a schematic diagram of the

trajectories for small and large particles in a typical cyclone. A particle of small diameter

penetrates the cyclone, whereas a particle of large diameter finds its way to the side wall

of the cylindrical portion of the cyclone and is then collected at the apex of the cyclone

via the boundary layer flow.

The collection efficiency curve is usually employed to demonstrate the performance of a

cyclone. Figure 5.7 shows a typical collection efficiency curve for a cyclone at a

particular airflow rate. The size of particles that have a collection efficiency of 50% is

usually employed as a simple indication of the separation efficiency of the cyclone, and is



known as the cut-off particle size d<ft. Particles larger than the cut-off size d$Q are more

likely to be separated by the cyclone, and particles smaller than the cut-off size are more

likely to penetrate the cyclone.

Pressure loss through the cyclone is also a key performance parameter, and this depends

mainly on the design of the cyclone. In general, the pressure drop across the cyclone

collector is small compared with most other dust collectors, but the higher the collection

efficiency, the larger the pressure drop and hence the energy consumption required. [13]

Figure 5. 7 Schematic diagram of trajectories[13]

Figure 5. 8 collection efficiency curve of a cyclone[13]



5.5 Evaluation Phase

All the above principals were chosen for VE project because Envirotech had to come with

new concepts of exhaust ventilation hoods. A concept was generated based on the

proposed principles.



6 – Problem solving

6.1. Development Phase

After receiving the approval, actual work starts. It involves activities like using CAD

softwares, analysis tools, for concept generation, computational fluid dynamics analysis

and justification.

6.2 Concept generation

Figure 6. 1 capture jet exhaust hood

Figure 6.1 shows the capture jet exhaust hood concept generated in CATIA. The new

concept has addressed the issues faced by the older exhaust only hoods.

Fig 6.2 shows the parts of newly generated concept.

Figure 6. 2 capture jet exhaust hood concept



6.2 Working of Capture jet hood Concept

Figure 6. 3 Working of Capture jet exhaust hood concept

1 The kitchen hood above cooking appliances contains the rising warm air and

contaminants

2 The capture air jets direct the contaminated air toward the KSA grease filters

3 Where grease particles and other impurities are separated from the exhaust air using

the cyclone separation principle. The extracted grease and other air contaminants flow

into a drain channel and toward the collection tray.

4 Make up air is distributed into the space at low velocity through the front plenum of

the hood.

5 The vertical capture air improves efficiency, and allows the hood to operate at lower

exhaust airflows.



6 Capture Jet air is used to increase air velocity in the working zone near the cooking

equipment in order to compensate for the effects of radiant heat emitted by the

cooking equipment.

7 The Side Jets for enhanced performance.

6.3 Working of Cyclonic grease filter concept

Figure 6. 4 Working of Cyclonic grease filter concept

Figure 6.4 shows the working of the newly designed cyclonic grease filter. The working

is as follows:

1. Air enter through a slot in the filter face

2. Air spins through the filter, impinging grease on the filter walls.

3. The cleaner air exits the top and bottom of the filter.



7 – Results and Discussions

7.1. GEOMETRY MODEL

The fig: 7.1 show the simple hood model which has capture jet arrangement with

average mesh. In order to save the CFD computational time and cost, trivial geometric

details that are unimportant from fluid flow point of view, such as mounting bolts, blends,

stiffeners and steps have been ignored. Ignoring all the above-mentioned, so called a

cleaned geometry was obtained from CATIA. The fig: 7.2 show the normal exhaust

model.

Figure 7. 1 Capture jet hood model

Figure 7. 2 Normal exhaust hood model



Figure 7. 3 Filter in Capture jet

Figure 7. 4 Filter in Normal Exhaust Hood

7.1.1 CFD MESHING

To capture the three-dimensional flow inside the domain with reasonable accuracy,

one needs good quality mesh. Multi-block structured polygonal mesh was considered to

be the best for this case and was created using STAR CCM+. The model was

approximately 0.55 lacks polyhedral fluid elements. Figure (7.6) shows polyhedral mesh

of intake system fluid domain.



Figure 7. 5 Volume Tetrahedral mesh

Figure 7. 6 Volume Polyhedral Mesh

7.1.2 CFD MODEL DESCRIPTION

Air was used as fluid media, which was assumed to be steady and incompressible.

High Reynolds number k-ε turbulence model was used in the CFD model. This

turbulence model is widely used in industrial applications. The equations of mass and

momentum were solved using SIMPLE algorithm to get velocity and pressure in the fluid

domain. The assumption of an isotropic turbulence field used in this turbulence model



was valid for the current application. The near-wall cell thickness was calculated to

satisfy the logarithmic law of the wall boundary. Other fluid properties were taken as

constants. Filter media of intake system is modelled as porous media using coefficients.

In the porous region, the pressure drop per unit length can be determined using the

equation

p/L= –(Pi v + Pv)v

Where v is the superficial velocity through the medium and Pi, Pv are coefficients

defining the porous resistance, known as the inertial resistance and viscous resistance,

respectively. Values for the resistance coefficients can be measured experimentally or

derived using various empirical relationships, depending on the exact nature of the

problem. In this case, Pi = 2500kg/m4 and Pv = 3000 kg/m

3s.

These values are roughly what we would expect from an isotropic porous filter.

7.1.3. GOVERNING EQUATIONS

Commercial CFD solver Star-CCM+ was used for this study. It is a finite volume

approach based solver which is widely used in the industries. Governing equations solved

by the software for this study in tensor Cartesian form are following:

Continuity:

Momentum:

Where ρ is density, u

j is jth Cartesian velocity, p is static pressure, τ

ij is viscous stress tensor



7.1.4 BOUNDARY CONDITIONS

Various boundary conditions for the different components applied to this study were as

follows:

For inlet, four mass flow rates (0.5, 1, 3, 5 kg/s) were imposed using the fixed mass inlet

boundary condition. The value of density (1.2 kg/m3

), total pressure (1 atm) and

turbulence intensity (5%) were specified at the inlet boundary. For outlet, outflow

boundary condition was imposed with Pressure outlet (3bar). No slip boundary condition

was applied on all wall surfaces. For main filter media, porous media boundary was

imposed with pi = 2500 and p

v= 3000. Whole domain was considered at 1 atm and at 298

K as initial condition.

7.2 Results and discussions:

Velocity vector plot of Capture jet model:-

Figure 7. 7 Velocity at outlet section



Figure 7. 8 Velocity at inlet section (circulations @inlet)

The above fig shows the velocity vector plot at outlet section. Velocities are high in

Capture jet model because of extra jet of air. Due to high velocity there are large

recirculation zones forming at inlet section also which intern increases the mixing and

filtration of exhaust gases. The average velocity at outlet is high compared to standard

model.

Figure 7.9 shows the velocity vector plot of Normal exhaust model:

Figure 7. 9 velocity vector plot



Due to direct placing of filter in hood leads to less capturing efficiency and due to lack of

driving force the velocities are pretty low. Hot gases remain in the kitchen.

Figure 7. 10 Pressure contour of Whole hood

Figure 7. 11 Pressure contour of filter



Figure 7.10 shows the Pressure Contours of Capture jet model. Figure 7.11 shows the

Pressure Contours of cyclonic filter. Due to lot of restriction to air flow in the Capture jet

model in the form of filter material and small passages lot pressure is dropping in the

Capture jet model. The above pressure contour indicates the lot of pressure variations, the

red regions are high pressure regions. It can be observed mainly on filter core. Due to this

high pressure drops we need to have fans and blowers to drive the air.

Figure 7. 12 Pressure contour of exhaust section

Figure 7. 13 Pressure contour of intake section



Figure 7.14 shows the Pressure Contours of exhaust hood model. Figure 7.15 shows the

pressure contour of section.

Figure 7. 14 Pressure contour of hood

Figure 7. 15 Pressure contour of section



It is observed that the pressure variation is very less in standard model when compared to

capture jet model. Due to less pressure drop across the hood, it is not required to install

Fans and blowers.

Figure 7.16 shows the Temperature Contours of section of Capture Jet model.

Figure 7. 16 Temperature contour of section

Figure 7. 17 Vortices contours



Due to high velocity and high turbalance lot of energy transaction will be happen between

molcuels of the air, which intern increases the heat carring capacity of jet air. It is

observed that exahust temperature of air in the capture is more when compared to

standard exhaust model. The main purpose of these kitchen hoods are to carry away the

heat generated in the kitchen and to filter the air which is going out. Figure 7.18 shows

the Temperature Contours of exhaust only hood model.

Figure 7. 18 Temperature contour of exhaust section



Figure 7. 19 Conduction heat flux contours

7.2.1 Residual plot:

Figure 7. 20 Residual plot of Capture jet model



The above diagram (Figure 7.20) shows the convergence history of Capture jet

model.It took around five itteration to converge.The convergence criteria is taken around

1e-5. Lot of up and downs shows the fluctuating flow in the capture jet.

Figure 7. 21 Residual plot of Exhaust hood model

The above diagram (figure 7.21) shows the convergence history of Capture jet

model.It took around five itteration to converge.The coonvergence criteria is taken around

1e-6. There is no much flctuvations in residuals, which indicates smooth flow in standard

exhaust model.



7.2.2 Capture efficiency vs. inlet airflow:

Figure 7. 22 Capture efficiency vs. inlet airflow

The above plot (figure 7.22) shows the Capturing efficiency of both type of hood

with respect to different flow conditions. It show clearly that for same flow rate capture

jet efficiency is more efficient than the standard exhaust model.

7.2.2 Heat gain vs. air flow:

The below plot (figure 7.23) shows the heat gain by the air from the hot gases

delivered in kitchen. As we saw the large differences in the exhaust temperatures of both

type of hoods. For same mass flow rate more heat is gained in the capture jet exhaust

hood.



Figure 7. 23 heat gain vs. air flow



8 - Conclusions

8.1 Conclusion

Displacement ventilation flow systems have become increasingly popular and are

replacing the traditional mixing ventilation systems, it is of great interest to carry out

numerical investigation of the flow. In mixing ventilation, fresh air is supplied at high

velocity (momentum), inducing an overall recirculation in the room, which gives an

efficient mixing. In this way the polluted air is diluted in an efficient way. In

displacement ventilation, however, the objective is to keep the fresh and polluted air

separated

A new island model hood was designed using various ventilation principles such as

displacement ventilation, capture jets and cyclonic grease filters. A CFD analysis was

carried out to compare the capture and containment efficiencies of the old exhaust only

hood and the newly developed capture jet hood concept. The results are as follows:

From the results of this analysis Capture jet hood is up to 50% more efficient than

normal exhaust hood model in capturing the effluence.

Heat gain from the exhaust gases is more in capture jet model compared to exhaust

hood model, because of more air inlet and more turbulence inside the hood.

Use of high-velocity Capture Jets increases the face velocity of the hood with lower

air flow.

Efficiency is higher and air flow rates are 30% lower than those of an exhaust-only

hood system. The need for replacement air is reduced as well.

Capture Jets maintain efficient exhaust despite turbulence and prevent excess heat and

impurities from spreading to the occupied zone. They also improve hygiene.

The Capture Jets cool the hood unit and reduce radiant heat.



8.2 Recommendations

The application of CFD modelling is a very promising tool, and its use can be very

helpful in a large number of applications but also requires some experience of the CFD

engineer to produce accurate results.

Usually, quite a number of parameter variations are needed, and different levels of

simplification of the real situation have to be applied at different stages of the design

process to draw the desired conclusions.

It is greatly recommended that strong feedback between the designer who needs the

results and the CFD engineer is maintained to improve the results.

CFD results can only be as good as:

1. Quality of geometric modelling and spatial resolution of computational mesh

2. Models involved in CFD code

3. Knowledge of boundary conditions [13]

This is not as simple as it sounds, as the boundary conditions are very often not well

known. The number and distribution of heat sources and ventilation parameters,

particularly in naturally ventilated surroundings, are very often not known or even vary.

The CFD engineer has to cope with this situation and can do one of the following:

Choose boundary conditions from his or her knowledge about the given

information.

Perform calculations with parameters varied to check their importance.

The CFD results can possibly turn out to be helpful more comparatively (qualitatively)

than quantitatively.



References

[1] Mark A.Vonderembse et.al, ―Qualifying function deployment’s impact on product

development‖, International Journal of Quality Science, Vol.2 no.4, 1997, pp.253-271.

[2] Lin Chih Cheng, ―QFD in product development: methodological characteristics and a

guide for intervention‖, International Journal of Quality & Reliability management,

Vol.20 no.1, 2003, pp 107-122.

[3] James R.Wixson, ―Improving product development with value analysis/ value

engineering: A total management tool‖, SAVE conference proceedings, 1987, pp51-66.

[4] Biren Prasad, ―Synthesis of market research data through a combined effort of QFD,

value engineering and value graph techniques‖, Qualitative Market research: An

International Journal, Vol.1 no.3, 1998, pp156-172.

[5] Fabio et.al, ―Combined application of QFD & VA tools in the product design

process‖, International Journal of Quality & Reliability Mgmt, Vol.21 No.2, 2004, pp231-

252.

[6] ―Design Guide: Improving Commercial Kitchen Ventilation system performance‖,

California Energy commission P-500-03-034F Rev.5.5.03, 2002.

[7] ASHARE, ―ASHRAE HVAC Applications Handbook – Chapter 31, Kitchen

Ventilation”, American Society of Heating, Refrigerating and Air-Conditioning

Engineers, 2007

[8] Andrey et.al, ―The effect of supply air systems on kitchen thermal environment‖,

ASHARE transactions: Symposia, Vol 111, Part 1, pp 748-754, 2005.

[9] Risto et.al, ―The influence of a capture jet on the efficiency of a ventilated ceiling in a

commercial kitchen‖, International Journal of Ventilation, Volume1, No.3, pp 189-199,

2003.

[10] Risto et.al, ―Analysis of capture and containment efficiency of a ventilated ceiling‖,

International Journal of Ventilation, Volume2, No.1, pp 33-43, 2003.



[11] Dr.Kai yang, ―Voice of the Customer Capture and analysis‖, Mc-Graw hill

publishers, 2008.

[12] Abdul Naser Sayma, ―Computational Fluid Dynamics‖, Ventus publishing Aps,

2009.

[13] Howard et.al, ―Industrial Ventilation Design guidebook‖, Academic press, 2001.

Application of QFD and Value Engineering Concepts in Product Development of Commercial Ventilation System Exhaust Hood

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