Project Report on analysis of a solar heter by Ansys.

A Project Report On

Thermal Analysis of Solar Air Heater using CFD as a tool Submitted by

Chandan Kumar Chhangani (12EMTME027)

Department of Mechanical Engineering Maharishi Arvind Institute of Engineering and Technology, Jaipur Sector-7, Madhyam Marg, Mansarovar, Jaipur, Rajasthan, India-302020

Rajasthan Technical University, Kota May 2016

Thermal Analysis of Solar Air Heater using CFD as a tool  A

P r oj ect R epor t Submitted in partial fulfillment for the award of the Degree of

B achelo chelorr of T echnology chnology In

D epar tment Me M echani chanica call E ng ngii nee neer i ng

Supervisor

Submitted By:

Mr. Ankur Singh

Chandan Kumar Chhangani

Asst. Professor

(12EMTME027)

Department of Mechanical Engineering

Maharishi Arvind

Institute of Engineering and Technology, Jaipur Sector-7, Madhyam Marg, Mansarovar, Jaipur, Rajasthan, India-302020

Rajasthan Technical University, Kota March 2016

Thermal Analysis of Solar Air Heater using CFD as a tool  A

P r oj ect R epor t Submitted in partial fulfillment for the award of the Degree of

B achelo chelorr of T echnology chnology In

D epar tment Me M echani chanica call E ng ngii nee neer i ng

Supervisor

Submitted By:

Mr. Ankur Singh

Chandan Kumar Chhangani

Asst. Professor

(12EMTME027)

Department of Mechanical Engineering

Maharishi Arvind

Institute of Engineering and Technology, Jaipur Sector-7, Madhyam Marg, Mansarovar, Jaipur, Rajasthan, India-302020

Rajasthan Technical University, Kota March 2016

Candidate’s Candidate’s Declaration I hereby declare that the work, which is being presented in the Major Project entitled “Thermal Analysis of Solar Air Heater using CFD as a tool” in partial fulfilment for the award of Degree of “ Bachelor  of Technology” in Dep t. of Mechanical Engineering and submitted to the Department of Mechanical Engineering, Maharishi Arvind institute of Engineering & Technology, Rajasthan Technical University is a record of my own investigations carried under the Guidance of Mr. Ankur Singh., Department of Mechanical Engineering, Maharishi Arvind institute of Engineering & Technology . I have not submitted the matter presented in this report anywhere for the award of any other Degree.

(Chandan kumar chhangani)

Roll No.: 12EMTME027 Maharishi Arvind institute of Engineering & Technology , Counter Signed by

Supervisor Ankur Singh

CERTIFICATE

This is to certify that Chandan Kumar Chhangani of VIII Semester, B.Tech (Mechanical Engineering) 2015-16, has presented a major project titled “Thermal Analysis of Solar Air Heater using CFD as a tool ” in partial fulfilment for the award of the degree of Bachelor of

Technology under Rajasthan Technical University, Kota.

Date:

Ankur Singh Project Coordinator

Ankur Singh Supervisor

R.P. Choudhary H.O.D

ACKNOWLEDGMENET

I take this opportunity to express my gratitude to all those people who have been directly and indirectly with me during the competition of this project. I pay thank to Ankur Singh  who has given guidance and a light to me during this major  project. His versatile knowledge about “Thermal Analysis of Solar Air Heater using CFD as a tool” has eased me in the critical times during the span of this major project.

I acknowledge here out debt to those who contributed significantly to one or more steps. I take full responsibility for any remaining sins of omission and commission.

Chandan Kumar Chhangani B.Tech IV Year (Mechanical Engineering)

ABSTRACT Solar air heating is a solar thermal technology in which the energy from the sun is captured by an absorbing medium and used to heat air. Solar air heater including a housing having a transparent front wall and an inlet and outlet for establishing a flow path for a gas such as air to be heated. An attempt has been made to carry out CFD based analysis using FLUENT to fluid flow and heat transfer characteristics of solar air heater. 3D model of the Solar Air heater involving air inlet, absorber plate, glass, modeled by ANSYS Workbench and the unstructured grid was created in ANSYS. The results were obtained by using ANSYS  FLUENT software. This work is done by using computational fluid dynamics (CFD) tool with respect to flow and temperature distribution inside the solar air heater .

CONTENTS Certificate ..................................................................................................................................i Acknowledgement.................................................................................................................... ii Abstract.................................................................................................................................... iii List of Figures …...................................................................................................................... List of Tables …....................................................................................................................... Chapter 1: Introduction … ........................................................................................................1 1.1 History of Solar heating ….................................................................................................1 1.2 Solar energy……………………………………………………………………………....2 1.3 Solar air heater……………………………………………………………………………5 1.4 Types of solar air heater…………………………………………………….………...….7 1.5 Thermal conditions used f or solar air heater……………………………….………….....8 1.6 Work Objectives…………………………………………………………….…………....9 Chapter 2: Literature review………………………………………………………………....10 Chapter 3: Research methodology…………………………………………………………...18 Chapter 4: Materials and methodology……………………………………………………....22 4.1 Materials used for thermal analysis……………………………………………………...22 4.2 Modeling and designing tool…………………………………………………………… .25 4.3 Discretization method……………………………………………………….…………...28 4.4 Thermal analysis tool……………………………………………………….…………....32 4.5 Components of solar air heater……………………………………………………….….35 Chapter 5: Analysis of solar air heater……………………………………………… .……...36 5.1 Analysis tools…………………………………………………………………….……...36 5.2 Environmental conditions………………………………………………………………. .44 5.3 Boundary conditions……………………………………………………………………..45 Chapter 6: Result…………………………………………………………………………….46 Chapter 7: Applications……………………………………………………………………...47 Chapter 8: Conclusion……………………………………………………………………….49 Chapter 9: Future scope……………………………………………………………………...50

LIST OF FIGURES Fig. 1.1 Grid tied solar electric syatem………. .....................................................................................3 Fig. 1.2 Solar air heating…....................................................................................................................4

Fig. 1.3 Solar air heater ….....................................................................................................................6 Fig. 1.4 Transpired solar collector…………………………………………………………………….7 Fig. 3.1 Types of analysis……………………………………………………………………………..21 Fig. 4.1 Aluminum…………………………………………………………………………………….23 Fig. 4.2 Glass………………………………………………………………………………………….24

Fig. 4.3 Product designed in CREO…………………………………………………………………..26 Fig. 4.4 Structure designed in Autodesk inventor…………………………………………………….27 Fig. 4.5 Meshing………………………………………………………………………………………30 Fig. 4.6 FEM mesh refinement………………………………………………………………………..31

Fig. 4.7 CFD analysis…………………………………………………………………………………34 Fig. 5.1 Ansys…………………………………………………………………………………………36

Fig. 5.2 Complex model in Ansys….....................................................................................................37 Fig. 5.3 Design 1: Plain surface…........................................................................................................39 Fig. 5.4 Design 2: Normal zig zag surface……………………………………………………………39 Fig. 5.5 Design 3: Inclined zig zag surface…………………………………………………………...40

Fig. 5.6 Result 1: Plain surface……………………………………………………………………….42 Fig. 5.7 Result 2: Normal zig zag surface…………………………………………………………….42 Fig. 5.8 Result 3: Inclined zig zag surface……………………………………………………………43 Fig. 5.9 Radiation……………………………………………………………………………………..45

Fig. 6.1 Result………………………………………………………………………………………...46 Fig. 7.1 Solar air heating connected to the make-up air unit…………………………………………47 Fig. 7.2 Solar air heating in parallel with the make-up air unit………………………………………48 Fig. 7.3 Solar air heating within loop of roof-top unit………………………………………………..48

LIST OF TABLES Table 3.1 Materials used …..................................................................................................................20

Chapter 1 INTERODUCTION

Solar air heating is a solar thermal technology in which the energy from the sun, insolation, is captured by an absorbing medium and used to heat air. Solar air heating is a renewable energy heating technology used to heat or condition air for buildings or process heat applications. It is typically the most cost-effective out of all the solar technologies, especially in commercial and industrial applications, and it addresses the largest usage of building energy in heating climates, which is space heating and industrial process heating.

1.1 History of Air Heating For the first 100 years home heating was dominated by biomass (wood) and it was not until 1885 that the nation would burn more coal than wood. Prior to 1885 the majority of homes were heated with wood burning brick fireplaces and derivatives of the cast iron Franklin stove invented in 1742. By the end of the 19th century the invention of low cost cast iron radiators would bring central heating to homes with a coal fired boiler in the basement delivering hot water or steam to radiators in every room. At about the same time, in 1885, Dave Lennox built and mark eting the industry’s first riveted-steel coal furnace. Without electricity and fans to move air, these early furnaces transported heat by natural convection (warm heated air rising) through ducts from the basement furnace to the rooms above. These two methods would dominate home central heating until 1935, when the introduction of the first forced air furnace using coal as a heat source used the power of an electric fan to distribute the heated air through ductwork within the home. Shortly thereafter, gas and oil fired versions of forced air furnaces would relieve the homeowners from the chore of “stoking the coal fire” and relegate coal furnaces and cast iron radiators to the dust bin of history. Fast forward to today and about 60% of our homes be heated with gas fired forced air furnaces (FAU’s) and another 9% with oil fired FAU’s. In warmer climates, a quarter of our homes would be heated by FAU’s using electric “heat  pumps” to supply heating energy. Modern Beginnings: Chimneys and Stoves:The next important advance in heating was the invention of the chimney. The origins of the chimney flue probably lie with the Normans, who used sidewall flue openings in place of the  previously used central roof vents. Many sidewall flues were constructed at an oblique angle upward, thus beginning a transition to vertical chimney construction. After the 14th century, chimneys appear in written literature. However, their use seems to have spread very slowly. Chimneys were still rare enough 200 years later that one

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Early chimneys were very large, so as to allow a chimney sweep to climb into them. But the size precipitated such vicious drafts that room divider screens sometimes had to be used to shield the occupants. Stove heating soon advanced beyond the crude devices first used. The first freestanding warm-air stove was probably the “Furnus Acapnos” or “smokeless stove” invented by Dalesme in France in the late 1600s. Dalesme introduced fresh fuel in the same opening as combustion air, directing all combustion products over already-burning fuel, a design that ensured complete combustion. Although the smokeless stove was a great advance, it and other heating innovations were accepted slowly, for “…few housekeepers are philosophers enough to be willing to undertake the management of a machine requiring especial mental effort, where the advantages are not directly visible to the senses.” The earliest stove in North America was probably a cast iron box stove invented by Dr. John Clarke of the Massachusetts Bay Colony about 1652. This type of stove had originated in Holland and was imported into England after 1600. By the mid-1700s, cast iron box stoves were being manufactured by a number of eastern Colonial American foundries. Stoves continued evolving throughout the 1800s. Notable improvements included the base  burner stove invented by Eliphalet Knott in 1833, and the airtight stove invented by Isaac Orr in 1836. A stove with thermostatic draft control was invented by F.P. Oliver in 1849. By the time of the Civil War, cast iron stove manufacturing was a large and well-established industry, particularly in the north-eastern U.S. By 1900, thousands of different designs (many approaching pieces of art in their appearance) were produced by dozens of manufacturers.

1.2 Solar Energy Solar energy is the most readily available source of energy. It does not belong to anybody and is, therefore, free. It is also the most important of the non-conventional sources of energy  because it is non-polluting and, therefore, helps in lessening the greenhouse effect. Solar energy has been used since prehistoric times, but in a most primitive manner. Before 1970, some research and development was carried out in a few countries to exploit solar energy more efficiently, but most of this work remained mainly academic. After the dramatic rise in oil prices in the 1970s, several countries began to formulate extensive research and development programmes to exploit solar energy.

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When we hang out our clothes to dry in the sun, we use the energy of the sun. In the same way, solar panels absorb the energy of the sun to provide heat for cooking and for heating water. Such systems are available in the market and are being used in homes and factories.

Fig. 1.1 In the next few years it is expected that millions of households in the world will be using solar energy as the trends in USA and Japan show. In India too, the Indian Renewable Energy Development Agency and the Ministry of Non-Conventional Energy Sources are formulating a programme to have solar energy in more than a million households in the next few years. However, the people’s initiative is essential if the programme is to be successful. India is one of the few countries with long days and plenty of sunshine, especially in the Thar Desert region. This zone, having abundant solar energy available, is suitable for harnessing solar energy for a number of applications. In areas with similar intensity of solar radiation, solar energy could be easily harnessed. Solar thermal energy is being used in India for heating water for both industrial and domestic purposes. A 140 MW integrated solar power  plant is to be set up in Jodhpur but the initial expense incurred is still very high. Solar energy can also be used to meet our electricity requirements. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly. This electricity can either be used as it is or can be stored in the battery. This stored electrical energy then can be used at night. SPV can be used for a number of applications such as:

a.  b. c. d. e.

Domestic lighting street lighting village electrification water pumping desalination of salty water 3

f.  powering of remote telecommunication repeater stations g. Railway signals.

Fig. 1.2 Solar air heating

Challenges and opportunities

Land is a scarce resource in India and per capita land availability is low. Dedication of land area for exclusive installation of solar arrays might have to compete with other necessities that require land. The amount of land required for utility-scale solar power plants —   currently approximately 1 km2  (250 acres) for every 40 – 60 MW generated  —   may pose a strain on India's available land resource. One alternative is to use the water surface area available on canals,  lakes, reservoirs and sea for locating large capacity solar power plants. These water  bodies can also provide the water needed for periodic cleaning of the solar panels. It is also  possible to use the high ways and rail tracks to avoid excessive cost of land nearer to load centres and minimise transmission lines cost by installing solar power plants at nearly 10 meters height above the roads or rail tracks. It would also protect the high ways from damage from rain & intense summer heat and offer additional comfort to the commuters. The architecture more suitable for most of India would be a highly distributed set of individual rooftop power generation systems, all connected via a local grid. However, erecting such an infrastructure, which does not enjoy the economies of scale possible in mass, utility-scale, solar panel deployment, needs the market price of solar technology deployment to substantially decline, so that it attracts the individual and average family size household consumer. That might be possible in the future, because PV is projected to continue its 4

current cost reductions and be able to compete with fossil fuel. In the year 2015, the levelized tariff in US$ for solar electricity using thin film technology based solar PV modules has fallen below 4 cents/kWh which is far cheaper than the electricity sale price from coal based electricity generation plants in India.Indian government has recently reduced the solar power  purchase price from maximum allowed levelized tariff of 5.79 Rs/KWh to 4.43 Rs/KWh in view of steep fall in the cost of the solar power generation equipment. The applicable tariff is after allowing either viability gap funding (VGF) or accelerated depreciation (AD) incentives. It is prudent to encourage solar power plants installation up to a threshold limit (say 7,000 MW) by giving direct or indirect incentives. Otherwise, dubious short sighted financial operators from all over the world would take over the industry to encash the liberal Indian  bank loans offered by installing substandard and shorter life solar power plant equipment with over rated nameplate capacity .The solar power purchaser (DisComs, etc.), solar power transmission agency (TransCos) and the Indian financial institutions should insist for annual  penalty payment from IPPs for not meeting minimum guaranteed capacity utilisation and long term performance guarantee for the equipment backed by insurance coverage to ensure that the guarantee works even after the OEM becomes bankrupt.

1.3 Solar Air Heater Solar air heaters are systems that collect solar energy and transfers the heat to passing air, which is either stored or used for space heating. The collectors are often black to absorb more of the sun's energy and a conductive material, often metal, acts as a heat exchanger. There are many different designs and systems may include fans to increase the flow rate of air. Alternatively, a passive collector can be built such that when the hot air rises it draws fresh air through the bottom. Fans can often increase the performance of the system, but require additional parts and adds complexity. Solar air heaters can compliment traditional indoor heating systems by providing a free and clean source of heat (after initial costs). While clouds effect the energy output of the system, the metal will store energy on a hot day and will reduce the impact of momentary cloud cover. To achieve best results, the system should be unshaded and facing the general direction of the sun (south for the northern hemisphere, north for the southern hemisphere). More than any other solar technology, solar heaters are DIY-friendly, since they require only a basic knowledge of carpentry and electrical skills, can be made of easy-to-find materials, and can be installed on a south-facing wall rather than on a potentially dangerous roof. Solar air heaters are tolerant of less-than-exact construction details. A small air leak will only reduce the heater’s overall efficiency, not leak fluid or potentially overheat or shock you if installed improperly. While care should be taken with any project, the consequences of  potential mistakes are much less dire. For homeowners interested in the basics of renewable energy, building a solar air heater can be a great project.

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Solar Air Heater

Fig. 1.3 Considerations Before beginning, it’s important to have access to the sun where and when you need it or all of your hard work will be for naught. Make sure there is full sunlight on the south-facing wall in the winter months from about 10 a.m. to 2 p.m. The sun is at a low angle during the winter, so the number of potential obstructions increases. If you can’t accurately assess the winter solar window within a few weeks of the winter solstice, use a solar analysis instrument such as a Solar Pathfinder or Sol metric’s Sun Eye. DIY solar heaters should be installed on south-facing walls and never on roofs. Homemade heaters tend to fare poorly in the extreme weather conditions that exist on roofs, and the  produced heat tends to stay at the ceiling level. Hot air is likely to stratify into layers and stay stuck away from where residents want it — near the floor. Using a stronger blower might seem like it would solve this problem and help circulate the air, but it risks moving the air through the heater too quickly before it has time to heat up, and quickly moving air, regardless of temperature, has the effect of cooling the skin and making a room feel draft. Design Types

A solar air heater is basically a glazed, insulated black box with two vents. This simplicity allows a great variety of potential designs. Primary concerns are the design’s efficiency, construction ease, and cost —and there’s some trade-off between these goals. I decided on a simple design that blows air between a black metal absorber plate and polycarbonate glazing. A fan moves the air from the bottom of the collector to the top, transferring heat from the absorber to the air. Because this design uses a fan, it is an active solar air heater   — there are moving parts that require electricity. A passive solar air heater moves air by convection only — as the air inside a passive heater warms, it expands and becomes lighter, moving upward until an unassisted flow called a thermosiphon develops. Active heaters are roughly 200% more efficient than 6

 passive heaters, but with additional complexity and cost. Passive heaters tend to become overheated and reradiate much of the heat trapped in the collector back to the outside before it warms the air flowing through into the building. Besides the difference between active and passive, there are four heater design considerations  based on time, skill level, and available materials. The one we built is an empty box collector   — air is heated by passing through an empty glazed box facing the sun.

1.4 Types of Solar Air Heater 

Unglazed solar collectors, Transpired air systems: Unglazed solar collectors are primarily used to ambient air and not building air. These are low cost collectors and these require only one penetration into the building, or if existing fan inlets are used, then no additional penetrations are necessary. The transpired air collectors are generally wall mounted to capture the lower sun angles in the winter months, additional sun reflection off the snow and they also capture heat loss escaping from the building envelop which is collected in the solar wall air cavity and drawn back in to the ventilation system.

Fig. 1.4 Transpired Solar Collector 



Glazed solar collectors: Glazed solar collectors are designed primarily for space heating and they recirculate  building air through a solar air panel where the air is heated and then directed back into the building. These solar space heating systems require at least two penetrations into the building and only perform when the air in the solar collector is warmer than the building room temperature. Most glazed collectors are used in the residential sector and thus will be dealt with at a later time. Glazed air collectors heat air through circulation. A fan moves cold air from the home to the collector. After passing through the collector, the heated air is ducted back to

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the home. There are multiple system designs: Through pass, back, front and combination passage. 



Hot Air Collectors Hot Air solar collectors can be used to supplement the heating requirements of a house in a cold climate. As long as the house is well insulated and one side of the house has adequate sunlight exposure a homemade solar hot air heating system could  be a good investment. The price of oil will continue to rise, but the wise use of sunlight energy may be used to reduce the consumption fossil fuel concentrates. Hydronic solar collectors have the advantage of supplying heat and hot water all year long, but the simplicity of hot air collectors has a special appeal to home owners with limited time for projects. Hot air collectors do not require storage tanks to store heat or radiant floors to distribute heat. Instead household furnishings and interior walls are used to store daytime solar heat and release it gradually at night. Aluminium Flashing Collector Aluminium flashing collector. Notice how the aluminium is bent like an accordion. This is done to increase the surface area of the aluminium in contact with the air that's  blown through it. Aluminium soffits and aluminium screens may also be used to transform light into heat.

1.5 Thermal Conditions Use for Solar Air Heater The energy demand is growing continuously and rapidly, and it is impossible to meet the future demand with the presently available exhaustible energy sources. So, the technology is focusing on harnessing new and renewable sources of energy. Furthermore, the conventional energy sources are causing an alarming health hazard to the planet life. The use of solar energy is an intelligent option for the use of mankind which is available free of cost, in abundant and is a clean source for various applications. The solar energy can be used directly or indirectly by converting it into thermal energy. Instead of direct use of solar energy, it is more useful when converted into thermal energy. Solar air heater is such a device, which converts solar energy into thermal energy. Solar energy collectors are a special kind of heat exchangers that transform solar radiation energy to internal energy of the transport medium. The major component of any solar heating system is the flat-plate solar collectors. This device absorbs the incoming solar radiation and converts it into heat and also transfers this heat to a fluid flowing through the collector. These conversions depend on the absolute performance of different materials such as glazing materials, collector absorbing plates and flowing fluid. The basic parameter to consider is the solar collector thermal efficiency. This is defined as the ratio of the useful energy delivered and the energy incident on the collector aperture. The definitions of various relations that are 8

required in order to determine the useful energy collected and the interaction of the various constructional parameters on the performance of a solar collector are fairly complex. Therefore, this paper proposes to study the use of ANN model to study the performance of SAH. Solar air heaters (SAH) have low thermal efficiency because of low convective heat transfer coefficient between the air and absorber plate which leads higher temperature to the absorber  plate causing maximum thermal losses to ambient. Artificial roughness or various arrangements created in the flow duct created turbulence near the collector wall or broke the  boundary layer. Thus, the various arrangement in flow duct can be operated for the enhancement of heat transfer coefficient between the absorber plate and air and thereby improving the thermal performance of SAH. Increasing the area of the absorber plate and varying the shape of the plate area will increase the heat transfer rate to the flowing air, ultimately on the other hand, will increase the pressure drop in the collector. This increases the required power consumption to pump the air flow crossing the collector. Several configurations of SAHs have been developed in literature for various designs with different shapes and dimensions of the air flow passage in plate type solar air collector were tested. Suitable sizing of the component of a solar system is a complicated problem which includes  both predictable and unpredictable components. For estimation of the flow of energy and the  performance of system, analytic computer codes are often used. The softwares employed are commonly complicated, involving the solution of complex differential equations. Instead of complex rules and mathematical routines, artificial intelligent methods are used to learn the key information pattern within a multidimensional information domain. From the last two decades, the use of artificial neural network methods in mechanical engineering has been increasing gradually. This is mainly because of the effectiveness of artificial intelligence modelling systems improved to a great extent in the engineering area. Forecasting of  performance is important in many air-conditioning and solar applications. This paper describes the applicability of ANN to predict the efficiency and temperature leaving the collector unit of a SAH system with different thermal storage materials. For this purpose, an experimental SAH system was set up and tested on bright as well as cloudy day conditions. The data used were measured on an hourly basis using temperature sensor, which was located in different location in the absorber plates, entry and exit of the SAH and are shown in the Figure.

1.6 Work Objectives 

Design improvement



Improve temperature of air 



Pollution free environment



Improve efficiencies



Eco-friendly 9

Chapter 2 LITERATURE REVIEW 1. Samir A. Dhatkar et.al. [1999], Solar air heater is one of the valuable heat sources with variety of applications such as space heating and cooling, industrial process heating and drying of fruits and vegetables etc. The major heat losses from a normal solar air collector are through the top cover which reduce the thermal efficiency also, the low heat transfer coefficient between the air stream and the absorber plate is another reason of low thermal efficiency in solar air heaters. Thermal efficiency of double pass solar air heater with porous media is higher than single pass and double pass solar air heater without porous media. Many experiments have been carried out on the performance analysis of double pass solar air heater with porous media and solar air heater with extended surfaces. Effect of various parameters of porous media like pitch, number of layers , bed depth,  porosity, thermal conductivity, pitch to wire diameter ratio have been studied. Also these studies includes the design of double pass solar air heater, heat transfer enhancement,  pressure drop, type of flow. It is found that more increase in thermal efficiency in comparison with conventional solar air heater. Based on literature review, it is concluded that most of the studies carried out on solar air heater with porous media and extended surfaces. Few studies are carried out on corrugated absorber plate. Improvement of thermal efficiency of solar air heater is to be obtained by enhancing the rate of heat transfer.

2. Raheleh Nowzaria et.al. [2008], the double pass solar air heater is constructed and tested for thermal efficiency at a geographic location of Cyprus in the city Famagusta. The absorber plate was replaced by fourteen steel wire mesh layers, 0.2 × 0.2 cm in cross section opening, and they were fixed in the duct parallel to the glazing. The distance  between each set of wire mesh layers is 0.5cm to reduce the pressure drop. The wire mesh layers were painted with black before installing them into the collector. The obtained results show that as the mass flow rate increases, the efficiency of the system also increases. The temperature difference (ΔT) between the inlet and outlet air through the system increases as the mass flow rate decreases. The maximum ΔT (53°C) is achieved at the flow rate of 0.011 kg/s. The range of the mass flow rate used in this work is between 0.011 and 0.037 kg/s. It is also found that the average efficiency obtained for the double  pass air collector is 53.7% for the mass flow rate of 0.037 kg/s.

3. Anil Singh Yadav et.al. [2006], this paper presents the study of heat transfer in a rectangular duct of a solar air heater having triangular rib roughness on the absorber  plate by using Computational Fluid Dynamics (CFD). The effect of Reynolds number on  Nusselt number was investigated. The computations based on the finite volume method with the SIMPLE algorithm have been conducted for the air flow in terms of Reynolds numbers ranging from 3000-18000. A commercial finite volume package ANSYS FLUENT 12.1 is used to analyse and visualize the nature of the flow across the duct of a 10

solar air heater. CFD simulation results were found to be in good agreement with experimental results and with the standard theoretical approaches. It has been found that the Nusselt number increases with increase in Reynolds number.

4. Hikmet Esen et.al . [1997], this paper presents an experimental energy and exergy analysis for a novel flat plate solar air heater (SAH) with several obstacles and without obstacles. For increasing the available heat-transfer area may be achieved if air is flowing simultaneously and separately overland under the different obstacle absorbing plates, instead of only flowing either over or under the different obstacle absorbing plates, leading to improved collector efficiency. The measured parameters were the inlet and outlet temperatures, the absorbing plate temperatures, the ambient temperature, and the solar radiation. Further, the measurements were performed at different values of mass flow rate of air and different levels of absorbing plates in flow channel duct. After the analysis of the results, the optimal value of efficiency is middle level of absorbing plate in flow channel duct for all operating conditions and the double-flow collector supplied with obstacles appears significantly better than that without obstacles. At the end of this study, the exergy relations are delivered for different SAHs. The results show that the largest irreversibility is occurring at the flat plate (without obstacles) collector in which collector  efficiency is smallest

5. Gurpreet Singh et.al. [2000],

An experimental investigation of the effect of geometrical parameters of circular transverse ribs on heat transfer of rectangular duct with heated plate having rib roughness on its underside have been reported. The range of   parameters for this study has been decided on the basis of practical considerations of the system and operating conditions of solar air heaters. The experimental investigation encompassed the Reynolds number (Re) range from 2564 to 6206; relative roughness  pitch (P / e ) of 8, angle of attack (α) of 90° and relative roughness height (e/Dh) is0.047. The thermal efficiency of roughened duct is observed to be 5%-9% more as compare to the smooth duct. The thermal efficiency is increased with increasing the value of Reynolds number 

6. Dharam Singh et.al.[2005], Solar air heater is solar energy collection devices and this collected solar energy is used for low temperature heating purpose, agriculture drying purpose etc. The heat conversion rate of solar energy to heat energy is low in solar air heater because air is flowing fluids and air has low heat transfer coefficient, which is directly influence the rate of heat transfer from the absorber plate to air. This fluid  property heat transfer coefficient can be increase by creating turbulence in flow field and the turbulence is created by providing different shape artificial roughness on absorber  plate. In this paper the study of heat transfer in a rectangular duct of a solar air heater having trapezoidal rib roughness on the absorber plate is done by using Computational Fluid Dynamics (CFD). The effect on Nusselt number, heat transfer coefficient, velocity, and temperature parameter are analysed .This CFD simulation is done by fluent 6.3 software using K-ε model

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7. Mokalla Srinivas et.al. [1998], A solar hybrid energy system having photovoltaic and thermal (PV/T) devices, which produces both thermal and electrical energies simultaneously is considered for analysis. A double pass hybrid solar air (PV/T) heater with slats is designed and fabricated to study its thermal and electrical performance. Air as a heat removing fluid is made to flow through upper and lower channels of the collector. The collector is designed in such way that the absorber plate is partially covered by solar cells. The raise in temperature of the solar cell is expected to decrease its electrical  performance. Thin metallic strips called slats are attached longitudinally at the bottom side of the absorber plate to improve the system performance by increasing the cooling rate of the absorber plate. Thermal and electrical  performances of the whole system at varying cooling conditions are also presented.

8. Rewaram Verma et.al. [2004], Improvement in the thermo hydraulic  performance of a solar air heater can be done by enhancing the heat transfer. In general, heat transfer enhancement techniques are divided into two groups: active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective  passive heat transfer technique to enhance the rate of heat transfer to fluid flow. In this  paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve thermo hydraulic performance of a solar air heater, with little penalty of friction and Correlations developed by various researchers with the help of experimental results for heat transfer and friction factor for solar air heater ducts by taking different roughened surfaces geometries are given in tabular form. These correlations are used to predict the thermo hydraulic performance of solar air heaters having roughened ducts. The objective is to provide a detailed review on heat transfer enhancement by using an artificial roughness technique. This paper will be very helpful for the researchers who are researching new artificial roughness for solar air heater ducts to enhance the heat transfer rate and comparing with artificial roughness already studied by various researchers.

9. Sanket Khamitkar et.al. [2003], the thermal efficiency of a solar air collector called unglazed transpired collector (UTC) has been studied using CFD. Experimental results were validated. The study was done to calculate efficiency of solar air heater under hot climatic conditions with two different mass flow rates of air. A commercial finite volume software (CFX) was used to model the heat transfer through the UTC. It was found that temperature rise decreases with increasing air mass flow rate and the efficiency increases with increasing air mass flow rate. Increasing the irradiation level seems to have a very limited effect on the collector efficiency for both mass flow rates. Still, the results show a small increase in efficiency as the irradiation intensity decreases for  both mass flow rates.

10. C.Elaya Perumal et.al. [1998],  the electricity and heat produced simultaneously in a Photovoltaic thermal (PV/T) system from solar energy is about 60-70% efficient. The traditional Photovoltaic (PV) system conversion of electricity from solar energy is only about 6-15% efficient, where as 85% of the incoming solar energy is either reflected or 12

absorbed as heat energy, which are cooled by air coolant to utilize the all incoming solar energy on system. The main novelty in this project work is combination two systems as Photovoltaic Thermal and solar air heating system. The photovoltaic system wasted heat energy is absorbed in cold air. The preheating air from Photovoltaic thermal system is allowed to pass through the air heater, where the hot is much enhanced by the solar radiation and improves the efficiency of  air heating system. There are analyses to configuration on with fins and baffles and with fins and without baffles to improve on thermal efficiency was studied.

11. R S Gill et.al. [2006], In this paper, results of experiment all investigation on heat transfer and friction in rectangular ducts roughened with broken arc-rib roughness combined with staggered rib piece has been presented. The rib roughness has relative gap  position of 0.65, relative staggered rib position of 0.6, relative staggered rib size of 2.0, and relative roughness pitch of 10, arc angle of 30° and relative roughness height of 0.043. The relative gap size was varied from 0.5 to 2.5. The effects of gap size on Nusselt number, friction factor and thermo-hydraulic  performance parameter have been discussed and results compared with smooth duct and continuous arc rib roughened duct under similar conditions.

12. Njoroge G. Ndegwa et.al .  [2001], ex perimental investigations on the  performance of a flat plate solar air heater (SAH) with brown sand as absorber and clear HDPE paper as top cover was done. The efficiency, heat gain factor and heat loss coefficient were determined for the collector. The effects of air mass flow rate and thermal efficiency was also studied. The SAH model was placed outdoors and tests were conducted in an open field between 0900 and 1500 Hrs. and parameters including solar radiation, temperature and air mass flow rates were recorded after every 20 minutes for 100 hours. Results show that, the efficiency increase with increasing air mass flow rate. The highest efficiency obtained was 54% at air mass flow rate of 1.22xl0-5 Kg/s. The temperature difference between the outlet flow and the ambient reduces as the air mass flow rate increases with a maximum difference of 31°C at air mass flow rate of 6.83X10 -6 Kg/s which occurred at 1240 Hrs .13. Anand Patel et.al. [2000], the depletion of fuel sources leads to energy crisis is serious and burning issue. The alternative energy is always better option and out of available resources like solar energy, wind energy and biomass; but compare to wind energy and bio mass solar energy is always better option because solar energy is the easiest source to extract useful energy in terms of availability in ample amount. The objective of  present work is to develop spiral solar air heater and performance will be check using K type thermocouple.

14. S. S. Pawar et.al. [1998], Solar air heater is used to heat air but it has low thermal efficiency because of low thermal conductivity between air and absorber plate. Thermal efficiency of solar air heater can be improved by creating artificial roughness on absorber  plate which causes higher temperature to absorber plate and hence maximum thermal losses 13

occurs to atmosphere. There are number of parameters which enhances the thermal conductivity such as relative roughness height (e/Dh), relative roughness pitch (P/e), Reynolds number (Re), and angle of attack (α).Ex perimental investigations were carried out to study heat transfer enhancement using diamond shape rib on absorber plate of solar air heater. Absorber plate is heated with the solar radiation in outdoor experiment whereas electric heater is used for indoor experiment. Setup is isolated from the three sides with thermocol. The relative roughness pitch (P/E) varies from 10 to 25 mm. The roughened wall has relative roughness height (e/Dh) of 0.023mm and 0.028mm, angle of attack (α) is 0° degree, rib height (e) is 1 mm and 1.25 mm. Duct aspect ratio (W/H=8), rate of air flow corresponds to Reynolds no. (Re) ranging from 3000-14000.

15. L.B.Y. Aldabbagh et.al. [2010], The thermal performances of single and double  pass solar air heaters with steel wire mesh layers are used instead of a flat absorber plate are investigated experimentally. The effects of mass flow rate of air  on the outlet temperature and thermal efficiency were studied. The results indicate that the efficiency increases with increasing the mass flow rate for the range of the flow rate used in this work  between 0.012 and 0.038 kg/s. For the same flow rate, the efficiency of the double pass is found to be higher than the single pass by 34e45%. Moreover, the maximum efficiencies obtained for the single and the double pass air collectors are 45.93 and 83.65% respectively for the mass flow rate of 0.038 kg/s. Comparison of  the results of a packed bed collector with those of a conventional collector shows a substantial enhancement in the thermal efficiency.

16. Pushkar Dwivedi et.al. [2007], The term solar air heating is a technology in which the radiant energy emitted by the sun is captured in an absorber and is used for space heating. Needless to say it is a renewable and pollution free method to produce space heating and when is used in commercial buildings or  industries could be very cost effective. Improvement in the thermo hydraulic performance of a solar air heater can be done by enhancing the heat transfer. In general, heat transfer enhancement techniques are divided into two groups: active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective passive heat transfer technique to enhance the rate of heat transfer to fluid flow. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve thermo hydraulic performance of a solar air heater, is done. The objective of  this paper is to review various studies, in which different artificial roughness elements are used to enhance the heat transfer rate with little penalty of friction. In this review  paper, solar air heaters are discussed along with the  problems associated, when use on large scale. Improvement in present technologies which are used for the manufacture of solar air heaters is the main area of focus in this paper  and recent progress in enhancing the design of solar air duct are reported.

17. Bhupendra Gupta et.al. [1999], an experimental investigation was carried out to study the effect of porous media ( Glass wool and Steel wool) on double pass solar air heater. The aim is to analyse the thermal efficiency of double pass solar air heater using different type of porous media. The measured parameters were temperature difference, air 14

velocity, pressure difference, mass flow rate of the air. Porous media provide large area for the heat transfer have high heat transfer coefficient. This increases the thermal efficiency of the double pass solar air heater with porous media (glass and steel wool) to non- porous media. In this investigation, thermal efficiency of the double pass solar air heater with  porous media is more efficient than the single pass solar air heater with porous media

18. Veena Pal et.al. [2006], in the present work an attempt has been made to experimentally investigate the performance of a flat plate solar air heater. Experiments were performed to find the energy and exergy efficiency at different mass flow rate of air. It is observed that for a 16% increase in mass flow rate of air, energy efficiency increases  by 20%, whereas exergy efficiency increases by 36%.

19. Manash Dey et.al. [2003] , it is well known, that, the heat transfer coefficient  between the absorber plate and working fluid of solar air heater is low. It is attributed to the formation of a very thin boundary layer at the absorber plate surface commonly known as viscous sub-layer The heat transfer coefficient of a solar air heater duct can be increased by  providing artificial roughness on the heated wall (i.e. the absorber plate) The use of artificial roughness on the underside of the absorber plate disturbs the viscous sub-layer of the flowing medium. It is well known that in a turbulent flow a sub-layer exists in the flow in addition to the turbulent core. The purpose of the artificial roughness is to make the flow turbulent adjacent to the wall in the sub-layer region. Experiments were performed to collect heat transfer and friction data for forced convection flow of air in solar air heater rectangular duct with one broad wall roughened by discrete v – groove & v- shape ribs. The range of parameters used in this experiment has been decided on the basis of practical considerations of the system and operating conditions. The range of Reynolds number of 3000-14000, Relative Roughness Height ( eh/D ) of height 0.030 to 0.035, Rib angle of attack 600, heat flux 720 W/m2 and pitch of relative roughness pitch 10 the Result has been compared with smooth duct under similar flow and boundary condition It is found from the investigation that on increasing the roughness of a roughened plate the friction factor andheat transfer performance of solar air heater increase and the rate of increase of heat transfer performance of solar air heater get reduced as the roughness of plate increases.

20. Jitendra Kumar Waiker et.al. [2005], this paper involves an experimental study to investigate the effect of mass flow of Air on thermal performance and pressure drop through the collector. The aim is to analyze thermal efficiency of flat plate solar air heater .The measured parameters were the inlet and outlet temperature, the absorbing plate temperature, and ambient temperature .further the measurements were performed at different value of mass flow rate of air in flow channel duct. It is concluded that smooth  plate double pass solar air heater is 3-4% more efficient than single pass solar air heater. If we use the porous media in double pass solar air heater increase the air heater efficiency to  be 5 % efficient than air heater in single pass, and 2-3% more in double pass without  porous media.

15

21. N.L. Panwar et.al. [1997], in order to produce process heat for drying of agricultural, textile, marine products, heating of buildings and re-generating dehumidify agent, solar energy is one of the promising heat sources for meeting energy demand without putting adverse impact of environment. Hence it plays a key role for sustainable development. Solar energy is intermittent in nature and time dependent energy source. Owing to this nature, PCMs based thermal energy storage system can achieve the more  popularity for solar energy based heating systems. The recent researches focused on the  phase change materials (PCMs), as latent heat storage is more efficient than sensible heat storage. In this paper an attempt has been made to present holistic view of available solar air heater for different applications and their performance.

22. Madhukeshwara. N et.al. [2004], Heat transfer and friction correlations are developed for turbulent flow in solar air heater ducts having a repeated ribbed roughness on the absorber plate. Software program is developed using ‘C++’ programming language to determine the effect of various parameters on heat transfer and friction in solar air heater duct with ribbed absorber plate. This software can be used for iterative work to identify the optimum design parameters. Use of artificial roughness in the form of repeated ribs on the absorber plate has found to be a convenient method for the enhancement of heat absorption capacity of the solar collector. The different parameters of  ribbed roughness are relative roughness pitch (P/E), relative roughness height (e/Dh), and angle of attack of flow (α) and the range of these parameters are decided on the basis of practical considerations of the system and operating conditions. Based on similarity considerations correlations for the  Nusselt number and friction factor in terms of these parameters have been developed.

23. Pankaj Sharma et.al. [2009],  Artificial roughness applied on the absorber plate is the most efficient method to improve thermal performance of solar air heaters. Experimental investigations appropriate to distinct roughness geometries shows that the enhancement in heat transfer is accompanied by considerable rise in pumping power. In view of the fact, a designer needs to carefully examine shape and orientation of roughness elements in order to choose the best fit roughness geometry for intended application. Thermal performance of  conventional solar air heater can be improved by enhancing the heat transfer. Basically heat transfer  enhancement techniques are active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective  passive heat transfer technique to enhance the rate of heat transfer to fluid flow. Attempts have been made to increase heat transfer to air flowing through solar air heater duct using finned absorber, packed bed absorber, corrugated absorber, two-pass air flow, over-lapped glass plates, artificially rib roughened absorber, etc. The convective heat transfer coefficient of solar air heater is low due to the presence of viscous sub layer between the air and absorber plate which can be improved by providing artificial roughness on the heat transferring surface. Artificial roughness in the form of repeated ribs on the absorber plate is an effective technique to enhance the rate of heat transfer to flowing fluid in the roughened duct of solar air heater which also helps to break the laminar sub-layer and creates turbulence in the flow, which reduces the thermal resistance and greatly enhance the heat transfer. Enhancement in heat transfer results in higher thermal efficiency in case 16

of rib roughened solar air heater as compared to conventional solar air heater having ribroughness parameters of relative roughness pitch of 8, angle of attack of 60° relative roughness height of 0.047 and value of Reynolds number from 2564-6206. Finally comparison of  thermal efficiency between smooth and roughened plate under the similar condition of air flow is carried out.

24.

P. T. Saravanakumar et.al. [1998], in this paper, an analysis has been

developed the thermal performance of the flat plate air heater with and without thermal storages experimentally and using artificial neural networks (ANN). In this, ambient temperature, solar intensity and air velocity were used as input layers, while the outputs are collector outlet temperature and efficiency of the solar air heater (SAH). The back  propagation learning algorithm methods were used in training and testing the data. Comparisons between predicted and experimental results are used to indicate that the  proposed ANN model can be used for estimating outlet temperature of the collector and efficiency of SAHs with reasonable accuracy.

25. Yashwant Kumar Vishwakarma et.al. [2007], In double pass solar air heater thermal performance can be obtained by augment the rate of heat transfer and minimizes the top losses and bottom losses. Efficiency of solar air heater is low because of low value of heat transfer coefficient between absorber plate and flowing air. This is due to the  presence of laminar sub layer that need to be broken to increase heat transfer. Therefore for enhancement of heat transfer turbulence is created by providing inclined continuous ribs on absorber plate. This paper presents an experimental investigation carried out to study the effect Inclined continues rib roughness on heat transfer coefficient and friction factor in an artificially roughened solar air heater duct. The experiment encompassed Reynolds number (Re) from 3000 to 15,000. Relative roughness height (e/D) values 0.027, relative roughness  pitch (P/e) range of 6 –12, angle of attack (α) - 600.Extensive experimentation has been conducted to collect data on heat transfer and fluid flow characteristics of a rectangular duct roughened with continues inclined-ribs. Using these experimental data, correlations for Nusselt number and friction factor in terms of roughness geometry and flow parameters have been developed. The roughened wall has roughness with pitch (P), ranging from 9-18 mm, height of the rib of 1.5 mm and duct aspect ratio of 6.67. The air flow rate corresponds to Reynolds number between3000 – 15000. The heat transfer results have been compared with those for smooth ducts under similar flow and thermal boundary condition to determine the thermal efficiency of solar air heater.

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Chapter 3 RESEARCH METHODOLOGY

Problem Identification Identif Parameters for Stud Design Selection Desi n-1 Existin

Desi n-2

Design Simulation of Object Final Design for Object Simulation of final design

Fabrication

NO

Result comparison

Ex erimental validation YES

Optimization of final new design Conclusion

Parameters for Study: 1. Analysis of existing design and New Design 2. Analysis of Final Proposed Design 18

3. Optimization of Final Design 4. Fabrication of Final Design

Tool Used: Finite Element Analysis The useful features of finite element Analysis are as follows: •

Discretization of the whole model into small elements, which may be square, rectangle, and triangle or in polygon shapes.

•

Derive the governing differential equations for each element of the model.

•

Assembly of all elements, based on stability of the solution.

Design Modeler: Autodesk Inventor 2015 •

Autodesk Inventor was introduced in 1999 as an ambitious 3D parametric modeler  based not on the familiar AutoCAD programming architecture but instead on a separate foundation that would provide the room needed to grow into the fully featured modeler it now is, a decade later.

•

Inventor 2015 continues the development of Inventor with assembly layout, plastic  parts, and other productivity tools.

•

The maturity of the Inventor tools coincides with the advancement of the CAD market’s adoption of 3D parametric modelers as a primary design tool.

Analysis Software: ANSYS Mechanical 15.0 ANSYS is a complete FEA software package used by engineers worldwide in virtually all fields of engineering:  –

Structural 19

 –

Thermal

 –

Fluid, including CFD (Computational Fluid Dynamics)

 –

Electrical / Electrostatics

 –

Electromagnetic

A partial list of industries in which ANSYS is used:  –

Aerospace

 –

Automotive

 –

Biomedical

 –

Bridges & Buildings

 –

Electronics & Appliances

 –

Heavy Equipment & Machinery

 –

MEMS - Micro Electromechanical Systems

 –

Sporting Goods

Materials Used: Materials

Stainless Steel, Structural Steel, Gray cast Iron Density Young’s Modulus

Poisson Ratio Material Properties

Bulk Modulus Shear Modulus Tensile Yield Strength Compressive Yield Strength Tensile Ultimate Strength

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Type of Analysis: 1. Stress 2. Strain 3. Deformation 4. Safety Factor 5. Principal Stress 6. Principal Strain

Fig. 3.1

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Chapter 4 MATERIALS AND METHODOLOGY 4.1 MATERIALS USED FOR THERMAL ANALYSIS Thermal analysis is a branch of materials science where the properties of materials are studied as they change with temperature .It is a technique in which a physical property of a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature program. In practice thermal analysis gives properties like; enthalpy, thermal capacity, mass changes and the coefficient of heat expansion. Solid state chemistry uses thermal analysis for studying reactions in the solid state, thermal degradation reactions,  phase transitions and phase diagrams. Thermal analysis Includes several different methods such as:- Thermogravimetric analysis (TGA), mass Differential thermal analysis (DTA), temperature difference ,differential scanning calorimetry (DSC), heat difference, Pressurized TGA (PTGA), mass changes as function of pressure, Thermo mechanical analysis (TMA), deformations and dimension Dilatometer (DIL), volume evolved gas analysis (EGA): gaseous decomposition products. Materials used while analysis of solar air heater are:1. Aluminum 2. Glass

4.1.1 ALUMINIUM Aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminum is the third most abundant element (after oxygen and silicon), and the most abundant metal, in the Earth's crust. It makes up about 8% by mass of the crust, though it is less common in the mantle below. Aluminum metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. The chief ore of Aluminum is bauxite. Aluminum is remarkable for the metal's low density and for its ability to resist corrosion due to the phenomenon of passivation. Structural components made from Aluminum and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials, such as building facades and window frames. The most useful compounds of Aluminum, at least on a weight basis, are the oxides and sulfates. Aluminum is a relatively soft, durable, lightweight, ductile and malleable metal with appearance ranging from silvery to dull gray, depending on the surface roughness. It is nonmagnetic and does not easily ignite. A fresh film of Aluminum serves as a good reflector (approximately 92%) of visible light and an excellent reflector (as much as 98%) of medium and far infrared radiation. The yield strength of pure Aluminum is 7 – 11 MPa, while Aluminum alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminum has 22

about one-third the density and stiffness of steel. It is easily machined, cast, drawn and extruded.

Fig. 4.1 Aluminum Corrosion resistance can be excellent due to a thin surface layer of Aluminum oxide that forms when the metal is exposed to air, effectively preventing further oxidation. The strongest Aluminum alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is also often greatly reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, Aluminum reacts with water to form hydrogen, and in highly alkaline ones to form aluminates —   protective passivation under these conditions is negligible. Also, chlorides such as common sodium chloride are well-known sources of corrosion of Aluminum and are among the chief reasons that household plumbing is never made from this metal. Some of the many uses for Aluminum metal are in: 1. Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles, spacecraft, etc.) as sheet, tube, castings, etc. 2. Packaging (cans, foil, frame of etc.) 3. Construction (windows, doors, siding, building wire, etc.).[56] 4. A wide range of household items, from cooking utensils to baseball bats, watches.[57] 5. Street lighting poles, sailing ship masts, walking poles, etc. 6. Outer shells of consumer electronics, also cases for equipment e.g. photographic equipment, MacBook Pro's casing. 7. Electrical transmission lines for power distribution ("creep" and oxidation are not issues in this application as the terminations are usually multi-sided "crimps" which enclose all sides of the conductor with a gas-tight seal). 8. MKM steel and Alnico magnets

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9. Super purity Aluminum (SPA, 99.980% to 99.999% Al), used in electronics and CDs, and also in wires/cabling. 10. Heat sinks for electronic appliances such as transistors and CPUs.

4.1.2 GLASS Glass is a non-crystalline amorphous solid that is often transparent and has widespread  practical, technological, and decorative usage in, for example, window panes, tableware, and optoelectronics. Scientifically, the term "glass" is often defined in a broader sense, encompassing every solid that possesses a non-crystalline (that is, amorphous) structure at the atomic scale and that exhibits a glass transition when heated towards the liquid state. The most familiar, and historically the oldest, types of glass are based on the chemical compound silica (silicon dioxide), the primary constituent of sand. The term glass, in popular usage, is often used to refer only to this type of material, which is familiar from use as window glass and in glass bottles. Of the many silica-based glasses that exist, ordinary glazing and container glass is formed from a specific type called soda-lime glass, composed of approximately 75% silicon dioxide (SiO2), sodium oxide (Na2O) from sodium carbonate (Na2CO3), calcium oxide, also called lime (CaO), and several minor additives. A very clear and durable quartz glass can be made from pure silica which is very tough and resistant to thermal shock, being able to survive immersion in water while red hot. However, quartz must  be heated to well over 3,000 °F (1,650 °C) (white hot) before it begins to melt, and it has a very narrow glass transition, making glassblowing and hot working difficult. In glasses like soda lime, the other compounds are used to lower the melting temperature and improve the temperature workability of the product at a cost in the toughness, thermal stability, and optical transmittance.

Fig. 4.2 Glasses Glass is in widespread use largely due to the production of glass compositions that are transparent to visible light. In contrast, polycrystalline materials do not generally transmit visible light. The individual crystallites may be transparent, but their facets (grain boundaries) reflect or scatter light resulting in diffuse reflection. Glass does not contain the internal subdivisions associated with grain boundaries in polycrystals and hence does not scatter light in the same manner as a polycrystalline material. The surface of a glass is often smooth since during glass formation the molecules of the super cooled liquid are not forced to dispose in rigid crystal geometries and can follow surface tension, which imposes a microscopically 24

smooth surface. These properties, which give glass its clearness, can be retained even if glass is partially light-absorbing — i.e., colored. Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified  by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties. According to Fresnel equations, the reflectivity of a sheet of glass is about 4% per surface (at normal incidence in air), and the transmissivity of one element (two surfaces) is about 90%. Glass with high germanium oxide content also finds application in optoelectronics — e.g., for light-transmitting optical fiber. Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in  photochromic glasses).Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron (II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfide and produce amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber color from a reducing combustion atmosphere.

4.2 Modeling & Designing Tools 4.2.1 CREO Creo is a family or suite of design software supporting product design for discrete manufacturers and is developed by PTC. The suite consists of apps, each delivering a distinct set of capabilities for a user role within product development. Creo runs on Microsoft Windows and provides apps for 3D CAD parametric feature solid modeling, 3D direct modeling, 2D orthographic views, Finite Element Analysis and simulation, schematic design, technical illustrations, and viewing and visualization. Creo Elements/Pro and Creo Parametric compete directly with CATIA, Siemens NX/Solid edge, and Solid works. The Creo suite of apps replace and supersede PTC’s products formerly known as Pro/ENGINEER, Co Create, and Product View. PTC began developing Creo in 2009, and announced it using the code name Project Lightning at Planet PTC Live, in Las Vegas, in June 2010. In October 2010, PTC unveiled the product name for Project Lightning to be Creo. PTC released Creo 1.0 in June 2011.Creo apps are available in English, German, French, Italian, Spanish, Japanese, Korean, Chinese Simplified, and Chinese Traditional. The extent of localization varies from full translation of the product (including Help) to user interface only. Creo is part of a broader  product development system developed by PTC. It connects to PTC’s other solutions that aid  product development, including Wind-chill for Product Lifecycle Management (PLM), Mathcad for engineering calculations and Arbor text for enterprise publishing software. 25

Fig. 4.3 Product designed in CREO

4.2.2 AUTODESK INVENTOR Autodesk Inventor, developed by U.S. based software company Autodesk, is a computeraided design application for creating 3D digital prototypes used in the design, visualization and simulation of products. It uses Shape Manager, their proprietary geometric modeling kernel. Autodesk Inventor competes directly with Solid Works and Solid Edge. Inventor includes an integrated motion simulation and assembly stress analysis environment. Users can input driving loads, friction characteristics, and dynamic components, then run dynamic simulation tests to see how a product will work under real-world conditions. The simulation tools can help users optimize strength and weight, identify high-stress areas, identify and reduce unwanted vibrations, and size motors and actuators to reduce energy consumption. Finite element analysis (FEA) lets users validate component design by testing how parts  perform under loads (using actual load information instead of estimates). Inventor’s Parametric Studies and Optimization technology lets users modify design parameters from within the assembly stress environment and compare various design options, then update the 3D model with the optimized parameters. Inventor uses specific file formats for parts (IPT), assemblies (IAM), and drawing views (IDW or DWG). Files can be imported or exported in DWG format. Design Web Format (DWF) is Autodesk’s preferred 2D/3D data exchange and review format. Inventor includes a Building Information Modeling (BIM) Exchange tool, used to create and  publish simplified 3D representations, intelligent connection points, and additional information in native file formats for AutoCAD MEP (mechanical, electrical and plumbing) software. Users can export 3D geometry to AutoCAD Architecture, Revit-based software, and AutoCAD software, and exchange data with industrial design software such as Autodesk Alias Design.

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Fig. 4.4 Structure designed in Autodesk inventor Inventor is also used to design mechatronic systems since it is interoperable with electrical software applications such as AutoCAD Electrical and E-plan. Inventor can exchange data with applications such as CATIA V5, UGS, Solid Works, and Pro/ENGINEER. Inventor 27

supports direct import and export of CATIA V5, JT 6, JT 7, Para solid, Granite, UG-NX, Solid Works, Pro/E, and SAT files. The Inventor Construction Environment provides faulttolerant import of large STEP and IGES data sets. Quarantine holds entities containing geometric problems, such as surface slivers and mismatched boundary curves. Users can  publish drawings as PDF files, publish 3D part and assembly models in SAT or JT formats, or create STL files for output to stereo lithography and 3D print machines.

4.3 Discretization Method In mathematics, discretization concerns the process of transferring continuous functions, models, and equations into discrete counterparts. This process is usually carried out as a first step toward making them suitable for numerical evaluation and implementation on digital computers. Processing on a digital computer requires another process called quantization. Dichotomization is the special case of discretization in which the number of discrete classes is 2, which can approximate a continuous variable as a binary variable (creating a dichotomy for modeling purposes). Discretization is also related to discrete mathematics, and is an important component of granular computing. In this context, discretization may also refer to modification of variable or category granularity, as when multiple discrete variables are aggregated or multiple discrete categories fused 4.3.1 Finite Element Method The finite element method (FEM) is a numerical technique for finding approximate solutions to boundary value problems for partial differential equations. It is also referred to as finite element analysis (FEA). FEM subdivides a large problem into smaller, simpler, parts, called finite elements. The simple equations that model these finite elements are then assembled into a larger system of equations that models the entire problem. FEM then uses vibrational methods from the cal. The subdivision of a whole domain into simpler parts has several advantages: 1. 2. 3. 4.

Accurate representation of complex geometry Inclusion of dissimilar material properties Easy representation of the total solution Capture of local effects ulus of variations to approximate a solution by minimizing an associated error function.

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A linear differential equation can be of the following form: Lu q = + 0 Where u is the vector of primary variables of the problem, which are functions of the coordinates, L is the differential operator and q is the vector of known functions. This differential equation will be subjected to boundary conditions, which are usually of two types- (i) the essential boundary conditions (ii) the natural boundary conditions. The essential  boundary conditions are the set of boundary conditions that are sufficient for solving the differential equations completely. The natural boundary conditions are the boundary conditions involving higher order derivative terms and are not sufficient for solving the differential equation completely, requiring at least one essential boundary condition. For example, consider the differential equation: d/dx (EAdu/dx) + q=0 This problem can be solved completely under one of the following two conditions: (i) u is prescribed at both ends. (ii) u is prescribed at one end and du/dx is prescribed at the same or other end. However, the problem cannot be solved if only du/dx is prescribed at both ends. Thus, we surely require one boundary condition prescribing u. Therefore, for this problem u= u* is an essential boundary condition and du/dx= (du/dx)* is a natural boundary condition, where * indicates the prescribed value. Now consider the differential equation. d2/dx2(EId2w/dx2)-q=0 This differential equation can be solved completely by specifying w and dw/dx at both ends. One can also specify d2w/dx2 and/or d3w/dx3 as boundary conditions, however out of total four boundary conditions, two must be of one of the following forms: (i) w prescribed at both ends.

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(ii) w prescribed at one end and dw/dx prescribed at the other end. Thus, the prescribed values of w and dw/dx form the part of essential boundary conditions and prescribed values of d2w/dx2 and d3w/dx3 form the part of natural boundary conditions. Two popular FEM formulations are Galerkin formulation and Ritz formulation. In Galerkin formulation, the primary variable is approximated by a continuous function inside the element. When the approximate primary variable ue is substituted in Eq. (1), we shall get residue depending on the approximating function, i.e.,

L + eu q = R A typical work out of the method involves (1) dividing the domain of the problem into a collection of subdomains, with each subdomain represented by a set of element equations to the original problem, followed by (2) systematically recombining all sets of element equations into a global system of equations for the final calculation. The global system of equations has known solution techniques, and can be calculated from the initial values of the original problem to obtain a numerical answer.

Fig. 4.5 In the first step above, the element equations are simple equations that locally approximate the original complex equations to be studied, where the original equations are often partial differential equations (PDE). To explain the approximation in this process, FEM is commonly introduced as a special case of Galerkin method. The process, in mathematical language, is to construct an integral of the inner product of the residual and the weight functions and set the integral to zero. In simple terms, it is a procedure that minimizes the error of approximation by fitting trial functions into the PDE. The residual is the error caused  by the trial functions, and the weight functions are polynomial approximation functions that

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 project the residual. The process eliminates all the spatial derivatives from the PDE, thus approximating the PDE locally with 1. A set of algebraic equations for steady state problems. 2. A set of ordinary differential equations for transient problems. These equation sets are the element equations. They are linear if the underlying PDE is linear, and vice versa. Algebraic equation sets that arise in the steady state problems are solved using numerical linear algebra methods, while ordinary differential equation sets that arise in the transient problems are solved by numerical integration using standard techniques such as Euler's method or the Runge-Kutta method.

Fig. 4.6 FEM mesh refinement In step (2) above, a global system of equations is generated from the element equations through a transformation of coordinates from the subdomains' local nodes to the domain's global nodes. This spatial transformation includes appropriate orientation adjustments as applied in relation to the reference coordinate system. The process is often carried out by FEM software using coordinate data generated from the subdomains. FEM is best understood from its practical application, known as finite element analysis (FEA). FEA has applied in engineering is a computational tool for performing engineering analysis. It includes the use of mesh generation techniques for dividing a complex problem into small elements, as well as the use of software program coded with FEM algorithm. In applying FEA, the complex  problem is usually a physical system with the underlying under lying physics ph ysics such as the Euler-Bernoulli Euler-Bernou lli  beam equation, equ ation, the t he heat equation, or the Navier-Stokes equations expressed in either PDE or integral equations, while the divided small elements of the complex problem represent different areas in the physical system .FEA is a good choice for analyzing problems over complicated domains (like cars and oil pipelines), when the domain changes (as during a solid state reaction with a moving boundary), when the desired precision varies over the entire domain, or when the solution lacks smoothness. For instance, in a frontal crash 31

simulation it is possible to increase prediction accuracy in "important" areas like the front of the car and reduce it in its rear (thus reducing cost of the simulation). Another example would  be in numerical weather prediction, where it is more important to have accurate predictions over developing highly nonlinear phenomena (such as tropical cyclones in the atmosphere, or eddies in the ocean) rather than relatively calm areas.

4.3.2 Mesh generation Mesh generation is the practice of generating a polygonal or polyhedral mesh that approximates a geometric domain. The term "grid generation" is often used interchangeably. Typical uses are for rendering to a computer screen or for physical simulation such as finite element analysis or computational fluid dynamics. The input model form can vary greatly but common sources are CAD, NURBS, B-rep, STL (file format) or a point cloud. The field is highly interdisciplinary, with contributions found in mathematics, computer science, and engineering. Three-dimensional meshes created for finite element analysis need to consist of tetrahedral,  pyramids, prisms or hexahedra. Those used for the finite volume method can consist of arbitrary polyhedral. Those used for finite difference methods usually need to consist of  piecewise structured stru ctured arrays arra ys of hexahedra h exahedra known kno wn as multi-block structured meshes. A mesh is otherwise a discretization of a domain existing in one, two or three dimensions. The grid generation by algebraic methods is done by using known functions in one, two or three dimensions taking arbitrary shaped regions. The computational domain might not be rectangular one, but for the sake of simplicity, the domain is taken to be rectangular. The simplest procedure that may be used to produce boundary fitted computational mesh is the normalization transformation. For a nozzle, with the describing function y = x2  the grid can easily be generated using uniform division in y-direction with equally spaced increments in x-direction, which are described by Ε=x ὴ=y/ymax

4.4

Thermal Analysis Tool

4.4.1 CFD or Computational Fluid Dynamics Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical analysis and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. With high-speed supercomputers, better solutions can be achieved. Ongoing research yields software that improves the accuracy and speed of complex simulation scenarios such as transonic or

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turbulent flows. Initial experimental validation of such software is performed using a wind tunnel with the final validation coming in full-scale testing, e.g. flight tests. Computational fluid dynamics has been around since the early 20th century and many people are familiar with it as a tool for analyzing air flow around cars and aircraft. As the cooling infrastructure of server rooms has increased in complexity, CFD has also become a useful tool in the data center for analyzing thermal properties and modeling air flow. CFD software requires information about the size, content and layout of the data center. It uses this information to create a 3D mathematical model on a grid that can be rotated and viewed from different angles. CFD modeling can help an administrator identify hot spots and learn where cold air is being wasted or air is mixing Simply by changing variables, the administrator can visualize how cold air will flow through the data center under a number of different circumstances. This knowledge can help the administrator optimize the efficiency of an existing cooling infrastructure and predict the effectiveness of a particular layout of IT equipment. For example, if an administrator wanted to take one rack of hard drive storage and split the hard drives over two racks, a CFD  program could simulate the change and help the administrator understand what adjustments would be need to be made to deal with the additional heat load before any time or money has  been spent The fundamental basis of almost all CFD problems are the Navier   – Stokes equations, which define any single-phase (gas or liquid, but not both) fluid flow. These equations can be simplified by removing terms describing viscous actions to yield the Euler equations. Further simplification, by removing terms describing vortices yields the full potential equations. Finally, for small perturbations in subsonic and supersonic flows (not transonic or hypersonic) these equations can be linearized to yield the linearized potential equations. Historically, methods were first developed to solve the linearized potential equations. Twodimensional (2D) methods, using conformal transformations of the flow about a cylinder to the flow about an airfoil were developed in the 1930s.

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Fig. 4.7 CFD Analysis In all of these approaches the same basic procedure is followed. 1. During preprocessing 1.1 The geometry (physical bounds) of the problem is defined. 1.2 The volume occupied by the fluid is divided into discrete cells (the mesh). The mesh may be uniform or non-uniform.

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1.3 The physical modeling is defined  –   for example, the equations of motion + enthalpy + radiation + species conservation 1.4 Boundary conditions are defined. This involves specifying the fluid behavior and  properties at the boundaries of the problem. For transient problems, the initial conditions are also defined. 2. The simulation is started and the equations are solved iteratively as a steady-state or transient. 3. Finally a postprocessor is used for the analysis and visualization of the resulting solution.

4.5 Component of Solar Air Heater In this project, we have taken solar air heater with three different surfaces into consideration that are plain surface, normal zig-zag surface and inclined zig-zag surface. Aluminum and glass is used to make the solar air heater. Instead of normal window glass, toughened glass has utilized in this research work. Thermal losses of cover due to convection as well as radiation process are assumed as constant. Due to corrugated shape of absorber plate, easily air flow will occur so no vent is required in solar air heater. Aluminum cans have used to create obstruction on the way of air and to increase temperature as well as thermal efficiency of solar air heater. Each Aluminum can was opened on top as well as bottom to receive air flow from it. Inlet as well as outlet temperatures were measured. Solar air heater performance tests were conducted on days with clear sky condition means without clouds in the sky, hence the amount of direct radiation will be more. Here, mass flow rate remains constant.

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Chapter 5 ANALYSIS OF SOLAR AIR HEATER  In this chapter we have to deal with the analysis of solar air heater on the software “ANSYS WORKBENCH 15.0” and also using “ANSYS FLUENT SOLVER” for solving the results for analysis. We have to do the analysis of a solar air heater using CFD as a tool. For this we take a defined geometry made from CREO/AUTODESK INVENTOR. In practically the geometry is made from the aluminum and glass materials. We have to analysis the amount and efficiency of air heated by the solar heater by taking three types of different designs and do analysis on them and adapt a best design for solar air heater.

5.1 Analysis tools: 5.1.1 Ansys workbench 15.0 Ansys workbench 15.0 is a released version of Ansys analysis software. It is a product of Ansys, Inc. which is an American Computer-aided engineering software company.it is headquartered south of Pittsburgh in Cecil Township, Pennsylvania, and United States. Ansys  publishes engineering analysis software has a range of disciplines including finite element analysis, structural analysis, computational fluid dynamics, explicit and implicit methods, and heat transfer. ANSYS 15.0 is the last version of Ansys software that has to be support Windows XP operating system, Windows 7 (32-bit) operating system, and the Windows 32 bit platform.

Fig. 5.1 Ansys 15.0 is similar to its older versions with the often commands and it has a classic Ansys interface, the last few years have seen the company focus on moving both its core structural analysis tools (as well as the long list of acquisitions in recent years) to the Workbench  platform. Workbench provides a single interface to all of Ansys’ tools. From the classic

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structural tools to the various CFD solvers and technologies it has access to (Ansys acquired  both Fluent and CFX in recent years) and the more special purpose technologies in its stable. The goal is to provide a single platform that allows users to take advantage of a more simple, schematic style approach to build simulation tasks. It’s driven by building up and connecting different building blocks. Each of these blocks allows you to take inputs and outputs from one stage and feed them into the next or indeed, multiple processes. The clever part is how Workbench 15.0 is handling the transformation and repurposing of that data. Some of the basic features of ansys workbench 15.0 and the improvements over the previous versions are following-: User customization

Workbench 15.0 rewrote the book on how Ansys users interacted with the underlying technology, but it’s also the case that longtime users have a lot of experience and knowledge  built into scripts, automation routines and other in-house developed items. The last few releases have seen the ACT (Ansys Customization Template) environment start to flesh out. This enables users to take their own assets and publish them for others to take advantage of, perhaps bringing them into Workbench as entities on their own or even distributing them publically through an app store like approach. Large complex models

When it comes to large simulation tasks (in terms of geometry complexity), workbench 15.0 has a few tricks up its sleeve. Much of this centers on the ability to use the most appropriate modelling technique to solve the problems we are working on then change it to focus in on details where needed and best illustrated by stepping through the workflow. We can see a screenshot of ansys workbench 15.0 handling a complex model.

Fig. 5.2

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Meshing updates

The big change on the meshing front for this release 15.0 is that the core meshing tools in Ansys now run across multiple cores/threads. What’s interesting is how this has changed. In previous releases, it worked in serial, meshing the first part, then the second, then the next and so on. Now, Ansys works in parallel on a per  part basis and does so without the inherent limitations of Ansys.in short if you have got a workstation with multiple cores or threads available, it will use them to process your meshing tasks. In 15.0 onwards, it’s now possible to begin a simulation process using previously created meshes, rather than pure analytic geometry from a 3D CAD system. This allows a couple of workflows to function. Composite design

Moving onto more specialist updates, the Ansys 15 release sees work accelerating on the composites simulation front. While the last major release saw Workbench gain tools to assist with the complex business of defining how composite materials are defined in the system, this 15.0 release sees that work move on and greater integration with ACP (Ansys Composite Prep/Post) for pre and post processing these types of models, from sheet material definition to  ply orientation and into how the models are built from the ground up. Contact and bolt pre-tension

While nowhere near as specialist as composites, another area that’s seen greater intelligence added is in the definition of bolt pretension. In previous versions simulation of define a bolted connection between two or more components is complex. 3D CAD integrated simulation tools tend to provide the user with pre-configured tools to define the bolt, tension and influenced areas on a mesh. Ansys workbench 15.0 extends this type of automated tool to give you much greater control we are not only working with real-world values (such as thread pitch), but also pitch diameter, thread starts, thread direction (left or right handed) etc.

The results are computed quickly and once established, can be reused wherever needed in the same model or indeed, across multiple studies. Exporting Results for Fluid Solid Interface

Compared to the pervious release, the Export Results property of the Fluid Solid Interface  boundary condition in workbench 15.0 is now, by default, set to No. Solving Units

Mechanical analysis now supports a new unit quantity, Temperature Gradient, for temperature changes per unit length. Contact and Connection Enhancements

The Connections Worksheet now provides information for the properties of Spring Connections and Beam Connections

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Fig. 5.3 Design 1 –  Plain surface

Fig. 5.4 Design 2 –  Normal Zig zag surface

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Fig. 5.5 Design 3 –  Inclined zig zag surface

Graphics Enhancements

 New graphic tools are introduced in workbench 15.0 Mapping Enhancements

Mapping validation objects can now be inserted under imported data objects from linked analyses (Thermal Stress, Sub modeling, and Acoustic Coupling). Loads/Supports enhancements

• For a Harmonic Analysis, the following boundary conditions now support frequency dependent tabular loading.

-Acceleration -force - Moment -Pressure - Remote Force So these are some features and improvements in workbench 15.0.

5.1.2 Ansys fluent solver: We have to do the analysis of a solar air heater using CFD (Computational Fluid Dynamics) as a tool so we have to use Ansys fluent solver for solving the results of analysis. Computational Fluid Dynamics (CFD) is the science of predicting fluid flow, heat and mass 40

transfer, chemical reactions, and related phenomena by solving numerically the set of governing mathematical equations.

The results of CFD analyses solving with the fluent solver.  –  Conceptual studies of new designs  –  Detailed product development  –   Troubleshooting  –  Redesign Ansys fluent solver comes with the Ansys workbench 15.0 or basically we can sa y it’s a part or function of Ansys workbench 15.0.

Various models which are introduced in Ansys fluent solver 15.0 Turbulence

A new sub grid-scale model is available for the large eddy simulation (LES) model, called the Wall Modeled LES S-Omega approach. It is an enhancement of the WMLES approach. WMLES does not provide zero eddy-viscosity for flows with constant shear. Consequently, it does not allow the computation of transitional effects, and can produce overly large eddyviscosities in separating shear layers. Heat Transfer and Radiation

The ability to use multi-layer shells to model heat transfer in the normal and planar directions of walls made up of layers of different materials. Combustion and Species Transport

•A reactor network model is available for modeling detailed chemical kinetics as a network of stirred reactors. •A new spark model has been implemented that is much less sensitive to numerical  parameters such as mesh and time-step size. Discrete Phase Model

•Ability to calculate unsteady time statistics (mean and RMS) for discrete phase particle quantities. • Ability to specify discrete phase density as a function of temperature. Eulerian Multiphase Model

 New methods for specifying/computing interphase heat-transfer coefficients in the Eulerian multiphase model.

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Fig. 5.6 Result 1 –  Plain surface

Fig. 5.7 Result 2 –  Normal zig zag surface

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Fig. 5.8 Result 3 –  Inclined zig zag surface

Eulerian Wall Film Model

The phase change option of Eulerian wall film model is now compatible with the mixture and the Eulerian multiphase models.

For a given problem or analysis we will have to follow these steps to solve it by ansys fluent solver. -Define material properties. -Select appropriate physical models available in fluent solver (Turbulence, discrete  phase, multiphase, etc.). -Prescribe operating conditions. -Prescribe boundary conditions at all boundary zones. -Provide initial values or a previous solution. -Set up solver controls. Here are some features of Ansys fluent solver 15.0. 43

Solver-Numeric

• Mesh interfaces between solid zones of t he same material are now created as interior-type interfaces rather than coupled-wall interfaces. This improves mesh-read performance for cases with many solid zone interfaces. • A new option has been added to use Laplace coefficients for coarsening in the AMG solver. Solver-Meshing • A node-based algorithm is now used for diffusion-based smoothing offering improved robustness. In addition, a new smoothing method is available which is based on the equations for a linearly elastic solid. Material Properties • We can define and edit materials in the Create/Edit Materials dialog box while using the single species and multi-species NIST real gas models.

• We can set the phase (liquid or vapor) for a specific fluid zone for the real -gas models. Cell Zone and Boundary Conditions

• When using the Non -Reflecting Boundary Condition option at a pressure-outlet with the  pressure based solver, we can specify whether to use Static Pressure or Total Pressure for Backflow Pressure Specification. Mesh Optimizer

• Ability t o select multiple control points and multiple parameters when defining the scaling factor settings for the mesh optimizer.

5.2 Environmental conditions:Environmental conditions for a solar air heater that the environment in which the solar air heater is placed during its working or analysis. We have to do the analysis of air heater which is placed on the rooftop of a building in Jaipur. For this we have to define some specific environmental properties of Jaipur. Which are as followsLatitude coordinate of Jaipur in decimals-20.0 Longitude coordinate of Jaipur-77.0 Time zone of Jaipur-GMT+5.30 Weather conditions-winter The solar air heater is placed in open environment so that it can absorbs, reflects and transmits the sun rays and heat the air which passes through it. For proper flow of air through it we have to use a blower.The various phenomenon or process that takes place due to surrounding environment of solar air heater.    

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Radiation-radiation is the emission or transmission of energy in the form of waves or  particles through space or through a material medium. In solar air heater the radiation takes place by the rays of sun which directly implies on the glass plate of the solar air heater thus it get heated by the radiation of sun. Radiation in solar air heater consists of three sub-process which are as follows-

Fig. 5.9 Absorption-glass plate of solar air heater absorbs the sun rays and gain heat from it and transferred it to air and thus air get heated. This radiation is known as absorbed radiation. Reflection-some part of the radiation is reflected by the glass plate which is called as reflected radiation.it gives heat to the upper part of glass plate. Transmission-some of the part of radiation gets transmitted through the glass plate and the heated the air which was flowing through the solar air heater. Radiation in solar air heater depends upon following factors   

Design of solar air heater. Material of solar air heater body. Material of upper glass plate of solar air heater. Environmental conditions of place at which the analysis have to be done.

5.3 Boundary conditions :Boundary conditions of solar air heater defines the boundary characteristics of the various  parts of solar air heater. At first air goes from air blower to the air inlet part which is made of aluminum material. Mid part of body of solar air heater have four sides three sides which called walls are made of aluminum material and upper wall which have directly face the solar rays is made of glass material and the end part is air outlet part and made from the aluminum material.

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Chapter 6 RESULT

Fig. 6.1 Result A Three- dimensional Computational fluid dynamics (CFD) analysis has been carried out to study heat transfer behavior in a rectangular duct of solar air heater having plain surface and artificial roughness. Three surfaces are taken into consideration: plain surface, normal zig zag surface and inclined zig zag surface. By the CFD analysis, we found that efficiency of solar air heater with plain surface rectangular duct is more than the solar air heater with normal zig zag and inclined zig zag surface. It can be seen from fig. 22 that the enhancement in heat transfer of the abnormal duct with respect to the smooth duct is less.

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Chapter 7 APPLICATIONS Types of applications for solar air heating are numerous: Production plants, factories, workshops, warehouses, exhibition halls, offices, institutional facilities, theatres, gymnasiums, dryers, cleaners. The right solar heating product will perform  best if properly integrated within the HVAC and control system of the building.

Solar air heating connected to the make-up air unit:This application is the most common. The solar air collector is mounted upstream of the make-up air unit, preheating the air before it reaches the burner. In this configuration, any solar heat gain is a useful energy gain, e.g. will save fuel. Even on cloudy winter days, a relatively low temperature rise of 5C will result in fuel and money savings. This set-up is to be used preferably if the operating hours of the unit are over 6 hours per day, 5 days a week.

Fig. 7.1

Solar air heating in parallel with the make-up air unit:In this application, the fan pulls in outside air through the solar collectors and mixes it with inside, with interlocked mixing dampers, so that air is delivered at a constant supply temperature inside the building. As a result, outside air flow may vary depending on sunshine and weather conditions. Advantages of this configuration include: 

Solar gains at all times, even during unoccupied periods (week-ends)



Mechanically independent of the gas-fired make-up air unit



Linked with other HVAC components via automated controls 47



Oxygen-rich heated fresh air supply (as opposed to fuel gas from direct-fired units)

Fig. 7.2 This configuration is generally used if the gas-fired unit works irregularly, upon gas detection (alarm) or if the make-up air unit cannot easily de ducted to the solar air heater.

Solar air heating within loop of roof-top unit:Thanks to our line of roof mounted solar panels which deliver heat even in the coldest conditions, preheat the air before it reaches the ventilation unit.

Fig.7.3

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Chapter 8 CONCLUSION A Three- dimensional Computational fluid dynamics (CFD) analysis has been carried out to study heat transfer behavior in a rectangular duct of solar air heater having artificial roughness. There is a good agreement between the experimental and simulated results for outlet air temperatures. The Nusselt number of CFD results has maximum ±8.73 % over experimental results. In this present investigation, a prediction has been conducted to study heat transfer behaviors of a rectangular duct of a solar air heater having plain surface and artificial roughness on the absorber plate. The main conclusions are: 1. There is no doubt that a major focus of CFD analysis of solar air heater is to enhance the design process that deals with the heat transfer and fluid flow. 2. In recent years CFD has been applied in the design of solar air heater. The quality of the solutions obtained from CFD simulations are largely within the acceptable range proving that CFD is an effective tool for predicting the behavior and performance of a solar air heater. 3. Solar air heater with plain surface have better efficiency of heat transfer as compared to abnormal surface.

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Chapter 9

FUTURE SCOPE India has tremendous scope of generating solar energy. The geographical location of the country stands to its benefit for generating solar energy. The reason being India is a tropical country and it receives solar radiation almost throughout the year, which amounts to 3,000 hours of sunshine. This is equal to more than 5,000 trillion kWh. Almost all parts of India receive 4-7 kWh of solar radiation per sq. metres. This is equivalent to 2,300 – 3,200 sunshine hours per year. States like Andhra Pradesh, Bihar, Gujarat, Haryana, Madhya Pradesh, Maharashtra, Orissa, Punjab, Rajasthan, and West Bengal have great potential for tapping solar energy due to their location. Since majority of the population lives in rural areas, there is much scope for solar energy being promoted in these areas. Use of solar energy can reduce the use of firewood and dung cakes by rural household. Solar air heating is a solar thermal technology in which the energy from the sun, insolation, is captured by an absorbing medium and used to heat air. Solar air heating is a renewable energy heating technology used to heat or condition air for buildings or process heat applications. It is typically the most cost-effective out of all the solar technologies, especially in commercial and industrial applications, and it addresses the largest usage of building energy in heating climates, which is space heating and industrial process heating. Computational fluid dynamics (CFD) is a powerful numerical tool that is becoming widely used to simulate many processes in the food industry. Recent progression in computing efficacy coupled with reduced costs of CFD software packages has advanced CFD as a viable technique to provide effective and efficient design solutions. This paper discusses the fundamentals involved in developing a CFD solution. It also provides a state-of-the-art review on various CFD applications in the food industry such as ventilation, drying, sterilisation, refrigeration, cold display and storage, and mixing and elucidates the physical models most commonly used in these applications. The challenges faced by modellers using CFD in the food industry are also discussed. We used CFD as tool for thermal analysis in solar air heater because it gives effective and eff icient result compared to the manual thermal analysis. We can’t differentiate higher order differential equation more than two times manually because it’s very complicated mathematical problem but by using FEM and CFD as a tool we can differentiate higher or more higher differentiate equation with 10th  power 9 times and we have probability to get error 0%. We are being more cautious about losses so firstly we have done thermal analysis of solar air heater on different model and lastly we get a model which is more effective and efficient compare to other models so we have used it. Solar air heater uses solar energy and rises the temperature of air at a particular limit which we want, so without using electricity and fuel we get hot air with no maintenance only set up cost introduced in it.

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