Solar Water Purifier 1

1

A MAJOR PROJECT REPORT ON

SOLAR WATER PURIFIER SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF BACHELOR OF TECHNOLOGY BY B. RAMULU

09241A0329

P.MURALI KRISHNA V. NARESH

10245A0307 10245A0311

UNDER THE GUIDANCE OF

Mr. P.P.C. PRASAD ASSOCIATE PROFESSOR

Department of Mechanical Engineering Gokaraju Rangaraju Institute of Engineering and Technology Bachupally-HYDERABAD-500 090, A.P., INDIA April 2013

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CONTENTS

S.NO.

1

NAME OF THE CHAPTER

Chapter - 1 INTRODUCTION

2

1 2

Chapter - 2 SOLAR STILL

3.

PAGE NO.

Chapter – 3

3

WORKING OF SOLAR WATER PURIFIER 3.1.Working principle 3.2.supply fills ports 3.3 over flow port 3.4. distilled output collection port 3.5.solar still background 4.

Chapter -4

6

TROUBLESHOOTING 4.1.white crusty bottom inside purifier 4.2. Large drops of water on underside of glass. 4.3.broken glass 4.4.bobbles in liner

5.

6.

Chapter-5 SOALAR ENERGY

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Chapter-6

9

SOLAR RADIATION 6.1.solar radiation outside the earth’s atmosphere 6.2.beam or direct radiation 6.3.soalr radiation at the earth surface 6.4.measurement of solar radiation

3

7.

Chapter -7 SOLAR WATER PURIFICATION SYSTEM

7.1. solar energy storage

7.2.solar constant 8.

Chapter-8 DESIGHN OF SOLAR WATER PURIFICATION PLANT 8.1.details of different parts of the system 8.1.1.still basin 8.1.2.top cover 8.1.3.channel 8.1.4.side walls 8.1.5.support for top cover

9.

Chapter-9 MATERIALS TO BE USED 9.1.properties 9.2about mild steel Chapter-10

10.

DESIGHN CALCULATIONS

11.

Chapter-11 TECHNICAL REPORT 11.1.results and discussions 11.2.readings taken for still 11.3.observations 11.4.tested of purifier

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12.

Chapter-12 CONCLUSION Chapter-13 BIBILOGRAPHY

LIST OF FIGURES 13. S.NO.

1.

NAME OF THE DIAGRAM

PAGE NO.

Chapter-7 7.1 purification system 7.2 solar panel 7.3 water in atmosphere 7.4 difference between boiling and evaporation

12 13 15 16

2. Chapter - 8 8.0.1.desighn of solar purification plant 8.0.2. proposed model of solar distillation system 8.1.1.still basin 8.1.2.top cover 8.1.3.chaannel 8.1.4.sidewall 8.1.5.working model of solar distillation system

20 21 22 23 24 25 26

LIST OF TABLES

S.NO.

NAME OF THE TABLE

1.

Chapter-11 11.2.1. reading for solar still

PAGE NO.

32

5

LIST OF FIGURES

NAME OF THE DIAGRAM

S.NO.

1.

Chapter-7 7.1 7.2 7.3 7.4

2.

PAGE NO.

purification system solar panel water in atmosphere difference between boiling and evaporation

Chapter - 8 8.0.1.desighn of solar purification plant 8.0.2. proposed model of solar distillation system 8.1.1.still basin 8.1.2.top cover 8.1.3.chaannel 8.1.4.sidewall 8.1.5.working model of solar distillation system

LIST OF TABLES

S.NO.

NAME OF THE TABLE

Chapter-11

PAGE NO.

6 1.

11.2.1. reading for solar still

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ABSTRACT

There is almost no water left on earth that is safe to drink without purification after 20-25 years from today. This is a seemingly bold statement, but it is unfortunately true. Only 1% of Earth's water is in a fresh, liquid state, and nearly all of this is polluted by both diseases and toxic chemicals. For this reason, purification of water supplies is extremely important. Keeping these things in mind, we have devised a model which will convert the dirty/saline water into pure/potable water using the renewable source of energy (i.e. solar energy). The basic modes of the heat transfer involved are radiation, convection and conduction. The results are obtained by evaporation of the dirty/saline water and fetching it out as pure/drinkable water. The designed model produces 1.5 litres of pure water from 14 litres of dirty water during six hours.

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Chapter-1

INTRODUCTION Water is the basic necessity for human along with food and air. There is almost no water left on Earth that is safe to drink without purification. Only 1% of Earth's water is in a fresh, liquid state, and nearly all of this is polluted by both diseases and toxic chemicals. For this reason, purification of water supplies is extremely important. Moreover, typical purification systems are easily damaged or compromised by disasters, natural or otherwise. This results in a very challenging situation for individuals trying to prepare for such situations, and keep themselves and their families safe from the myriad diseases and toxic chemicals present in untreated water. Everyone wants to find out the solution of above problem with the available sources of energy in order to achieve pure water. Fortunately there is a solution to these problems. It is a technology that is not only capable of removing a very wide variety of contaminants in just one step, but is simple, cost-effective, and environmentally friendly. That is use of solar energy.

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Chapter-2

SOLAR STILL Solar purification is a tried and true technology. The first known use of stills dates back to 1551 when it was used by Arab alchemists. Other scientists and naturalists used stills over the coming centuries including Della Portal (1589), Lavoisier(1862), and Machete (1869)[3]. The first "conventional" solar still plant was built in 1872 by the Swedish engineer Charles Wilson in the mining community of Las Salinas in what is now northern Chile (Region II). This still was a large basin-type still used for supplying fresh water using brackish feed water to a nitrate mining community. The plant used wooden bays which had blackened bottoms using logwood dye and alum. The total area of the distillation plant was 0.278 square meters. On a typical summer day this plant produced 1.59 kg of distilled water per square meter of still surface, or more than 15.59 litres per day. Solar water Distillation system also called “Solar Still”. Solar Still can effectively purify seawater & even raw sewage. Solar Stills can effectively removing Salts/minerals {Na, Ca, As, Fe, Mn} ,Bacteria { E.coli, Cholera, Outlines}, Parasites ,Heavy Metals & TDS. Basic principal of working of solar still is “Solar energy heats water, evaporates it (salts and microbes left behind), and condenses as clouds to return to earth as rainwater”.

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Chapter-3

WORKING OF SOLAR WATER PURIFIER 3.1.Working principle: The basic principles of solar water distillation are simple yet effective, as distillation replicates the way nature purifies water. The sun’s energy heats water to the point of evaporation. As the water evaporates, purified water vapour roses, condensing on the glass surface for collection. This process removes impurities such as salts and heavy metals, as well as destroying microbiological organisms. Is a passive solar distiller that only needs sunshine to operate; There are no moving parts to wear out. The distilled water from a still does not acquire the “flat” taste of commercially distilled water since the water is not boiled (which lowers pH) . Solar stills use natural evaporation, which is the rainwater process. This allows for natural pH buffering that produces excellent taste as compared to steam distillation. Solar stills can easily provide enough water for family drinking and cooking needs.

Solar distillers can be used to effectively remove impurities ranging from salts to micro organisms and are even used to make drinking water from seawater. Stills have been will received by many users, both rural and urban, from around the globe. Solar distillers can be successfully used any where the sun shines.

The solar stills are simple and have no moving parts. They are made of quality materials designed to stand- up to the harsh conditions produced by water and sunlight. Operation is simple: water should be added (either manually or automatically) once a day through the stills supply fills port. Excess water wool drain outs of the overflow port and this will keep salts from building up in the basin. Purified drinking water is collected from the out put collection port

3.2.Supply fills ports: Water should be added to the still via this port. Water can be added either manually or automatically. Normally water is adds once a day (in the summer it’s normally best to fill in the late evening and the in the winter the early morning). Care should be taken to add the water at a slow enough flow rate to prevent splashing onto the interior of the still glazing or overflowing into the collection through.

3.3.Overflow port: Once the still basin has filled, excess water will flow out of this port.recommonds three times daily distilled water production to be allowed to overflow from the still on a daily basis to

11 prevent salt build-up in the basin if flushed on a daily basis, the overflow water can be used as appropriate for your feed water.

3.4.Distilled output collection port: Purified drinking water is collected from this port, typically with a glass collection container. still that are mounted on the roof can have the distillate output piped directly to an interior collection container. For a newly installed still, allow the collection through to be selfcleaned by producing water for a couple of days before using the distillate output.

3.5.Solar still back ground: Solar distillation is a tired and true technology the first known issue of still dates back to 1551 when it was used by Arab alchemists. Other scientists and naturalists used stills over the coming centuries including Delia Posta (1589), lavisher (1862), and mascot (1869). The first conventional solar still plant was built in 1872 .by the Swedish engineer Charles Wilson in the mining community of last Salinas in what is now northern Chile (region //).this still was a large basin –type still used for supplying fresh water using brackish feed water to a nitrate mining community the plant used wooden bays which had blackened bottoms using logwood dye and alum. The total area of the distillation plant was 4700 sq. meter of still surface, ore than 23000 till / day. This first still plant was in operation for 40 yrs. Over the past century, literally hundreds of solar still plants and thousands of individual stills nice been built around the world. Still have built upon years of still research and development and use only food grade material and are the static of the art for commercial solar still Distillation.

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Chapter-4

TROUBLESHOOTING

4.1.WHITE CRUSTY BOTTOM INSIDE PURIFIER OR PURIFIER DOES NT LOOK CLEAN INSIDE: You need to clean the purifier because it has either run dry and calcium carbonate has been left behind or else build-up of salts/minerals has occurred due to improper maintenance and irregular flushing. Take of f the glass, GENTLY scrub (with a soft kitchen dish scrubber) the bottom and sides with vinegar, rinse and replace glass. You may wish to do this once/ year (or more often if you wish) any way. Make sure to dump out all the old water first. Some of the contaminated water will probably splash on the underside of the glass or into the trough so make sure to let the purifier run for 2-3 years before drinking the water so it will self clean.

4.2.LARGE DROPS OF WATER ON UNDER SIDE OF GLASS OR NOT GETTING MUCH PURIFIED WATER OUT: If there is no water inside the purifier, or the sun shines inside when there is no water inside, it will heat up the purifier like an oven and the mild steel liner will out gas.outgasing but causes the purifier to loss some production/efficiency .this is due to the large drops that collect and tend to drop back into the water basin instead of sliding smoothly down the glass and into the trough as it is supposed to . You may (since you have the glass off any way) wish to clean the purifier as prescribed above at the same time. Make sure to let the still run with new water in it for 2-3 years before drinking the water so it will self cleaned. 4.3.BROKEN GLASS: you can probably pay about 200-300 Rs,for a piece of DOBLE STRENGTH glass from your local glass supply house, or you can order a piece or TEMPERD glass 9 preferred since it is safety glass and doesn’t cut children or adults as readily if it does brek,also it is less likely to break as it is stronger than regular or even double strength glass from solar . 4.4.BUBBLES IN LINER: sometimes due to manufacturing the M.S.liner will gear a bobble or two (on very rear occasions).this will not harm to your purifier in any way, nor should it reduce output of purified water.

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Chapter-5

SOLAR ENERGY Every day, the surface of planet earth is blasted with so much solar energy that, if harnessed, 60 second’s worth could power the world’s total energy requirements for one year. The sun is a colossal fusion reactor that has been burning, for more than 4 billion years. In just one day, it provides more energy than the current human population would consume in 27 years. By some estimates, the amount of solar recitation striking the earth every 72 hours is equivalent to all energy stored in the planet’s coal, oil, and natural gas reserves.

Solar radiation is a free and unlimited natural resource, yet converting it into an energy sources is a relatively new idea. Using solar power for heat seems simple enough today , but it wasn’t until 1767 that Swiss scientist Horace de assure built the first thermal solar collectors . He used his solar collator to heat water and cook food. It wasn’t until 1891 that the first commercial patent for a solar water heater was awarded to US inventor clearance Kemp. The patent right to this system were later purchased by two California executives who by 1897, had installed the solar – powered water heaters in one- third of the homes in Pasadena, California. Solar energy has great potential for providing clean and unlimited electricity in May regions of the world. This renewable resource has largely been ignored by many US energy providers because there has been little economic motivation due to the abundance of cheap coal, and oil, corporate shareholders wants their profits today, not sometime in the distant future. In the last few decades, however, global energy demand has surged, as have the environmental problems associated with burning coal and oil and the storage of nucleargenerated radioactive waste. In the late 1990s, more governments, utilities, and corporations were embracing renewable energy sources as environmentalists, consumers, and voters pressure them to do so. More importantly, many consumers are willing to pay for “green energy” so suppliers see future profit in non-polluting renewable energy production. Some governments and energy suppliers have been slow to recognize the potent ional of solar power. Historically, research and development in photovoltaic’s has progressed erratically, in short- lived during the 1973-1974 oil embargo. By the late 1970s, energy companies and government agencies wear investing in the PV industry, and acceleration in module development took place. But solar power remained far behind oil, coal, nuclear, and other non rewable energy sources. Serious interest in photovoltaic’s increased again during the 1990s after several military conflicts in the oil Rich Persian gulf

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Chapter-6

SOLAR RADIATION Solar energy is the electromagnetic energy or radiation emitted by the sun. solar energy arrives at the our of the earth’s atmosphere .part of this radiation is reflected back to space,

15 part is observed by the atmosphere and re emitted and part is state side by atmospheric particle as a result only about, two thirds of the suns energy reaches the surface of the earth.

6.1.Solar radiation outside the earth’s atmosphere The cherictirstics of the suns energy available outside the earth’s atmosphere are first considered. The sun is a large sphere of hot gases the heat being generated by various kinds of fusion reactions. Its diameter is 1.39*10^6 Km, while that of the earth is 1.27*10^4 Kms.the mean distance between the two is 1.50 *10^3 Kms.all the sun is large ,it substance an angle of only 32 min at the earth surface .this is because it is also at a very large distance .thus the beam radiation received from the sun of the earth is almost parallel, the brightness of the a sun varies its centre to its edge. However for engineering calculations, it is customary to assume that the brightness all-overs the solar disk is uniform as viewed from the earth, the radiation coming from the sun appears to be essentially equivalent to that coming from a black surface at 5763 K.

6.2.BEAM OR DIRECT RADIATION: Solar radiation received at the earth surface without change of direction is called beam or direct radiation .it is if form of straight rays that the unscathed by the atmosphere.

6.3. SOLAR RADIATION AT THE EARTH SURFCE: Solar radiation is received at the earth surface after being subjected mechanisms of attenuation, reflection and scattering at the earth atmosphere. The radiation recived without changed direction is called beam radiation ,while that received after its direction as been changed by scattering and reflection is called diffused radiation .the sun of the beam and diffuse radiation flux is referred to as total radiation or global radiation. Although extensive studies have been made on the various mechanisms which reduce the Quantity of radiation being received at the earth surface is in general not possible to predict to a reasonable degree of accuracy the amount which might be expected on the ground .thus the designer of solar process equipment has to taker resources to one of the following options. a. Make measurements over a period of time at the location in questions where solar equipment is to be installed. B.use measurements available for some other locations whose climate is known to be reasonable similar to the location under consideration. C.use epical predictive eqns which link the values of solar radiation with other metrological parameters whose values are known for the location under consideration. Examples of such parameters are the no of hours of sunshine received every day the precipitation that could cover etc.

6.4. MEASUREMENT OF SOLAR RADIATION: Solar radiation can be measured by the following instruments 1. Pyheliometer 2. Pyranometer

16

I.

II.

Pyheliometer: it is an instrument which measure beam radiation in contact to a pyranometer,the black sensor disk is located at the base of a tube whose axis is aligned with the direction of the rears rays. Thus diffuse radiation is essentially blacked from the sensor surface. Pyranometer:a pyranometer is an instrument which measure the either global or diffuse radiation over a hemi spherical field of view. Basically the pyranometer consists of a black surface which heats up when exposed to the solar radiation.

6.5. SOLAR ENERGY STORAGE: Solar energy is intermittent energy source and must be stored for lateral use solar storage may permit to produce uniform electrical or thermal energy is improves the reliability solar thermal and electrical sytem.soalr storage system provides adequate input energy to meet the load demand. Methods of storing solar energy: The storage system store energy when the collected amount is in excess of the requirement and discharges energy when the collected amount is in adequate. The different methods of storing solar energy are: 1. Thermal storage A. Sensible heat B.latent heat 2. Chemical storage A. Thermal chemical storage B.fuel C.hydrogen storage 3. Mechanical storage A.fly wheel B.compressed air C.hydro electric storage 4. Electric storage A. Capacity storage B.battery storage C.electromagnetic storage

6.6.SOLAR CONSTANT:

17 The rate at which solar energy arrives at the top of atmosphere is called solar constant (Isc).solar constant may be defined as the amount of energy received in unit time on a unit area proportional to the suns directions at the mean distance of the earth from the sun. The rate of arrival solar radiations varies throughout the year. The standard value expressed by NASA (NATIONAL AERONAUTICS AND SPACE ADMINISTARTION) is 1.353 KW/m2.

Chapter-7

SOLAR WATER PURIFICATION SYSTEM

18 Solar water purification is of the simplest and most effective methods of purifying water. Solar water distillation replicates the way nature purifies water. The sun’s energy beats water to the point of evaporation. As the water evaporates purified water vapour rises, condensing on the glass surface for collection. This process removes impurities such as salts and heavy metals, as well as destroying microbiological organisms. The end result is water cleaner than the purest rainwater. Only solar energy is required for the still to operate. There are no moving parts to wear out.

The number of systems designed to fitter or purity water has increased dramatically in recent years. As water supplies have increased in salinity, have been contaminated or have experienced periods of contamination, people have lost trust in their drinking water supply. Water filtration systems can be as simple as a filter for taste and odour to complex water treatment systems can remove more impurities but they are also the most expensive to operate and required increased maintains.

Fig7.1.. purification system

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10 watt SOLAR PANEL SPECIFICATION

power(w) open circuit voltage short circuit current max.power voltage max.power current cell-type frame type junction box Length Width Depth Weight connector Fig.7.2.solar panel

10 watts 22.30 voc 0.58 ISC 18.70 vmp 0.54 IMP mono-crystalline Silver Yes 13.78 inches(350.01)mm 11.42 inches(290.07)mm 0.98 inches(24.89)mm 3.31 lb (1.50)kg battery clamp

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Applications of solar energy 1. heating and cooling of residential building 2. solar water heating

3. solar drying of agricultural and animal products 4. solar distillation on a small community scale

5. Salt production by evaporation of sea water of inland brines. 6. solar cookers

7. solar engines for water pumping

8. food refrigeration

9. bioconversion and wind energy which are indirect source of solar energy

10. solar furnaces

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Water in atmosphere • •

In gas form-absorbs long wave radiation (green house gas) and stores latent heat. In liquids and solids forms –reflects and absorbs solar radiation.

Phase and transitions

Solid ice in ocean and atm clouds

Liquid- water in ocean and atm clouds

Gas vapours In atmosphere(humidity)

Fig.7.3.water in atmosphere

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What is difference between boiling and evaporation?

Temperature

Boiling takes place at 100 degree Celsius ,but evaporation takes place at 40 degree Celsius

Bubbles are formed during boiling ,but in evaporation

Bubbles

Gas

Gas formed in boiling water is called steam and gas formed during evaporation is called water vapour Fig.7.4.differnce between boiling and evaporation

What is pressure? The pressure in a fluid is defined as “the normal force per unit area exerted on a imaginary or real plane surface in a fluid or a gas. The eqn for pressure p=F/A Where, P=pressure lb/in2 (psi) N/m2 or kg/ms2 (pa) F=force (n) A=area (in2, m2)

What is gauge pressure?

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A gauge is often used to measure the pressure difference between a system and the surroundings atmosphere. This pressure is often called the “gauge pressure”. It can be expressed as; Pg=Ps-Patm. Where, Pg=gauge pressure. Ps=system pressure. Patm=atmospheric pressure.

What is atmospheric pressure?

Atmospheric pressure is pressure in the surroundings air at – or “close” to the surface of the earth .the atmospheric pressure vary with temperature and altitude above sea level.

The main conclusions are :1atm=1.0325bar=14.696psi=760mm of Hg = 10.33Mh2o=760torr=29.92 in Hg=101.3mbar=1.0332kg/cm2=33.90ftH2O.

SOME ALTERNATIVE UNITS OF PRESSURE:• • • • • •

1 bar=100000 pa. 1 mille bar=100 pa 1 atmosphere=101325 pa 1 mm of Hg =133 pa 1 inch Hg=3386 pa 1 Atm pressure=760 torr=14.696 pounds per sqr inch (psi).

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What is Evaporation? Evaporation is a type of vaporisation of a liquid that only occurs only on the surface of a liquid. The other type of vaporisation of boiling, which instead, occur within the entire mass of the liquid.

What is convection? Convection is a form of heat transfer, as is the process of radiation, which we examined. Convection takes place in liquids and gases and distinguishes them from solids.

R of the air constant=287 J/kg k P=mRT m=mass of unit volume. R=universal gas constant.

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Chapter-8

DESIGN OF SOLAR WATER PURIFICATION PLANT

Construction of Solar water purifier:

26

I.

Fig.8.0.a.design of solar water purification plant

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fig.8.0.b. Proposed Model of Solar Distillation System

28 8.1.

Details of Different Parts of the System

8.1.1. Still Basin: It is the part of the system in which the water to be distilled is kept. It is therefore essential that it must absorb solar energy. Hence it is necessary that the material have high absorbtivity or very less reflectivity and very less transitivity. These are the criteria’s for selecting the basin materials. Kinds of the basin materials that can be used are as follows: 1. Leather sheet, 2. Ge silicon, 3. Mild steel plate, 4. RPF (reinforced plastic) 5. G.I. (galvanised iron).

Fig.8.1.1.STILL BASIN

29 We have used blackened MILD STEEL sheet (K= thermal conductivity= 300W/m0C) (8mm thick).( SIZE:: BOX30×18 inche2 OF M.S.)

8.1.2.Top Cover: The passage from where irradiation occurs on the surface of the basin is top cover. Also it is the surface where condensate collects. So the features of the top cover are: 1) Transparent to solar radiation, 2) Non absorbent and Non-adsorbent of water, 3) Clean and smooth surface. The Materials Can Be Used Are: 1.Aluminium frame, 2.Glass, We have used glass thickness (8mm).

Fig. 8.1.2. TOP COVER

30 8.1.3.Channel: The condensate that is formed slides over the inclined top cover and falls in the passage, this passage which fetches out the pure water is called channel. The materials that can be used are: P.V.C., 2) G.I. , 3) RPF . We have used P.V.C channel (figure.4)(size:: 4.5’ X 1” cm).

Fig.8.1.3 . CHANNEL

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8.1.4.Side Walls: It generally provides rigidness to the still. But technically it provides thermal resistance to the heat transfer that takes place from the system to the surrounding. So it must be made from the material that is having low value of thermal conductivity and should be rigid enough to sustain its own weight and the weight of the top cover. Different kinds of materials that can be used are: 1) wood, 2) concrete, 3) M.S. sheet 4) RPF (reinforced plastic). For better insulation we have used composite wall of M.S .sheet (inside) and (outside). (Size:- 8 mm thick, 30×18 inch2).

Fig.8.1.4. SIDE WALL

32

8.1.5.Supports for Top Cover: The frame provided for supporting the top cover is an optional thing. I.e. it can be used if required. We have used fibre stick as a support to hold glass (size:: 31.9 inch 18.3 inch). The only change in our model is that we have to make the model as vacuumed as possible. So we have tried to make it airtight by sticking tape on the corners of the glass and at the edges of the box from where the possibility of the leakage of inside hot air is maximum.

Fig.8.1.5.Working model of solar distillation system

33

Chapter-9

MATERIALS TO BE USED
The following factors are to be considered to use a material • • • • • • •

Selection of material Suitability of materials for service conditions. Size and shape of the part. Condition of loading to which the part is subjected. Manufacturing requirements. Availability of material cost. Properties of material.

9.1.PROPERTIES Strength:- it is defined as the capacity to resist external loads under given conditions. Modulus of elasticity:- it is ratio of stress to the strain within the elastic limit, the metal with high modulus of elasticity possess high stiffness. Ductility:- it is the ability of the material to deform under tensile load. Malleability:- it is the ability of material to be deformed under compressive load. Brittleness:- it is the ability of the material fracture with every little deformation. Hardness:- it is the ability of the material to resist abrasion, scratching or indentation. Resilience:- it is the ability of the material to store energy within its limit. Toughness:- it is the ability of the material to absorb energy before fracture. Fatigue strength:- the maximum stress at which the material will operate indefinably without failure. Creep:- the slow and progressive of the material with time cost is called creep. Mach inability:- the ease with a given material may be worked with machine is called mach inability. 9.2. about mild steel: Carbon steel is also called plain carbon steel, it is a metal alloy. A combination of two elements iron and carbon, where other elements are present in quantities too small to affect the properties. The only other alloying elements allowed in plain-carbon steel are manganese (1.65%max), silicon (0.60% max), and copper (0.60% max).steel with a low carbon content has the same properties as iron, soft but easily formed. As carbon content rises the metal higher carbon content lowers the steel melting point and its temperature resistance in becomes harder and stronger but less ductile and more difficult to weld. Generally carbon contents influences the yield strength of steel because they fit into the interstitial crystal lattice sites of the body-centred cubic arrangement of the iron molecules..The interstitial

34 carbon reduces the mobility of dislocations. Which intern has a hardening effect on the iron. To get dislocations to break away. This is because the interstitial carbon atoms cause some of the iron BCC lattice cells to distort. The term mild steel is also applied commercially to carbon steels not covered by standard specifications. Carbon content of this steel may vary from quite low levels up to approximately 0.3%. Generally commercial mild steel can be accepted to be readily wieldable and have reasonable cold bending.

Properties:But to specify mild steel is technically in appropriate and should not be used as a term engineering .approximately 0.05-0.15% carbon content for low carbon steel and 016-029% carbon content for mild steel (e.g.AISI 1018 STEEL). Mild steel has a relatively low tensile strength ,but it is cheap and malleable, surface hardness can be increased through carburizing. Mild is the most common form of steel as its price is relatively low while it provides material properties that are acceptable for many applications. Mild steel has low carbon content (up to 0.3%) And is therefore neither extremely brittle nor ductile. It becomes malleable when heated, and so can be forged. It is also often used where large amount of steel need to be formed. For example as structural steel. Density of this metal is 7,861.093kg/m3 (0284lb/in3) the tensile strength is maximum of 500MPa (72,500 psi) and it has a young’s modulus of 210GPa. Medium carbon steel: - approximately 0.30-0.59% carbon content (e.g. AISI 1040 steel).balances ductility and strength and has good wear resistance, used for large parts, forging and automotives components. High carbon steel: - approximately 0.6-0.99%carbon content .very strong used for springs and high –strength wires.

Ultra-high carbon steel: -

approximately 1.0-2.0%carbon content. Steels that can be tempered to great hardness .used for special purpose like (non-industrial purpose) knives, axles or punches. Steels are often wrought by cold-working methods, which us the shaping of metal through deformation at a low equilibrium or met stable temperature.

35

Chapter-10

DESIGN CALCULATIONS FOR SOLAR WATER PURIFIER 1. Daily hours of sunlight=5hours /day a. =5hours/day × 3600 sec/hour b. =18,000 sec/day

2. ῃ still=ῃ channel=60% 3. daily global solar irradiation(G)=1.0kw 4. the solar energy obtained from the solar collector(S)=1.2kw,based on the ˝MODEL RA 240 SOLAR MAX by consolair.in.˝

• Evaporation rate can be calculated by:-

1. Q=(ῃ CHANNEL ×S+ ῃ STILL×A×G)/(heat of vaporisation) 2. Q=(60%×1×10^3×(316-313) ×18000)+(60%×0.278×0.001×10^6×18000 /(2.27×10^6) a. =15.59 L/day /m2

Where, 1. heat of vaporisation of water =2.27MJ/L 2. Q is the daily output of distilled water(litre/day) 3. ῃstill is the efficiency of the still

36 4. ῃ channel is efficiency of the flow channel mani fold, as the fraction of the energy transferred to the water to energy collected from the solar energy collector. 5. G is the daily global solar irradiation approximatly1000 watts/sq m for surface i. Approximately 18MJ/m2 6. A is the still surface area (perpendicular to the sunlight) 7. S is the thermal energy obtained from solar ENERGY COLLECTION. It can be calculated by using enthalpy (∆H). ∆H=Hf-Hi=m.Cp(T2-T1)

Where, •

ΔH is the enthalpy change

•

H final is the final enthalpy of the system expressed in (MJ)

•

H initial is the initial enthalpy of the system

•

M is the mass flow rate out of the air flow(kg/s)

•

Cp is the specific heat of air (MJ/kg/k)

•

T2 is the flow outlet temperature of solar energy collection in Kelvin scale.

•

T1 is the inlet temperature of the solar energy collection in Kelvin scale.

37

Chapter-11

TECHNICAL REPORT 11.1Results and Discussion Experiment is performed from 10:00am to 04:00pm in summer season.

Time

Outside temp in 0C

Inside temp (water) in 0C

10.00AM

30 0C

40 0C

11.2Readings taken for still: Table 1 represents the reading taken for solar still. Table. Reading for Solar Still

38 10.45AM

32 0C

43 0C

11.30AM

34 0C

47 0C

12.15PM

36 0C

50 0C

1.00 PM

38 0C

53 0C

1.45 PM

40 0C

56 0C

3.00 PM

41 0C

59 0C

3.45 PM

42 0C

63 0C

for solar still

11.3. Observations: • • • • •

Time taken for drop to come to channel = 35Minutes Time taken for drop to come out of channel = 10 min Amount of brackish water poured initially = 24 litre Amount of pure water obtained at the end of the exp. = 15.59 L/day/m2 Temperature of the condensate = 43 0C

11.4. Tested of purified water 1. Measuring the PH value of the purified water by using PH meter. 2. Determined the PH value of the purified water is “7”.

3. Density of the pure water is “1” 4. Boiling point 100 0C.

fig.11.2 .1 .reading

39

Chapter-12

CONCLUSION Finally, we concluded that this device need to be required some installations like 1. Temperature sensor 2. Pressure sensor/gauge 3. Ionic exchanger Apart from these, this purification system is more advantageous than the normal solar distillation systems. The collected distillate from this system is very much suitable for modern engineering applications like in chemical laboratories, pharmaceutical industries, maintenance of vehicle batteries, domestic purpose and so on. This solar water purification system is portable and maintenance free (cleaning is required through), it is an inexhaustible fuel sources, doesn’t cause any pollution. it is an excellent supplement to other renewable sources. The collected water from the device as better taste when compared to rain water because it doesn’t boiled.

40

Chapter-13

BIBILOGRAPHY 1. 2. 3. 4. 5. 6. 7. 8. 9.

Renewable energy resources/Tiwari and Ghosal/Narosa Non conventional energy sources/G.D.Rai Renewable energy sources/Twidell and Weir Solar energy/Sukhatme Solar power engineering/B.S.Magal Frank Kreith and J.F.Kreith Principals of solar energy/Frank Kreith and John F .Kreider Non conventional energy /Ashok V.Desai/Wiileyeastern Non conventional energy systems/K.Mittal /Wheeler Renewable energy technologies /Ramesh and Kumar/Narosa