Saturday, January 30, 2016

TRAPEZOIDAL SOLAR COOKER (Advancement to Increase Sun Rays Absorption)


ABSTRACT -

The cooker provides an improved panel which works as tracking system in this cooker helping to eliminate the tracking arrangement which reduces human effort. The significance of these panels is that they replace the tracking system which reduces cost and reduces human effort of frequent adjustment of mirror, reducing the weight. A novel focus arrangement includes four reflecting panels for gathering the sun’s rays and focusing them into a zone so as to distribute the heat for effective cooking without burning the food or the containers .The cooker folds into a relatively small package for storage or transportation. It can be assembled quickly and easily. The cooker in its small, folded condition is highly portable, but is easily and quickly set up for use. Further means are provided for holding and cooking various types of food including liquids, solids, etc. The device provides a single glazed glass reflector having a relatively short focal length and which provides focusing of the reflected rays into a zone so as to provide effective heating of the cooking area without overheating.

KEYWORDS : Trapezoidal collector, glassing material, solar deflection per hour, experimental analysis.

 INTRODUCTION
1.1.         CURRENT SCENARIO -
In the past decade there has been a significant increase in the economic progress and human life style. Even though it gives pleasure to us, there is a another major problem to be resolved are the great environmental issue, increase in the average temperature of the universe (global warming) and energy security because of the severe utilization fossil fuels such as coal, petrol and diesel which will be exhausted within the few decades.
The vise option for the above mentioned problem is going for renewable energy. Renewable energy is energy which comes from natural resources such sunlight, wind, rain, tidal, and geothermal heat, which are renewable (naturally replenished). The solar energy has a prime contribution in generation of other types.
The electricity bill has also gone up due to demand. But we need a large amount of hot water at a wide range of temperature for home and industrial application. By harnessing the solar energy we can make a hot water. It is well proved in solar water heater. In India the government and other social organization are instructing and supporting the people to use and implement the solar energy in various application

1.2.         SOLAR POWER IN INDIA -
India is both densely populated and has high solar insulation, provided an ideal combination for solar power in India. With about 300 clear sunny days in a year, India’s theoretical solar power reception, just on its land area, is about 5 PWh/year (i.e. =5000 trillion kWh/m2 with about 2,300-3,200 sunshine hours per year, depending upon location. This is far more than current total energy consumption. For example, even assuming 10% conversion efficiency for PV modules; it will still be thousand times greater than likely electricity demand in India by the Year 2015.


1.3.         SOLAR RADIATION AT THE EARTH -
From the point of view of utilization of solar energy we are more interested in the energy received at the earth’s surface then in the extra terrestrial energy. Solar radiation received at the surface of the earth is entirely different due to various reasons. The types of solar radiation are as follows:

1.3.1.      Beam or Direct Radiation -
Solar radiation that has not been absorbed or scattered and reaches the ground directly from the sun is called direct or beam radiation, most of the energy from sun belongs this category.

1.3.2.      Diffuse Radiation -
It is a solar radiation received from the sun after its direction has been changed by reflection and scattering by the atmosphere.

1.4.         UTILIZATION METHOD -
The Fig.1 depicts the different types of utilization of solar radiation. The solar energy causes for all another energy sources also such as wind, biomass, and geothermal and tidal energies. These are indirect usage, the direct utilization method are as follows:
·         Electricity generation through photovoltaic cells.
·         Solar thermal capture

LITERATURE REVIEW

2.1.         SOLAR COOKING WHY?
Because you can cook your food without electricity, gas, fire etc. Listed here are some major advantages and benefits of solar cooking. 
·         First of all you may have realized that the energy from the sun is free.
·         Second it uses none of our limited natural resources that are currently being used for other energy applications in our modern world... It is good for our environment.
·         Third it can be a more healthy way of preparing our foods for consumption as opposed to gas, smoky open fire, microwave etc. because it uses the natural power of the sun's energy.
And, best of all, it preserves more of the natural nutrients of the foods by cooking at slower and lower temperatures. And one of the most important reasons for using solar cooking: it is giving people around the world a hand up. It is a vital instrument for a more comfortable, healthy and better way of life by giving them a feasible alternative to the costly, time consuming chore of cooking over and tending fires, as well as the dangerous and time consuming necessity of scavenging for cooking fuels in desolate and dangerous country sides distressed by famine, war and political turmoil.
2.2.         DOESN’T IT TAKE LONGER TO COOK USING SOLAR ENERGY?
  • Yes, it can take longer with some foods, but with others the time required is almost as quick and efficient as traditional cooking methods.
  • Solar cooking can be compared to the "slow and low" temperature of Dutch oven or Crockpot methods of cooking.
  • Depending upon the time of day and even the time of year, your cook time will vary.
  • The biggest advantage to solar cooking is that you can leave it to cook on its own without the need to constantly tend it. It's almost impossible to burn the food.
There is no movement of air in a solar cooker, allowing food to stay moist and tender and flavorful.
Sun-baked roasts are tastier and more succulent, and sun-baked bread has unparalleled taste and texture.
Temperatures in a solar oven rise slowly and evenly, allowing complex carbohydrates time to break down into simple sugars, emanating subtle natural flavors.
The even temperature of the solar oven prevents burning, so you do not need to stir your food while it is cooking.


2.3.         CAN SOLAR COOKER REPLACE THE CONVENTIONAL METHOD OF COOKING?
For some it can; and has done so...
Granted, there are some limitations with a solar cooker, especially when it comes to preparing complex and structured recipes and of course weather and some locations also are factors. But, it is possible to cook every day that there is sunshine by planning and organizing ones meals ahead of time in order to take advantage of the sun’s energy as it is available (I have found though, by much use and experimenting, that the amount and variety of foods and dishes that can be cooked in a solar cooker are quite substantial. I have cooked everything from cookies and cakes to pastas and pizza, chickens and roasts to corn on the cob and baked beans; there really is no limit if you experiment with each dish.)
 


 EXPERIMENTATION
3.1.         EXPERIMENTAL PROCEDURE -
The working model is being tested in two different stages. In the first stage the solar cooker is tested without the trapezoidal reflective surfaces. Then in the second stage the trapezoidal solar cooker is tested with a full scale model of the adiabatic can is noted down for every 30 minutes in both stages and the readings are tabulated. The both solar cooker is tested at the mid day (12.00 PM- 1.30PM). The conventional mercury thermometer has been used to measure the temperature of the water in the adiabatic can.
Experimental Results -
Tabulation
CALCULATION

4.1.         FORMULA USED -
                      Q = M Cp ΔT
Where, Q = heat transferred in KJ
M = mass of the water in liters.
ΔT = temperature difference in ºC
4.2.         ANALITICAL -

First Trial

Total heat absorbed by Can by conventional solar cooker
Q = M Cp ΔT
   = 0.5×4.19× (49.5-29)
   = 42.9475 KJ
Total heat absorbed in tank by proposed solar cooker
Q = M Cp ΔT
   = 0.5×4.19× (53-29)
   = 50.28 KJ
Increased percentage of total heat transferred with our proposed cooker
                                                                                                                                
                                  =  17 %
Second Trial

Total heat absorbed by Can by conventional solar cooker
Q = M Cp ΔT
   = 0.5×4.19× (51-29)
   = 46.09 KJ
Total heat absorbed in tank by proposed solar cooker
Q = M Cp ΔT
   = 0.5×4.19× (54-29)
   = 52.375 KJ

Increased percentage of total heat transferred with our proposed cooker

                                                            
      =  13.6 %
Average percentage of total heat transferred with our proposed cooker

                            
         =  15.3 %


 4.3.          EXPERIMENTAL RESULT AND DISCUSSION -

Experiments were conducted in two different stages. In first stage the experiment were conducted without trapezoidal surfaces of cooker. Then in second stage the heater was tested with proposed solar cooker. For better accuracy, the experiment was tested in two consecutive sunny days with both stages.
The both experiment were conducted on 12, 13 may 2012. The can was filed with 0.5 liters of water with initial water temperature of 29ºC. The cooker was then exposed to solar radiation from 12 am to 1.30 pm. The readings were tabulated for every 30 minutes. Maximum water temperature was found to be 51ºC in convectional solar cooker and 54ºC in proposed solar cooker. As it can be clearly seen from the graph, the absorbed temperature of the water by newly designed solar cooker is higher than the temperature of water by conventional solar cooker. The fig. 1 and Fig. 2 clearly shows that proposed cooker could absorb more heat than the conventional cooker. It has calculated that the heat collective efficiency of our proposed design is 15.3% higher than conventional cooker.


5.    ADVANTAGES OF SOLAR COOKERS -

The biggest advantage of solar cookers is their eco-friendliness. By using a solar cooker, you can let go of your dependence on gas or electricity. You can maintain better air quality indoors and reduce the amount of carbon monoxide emissions. You can also enjoy cooler temperatures indoors and conserve more fuel by reducing the need for air conditioning.
Solar cooking is free to use once you have bought the cooker itself. For the purpose of operation, all you need is sunlight. You can save a significant amount of money over the long term. As a result, solar cookers are being used increasingly in different parts of the world, especially in poorer communities with limited access to fuel and power.
The quality of food cooked in a solar cooker is also notable. There is no danger of burning food and flavors remain intact. Solar cookers can be used for grilling, roasting and baking food. Baked foods also retain moisture and softness if the solar cooker is used properly. Solar cookers are easily accessible to people around the globe. It is very easy to build one from scratch as well.
Commercial versions of solar cookers fall into three main categories–box cookers, parabolic cookers and panel cookers. Of the three, parabolic solar cookers are the most advanced and efficient. Some solar cookers even have the ability to automatically track the sun’s rays so as to maximize the heat produced in the cooker.

6.    DRAWBACKS OF SOLAR COOKERS -

Cooking with solar cookers requires sunlight. This makes the process difficult during winter months and on rainy days. Cooking also takes a significantly longer time as compared to conventional methods. Users must schedule their cooking time and maximize the use of sunlight. As a result, preparation for cooking must start early in the morning so that the food can be placed in the cooker by noon.
Solar cookers are not as efficient at retaining heat as compared to conventional cooking devices. Factors such as wind, rain and snow can seriously hinder the operation of a solar cooker. In such weather conditions, even after the food is cooked, it will lose its warmth very quickly. For most homes, a solar cooker by itself is not a reliable means of cooking. You will need a backup cooking appliance that operates on gas or electricity. It will come handy when the weather is unfavorable and when the sun is hidden.
Although solar cookers are easy to build and use, there is a risk of accidental injury or burns if the appliance is not used properly. Eyesight can also be damaged if the concentrated beams of sunlight are reflected back into the eyes from the solar cooker. The use of safety precautions and protective materials is necessary.


7.    CONCLUSION -

The existing solar cooker is observed and the modification is made by incorporating the Trapezoidal Reflecting Surface to the flat Surface. The obtained result shows the collective efficiency of our proposed design in 15.3% higher than conventional solar cooker. The entire system is fabricated with commonly available materials. It is expected that if designed with advanced materials, efficiency may be increased at higher rate. Due to financial constraints we have not used tracking mechanism in our set up. It is believed that further efficiency of Trapezoidal solar cooker can be increased by adding the appropriate solar tracking system.

8.    RERERENCES

9.    PHOTOS OF PROJECT







Mr. KONAL
Mechanical Engineer
Ph. 09423632068
Director & Founder
ProBotiZ ... Steps Into Virtual Techniz
ProBotiZ Group
Nagpur (M.S), India – 440017


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