Design And Construction Of A Parabolic Solar Cooker

ABSTRACT

The use of renewable energy, particularly solar energy, is increasing day by day to promote its contribution to national economy. Solar energy can be used in heating, drying, cooking and also for generating electricity. In this paper the design, construction and performance test of a parabolic dish solar (PDS) cooker is discussed. The cooker having an aperture diameter of 106 cm and focal length of 54 cm was designed, constructed and the performance was tested. Plane mirror was used as reflecting material in the cooker. The maximum temperature inside the cooking pot was found to be 97°C.As performance test rice and dal were cooked in various amounts at different days and times. Experiments showed that the temperature inside the cooker varies with the available solar radiation. The cooker could cook 300 gm rice and 100 gm dal within 40 minutes at an available radiation level of 320 -390 W/m². An economic analysis of the cooker was performed and it showed a payback of 16 months, which is realistic and very promising.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND AND OVERVIEW OF THE STUDY
• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• SCOPE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• PURPOSE OF THE PROJECT
• APPLICATION OF THE PROJECT
• ADVANTAGES OF THE PROJECT
• DISADVANTAGES OF THE PROJECT
• LIMITATION/PROBLEM OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0     LITERATURE REVIEW
2.1     OVERVIEW OF THE STUDY
2.2     REVIEW OF DIFFERENT TYPES OF SOLAR COOKER
2.3     HISTORICAL BACKGROUND OF SOLAR COOKING AND FUTURE PROSPECTS
2.4     OVERVIEW OF PARABOLIC REFLECTORS

2.5     REVIEW OF PARABOLOIDAL REFLECTORS

2.6   HISTORICAL BACKGROUND OF SOLAR COOKING AND FUTURE PROSPECTS

CHAPTER THREE

3.0      METHODOLOGY

3.1     DESIGN DIAGRAM

3.2   PRINCIPLES OF THE PROJECT

3.3      OPERATION OF THE SYSTEM

3.4      SELECTION OF MATERIALS USED

3.5      DATA COLLECTION

CHAPTER FOUR

RESULT ANALYSIS

4.1   TESTS PROCEDURES

4.2 PROCEDURE FOR HEATING TEST

4.3 PROCEDURE FOR COOLING TEST

4.4 RESULTS

4.5 CARE AND MAINTAIN OF THE PROJECT

CHAPTER FIVE

• CONCLUSIONS

5.3     REFERENCES

CHAPTER ONE

1.0                                                               INTRODUCTION

A solar cooker is a device which uses the energy of direct sunlight to heat, cook or pasteurize drink. Many solar cookers currently in use are relatively inexpensive, low-tech devices, although some are as powerful or as expensive as traditional stoves, and advanced, large-scale solar cookers can cook for hundreds of people. Because they use no fuel and cost nothing to operate, many nonprofit organizations are promoting their use worldwide in order to help reduce fuel costs (especially where monetary reciprocity is low) and air pollution, and to slow down the deforestation and desertification caused by gathering firewood for cooking. Solar cooking is a form of outdoor cooking and is often used in situations where minimal fuel consumption is important, or the danger of accidental fires is high, and the health and environmental consequences of alternatives are severe. Many types of solar cookers exist, including parabolic solar cookers, solar ovens, and panel cookers, among others. But in this work, we are focusing on parabolic type of solar panel.

1.1                                         BACKGROUND OF THE PROJECT

A parabolic solar cooker is essentially a solar thermal collector used to cook food or pasteurize water. Parabolic designs have been used for centuries. The idea to concentrate light using curved mirrors was developed by the Greeks, Aztecs, Incas, Romans and Chinese. The Incas used bronze and gold for their mirrors and they built structures that were several stories high. This technology seems to have appeared around the same time for each of the civilizations.

There are many designs and models for parabolic solar cookers. Some are made with locally gathered scrap materials while others are manufactured using highly machined, durable but more expensive materials.

A parabolic cooker concentrates sunlight. Ordinary sunlight is already dangerous (if the sun is viewed directly without protection) so concentrated sunlight can be much more so. The larger the parabola, the greater the danger. Ways of reducing the danger include:

1. Safety rules.
2. Note that these mostly reduce the danger rather than eliminate it:

1. Putting the focal point inside the parabola (deep dish focus), so someone would have to put their head inside to expose themselves to danger. (There is still a danger if someone unwisely checks a problem or tries to do maintenance while the parabola is pointed towards the sun, or if children are playing.)
2. Using a physical barrier to prevent people going near the danger point.
3. A table to protect the cook from burns and dazzles.
4. Keeping the parabola small.
5. Designing the parabola to avoid a small sharp focal point. This requires that the cooking vessel have a relatively large surface area to catch the reflected rays. This would make it more likely for someone to be struck by the focused rays, but less damaging if it actually happened.
6. Maximizing the efficiency of absorption by the cooking vessel.

The risk can be reduced but not eliminated. Other solar cooker designs have much less risk, and are probably a better option in situations where they can provide enough heat. Alternatively, integrated cooking and improved cookstoves with fuels from waste biomass may be safer options which use only modest amounts of resources.

1.2                                               PROBLEM STATEMENT

People are moving away from other fuel sources such as wood, coal, or natural gas because of their harmful by-products and unavailability. Solar cookers also remove a large burden on many poverty stricken areas by giving them a constant means of water purification, so long as the sun is up. Every day people find new ways to harness sunlight as a clean, renewable, and powerful source of energy.

This particular parabolic solar cooker is also useful because it has an expansion pipe which allows the angle of the reflective dish to be adjusted while cooking. It is also large enough to capture and concentrate enough sunlight to boil water in 10 minutes.

1.3                                             OBJECTIVE OF THE PROJECT

The objective of this work is to design Parabolic solar cooker which uses a parabolic-shaped reflector to direct sunlight to a small area in order to generate heat for cooking. This device/or appliance is able to reach high temperatures, 350 °C (662 °F), which allows them to be used for grilling and frying.

1.4                                                       SCOPE OF THE PROJECT

This device/or appliance is able to reach high temperatures, 350 °C (662 °F), which allows them to be used for grilling and frying. These temperature is significantly higher than what can be reached by a solar box cookers or solar panel cookers and allow the cooking times on a parabolic cooker to be comparable to a conventional stove, such as an electrical or gas burner.

The amount of food being cooked and the way in which the heat is used is generally dictated by the size of parabolic dish. Smaller dishes, which are generally around one meter in diameter, are intended to heat a traditional size pot or pan much like how you would cook on a traditional cooktop. The larger dishes, which can be as wide as five meters in diameter, are generally not used to heat a pot or pan directly, but instead are used to create steam by directing sunlight onto pipes carrying water. The steam is directed to cooking surfaces in a kitchen and is regulated by valves in order to offer control to the chef.

1.5                                         SIGNIFICANCE OF THE PROJECT

We use “Parabolic Solar Cooker” almost every day to fry, boil, steam and brown and re-heat many of our daily meals.

Parabolic solar cooking recipes do call for browning of meats, gravies, vegetables and such so, we will often use our parabolic to accomplish this when we are in a bit of a hurry; otherwise we will also use the solar ovens and panel cookers to do the same for many of these aforementioned foods.

Frying is very easily accomplished using the “Parabolic Solar Cooker” because of the very high temperatures. We always use a deep pan with a lid to help minimize the splattering of oil onto the parabolic, and the same goes for when boiling potatoes, pastas and such.

1.6                                                    PURPOSE OF THE PROJECT

The purpose of a solar cooker is to convert sunlight into heat energy to cook food. There are three main types of solar cookers: box, panel, and parabolic. Box cookers act more as an oven and store a large amount of heat while panels and parabolas reflect light directly onto the cooking surface. A parabolic reflector is one of the most efficient ways to harness sunlight; its unique shape concentrates all of the sunlight at one focal point. The main purposes of this study are:

1. To critically evaluate the solar cooker situation and possibilities in Nigeria.
2. To design the best suitable parabolic solar cooker.

1.7                                          APPLICATION OF THE PROJECT

1. A. In the summer time, parabolic solar cooker is used to cook breakfast items such as oatmeal, cracked wheat, eggs, sausage etc. This can be accomplished as early as 8:30 AM at the highpoint of the summer because the sun rises so early, but come wintertimethe earliest you could do so would be, probably 10:30-11:00 AM at the earliest, due to the shorter days with the sun so low on the southern horizon.
2. Water can be boiled very rapidly on the parabolic solar cooker,in fact just as quickly as, and even more so, than on many electric range stove tops. We will use the parabolic to heat water for many uses during the day, besides just for cooking. We also love to pop up popcornin a pot using popcorn oil or olive oil.

With parabolic solar cooker users can be able to cook anything we desire whenever the sun is shining.

1.8                                          ADVANTAGES OF THE PROJECT

• High-performance parabolic solar cookers can attain temperatures above 290 °C (550 °F). They can be used to grill meats, stir-fry vegetables, make soup, bake bread, and boil water in minutes.
• Solar cookers use no fuel. This saves cost as well as reducing environmental damage caused by fuel use. Since 2.5 billion people cook on open fires using biomass fuels, solar cookers could have large economic and environmental benefits by reducing deforestation.
• When solar cookers are used outside, they do not contribute inside heat, potentially saving fuel costs for cooling as well. Any type of cooking may evaporate grease, oil, and other material into the air; hence there may be fewer cleanups.

1.9                                      DISADVANTAGES OF THE PROJECT

• Parabolic Solar cookers are less useful in cloudy weather and near the poles (where the sun is low in the sky or below the horizon), so an alternative cooking source is still required in these conditions.
• Parabolic solar cooker takes longer to cook food than a conventional stove or oven. Using solar cookers may require food preparation start hours before the meal. However, it requires less hands-on time during the cooking, so this is often considered a reasonable trade-off.
• Cooks may need to learn special cooking techniques to fry common foods, such as fried eggs or flatbreads like chapatis and tortillas. It may not be possible to safely or completely cook some thick foods, such as large roasts, loaves of bread, or pots of soup, particularly in small panel cookers; the cook may need to divide these into smaller portions before cooking.
• Parabolic solar cooker designs are affected by strong winds, which can slow the cooking process, cool the food due to convective losses, and disturb the reflector. It may be necessary to anchor the reflector, such as with string and weighted objects like bricks.

1.10                                         LIMITATION OF THE PROJECT

• Requires periodic adjustment to refocus it as the sun moves or a mechanical solar tracking
• Generally more expensive than panel and box cookers.

1.11                                             PROJECT ORGANISATION

The article is divided into five sections including this introduction. Section 2 is on the trend and causes of oil spillage in Nigeria whereas the study area and method of data collection are in Section 3. Results of findings are discussed in Section 4. The way forward is and conclusion in Section 5.