CHAPTER ONE
INTRODUCTION
Background of Study
The art of cooking, baking, heating and drying remain fundamental skills and are important for nutrition, as cooked and baked goods, especially breads, are common both from an economic and cultural point of view. These cooking methods can be best achieved using oven. An oven is an insulated chamber or compartment used for baking, roasting, drying and heating of substance [1]. Electric ovens generally get a thumbs-up all around when it comes to baking. It is the best and cleanest advancement in food preparation such that it does not totally requires human to monitor while in operation. When once the temperature and time required for cooking a particular substance is set, the system can complete the remaining activities. It involves the use of thermostat, heating elements, casing, conductors, outlet plug, blower, selector switch and LED indicator in its construction. It applies the concept and principle of energy conversion; electrical energy to thermal energy both as convection and conventional heating.
Electric ovens have electric coils (heating elements) at the floor and at the roof of the oven compartment. This coil pushes radiant heat upward and downward into the oven compartment at a fairly steady and even rate. The coil at the roof serve as a broiler which can be used for cooking at a high temperature while the one at the floor of the oven keeps the oven compartment hot at a steady temperature for baking and other purposes. Electric ovens are generally awesome for baking. During baking, heat is gradually transferred to the center of the baked item, resulting in baked goods having a firm dry crust and a softer center [2]. The coils heat and cool slowly, which may sound negative but actually results in steadier heat with fewer spikes and drops of temperature. The heat is also less intense when the coils are fully on, so there should not be same incidence of undersides burning as it is with gas ovens. Additionally, the oven environment is drier, which helps foods crisp up and turn golden-brown [3].
As of 2005, Nigeria has the highest rate of deforestation in the world according to the Food and Agriculture Organization of the United Nations (FAO) [4]. Between 2000 and 2005 the country lost 55.7% of its primary forests, and the rate of forest change increased by 31.2% to 3.12% per annum. Forest has been cleared for logging, timber export, subsistence agriculture and notably the collection of wood for fuel which remains problematic in western Africa.
Deforestation is a process where vegetation is cut down without any simultaneous replanting for economic or social reasons. Deforestation has negative implications on the environment in terms of soil erosion, loss of biodiversity ecosystems, loss of wildlife and increased desertification among many other reasons [5]. Deforestation also has impacts on social aspects of the country, specifically regarding economic issues, agriculture, conflict and most importantly, quality of life. According to data taken over 2000 to 2005 Nigeria, located in the western region of Africa, has the largest deforestation rates in the world, having lost 55.7% of their primary forests [5]. Forest is defined as thick vegetations with no visible signs of past or present human activities [5].
The annual rate of deforestation in Nigeria is 3.5%, approximately 350,000 to 400,000 hectares per year [5]. The Food and Agriculture Organization of the United Nations lists the requirements of sustainable forest management as: extent of forest resources, biological diversity, forest health and vitality, productive functions of forest resources, protective functions of forest resources, socio-economic functions and a legal, policy and institutional framework [6]. Many aspects of the outline are currently not being met and will continue to have detrimental effects if not quickly addressed.
A lot of damage has been done to Nigeria’s land through the processes of deforestation, notably contributing to the overwhelming trend of desertification. Desertification is the encroachment of the desert on land what was once fertile. A study conducted from 1901 to 2005 gathered that there was a temperature increase in Nigeria of 1.1 °C, while the global mean temperature increase was only 0.74 °C. The same study also found in the same period of time that the amount of rainfall in the country decreased by 81mm [6].
Hence, this project design will help in minimizing deforestation in the country especially in the urban areas as there is consistent power supply and recent inventions of other sources of electricity. Also, this project design brings an insight in the working principle, the electrical installation, the science of measurement and control and intellectual building ability in interpretation of working drawings in designing and development before, during and after working process.
Statement of the Problem
The lack of fuel (petroleum products scarcity) is one of the major challenges faced by many of us in the country which at times lead to a mass protest against the government for inability to cater for the people’s needs in general. In addition to that, many of us who reside in big cities who use firewood for cooking or baking will agree with us that it is not often easy to get firewood from the forest since deforestation is another challenge face in most parts of the country. Above all, fuel consuming cookers and ovens have two outstanding deficiencies, which are; sooty preheating and problem of dogged nozzles which lead to offensive, discouraging and dirty burning. Firewood in the other hand has an inconvenience smoke which in addition affects the taste of food cooked and also has a dirty burning. Therefore, this design strives for a source of energy that is comparatively cheap, clean, safe and available. It also aims at making domestic cookers and ovens safe enough as against highly flammable liquid or gas fuel. In a close observation, large scale cooking and drying of meat, fish sellers, commercial corn roasters, food sellers and “suya” sellers, etc, need efficient heating system. For this reason electric oven has come into function in order to suppress these problems.
Aim and Objectives of the Project
The aim of this project is to design and construct an electric oven that would conserve the thermal energy generated within the oven. Also, it aims to incorporate both convectional and conventional electric ovens. Other specific objectives are
To compare the different types of oven available in the market.
To select the best components for the construction of this oven.
To exploit local materials for the production of electric oven as against imported oven.
To incorporate both convection and conventional types of electric oven.
To design and fabricate the necessary parts of an electric oven.
To assemble the different parts so as to achieve the aim of the project.
To perform finishing work on the assembled parts
1.4 Expected Benefits of the Project
It serves as guide and manual for the construction, installation, maintenance and repair of different possible faults in electric ovens.
ii. It will serves as a medium of knowing the principle of operating the model work, which will definitely be of great benefit to the department and the society.
iii. It serves as an alternative means for baking instead of using the gas oven and the firewood
iv. Convenience in baking devoid of the fear of fire outbreak.
vi. Control of global warming as deforestation is reduced.
vii. To be able to meet National university commission (NUC) requirement in awarding Bachelor of Engineering, BENG in Electrical and Electronic Engineering.
Scope of Study (limitation and delimitation)
The scope of this project is to design and construct an electric oven that would utilize effectively the thermal energy generated in the oven through the use of local insulated materials. The insulation would be able to solve the problem of failure of internal components as seen in some ovens due to overheating. The combination of both convection and conventional ovens is of added advantage, as temperature variation within the oven is adequately managed. Also, the project works with resistance of the heating element having a minimum and maximum voltage range from 220-240 V. The limitations of this work include;
Single production is relatively expensive compared to mass production.
Precautions must be strictly adhered to avoid fire outbreak and burns.
There may be slight temperature variation within the different chambers of the oven.
It requires regular and proper maintenance as moisture and oil accumulation may result into rusting.
It can only be used where there is electricity
Structure of the Report
This project work report is divided into five chapters. Chapter one is the preliminary chapter disclosing the project objectives, benefits, scope and problem statement of the project. Chapter two of this project work seeks to review past work of researchers and their methods of design. Chapter three accords the design methodology and components description of the project. Chapter four focuses on the construction procedure and testing. Chapter five summarizes, concludes and recommends for further research on this project.
DESIGN AND CONSTRUCTION OF AN ENERGY EFFICIENT ELECTRIC OVEN
