eChapters

3.1 Introduction

The sun emits electromagnetic radiation, which is referred to as solar radiation. Every location on the Earth’s surface receives some sunlight during the course of the year, but the amount of solar radiation varies. On a daily basis, we see much less energy from the sun than it emits and incident upon the earth. In an hour and a half, the amount of sunlight that reaches the surface of the earth is enough to provide enough energy for an entire year. 

7.1 Introduction

A greenhouse is quasi-permanent structure, covered with a transparent or translucent material, ranging from simple homemade designs to sophisticated pre-g\fabricated structures, wherein the environment could be modified suitable for propagation or growing of plants. Materials used to construct a greenhouse frame may be wood, bamboo and steel or even aluminum. Covering can be glass or various rigid or flexible plastic materials. Depending on the covering material, different terminology have been used in the context of greenhouse structures as mentioned below:

Glasshouse: A greenhouse with glass as the covering material is called glasshouse

Polyhouse: It is a greenhouse with polyethylene as the covering material.

Solar heat plays a pivotal role in the functioning of greenhouses, serving as a primary energy source that influences the internal climate crucial for plant growth. The absorption of solar radiation by the greenhouse covering material initiates a complex process of heat transfer, involving conduction, convection, and radiation. This solar energy, once absorbed, contributes to elevating the temperature within the greenhouse, creating a favorable environment for plants. A fundamental understanding of solar heat dynamics is essential for optimizing greenhouse design and operational efficiency.

9.1 Introduction

Basically, for heating or cooling the space using solar energy, the solar energy is to be collected, stored and distributed properly in the space to be heated or removed from the space to be cooled. There are two basic approaches for solar houses, there are:

(a)Active solar house technology

(b)Passive solar house technology

In active approach, the solar energy is collected and stored in some separate solar energy collector and then energy is distributed in the space where heating is to be done using electrically operated pumps and fans coupled with radiator etc. The storage of solar energy in active solar house may be in the form of storage as sensible heat or storage as latent heat or chemical heat storage. As per requirement of heating the size of solar collector and storage system be decided. Generally, the active concepts of solar houses are used for heating purpose. Active concept can also be used for space cooling applications. Solar vapor compression and absorption system can be used for this purpose, essentially, this includes incorporation of solar heat collectors, thermal storage system, auxiliary heat supply system (to compensate intermittent nature of sun energy) and control systems. Further, there are three ways of solar space heating i.e. solar air systems, solar liquid systems and solar heat pump systems.

Introduction

In Indian Thar desert regions, excessive heat is the major problem that causes human and animal thermal discomfort. Space cooling is, therefore, the most desirable factor for the inhabitants. Various examples of dwellings responsive to climatic constraints are found in vernacular architecture throughout the world. Compact cellular layout with minimum external surface exposure to the sun, whitewashed surfaces to reduce absorptivity, blind external facades, courtyards, vegetation to provide humidity and shade, and heavy buildings constructed from high thermal capacity materials are common passive features in most of the arid regions. Wind towers for cooling ventilation are well known in Iranian and Middle East architecture, which along with cooling of the air by earth and water evaporation keep the building comfortable in hot periods. Building underground to take advantage of the large thermal storage capacity of the earth is also used in Tunisia and central Turkey.

9.1 Introduction

Solar energy can be directly converted into electrical energy through photovoltaic route. Energy conversion devices which are used to convert sun light into electricity by use of the photovoltaic effect are called solar cells. The advantages of solar cells are:

1. They are reliable, convenient and durable.
2. It is green, sustainable and pollution free technology.
3. Directly solar radiation can be converted into electricity (conversion of global solar light by flat plate photovoltaic).
4. Maintenance cost is quite low therefore suitable even in isolated and remote area, since no moving parts are involved.
5. Solar cells are quite compatible with almost all environments, respond instantaneously with solar radiation.
6. Considerable expected lifetime i.e. 20 years or even more.
7. No distribution system is required, because they are decentralized source of energy and located at the place of use.

8.1 Introduction

Solar energy can be directly converted into electrical energy. Energy conversion devices which are used to convert sun light into electricity by use of the photovoltaic effect are called solar cells. The advantages of solar cells are:

1.They are reliable, convenient and durable.

2.It is green, sustainable and pollution free technology.

3.Directly solar radiation can be converted into electricity (conversion of global solar light by flat plate photovoltaic).

4.Maintenance cost is quite low therefore suitable even in isolated and remote area, since no moving parts are involved.

5.Solar cells are quite compatible with almost all environments, respond instantaneously with solar radiation.

6.Considerable expected lifetime i.e. 20 years or even more.

Introduction

Agriculture has been the back bone of Indian economy and culture and it will be continued to remain as such for a long time in future. Parallel to this, energy security of a country is also very important and efforts have been given on renewable energy utilization since the fossil fuel based energy is depleting at a very fast rate. In agricultural fields, considerable amount of energy is used to do different field activities e.g. ploughing, irrigation through pumps, intercultural operations, spraying of agricultural chemicals for plant protection, harvesting, post-harvest processing etc. Therefore, there is also need to replace the conventional energy source with renewable sources to operate above mentioned agricultural activities.

Approximately, 35% of the crop production is damaged if pest and diseases are not controlled at right time. Uniform spraying of liquid formulations throughout the crop field is very important for effective control of pest and diseases. Using sprayer, liquid pesticide formulations are generally broken down to minute droplets of effective size for uniform distribution over a large surface area. Different types of sprayers are used in agricultural field based on different requirements.

Introduction

Water is the primary source of life for mankind and one of the most basic necessities for crop production. The demand for water to irrigate the crops is increasing. For sustainable production from agricultural farms, irrigating the crops at right stages is highly important. Even in rainfed situation, lifesaving irrigation during long dry spell has also been found beneficial for crop survival and to obtain the targeted yield. Considering the depletion of groundwater below the critical zone in most part of the country, energy intensive pumping for irrigation is not a viable option. Therefore utilization of available runoff water through surface storage systems followed by pumping may be a potential solution to achieve the set goal of ‘crop per drop’ mission. In this connection, micro-irrigation system including drippers and sprinklers is of great importance. However, ensured power supply is essential to operate the micro-irrigation system even in remote areas. Reliable solar photovoltaic (PV) pumps are now emerging in the market and are rapidly becoming more attractive than the traditional power sources. These technologies, powered by renewable energy sources, are especially useful in remote locations where a steady fuel supply or electricity supply is problematic. About 16 million electric pumps and 7 million diesel pumps are in operations in the country for irrigation purpose; however they are highly energy intensive. Moreover, diesel operated and electrified pumps directly or indirectly emit large amount of CO₂ gas in atmosphere and hence are not environment friendly. To meet the energy demand for irrigation, solar PV pumps have been introduced under the off-grid power generation category of National Solar Mission (NSM) with a target of 1000 MW by the end of phase II (2013-2017). The target has been revised in 2015 to a total grid connected solar power generation of 1,00,000 MW comprising 40,000 MW roof top generation and 60,000 MW grid connected solar power plants (Resolution of MNRE, Govt of India, No. 30/80/2014-15/ NSM dated 1^st July 2015).

Sun is the prime source of energy injected into the earth’s atmosphere. The sun is the nearest star to the earth. It is a hot ball of glowing gases at the heart of the solar system. Its radiant energy is practically the only energy source to the earth. Very small and insignificant quantities of energy are available from other sources such as the interior of the earth, the moon, and other stars. Without the sun’s intense energy and heat, there would be no life on earth.

The mean distance of the sun from the earth, also known as one astronomical unit (1 AU), is approximately 1.496 × 10⁸ km, though the distance varies as the earth revolves round the sun in an elliptical orbit. At this average distance, light travels from the sun to earth in about 8 minutes and 19 seconds. The energy of the sunlight supports almost all life on earth by photosynthesis, and drives earth’s climate and weather. The minimum sun-earth distance is about 0.983 AU and the maximum is approximately 1.017 AU. The earth is at its closest point to the sun (perihelion) on around January 3 and at its farthest point (aphelion) on around July 4.

The sun makes up about 99.86% of the mass of the entire solar system. The visible disk or photosphere has a radius of 6.599 × 10⁵ km, and the solar mass is 1.989 × 10³⁰ kg. The sun is a completely gaseous body. The chemical composition (by mass) of the outer layers of sun is 71 per cent hydrogen, 26.5 per cent helium, and 2.5 per cent heavier elements like oxygen, carbon, neon, and iron among others. Since the sun is not a solid body, different parts of the sun rotate at different rates. At the equator, the sun spins once about every 25 earth days, but at its poles the sun rotates once on its axis every 36 days.

3.1 The Sun

The Sun is a star. It is a huge, spinning, glowing sphere of hot gas. It appears so much larger and brighter than the other stars because we are so close to it. The Sun is the center of our Solar System and contains most of the mass in the Solar System. All of the planets in our Solar System, including Earth, orbit around the Sun. In sun the energy generation is a multi-step process of thermo-nuclear fusion reactions. In the thermo nuclear fusion hydrogen (four protons) combines to form helium (one helium nucleus). The mass of the helium nucleus is less than that of four hydrogen protons and mass having been lost in the reaction is converted to energy. The reaction is represented as

5.1 Introduction

Energy in the form of heat is one of the main energy requirements in domestic, agricultural, industrial and commercial sector of our economy. From an enduse point of view, solar thermal energy finds its application in these areas. Solar thermal energy devices convert radiant energy of the sun into thermal energy for different productive works. In fact, solar energy consists of infrared radiation, it is characteristics of infrared radiation that whenever it falls on any object, it converts into thermal heat energy.

The conversion of sun light into thermal energy is easily or conveniently achieved by means of a metallic or plastic cover, painted black with ordinary black board paint or having selected coating over it and covered with one- or double-glazing cover for transmitting solar radiation inside it. This metallic cover is known as absorber, below it either channels or pipes or passages for allowing entry of water or air are provided, through which heat energy is transferred to working medium either air or water. The absorber plate is covered with suitable thickness of insulating material on its back or sides for preventing loss of heat from the absorber plate. This complete system is enclosed in an airtight box. When exposed to solar radiations, the blackened metallic surface absorbs solar energy and converts into heat. This heat could be used for cooking of food, heating of water and air, evaporation of moisture form the grains etc. In fact, absorber works on the principle of black body, which absorbs maximum and a good absorber, is a good emitter. Hence generated heat could be utilized for different applications.

Greenhouse essentially functions based on solar energy to control environment for protecting cultivation from adverse condition. Computer simulation and mathematical modeling are important tools for determining the energy efficient design as well as predicting the overall system performance. The greenhouse climate may be used for crop drying, distillation, biogas plant heating, space conditioning, and aquaculture. Thus, any required configuration of greenhouse can be thermally modeled for predicting and optimizing the performance. The solar energy based greenhouse modeling are useful in evaluation of various applications like greenhouse heating, greenhouse cooling, greenhouse drying and aquaculture greenhouse. Greenhouse clubbed with ground air collector increase in plant and ambient temperature of 5–7°C during night in winter. Whereas, using evaporative cooling pad with greenhouse reduces the ambient temperature of 4–5°C during midday summer. A greenhouse can be very well used for large-scale crop drying, while not in use for cultivation. Some other applications such as covered crop drying and aquaculture are also discussed.

Introduction 
In a time when the world is in dire need of sustainable energy solutions, investigating biofuels becomes an essential path to supplying the always expanding supply[1]. This book chapter explores the dynamic world of solid and liquid biofuels, providing a thorough analysis of their properties, methods of production, uses, and wider ramifications in relation to renewable energy sources. Setting the scene, the introduction clarifies the role of biofuels in the larger context of renewable energy. Exploring solid and liquid biofuels becomes critical as the globe struggles with issues like climate change, depleting fossil fuel reserves, and the need to switch to cleaner energy sources[2]. These biofuels, which are defined as energy carriers made from biomass, offer a viable substitute and have the capacity to both reduce environmental impact and promote energy security. As the chapter progresses, biofuels are divided into two main categories: liquid and solid. Biofuels that are solid, such as wood, agricultural leftovers, pellets, and briquettes, serve as a starting point for investigating alternative energy sources. This section walks readers through the complexities involved in producing solid biofuel, including harvesting, pre-treatment, and creative pelletization methods. By doing this, it highlights the renewable nature of solid biofuels and their ability to lower greenhouse gas emissions, highlighting their benefits for the environment. Simultaneously, difficulties associated with its application, ranging from administrative worries to land use issues, are examined closely. Turning its attention to liquid biofuels, the chapter tells the story of ethanol, biodiesel, and advanced biofuels. By examining the choice of feedstock, manufacturing procedures, and real-world uses, it highlights the adaptability of liquid biofuels in the energy system. Although they are not without difficulties related to land use, food production, and water use, their ability to function with current infrastructure and their critical role in improving energy security stand out as distinguishing characteristics[3].

Urbanization, industrialization, and economic growth in India have all led to an increase in the generation of municipal solid waste (MSW) by a number of urban local bodies (ULBs). In cities with high population densities, SWM is a significant difficulty. Being a diverse country with a wide range of religious communities, customs, and traditions like India makes it more challenging to accomplish sustainable development in a country that is rapidly industrialising and improving its standard of living. Although there have been substantial changes in the social, economic, and environmental spheres, India’s SWM systems have mostly remained the same. Currently, 90% of residual waste is thrown in the informal sector rather than properly disposed of. To make SWM more sustainable, new management practises and disposal sites are needed. The inefficiency of the current waste management systems has a detrimental effect on the economy, the environment, and public health. The Ministry of Environment and Forests of India introduced regulations for garbage treatment, although there is irregular and insufficient compliance.

Percent Solutions

There are three types of percent solutions. All are parts of solute per 100 total parts of solution. Based on the following definitions you may calculate the concentration of a solution or calculate how to make up a specific concentration

    1.    % W/W - Percent of weight of solute in the total weight of the solution. Percent here is the number of grams of solute in 100 grams of solution. 
        Example: 
        A 100% (W/W) NaCl solution is made by weighing 100 g NaCl and dissolving in 100 g of solution

    2.    % W/V - Percent of weight of solution in the total volume of solution. Percent here is the number of grams of solute in 100 ml of solution. This is probably the least significant way of naming a solution, but the most common way of doing it. In fact, any percent solution not stipulated as W/W, W/V, or V/V is assumed to be % W/V. 
        Example : A 4% (W/V) NaCl solution is 4 g of NaCl in 100 ml of solution.

    3.    % V/V - Percent of volume of solute in the total volume of solution %V/V. Percent here is the number of milliliters of solute in 100 ml of solution. 
        Example: A 10% (V/V) ethanol solution is 10 ml of ethanol in 100 ml of solution; unless otherwise stated, water is the solvent. 

Introduction to Energy Sources

Consumption of nonrenewable energy sources has caused more environmental harm than any other human activity during the last century. Electricity generated from fossil fuels like coal and crude oil has resulted in excessive levels of hazardous gases in the environment. As a result, several issues exist now, such as ozone depletion and global warming. Vehicle pollution has also been a significant issue.

As a result, alternative energy sources have become increasingly vital and relevant in today’s society. These sources, such as the sun and wind, can never be depleted and are hence referred to as renewable. They produce fewer emissions and are readily available locally. Their application has the potential to significantly reduce chemical, radioactive, and thermal pollution. They stand out as a promising source of infinite clean energy. These are also known as non-conventional energy sources.

2.1 Introduction

Rain and snow are the two chief sources of water of the earth. In-situ conservation of rainwater helps the plants to meet some of their consumptive uses directly. Not all the amount of rainwater that falls at a point is conserved by the soil reservoir to support the plant growth. Some part of it flows over the soil surface as surface runoff and some seeps down as infiltration and finally adds to the underground reservoir. Therefore, rain or snow, which is not used directly by the plants, becomes a potential source of either surface or ground water for irrigation. In areas with extreme low temperature, snow contributes major source of water supply wherever, in humid and sub humid regions, rain is the principal source. Precipitation, rain or snow, is the first stage of the continual cycle of water in its round from atmosphere to the earth and return by evaporation from water bodies, snow surfaces and land surfaces. The continual cycle of distribution of water is governed by the process called as hydrologic cycle. Thus, precipitation or atmospheric water is the first form of water above the earth’s surface, the second form being the surface water on earth and the third form is the subsurface water or underground water. The study of occurrence, distribution and circulation of precipitation through the unending hydrologic cycle forms the basic part of study of hydrology. As mentioned above, the part of precipitation that is not used by the plants in-situ flows over the soil surface as runoff and contributes to either surface or ground water supply.

Engineering hydrology is the science that deals with the estimation of runoff and its transmission from one place to the other, besides dealing with the properties of water in nature. For, an engineer, surface and groundwater are the two most important components to deal with. But due to lack of data of stream flow, it is usually necessary to study precipitation, evaporation and percolation to indirectly determine the availability of surface and groundwater. For planning and management of water resources systems, an engineer has to estimate (i) water resources potential of a basin, (ii) dependable yield for irrigation and hydel power generation and industrial water demand (iii) probability of occurrence of floods with their magnitude, (iv) sediment yield and transportation (v) hydrometeorology (vi) new sources of water for irrigation (vii) stream flow forecasting by use of precipitation data (viii) water control, navigation, control of soil erosion and control of pollution of water bodies and (ix) operation and maintenance of river valley projects. For estimation of the above mentioned parameters, it is important to understand the hydrologic cycle properly.

2.1 Introduction

Rain and snow are the two chief sources of water of the earth. In-situ conservation of rainwater helps the plants to meet some of their consumptive uses directly. Not all the amount of rainwater that falls at a point is conserved by the soil reservoir to support the plant growth. Some part of it flows over the soil surface as surface runoff and some seeps down as infiltration and finally adds to the under ground reservoir. Therefore, rain or snow, which is not used directly by the plants, becomes a potential source of either surface or ground water for irrigation. In areas with extreme low temperature, snow contributes major source of water supply wherever, in humid and sub humid regions, rain is the principal source. Precipitation, rain or snow, is the first stage of the continual cycle of water in its round from atmosphere to the earth and return by evaporation from water bodies, snow surfaces and land surfaces. The continual cycle of distribution of water is governed by the process called as hydrologic cycle. Thus, precipitation or atmospheric water is the first form of water above the earth’s surface, the second form being the surface water on earth and the third form is the subsurface water or underground water. The study of occurrence, distribution and circulation of precipitation through the unending hydrologic cycle forms the basic part of study of hydrology. As mentioned above, the part of precipitation that is not used by the plants in-situ flows over the soil surface as runoff and contributes to either surface or ground water supply.

18.1. What?

The basic objective of sowing is to place the seed in rows at the desired depth, to maintain proper spacing between seed to seed, cover the seeds with soil and provide proper compaction over the seed if required. Precise sowing/planting helps in better crop stand. This helps to achieve optimum yields. Traditional sowing methods include broadcasting manually, opening furrows by a country plough and dropping seeds by hand (i.e.) dibbling. In the present day, improved seed-cum-fertilizer drills are used for sowing and fertilizer application. These are provided with seed and fertilizer boxes, metering mechanism, furrow openers, covering devices, frame, ground drive system and controls for variation of seed and fertilizer rates.

18.2. Types of sowing/planting equipment

Sowing equipment include seeders and transplanters. Various types of sowing equipment, viz., manually operated, animal drawn, power operated and tractor drawn are used throughout India.

18.2.1. Seed drills

Seeders are available for sowing seeds of various crops. Some seeders have been designed with adjustable metering mechanism which makes them versatile for sowing two or three kinds of seeds. For example, a multicrop planter developed by CIAE is used for sowing garlic, maize, moong, peas and groundnut. Similarly, the institute has developed a small seed sowing drill which is used for sowing small seeds such as bajra, rapeseed and mustard.