The 'fuel crises' in 1972-73 generated world wide effort for the search for an Alternative Energy source to fossil fuels. Solar energy was identJfied as one of the alternatives to fossil fuels. On one hand the developed countries are trying to maintain their standard of living while the developing countries are trying to solve their industrial, social and economical problems to increase their standard of living. After this period a lot of Research and Development in the field of solar energy was carried out both in developing and developed countries and solar energy is utilized in domestic, agricultural and industrial sectors and also in the space. During the period of ,"Oil Crises" industrialized countries expended their activities in solar energy and substantial progress was made. In few developing countries seperate funding in the field of solar energy R&D was also provided through national and international, organizations. Time has now come when one should seriously look into the problems and screen, select, adapt, and manage emerging solar energy technology for its use in developing countries. Also the International Organizations will have to play a major role in this direction which may assist building up of a local solar energy R&D and manufacturing capabilities in developing countries which should be based on a long term but on necessary basis.

The 'fuel crises' in 1972-73 generated world wide effort f6r the search for an Alternative Energy source to fossil fuels. Solar energy waS identified as one of the alternatives to fossil fuels. On one hand the developed countries are trying to maintain their standard of living while the developing countries are trying to solve their industrial, social and economical problems to increase their standard of living. After this period a lot of Research and Development in the field of solar energ'y was carried out both in developing and developed countries and solar energy i. utilized in domestic, agricultural and indvstrial sectors and also in the space. During the period of "Oil Crises" industrialized countries expended their activities in solar energy and substantial progress was made. In f. ew developing countries seperate funding in the field of solar energy R&D was also provided through national and international, organizations. Time has now come when one should . eriously look into the problems and screen, select, adapt, and manage emerging solar energy technology for its use in developing countries. Also the International Organizations will have to play a major role in this direction which may assist building up of a local Solar energy' R&D and manufacturing capabilities in developing countries which should be based ori a long term but on necessary basis.

H.P. Garg Centre of Energy Studies Indian Institute of Technology Hauz Khas, New Delhi 110 016 India Heating of water using solar energy is not new and by using a little science and technology in it, the solar energy can be utilized more effectively and economically for heating the water both for domestic and industrial applications. Solar Water Heaters are popular for the last three decades in countries like USA, Australia, Israel, Japan, India. This is the only solar energy application which is commercially, technic ally and economically viable and has been studied for more than 30 years in many countries. Technical advances in solar water heating have been very rapid in the last 30 years. These are becoming popular not only for domestic use but for large establishments like hostels, hotels, hospitals, industries such as Textile, Paper and Food Processing and even in heating of swimming pools in winter. In few instances the cost of solar water heating systems may be higher than those operated by electricity, gas or other fuel but over a period of time this is more than recovered by the savings in the cost of operations and maintenance.

This volume is the third in the series of the book entitled, 'Advances in Solar Energy Technology'. The purpose of writting this multiple volume book is to provide all the relevant latest information in the field of Solar Energy (Applied as well as theoretical) to serve as the best source material at one place. Attempts are made to discuss topics in depth to assist both the students (undergraduate, pos- graduate, Research Scholars) and the professionals (consulting, design, contracting firms). The third volume discusses the heating, agricultural and photovo1taic applications of Solar Energy. Chapter 1 deals with solar cookers, one of the important application area for developing countries. After discussing the history of solar cookers, eight types of direct solar cookers, two types of box solar cookers and two types of advanced solar cookers are discussed in detail. The performance studies carri d out on direct type and on box type solar cookers are also presented. A test procedure for rating a box type solar cooker is also introduced. The limitations and advantages of various cookers are discussed briefly in the chapter. Desalinated water for drinking purposes, for industrial and agricultural applications is required. The topic of Solar Distillation is discussed in detail in chapter two. Solar Distillation has a long history and in this chapter various kind of solar stills like conventional solar still, tilted tray solar still, wick type solar still, mUltiple effect diffusion solar still, multistage flash distillation, etc.

The purpose of writing this three volume 'Advances in Solar Energy Technology' is to provide all the relevant latest information available in the field of Solar Energy (Applied as well as Theoretical) to serve as the best source material at one place. Attempts are made to discuss topics in depth to assist both the students (i.e. undergraduate, postgraduate, research scholars etc.) and the professionals (i.e. Consultancy, design, and contracting firms). Chapter 1 starts with a brief history of solar houses (active heating), one of the oldest and still the widely used application of Solar Energy. Various methods of build ing heating and other general aspects such as building form and functions are also described. Various components of active solar heating of building like solar collector, storage system, control unit, auxiliary heat source, etc. are discussed very briefly. Three types of solar active heating of buildings like Solar air systems, solar liquid systems, and solar assisted heat pump systems are discussed in detail in this chapter. Design details and performance of nine typical solar houses which are in use in different climatic conditions and using some newer concepts are also discussed in depth in this chapter."

The main objective of writing the three volume 'Advances in Solar Energy Technology' is to consolidate all the relevant latest information available in the field of solar energy (applied and theoretical in nature) and to as sist both the students ( i. e. undergraduate, postgraduate, research scholars etc.) and the professionals (i.e. consulting, design and contracting firms). I have discussed each and every topic in depth rather than a cursory overview. All the material required on a particular topic is included in the chapter and I have wherever possible given useful relationships in equation, graphical and tabular form. It is hoped that this completed Solar Energy Technol ogy will serve the best source material in this field. The first chapter deals with the evacuated tubular col lecors suitable to operate at a temperature of about 150 DegreesC with a daily energy collector efficiency in excess of 40 per cent. These collectors thus would be useful for efficient operation of Solar Airconditioning System, Power Generation and Process Heat System. Various advanced features like vacuum insulation, selective black coating, anti-reflective coating, heat pipe, cusp reflector, etc., used in designing this advanced type of collector are discussed separately in this chapter. Transient mathematical model for its perfor mance prediction and different designs of evacuated tubular collectors commercially produced in different countries of the world are described in brief to give the reader a good picture about their scopr and working.

Energy Storage not only plays an important role in conservinq the energy but also improves the performance and reliability of a wide range of energy systems. Energy storagp. leads to saving of premium fuels and makes the system morA cost effective by reducing the wastage of energy. In most systems there is a mismatch between the energy supply and energy demand. The energy storage can even out this imbalance and thereby help in savings of capital costs. Enerqy storage is all the more important where the enerqy source is intermittent such as Solar Energy. The use of jntermittent energy sources is likely to grow. If more and more solar energy is to be used for domestic and industrial applications then energy storage is very crucial. If no storage is used in solar energy systems then the major part of the energy demand will be met by the back-up or auxiliary energy and therefore the so called annual solar load fract]on will be very low. In case of solar energy, both short term and long term energy storage systems can be used whjch can adjust the phase difference between solar energy supply and energy demand and can match seasonal demands to the solar availability respectively. Thermal energy storage can lead to capital cost savings, fuel savjngs, and fuel substitution in many application areas. Developing an optimum thermal storaqe system is as important an area of research as developinq an alternative source of energy.

H.P. Garg Centre of Energy Studies Indian Institute of Technology Hauz Khas, New Delhi 110 016 India Heating of water using solar energy is not new and by using a little science and technology in it, the solar energy can be utilized more effectively and economically for heating the water both for domestic and industrial applications. Solar Water Heaters are popular for the last three decades in countries like USA, Australia, Israel, Japan, India. This is the only solar energy application which is commercially, technic ally and economically viable and has been studied for more than 30 years in many countries. Technical advances in solar water heating have been very rapid in the last 30 years. These are becoming popular not only for domestic use but for large establishments like hostels, hotels, hospitals, industries such as Textile, Paper and Food Processing and even in heating of swimming pools in winter. In few instances the cost of solar water heating systems may be higher than those operated by electricity, gas or other fuel but over a period of time this is more than recovered by the savings in the cost of operations and maintenance."

The purpose of writing this three volume 'Advances in Solar Energy Technology' is to provide all the relevant latest information available in the field of Solar Energy (Applied as well as Theoretical) to serve as the best source material at one place. Attempts are made to discuss topics in depth to assist both the students (i.e. undergraduate, postgraduate, research scholars etc.) and the professionals (i.e. Consultancy, design, and contracting firms). Chapter 1 starts with a brief history of solar houses (active heating), one of the oldest and still the widely used application of Solar Energy. Various methods of build ing heating and other general aspects such as building form and functions are also described. Various components of active solar heating of building like solar collector, storage system, control unit, auxiliary heat source, etc. are discussed very briefly. Three types of solar active heating of buildings like Solar air systems, solar liquid systems, and solar assisted heat pump systems are discussed in detail in this chapter. Design details and performance of nine typical solar houses which are in use in different climatic conditions and using some newer concepts are also discussed in depth in this chapter."

The 'fuel crises' in 1972-73 generated world wide effort for the search for an Alternative Energy source to fossil fuels. Solar energy was identJfied as one of the alternatives to fossil fuels. On one hand the developed countries are trying to maintain their standard of living while the developing countries are trying to solve their industrial, social and economical problems to increase their standard of living. After this period a lot of Research and Development in the field of solar energy was carried out both in developing and developed countries and solar energy is utilized in domestic, agricultural and industrial sectors and also in the space. During the period of ,"Oil Crises" industrialized countries expended their activities in solar energy and substantial progress was made. In few developing countries seperate funding in the field of solar energy R&D was also provided through national and international, organizations. Time has now come when one should seriously look into the problems and screen, select, adapt, and manage emerging solar energy technology for its use in developing countries. Also the International Organizations will have to play a major role in this direction which may assist building up of a local solar energy R&D and manufacturing capabilities in developing countries which should be based on a long term but on necessary basis.

Energy Storage not only plays an important role in conservinq the energy but also improves the performance and reliability of a wide range of energy systems. Energy storagp. leads to saving of premium fuels and makes the system morA cost effective by reducing the wastage of energy. In most systems there is a mismatch between the energy supply and energy demand. The energy storage can even out this imbalance and thereby help in savings of capital costs. Enerqy storage is all the more important where the enerqy source is intermittent such as Solar Energy. The use of jntermittent energy sources is likely to grow. If more and more solar energy is to be used for domestic and industrial applications then energy storage is very crucial. If no storage is used in solar energy systems then the major part of the energy demand will be met by the back-up or auxiliary energy and therefore the so called annual solar load fract]on will be very low. In case of solar energy, both short term and long term energy storage systems can be used whjch can adjust the phase difference between solar energy supply and energy demand and can match seasonal demands to the solar availability respectively. Thermal energy storage can lead to capital cost savings, fuel savjngs, and fuel substitution in many application areas. Developing an optimum thermal storaqe system is as important an area of research as developinq an alternative source of energy.

This volume is the third in the series of the book entitled, 'Advances in Solar Energy Technology'. The purpose of writting this multiple volume book is to provide all the relevant latest information in the field of Solar Energy (Applied as well as theoretical) to serve as the best source material at one place. Attempts are made to discuss topics in depth to assist both the students (undergraduate, pos- graduate, Research Scholars) and the professionals (consulting, design, contracting firms). The third volume discusses the heating, agricultural and photovo1taic applications of Solar Energy. Chapter 1 deals with solar cookers, one of the important application area for developing countries. After discussing the history of solar cookers, eight types of direct solar cookers, two types of box solar cookers and two types of advanced solar cookers are discussed in detail. The performance studies carri d out on direct type and on box type solar cookers are also presented. A test procedure for rating a box type solar cooker is also introduced. The limitations and advantages of various cookers are discussed briefly in the chapter. Desalinated water for drinking purposes, for industrial and agricultural applications is required. The topic of Solar Distillation is discussed in detail in chapter two. Solar Distillation has a long history and in this chapter various kind of solar stills like conventional solar still, tilted tray solar still, wick type solar still, mUltiple effect diffusion solar still, multistage flash distillation, etc.

The main objective of writing the three volume 'Advances in Solar Energy Technology' is to consolidate all the relevant latest information available in the field of solar energy (applied and theoretical in nature) and to as sist both the students ( i. e. undergraduate, postgraduate, research scholars etc.) and the professionals (i.e. consulting, design and contracting firms). I have discussed each and every topic in depth rather than a cursory overview. All the material required on a particular topic is included in the chapter and I have wherever possible given useful relationships in equation, graphical and tabular form. It is hoped that this completed Solar Energy Technol ogy will serve the best source material in this field. The first chapter deals with the evacuated tubular col lecors suitable to operate at a temperature of about 150 DegreesC with a daily energy collector efficiency in excess of 40 per cent. These collectors thus would be useful for efficient operation of Solar Airconditioning System, Power Generation and Process Heat System. Various advanced features like vacuum insulation, selective black coating, anti-reflective coating, heat pipe, cusp reflector, etc., used in designing this advanced type of collector are discussed separately in this chapter. Transient mathematical model for its perfor mance prediction and different designs of evacuated tubular collectors commercially produced in different countries of the world are described in brief to give the reader a good picture about their scopr and working.