Abstracts Oral Presentations - Solar Food Processing Network

International Solar Food Processing Conference 2009 

Advancing towards achievement of Millennium Development Goals 

by training Rural and Tribal women in Solar Food Processing: A 

Hands on Experience at Barli Development Institute For Rural 

Women in Central India 

By Dr.(Mrs) Janak Palta McGilligan 

ABSTRACT 

Barli Development Institute for Rural Women has been working for sustainable community 

development through training of rural and tribal young women as human resources since 

1985.It attempts to stay aligned with the Millennium Development Goals. Following an 

initiative by Ministry of Non-Conventional Energy Sources, New Delhi University of Indore, 

Solar Brouke and Gadhia Solar and PLAGE one of its priorities has been promotion of solar 

food processing technologies in villages by training grassroot women in central India. During 

the past decade, the Institute has successfully trained them in using devices like SK14, 

Scheffler, 10&2.7 meters/ storage cooker, tunnel dryers for income-generating as well as 

domestic use. The training covered women’s socio-economical and human rights; healthy 

families and communities, successful management of self help groups; producing and 

marketing solar processed indigenous food and beverages, identification of locally available 

nutrients and inexpensive. Supplements for food. Technical side focused on operating, 

maintenance, assembling SK 14 kits, its importance and limitations. 

Institute has developed training materials and disseminated information specially designed 

for users of solar food processing technologies and able to transfer 00 SK 14 are in optimum 

use in the villages, and the users introduce, demonstrate and popularise the benefits of solar 

cooking among fellow rural women and neighbouring communities. One of the micro credit 

women group from SIRDI, trained by Barli is generating regular income. 

Training of rural and tribal women has led to training of Solar Cooks for Solar Kitchens. 

trainers, interns from various universities, NGO’s and some local fabricators in solar 

engineering and food processing. 

The intensive skill training and its direct application leads to their advancement towards 

millennium goals such as eradicate extreme poverty and hunger ; achieve universal primary 

education; promote gender equality and empower women; reduce child mortality; improve 

maternal health; ensure environmental sustainability; develop a global partnership for 

development as revealed by the feedback from the users as they find it safe, and improved 

the quality of lives immensely – helping to break down gender barriers and elevate status 

within their respective communities. 

Keywords: solar food processing technologies, Barli, rural and tribal women, training, 

Scheffler, SK-14, manufacturing, dissemination 

1


Solar energy utilization in food processing industries in India and 

estimation of environmental benefits 

Gokul Ramamurthy and Ishan Purohit † 

Renewable Energy Technology Applications 

The Energy and Resources Institute (TERI) 

Darbari Seth Block, IHC Complex 

Lodhi Road, New Delhi – 110 003 

Tel. +91-11-24682100, Fax +91-11-24682144 

E-mail: ishanp@teri.res.in 

Topic(s) Addressed: Solar food processing and back-up systems, how to ensure 

sustainable energy supply 

Food processing occupies a unique position in the Indian economy in terms of the potential it 

offers for employment generation and the export earning. The Indian food processing 

industry, with an annual growth rate of 10 percent was valued at € 90 billion in 2005. A large 

variety of products including different types of meat, fish, fruits, dairy items, etc., are 

processed in the country. In any food process industry, on an average 50% of the energy 

input is in the form of thermal energy (in the form of steam or hot water ranging from 60- 

150°C) and at present different conventional and inefficient thermal energy technologies 

such as wood fired furnaces, stoves, wood-fired boilers are used to generate the necessary 

process heat. Use of conventional technologies contributes significantly to global warming. 

Therefore, reduction in greenhouse gas emissions can be achieved by substituting 

conventional technologies with renewable energy technologies such as solar thermal 

concentrators and solar water heaters. 

An attempt is made here to analyze the potential of different solar energy technologies in 

select food processing industries and hence an estimation of the GHG emission reduction 

achievable through gradual replacement of conventional technologies is undertaken. A 

comprehensive review of commercially available and new solar thermal technologies is 

presented and a description of their suitability in respective industrial thermal processes is 

discussed. A scenario based modeling software, LEAP is used to construct the study and 

analyze the possible outcomes on the basis of possible GHG emission reductions. 

Key words: Food Processing, Solar Energy, Solar Collectors, GHG Emission, LEAP etc. 

2


Learning to develop and transfer Solar Food Processing 

Technologies at Barli Development Institute for Rural women in 

India 

Abstract 

James R. McGilligan 

To be presented in 


Date: 14– 16 January 2009 

Last ten years of developing and transferring solar food processing technologies at 

Barli Development Institute For Rural women, has been a unique learning 

experience specially having no professional degree, no research and development 

funding, no technical infrastructure, no academic or technical students . In 1998 Barli 

Institute initiated development and transfer of solar technology as a support to its 

ongoing programmes of empowerment of rural and tribal women as a step towards 

sustainable development. This led to all the learning and acquisition of solar 

engineering skills, information and hands on experience of manufacturing from 

Wolfgang Scheffler and Heike Hoedt , Deepak and Shirin Gadhia ,Deiter and Imma 

Siefert,and Pro Sawhney.It involved taking training, researching, manufacturing, 

using ,testing, making mistakes and take corrective measures, improving 

developing, documenting , disseminating information and then imparting this training 

to locals as well as overseas volunteers .It also involved interacting with 

academicians and experienced technical experts persons about various ,technical, 

structural and social aspects related to functioning of these devices. As a result 

Barli Institute could manufacture and install as well as transfer 14 Scheffler dishes 

of 10 meters and designed made 5 large solar kitchens ,more than 300 SK 14 in 

villages and used and tested the only working model of a solar- storage cooker the 

only working model worldwide. It also manufactured 2.7 meters Scheffler dishes of 

different type, solar oven, tunnel dryers, and distiller and trained local and 

international human resources. Institute developed training and information manuals. 

This resulted Institute becoming a learning centre for civil society, government and 

NGO and educational Institutions, business and industry, political leadership. To 

share this learning experience, researching, developing solar gadgets and devices 

is very important but equally important to reach the users, training them and helping 

them after giving them technology are inseparable parts of technology transfer. All 

the solar related agencies and Institutions should work together. 

Keywords: .Learning, Manufacturing, Developing solar food processing technologies, 

Barli women, training, Scheffler, SK-14, users, dissemination 

3


CHOCOSOL: An experience of producing joy without generating 

malice 

Aline Desentis Otálora, Chocosol Cooperative. Sáuces #201-5, Col. Del Bosque Norte, 

Santa Lucía del Camino, Oaxaca, México, C.P. 68100. Tel. (951) 161 14 90, e-mail: 

HYPERLINK "mailto:chocosol@gmail.com" chocosol@gmail.com. 

Topics addressed: Packaging, local and international marketing 

Introduction 

Chocosol was born of a search for applications for the “Fuego Solar” (Solar Fire), but with 

time it became a project in its own right. Its slogan, “We produce joy without generating 

malice,” sums up the cooperative’s philosophy. Its goals always looked to establish networks 

of fair trade, innovations in appropriate technologies, and recycling of someone else’s 

garbage. The cooperative also sought to reclaim traditional technologies, and to manage 

scales that would guarantee its sustainability without having to turn to mass-production. 

Eventually this eco-company came to benefit more than 15 people. 

A story of experiences 

The technology that we used consisted in the “Fuego Solar”, developed by specialists in 

alternative technology. It is comprised of a large wall of 52 mirrors, cut and pasted in such a 

way that they reflect and concentrate rays of sunlight in a focal point that measures one 

square foot. On a sunny day the focal point reaches a temperature of more than 900 °C in a 

matter of seconds. The Fuego solar can be used to roast grains, but also to cook, bake, grill, 

or boil water, depending on the design of piece that is placed behind the ceramic glass of the 

focal point. 

We came to process some 160 kg of cacao, 67.5 kg of peanuts, 70 kg of sugar and 9 kg of 

amaranth each year. This yielded some 220 kg of our signature chocolate called “Oaxacan 

Crunch”, 27 kg of dark chocolate and approximately 10 kg of pure baking chocolate yearly. 

The first step in the process, after acquiring local organically produced ingredients, was to 

roast the cacao and peanuts in the solar roaster. Secondly, the paper-like shell had to be 

peeled from the cacao nib. Recycling different kinds of containers, we attempted to design a 

tool for peeling the cacao. The prototypes were, however, insufficient, because too much 

cacao was lost and bits of shell remained in the clean cacao. We finally opted for peeling by 

hand, feeling that it was allowed us to carefully select the best beans. Because it was also 

the slowest way to peel, we decided to reduce the aims of our scale of production to 13 

kilograms of chocolate per batch. 

The third step was to grind the ingredients. The sugar was milled in a stone metate, a 

traditional grinding stone made of volcanic rock, while the cacao and peanuts were milled in 

a bici-molino, or bicycle-powered mill. This innovative design adapts a manual mill to the 

chain ring mechanism of a bicycle, and allowed us to mill some 15 kg of grain an hour while 

realizing healthy aerobic exercise. The technology of this and other bicycle machines was 

brought to Oaxaca from Guatemala by technicians with great experience, and is currently 

4


developed there in CACITA, (Centro de Aprendizaje, Capacitación e Investigación en 

Tecnología Alternativa). 

Next, all ingredients were ground together in an electric mill, and the resulting chocolate was 

“conched” in a solar pot called the “Olla Solae”. This consists in a black pewter pan inside a 

topped glass pot surrounded by seven screens of metal panels that direct the sun’s rays 

toward the pot. 

Cacao is a delicate material and we learned volumes about its processing with time. Heat in 

excess harms the chocolate, and if it is covered it acquires a bitter flavor. Without a small 

amount of water in the conching, which should never come into physical contact with the 

chocolate, the product becomes acidic and dries out. We discovered that by leaving the pot 

uncovered, and placing a small amount of water between the two containers, these issues 

were resolved. 

The texture of a good chocolate depends, in large part, on the length of time it is conched. 

With the solar pot, it was possible to prolong this process for some 8 hours or more, since 

the solar pot maintains the product hot for awhile after taking it out of the sun, and can 

maintain its liquid state if constantly stirred. 

After conching, we poured the chocolate into molds made of recycled PET bottles and cutand-stapled 

tetrapak containers, making 200g bars that were then chilled in a freezer. 

Tetrapak also served to make trays for the maneuvering the chocolates in this phase of 

production. 

The packaging was always a limiting factor. Looking for a package that would not generate 

garbage, we tried using brown paper, wax paper, and corn husks. As all of these 

presentations proved very delicate, it was difficult to commercialize Chocosol outside of the 

city of Oaxaca. 

Unfortunately, competition from industrialized products, costs of production, the wrapping 

that limited commercialization and the varied social conflicts that affected Oaxaca in recent 

years, forced the members of the cooperative to abandon the project in order to look for 

other means of subsistence, expecting the right moment to retake it. 

Chocosol is an unregistered brand, which identifies itself as “Copy Left”, a system within 

which whomever shares the idea can use the name and logo of the brand, under the sole 

condition that solar reflectors are used for roasting the grains. One example, “Chocosol 

Toronto”, in Canada, is an establishment where different kinds of chocolate are made of 

cacao imported from the state of Chiapas, Mexico, which is roasted with a “Fuego Solar”. 

5


Ten years of experience with the 

mobile solar kitchen and pancake shop 

Dr. Michael Götz, ExSol – Expertise en cuisine solaire, 15, rue des Gares, 

CH-1201 Genève, exsol@cuisinesolaire.com, 0041 22 734 734 1 

Topic(s) addressed: Examples of solar food projects, grassroots projects 

1. Introduction 

For more than ten years, the mobile solar kitchen / pancake shop (owned by the association 

GloboSol in Switzerland) has been used every summer in Central Europe to prepare 

pancakes on ecological fairs and music festivals and to feed youth groups in summer camps. 

The kitchen is part of our promotional work to spread solar cooking in Europe, but the 

campaigns have to be auto-financed by the sales and rental fees. This paper resumes what 

we have done and learned in these years. 

2. Summary 

2.1 The mobile solar kitchen 

The “mobile solar kitchen” is a car trailer with an integrated complete kitchen, equipped with 

two Scheffler cookers, box cookers, a 'hay box', etc. It has been constructed in 1997 after the 

donation of the trailer by its German manufacturer (Koch). Initially, it was meant to be rented 

without staff, an idea which proofed to be unrealistic soon. In every summer since more than 

ten years, it has been used on behalf of the Centre Neuchâtelois de cuisine solaire CNCS (and 

its successors ExSol and Solemyo), of ULOG Freiburg and on behalf of the owner, the 

association GloboSol. The way of auto-financing the campaigns (including small remuneration 

for the team) through rental fees and food sale will be explained in the paper. 

2.2 First use: mobile pancake shop 

Every summer, the mobile kitchen is used as pancake shop ('crêperie solaire') on music 

festivals and ecological markets and fairs. Music festivals have been chosen as 'target market' 

in order to reach young people and also 'outsiders' with our message; all too often, ecological 

events preach to the convinced. Some examples of festivals and average sales numbers will 

be given and the concrete organisation of our work will be described. 

2.3 Second use: mobile kitchen for summer camps 

In the first years, the kitchen has also served as 'catering service' for parties and ecological 

events. We prepared dishes like couscous, chilli con carne, soft cheese with potatoes, curry 

with rice, coffee and tee. Slowly, we moved from single day catering to weekly engagements to 

provide food for youth groups 3 times a day during summer camps (20 to 40 people). Most 

bookings are youth camps from Greenpeace's 'Solar Generation' youth campaigns. Examples 

will be given and the interaction between the rental crew (us), the organisers of the camp (an 

NGO) and its participants are discussed. 

6


2.4 Technical issues 

Almost as important as the solar equipment is the way how to handle bad weather and 

reduced sunlight in the late afternoon. Besides the solar cookers listed earlier, the kitchen is 

equipped with a unique cooker using wood 'pellets' (chips of compressed sawdust) as a 

second renewable energy source, and also two standard propane gas stoves. For pancakes, a 

special Scheffler cooker equipped with a heat storage unit based on a phase change material 

(metallic tin) can be added to the kitchen. Technical details, our experience with these devices 

and how to combine the different energy sources will be shown. 

The mobile solar kitchen selling pancakes 

on an ecological fair. 

Greenpeace volonteers preparing food for 

their group in a youth camp. 

References: 

'The 'solar crêperie' - Promotion of Solar Cooking by Selling Pancakes', Michael Götz, Paper 

presented at the 'Encuentro Solar 2002' in Benicarlo, Spain in June 2002 

'Liquid Tin Heat Storage for Scheffler Parabolic Cookers', Michael Götz, Paper presented at 

the 'Encuentro Solar 2003' in Benicarlo, Spain in June 2003 

7


Microenterprises in Solar Food Processing technology- A case 

study 

ABSTRACT 

S. L. Kumar, D. J. Rao, M. Ramakrishna Rao 

Society for Energy, Environment & Development 

Hyderabad- 500033 

With the development of commercial technology in cabinet dryers, a new economic social 

activity emerged out in the rural areas in the field of agri- horticulture through 

processing of fruits, vegetables, spices, medicinal plants on micro level. Ffifty food 

products of fruits and vegetables are processed in SEED commercial dryer on pilot scale by 

the application of food science and technology techniques for long shelf life and preservation. 

The technology is successfully commercialized through establishing the rural micro 

enterprises in 13 States in the country, starting from Ladakh in North to Trivandum in 

South. These enterprises not only generate the income and job. Opportunities to rural 

women and unemployed youth but also process the products with zero energy costs and with 

clean green energy. This obtained a recognition from Ministry of New & Renewable Energy, 

Government of India and obtained a sanction of 50% subsidy on the cost of dryers. The 

importance, strategies and the promotional methods of solar food processing products in the 

domestic and export markets are discussed in this paper. 

8


Promotion of SK14 Solar Cookers through an Eco Center. 

Case Study of a Unique North-South Co-operation 

Dr. Mrs Shirin Gadhia, , Eco Center ICNEER, 801, Rudraksh Appartment, Halar Road, 

Valsad 396001, Gujarat, India. 

Tel. : 0091-2632.222423 ; Fax : 0091-2632-236703 

Email : icneer@yahoo.co.in Webpage : www.icneer.org 

Topic: Examples of solar food projects : successes and hindrances, networking and 

cooperation 

1. Introduction: 

Eco Center ICNEER is abbreviation for International Center for Networking, Ecology, 

Education and Re-integration. It is an NGO set up to promote sustainable development 

which takes both ecology and economy into consideration. It provides a platform for North- 

South and South-South dialogue. 

At ICNEER, we address several target groups ranging from children to youth to adults of 

various professions including housewives and farmers as well as Government Organizations 

and Non Government Organizations from rural and urban areas as well as overseas. 

Besides creating awareness on conservation of natural resources and sustainable organic 

agriculture we have also prepared posters and teaching material on Renewable Energies 

especially solar cooking. 

During one of our overseas lectures, orgnaied by INETRSOL and PLAGE, the Austrian 

NGO’s, while we were addressing school children in Salzburg, a question was raised about 

the acceptance and how widespread is the use of domestic parabolic solar cookers. On 

learning of their limited usage due to its non-affordability, the children decided to help. 

Under the guidance of equally enthusiastic school teachers, the children raised funds to 

purchase K14 solar cookers. Subsequently the school children prepared solar baked cakes, 

bread, biscuits and soups and sold them on “Market days” in Salzburg and thus collected the 

funds for donating solar cookers to India. 

When Austrian government heard about this unique initiative, they decided to give matching 

funds. Hence the first Project “2 X 50 Solar Cookers for Rural India ” was started. 

2. Summary : 

The money collected was given to INTERSOL, On recommendation of Eco Center ICNEER 

the funds were Barli Development Institute for Rural Women in Indore in State of Madhya 

Pradesh. Barli Group in turn distributed the Solar Cookers at nominal cost to tribal girl who 

were at their Institute after duly training them in its use. 

School children from St Johann also followed suite. Funds collected by the school children of 

St Johann and also from Stadt Gemeinde St Johann and other 5 local communities were 

made available to initiate the first smoke-free village called Bycenapally in Andhra Pradesh in 

co-operation with Jagadeeswata Reddy District Manager of NEDCAP the State Nodal 

Agency of State of Andhra Pradesh. 

Success of Smoke Free village had multiplier effect and now further three villages near by 

have also become smoke-free 

Now ICNEER has been trying to replicate the project in co-operation with, due modifications 

to suit local conditions, in other parts of India with local NGOs e.g. Veerayatan in Mumbai, 

9


in Maharastra, Kutch in Gujarat and Rajgadh in Bihar, Sisters and Fathers in Dharampur 

tribal belt in Gujarat, and initiated projects with them and the experience and difficulties faced 

would be shared so that further inputs from other solar is sought to fine tune the project. 

Our experience of how Solar Cookers can be used not just for cooking but for income 

generation by using the solar cookers for Food Processing for sale of these products for 

income generation will be shared 

With a Power Point presentation participants will be enlightened about the necessity for more 

Eco-Centers, sources for availability of various teaching material, wide range of income 

generation possibilities for women and youth. We will walk the participants through how this 

project evolved, so that others may also follow suite and we learn from other solar promoters 

experiences. 

10


Thematic studies for processing and preservation of food 

supplement, chilies and ginger by drying through solar energy 

Ranjita Bezbaruah Sharma 

Agriculture Specialist 

Action For Food Production-Guwahati 

Pub Sarania Bye Lane-4 

House no- 8, Guwahati-781003, Assam 

0361-2567650/2463373 [0] 

91-9435019659[M] 

E mail - atfg@afpro.org , atfguwahati@gmail.com , ranjitas@sify.com 

Topic area: Example of Solar Food Project: Success and Hindrance, Networking and 

Cooperation 

ABSTRACT 

A thematic study was carried out in two selected villages- Todaijang and Nongba of 

Tamenglong District of Manipur and three selected villages- Neotan,Neirong and Jatinkaike 

of Changlang District in Arunachal Pradesh by AFPRO Guwahati to promote the use of Solar 

Dryers among rural population which in turn would contribute to beneficial changes in 

women’s lives, in agricultural practices and in conservation of biomass. Two NGOs - 

Rongmei Baptist Association (RNBA), Imphal, Manipur and Seva Kendra, Khonsa, Arunachal 

Pradesh have been identified as the project implementing Partner [PIP] Different SHG 

groups were identified to implement the project. Adequate orientation have been provided to 

the members with the help of expert professional Resource agency to provide necessary 

technology support, technical advise in the field of Solar Energy Resources. Different types 

of Solar Dryers-tunnel type and chimney type were installed in selected villages. Training 

were imparted on operation & maintenance of solar Driers to PIP staff, SHG members to 

handling, operate, repair, maintain & manage solar Driers.. Exposure training also has been 

provided to the SHG members on preservation of gingers, tapioca along with packaging. 

Solar dryers for food products have been installed for the first time in these areas. SHG 

members used the dryers for drying various spices, fruits and vegetables such as turmeric, 

long melon, tapioca radish, banana, papaya, pineapple, maize, cooked rice, green leaf 

vegetables, cabbage, paddy and even meat apart from ginger and chilies. As King chilies 

production is very high in Manipur and there is a very high demand of it, women groups of 

Manipur utilized the dryer for drying king chilies. Previously the villagers used to dry the 

chilies above the firewood but gradually they have changed their tradition after installation of 

Solar Dryers and it saves time and energy. The solar dryer is appropriate to provide self 

employment for the family members especially women. The duration for drying differ from 

one item to another like 4-5 days for chilies 5-6 days for turmeric, 2-3 days for tapioca, 5-6 

days or sometime 2-3 days for banana,3-4 days for radish,3-4 days for ginger, 3-4 days for 

bottle gourd, 2-3 days rice, 3-4 days meat etc depending on the weather condition.. The 

dried product under the Solar dryer can be kept for long duration without any deterioration. 

Using of the dryers also reduces the consumption of fire wood and reduces smoke pollution 

which directly effects the surrounding environment and also the persons involved during the 

process of drying. Introduction of this thematic study also results in strengthening of local 

institutions and awareness generation. The process has been developed for collection of 

minimal amount from the individual who are interested to dry their product which generate an 

income for the SHG. Hindrance like hail storm which damage the solar dryer’s polythene and 

fans became a major problem. Networking with the marketing agency was also generated 

but the women groups were not able to meet the requirement of the marketing agency due to 

several reasons. The solar dryers installed at Changlang district of Arunachal Pradesh were 

not functioning well due to many reasons, hence to see the real impact, two tunnel types 

11


dryers has been shifted and installed at Mamziuram and Daisuang village of New Jalukie 

area of Nagaland under organization named RBA[Rongmei Baptist Association].It has been 

found that solar dried product for example bananas and tapiocas are more sweeter than the 

raw one. Solar dryers are vey useable and it will help the community to have nutritious 

processed food. 

12


Smoke-free villages with cluster approach and micro-finance and 

livelihood opportunities: Case Study of thee Villages in A.P. using 

solar cookers for food processing 

Sri Jagadeeswara Reddy, 

District Manager, NEDCAP 

10-161 Gandhi Road 

Chittoor 517001 

Email: solarreddy@gmail.com 

Solarreddy2002@yahoo.co.in 

Tel/fax: 0091-8572-233187 

Topic: Local marketing / grassroots projects / village industries 

1. Introduction : 

We will share our success story of Smoke-free village concept where with innovative 

tools like micro-financing, income generation and by motivating, training the villages 

we have with unique cluster approach converted 3 villages till date into Smoke-free 

villages and now villagers cook with Solar Cookers and Biogas. Solar processed food 

is marketed in local bazaars for income generation. 

We have also involved Students and staff of Women’s Science Colleges and 

University of our region in our project for training, monitoring and scientific study 

2. Summary: 

With proper system in place i.e. funding, team for installation and motivation and 

marketing support by involving village committee a model has been created that is 

multiplying. 

The presentation will be in form of Power Point Presentation and concrete examples 

will be narrated 

13


Solar community bakeries on the Argentinean Altiplano 

Christoph Müller, Fundación EcoAndina; Coronel Arias 1091, 4600 S.S. de Jujuy, 

e-mail: chris@hc-tronic.de, Tel. 0054/(9)388/4337154 

1. Abstract 

Financed by a BMZ project (German Ministry for Technical and Economic Co-operation) five 

solar community bakeries amongst other installations where build up in villages in the 

Argentinean Altiplano. The aim is to replace the use of tola bushes as heat source in 

traditional ovens. Each family bakes its bread one time per week in its own adobe oven, 

using in average 30 kg of tola. Due to the extreme arid climatic conditions and growing 

population, the impact of firewood collection is more and more visible. To protect the sparse 

vegetation, a solar bakery oven was developed using a fix focus Scheffler reflector with 8 m² 

reflector area. The oven has a volume of about 200 liters. With an input power of about 3 kW 

it reaches temperatures of up to 350 °C. Alternatively the oven can be moved aside on rails 

and permits the use as cooking plate. For cooking use, a new type of cooking plate was 

developed, using a ceramic stove top to protect the secondary reflector from food dropping 

down. 


The NGO EcoAndina has been working in close co-operation for around ten years with 

Solar-Global e.V. in Germany and the cooperative Pirca in Argentina. Solar Global was 

founded by the Solar-Institut Jülich in order to promote newly-developed “adapted solar 

technology” in developing countries in a quicker and more direct way. This was made 

possible by financial support, building of prototypes and organisation of training courses in 

partner countries. The development of prototypes took place in close co-operation with the 

local project partners and users. In this way, misguided development was avoided and the 

user’s needs were not overlooked. The aim is to bring into use simple solar devices, which 

do not depend on imported materials but only on the know–how of manufacturing on-site. 

This way, the living conditions of the people in terms of economic welfare, general health and 

ambient protection can be vastly improved. The projects have been financed by private 

sponsors, members of Solar Global, the Ministry for Technical and Economic Co-operation 

(BMZ), member organizations and the local project partners. 

References 

See www.hc-solar.de or www.solar-bruecke.org for construction plans of the bakery oven. 

14


Title: Agave syrup production – a sweet tradition goes solar 

Gregor Schapers 

Trinysol 

El Sauz 

42370 Cardonal / Hidalgo 

Mexico 

0052 – 1771 1199 280 

gregoriomexico@gmail.com 

Topics: 

- Local solar food processing technologies 

- Local marketing / grassroots projects / village industries 

- What is solar food ? / definition and quality standards ? 


A group of woman in the village San Andres 

(Mexico) startet about 15 years ago with the 

production of a sweet agave syrup. They formed 

a cooperative to make the syrup of the juice of 

the green agave. For this purpose they need a 

huge amount of energy to cook the juice and 

concentrate the syrup. To heat up their big 

cooking pots they used big gas stoves. 

After some nonsatisfying attempts to process the 

syrup with small solar stoves (SK-14) in 1999, 

new efforts in 2005 with Schefflerreflectors wer 

succesfull. 

In 2008 started the production of solar agave 

syrup with six 10 m2 Schefflerreflectors in a new kitchen building. 

2. Summary 

2.1 Cooperative 

The green agave, the Maguey, is one of the 

oldest plants cultivated in Mexico. The culture of 

the Ñhahñus, the native people living the 

altiplano about 200 km in the north of Mexico 

City, is aligned with the cultivation of this plant. 

Every part of the plant gives a use to the people 

and that is the cause why you can find large 

plantations of magueys in the altiplano. 

All the families in the village San Andres have 

plantations of magueys and the majority earn 

their money with selling "pulque" in the towns 

nearby. Pulque is the "agave beer" of Mexico. 

The Maguey needs about 7 years to grow up and than you can extract about 1 up to 8 

Liters of the juicy liquid "Aguamiel" of each Maguey each day. The pulque is a result of 

fermantation of the aguamiel an it contains a little amount of alcohol - like beer. In 

present every day its more difficult to sell pulque because it has to compete with beer and 

beer is aggressevly advertised even in the smallest village. 

15


About 15 year ago a group of 25 woman in San Andres startet to search for 

alternatives to help the economy of their familys. They learned to make the agave 

syrup of the aguamiel instead of pulque. 

In former times agaves sirup was the most important sweetener in North and Centra 

America. After the arrival of the Spains 500 years ago they substiute the agave 

sweetener for sugarcane which they brought with them from europe and startet huge 

plantations in Cuba an Mexico. 

For the woman in San Andres the production of agave sirup was succesfull and they could 

find a small regional market for their product. They build a small kitchen with big gas stoves 

where they cook the aguamiel and they bottle the agave syrup. 

The woman had the aguamiel and time to work - the biggest expenses were the 

purchase of gas for the cooking process. 

In 1999 the woman make some tests with the solar cooker Sk-14. They learned that its 

possible to concentrate the aguamiel with solar energy an that you can make the agave 

syrup with this "new" energy. But on the one hand the amount of aguamiel you can cook 

with a Sk-14 is small and on the other hand they are accustumed to cook very clean what 

is difficult outside the kitchen in the desert where it is very dusty. An other important fact 

was that the woman did not want to cook outside the kitchen in the sun. 

So they continued with the use of their gas stoves. 

In 2005 we made a new attempt with a 8m2 - Schefflerreflector and this attempt had 

success. After some time of testing, evaluation and providing confidence the woman 

decided to change to solar energy with Schefflerreflectors. 

The swiss organisation Globosol helped to build six 10m2 Schefflerreflectors and a new 

kitchen building in San Andres which was installed in 2007/2008 and starts working in 

august 2008. The Woman can cook each sunny day about 250 litres of aguamiel with the 

Schefflerreflectors. That is the average of the amount of agumiel they cook with gas in one 

day. 

It was not difficult for the woman to learn how to cook with the solar energy because the 

design of the Schefflerreflector allows them to cook like they habitual cook in their gas or 

fire stoves - all the heat is coming from downside to the cooking pot. 

The solar agave syrup is brighter than the 

syrup cooked with gas which is darker 

because more sugar is caramelized. The 

flavour of the solar agave syrup is sweeter 

and you can use it for cooking and sweeting 

without changing the original taste of the 

food. 

16


Solar Project Gambia 

Elena Steger-Kassama, Solar Project Gambia, postal address, 

mail@solarprojectgambia.com, tel 00220-7053822/002209712915 

Topic(s) addressed: Solar project examples and grass roots projects 


The Solar Project Gambia (SPG) is a project that is trying to work as an example and an 

information centre concerning the direct use of the sun for cooking, baking or drying. It is 

producing its own solar dryer and solar cooker. It is divided into three parts the bakery, the 

carpentry and the restaurant. Our aim is to make solar food popular in the country and help 

against the deforestation. As well we inform about healthy food and want to help against the 

malnutrition. The project is so concepted that it works as a training and information centre 

concerning the use of the direct sun light. It gives 8 local people a work and income from 

producing solar food or equipment. 

Our slogan is “Solar Project Gambia cook with the power of the sun safe money and firewood!” 

Our service are, solar baking, solar cooking, solar drying and solar installations. 

The SPG is devided into three parts: 

Bakery Solar restaurant carpentry 

2. Summary 

2.1 Solar-Bakery: successes and hindrances 

The best example of success is the bakery and the restaurant. It’s a good practiced example 

how to make solar food popular. Trough our daily presentations in the street presenting 

delicious cakes and cookies in the solar cookers we could get a lot of people interested and 

curious. The bakery is an example how it is possible to generate an income with Solar 

baking. Our products are to be found along the coast side in different supermarkets and 

small shops as well we are selling along the beach side. 

The project is offering also a restaurant in a natural environment to serve the solar baked 

cakes or pastries. The project is including tourist city tours. The tours are a great opportunity 

for the visitors to get unforgettable memories of their holiday in Gambia and bring a small 

solar gift for their friends and relatives back home of the SPG. The feed backs are very 

positive. During this year we reached a lot. But we are facing hard times during the raining 

season the off season of the tourist sector. 

Therefore must be worked out new strategies how the project could still generate enough 

income for this time. 

17


Practical Application of Solar Tunnel Dryers 

Klaus Triebe, Elnatan (Association Inc. under section 21) P.O.Box 161 Calitzdorp 6660 

South Africa, elnatanagape@lantic.net, tel. & fax +27 /44 21 33 859. 

Topic addressed: 

* Solar food processing 


Solar Tunnel Dryers (STD) are weather protected food dehydration tunnels that dry 

food economically and hygienically 

2. Summary 

STD are used to dry fruits and fruit pulp as well as fruit juices, especially of fruits that 

would quickly perish. We therefore produce: 

Fruit Leather, 

Fruit Juice Concentrates 

2.1 Fruit Leathers 

2.1.1 Preparation of Drying moulds 

Simple wooden boards with an edging and lined with one-way plastic are used. 

2.1.2 Preparation of Fruit 

Washing, sorting and pre-cutting of fruit as a manual operation. 

2.1.3 Grinding of fruit 

Shredding or grinding of fruit with common household shredders and grinders. 

2.1.4 Mixing of fruit pulp 

Fruit pulp, sugar and preservatives are mixed by hand. 

2.1.5 Drying of fruit 

Volumetric measured fruit pulp is distributed equally into the moulds and dried in the 

STD in 2-3 days. 

2.1.6 Storage 

The fruit leather has to be fumigated in order to prevent damage through insects. 

Storage in cool rooms (approx. 12-14 degrees C.) for further conservation. 

2.2 Fruit Juice Concentrates 

2.2.1 Preparation of dryer. 

The dryer has to be equipped with an absolute level grid to receive the concentration 

moulds 

2.2.2 Concentration of juices in dryer 

Sterilised fruit juice is poured into moulds to a depth of 2-3 cm for evaporation. 50% of 

the water content is evaporated on the first day. Thereafter the evaporation slows down 

until the final stage of the concentrate is reached, depending on the requirement of the 

final product. (E.g. Juice Concentrate, Paste, or Juice Leather) 

18


Watermelon Processing in Triple Purpose Solar Integrated 

Device 

P.C. Pande 

Central Arid Zone Research Institute 

Jodhpur, 342003, India 

Email: pcpande@cazri.res.in 

Fax No. +912912788706 

Tel. NO. +912912786386 

Topic(s) addressed: Solar food processing and back up systems, how to ensure 


Introduction 

Drying of watermelon in solar dryers is somewhat difficult due to higher moisture content 

(97%) and probability of getting fungus during the night when the solar radiation are not 

available and it becomes worse if conditions are humid. At the same time during season 

there is a lot of wastage of the produce due to non -availability of an appropriate device 

to process it near the agricultural field. In view of this and considering the extensive 

experience in solar drying of different produce, attempts were made to process the 

watermelon crush for making candies by using novel three in one integrated solar 

device. 

Summary 

The integrated solar device, developed to use it as a water heater, cooker and dryer, 

comprises especially designed oblique shaped GI tank to hold water, appropriate 

geometry to use the device in stationary mode, double glazed windows with reflectors at 

the top and in the front side to utilize solar energy round the year, facility to operate the 

system as cooker on especially designed cooking cum insulting tray and four plastic pipe 

nipples with caps for facilitating the air circulation while using it as a dryer with built in 

storage. As a water heater, 50 L hot water of 50-60 o C could be obtained in winter 

afternoon while as a cooker food for a family could be boiled with in 2-3 hours (loading 

time 10 A.M). As a dryer, fruit and vegetables like ber, grated carrot, spinach, 

watermelon flakes, tomato slices etc. could be dehydrated efficiently with regulation of 

temperature during day time and continuation of the drying process even in the night 

through the solar heated water. The results of these experiments are discussed, which 

reveals that the same device can be used for three applications. 

In the experiments for making watermelon candies, the watermelon crush was first 

poured on small trays kept on the cooking tray, allowed it to be heated in cooking mode 

and then dehydrated by using the same device in drying mode. The hot water provided 

energy to continue the drying process during the night. It took 28 hours to dehydrate the 

watermelon crush. The dried pulp could be rolled in form of spherical candies. The 

candies were tasty and have long storage. These results of processing watermelon 

crush for making candies were encouraging and may find a real utility, both in domestic 

and commercial fronts. 

19


Studies on Fortification of Solar Dried Fruit bars 

G. Sarojini, V. Veena, M. Ramakrishna Rao 

Society for Energy, Environment & Development, 

Hyderabad - 500 033. 

The fruit bars specially Mango bars, processed in the novel and unique Solar 

Cabinet Dryer, Designed and Developed by Society for Energy, Environment & 

Development have become very popular in India. The technology developed in 

processing the recipe of the bars is studied in its Physico-Chemical properties, 

Nutritional facts and Organoleptic properties. To further improve the nutritional 

values Mango bar and Guava bars are fortified with proteins of Whey, Soya and 

Peas, Beta-carotene with carrot blending, ascorbic acid (Vitamin-C) and calcium 

compounds. The characteristics of solar dried bars and the enriched nutritional 

values were studied. The result of these investigations are reported and 

discussed. The sensory properties were also evaluated. 

In light of hard structure formed with various proteins, whey protein is found more 

acceptable. Calcium fumarate and ascorbic acid were preferred for enrichment 

of mango bar. For guava bar, Beta- Carotene enrichment was done through 

carrot, forming fruit- Veg bar. Some of the results are being incorporated in 

commercialized bars by enriching the SEED Mango bar. 

20


Solar Drying of mushroom using solar tunnel dryer 

B. K. Bala, M. A. Morshed and M. F. Rahman, Department of Farm Power and Machinery 

Bangladesh Agricultural University, Mymensingh-2202, Bangladesh 

e-mail: bkbalabau@yahoo.com 

• Topic(s) addressed: Local solar food processing technologies (oral presentation) 


Mushrooms are edible fungi of commercial importance and their cultivation and 

consumption have increased substantially due to their nutritional value, delicacy and flavor. 

It is rich in vitamins C, D2, B2, and Mg, P, Ca, dietary fibers and amino acids. Another 

important ingredient of mushroom is the polysaccharide compound beta-glucan, which 

enhances cellular immune function. But mushrooms are extremely perishable and the shelf 

life of fresh mushroom is only about 24 hrs at ambient conditions and 7-10 days even with 

refrigerated storage because of its high moisture content and rich nutrients that spoil easily 

and quickly. Again, various physiological and morphological changes occur after harvest, 

which make these mushrooms unacceptable for consumption. Therefore, mushrooms are 

usually dried to extend the shelf-life. Hence, these should be consumed or processed 

promptly after harvest. Drying is one of the important process by which mushroom is being 

preserved. As mushroom is very sensitive to temperature, choosing the right drying method 

is very much important. 

The growers of mushrooms dry mushroom under sun, which yields unhygienic and poor 

quality dried products. Due to long drying time and over-heating of surface during sun 

drying, the problems of darkening of color, loss in flavor and decrease in re-hydration ability 

occur. Mechanical driers can be used, but it requires fossil fuel and electrical energy. 

Since drying is an energy conservation process, it is not economic to use mechanical 

dryers. All the areas in Bangladesh receive abundant of solar radiation and it is 

environmentally sound. Solar dryers have the potential for adoption and application in 

Bangladesh. 

Solar drying can be considered as an elaboration of sun drying and it is an efficient system 

of utilizing solar energy. Many studies have been reported on natural convection solar 

drying of agricultural products. Considerable studies on simulation of natural convection 

solar drying of agricultural products and optimization have also been reported. The success 

achieved by natural convection solar dryers has been limited due to low buoyancy induced 

air flow. These prompted researchers to develop forced convection solar dryers. Many 

research and performance studies have been reported on forced convection solar dryers. 

Studies on simulation and optimization of forced convection solar tunnel dryers have also 

been reported. Numerous tests in the different regions of the tropics and subtropics have 

shown that fruits, vegetables, cereals, grain, legumes, oil seeds, spices, fish and even 

meat can be dried properly in the plastic covered solar tunnel dryer. 

Several studies have been reported on drying of mushrooms. Although many studies have 

been reported on solar drying of fruits and vegetables, limited studies have been reported 

on solar drying of mushroom. 

Although very limited studies have been reported on solar drying of mushrooms, no study 

has been reported on solar drying of mushroom using solar tunnel dryer. This paper 

presents a systematic experimental study of solar drying of mushroom using solar tunnel 

dryer. 

2. Summary 

Solar drying of Mushroom was conducted to investigate the performance of the solar tunnel 

dryer for drying mushroom. The dryer consists of a transparent UV established plastic 

covered flat plate collector and drying tunnel unit. The drier is arranged to supply hot air 

directly into the drying tunnel using three d.c. fans powered by a 40 watt solar module. The 

21


products to be dried are placed in one layer on a wire mesh in the drying tunnel to receive 

energy from both hot air supplied from the collector and from the incident solar radiation on 

products. During the experimental period the minimum and maximum solar radiation were 20 

W/m²/day and 170 W/m²/day respectively. The generated voltages for the 40 W solar 

modules were 4.5. V to 14.8 V. Temperatures in the drying chamber varied from 37.0° C to 

66.5° C. During the high insulation period more energy was received by the collector which 

was intended to increase the drying air temperature but it was compensated by the increase 

of the air flow rate. During low solar insulation period less energy was received by the 

collector and the air flow rate was low. This resulted in minimum variation of the drying air 

temperature throughout the drying period. 

Fig. 1 shows the comparison of the variations of the moisture content with the time of 

mushroom during solar drying with those of sun drying for a typical experimental run. 

Mushroom was dried from about 89.41% to 6.14% moisture content (w.b) in about 8 hours. 

In the same drying period, the moisture content of Mushroom reduced from 89.41% to15% in 

the traditional sun drying method. 

Moisture content, % (w.b.) 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Solar 

Sun 

9.30am 

10.30am 

11.30am 

12.30pm 

1.30pm 

2.30pm 

3.30pm 

4.30pm 

Time of day 

Fig.1 Comparison of the variations of the moisture content with the time of mushroom 

during solar drying with those of sun drying for a typical experimental run 

In addition, the Mushroom being dried in the solar tunnel drier were completely protected 

from rain, insects and dust, and the dried mushroom were high quality dried products terms 

of flavor, color and texture. As the fans are powered by a solar module, the drier could be 

used in rural areas where there is no supply of electricity from grid. 

22


Solar food processing in Afghanistan 

Dipl.-Ing. Mohammad Sabur Achtari 

Afghan Bedmoschk Solar Center e.V. 

Im Käppelefeld 37 

D-79189 Bad Krozingen 

0049-7633-949706 

m.s.achtari@web.de 

Topics 

Local solar food processing technologies 

Solar food: quality measures and indicators 

Examples of solar food projects: successes and hindrances 


The capital Kabul lies approx. 2300 m above sea level, on the edge of the Hindu Kush. 

The weather in the course of the seasons is similar to that of central Europe, only much drier. 

The intensive sunshine of 250 to 300 sunny days a year is a very good condition for the use 

of solar energy. We have established our main centre for solar food process in Kabul and 

from there we will enlarge our activities in all surrounding villages of Afghanistan. 

Preference for presentation: Power point presentation and exhibit of packed dried 

vegetables and dried fruits. 

Drying fruit and vegetables: 

People live on agriculture and sell the surplus of the cultivated wheat. Potatoes and onions 

are grown to a lesser extent. Almost no machinery is available for agriculture: ploughs are 

drawn by cows. In the recent years many families went over to growing fruit, as this provides 

a better income. The fruit is often sold directly from the trees, however for a lower price than 

for harvested fruit. People try to make use of the short fruit surplus during harvest time by 

drying apples and apricots on their roofs. To a lesser extent people dry vegetables as a 

winter stock. Except for drying no other methods of conservation are used. 

Selling the agricultural products and vegetables (fruit) results in very little income. 

2. Main conclusions 

In August 2005, a solar dryer, of a tunnel type, was built. It uses direct solar radiation. To 

create hot air in the collector part of the equipment with such design, a PV-driven fan 

provides the necessary air-flow over the fruit. It has been tested drying apricots. The 

handling of the drier is very similar to the traditional methods, as the fruit is simply spread on 

a flat surface. In this drier, 7 kg of apricots are dried within 3 to 4 days. This is very similar to 

the method, where the fruit is spread in open air. But the quality is much better through a 

23


more hygienic drying process: the fruit is protected against dirt, dust and animals. We 

decided to start with small driers of 2m x 1m. This makes it easier for projects or farmers to 

get to know this new technology, without making a large investment. The small device can 

easily be carried and placed on roof tops. If more drying surface is needed, further drier 

modules of the same size can be added or the decision for a large drier can be made. A 

small ventilator bought on the local market is used to force the air through the drier. One 5 W 

PV panel is enough to run a solar drier of that size. Five more driers have been built for the 

second phase of the project, which includes packing the dried fruit in an attractive, sealed 

bag and finding ways to sell the product. After the first tunnel drier was tested by ABS, the 

cooperatives showed interest and took the drier for their own tests. In the third step we have 

produced 21 of those driers. 

Purpose of the work 

By introducing the solar driers, ABS wants to address following of its aims: 

• Creation of jobs and income within the village for women 

• Increase of product quality 

• Possibility to reduce migration through local income generation 

• Increase of storage life of vegetables and fruits 

• Use of renewable energy and thus saving the environment 

• Production of solar tunnel drier and Scheffler reflectors and creating jobs 

• Making women’s work easier by this new equipment (as the driers protect fruit from 

dust and sand) 

• To create a model of solar drying system that will spread 

In August 2008, ABS has implemented a project with 21 of these solar driers to the farmers 

of the Logar provinces including a training in use of driers and packing of dried goods. 

If farmers show interest, a bigger version of the tunnel drier will also be offered. 

Methods, Innovations, Results (as appropriate) 

We use the Scheffler reflector for making bread, marmalade and cake. 

We use solar tunnel driers for drying vegetables and fruits. 

We produce this locally, in Afghanistan. 

The result shows very good quality, thus we can sell the product better. 

Capacity building, offer for training. 

Establishment of resource center/training center/testing center. 

Scheffler Reflector 

In summer 2006, two reflectors of 10m² each were built in our centre in Kabul and are 

installed there for demonstration purposes. Advantages of the system: Environmental 

protection and alleviation of women’s work. Inhalation of poisonous gases from open wood 

fires and burning plastic, tire of cars, are prevented. 

Local co-workers learn methods and procedures of manufacturing marmalade and cakes. 

The aim is to put production and sales into local hands at a later stage. 

We faced problems in getting bottles for marmalade. At first we filled used marmalade bottles 

that we could sell to relatives and known people. But it was impossible to do so in the open 

market, because the bottles were marked with expired stamps and were in no good condition. 

We could have sold a lot more of our homemade marmalade, if we had new bottles. 

Cake can be sold, too, but we had not installed a thermometer in the oven, so the 

temperature could not be controlled. We now have installed one and are sure to get quality 

control. 

24


All India Women’s Conference Experience In Using Solar Driers 

Towards Income Generation For Needy Women 

Ms.Lalita Bala krishnan Email:-lalitabalakrishnan@gmail.com 

Ms. Chandra Prabha Pandey Email:-chandrapabhapandey@yahoo.com 

AIWC, 6 Bhagwan Das Road, New Delhi-11000,Tel-23389680,1165,Fax(91-11) 23384082 

E-mail:aiwcctc@nda.vsnl.net.in Website:www.aiwc.org 

INTRODUCTION 

AIWC is one of the oldest and renouned womens, not-for-profit organization working for the 

empowerment and development of womens in all aspects. Started in 1927, AIWC has been 

headed by a galaxy of eminent women including Dr. Rajkumari Amrit Kaur, Vijay Laxmi 

Pandit , Masooma Begum and others. Since then AIWC has been continuously conducting a 

large number of programmes towards the betterment of women. 

Identified as one of the nodal agencies with direct funding by the Ministry of Non 

conventional Energy Sources(MNES) GOI now known as Ministry of New Renewable 

energy, (MNRE), AIWC has been implementing various government programs such as 

“National Programme of Improved Chulha-NPIC, National Programme of Biogas 

Development-NPBD”, Solar Thermal and PV disseminations and energy conservation for 

over 2 and half decades, covering the entire nation through AIWC’s 500+ branches and 

some partner NGO’s realizing the great need for food security and stopping of wastage of 

fruits, vegetables and spices at the village level due to their nature of perishability and also 

not having proper linkages to markets. 

SUMMARY 

A large quantity of fruits and vegetables are wasted in the rural areas for want of immediate 

market facilities or for processing. By using the solar driers almost all produce including 

fruits and spices could be made into value-added products which will fetch enhanced income 

as well as increase the shelf life of the products. 

AIWC decided to adopt the technology developed after ten years of R & D by the Hyderabad 

based NGO-“SEED” and identified their SDM 50 solar drier which works through both 

thermal and photo-voltaic modes, towards achieving the following objectives:- 

a) To create awareness among women to utilize clean and affordable energy 

services for productive and consumptive uses. 

b) To develop capacity of the rural women's groups to participate in the 

promotion and dissemination of solar driers in the community. 

c) To improve the livelihood status of rural people through value addition of farm 

produce by using solar dryers in processing of food products. 

25


d) To mainstream women in decision making process related to the choice and 

adoption of the energy technologies appropriate for drudgery reduction and 

improvement of their social and economic status 

e) To share the results/outcomes of the project with the participating countries 

for further replication elsewhere in South Asian countries. 

First, with the Small Grants-Integrating Poverty Reduction in Programs and Projects of 

Asian Development Bank, we did a program entitled “Income Generation through solar 

driers for women” through branches in four states- Chennai, Andhra Pradesh, Kerala, 

Delhi. In this we evaluated the system and for one whole year we had noted in a 

specially prepared matrix, the full detail of the production of drying fruits like mango, 

Guava , pine apple and others, preparing desiccated coconut, drying of spices etc. The 

produce used were those which were available in each of the project and at the end of 

the year it was proved that using solar drier diligently for the produce in season will help 

to create added income for the needy women. 

Following this, AIWC had participated in a joint project with CRT(Centre for Rural 

Technology-Nepal) and conducted an Action Research Project with the grant from 

USAID-SARI III project. This project-“Capacity Building for Women Through Solar Driers” 

was conducted in Nepal where they had trained a number of women in the construction 

and assembling of low cost solar drier, using their local produce: while AIWC up scaled 

the project in Chennai, Delhi, and kerala. The rural women have been very open and 

enthusisastic in learning these technologies and were all very keen to start income 

generation program in their respective areas for producing value added products. 

It is a very happy Augury that the Government of India has accepted the requests of all 

these women and announced 50% subsidy for the SDM 50 Solar Drier being supplied by 

SEED and it is hoped that a large number of AIWC branches will take this offer and get 

benefited. SEED has always been very helpful to the NGOs and it is hoped that they will 

continue to help the needy women to enhance their income. 

26


Solar drying of fruits, vegetables, spices, medicinal plants and fish: 

Developments and Potentials 

B. K. Bala, Department of Farm Power and Machinery 

Bangladesh Agricultural University, Mymensingh-2202, Bangladesh 

e-mail: bkbalabau@yahoo.com 

Serm Janjai, Department of Physics, Silpakorn University, Nakhon Pathom Thailand, e-mail: 

serm@su.ac.th 

• Topic(s) addressed: Local solar food processing technologies (oral presentation) 


Drying is the oldest preservation technique of agricultural products and it is an energy 

intensive process. High prices and shortages of fossil fuels have increased the emphasis on 

using alternative renewable energy resources. Drying of agricultural products using 

renewable energy such as solar energy is environmental friendly and has less environmental 

impact. 

Sun drying is still widely used in many tropical and subtropical countries. Sun drying is the 

cheapest method, but the quality of the dried products is far below the international 

standards. Improvement of product quality and reduction of losses can only be achieved by 

the introduction of suitable drying technologies. However, increase of purchasing power of 

the farmers of the dryers and the reflection of the quality in the price of quality dried products 

are the important prerequisites for acceptance by the farmers and introduction of improved 

drying technologies. As long as there is no or only slight difference in the price for high and 

low quality products, the additional expenses for new preservation techniques will never be 

paid back and the new drying technologies will not be acceptable by the farmers. However, 

for adoption of the improved technology field level demonstration of the technology and 

advertisement of the quality dried products are essential. Micro-credit may also be needed 

and an extension model which is also an extension of the micro-credit approach of Grameen 

Bank may be adopted. Furthermore, for sustainability of the improved drying technology 

marketing channels must be established. 

Solar drying can be considered as an elaboration of sun drying and is an efficient system of 

utilizing solar energy. The tropics and subtropics have abundant solar radiation. Natural 

convection solar dryers do not require power from the electrical grid or fossil fuels. Hence the 

obvious option for drying would be the natural convection solar dryers. Many studies on 

natural convection solar drying of agricultural products have been reported. Several designs 

are available and these are (i) cabinet type solar drier suitable for drying fruits and 

vegetables, (ii) indirect natural convection solar drier for paddy drying and mixed mode AIT 

drier for drying paddy. These dryers have been widely tested in the tropical and subtropical 

countries. Considerable studies on simulation and optimization have also been reported. The 

success achieved by indirect natural convection solar dryers has been limited, the drying 

rates achieved to date not having been very satisfactory. Box type dryer is suitable for drying 

of 10 – 15 kg of fruits and vegetables. The mixed mode dryer and AIT drier are improvement 

over the indirect natural convection solar dryer. All of these types of dryers have been tested 

and attempts have been made to extend at the farm levels. But none of these dryers 

practically exist in the fields in the tropics and subtropics. However, Kenya black box dryer 

which is a mixed mode solar dryer is claimed to be appropriate for small scale drying. 

Furthermore, these dryers are not suitable for small scale industrial production of fruits, 

vegetables, spices, fish and medicinal and herbal plants. These prompted researchers to 

develop forced convection solar dryers. These dryers are (i) solar tunnel drier, (ii) indirect 

forced convection solar drier, (iii) Greenhouse type solar drier, (iv) Roof integrated solar drier 

and (v) Solar assisted dryer. Numerous tests in the different regions of the tropics and 

subtropics have shown that fruits, vegetables, cereals, grain, legumes, oil seeds, spices, fish 

and even meat can be dried properly in the solar tunnel dryer. 

27


The purpose of this paper is to present the developments and potentials of solar drying 

technologies for drying grains, fruits, vegetables, spices, medicinal plants, and fish in the 

tropics and subtropics and the performance of the solar driers for drying of fruits, vegetables, 

spices, medicinal plants and fish and also to present simulated performance of the solar 

tunnel dryer for drying of chilli and neural network prediction of the performance of the solar 

tunnel drier for drying of jackfruit and jackfruit leather, and address the applications of 

Computational Fluid Dynamics (CFD) in food industry. 

3. Summary 

This paper presents developments and potentials of solar drying technologies for drying 

of fruits, vegetables, spices, medicinal plants and fish. Previous efforts on solar drying of 

fruits, vegetables, spices, medicinal plants and fish are critically examined. Recent 

developments of solar dryers such as solar tunnel dryer, improved version of solar dryer, 

roof-integrated solar dryer and greenhouse type solar dryer for fruits, vegetables, spices, 

medicinal plants and fish are also critically examined in terms of drying performance and 

product quality, and economics in the rural areas of the tropics and subtropics. 

Experimental performances of different types of solar dryers such as solar tunnel dryer, 

improved version of solar tunnel dryer, roof-integrated solar dryer and greenhouse type 

solar dryers which have demonstrated their potentialities for drying fruits, vegetables, 

spices, medicinal plants and fish in the tropics and subtropics are addressed. 

Simulated performances of solar tunnel dryer, improved version of solar tunnel dryer and 

roof-integrated solar dryers were assessed for drying fruits, vegetables, spices, medicinal 

plants and fish. The agreement between the simulated and experimental results was very 

good. The simulation models developed can be used to provide design data and also for 

optimal design of the dryer components. 

A multilayer neural network approach was used to predict the performance of the solar 

tunnel drier. Using solar drying data of jackfruit and jackfruit leather, the model was 

trained using backpropagation algorithm. The prediction of the performance of the drier 

was found to be excellent after it was adequately trained and can be used to predict the 

potential of the drier for different locations and can also be used in a predictive optimal 

control algorithm. 

Computational Fluid Dynamics (CFD) as a tool for prediction of flow and temperature 

fields inside the solar collector and solar dryer is addressed and the applications of CFD 

in food industry are discussed. 

Finally, prospects of solar dryers for drying fruits, vegetables, spices, medicinal plants 

and fish in the tropics and subtropics are discussed. 

28


Scheffler Parabolic Dish from 7,2m2 to 50m2 at the Brahma 

Kumaris, Mt. Abu 

Golo Pilz, Advisor, Brahma Kumaris , Pandav Bhawan, Mount Abu 307 501 Rajasthan, India, 

mobile 09413384877, golobhai@gmx.net 

Examples of solar food projects : successes and hindrances, networking and cooperation, 

Solar food processing and back-up systems, how to ensure sustainable energy supply 

1. RENEWABLE ENERGY WITH A SPIRITUAL FOUNDATION 

Since more than15 years PRAJAPITA BRAHMA KUMARIS ISWHARIYA VIDYALAYA (BK) 

which has more than 7000 Meditation centers in India and more than 500 abroad is actively 

involved in the research and demonstration of alternative renewable energy concepts. 

The Brahma Kumaris is mainly administered by women and teaches spiritual and ethical 

values in India as well as in more than 100 other countries. The institution is a Non- 

Governmental Organization (NGO) of the United Nations, affiliated to the Department of 

Public Information (DPI). It has general consultative status on the roster of the UN Economic 

and Social Council and UNICEF. The organization has participated in several UN peace 

projects, as well as the Earth Summit in Rio, 1994 and Habitat 2 in Istanbul, 1996. The 

Brahma Kumaris received six UN Peace Messenger Awards. 

The Brahma Kumaris headquarters comprises three large complexes at Mt. Abu and Abu 

Road. Pandav Bhawan, the International Headquarters; the Academy for a Better World, 

Gyan Sarovar, near Mt. Abu; and Shantivan Complex at Abu Road. The institution can 

accommodate up to 20,000 people. 

Established in 1992, the Brahma Kumaris' Department of Renewable Energy works in 

tandem with the World Renewal Spiritual Trust, an affiliate of the University. After focussing 

almost exclusively on education in values and spirituality since its foundation in 1937, the 

University expanded its purview to include the field of renewable energy. This decision was 

taken in the context of worldwide environmental degeneration and the pressing need to meet 

the requirements for electricity and other power sources for its many residents and visitors. It 

became obvious to combine Spirituality and Values with development of solar energy and 

other alternative technologies. The fusion of both drives us towards a better future. 

Since then BK became one of the key developers in the world in solar institutional cooking 

systems. We also work in the area of solar photovoltaic Power stations with an installed 

capacity of more than 700 kw peak, spread throughout the Indian subcontinent. In addition 

various wind & solar photovoltaic hybrid systems have been tested. With the help of a solar 

Aditya shop the local residents are supplied with solar lanterns, photovoltaic home light 

systems and solar cooking boxes. 

Mt. Abu in Rajasthan, India, possesses favorable sources of potential renewable energy. At 

Mt. Abu's altitude of 1,200 meters there are almost continuously clear skies. The wind speed 

and the solar radiation in Mt. Abu are among the best in the state of Rajasthan. 

29


2. Summary 

A Department for Renewable Energy was established by BK in 1992, at the Gyan Sarovar 

Academy for a better World and a Solar Energy House was constructed. 

Since then, the solar radiation and wind speed have been continuously monitored on a 

computerized data logger 

In 1996, a solar steam cooking system for 1000 people was installed. The cooking system 

was sponsored by GTZ and designed by Wolfgang Scheffler / Brahma Kumaris/ Eco Centre, 

Valsad, and HTT, one of the leading German companies in heat transfer technology. The 

parabolic concentrators with a size of 7.2sq meter are made in India and have a total 

surface area of 190 sq meters. With an output of 650 kg steam per day, the cooker is a fine 

example of the successful use of solar thermal energy on large scale. 

In January 1998, a solar steam cooking system for a maximum of 35,000 meals per day was 

constructed in Shantivan Complex, Abu Road. This system consists of 84 newly developed 

concentrators of 9.5sq meter and generates the steam directly in the receivers. The system 

generates around 3500 Kg steam per day. The plant was successfully commissioned and 

tested and has been running excellently for the last nine years. A second steam cooking 

system for 600 people was set up in Yelapur (Hubli), and an additional system for 2000 

people was constructed at Om Shanti Retreat Centre near Delhi. 

In 2003, one more solar steam cooking system with financial assistance of MNRE with an 

increased dish size of 12.6 sq m and new improved layout to provide steam for the canteen, 

sterilizers and laundry was completed for the Global Hospital and Research Centre in Mt. 

Abu. 

A smaller system with 7 dishes and state of the art receiver/ Tracking / Steam tank design 

was completed in 2005 at the Headquarters of Brahma Kumaris in Mt. Abu. 

In 2006 with the help of Wolfgang Scheffler a new 16sq meter prototype dish was 

successfully designed and tested as an R& D together with the MNRE. Further solar steam 

systems with the state of the art 16 sq meter dishes are in planning. 

In 2008 Brahma Kumaris designed, build and tested together with Wolfgang Scheffler a 

new and innovative 50sq meter prototype dish for power generation and steam 

production. 

The solar steam cooking systems developed by the Brahma Kumaris have been recognized 

by the ministry of Non Conventional energy sources and are eligible for 50 % grant of the 

total costs. 

30


Our experience with Solar Concentrating Steam System in our Food 

Industry 

Ghanshyam Lukhi 

Tapi Food Products 

112, Sahyog chambers, Mini Bazar, Varachha Road, Surat-395006.India. 

email:tapifood@gmail.com 

India is blessed with abundant sunshine and Sun has special position and Status in our 

Society and is worshipped. 

We at Tapi Food Products decided to tap solar energy for our process Industry because we 

are convinced that use of solar energy is good for everyone in many ways. 

First it reduces energy cost for our food processing because after one time 

investment 

there is hardly any running cost 

Second our company gets green image 

Third it may help in marketing our products as environmentally manufactured product 

and 

Last but most important it serves the cause of environmental protection. 

In our presentation we will present our case study and share our experience 

with other participants 

We have a solar system with 10 scheffler dishes generating steam which is used 

for concentrating juice n in making of products like Fruit jams, Jellies, Papaya tutti 

fruity, Syrups, Squashes, Marmalades, etc. 

We have been fortunate to get government support in form of subsidy and also 

carbon credits to make project more feasible. 

We are the first in India to manufacture food products by solar steam. 

31


SOLAR DRYERS FOR HIGH VALUE AGRO PRODCUTS 

AT SPRERI 

T. V. Chavda* and Naveen Kumar 

Sardar Patel Renewable Energy Research Institute, P.B.No. 2, Vallabh Vidyanagar– 388 120 

(Gujarat), Tel : (02692) 231332, 235011, Fax : (02692) 237982 

*E mail: tilak_chavda@yahoo.co.in, info@spreri.org 

Topic addressed: Solar food processing and back-up systems 


Many agricultural, horticultural, chemical and pharmaceuticals products need drying to 

reduce their moisture content for various purposes like safe storage, easy handling, value 

addition, further processing and quality improvement. In order to achieve fast, reliable and 

hygienic drying, many in the organized sector employ mechanized dryers fueled through 

firewood, groundnut shells, saw dust, petroleum fuels like Low Density Oil (LDO) and diesel, 

Liquid Petroleum Gas (LPG) and electricity for drying the large quantities of low and high 

value products. The rise in cost of fuels and pollutants being added to the atmosphere, have 

resulted in a search of safer alternatives like solar drying. A solar dryer is an enclosed unit, to 

keep the product safe from damage, birds, insects and unexpected rainfall. The product is 

dried using solar thermal energy in a cleaner and healthier way. Solar dryers are found to be 

technically and economically feasible in many industrial and agricultural sectors. Roof space 

available in small-scale industries would normally permit installation of systems of one to two 

tones per day capacity. If a solar dryer were employed to replace an electrically operated 

dryer, the lifetime cost of solar dryer would only be a third of the electrical dryer at the 

present price of electricity. Similar analysis for diesel fuelled systems indicate that solar 

systems would cost only about half to that of diesel system. 

Solar dryers that have been developed at Sardar Patel Renewable Energy Research Institute 

(SPRERI) can be classified into direct and indirect systems. Direct dryers expose the 

products to be dried to direct sun light while the indirect systems protect the products from 

the exposure. Direct system, though are cheaper, but often lead to discoloration of the 

agro/chemical products resulting in poor quality of the final dried items. Thus, indirect type 

solar drying systems are highly suitable for industrial and commercial applications due to the 

good controls available, superior quality of the final dried products and scope of integrating 

with existing systems. Indirect type systems with thermal back-up are found to be the most 

adaptable and suitable for obtaining large quantities of high quality high value agro products. 

Mainly, all of the solar drying system consists of solar air heaters, drying chamber, blower, 

ducting, controls and thermal back up (optional). Solar air heaters are flat plate collectors/ 

packed bed collectors or unglazed collectors that can be installed on the ground, roof etc. In 

order to obtain maximum heat from solar energy, the solar air heaters need to be installed 

facing true south at a suitable tilt with respect to horizontal. Depending on the temperature of 

hot air, air flow rate and types of product to be dried, collectors are installed in series and 

parallel modes. It is essential that no shadow from any building or trees fall on the solar 

collectors throughout the year. 

2. Summary 

SPRERI concentrated its work on indirect type forced circulation solar drying system and 

developed its first model with electrical back-up in its campus in the year 1995. This system 

was mainly used to generate basic data on solar drying of high value products including 

onion, Amla, potato, chilly, various other fruits, vegetables, ayurvedic and herbal products. 

Quality evaluations showed that the indirect solar dried products were far superior to the 

open sun dried ones in terms of good colour, texture and hygiene. The details of some of the 

32


different models of indirect type solar dryers designed and installed by the institute in the field 

with financial assistance from different agencies like All India Coordinated Research Project 

on Renewable Sources of Energy of Indian Council of Agricultural Research, New Delhi 

(AICRP-ICAR on RES) and Ministry of New and Renewable Energy (MNRE) are given 

below. 

1. Forced circulation glazed solar dryer: This dryer is suitable for drying high value agro 

products like ginger, tomato, amla etc. This is the most efficient design, though the cost of 

installation is also the highest. These types of dryers have been installed at M/s Shivam 

solar dryer, Ahmedabad (Fig.1 & 2), SPRERI, Vallabh Vidyanagar (Fig.3), M/s Handmade 

Paper Institute, Pune and M/s Swambe Chemicals, Vadodara. All the systems are 

working successfully. A temperature gain of 25°C could be easily achieved and the 

payback period for this type of system is around 3½ to 4½ years. 

Fig. 1 & 2 : Glazed solar air heater with LPG back up 

installed at M/s Shivam solar dryer 

Fig.3: Glazed solar air heater with 

electrical back up at SPRERI 

2. Roof integrated unglazed solar dryer: This type 

of dryer is suitable for low temperature drying 

products like mushroom and leafy vegetables. 

Though the efficiency is lower but the cost of 

fabrication and installation is also lower and pay 

back period is also less than 2 years. This type of 

dryer has been installed at M/s Mashika Agritech, 

Vadodara as shown in Fig.4 and working 

satisfactorily. Total temperature gain of 10 to 15°C 

could be achieved. 

Fig.4: Unglazed solar air heaters 

with electrical back up at M/s 

Mashika Agritech, Vadodara 

3. Roof integrated glazed-unglazed solar dryer: This type of system is installed at M/s 

Gujarat State Forest Development Corporation, Vadodara (Fig.5) for drying ayurvedic 

churnas and other herbal products. Its efficiency and pricing comes in the middle of 

above two types of the systems. The payback period for the system is around 3 years. 

Fig.5: Glazed & unglazed solar air heaters with electrical back up at GSFDC, Vadodara 

33


Solar Food Processing 

Its Economic and Ecologic Value for India* 

C.L.Gupta # 

Preamble 

Processing of food, without losing its aroma, colour, texture or structure has 

always been of prime importance for food and more recently for herbal medicines 

and cosmetics. After all, Europe was initially attracted to India because of its 

spices and silks. India has woken to its potential rather late but PIO abroad are 

doing roaring business with nuts, herbs, spices and flowers and they all want 

solarization of their farms and processes. If we couple further the products to 

organic cultivation, solar processing and international standard biodegradable 

packaging, one is in premium products bracket for exports. International 

protocols for certification of such products are already operational. At home, the 

ecological value of solar processing in terms of empowerment through income 

generating livelihoods enterprises for equity and ecologic nature of renewable 

resources for energy quality and security with no carbon penalty, are of 

tremendous importance nationally. 

Work done so far 

India has been a pioneer in these efforts, but in a rather low key as in other 

areas. To my knowledge, the first such plant for drying of fruits was 

commissioned by Palni Hill Conservation Council at Kodaikanal [1] in early 

eighties. Gupta did the first roof top solar tea drying at Munnar[2]. Later 

Palaniappan took it up in a more sustained manner and developed solar drying 

industry for cardamom, tea, coffee, pulses, spices and fish in Tamilnadu and later 

in Ladakh, Phillipines and UAE [3]. The earlier work on drying of cereals such as 

paddy was economically not viable for the plants were operated for less than 

three weeks in an year because of cropping patterns 

*International Conference on Solar Food Processing, Barli Development 

Institute for Rural Women, M.P. India, 14-16 January, 2009. 

# Professor, Applied Sciences, Sri Aurobindo International Centre of 

Education, Sri Aurobindo Ashram, Puducherry 605002. India. 

Email: solagni@auroville.org.in 

34


Work ahead 

Multi product dryers are difficult to design but not impossible. Portable dryers, 

developed earlier for fisheries in Bay of Bengal Program of UNICEF, did not 

catch up but need reviving, evaluation and quality enhancement. Quality 

drying of herbs and nuts with incorporation of solar operated heat pumps [4] 

are yet to pick up in India and obviously are the next stage. Indian heat 

pumps are now available from 5 kW to 100 kW range and if the whole supply 

chain of foods so dried is organized properly, we will have a really good 

export line in tune with times[5]. 

Intellectual issues in food processing and drying systems are really 

challenging in terms of theory, systems and at products level and should be 

developed more vigorously than hitherto. It should be a mission mode effort 

like gasifiers, which incidentally could serve as the other system to solar in 

hybrid mode and also solve the problem of disposal/pollution caused by food 

processing residues as they could serve as feed stock, as briquettes or in 

loose form, for gasifiers. These areas need to be pursued vigorously. 

References 

1. Jayakaran. PHCC Vegetables and fruits dryers at Batlagundu, India 

(Private Communication. 1983) 

2. Gupta,C.L. Solar tea drying at Tata Tea, Valparai, Western 

Ghats,India in association with M/S Best and Crompton 

Ltd.(Private Communication.1982) 

3.Palaniappan, Role of solar hot air system for food processing in 

C. and `Renewable Energy Technologies application to industries 

Subramanian, and agriculture’ (Ed.Palaniappan,C.etal) Narosa, New 

S.V. Delhi, India pp. 410 -21 (2001) 

4. Britnell,Peter Development and application of Heat Pump Driers,Deptt. 

Sigley,Eroll of Primary Industries (Agribusiness),Queensland, 

(Coordinators) Australia (1994) 

5. Milind,R. Use of heat pumps for drying (Private Communication 

2007) Heat Pump Lab. IIT Bombay, Mumbai 

35


Design of Solar Dryer with Turboventilator and fireplace 

Prof. Ajay Chandak. Dr. S.K. Somani. 

Author has been using solar dryers for food processing, especially making Amla 

candy, since last 5 years. First drier is an innovative design with combined 

draught, natural and induced with fan. This dryer works well when fan induces 

draught. However when there is no power, the dryer works with natural draught 

but system under performs as the airflow is drastically reduced. In rural areas in 

Maharashtra Power cuts were increased to almost 14 hrs a day and practically 

no power is available to run fan during daytime when Sun is available. To counter 

this problem author has come up with a new design of solar dryer, which uses 

turboventilator for creating draught. Turboventilator runs on external wind and 

creates necessary draught and maintains good airflow through the solar dryer 

giving excellent performance. As the turboventilator works on outside wind only, 

no power is required and unit is truly a renewable energy gadget. The unit is also 

provided with a fireplace and bypass chimney. This facility permits the use of the 

dryer in night hours, cloudy days and also to accelerate the drying process when 

the Sun is available, by using some fuel like waste biomass. Turboventilator was 

preferred over Solar PV operated fan for the reasons of cost and possibility of 

operation at night or in cloudy period. The paper discusses the results on 

conventional and new solar dryer. Both the dryers are of 7 sqm area each. 

Results of new solar dryers are very encouraging. 

36


Back-up for Solar Driers with hygroscopic Calcium Cloride 

Wolfgang Scheffler, Solare Bruecke, Graf von Werdenbergstr. 6. D-89344 Aislingen, 

wolfgang@solare-bruecke.org, 0049-9075-701338 

Heike Hoedt, Solare Bruecke, Graf von Werdenbergstr. 6. D-89344 Aislingen, 

HeikeHoedt@solare-bruecke.org, 0049-9075-701338 

Topic(s) addressed: Solar food processing and back-up systems, how to 

ensure sustainable energy supply 


Solar driers often need a back-up for periods without sunshine. A simple system is 

presented, using liquid and solid CaCl2*(H2O)x as a recyclable absorbent for excess 

humidity. The authors used this system successfully to dry plums in a 2m x 1m solar tunnel 

drier in Germany under changing weather conditions. 

2. Summary 

When the sunshine fails during the drying process in a solar tunnel drier, the fruits or 

vegetables can get spoiled. In Germany, on several occasions we used food grade 

hygroscopic Calcium Cloride salt in combination with an internal fan for closed loop 

air circulation to keep the air in the drier dry on rainy or overcast days. That way the 

the drying process was continued and spoiling was prevented. 

The dry salt is placed on stainless steel trays in the empty section of the tunnel drier together 

with an electric fan to ensure a continuous movement of the internal air. Then all openings of 

the drier are closed. The solid CaCl2 absorbs the humidity and turns liquid. The liquid is later 

recycled by boiling the water off on a 2m² Scheffler reflector. 

37


Parabolic Solar Concentrators for Cooking and Food Processing 

Deepak Gadhia Gadhia Solar Energy Systems Pvt. Ltd. 

Plot No 86, Old GIDC Gundlav, , Valsad,396035, Gujarat el. Tel. 0091-9825117353, 

Fax. 0091-2632-236703,: 

Email: gadhiasolarahoo.co.in 

Webpage: www.gadhiasolarenergy.com 

Topic: Solar food processing and back-up systems, how to ensure sustainable 

energy supply 

1. Introduction : 

In our presentation, we would like to share our 20 years experience in development of 

Solar Concentrators Technology in India, on our return from Germany in 1985. 

We availed of technology from Austria, Germany and Switzerland and with the help and 

collaboration of the inventors, developed upon it. based on inputs and feedback from 

users the technology was further improved upon to make it user friendly. 

2. Summary : 

Over the years we have indigenised and commercialised the technology. 

To date, we have manufactured, supplied and installed solar cooking systems of various 

sizes, ranging from domestic- to community- to institutional-cooking systems, including 

the World’s largest solar steam cooking system at Tirupati Temple and the World’s 

highest solar steam cooking at Leh, Ladakh for the Indian Army. 

Solar concentrators can also be used for various other applications like 

• Solar Food Processing for value addition of agricultural produce 

• Solar Drying of agricultural produce. 

All these will help farming communities and empower them, after all 70% of India still 

lives in villages. 

Solar concentrators reduce carbon dioxide emissions substantially and so qualify for 

CDM. 

Kyoto Protocol Treaty and CDM (Clean Development Mechanism) can be tapped to 

finance such “Smoke-free Villages” projects, making it a Win-Win Situation for both 

developed and developing countries and Planet Earth Our Only HOME. 

Concrete examples will be given using a Power Point Presentation. 

38


Development and Application of Solar Cooker in China 

Chen Xiaofu & Han Tingcun 

China Association of Rural Energy Industry 

chxiaofu@126.com 

w13643@yahoo.com 

Abstract 

Striking progress and significant achievement has been made in Chinese Solar 

Cooker (SC) industry, especially in designing theory, material technology, 

technical standard and industrial production, dissemination and sales service 

after more than 30 years’ research and promotion. During this period it has 

experienced the change from independent research to national cooperation 

and the systematic study, from laboratory experiment to industrial production, 

and from governmental support to semi-commercialization. Currently, with a 

total number of more than one million sets, China has been the No. 1 in 

promoting SCs in the world. And the following will give the general review over 

the past 30 years. 

39


Design of multistage evaporators for integrating with Scheffler 

Solar concentrators for food processing applications 

Prof. Ajay Chandak. Dr. S.K. Somani 

Author designed and experimented with multistage evaporation system for 

production of distilled water. Two Scheffler concentrators of 16 sqm each were 

used for generating steam in the first stage at 8 bar pressure and the pressure is 

gradually brought down to 1 bar, in four stage distillation unit. Total yield obtained 

in the project was 2.4 times that of single stage distillation. Temperature drop in 

every subsequent stage was designed to 25 degree centigrade. Heat of 

condensation in the last stage was dissipated in a solar dryer to enhance its 

performance. In further testing this heat of condensation in the last stage and 

also sensible heat of the condensate in all the stages was used for preheating of 

water in the next batch. The system has great potential in food processing 

industry for applications of juice thickening, sauces, jams, salt concentrating 

systems and distilled water applications. Results of the project are very 

encouraging. 

40


SOLAR FOOD PROCESSING- AUTHORS EXPERIENCE WITH 

COOKING AND DRYING IN COSTA RICA 

Shyam S. Nandwani 

Laboratorio de Energía Solar, Departamento de Física, 

Universidad Nacional, Heredia, Costa Rica. 

E mail: snandwan@una.ac.cr, snandwan@yahoo.com 

Solar food processing is the integration of various processes with the basic materials to get the 

required product of given quality at the right time and using the minimum conventional fuel. Use of 

solar energy can definitely help in this aspect. Since 1977, author is doing research on different 

models of solar water heaters, stills, dryers and mainly cookers – hot box, hybrid sol- electric 

cookers, multiple uses solar cookers like cooker cum water heater/pasteurizer, cooker cum dryer 

etc. In addition to publish results in technical journals, disseminating the experience through 

lectures, TV, Radio, newspapers, workshops, seminars in Costa Rica and 35 other countries, 

author and his family is also using at home most of these devices when ever the climate permits. 

Author has recently designed one hybrid food processor (multipurpose device) and studied 

various technical and practical aspects. It has been used for cooking, heating/pasteurizing water 

(to inactivate microbes) and distillation of small quantity of water (to remove different minerals) 

and drying domestic products (fruits, vegetables and condiments / herbs). 

The variables like temperature, weight and water contents of various edible products for drying, 

instantaneous, and more important integrated solar radiation, and electrical energy used are 

measured. In this short presentation, part of the experience related to food processing – some 

cookers and dryers and their uses for cooking, drying, water heating and pasteurization will be 

informed. 

With these types of hybrid devices, the guarantee of your meal and drying of products at the right 

time and with the reduced consumption of conventional fuel can justify the extra investment. 

For more than four years of use, author has found hybrid system as a useful device, mainly from 

convenience, fuel saving, economic and also from ecological point of view. It can be used at any 

time and for different uses but with the reduced consumption of conventional fuel. 

Topics addressed: Local Solar Food Processing Technology, Solar Food Processing and back 

up systems 

Conventional Solar Cooker (1980) and Hybrid Solar-Electric Food processor (2003) designed, 

studied and used by author and family. 

41


Drying Studies on Single Layer Thompson Seedless Grapes 

R.L.Sawhney*, D.R.Pangvahane and P.N.Sarasvadi 

School of Energy and Environmental Studies, Faculty of Engineering Sciences, 

Devi Ahilya University, Khandwa Road, Takshila Campus, Indore, Mahya 

Pradesh, India.452011 

*sawhneyrl@gmail.com Tel.: +91-0731-2460309: Telefax: +91-0731-2467378, 

2462366 


For determination of drying Kinetics of Thompson seedless grapes a suitable 

experimental unit for online measurement was designed and fabricated. The drying 

characteristics of suitable oil emulsion pretreated grapes were measured using 

ambient air under controlled air temperatures (50 to 80 degree centigrade), air 

velocity (0.25 to !.00 m/s) and relative humidity (30 to 80 %) conditions. 

2. Summary 

Out of the three models considered (Page’s, Single term and Two term exponential) 

Page's model was found to be the most appropriate for describing the drying behavior of 

the grapes. The dependence of drying constant K of the Pages model on the above 

mentioned process variables was analyzed using Arrhenius and Power Equations. It is 

found that the Arrhenius Equation gives better values of K than Power Equation. 

It is also found that the dependence of another drying constant N of the Page's equation 

on the process variables can not be described in terms of Arrhenius or Power equation. 

42


Performance of PV Winnower cum Dryer for Processing of 

Agricultural Products 

P.C. Pande 

Central Arid Zone Research Institute 

Jodhpur, 342003, India 

Email: pcpande@cazri.res.in 

Topic(s) addressed: Solar food processing and back up systems, how to ensure 


Introduction 

The solar PV winnower- cum- dryer is unique system, which was designed and 

developed to provide a convenient device for winnowing and cleaning threshed 

agricultural produce and also for dehydrating fruit and vegetables with forced circulation 

of air, the two post harvest processing activities associated with agriculture production. 

The composite photovoltaic-thermal unit comprises a PV module- mirror booster 

assembly, a compatible winnower, a pre air heating tunnel, an especially designed solar 

drying cabinet for utilising solar energy effectively and having interfacing arrangements 

to use the fan of the winnower for enhanced air circulation while dehydrating the 

produce. 

Summary 

Performance of this unique device the PV winnower cum dryer has been carried out both 

as a winnower and as a dryer. As winnower, 950 kg cluster bean could be winnowed by 

operating it for 6 hours each for 4 days, 360 kg pearl millet with in 8 hours, 460 kg 

mustard in 9 hours indicating that as a winnower on an average 35-50 kg cleaned 

grains/seeds could be obtained in one hour with this device. As a dryer, experiments for 

drying spinach, fenugreek, mint (poodina) and coriander leaves (10 kg) were carried out 

successfully for dehydrating the produce from 85-87% moisture content to 5% in 24-28 

hour compared to 50-70 hours in open sun. The enhancement in the fan speed with 

more irradiance regulated the temperature inside the bin while the pre air heating in the 

extended tunnel reduced the thermal gradient inside the drying cabinet and thus 

provided excellent quality of the dried material with retention of aroma and green colour. 

Experiments were conducted for dehydrating chillies and other different fruits also. 

Kachara (local fruit like that of cucumber) slices could be dehydrated from 94 % moisture 

content to 5 % with in 70 hours, 46 kg ber were dehydrated in overcast weather 

conditions from 75 % moisture content to 15 % in 288 hours reducing the drying time to 

more than one third compared to open sun. The overall drying efficiency varied from 15 

% to 22 % for different products. 

The system is provided with additional features to use it for illumination also and thus 

making it an extremely useful device for processing different agricultural produce and 

utilising the generated PV electricity for one or other purpose round the year. The 

dehydrated product is of high quality and therefore the farmers can accrue higher 

benefits. 

43


PROCESSING OF AGRICULTURAL PRODUCTS IN SOLAR COOKER 

FOR INCOME GENERATION 

N. M. Nahar, P. Sharma and G. R. Chowdhary 

Central Arid Zone Research Institute, Jodhpur-342003, India 

Topic addressed: Solar food processing and back-up systems, how to ensure 


Introduction 

With fast growing population and rapid growth of industries, the consumption of energy is 

increasing enormously. The requirement of energy for the next century is 100 Q (1 Q = 2.98 x 

10 14 kW). The reserve of fossil fuels of the entire world including known and unknown sources 

is not more than 50 Q. Therefore, at the present rate of energy consumption the world energy 

resources will be exhausted in 50 to 100 years. Therefore, there is need to harness solar 

energy and other alternative energy sources. 

The solar radiation outside the earth’s atmosphere remains practically constant and is 1.353 

KWh/m 2 . The eccentricity of the earth’s orbit results in variation of about + 3 %. The radiation 

received at the earth’s surface is considerably reduced below the extraterrestrial value due to 

reflection, absorption and scattering of radiation in the earth’s atmosphere, therefore, the total 

solar radiation received at the earth’s surface consists of direct and diffuse radiation. India 

occupies better position regarding solar energy potential. In the month of December, solar 

radiation increases from 2.6 KWh/m 2 day at Gulmarg to 3.7 KWh/m 2 day at New Delhi, 4.1 

KWh/m 2 day at Calcutta, 4.5 KWh/m 2 day at Jodhpur and 4.3 KWh/m 2 day at Kodaikanal. During 

the period November to February i.e. winter season, most of the Indian stations receive 4.0 to 

6.3 KWh/m 2 . During summer season i.e. March to May, this value ranges from 5.0 to 7.4 

KWh/m 2 . The arid and semi-arid part of the country receive much more radiation as compared 

to rest of the country with the mean annual daily solar radiation received at Jodhpur i.e. 6.0 

KWh/m 2 . 

Summary 

Solar cookers are generally used for cooking of food for domestic as well as community places. 

But solar cooker can also be used in agro based industries e.g. processing of Indian goose 

berry ( Aanwala ), jujube ( ber ), for making jam & jelly, chutney and preparation of rose syrups 

& gulkand from rose and sugar. These materials are prepared in agro based industries by 

using conventional fuels. 

Rose water has been prepared. Rose petals 100 gm per litre in water was boiled in the solar 

cooker for two hours. After boiling rose water was collected and 500 gm sugar per litre was 

mixed and again put into the cooker for boiling. The solution is rose syrup and remaining 

material was mixed with sugar and again put into the cooker and it became gulkand. Similarly 

Aanwala chutney was also prepared. Crushed green Aanwala mixed with sugar and put into the 

cooker. It was ready within three hours. Different solar cookers viz. hot box solar cooker, large 

size solar cooker, community solar cooker can be used for processing 2 kg, 10 kg and 40 kg 

product per day respectively depending upon requirement. Detailed design aspects and 

procedure of processing will be reported along with income one can generate from solar 

cooker. 

44


Solar Food Processing Network 2009 

Rolf Behringer, International Solar Energy Society, Wiesentalstrasse 50, 79115 Freiburg, 

sun@robeh.de, tel:+49-761-1373680 / fax: +49-761-4808412 

Topic(s) addressed: International marketing, Networking 


The International Solar Energy Society (ISES) has launched the Solar Food Initiative to 

address issues relevant to the wider use of solar food processing technologies, the 

production of quality products, as well as marketing and public acceptance of solar food 

products. The actual status of the Solar Food Processing Network will be presented and an 

outlook for future goals and activities will be given. 

2. Summary 

Solar food processing is an innovative and multi-faceted technique capable of addressing 

various problems faced by people in many parts of the world. The implementation of 

technologies for food processing and conservation through solar energy can help to reduce 

poverty, improve health conditions, create sustainable local economic opportunities, and 

more importantly, limit environmental damage by promoting the use of clean / renewable 

energy sources. 

Together with new and existing partners from different countries (experts, politicians, 

farmers, development NGOs and women’s organisations), ISES intends to apply, test, 

evaluate and improve existing solar food technologies, to obtain high quality standards in 

sustainable food production and to promote this economical and ecologically viable 

technology. 

Many regions in the global South have excellent solar radiation potential, but often people 

lack awareness on how to harness this energy. The introduction of appropriate solar 

technologies provides access to ‘free’ energy and opens a wide range of sustainable energy 

consuming activities. The main target group is people in rural areas and townships, who 

often do not have access to grid-electricity. Communities that generate an excess supply of 

fruits and vegetables are especially interesting target areas, because they have the 

motivation to find practical means to conserve the fruits of their labour. 

The project aims to extend the use of, and to develop efficient methods of, solar food 

processing for the following activities: 

- Conservation of fruits and vegetables 

- Drying crops 

- Roasting different kind of nuts 

- Pasteurising juice, fruits and vegetables 

- Baking bread and cake. 

45


Global Network for Solar Food Devices: Future Priorities 

Bev Blum, Solar Cookers International Association 

4271 Round Valley Circle 

Stockton, CA 95207 USA 

Association@solarcookers.org or blumbev@aol.com 

Tel. +209-477-5970 

Topic addressed: Examples of solar food projects: networking 


In 2006 an international network, Solar Cookers International Association (SCIA), was 

formed by participants at the International Conference on Solar Cookers and Food 

Processing in Granada Spain, and Solar Cookers International (SCI) agreed to be its initial 

legal umbrella. SCIA membership has grown to 95 organizations and 150+ individuals. SCIA 

has collectively issued statements on carbon credits and solar cookers’ relevance to indoor 

air hazards, organized meetings for SCI’s U.N. Representatives with other key advocacy 

activists through SCIA’s Advocacy Task Force and created an interactive web site featuring 

all organizational and individual members which each can edit and expand. SCIA is 

outgrowing and being nudged out of its original nest and could grow many different ways. 

2. Summary 

These are exciting times. The past two decades have seen at least ten-fold increases in the 

spread of solar devices for household food and water processing. Opportunities are greater 

than ever. Promoters of water and food-related solar technologies are diverse in size and types 

of devices, but are stronger and experienced and all share a common passion to spread these 

technologies for health, economic and environmental benefits. 

Most promoters are middle class groups, educational institutions and governments sharing 

useful solar technologies with those suffering most from fuel shortages and most vulnerable to 

health and economic risks of current options. Spread of water and food-related solar 

technologies require both commercial and humanitarian efforts. Both require larger-scale 

production and effective, segmented marketing. We wish to re-examine what can be 

accomplished better collectively than by individual, isolated activities. 

I propose a brief presentation followed by discussion on these questions: 

1. How can this network most effectively strengthen both commercial and humanitarian 

strategies? 

2. What other networks and organizations might be our best allies? 

This conference is a timely opportunity to gather valuable input from both members and nonmembers 

on the future priorities and structure for this young network. 

Key-words: networks, collaborative advocacy, marketing, capacity-building, 

Preference for presentation: Brief presentation, mostly discussion 

46


Perspectives of solar food processing in India 

C.Palaniappan 

Planters Energy Network – PEN 

# 5, Power House Street, 

N.R.T.Nagar, 

Theni – 625 531 

Tamilnadu, India. 

Ph: +91 – 4546 – 255272 

Telefax: +91 – 4546 – 255271 

E.Mail: info@pen.net.in, pen01@sify.com, 

Web: www.pen.net.in 

1. Abstract 

One of the options to tackle food security and undernourishment amidst increased 

population in third world countries could be through solar drying of food products. It also adds 

up to the employment generation of large rural youth in these countries in addition to reduction 

of green house gases emanating from large quantity of fossil fuels, used in agro processing 

and other processing industries. Planters Energy Network(PEN) , a NGO has introduced roof 

mounted solar hot air technology, either as preheating or full energy units depending on the 

temperature requirement, for processing large quantities of food products. This article describes 

the technology adopted and its applications in the processing of various food products like tea, 

spices, fish, fruits & vegetables, pulses & grains, salt, etc. Sustainability of these units are 

proven as 15 years old units are functioning still. Apart from larger solar air heating units in a 

hybrid mode with fossil fuel, PEN has demonstrated smaller flat plate collector coupled with 

SPV operated driers successfully for drying fruits in Ladakh and fish in coastal regions of India. 

Concessions and incentives from Govt.of India make the solar units to have a low pay back 

period and so it has a greater potentials in the country. 

47


Title: Indian Case Study of Bundling of Solar Steam Cooking 

projects to sell Gold standards Certified Emission Reduction 

(CER) and Voluntary Emission Reductions (VER) 

1 Abstract : 

Deepak Gadhia 

Gadhia Solar Energy Systems Pvt. Ltd. 

Plot No. 86, Old GIDC Gundlav 

Valsad 396035, Gujarat, India 

Email: gadhiasolar@yahoo.co.in 

Experience of Bundling of Steam Cooking Project for Sale of CERs and VERs is shared. 

2 Background : 

Germany had hosted a global meet called Renewable 2004 in june in Bonn 2004. 

Around 3000 people were to participate and German Ministry of Environment and 

Nuclear Safety decided to make this Conference Carbon Neutral They started looking 

project from which they could buy Gold Standard CERs. The gave this task to its 

agency GTZ (Gesselschaft fuer Technische Zusamenarbeit= German Association of 

Technical Co-operation). The difference normal CERs and Gold Standard CERs is that 

the CERs arising of Sustainable project and which meet the stringent norms set by 

NGOs are called Gold standard CERs and they fetch better price than CERs. Mr. 

Christof Sutter of Factor is a friend of ours and has been associated with us right from 

beginning when we started our work on Solar Concentrators. At that time he visited India 

as Student Volunteer and was accompanying Mr. Wolfgang Scheffler. Later he finished 

his studies at ETH Zuerich and also did PhD there and joined Factor. In between he has 

earned reputation in field of CDM and is known as Indian Expert too. 

When he learnt that GTZ was looking for Gold standard CERs to make the meet Climate 

Neutral he approached us to ask if we would be interested. In past too we had done a 

project with along with him and Factor prepared PDD for a Bagasse based Cogeneration 

Power Project for a company that was planning to put up the same in a 

Sugar Industry Power Generation. At that time it was for Dutch Agency which had 

brought out tender to identify projects for CDM. 

Thus when Christof Sutter asked us we readily agreed to join hands with Factor and 

with their co-operation and inputs we prepared PIN and submitted same to Factor who 

submitted it to GTZ. GTZ liked the project and gave us go ahead. 

48


New energy meter for concentrating solar cookers to monitor 

CO2 savings and acceptance 

Christoph Müller, hc-tronic, Coronel Arias 1091, 4600 San Salvador de Jujuy, 

Argentina 

Tel: 0054/ (9) 388 4337154, Email: chris@hc-tronic.de 

Barbara Holzer, Fundacion EcoAndina 

Alexandros Cotanidis, Enveco GmbH 

Solar food: quality measures and indicators 

Abstract 

A new measurement device was developed, which allows measuring and logging the 

energy used in concentrating solar cookers. For this purpose the direct portion of the 

insolation received by the aperture area of the cooker is measured in units of kWh 

and stored every 30 seconds in a non volatile flash memory. The energy meter is 

fixed to the concentrating cooker normal to the aperture area. The optics of the 

energy meter is adapted in such a form, that the acceptance angle of the cooker is 

taken in account. Taking into account optical efficiency and aperture area, this allows 

for the first time quantifying at a good degree the CO2 savings and acceptance of 

solar cookers at relatively low costs. A data read out is required only one time per 

year. In CDM projects this measurement method allows an exact payoff to the solar 

cooker, corresponding to his real CO2 savings. 

Financed by a SEPS Project by the Wuppertal Institute, a first field test was started in 

2007 with 50 energy meters installed in the Argentine Altiplano by the Fundation 

EcoAndina. The CO2 savings of all users are summed up and the total amount of 

CO2 reduction is offered at the global certificate market. As high standards are kept 

regarding sustainable development, the certificates can be sold at the price of gold 

standard. The first results have shown that solar cookers in real life can save up to 3 

kWh/m² every day. In regions with little income, this mechanism can create an 

additional value of about 20 Euros per year and cooker, helping in financing the 

cooker over years and so helping in diffusion. 

49

Abstracts Oral Presentations - Solar Food Processing Network

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