Category Archives: EuroSun2008-9

STO implementation main problems

As can be seen in the RCCTE FAQs [19], the main questions are of two different types. One type is related with basic questions denoting the lack of knowledge of some stakeholders (“what is a solar thermal collector?”, and so on). Other, are related with requirements which need clarification or have not good criteria.

One example of those that are not good criteria is the rule of 1 m2 of solar thermal collector per conventional occupant, without any reference to the thermal performance of the product.. The problem is that a solar collector with both lower performance and lower cost is enough to satisfy the requirement, but the production cost of the sanitary hot water it is not always lower. The rule was also disturbing the market because the unique imposition of the collector area, was giving advantage to the lower performant and potentially lower cost products.

To overcome this problem, it is presently allowed that a lower value of collector area (in comparison to “1m2 per person” rule) can be accepted if the designer shows that an alternative solution collects yearly an equivalent energy of that of a standard solar thermal collector, which was defined with the following characteristics:

I) optical performance = 69%;

II) thermal losses coefficients a1 = 7.500 W/(m2.K), and a2 = 0.014 W/(m2.K2);

III) incidence angle modifier at 50° = 0.87;

IV) apperture area = 1.0 m2. —

The definition of the previous standard collector also permits to quantify the energy for sanitary purposes captured by solar thermal collectors, that can be substituted in the annual base, by other renewable sources and equipment (PV, wind, geothermal), even for other purposes.

Another example of a requirement which needed clarification is “what is a significant obstruction?”: Quantification of this requirement was agreed recently. First, it must be considered significant obstruction, a permanent obstacle between the solar thermal collector field and the Sun, which originate shadow for both a certain collector area an a certain time, to be evaluate under the following step by step methodology ([19] FAQ M.15):

i) evaluate the solar thermal system contribution for heating of sanitary hot water with SolTerm, using an obstruction with an angle of 20° to the horizon (situation correspondent to that of a total solar exposition in a period between 2 hours after sunrise and 2 hours before sunset), without the introduction of any other obstructions;

ii) maintaining the referred obstruction angle of 20°, add the obstruction to be studied “as significant”, and evaluate the solar thermal system contribution for heating of sanitary hot water with SolTerm;

iii) if the ratio of the two values of the solar thermal system contribution for heating of sanitary hot water obtained with obstruction and without obstruction is less than 0.7, the obstruction is considered “significant”.

Concerning the general problem of the lack of adequate knowledge by the stakeholders, it must be said that the problem is being studied within the framework of an European project [20], where INETI participates. Some points already identified are:

■ Information on Certification schemes (also of Solar Keymark) and on the tests performed and their interpretation among manufacturers and installers of Solar Thermal Collectors and Systems, although the Certification based on European Standards is already implemented and several products are already being certified;

■ Development of good practice manuals, for design and installation of solar thermal systems as well as for maintenance of both medium and large solar thermal installations, is needed;

■ Preparation of updated materials for courses specifically dedicated to i) maintenance of installations, ii) teachers of secondary schools (for children from the ages of 11 to 18), and

iii) consumers, addressing the selection of best solution.

■ Introduction of modifications in the curricula of architecture courses, covering in large scale the general bioclimatic aspects of construction, as well as, specific aspects related to solar thermal performance and its relation to thermal performance of buildings.


J. Heras*, A. Bosqued, R. Enriquez, J. A. Ferrer, J. Guzman, M. J. Jimenez, C. San Juan,

S. Soutullo, R. Bosqued and M. R. Heras.

Energy Efficiency of Building R&D Unit — CIEMAT.

Avda. Complutense, 22. 28040 Madrid (Spain)

Tl: 34-91-3466053, Fax: 34-91-3466037; e-mail:jesus. heras@ciemat. es


Between 2005 until 2010 the Spanish Minister of Innovation and Science (MICINN) is promoting a Singular Strategic Project called Bioclimatic Architecture and Solar Cooling, PSE — ARFRISOL (ARquitectura bioclimatica y FRIo SOLar, in Spanish), which plans to save up to 60% of the energy demand of an office building by means of passive techniques of construction. Reduce the conventional energy consumption to only the 10-20% of the usual consumption with active and passives solar techicals: solar thermal collectors and photovoltaic panels. Five office buildings are to be analized from energetic point of view: new buildings (four) and rehabilitated (one) in different climatic zones of Spain, thus the solutions for every building will be different, depending on the each climates.


All the components of the bioclimatic buildings and the technology for the active solar systems will be manufactured and optimised in Spain. Ventilated facades, solar chimneys, wide roofs and absorption pumps for solar collectors are some of the strategies to develop, depending on the climate. Almeria has the first building constructed: CIESOL (Centre of Research about solar application technologies), where the objective is to reduce the heat in summer with solar cooling. PSE-ARFRISOL has two edifications recently inaugurated: PSA (“Plataforma Solar de Almeria), and the ED-70 of CIEMAT in Madrid. The first stage of energetic strategies are concluded to confront a desert climate from Tabernas desert of Almeria and continental climate of Madrid.

ARFRISOL has another building in Spanish north geographical zone “Principado de Asturias” with an oceanic climate, at the Barredo Foundation, and, finally, in Soria, where a building of the CEDER will be rehabilitated in a extreme continental climate. After four years of investigation, the project will provide useful quantitative information about saving energy and passive and active solar energy use in buildings.


Finally, ARFRISOL will be pretended to influent in the society to change the mentality about energy consumption in the Spanish edifications and probe that it is possible to save 80 percent of conventional energy in office buildings with the incorporation of solar energy aplications (passive and active). With this objective the Ninth Subprojects has been planed to spread this idea between Spanish users.

Conference Topic: Sustainable Solar Buildings

Keywords: Solar energy in buildings, Low energy buildings, Bioclimatic Architecture, Energetic efficiency.


PSE-ARFRISOL aims to increase society’s awareness of Bioclimatic Architecture advantages. For this purpose, a journalist has been hired by the research group to be in charge of the diffusion plan, to publish and spread news about the project in mass media. This strategy intends to attract the attention and broaden the mind of society regarding energy efficiency in buildings. Spanish Ministry of Innovation and Science wants to introduce this formula in R&D national diffusion plan.

The advantage of Spain and the rest of Europe is that, nowadays, bioclimatic architecture is being promoted by their respectives governments. Often, people relate energy efficiency with solar collectors and photovoltatics panels. The objective of PSE-ARFRISOL Group is to prove how an architect can make Bioclimatics Buildings with equivalent costs. Ventilated facades, walls with high thermal inertia, cross ventilation and specials windows with shadowings are only same ways for the design of this kind of buildings, but the most effective way is to take into account the climate, the environment and the orientation of the building.

This ideas intend to change the current situation: the consumption of energy has increased by 5% since year 2000, approaching the energetic level of Northern European countries, in spite of the warmer climate in Spain. Nowadays more than 30% of the total consumed energy in Spain is used in buildings in order to achieve the thermal comfort. The newspapers are worried about it because they published these news. Also the 25% of the pollution is for the same reason. Besides according to the spanish energy efficiency plan elaborated by IDAE, (Spanish Institute for Saving and Diversification of the Energy), in the construction area the profesionals implicated have to analyse the way of reducing the levels of energy consumption of HVAC systems.

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Подпись: F.5

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These five buildings, (from now on, called Research and Demostration and Building Prototypes-RDBP) will be used to obtain data about the saved energy and then, to show them to the Society. This Project is supported by the Spanish Government, the materials used and the companies involved must be Spanish and have certain guarantees of quality. Recently Spain has approved a Technical Code of Edification (CTE) about security and Efficency Energy in buildings. A hard work that includes changing the ideas of the builders and architects.

The PSE-ARFRISOL involves the most important building enterprises, (DRAGADOS, OHL, ACCIONA, FCC) and the best Spanish technology companies (UNISOLAR GROUP, ATERSA, GAMESA SOLAR, ISOFOTON and CLIMATEWELL) with some prestigious research centres, (CIEMAT, OVIEDO UNIVERSITY, ALMERIA UNIVERSITY and BARREDO FOUNDATION). All them have signed an implementing agreement to carry out the project.

The tasks of this project are divided in 9 subprojects (SP’s), 5 of which are the office buildings constructions. PSE-ARFRISOL will provide every RDBP with different strategies for each location of the Spanish geography and climate conditions. From SP2 to SP6 the subprojects are the contraction of CIESOL-office RDBP at Almeria University, (Almeria); ED-70 RDBP — office enlargement of an existing building at CIEMAT (Madrid), PSA — new technical office RDBP at the PSA (Tabernas Desert, Almeria), a new office RDBP at Barredo Foundation (Siero, Oviedo) and the rehabilitation of an office RDBP at CEDER (Cubo de la Solana, Soria). SP 1 includes all the previous studies, SP 7 consists in the RDBP’s monitoring for thermal analyse and air quality study, SP 8 is R&D in HVAC systems and, finally, SP9 will spread the results and transfer the information extracted from RDBP’s to the society.

Project Results

This project whose central objective was to use renewable energy technology to break the barrier which had held rural women back from full participation in SMET education and the national economy produced good results in the short term and holds a promise for the future. Activities were designed not only to use the technology to alleviate the suffering and poverty in the rural community but more importantly, to cultivate young women’s interest in science by demonstrating to them that science can provide a solution to many of their every day problems.

In this section we first list the indicators we used to determine our goal attainment and then follow up with numeric results.

1.3. Indicators Used to Determine Goal Attainment

Indicator One: Reduction of the drudgery imposed on rural women and girls by the

lack of electricity and water supply, thereby freeing up their time to pursue productive economic and civic activities — education, and improvement of quality of life for women and girls.

Indicator Two: Young girls interest in Science, Mathematics, Engineering and Technology (SMET) education and Career.

Indicator Three: Increased contact between rural women and the rest of society for civic and democratic activities, as well as economic activities.

Indicator Four: Involvement of more rural women in socioeconomic activities.

Thesis project

This is currently run over about three months during the spring semester. SERC offers a range of topics for projects, most of which are related to ongoing research projects or for building up the infrastructure for the ESES programme itself, such as new labs. In addition students are encouraged to search for projects at other research institutions and business companies, may be in the home country. However, the students can also create their own research topic and the staff tries to find suitable supervisors, which has been possible most of the time due to SERC wide range of contacts.

2. Experiences gained

The programme is run in Borlange, Sweden which has a long winter with resulting restrictions in solar experiments. To deal with this, the practical parts of the courses are ordered in such a way that those that require good solar conditions are placed at the start of the academic year. Examples of these are: radiation sensors and measurements; solar heating system experiment and PV experiments. As the programme has become more popular, with classes of over 20 students, several lab groups have become necessary, restricting the flexibility for reserve times for the experiments. SERC has thus purchased a small solar simulator with 1000 W/m2 over approximately 0.8 * 0.8 m2 at a distance of 1.8 m from the lamps. While the simulator is relatively simple, with a variation of 10% in radiation over the 0.64 m2 application area, it is sufficient for smaller indoor experiments of the sort carried out in the courses, making it possible to make experiments with PV panels, solar collector models or testing of box-type solar cookers. The use of the simulator automatically leads to interesting discussions of indoor contra outdoor testing.

The students come from a range of academic backgrounds, both in terms of teaching traditions and subject areas. Students are admitted with degrees in electrical-, energy — and mechanical engineering, physics and chemistry. This means that some students have extra work for certain topics that they do not have a thorough background education in. A revision of some basics is thus necessary in some of the course blocks. A larger problem, encountered in many similar master programmes, is the different academic traditions. The Swedish tradition involves a significant amount of independent work and own initiative, with frequent seminars and discussions.

2.1. Course work

The majority of the courses are given by lecturers at Dalarna University College, but certain parts are given by external experts, among them a guest professor from India. This has worked well and adds to the international flavour of the programme.

Most courses have a traditional written examination at the end in addition to compulsory laboratory work. However, in the course where solar architecture and passive solar engineering is taught (main part of the course Passive solar energy technology), a new examination form has been tested. Since the lectures are grouped in different topics, like passive solar engineering, building physics, daylighting etc, the students have to write a short paper after each topic. In this the student has to compare his/her new knowledge from the lectures to his/her own experiences, such as the situation in his/her home country and additionally comment on how the new knowledge can be used professionally in the future. These papers, together with some small home exercises, are the basis for grading the students in the course. It has been found that this is a good training in critical writing, especially for students from universities and degrees with little tradition of writing such reports.

The Solar thermal design course is a design project for solar thermal systems, the sort of task carried out by consultants. This involves lectures on solar thermal systems, basic hydraulic design and sizing. The task is to design a system with minimal costs for given target solar fraction and boundary conditions (load, climate, building). The students are given different system designs to use and at the end of the project, the students compare and discuss the different results, a process that has proved to be very rewarding for the students (and lecturers). In the process of the project the students use the simulation programme Polysun (7) and a database of cost functions for relevant components. During the project, the students get theoretical lectures that provide knowledge required in the solving of the task. The project has got very good reviews from the students.

As part of the PV/Hybrid system design course a PV mini project is carried out by the students. The aim of the project is that the students understand how standalone PV systems work and how the performance of the systems can be evaluated based on measurements. The project is performed in groups of two students. It includes design, the installation of a complete stand-alone PV-system by each group, including connecting all electrical components and measurement equipment, a monitoring period of 2 weeks and evaluation of the data. The project has proved to be valuable as a preparation for the thesis project in terms of gaining more experience in setting up and evaluating measurements as well as writing the project report.

This course, PV/Hybrid system design, has also been given as distance learning with about 30 registered students. In this case the PV miniproject was replaced by giving the students a lot of measured data of insolation, current and voltage from a PV/Wind hybrid system to evaluate. However, four months after the course is ended none of the distant students has finished the course. The reason for that has to be found and improvements of the course have to be done.

2.2. Projects

Many of the thesis projects have been carried out at SERC. However, an increasing number have been carried out at companies and research institutes in other countries, often the home countries of the students. In these cases, the students make their own contacts with the company/institute they want to stay at, as well as all practical arrangements like place to live and travel. The supervisor at SERC has to accept the thesis topic and a letter of agreement is established between the two parts. Dalarna University College pays no expenses for the host institute, however our experiences are solely good from these arrangements. Since the thesis work has to end with a final thesis seminar, the students come to Sweden at the end of the semester to defend their thesis. Alternatively, the student can contact a university in their home country that can organize an official seminar with an opponent (often a student in a similar academic field as the ESES student).

In addition to the thesis project, a group of 2006 year students and a group of this years students have entered the Frisian Nuon Solar Challenge, a solar boat race in Holland during July 2006 and June 2008. This has proved very motivating for the students, involving the use of the knowledge gained in the programme but also testing their skills in communication (acquiring sponsorship) and working in a multi-disciplinary team. In the first boat race our students got Bad Luck Price, but this year several improvements were made thanks to generous sponsoring and our students got place 12 in the result list. SERC will encourage students to compete even in future competitions.

2.3. Alumni

A survey, where a questionnaire was sent to 58 former students who had finished the programme, has shown that a large number of former ESES students has succeeded in starting their professional career in the area of solar energy or energy in general. (A total of 89 students have today completed the ESES programme.) Of these, 45 replied to the questionnaire. The results show that of the 45 who replied, 30 are currently active in the field as PhD-students, researchers, sales managers or engineers. About half of them work in research related areas that proves that the ESES programme is also a good starting point for an academic career.

In 2005 a group of former ESES students established the Alumni organisation “ESES-Collective”. The organisation is official registered in Sweden and has the following objectives:

• To support the work of ESES in educating students in the development and implementation of environmental friendly energy technologies

To help students to find suitable thesis projects, internships and jobs Form a network of solar interested people worldwide

If sufficient funds can be obtained, support will be given to students for study materials and books as well as project support.

The organization is currently working on a website (www. esescollective. com) that will also include a job exchange for solar related jobs. A number of books have already been donated for use of the actual ESES students.


[1] L. Broman, K. Blum, V. Garofoli, L. Kristoferson, U. Kusoffsky, and B. Hidemark. Creating a European Solar Engineering School. In Anil Misra, Ed., Renewable Energy Education — Current Scenario and Future Projections, pp 42-47. Tata Energy Research Institute, New Delhi (1998).

[2] G. Boyle. Renewable energy, power for a sustainable future. Oxford university Press (2004). ISBN 0-19­926178-4.

[3] J. A. Duffie and W. A. Beckman. Solar Engineering of Thermal Processes. John Wiley & Sons, New York (2006). ISBN 0-471-69867-9.

[4] T. C. Kandpal and H. P. Garg. Financial Evaluation of Renewable Energy Technologies. Macmillan, New Delhi (2003). ISBN 1-403-90952-0

[5] T. Markvart. Solar Electricity. John Wiley & Sons, New York (2001). ISBN 0-471-98853-7

[6] L. Broman and J. Gertzen. ESES, a European Master’s Level Programme in Solar Energy Engineering. Paper presented at 8th International Symposium on Renewable Energy Education, Orlando, Florida (2002).

[7] Solar Energy Lab SPF. Polysun 3.3 solar thermal simulation program. Computer program for Windows, version 3.3. SPF, Rapperswil, Switzerland. www. solarenergy. ch (2002).

Conclusions and next steps

There is growing interest in highly glazed building facades, driven by a variety of architectural, aesthetic, business and environmental rationales. The environmental rationale appears plausible only if conventional glazing systems are replaced by a new generation of high performance, interactive, intelligent faqade systems, that meet the comfort and performance needs of occupants while satisfying owner economic needs and broader societal environmental concerns. The challenge is that new technology, better systems integration using more capable design tools, and smarter building operation are all necessary to meet these goals. The opportunity is to create a new class of buildings that are both environmentally responsible at a regional or global level while providing the amenities and working environments that owners and occupants seek.

BIPV systems could be applied both for existing buildings, and for new ones. They could be introduced on roof coverings, as facades and as skylights/shading devices.

An important requirement for operation at optimum parameters would be that the PV panels were not shadowed.

The BIPV systems could represent for Romania, as well as for developed EU countries a very good solution to be considered in the buildings industry. Although it is not cheap, it could be adopted in the future based on corresponding public education and on legal support granted by specific fiscal facilities.

In June 2008, a BIPV Laboratory developed at Physics Department of PUB and IPA SA was put in operation. It contains: a BIPV system, a monitoring station for measurement of weather parameters and an installation for monitoring of main BIPV physical quantities (see Fig. 2 (a), (b), (c)).

Other two BIPV demonstrative systems must be installed on two pilot buildings: in Bucharest (it will integrate an historical building) and in Timisoara (a new building will be considered). They will have different typologies and we will consider new technologies for PV modules integrated in the architecture of the selected buildings.

Fig. 2. BIPV Laboratory Polytechnic University of Bucharest (PUB); (a) outside view of the BIPV window installed at Physics Department, PUB; (b) Meteorological Station installed at BIPV Laboratory, PUB; (c) inside view of the BIPV system including the inverter and the monitoring station for PV parameters




[1] IPA SA (coordinator), WUT, PUB, TUT, UAUIM, Promotion of Solar Architecture in Romania (PASOR), Project No. 21039/2007, Research Romania’s Partnership Programme

[2] Nordmann T., July-august 2005, Built-in-future — integration, technical and market issues for PV, Renewable Energy World, 8, no.4.

[3] Harvey D., 2006, Low-Energy buildings and District-Energy Systems, 384 pages, James & James Ltd.

[4] Prasad D. and Snow M., 2005, A Source Book for Building Integrated Photovoltaics (BIPV), 256 pages, EarthScan

[5] http://buildingsolar. com/technology. asp

[6] http://www. terrasolar. com/bipv. html

[7] www. domainnames. com.

[8] www. pvnord. org

Lab and GIS Equipment for Teaching Solar Energy

D. Strebkov, I. Tyukhov*, M. Schakhramanyan

All Russian Research Institute for Electrification of Agriculture, 1-st Veschnyakovsky proezd, 2, Moscow
109456, Russia1, Moscow, Russia, Tel: (495) 171-05-23, 171-19-20, Fax: (495)170-51-01:

* Corresponding Author, ityukhov@yahoo. com


The solar industry and growing PV market is looking for good prepared in solar energy young people. Students are interested in how to learn more about clean renewable energy. With the lesson plans that are now being developed for renewable energy in a number of Russian universities, there is a pressing need for corresponding hands on experience either of lab equipment (indoors) and or photovoltaic (PV) systems installed in test fields (outdoors) to augment enhance the educational experience. This paper is about solar energy lab equipment and geographic information system (GIS) developed at the UNESCO Chair on Renewable Energy in the All Russian Research Institute for Electrification of Agriculture (VIESH) and at some Russian universities to help teaching the principles of solar energy and GIS systems.

Keywords: solar cell, concentrator, geographic information system, solar energy, education and training

1. Introduction

For a real extension and implementation of renewable energy resources engineers, technicians, scientific experts and project workers are needed. Moreover a broad understanding of the subject among all engineers, designers, technicians and experts (and even among politicians and decision makers) who is linked to the subject is necessary. In this context the UNESCO — MSUAE Chair “Renewable energy and electrification of agriculture” in the All-Russian Research Institute for Electrification of Agriculture (VIESH) and jointly with the V. P. Goryachkin Moscow State University of Agricultural Engineers (MSUAE) are developing strategies concerning the educational recourses including laboratory equipment (lab kits) on renewable energy. The UNESCO — MSUAE the Chair is guided by principle connecting education and research work. Education programs inspire students to explore sustainable energy solutions to meet our future needs.

Teaching Physics at the Moscow Power Engineering Institute (MPEI) one of the authors started to develop special topics and demonstrations of solar energy principles in the General Physics courses (some papers were published in English). Some work was done on solar education during JFDP program, other in framework of Fulbright program.

Population samples definition

2.1. Characterization of studied locations

In order to characterize each studied city, it was performed a statistic evaluation based on maps, surveys and analysis, related to social, economic and physical factors, to reach the total number of systems to be visited. This research had focused on the analysis of demographic density, average number of households per neighborhood and family average income, as exemplified in the Figure 1 below:


Figure 1. Average Number of Households per Neighborhood, Demographic Density and Family Average Income of Belo Horizonte — Source: (www. pbh. gov. br) and IBGE (2006).

. Solar assisted process cooling at a radiological practice in Berlin

At the radiological practice Dr. Reichel & Dr. Gehrmann, a solar assisted cooling system in order to remove mainly the loads from the tomography equipment of the practice went recently into operation in July 2008. The practice is located in the Rheineck-building, a landmarked and refurbished building, used by several commercial companies (figure 6). A central chilled water network, operated by an electrically driven compression chiller, distributes chilled water to the enterprises in the building. Cooling demand in the radiological practice occures day and night and throughout the year, since the supra-conductive solenoid has to be cooled continuousely. With the installation of the additional solar cooling system, cold consumption from the chilled water network is reduced during the day.


Absorption chiller

Подпись: Chilled water Figure 7 Simplified scheme of the solar assisted cooling cooling system at the radiological practice in Berlin.

10 kW

The solar cooling system consists of 40 m2 vacuum tube collectors of the company Phonix Sonnen — warme AG, and of the high efficient suninverse absorption chiller from Sonnenklima, Berlin, with 10 kW rated chilling capacity. In this application, the collector fluid is pure water as well. The chiller is combined with dry heat rejection with water spray option in case of high ambient temperatures. During winter, the heat rejection system will be used for free cooling at sufficient low ambient tempe­ratures in order to contribute to the cooling load coverage. Due to the limited installation area, the whole plant is a roof-top installation. The monitoring system is going to be installed and operated by the Technical University Chemnitz. A scheme of the system is shown in figure 7.

As a consequence of the continuous cooling demand of the practice throughout the year and due to the limited size of the plant, the coverage of the cooling load by the solar thermally driven system will be quite small; simulation calculations have revealed primary energy savings in the order of 15% annually

with some uncertainty, since by the time of the calculations the final type of the tomographic equipment was not known precisely. Nevertheless, the concept is promising in order to demonstrate the general applicability of process cooling with a high efficient absorption chiller and dry cooling as well as with free cooling via the hybrid re-cooling system.

Additional equipment

An attractive feature, specially for children, is a model electric railway powered by PV.

Another novelty is an electronic set of bagpipes powered by PV (The driver is a piper).

When the van is on site, the solar water heating panels are folded outwards and connected to a bucket of water on the ground. The PV pump circulates water between panels and bucket and the public are invited to feel the water in the bucket. They are usually surprised to find that it is warm or hot, even on cloudy days.

4. Schools visits

Over the last two years, Solar One has visited nearly 200 schools all over Scotland. The normal programme is for a talk to be given inside the school, then groups of 10 or so pupils come outside to see both the inside and outside of the van.

Water heating system

A solar water heating system is in place to meet the hot water requirements. While a solar water heater taps the sun’s energy directly, a series of photovoltaic panels capture the energy and store it by charging a bank of batteries. The solar panels, each measuring 1.1 by 1.2 meters, are joined and form an integral part of the roof of the building. Photovoltaic panel also powers the water pump.

4. Roof innovatively to admit maximum daylight

Подпись: Roof insulation

image118 image119 Подпись: fixed

Подпись: covering maximum area of

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Roof design

Fig. 3: Critical Roof Design parameters.