Category Archives: EuroSun2008-9

Solar assisted air-conditioning at the Technology Center of FESTO

In 2001, the new energy efficient buildings of the Technology Center of FESTO AG in Berk- heim/Esslingen were completed. The area comprises 26,000 m2 of air-conditioned office and computer services area and additionally moderately air-conditioned atria area. In order to use waste heat from the production facility nearby, three thermally driven chillers are installed with a rated chilling capacity of 350 kW each (total: 1.05 MW), to supply cold for slab cooling and supply air cooling of the Tech­nology Center. The installed cooling technology are adsorption chillers from the Japanese manufac­turer Mayekawa. At rated conditions, the total heat input for the chillers is approx. 1.7 MW. However, during operation of the plant it turned out that less than the originally expected 0.8 MW of waste heat was available. Remaining heat input for the chiller operation is provided by gas boilers. Figure 4 shows the Technology Center and one of the adsorption chillers.

Within Solarthermie 2000plus, a vacuum-tube collector system is added as third heat production sys­tem to assist the chiller operation in summer and for heating support in winter. The collector system consists of 1218 m2 aperture area of CPC Star Azurro collectors from Paradigma. At present, this col­lector is the largest system operated with pure water as collector fluid. At low collector temperatures with danger of freezing, a special control allows periodically circulation of the collector fluid for some seconds in order to transport heat at a low temperature level into the collector. In winter, solar pro­duced heat is used for slab heating at temperatures < 50°C in a new office building of the company. The collector went into operation in the end of 2007; the monitoring system was installed and is operated by the University for the applied sciences Offenburg. Figure 5 provides a scheme of the system.

Electrical system

Electrical generation is from a combination of a 40Wp PV donated by Solar Century Ltd and located on the roof of the van cab and a 100Wp wind turbine donated by Ampair Ltd located on the roof of the van on a hinged frame so it can be lowered when the van is being driven. Electricity from both these sources goes via controllers into a twin battery pack(total 120Wh), lead-acid type, located on the floor of the technical compartment. Some appliances are driven by the 12V direct current from the battery but most are powered by 230V AC from an an invertor driven by the battery.

3. Van body

The van body is divided into two compartments. The larger is the public/living room which is nicely furnished with carpets, a table and chairs and pictures on the wall. A mural painted by a local artist showing all renewables is on one wall and an array of leaflets and brochures on all renewables is on another. This compartment has underfloor heating fed from the solar storage tank. It has a translucent roof to maximise daylight and its window to the rear is double glazed with low-e glass and an argon infill. Access to this compartment from outdoors is via a set of aluminium steps with handrails which can all be folded up for transport.

The second, smaller compartment is forward of the larger compartment and is the technical/sleeping compartment. It houses the thermal and electrical storage systems, the control and display systems, a sink for washing and a shower. It also has a bunk bed for the driver.

Waste-water recycling

All wastewater (grey water) is treated, through a process of filtration, aeration and ionization to be reused for gardens in a way that such water eventually percolates into the open wells and so completing the loop of use and generation. This treated water is also used in the toilets.

Kitchen wastes are segregated into organic /inorganic wastes. Organic waste goes to the vermicomposting pits where they are converted into Vermicompost, a nutrient-rich natural fertilizer and soil conditioner to be used for the garden.

3.6 Energy management through innovative interventions

Intelligent lighting systems blend motion sensors, ambient light sensors and timers to ensure that lights are switched off when not needed. Compact Fluorescent Lamp (CFL) and Light Emitting Diode (LED) based bulbs serve as highly efficient illuminating systems reducing CO2 emissions (1 CFL saves 0.1 tonnes of CO2 per year) and reduces power consumption by up to 80 per cent while protecting lighting efficiency. Nano-technology based solar lighting system (like quantum dots) for dwelling houses is expected to be close to 100% efficiency, energy and economy too.


The first thermal regulation was adopted in 2000 and now is going to be published the second phase concerning the thermal requirements of the building envelope elements (windows, walls and roofs). Although the existence of the thermal regulation, the social houses in Chile, have enormous deficiencies related with the thermal insulation application, ventilation and condensation [2]. In this context a proposal was prepared, to start in 2006, with the principles and the design guidelines for the social houses rehabilitation [2]. One of the measures proposed consists on the improvement of the envelope thermal quality: roof thermal insulation replacement, inclusion of thermal insulation on the external walls, replacement of single glass by double glass windows. In what concerns the passive solar systems the interventions will focus on solar walls for heating with and without ventilation, solar collectors and accumulator collectors for water heating.

Development of a Training Course on PV Systems Installation

Miguel C. Brito7*, Joao M. Serra7, Jorge Maia Alves7, Killian Lobato7, Ivo Costa7, Antonio
Vallera7, Carlos Rodrigues2, Susana Viana2, Antonio Joyce2

1 SESUL, Faculty of Sciences of University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal
2INETI, Department of Renewable Energies, Campus do Lumiar do INETI, 1649-038 Lisbon, Portugal

* Corresponding Author, mcbrito@fc. ul. pt


The deployment of photovoltaics in large scale, in particular PV microgeneration, requires the development of a numerous workforce trained for PV systems installation and maintenance. Since there is an obvious lack of local training opportunities for PV professionals, the University of Lisbon and INETI have promoted a new Training Course for PV System Installation with special emphasis on hands-on practical experience and safety issues.

Keywords: PV systems, training, installation

1. Introduction

The full potential of photovoltaics, as microgeneration in residential urban context as well as in off-grid stand alone systems, can only be successfully achieved through the appropriate training of the PV installation professionals. In Portugal, where a recent law has defined the framework for the development of microgeneration, it is expected that this sector will witness a fast increase. However, if these systems are improperly designed, incorrectly installed, not properly maintained or if the users are not instructed in the proper use and routine maintenance, they will fail to meet performance expectations, or they might fail altogether.

Since there is an obvious lack of local training opportunities for professionals in this field, we have developed a training course on PV Systems Installation. The non-availability of similar training courses, certified or non-certified, required that the proposed training course should fulfil two objectives: i) prepare the participants for the installation of PV systems; ii) set a quality standard for other training courses expected to be organized in the future.

For the moment, the PV System Installation Training Course is open to professional electricians (Level III) only. In the foreseeable future, however, and as a result of partnerships to be developed with professional schools, it is expected that the training course might be offered within a broader context as a Professional Course of PV Systems Installation.

This training course was developed in a partnership between University of Lisbon and the Renewable Energy Department of INETI and tries to combine a solid theoretical preparation with hands-on practical experience.

The Course on Photovoltaics at the CTU in Prague

At the Faculty of Electrical Engineering of the CTU in Prague a course on Solar Energy Exploitation Systems, mostly oriented in the field of photovoltaics, was introduced in 1995 as an optional course. The course was developed to give undergraduate students information about the full set of important problems connected with photovoltaics from photovoltaic effect, cell construction and technology to applications, including operating conditions and economical and ecological problems. Details about the course were published in [3]. Since the school year 2006/7, a course in Photovoltaic Systems, dealing with PV system technology (28 hours of lectures, 28 hours of exercises) forms part of the master study programme in Electrical Engineering and Information Technology. Synopsis of lectures on Photovoltaic Systems is shown in Table 1. Education in Photovoltaics at the CTU in Prague has been in more details described in [4].




Solar energy (spectra, geographic position and influence of climate).


Photovoltaic effect


Solar ceiis, basic structure and characteristics


Singie-crystaiiine, polycrystaiSine and thin film solar ceiis


Construction and technology of highly-efficient solar ceiis


Construction and technology of PV modules


Modules with concentrators, hybrid systems


Photovoltaic systems — basic types


Stand-alone systems. Grid-connected systems


Energy storage for photovoltaic systems


Applications of photovoltaic systems


Operating conditions of photovoltaic systems


Economic and environmentai aspects of photo voltaic s


Present trends in the field of photovoltaics.

Table 1. Synopsis of lectures on Photovoltaic Systems

2. Exercises

Exercises are a very important part of the course orienting the course in a particular direction. The developed laboratory exercises deal with photovoltaic system applications, and are adapted to the requirements of electrical engineers. The exercises have been divided into three blocks. The first block deals with detailed measurements of PV cell characteristics and the influence of important external parameters (light intensity and temperature) and internal parameters (series and parallel resistance) on the shape of these characteristics and on cell efficiency. PV cell measurements are performed on square (102 mm x 102 mm) silicon cells (both single-crystalline and poly-crystalline) using


Подпись:illumination with a halogen bulb. The basic circuit used for measuring I-V characteristics in all four tasks is schematically shown in Fig.1. From measured characteristics parameters VOC and ISC and the maximum power point characterised by Vmp and Imp are extracted. Results of measurements are dependences of VOC, ISC, fill factor FF and maximum power Pmp on given parameters [6].

The second block consists of three laboratory tasks concerned with measuring the

Подпись: characteristics of PV modules: • measurements on a solar module - dc load system • measurements on a solar module - charge controller - battery - dc load system

• measurements on a solar module — dc/dc — dc/ac system

Подпись: Fig. 2. Laboratory exercises with set of halogen lamps Подпись: Fig.3. Homogeneity of irradiance on the module are in the laboratory equipment

For measurements on modules are used 26 Wp standard (12 V) modules and they were performed in last courses in front of the building using natural sunshine. The measurements outside of building were relatively strongly influenced by the temporary weather. Even from one viewpoint it gives students a sample of real applications, from another viewpoint it complicates the exercise programme that should be performed in accordance with a given timetable. For this reasons there have been prepared laboratory measurements on PV modules using set of halogen lamps and reflecting walls as a solar source, as shown in Fig 2. The homogeneity of irradiance on the module area is very good, differences from the mean value are less than 5%, as demonstrated in Fig.3. A disadvantage of using halogen bulb is, that the PV modules must be cooled (a van below the PV module can be seen in Fig.2.).

image076 Подпись: Rz

One of the circuits used (for measurements on an off-grid PV system with battery and inverter) is shown in Fig.4.

At measurements, problems with connection of PV modules in parallel and in series, influence of partial shading on I-V characteristics are also demonstrated.

The third block of tasks analyses data obtained from an on-grid demonstration PV system, and includes a small, simple photovoltaic system project (both off-grid and on-grid). To demonstrate the function of photovoltaic systems in real operating conditions, a 3kWp demonstration, on-grid connected photovoltaic system has been built at the Czech Technical University in Prague on the roof of the Faculty of Electrical Engineering. (This installation has been supported by the State Fond of Environmental Policy of the Czech Republic and has been realised by the company Solartec s. r.o,

Roznov p Radostem.) The block diagram of the system is shown in Fig.5. The photovoltaic modules are situated at the flat roof of the Czech Technical University, Faculty of Electrical Engineering with the aim of demonstration a photovoltaic system (on-grid connected) and of evaluating the potential of using roof top photovoltaic systems under conditions of real urban utilization. This system allows monitoring of data about performance of three photovoltaic fields with different tilt angle. Collected data give important information about system performance in both fa? ade and on-roof applications. Input and output data (dc voltage, dc current, ac voltage, ac current, instant power and energy produced) supplemented by PV field temperature and intensity of solar radiation are available online at http://andrea. feld. cvut. cz/fvs.

Synopsis of laboratory exercise on Phtovoltaic Systems is shown in Table 2.




Organization, introduction


Laboratory measurements on solar cells — explanation


Comparison of V-A characteristics of different solar cells


Influence of series resistance on solar cells parameters


Influence ofparallel resistance of solar cells parameters


Temperature dependence of solar cell parameters


Laboratory measurements on PV modules — explanation


Measurements of solar module characteristics


Measurements on a solar module — dc load system


Measurements on a solar module — dc/ac system


Grid-off PV system design (simulation)


Grid connected PV system (simulation, demonstration)


Technical visit at 40 kWp grid-connected PV system


Final test

Table 2. Synopsis of practical exercise

4. Conclusions

The course on Photovoltaic Systems oriented in the field of photovoltaics performed at the Faculty of Electrical Engineering of the Czech Technical University in Prague at the undergraduate level has been discussed. The course gives information on both device and application approach with application oriented laboratory measurement tasks. Laboratory measurements are prepared to give student practical knowledge about cell characteristics, module characteristics and system behaviour. The course has become suitable for all branches of study in the field of electrical engineering.


[1] Hirshman W., Herring G. and Schmels M.: Gigawarts — the measure of things to come, Photon International, No.3, 136 — 166, (2007)

[2] Jager-Waldau A., PV Status Report 2006 (Research, Solar Cell Production and Market Implementation of Photovoltaics), Office for Official Publications of the European Communities, Luxembourg (2006)

[3] Benda, V, Development of a Course on Photovoltaic Systems. Solid State Phenomena. no. 97-98, pp. 133- 138.(2004)

[4] Benda, V., Education in the Field of Photovoltaics at the Czech TechnicalUniversity in Prague, this Proceedings, paper #269 (2008)

[5] Goetberger, A., Knobloch, J. and Voss, B.: Crystalline Silicon Solar Cells, J. Wiley & Sons., Chichester, 1998

The Active Solar Building — Overview of the SRA of the ESTTP and Synergy with other Technology


Volker Wittwer

Fraunhofer Institute for Solar Energy Systems, Heidenhofstr. 2, 79110 Freiburg, Germany


In this paper, an overview of the content of the strategic research agenda of the European Solar Thermal Technology Platform in the area of active solar buildings will be given. The vision for a sustainable energy supply of our buildings based mainly on solar energy will be presented as well as a review on short-term, medium-term and long-term research. In addition, the integration of this vision into the framework of the other technology platforms in the area of renewable energy is shown. Beside some competition, many synergetic effects are possible, which will help us to create a sustainable energy supply system for the future.

Keywords: energy-efficient buildings, solar collector, energy supply system,

1. Introduction

Подпись: Figure 1: Annual available renewable energy in comparison to the demand.

The decision of the European governments to reduce the energy demand by 20% by 2020 and to supply 20% of the energy demand 20% by renewable energy forces all countries to strengthen their activities in the field of renewables. If the worldwide potential of renewables is analysed, solar energy is found to have the highest potential (figure 1). Therefore solar energy should be used wherever it is possible. Of course there might be some places, where geothermal or available district heating systems might be preferred or combined with solar systems but in general solar energy could be our main resource in future.

If the final energy demand is examined in detail, the result for Europe is that heat is the dominating component with roughly 50 %, followed by energy for transport with 30 % and electricity with 20%.

The total heat demand is dominated by the heating demand of our buildings followed by the process heat demand of the industry. Thinking about the European goals of 20% reduction and a 20% contribution by renewables by 2020, the reduction of the heating demand in buildings and the increased integration of solar systems are fundamental approaches to reach these goals.

In 2005 a preliminary steering committee for the European Solar Thermal Technology Platform was founded by researchers and industry under the administrative leadership of ESTIF and EUREC to work out a vision paper and a strategic research agenda, which should show how we can reach this goal.


The major advantage of involving users in the innovation process is the convergence of ideas and efforts to match exactly buyer’s needs. The specification of certain characteristics in some products allows manufacturers to develop and improve, products that capture common users attention and also users whose needs are based in more detailed products and for whom specific products are not easy to find. In this way a more demanding parcel of the market is addressed and captured.

Although designed to satisfy a rather strict community of users, to whom the strategy of “few sizes fit all” does not adequate (Von Hipel, 2006), user product innovations are expected to benefit directly their developers, while manufacturers only expect to benefit by selling their products, a fact that increases innovators impel to create novel products. Directly involving users in the product design process can be seen as an advantage, as customer ideas can complement the R&D performed in the company, improving productivity of new products. Users can also be good allies in establishing the optimum price/performance combination and, if the relations established with the customer at an early stage are good, the interaction manufacturer-customer may extend throw the life cycle of the introduced innovation. In fact several studies have found that commercially viable products tend to be developed by “lead-users” that anticipate market needs and develop products from which they expect to benefit greatly. (Baldwin, Hiernerth and Von Hippel, 2005)

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.

image187 image188

Подпись: F.5

image190 image191

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.