Category Archives: EuroSun2008-9

Testing course modules

Подпись: Fig. 2. Modules testing with high-school teachers.

In order to assess the curriculum, and get the feed back from the teachers-trainees, testing sessions were proposed. Thus, the first form of the materials was tested in Brasov (Fig. 2), in June 2007 with high-school teachers from Turkey (11 persons, having different backgrounds: technical, scientific, humanities) and Romania (6 persons, having scientific and technical background), who were selected by the two school inspectorates. The lectures were delivered by teachers from Transilvania University of Brasov and College for Natural Sciences, Brasov. Seven modules of the in-service course were, thus, assessed: Fundamentals of energy production, Solar-thermal systems, Photovoltaic systems, Wind systems, Micro-hydro systems, Waste management, Waste water treatment.

The trainees were involved in several types of activities: traditional lectures, where the new scientific content was presented; in experimental sessions — they were involved in real active learning activities in laboratories from Transilvania University, focusing on renewable energy systems; project-based learning sessions — each teacher had to propose a lesson plan meant to design the appropriate learning environment dedicated to the knowledge and skills acquisition in the field of renewable energy, in the

frame of the own taught discipline. All the teachers positively appreciated the entire course;

The topics approached by the teachers were related to: wind energy systems, photovoltaic systems, solar-thermal systems, environment pollution. All the plans approached the traditional instructional method: teacher delivering the content, students trying to acquire the new content, followed by an evaluation sessions. No experimental activities were proposed, and the reason for this was the lack of experimental devices in their schools. Teachers mentioned that the subjects they proposed were new; they don’t have the opportunity to integrate them in their curriculum, but they can further introduce them in the quotidian instructional activity to provide contextual learning for the “normal” topics in the school curricula.

Thus, the modules testing revealed a strong need of appropriate teaching aids — a combination of a teaching manual, eLearning tools and practical kits.

The testing of the full course was performed in Transilvania University, between the 1st of November 2007 and the 30th of May 2008. A number of 18 high-school teachers (Technical, Physics and Chemistry background) from Brasov and Covasna counties attended the course, while the lecturers were given by teachers from four of the partners’ countries (Belgium, Greece, Germany, and Romania). The teachers were involved in the same type of instructional activities as the first group: traditional, experimental, project-based activity. The attendees’ final project is targeting the development of a project meant to introduce the topic of renewable energy in the pre-university curriculum. Their proposals are oriented in three directions:

• Topic of “renewables” as context for the subject in the existing curricula. For example, in scholar chemistry curricula, there is the “hydrogen”, “water” topic. For teaching this topic, the Chemistry teachers proposed problem-based activities focusing on Hydrogen Technology. The students are expected to understand the implementation of Hydrogen Technology with its advantages and disadvantages;

• Topic of “renewables” as specific subject in the existing curricula. For example, the Physics teachers proposed the “energy” topic to be presented in a new format, focusing on “renewables”;

• New topics in the curriculum. The pre-university curriculum offers the opportunity to propose new disciplines at the school decision. Thus, the teachers proposed in each area of the curriculum (Sciences and Technical areas) new disciplines, such as: “Energy Efficient House” (problem-based approach as teaching method), “Environmental pollution” (proposed by Chemistry teachers), “Energy and Environment” (multi-disciplinary approach among Physics, Chemistry, Geography teachers).

The real implementation of the teachers’ proposals will be in the 2008/2009 academic year and the results are expected in several years.

There are more opening expected: in the Transilvania University is running, starting with the academic year 2007/2008 the B. Sc. program Engineering of Renewable Energy Systems (4 years) already well attended by students. Preparing the teachers, in the high-schools, for teaching on renewables is expected to lead to a further increase in the pupils’ interest for further studying in this field. The B. Sc. course can be followed by the M. Sc. course Engineering Design and Management of Renewable Energy Systems (running starting with 2003) and various Ph. D. programmes in the Centre Product

Подпись: Developing Education and Training on Renewables Fig. 3. Integrated education and training lines in the Centre Product Design for Sustainable Development 4. Conclusions
Design for Sustainable Development. Thus the development of a complete education and training line is offered, addressing different levels of competence form a broad range of target groups.

The SEE EU Tool project provides an European frame for teachers’ in-service training on sustainable energy, mainly on renewable energy systems.

During the SEE EU Tool project a complex training kit for teachers in-service training have been developed in the partnership. The training kit contains: a course, teaching materials (containing content and teaching aids), experimental devices (and the suggested teaching aids).

The teachers from pre-university educational system are willing to participate at training courses in this field and they consider being very important for themselves and consequently for their students.

The need for adapting the curriculum and the course to the teachers’ competences and to the pupils’ level is fulfilled by a harmonized cooperation between the project partnership and the testing group — teachers from the partner countries.

After completing the course, the teachers found many opportunities to introduce the topic of renewable energy systems in the scholar curricula.

The course is integrated in a complete education and training line on renewables, developed in the Transilvania University of Brasov, the Centre Product Design for Sustainable Development.

References

[1] Environmental Education Materials: Guidelines for Excellence Workbook — Bridging Theory and Practice, North American Association for Enviornmental Education, 2000.

[2] G. Steiner, A. Posch Journal of Cleaner Production, 14 (2006), pp. 877-890.

[3] SEE EU Tool project website http://www. unitbv. ro/Default. aspx? tabid=561

[4] I. Visa, A. Duta, D. Perniu, International Conference on Trends in Environmental Education, EnvEdu (2006), Brasov, Romania

The proposed method in the ThERRA project

1.3. What is the energy production?

In 3.1 the difference between the input and output method is shown. This gives a large difference in the figures. An example for the Netherlands shows the following figures:

Global insolation: 3.6 GJ/m2/year

Insolation under optimum angle 4.0 GJ/m2/year

Collector output 2.0 GJ/m2/year (assuming 50% average collector efficiency)

System output 1.0 GJ/m2/year (average for 120 measured systems)

Energy saved 1.5 GJ/m2/year (65% efficiency for a reference hot water system)

It shows that the production of solar thermal systems varies between 4.0 GJ/m2/yr (1111 kwh) and 1.0 GJ/m2/yr (278 kwh) if you vary between the input method and the output method.

To make the figures independent of the insolation a formula was proposed by Jan Erik Nielsen from Estif.

E = C * A [m2] * G [GJ/m2]

C = a coefficient dependant on the application.

A = average installed collector area in the monitoring year.

G = the global radiation for the optimal collector orientation for the monitoring year.

For the input method a coefficient of 80% was proposed in 2007, but new information shows that this would be considered too high. It would be logical to take the average collector area for the typical application. For glazed collectors and hot water systems the coefficient would be around 0.50.

For the output method the coefficient can be calculated from monitoring data. Examples from the Therra monitoring project are [12]:

Output coefficient C:

The Netherlands: 0,25 (50 systems)

France: 0,29 (large systems)

France 0,14 (120 small systems)

There is a large difference in the performance. Especially large systems show a lower performance (but a higher solar fraction). More monitoring data should be analysed before an average default value can be given.

The potential for BIPV Product Development and Entrepreneurship in Portugal Evidence from the International Design Competition Lisbon Ideas Challenge

Joana Miguel Fernandes

IN+ Center for Innovation, Technology and Policy Research/Instituto Superior Tecnico, Lisboa Corresponding Author, iomifernandes@gmail. com

Abstract

Of the available portfolio of renewable energy technologies, solar photovoltaic materials, mainly due to their flexibility pasterns both in form and function, present exceptional properties for the application in the built environment, specially integrated in urban structures. The potential for the development of innovative urban structures integrating photovoltaic materials, namely by triggering entrepreneurial behaviours in actors that are usually "passive" users of the technology is the aim of this work. Among others, design teams are addressed as “users as innovators”, effective sources of innovation, in order to increase the creation of design inspired innovative products. The term “users” should in this sense be understood broadly to include those actors that use the technology in their daily practice and not only true end-users or beneficiaries of the technology. Acknowledging the importance of competitions as vehicles for the promotion and dissemination of new technologies, a preliminary assessment of the potential of Portuguese users to develop new products was conducted using as a testing ground an international design competition. Results showed a very positive response from the Portuguese public, even if there has been little or no previous contact with this technology. Even if taken restrictively, a conclusion emerges indicating that there is clearly a potential for PV-based urban-scale product development in Portugal, sourced in users. This potential enhances the need to develop policies devoted to promote “users as innovators”, by following capacity building strategies that enable users to engage in new product development.

KEY WORDS: Innovation, Photovoltaics, Users as Innovators, Design Competitions

1. INTRODUCTION

In the built environment, the integration of renewable energy sources (RES) is a strategy within the philosophy of demand-side management and among RES, solar photovoltaic technology (PV) presents the unique potential to be merged with the urban environment, transforming cities in distributed green-electricity production facilities. PV materials present high flexibility patterns, both in form and function, for the application in urban structures, in general and in particular in buildings. Conventionally, the value of PV systems is estimated considering only the electricity production value. In an integrative solution the strategy passes through the integration of the PV systems as construction materials, embedded in Building Integrated Photovoltaics (BIPV) and Photovoltaic Non-Building Structures (PV-NBS). The economic advantages of these application steam not only from the possibility of displacing dedicated land resources to structures surfaces, but also from the use of PV panels as a construction material performing a given set of functions additional to the production of electricity. The optimal combination of physical and aesthetical integration of PV technology in urban structures is expected to maximise the overall value of the PV system, even if the resulting structure corresponds to a situation where the system is not strictly optimised for its energy output. The intent is that for each object designed there will be a balanced combination of form and function, which will deliver a high-value product. (Rodrigues, 2004) Additionally the social values that arise from these applications must also to be considered, as it

contributes to the overall market value of the structure (e. g. aesthetical value, environmental sustainability image) and to foster the potential to develop the levels of education and public awareness. PV-NBS integration in the in the urban space takes advantage of the architectural quality of the PV materials and is achieved taking into consideration the technological efficiency of the systems according to the designed product electrical requirements. A wide variety of concepts from urban street equipment, to sound barriers, shelters and kiosks can already be seen in some cities, both off-grid and grid-connected. Nevertheless, technology dissemination is needed, in particular among the different actors relevant in the BIPV and PV-NBS market and within the wide public, whose perception and knowledge is essential to promote new technologies and remove possible public related barriers. The successful deployment of PV integrated solutions largely depends on how solutions, materials and integration possibilities are perceived by the ones that can actually use these new materials in their work, as architects, designers and engineers. The adoption of this new technology and awareness of its characteristics as a construction material requires adequate dissemination and knowledge transfer between actors, to allow it’s effective appropriation. This adoption process, as any innovation adoption process, goes through an acceptance and afterwards implementation path, as extensively described by Rogers and his model diffusion of innovations. It is expected that after a first good impression and implementation process have occurred, the user will start to integrate this new solution into his work, facing the new technology as an available material in his conventional portfolio. These technology adoption users mainly act as passive users of a technology. Nevertheless, this passive attitude can change as the user acknowledges the innovation properties and starts to develop a will to work the technology and adapt it according to the perceived opportunities as a response to his needs. This appropriation of the innovation can be described as the evolution of passive users into active users, ultimately leading to a situation where users may be seen as the source of innovation. The concept of users as innovators is an emerging research field in the context of innovation systems, where focus is put in the needs and advantages of involving users in the innovation creation and development process, as privilege sources of practical information on market needs and gaps. A key issue in this approach to innovation models is how products may be transferred from users to industry. Entrepreneurship may be a way to this question.

On the Sustainable Development of Solar Thermal Obligations in. Buildings in the Framework of the Portuguese Case

M. Lopes Prates, J. Cruz Costa, J. Farinha Mendes e Maria Joao Carvalho

INETI, Department of Renewable Energies, Campus do Lumiar do INETI, 1649-038 Lisboa, Portugal

Phone: +351 21 092 4769
Corresponding author, lopes. prates@ineti. pt

Abstract

This paper starts remembering the steps given in Portugal to prepare the introduction of a solar thermal obligation. Next, it presents a description of the present legislation related to the Solar Thermal Obligation (STO) and to other incentive measures for growth of the solar thermal market in Portugal. The main problems with implementation of the new regulation are analysed and systematized. Based on the acquired knowledge, further actions are presented to guarantee the success of Solar Thermal Obligation, namely proposals for updating the obligation in conformity with best practice for solar thermal installations and taking into account the new realities upcoming from the actual solar thermal market development, without sacrificing the final technical quality and user satisfaction.

Keywords: thermal performance of buildings, solar thermal obligation, solar thermal systems, solar thermal collectors, certification

1. Introduction

The first steps that allowed the present implementation of a solar thermal obligation in Portugal started in the past nineties, with the implementation of courses for installers of solar thermal systems and dissemination campaigns for good practices, in the framework of European ALTENER projects [1, 2], contributing to the development of education material to be used in installers training courses and to the establishment of the Portuguese qualification scheme for installers.

The next steps were given within the Sub Programme “Solar Hot Water for Portugal”, which was part of the general energy policy of the Portuguese Government, published in 2001[3]:

i) the implementation of a new Technical Committee on Energy, within the Portuguese Professional Certification System, that prepared and implemented a scheme for solar systems installers based on what was developed by QUALISOL project [2];

ii) the definition of a certification scheme for solar thermal collectors and factory made solar thermal systems.

In 2002, the rules of the “Incentive Measures for Renewable Energies and Rational Use of Energy” [4], applied the two certification schemes to Guarantee the Quality of Solar Thermal Systems to which the Incentives were applicable [5].

In 2006, the legislation transposing the EU Directive 2002/91/CE (EPBD) [6] was concluded and this was the final step for the implementation of a first solar thermal obligation in Portugal. This obligation is integrated in the new Portuguese Thermal Performance Building Regulation (RCCTE) [7].

Master Degree on Energy and Environment Engineering

The Integrated Master’s degree on Energy and Environment Engineering is a 5 year program that graduates professionals with capacity of intervention in the areas of renewable energies, energy efficiency, and mitigation of the environmental impacts of conventional energy production technologies. Conclusion of the first three years of the program (180 ECTS) gives the student a Bachelor’s Degree in Engineering Sciences, with specificity in Energy and Environment. Although this graduation degree allows for a straight access to the labour market, it is mainly a mobility

diploma, permitting to apply for second cycles (Master’s degrees), namely, in other Engineering areas. Reciprocally, the 4th year of the course provides an access point for students with other first cycle backgrounds.

The first three years of the Master program are similar to any other mainstream Engineering programs, like Mechanical, Electrical or Electronic Engineering, but include a few “flavour” short courses like, for instance, “Earth, Environment and Climate”, “Energy Sustainability”, “Climate Change”, or “Solar Radiation and Energy”. During the first three semesters of the last two years, the students attend 6_ECTS mandatory courses on “Energy Efficiency”, “Electrical Distribution Networks”, “Combustion Technologies”, “Energy and Environment”, “Climate Changes and Emission Trading”, “Hydrogen and New Energy Vectors” and “International Energy and Environment Law”. During this period the students also attend six 6ECTS optional courses to be chosen from the following group: “Photovoltaic Energy”, “Solar Thermal Energy”, “Wind Energy”, “Heat Transfer in Buildings”, “Energy Systems in Buildings”, “Geothermal Energy”, “Biomass Energy” and “Ocean Energy”. Two of the six optional courses can be substituted by professional activity in a relevant area for the Master program.

The Master’s course is organized by the Department of Geographic Engineering, Geophysics and Energy (DEGGE), a teaching and research unit of the Faculty of Science of the University of Lisbon, with competences in the areas of Geophysics, Geographical Information Systems and Renewable Energies, in particular, Solar Photovoltaic and Energy in Buildings. Teaching is further supported by research developed by the following groups: SESUL-Centre for Sustainable Energy Systems of the University of Lisbon (http://sesul. fc. ul. pt/), CGUL-Centre of Geophysics of the University of Lisbon (http://www. igidl. ul. pt/), the Department of Renewable Energies (DER — http://www. ineti. pt/uo/uo/7uoM43) and the Department of Energy Engineering and Environmental Control (DEECA — http://www. ineti. pt/uo/uo/7uoM41) of INETI.

Since the first graduations will take place by the end of the 2008/09 academic year, information about the acceptance of these students by the labour market isn’t yet available. However, a significant number of successful summer internships in companies were carried out this year by the most advanced students. The result of these first contacts seem to be positive, since the companies involved are now clearly open to maintain the contact with these students, creating an opportunity for them to develop their Master Thesis in a company environment.

Moreover, the foreseen growth of the renewable energy industry in Europe, such as estimates by the European Renewable Energy Council, forecasts that that by 2010 their will be about 1 million jobs in the area of the renewable energies, and doubling by 2020. In order to ease integration in the labour market of recently formed students, connections with leading companies in the areas of this Master’s degree are being actively promoted.

Training of Trainers

In order to produce trainers who have technical dept as well as an appreciation for the poor rural peoples need for cost effective energy supply, the Project designed a series of training modules to include intensive hands-on activities on the design, installation and trouble shooting of PV systems and solar hot water systems and solar cookers. A manual for training technicians on the installation, maintenance and operation of photovoltaic systems and another on passive solar for

home applications were developed. A course based on these manuals was delivered to EMU faculty and a cadre of educators involved in technical and vocational training through out the country. CARITAS led the process for selecting participants and ensured substantial, if not dominant, women representation. This course ran for two weeks and have been delivered many times. It was based on a model that had been successfully used by REFAD in Southern Africa and the Carrebean. Participants’ kits will include both laboratory manuals and lecture notes that could be used for training technicians. Training of Technicians approach has been proven to be a cost effective model for building a large capacity of competent solar energy equipment technicians in developing economies.

Review of an International Master Programme in Solar Energy Engineering

E. Lindberg*, F. Fiedler, C. Bales, M. Ronnelid

Solar Energy Research Center SERC, Dalarna University College, 78188 Borlange, Sweden

Подпись: *Corresponding Author, eli@du. se

Abstract

The European Solar Engineering School ESES is a one-year master programme that started in 1999 at the Solar Energy Research Center, SERC, Dalarna University College. The programme, run in English, consists of courses which cover passive and active solar thermal, solar energy for tropical climates, PV and PV/Hybrid system design, and have sections on topics such as economy and social aspects as well as other renewable energy sources. ESES is then finished with a research project as thesis work. Over the years the contents have been evolved and improved, and new experimental work has been introduced.

The programme has been growing in popularity over the years, with over 20 students each year. Approximately half of the students come from Europe, the rest coming from all over the globe. This paper describes the contents and experiences from eight years of running the programme. The majority of the students from ESES have found work in the solar industry, energy industry or taken up PhD positions. An alumni group has been started that actively gives support to past, present and potential future students.

Keywords: Solar education, master’s programme

1. Introduction

Nowadays it is widely accepted among scientists and common people that direct solar energy is an important energy source which will contribute in gradually replacing non-renewable sources of energy. In this process, university trained engineers play a crucial role. It is therefore necessary that these young women and men get a good understanding and comprehensive knowledge of renewable energy technology.

In 1996 the formation of European Solar Engineering School ESES was proposed, in which students from all over Europe could receive appropriate training (1). Such a school should preferably be placed somewhere in Europe where the climate is stable, with clear skies during most of the year, so laboratory work and hands-on experience could be regular parts of the curricula. An ESES Initiative Group was formed in 1997, and ESES was started at the Solar Energy Research Center SERC, Dalarna University College, in Borlange (Sweden) until another suitable site could be found. This site has not been found, and in fact the search has been stopped as the programme has been found to work well in its current form and location.

During the summers of 1998 and 1999 the first trial courses in solar thermal and photovoltaic engineering were given. In autumn 1998, a curriculum for a one-year master level programme in solar energy engineering was sanctioned by the University’s Educational Board. In autumn 2007 a completely restructured one-year programme started.

The number of students has slowly increased over the years from a modest 6 students in the first full year to over 20 students in the last years. The students come from a wide range of countries from around the world.

Not all students intend to study the whole programme. They may choose single courses as part of studies in other programmes or are interested in getting knowledge in a specific field i. e. photovoltaics. Many students are exchange students in partnership with other universities, for example the Erasmus programme.

Expected project results

Quantitative results;

• Centres for measuring the solar energy that can be collected from tilted surfaces (unique in Romania);

• Modernization and installation, by applying the project’s energy concepts, at the terrace of West University of Timisoara, and at a terrace of the University of Architecture and Urban Planning “Ion Mincu” — Bucharest; Solar windows in The BIPV Laboratory from Polytechnic University of Bucharest

• Project website, containing: software and guide, accessible online, for: estimation of the solar energy that can be collected from tilted surfaces; PV system design; architectural solutions;

• Database containing measurements of solar energy collectable from tilted surfaces;

• Submission to the authorities of the legal requirements related to the authorisation of the operation of distributed electric power sources;

• Organisation of a thematic competition („Solar house”) for students;

• Organisation of workshop for discussing the results of the project with representatives of the target groups;

• Brochures, guidelines, bibliographies for the different target groups Estimated profits and profitableness:

• Development of specialisation, in the solar architecture with great opportunities within EU market;

• Achievement of important steps in the development of the photovoltaic industry in Romania;

• Possibility of capitalization on the results obtained by the project in Romania’s neighbouring countries;

• Achievement of important steps in fulfilling Romania’s commitments as future member of the EU, as regards Chapters Environment and Energy.

Dissemination plan:

Logical Diagram of the project dissemination activities is presented in Fig. 1. Main points of this dissemination plan are considered to be the following:

• Organisation the visiting of the demo PV installations for interested public;

• Promoting the idea of solar architecture to the specialists, both through the web-site and through roundtables, conferences and colloquiums addressed to both local authorities and the large public. Editing a Newsletter for presenting the results of the project and elaboration of brochures for dissemination to the large public;

• Creation and administration of a specialised website dedicated to all project activities. The website will include two sections, one public (including users form the EU states) and one for the partners’ use;

• Organisation of a workshop on aspects related to solar radiation measuring on tilted surfaces;

• Organisation of a competition of projects/models of “Solar houses” for students of architecture and engineering universities;

• Elaboration of a guide on BIPV systems and on the new technologies, for architects, and of materials for building daylighting as well as a bibliography for specialists;

■ Presentation of the results of the project at national and European scientific events;

Подпись: Fig. 1. Logical diagram of the project development -dissemination activities

• Participation (by models and posters) to national exhibitions specialized in building construction: Constructexpo and Windoor.

Procedure to identify heat and power plants in the CIS

To gather information about the heat and power plants the following methods have been used:

• internet search at the website of the plant operator

• contact via fax and e-mail (with a special questionnaire)

• telephone calls

• pictures of the plants via Google Earth

• in some cases also on site visits

For a general overview of the existing heat and power plants, an internet search was carried out. This proved to be very effective because almost all heat and power plant operators have web sites[2]. Some technical parameters like installed power and heat capacity or produced energy can also be found in the internet. However, no information about the district heating net hydraulics (open, closed or mix systems), flow rate of cold water to be refilled, temperature level or operation mode can be obtained in this way. Thus, internet search alone does not provide sufficient information for an evaluation.

In a second step, heat and power plant operators were contacted via fax or mail with a special questionnaire about technical parameters. Unfortunately, but not completely surprising, no email or fax has been answered. With a telephone survey it was possible to obtain further technical information (like net hydraulic and summer operation) about the heat and power plant and district heating net. In general, it was unlikely to get information about the cold water flow rate, operation mode and energy generation or fuel costs.

Additionally, Google Earth was used to estimate the available area for installation of uncovered collectors. However, in all cases an on-site visit was found to be inevitable in order to gather all data required for a full evaluation. Figure 2 shows a comparison of the data collection methods used with regard to the data obtained.

location

X

X

X

net hydraulic (open / closed / mix)

X

(X)

X

summer operation (yes/no)

(X)

(X)

installed power and thermal capacity

X

(X)

(X)

fresh water flow rate and inlet temperature

(X)

X

available areas for uncovered collector

X

X

used fuels

(X)

(X)

X

costs (fuels, heat costs, etc.)

(X)

X

(X)

Fig. 2. Comparison of methods to collect information about heat and power plants in CIS

Photovoltaic System

The PV is sized according with the electric final energy demand, shown in Table 4. For each user/solar thermal scenario we have different electricity demand and consequently different PV areas. The reference PV system considered in this study has a total efficiency of 10.7%, with south facing panels, 35 ° inclination. The yearly production of the PV is 1363 Wh/Wp installed. The PV system is connected to the supply grid, without the support of any store devices. When there is a surplus on the production, the excess electricity is injected into the grid, if the electricity produced on-site is not enough to meet demand, electricity is purchased from the grid.

3. Results

Table 4 and 5 show the total energy electrical energy demand and the system characteristics for the twenty scenarios considered. As previous addressed in section 4, the difference between the groups BAU and BEST is electrical appliance efficiency and usage patterns.

BEST

BAU

ST Area/Vr |m2]/[l]

Heating

[kWh/yr]

Cooling

[kWh/yrJ

Aux.

Support

[kWh/yr]

Elec.

Appliances

[kWh/yr]

Electric

Final

Energy

[kWh/yr]

Aux.

Support

[kWh/yr]

Elec.

Appliances

[kWh/yr]

Electric

Final

Energy

[kWh/yr]

4/300

71

1179

1982

54

2982

3767

5/400

25

1179

1936

18

2982

3732

6/500

654

10

1179

1921

6

2982

3720

7/600

4

1179

1914

2

2982

3716

8/700

78

2

1179

1912

2

2982

3715

4/300

604

1179

1861

568

2982

3628

5/400

409

1179

1665

379

2982

3439

6/500

284

1179

1541

260

2982

3320

7/500

219

1179

1476

200

2982

3260

8/700

146

1179

1403

129

2982

3189

Table 5. Minimum PV areas needed to supply the different electricity demands (Total columns in Table 3). ST Area is the solar thermal panels area and the Vr is the volume of the ST reservoir.

ST Area/Vr |m2]/[l]

BEST

BAU

PV Areas [m!|

kWp

PV Areas [m1]

kWp

4/300

10.1

1.45

19.1

2.76

5/400

9.8

1.42

18.9

2.74

6/500

9.7

1.41

18.9

2.73

7/600

9.7

1.40

18.8

2.73

8/700

9.7

1.40

18.8

2.73

4/300

9.4

1.37

18.4

2.66

5/400

8.4

1.22

17.4

2.52

6/500

7.8

1.13

16.8

2.44

7/500

7.5

1.08

16.5

2.39

8/700

7.1

1.03

16.2

2.34

As expected, when the ST heats the house, less PV is required, as shown in table 5.

4. Financial Analysis

To estimate the initial investment cost for renewable energy systems we considered a cost of 700€/m2 for solar thermal system and 5€/Wp for the PV [8]. In the BEST group case we also accounted for an extra cost of 250€ for each machine of class A, for total of 750€ for the three machines.

Renewables reduce the house final electricity net yearly demand and costs to zero. The 10 year simple net cost is based on a house with the same envelope, but without renewables or efficient appliances. The 10 years cumulative cost of the electricity is deducted from the initial investment cost, see table 7.

Cooling

Elec. Appliances

Heating

DHW

Electric Final Energy

[kWh/yr]

[kWh/yr]

[kWh/yr]

[kWh/yr]

[kWh/yr]

78

2982

654

1422

5136

For the 10 years cost two scenarios were considered: 0.1€/kWh that is the price of electricity in Portugal and 0.2€/kWh, a conservative estimate of the “real ” price of electricity if it had followed the price rises of oil during the last years [9].

Table 7. Initial investment costs, IC, and 10 years simple net cost for electricity prices of 0.1€/kWh and

0.2€/kWh.

BEST

BAU

ST Area/Vr [m3]/|l|

IC[€]

10 years Simple Net Cost ‘ [€]

IC €]

10 years Simple Net Cost ‘ [€]

0.1 €/kWh

0.2 €/kWh

0.1 €/kWh

0.2 €/kWh

4/300

10820

5684

547

16620

11484

6348

5/400

11351

6215

1079

17189

12053

6917

6/500

11997

6861

1724

17847

12711

7574

7/600

12672

7536

2400

18530

13394

8258

8/700

13364

8228

3092

19229

14093

8957

4/300

10377

5240

104

16109

10973

5837

5/400

10359

5223

87

16117

10981

5845

6/500

10603

5467

331

16380

11244

6107

7/500

11063

5927

791

16858

11721

6585

8/700

11495

6359

1223

17299

12163

7026

The Portuguese micro-generation law [10] gives the possibility to sell PV electricity at a subsidized price. The difference between the purchase and the subsidized price of electricity works as a financial incentive to the implementation of micro-generation. To estimate the 10 years simple net cost for the subsidized scenario we deducted from the initial investment cost, the cost of electricity that we had to buy during those 10 years, if the house didn’t have any renewable sources available, see Table 6 (price of 0.1€/kWh). In addition we also deducted the PV electricity that was not consumed in the house at the price of the difference between the purchase and the subsidized price (0.1-0.5€/kWh).

Table 8. 10 years simple net cost for purchased electricity (0.1€/kWh) and subsidized sale

price(0.5€/kWh).

ST Area/Vr [m2]/[l]

BEST

BAU

Sale/Buy

[kWh/yr]

Subsidized lOyears [€]

Subsidized Payback [yr]

Sale/Buy

[kWh/yrJ

Subsidized lOyears [€J

Subsidized Payback [yrj

4/300

1725

-1218

9.0

3374

-2013

8.9

5/400

1690

-546

9.5

3353

-1358

9.3

6/500

1679

145

10.1

3344

-664

9.6

7/600

1673

843

10.7

3339

36

10.0

8/700

1728

1315

11.1

3364

637

10.3

4/300

1619

-1234

8.9

3192

-1795

9.0

5/400

1470

-656

9.4

3060

-1259

9.3

6/500

1375

-31

10.0

2978

-668

9.6

7/500

1321

644

10.6

2929

5

10.0

8/700

1260

1321

11.3

2873

669

10.4

5. Conclusions

As can be seen in Table 3 from energy saving and financial perspective the best option is a house heated by the ST system with 5m2 of panel and a reservoir of 400l. Since the electrical appliances represent by far the biggest share of final energy use, for the same solar thermal configuration the BEST group always performed considerably better.

The cost and performance of the NZEB system shows low sensitivity to the size of the ST, whenever solar hot water is used to its maximum, with the best cases occurring in a wide range of panel areas: 4-8m2. In this case, the total panel (ST+PV) area is approximately constant (15m2). Clearly the infinite reservoir that the PV system has (the grid) in conjunction with the mismatch between demand and supply of the ST systems (less heat provided in winter) even the “competition” between the two systems in our NZEB scenario.

However in the subsidized micro generation scenario significant changes occur; the best scenarios are the ones where more final energy is used. This is a direct consequence of the NZEB approach, where increased energy consumption leads to more PV, and consequently more electricity sold to the grid. Clearly, if feasible, the micro generation scheme should have a variable rate, with higher rewards for the most energy efficient consumers (in our case the “BEST” consumer scenario).

Overall the results are encouraging, it is possible to make an NZEB single family house with an investment payback of ten years or less. The initial investment is approximately 100€/m2 (5-10% of the typical total house price).

6. References

[1] Green paper — Facts sheet: A European Strategy for Sustainable, Competitive and Secure Energy, Commission of the European Communities, Brussels, 8.3.2006

[2] European Energy and Transports — trends to 2030, European Commission, Office for Official Publications of the European Communities, Luxembourg, 2003

[3] Karsten Voss; keynote: “ Net Zero Energy Buildings”; University Wuppertal; Building Physics and Technical Building Service; Zero Energy Buildings — IEA SHCP task definition Workshop, Washington DC, USA, January 2008.

[4] Paredes, P. — "Aplicagao a uma casa unifamiliar", Optimizagao Energetica nos edificios, 2006 , Portugal.

[5] Carrilho da Graga, G.; Lerer, Maria M. and Paredes, Pedro C. — WP 2, System and Component Characterisation REPORT — Passive House, NaturalWorks, 2006, Portugal.

[6] EnergyPlus, Version 2.1, October 2007.

[7] Report: “Eficiencia energetica em equipamentos e sistemas electricos no sector residential”; Portuguese ministry of economy, April 2004. [13] [14] [15]