J. Maia Alves1*, Joao M. Serra1, Miguel C. Brito1, Guilherme Carrilho da Gra^a1, Pierre
Hollmuller1, Killian Lobato1, Antonio Vallera1, Antonio Joyce2 and Isabel Cabrita3

1 University of Lisbon, Faculty of Sciences,

Department of Geographical Engineering, Geophysics and Energy
2 INETI, Department of Renewable Energies, Lisbon, Portugal
3 INETI, Department of Energy Engineering and Environmental Control, Lisbon, Portugal

*jma@fc. ul. pt

Abstract

Since the academic year of 2006/07 the University of Lisbon offers a 5-year Integrated Master Degree on Energy and Environment Engineering. The University of Lisbon is also one of the Portuguese Universities involved on the MIT-Portugal Program, in particular in the area of Sustainable Energy Systems. In this context, a Doctoral Program and Diploma of Advanced Studies were created in the academic year of 2007/08. This set of Sustainable Energy Systems Studies at the University of Lisbon, and the connected research activity, are both shortly presented.

Keywords: Renewable Energy Education

1. Introduction

In the academic year of 2004/05 the University of Lisbon started a 4-year graduation course on Energy and Environment at the Faculty of Sciences. This course, with a strong renewable energy flavour, was launched in close cooperation with the National Institute of Engineering, Technology and Innovation (INETI) involving the Renewable Energy and the Energy Engineering & Environmental Control departments of this institution. This graduation course was adapted to the Bologna process during the academic year of 2006/07, as a 5-year Integrated Master Degree on Energy and Environment Engineering which is currently attracting a significant number of good students, both in the first and in the fourth years (1st and 2nd cycles respectively). The first students are expected to finish this Master Degree in the academic year of 2008/09.

To complete a coherent set of programs in this area, the University of Lisbon launched a Doctoral Program and Diploma in Advanced Studies in the area of Sustainable Energy Systems in the academic year of 2007/08. This was done in the context of the MIT-Portugal Program.

1.1. Curriculum design

Based on the findings provided by the needs analysis, the in-service teachers’ training course curriculum, as presented in Table 1, was designed.

The sustainability concept was considered in the curriculum: technical dimension — specific modules related to renewable energy systems; ecological dimension — modules related to environment (pollution/protection, monitoring and management), and also to wastes management; cultural dimension — modules related to novel teaching methods and to the didactics required by the implementation of the subject of renewable energy in the school curriculum, also the applied English language was proposed, considering that the teachers are not native English speakers.

At the same time, the course materials were developed by the partners in the project, according to a general structure of the syllabi agreed in the partnership. Thus, it is considered that the in-service training course has a deep international character, combining the experience in different countries, and different positions in the socio-economic system.

In the Transilvania University and also in the College for Natural Sciences, sets of training kits were developed this representing important output of the SEE EU Tool project. The kits are intended to be used by student-teachers during the in-service training course, but also during the instructional activity.

The collector area is a useful figure for the solar thermal experts, but it cannot be compared with the installed capacity in other fields. Therefore the IEA Solar Heating and Cooling programme, Estif and other trade associations have adopted a value of 0,7 kw/m2 as average capacity [10]. This conversion factor has been adopted by the IEA statistics department. Eurostat is considering using the same factor for their statistics. The installed collector capacity can now be compared with other technologies [9].

1.2. Monitoring of the solar thermal production

The total thermal production is in general calculated from the installed collector area. Most countries use a simple figure per square meter of collector. The IEA Solar Heating and Cooling programme has a more sophisticated method that includes the simulation of a typical solar system for each country [9]. Eurostat takes over the figures from the statistical offices in the EU-countries. They ask for the collector input as in their definition in the input-method. This is the energy falling on the collector minus the collector losses. Most countries seem to use a figure that is available in their country. In table 1 it can be seen that there is significant difference in the production per

square meter of collector. It varies from 64 to 903 kwh/m2 [8]. This difference cannot be explained by the difference in insolation or quality of the solar collector systems.

The ThERRA project is proposing a fixed method for calculating the collector production, based on measured data. If no measured data are available a default value can be used.

In the benchmark report of the methodology the difference with the current methods is found [11].

2.4.1 Relationships between sunshine availability and affectivity, stress and well-being

Further to the last comment above, it is interesting initially to test a very simple relationship — positive and negative affectivity scores (with mean averages from 1-5) as a function of the percentage of glass to living room floor area — see Fig.1; where high to low rank order of ratios is: solar tower (41.6%), quasi-solar low-rise (27.9%), solar medium-rise (25%), non­solar medium-rise (19.6%) and non-solar tower (13.7%). It should also be born in mind that the sample size for the solar and non-solar towers was respectively 16 and 12; 9 in the non­solar medium-rise block and 11 in the low-rise quasi-solar scheme; but only 2 in the solar medium-rise case. Therefore, one might reasonably have expected its graphical position to be out of kilter with other case studies, if, indeed, one could justify expectation of any logical correlation. However, this has not proved to be the case. It conforms to a distinct straight-line developing into a steep curve on the positive side, and a generally steeper curve on the negative side. The rate of steepness expresses the diminishing linkage between window size and affectivity. On the positive side, it looks as if this may occur above the 25% mark on the y-axis; while the negative side appears less defined. It may also be noted that a follow-up interview with a smaller sample (7 rather than 11) in the case of the medium-rise non-solar block, with the negative affectivity questions halved from 10 to 5, increased negativity to value of 1.51, rather than 1.25. Although this lies closer to an idealised curve, the smaller number of questions and respondents also give an indication of variability according to sample size. Similarly, with positive affectivity responses bundled down to 3 from10, the score increases to 4.14 from 3.60; in this case suggesting a steadier upward curve. In any event, although the relationships might seem overly simplistic, the results do support a

general trend for increasing positive affectivity with increasing window aperture, as well as a possible corresponding decrease in negative affectivity.

The value given to sunlight access, and its added motivational effect, together with private and communal outdoor space is summarized in Table 1. The ratings correspond reasonably well with affectivity, although some responses may reflect what is available and others what would desirably be available. It is certainly evident that respondents with good access to sunlight and access to suitable private outdoor space valued the amenity afforded.

Table 1. Value of sunshine access and private and communal outdoor space

There are less clear tendencies for ‘perceived stress’ relative to solar and non-solar case studies. However, there is a clear-cut difference between the two towers — 1.24 mean score for the solar one compared with 1.88 for non-solar. The mode (most frequent score) for the solar tower was also very clearly 1.0 (signifying no perceived stress), with 13 out of 16 households scoring this way. However, both the solar and non-solar medium rise blocks also scored 1.0; and the quasi-solar reference blocks also scored low at 1.20, with 1.0 again the clear mode.

As anticipated, any relationship between well-being scores and sunshine is not evident, even though the solar tower had the lowest score of 1.57; the others being: 1.94 for the non-solar tower; 2.47 for the solar medium-rise block (small sample); 2.7 for the non-solar, medium — rise block (elderly residents); and 2.01 for the quasi-solar, low-rise blocks (elderly residents).

2.4.2 Relationships between sunshine availability and physical environmental conditions

It is generally accepted that factors such as intensity of occupancy are relevant to environmental outcomes such as indoor temperature and humidity. Social habits such as smoking are also known to influence ventilation regimes [7], but is fairly evenly spread among case studies. Table 2 summarizes the estimates of intensity of occupancy in person — hours per m3 volume.

Table 3 then gives mean, maximum and minimum temperatures and relative humidity (RH) in different seasons for spot readings taken in sets of living rooms and main bedrooms in each

case; while Table 4 gives the equivalent values for CO2 for different seasons, whichever is the greatest. The modest differences between solar and non-solar models in terms of temperature and relative humidity are noteworthy, suggesting that despite significant differences in terms of energy efficiency and energy costs most respondents were able to heat to a reasonable level.

Data in Table 4 indicate that the solar tower enjoys better air quality than the non-solar tower; and that the solar medium-rise block enjoys better air quality than the non-solar medium-rise block. There is also similarity comparing the values for the non-solar tower and the non-solar medium-rise block. Here only the minimum values fall within the range normally regarded as acceptable; the maxima are well above the threshold taken as the tolerable maximum; and the mean values are somewhat above this threshold. In the solar tower only three of sixteen flats came above this limit in their living rooms in the case of winter readings. In the case of the solar medium-rise block, the sample was too small to pass a similar comment — one of the two tenants came above the 1,000 ppm limit. This appears noteworthy given the presence of

the MVHR system. However, it was revealed during the interview that the occupant avoided using the MVHR due to a phobia about insects entering via the ducts. It is also worth noting that the CO2 readings for the quasi-solar low-rise were similar to those of the tower block. Given the respective similarities between the solar tower sample and the quasi-solar low-rise sample with respect to positive affectivity (4.42 cf. 4.67) and perceived stress (1.24 cf.1.20 with 1.0 the mode in each case), taken together with general level of energy efficiency (see

2.1 and 2.3 above) and solar access (Fig. 1), it is reasonable to posit that this may engender a fairly relaxed attitude to opening windows.

It is also of interest to note that the average temperature regimes in the solar and non-solar towers appear quite similar, as does RH; while comparing respective medium rise blocks, both RH and temperature are somewhat higher in the solar case. Durational readings, Table 5, provide a more in-depth picture of temperature and humidity, although the sample is limited.

The last two rows in Table 5 are of particular significance. Although RH seems to be mainly within a reasonable range, the percentage frequency of mixing ratio of dry to moist air (MR) values above the threshold of 7 g/kg is worryingly high in the non-solar cases; especially given that there are still significant percentages above 10 g/kg. The threshold or benchmark value is used because this is the level above which it has been found that the dust mite population will readily grow [8]. The lower levels of frequency in this regard for the solar cases correspond with the better air quality. Further, it is relevant that the higher levels of ‘intensity of occupation’ (Table 2) in the non-solar cases correspond with the poorer air quality (Table 4) and higher frequency of humidity (mixing ratio) above ‘growing threshold’ for dust mites (Table 5). Table 6 summarizes presence of dampness due to condensation and/or presence of mould. Again, the non-solar housing is manifestly at a disadvantage compared with the solar, or even quasi-solar counterparts.

It is also likely that the ones with relatively high incidence of condensation and/or mould will have expressed their dissatisfaction via negative affectivity and/or perceived stress. Links to poor health or well-being are also a possibility, especially relative to the responses to questions concerning nasal ailments (33% for the non-solar tower cf. 12.5% for the solar tower).

3. Conclusions

Firstly, the analysis does support an apparent association between sunlight/energy-efficiency attributes and perceived stress and positive affectivity, particularly the latter where a logical connection could be anticipated due to questions being directed at positive emotions. For the converse reason, an association between sunlight and negative affectivity is less convincing. Causality relating to health/wellbeing is also so diverse that it was unlikely to yield any tangible association with access to sunlight. Having said that, the solar tower does have the lowest incidence of ailments. The responses relating to how much residents valued sunshine and were additionally motivated by its presence, as well as private outdoor space in the form of ‘sun-traps’, add further weight to this conclusion, aligning with the positive affectivity scores. Secondly, there is evidence of a relationship between availability of sunlight in homes and some physical environmental indicators: a) CO2, expressing air quality; b) humidity, when expressed as a percentage frequency above particular mixing ratio thresholds which in turn denote the likelihood of dust mite propagation and hence risk of asthma. The greater the solar access, the better was the air quality, and the lower were the levels of mixing ratio (MR) or vapour pressure.

Furthermore, the presence of damp or mould was greater in the non-solar case studies. Although, one might have expected such incidence to relate to general energy-efficiency and the ability to heat dwellings, there were no examples of unsuitably low temperatures during any of the periods used for monitoring (mainly winter and spring, but also some in autumn). Instead, the explanation appears to be that the more energy-efficient, and also more sunlit, homes encourage residents to be more relaxed in relation to ventilation — i. e. more inclined to open windows. It is also apparent that they are able to do this without unduly compromising economy — the solar case studies are also the cheapest to heat. It also seems likely that thermal capacity is relevant in playing a part in allowing intermittent opening of windows, without any undue energy penalty.

The evidence presented is such that the basic hypothesis appears to merit further detailed investigation. Environmental architects and engineers have for too long only been evaluating passive solar design in terms of potential energy saving rather than psychosocial benefits, that are in turn linked to wider ‘quality of life’ environmental and sustainability indicators.

References

[1] Downes A and Blunt T P, (1877). Researches on the effect of light upon bacteria and other organisms, Proceedings of the Royal Society, 26, 488-500.

[2] Garrod L P, (1944). Some observations on hospital dust with special reference to light as a hygienic safeguard, British Medical Journal Feb. 19, 245-257.

[3] Walsh et al, (2005). The effect of sunlight on postoperative medication use: a prospective study of patients undergoing spinal surgery, Psychosomatic Medicine, 67, 156-163.

[4] Beauchmenin K M and Hays P, (1996). Sunny rooms expedite recovery from severe and refractory depressions, Journal of Affective Disorders, 40, 49-51.

[5] Beauchmenin K M and Hays P, (1998). Dying in the dark: sunshine, gender and outcomes in myocardial infarction, Journal of the Royal Society of Medicine, 91, July, 352-354.

[6] Gibson J J, (1966). The Senses Considered as Perceptual Systems, Greenwood Press, USA.

[7] Ho H M, (1995). User-performance sensitivity of small sunspaces in a Scottish housing context, PhD Thesis, Mackintosh School of Architecture, University of Glasgow, UK

[8] Platts-Mills T and De Weck A, (1989). Dust mite allergens and asthma — a worldwide problem. In: Journal of Allergy and Clinical Immunology, (83), 416-427.

Masters courses are to be introduced at the three African Universities in the PREA project for capacity building in education and training and to promote sustainability concepts in the design, construction and occupancy of buildings. The long term target is to train academicians for more research and further propagation of these ideas and concepts in subsequent courses even after the end of the project’s scheduled time of three years. The aim is to eventually spread these ideas and concepts throughout the entire continent, by cooperation of the three African Universities and by networking with other African institutions engaged in this area.

The masters courses are supposed to use the expertise gained on a similar project in Europe called TAREB (Teaching about Renewable Energy in Buildings) but will be tailored to suit the local environment and to reflect specific demands of the country in which they are offered and taught as well as the technologies that can be easily made available there. The Masters programs will generally have some compulsory core modules and optional specialist modules some of which will be tailored to reflect local demands.

At Uganda Martyrs University, the Masters’ course is planned to be introduced in phases step by step. According to Mark Olweny, the assistant Dean of Faculty of Building and Technology, who is also the local PREA project coordinator there, the project would be phased in, in two steps starting with a Graduate Diploma in Environmental Design to run either as a one year full-time course or as a two year part-time course. The part-time program, 50% of which can be taken in form of off-campus modules, is to be aimed at applicants possessing the equivalent of the basic three-year undergraduate program currently run by the same University as Bachelor of Science in Building Design and Technology (B. Sc. BDT). The second phase will be the actual Masters program will be called Master of Environmental Design (M. Sc. ED). It will consist of specialist modules and will be aimed at professionals who have either completed the full five years Bachelor of Architecture course or have upgraded their basic three year course with the Graduate Diploma. Some people with other professional qualifications e. g. in Engineering, Urban Design or Quantity Surveying will also be eligible to apply directly for the one year full-time Masters. Basic concepts in environmental design, will already have been introduced at undergraduate level, will develop students’ interest in this area and serve as a “catchment area” for students and professionals.

The new Masters course at Witwatersrand University (WITS) will aim at both students and professionals. According to plans already under way at WITS, the Masters course will be associated with four separate postgraduate activities namely organization of short open certificate courses and modules in collaboration with other institutions such as Stellenbosch University, establishing new “Continuing Professional Development” (CPD) courses for established professionals, incorporation of Energy Efficiency and Renewable Energy research into existing Masters and PhD work by research and thesis, as well as introduction of taught modules into Bachelor of Architectural Sciences (BAS(HONS)). There will be two masters versions namely the Professional Masters of Architecture (M. ARCH(PROF)) and the Master of Architecture specializing in Housing (M. ARCH(HOUS)). As an unexpected opportunity the PREA project coordinator at WITS, Daniel Irurah, was requested to develop a teaching module on Renewable Energy, in the process of establishing of a new Master of Philosophy (M. Phil) on Renewable Energy due to start at Stellenbosch University later this year (July

2007). PREA has been identified as one of the key strengths of WITS in its collaboration efforts with other institutions in South Africa.

Dar es Salaam University has established in co-operation with Ardhi University, Dar es Salaam, the new Master course “Renewable Energy”, which will start for the first time in September 2008. It has all the necessary manpower and teaching facilities for the course to be able to take off this year. Existing departments which are ready to collaborate in establishing the new Masters course include from University of Dar es Salaam Faculty of Civil Engineering and the Built Environment, the Department of Energy in the Faculty of Mechanical Engineering and Chemical Engineering and the Department of Electrical Power in the Faculty of Electrical Engineering and Information Technology and from Ardhi University Department of Architecture in the Faculty of Architecture and Planning (FAP).

2. Results / Discussion

After 30 months of the three-year-project have passed there could be reached most of the targets and many things were achieved that would not have happened without PREA:

• Initially three universities in sub-Saharan Africa have decided to implement masters courses in the area of renewable energies energy and energy efficient buildings during the project duration. Meanwhile the number of universities has increased to 5 by Ardhi University joining University of Dar es Salaam, and Sustainability Institute from Stellenbosch University joining Witwatersrand University.

• Six workshops about sustainable energy supply and about low cost and high comfort buildings have been carried out with active participation of key actors from the three African countries..

• The network of African institutions working in the areas of energy and building could be improved, last not least by the website www. ises. org/PREA.

Thus the PREA Project has already proved to be an important event in the development of energy consciousness in Africa. The response to the Workshops has been extremely good. The questionnaires given to both participants and organizers show, that people concerned are very satisfied with the stages and milestones that have been reached so far. Project websites (shown hereunder) have been established, Workshop handbooks with all the papers presented at Workshops have been published and distributed to workshop participants and other interested parties, a CD summarizing all activities has been developed and as requested by the European Commission, a PowerPoint presentation containing “publishable summary slides” has been produced and updated. The most important fact however is that through this PREA project, the issue of energy efficiency and renewable energy in buildings in Africa has obtained a forum through which it will be more specifically and efficiently addressed within an integrated building design and construction approach. Moreover, African universities have had a unique opportunity at South-South collaboration among each other and South — North collaboration with their European counterparts.

3. Conclusions

The PREA project, although scheduled to run for three years, is meant to have a long lasting impact in the development of a new energy consciousness in Africa. It has carried out six Workshops successfully, sensitizing African governments’ officials, policy makers, decision makers and implementers as well as regulatory agencies about the importance of energy efficiency and application of renewable energy technologies in buildings as a way of fighting poverty and at the same time

preserving the environment for posterity. In short the PREA project is a catalyst for sustainable development and poverty eradication in Africa. It will help Africa achieve some of the millennium development goals sooner rather than later. The implementation of the masters courses at the three African universities has started a sustainable development.

4. Acknowledgement

The European Union supported 50% of the PREA budget through their program Intelligent Energy Europe (IEE), subprogram. The German International Academic Exchange Service (DAAD) financially supported Dortmund University by matching funds. The other European partner universities and ISES, are meeting their share of the budget from their own resources. Contributions of the African University partners were realized in form of local organization of the seminars and arrangements for accommodating the Masters’ programs. The Development Bank of South Africa (DBSA), Johannesburg, and the Sustainability Institute, Stellenbosch University, kindly made their premises available for the South African Workshops.

References

Websites:

Websites associated with the PREA projects have been established by ISES and by the other project participant universities.

http://cms. ises. om/index. xsp

http://www. ises. org/PREA

http://www. bauwesen. tu-dortmund. de/ka/Homepage PREA/Deutsch/Home D/HOME PREA D. htm

http://hermes. wits. ac. za/www/Conferences/PREA-WITS

http://grbes. phys .uoa. gr/prea/index. htm

http://www. univ-lr. fr/poles/sciences/formations/gc/master afrique. html

http://www. sonnenseite. com/index. php? pageID=80&news:oid=n6416&svnlink:docID=&svnlink:linkI D=1&template=news detail. html

In order to estimate the auxiliary energy supplied by the heat pump to maintain the water inside the reservoir above 43°C, several reservoir volumes and ST areas were tested. We modeled the water temperature inside of the reservoir in each yearly simulation hourly time step, Ti, by using the following expression:

EHP — heat pump energy (< 43°C); ECoolmg — released energy to cool the reservoir (>80°C); Esolar — thermal solar energy collected; Eheatmg — house heating energy; EMHW — energy to heat the water for the washing machines (laundry and dishwasher); EMHW — losses through the reservoir surface; Vr — reservoir volume; Cp — water specific heat capacity; p — water density; Ti — reservoir water temperature.

The energy used to heat DWH is given by:

Edhw = p’ Cp • Vw (TDHW — Tw) (2)

VW — DHW volume; Cp — water specific heat capacity; p — water density; TDHW — domestic hot water temperature; Tw — water temperature from the tap.

The heat pump turns on if T i< 43°C. The heat pump energy demand is given by: eup = p4 Cp — v,. (Triin — y;.) (3)

Vr — reservoir volume; Cp — water specific heat capacity; p — water density; Tmin — reservoir water minimum temperature; Tj — reservoir water temperature.

If the water in the reservoir goes above 80°C (T > 80°C), heat is released in order to reduce the water temperature.

E0oo, ing=pCp-Vr{Ti-Tt^) (4)

Vr — reservoir volume; Cp — water specific heat capacity; p — water density; Tmax — reservoir water maximum temperature; Ti — reservoir water temperature.

Table 3 shows the use of the solar thermal system for the different scenarios. The first five scenarios the house is heated with the heat pump, in the last five is heated with solar thermal (the same division is used in tables 3, 4, 6 and 7).

The village power could also be used for water pumping to provide portable water for the village dwellers. This will cut down on the labor and time women spend to fetch water for drinking and other uses in their families thereby freeing up time for them to participate in learning and other social and economic empowerment activities. Training programs included a public workshop on household water and energy management to ensure energy and water use efficiency.

1.2. Training and Capacity Building Programs

The objective of these activities was to establish the human infrastructure necessary for a sustainable renewable energy industry for rural development. The partnership developed and delivered a number of specific training courses (and workshops and seminars) to specific audiences during this project, and paved the way for the development of other courses for future delivery as well as provide an impetus for policy discussions on women programs and other developmental initiatives. Training and workshop participants included locals.

One drawback with the study is that no consideration been taken to that fact that the Swedish electricity system today have a large part of non-interruptible power generation, i. e. electricity generation that not can be shut down when the sun shines. This concerns for example a part of the hydroelectric power generation, nuclear power and some industrial power generation. [3] has discussed this and calculated the non-adjustable power generation in Sweden to be 6,9 GW (July) — 12,7 GW (winter). Nuclear power stands for the largest part of this, varying from 4,9 GW (summer) to 9,4 GW (winter). No detailed calculation has been performed on how this will change the possibility for large scale solar electricity generation in Sweden, but a rough estimation is that this almost half the possible PV area that can be installed in Sweden without significant overproduction. It is obvious that a large share of non-adjustable nuclear power in the electricity mix has a negative impact on the possibility to large scale introduction of solar electricity in Sweden — at least when assuming the usage pattern as today and when the possibility to store electricity not is taken into account. This has to do with the very uneven access to solar irradiation over the year in Sweden, in combination that the electricity consumption is substantially lower during the summer at the same time as only half of the nuclear power plants in Sweden are shut down for yearly maintenance.

Since solar electricity is seen as one important, and probably necessary, large scale electricity source in the future it is important that we study future incorporation of solar electricity in the electricity grid thoroughly. For this, we should not be satisfied with how the usage profile looks like today, but should study how the usage profile could be changed to facilitate large scale solar electricity. It is also important to remember that other renewable energy sources like wind and wave power also are non-adjustable and all these energy sources have to be studied together. Although out of the main scope of this paper, some suggestions can be done how to increase the share of solar electricity in the future electrical system:

• Introducing movable (N-S tracking) PV technology will increase and even out the daily electricity production profile, and thereby increase the daily production period. It is important to remember that when PV becomes a large energy source in the grid, it is favourable to rather place stationary modules to south-east and south-west than to the south. In Sweden, south vertical PV modules give a higher winter output, although the annual performance is approx. 25% lower than a tilted module.

• The different electrical grids in different countries have to be coordinated to even out the electricity consumption, which will be favourable for solar electricity. The consumption profile in Sweden with much higher electricity usage during winter is for example very different from the consumption profile in more south countries in Europe and coordination of the different electrical grids should be favourable. ABB has developed the HVDC (High Voltage Direct Current) technology, which is used to transmit electric power over long distances with low electrical losses [4], and this makes remote production of solar electricity and connection of different grids

interesting. Countries like Sweden should not hesitate to invest in solar production technology in other countries with more even electricity production profile, like south of Europe or North Africa.

• Storage technology has to be further developed so it is possible to store energy from day to night or even during longer periods to extend the use of solar electricity. It is still questionable if small scale storage, like batteries for single houses, is a good choice for large scale introduction. Studies within the solar electricity programme SOLEL in Sweden has shown that the energy pay-back period for stand alone systems can be as long as 15-20 years, mainly because the batteries in the system [5]. A more possible solution in the energy changeover that will be necessary for facing out fossil fuel in the future, it is better with large pump hydro power plants, common for several countries. To be able to use large scale solar electricity in Sweden, with the very uneven access of solar radiation due to the high latitudes, cooperation with other countries, both concerning energy production and energy storage, is necessary.

• The electricity usage pattern may change in the future to get a profile that better matches available renewable energy sources. Ten-fifteen years ago, there was a potential lack of electricity during winter daytime in Sweden, which cause a tax system with higher electricity price during these periods. This had the consequence that families, and also industries, tried to situate electricity consuming activities like washing, drying and hot water preparation to evenings and nights as far as possible. Similar tax systems may be necessary in the future to enable larger share of non adjustable renewable electricity production.

Finally, the calculation of A0 that is done in the paper should not be seen as a fixed number, but more an indication of the magnitude of possible PV area that can be installed in Sweden. In the paper both PV technology and electricity consumption are assumed fixed, but this will change in the future. Higher PV performance would reduce A0, but as the share of electricity in the energy mix is growing, even if the energy demand is fixed or slightly decreasing, this would result in larger A0. Further studies, like how PV production match wind energy production, is also planned.

Acknowledgements

We want to thank Kent Boijesson at SERC, Hogskolan Dalarna for helping to organise older weather data and NordPool for using their data for Swedish electricity consumption. The study has been performed with financial help from Elforsk programme Solel.

References

[1] www. NordPool. com (July 2008)

[2] Estevez, Nicoals Sebastian, Photovoltaic Power in the Swedish Grid: to deal with Solar Electricity Overproduction in the Future. Master thesis work, Hogskolan Dalarna, Borlange, Sweden (2007).

[3] Olsson, Catrine och Edin, Niklas, Systemanalys av solkraft vid samkorning med det svenska kraftnatet med lagring av solenergi i vattenmagasin. ("System analysis of solar power in the Swedish grid with energy storage is hydropower ponds”). Thesis, Lund Technical University, Institutionen for Varme — och Kraftteknik, Sweden (1995).

[4] www. abb. com/hvdc (July 2008)

[5] Spante, Lennart, et. al.: Solel 97-99; Ett branschgemensamt FoU-program, slutrapport, Report 00:9, Elforsk (Downloadable with english summary from www. elforsk. se) (2000)

The PV architecture is a new concept for Romania. Consequently, the project aims to achieve demonstrative designs of ecological solar buildings containing in their structure photovoltaic elements, passive solar elements, and modern systems for day lighting. These will be available on-line on the web-site of the project and, additionally, will be presented to building contractors and to the public. In this section of the project we have in view the practical construction of three BIPV (building integrated PV) systems to be integrated in the structure of buildings. The three systems will be equipped with monitoring systems and the necessary infrastructure for transmitting the data to the web-site. A computer-based displaying system

placed in public domain will permit real-time visualisation of the parameters of the installation and, additionally, will transmit technical and economical information referring to the solar/photovoltaic architecture to the large public.

A holistic analysis of the building has to be done before to introduce a BIPV system. The main criteria of such analysis would be as follows:

• opportunity of the BIPV utilisation;

• involvements of the built environment (urban, rural, industrial) towards the building;

• involvements of the BIPV placement towards the building itself (these criteria are linked with volumetric analysis, style, general and particular look of the building envelope);

• specific requirements of the building envelope based on the type of selected BIPV;

• optimum action type and place (analysis of the BIPV systems corresponding with the envelope parts where it would be intended to act);

• technical and operational involvements on the envelope components;

• efficiency of the agreed system;

• financial and payback period involvements of the investment;

• type and way of the produced electrical energy management.

The main activities developed by the project partners are as follows:

Project coordinator (IPA SA):

• elaboration of technical solutions for PV systems integrated into facade and roof elements, including sizing and preparation of the technical documentation for the design of the PV systems to be used in the three demo projects;

• elaboration of the technical information and data support for the development of a data acquisition and processing software;

• software development for sizing building-integrated PV systems;

• design of the PV systems for all real and demo applications within the project.

West University of Timisoara (WUT):

• development of a software for solar radiation estimation (based on the models which can be deduced taking into account the new database);

• achievement of a PV system located at the WUT.

• development in Timisoara of the centre for measuring solar radiation on tilted surfaces.

Polytechnic University of Bucharest (PUB):

• development of a BIPV Laboratory at Physics Department (together with IPA);

• elaboration of IT solutions for the development of a specific website for the performance of all project activities (database administration, online courses, partner’s communication, setting up of a solar architecture library, etc.). The website will be structured on two levels: public and private;

• elaboration of market surveys and of a strategy for the implementation of BIPV systems on the Romanian market;

• drawing up of a guide on building-integrated PV systems;

Polytechnic University of Timisoara (PUT):

• research related to the achievement of the measuring and data centralising instrumentation (electronic data acquisition and processing equipment);

• development of a FIELDBUS type measuring network, of programs associated to interfacing and real-time building of a database with online access;

• studies on the optimal use of solar radiation spectrum areas.

4

Partner University of Architecture and Urbanism in Bucharest “Ion Mincu” (UAUIM):

• analysis of types of civil buildings in the existing stock and evaluation of possibilities of intervention upon these ones by introducing PV panels;

• proposals of interventions in existing civil buildings by integrating the panels within the building envelope;

• experiments related to possibilities of intervention on the covering — terrace of a building of the "Ion Mincu" University and on the framework of the same building (the old building of the School of Architecture), and monitoring of subsequent behaviour;

• participation at the elaboration of market surveys and of a strategy for the implementation of building — integrated PV systems on the Romanian market.

Christian Budig1*, Janybek Orozaliev1, Claudia Rose1, Klaus Vajen1, Elimar Frank1#,

Ruslan Botpaev2, Alaibek Obozov2

1 Kassel University, Institute of Thermal Energy Engineering, Kassel (Germany)

2 Kyrgyz State Technical University, Department for Renewable Energies, Bishkek (Kyrgyzstan)

* Corresponding Author, solar@uni-kassel. de

Abstract

In heat and power plants with so-called open district heating nets, large quantities of cold water (e. g. 12°C) are heated up to supply temperatures (e. g. 60°C) using fossil fuels. This water, however, can be effectively preheated by uncovered collectors before heating up conventionally to the supply temperature. Due to high basic load, low inlet temperature and good climatic conditions in most parts of the Commonwealth of Independent States (CIS), extraordinary solar gains and very low solar heat costs can be achieved during the frost-free season. The objective of this investigation is to identify heat and power plants in the CIS which are appropriate for solar water preheating. For this purpose, large (or central as it is called in the CIS) operated heat and power plants were identified and evaluated. It was found that 38 out of 197 heat and power plants are in principle appropriate for this kind of solar thermal technology. In addition, this study includes an economic analysis of the technology based on previous experimental and theoretical results. Solar heat costs of less than 0.01 €/kWhth and a payback time of about 9 years are expected.

Keywords: uncovered collector, heat and power plants, district heating, CIS

1. Introduction

District heating nets for heat supply are very common in cities of the Commonwealth of Independent States (CIS) and are often combined with large heat and power plants. A representative situation can be found in Bishkek, the capital of Kyrgyzstan with similar latitude as Rome. Officially, about 350 thousands inhabitants in the center of Bishkek receive domestic hot water and energy for space heating from the central Heat and Power Plant (TEZ) of Bishkek City. The real number of consumers is estimated by the local authorities to be twice as much. The district heating net, however, shows some differences to common Central European technologies. It is constructed as an open-circuit system, where domestic hot water is taken by the consumers directly out of the net without any heat exchanger coupling (see Figure 1). Thus, the district heating net in Bishkek has to be refilled with about 3000 m3 per hour of 12°C cold water. This is carried out at the central Heat and Power Plant. Cold water is heated up to 60°C, the temperature level required during summer when no space heating is needed and ambient air temperature is usually higher that 20°C even at night.

This water can, however, be preheated using solar energy before heating up conventionally to the supply temperature. For this purpose uncovered plastic solar collectors (cf. [1]) or multicomponent # Current address: Institut fur Solartechnik SPF, Rapperswil (Switzerland)

solar thermal systems (cf. [2]) can be effectively used due to the low water inlet temperatures and high ambient temperatures.

For this application no solar heat storage is necessary because of the high basic load. Due to the low inlet temperature and excellent climatic conditions (high irradiation, high ambient temperature) very high solar gains can be achieved. For Bishkek specific solar gains are estimated to be around 1000 kWh/m2coll during the frost-free season Mai — September, which is about four times higher than the solar gains typically achieved in swimming pool heating in Central Europe.

But not all district heating nets in the CIS have similar boundary conditions so that not everywhere water preheating with uncovered collectors makes sense. Some district heating nets are not in operation in summer, but only during winter or space heating period. A number of district heating nets are constructed as a closed-circuit system with almost no need for water refilling and relatively high water return temperatures. For closed-circuit systems, other solar thermal technologies, e. g. flat plate collectors, can be used. These, however, are not yet economically competitive with still low, but rapidly increasing energy prices in the CIS and are therefore not considered in this study. Furthermore, some heat and power plants are operated in summer to produce as much electricity as possible use even cooling towers during summer. In this case, no uncovered collectors can be applied since there is no demand for low temperature heat.

The following technical characteristics of the heat and power plant are necessary in order to effectively apply the uncovered collectors or multicomponent solar thermal systems for water preheating

• high basic load (^ no storage is needed + large solar heating system)

• open-circuit or mix-circuit systems (^ low water inlet temperature)

• in operation in the frost-free period

• CHP-operation mode based on the heat load

• available area for uncovered collectors

The objective of this investigation is to estimate the potential of solar water preheating in the CIS by identifying heat and power plants where this technology can be effectively implemented. For

this purpose, an attempt was made to identify and evaluate all large heat and power plants operating in the region.