ROOFS WITH PHOTOVOLTAIC SYSTEMS - Index S.p.A.

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The above output comparison relates to a5-month period (May to September) in 2009(untreated roof with a visible black bituminouscovering) and in 2010 (after treatment).To obtain a rough - but nonetheless indicative- evaluation, the data was comparedwhile taking account of sunshine hours byconsulting meteorological tables for themunicipality of San Giovanni in Marignano(RN).From the calculations performed, discountingthe days affected by persistent rain andassuming production was halved on dayswhen the weather was stormy, it was immediatelyevident that despite a markedincrease in rainfall (mostly occurring in May2010), the system maintained a constantenergy production level over the 5-monthperiod. The final column, listing the datamost relevant to the original purpose of thetest, energy production (in the form of suggestedenergy per sunny day), contains significantlyincreased values and correspondsto a figure of around 8%.In conclusion, a commercial assessmentmay now also be conducted in order toquantify the financial benefit of using extremelyhigh solar reflectance WHITEREFLEX paint.Once the necessary conditions for the approximationof sampling data have beenmet (the periods and sunlight intensity arenot yet firmly established) and the deteriorationand loss of output for the system havebeen calculated (the manufacturers indicatethat any decline in output takes place veryearly on within the operating period), andtaking account of the potentially saleableenergy produced as well as the amountnot required by the mains supply user, thesystem would have yielded an excess ofapproximately 8400 Watts, which is almostenough to cover the cost of purchasingand applying the paint.In short, we could say that the work paysfor itself over the course of a year and creates"wealth" in following years.POWER FIELDIn addition to the systems equipped with crystallinesilicon (used in approximately 85% ofapplications up to this point), other types ofphotovoltaic panels are now becoming morewidespread in Italy.One of the most interesting is an Americanproducedtype, a revolutionary product dueto its easy installation and maintenance procedures,which does not require the use ofmechanical fixing elements or ballasts on theroof. These systems have cylindrical elementsin CIGS (copper, indium, gallium, diselenide),capable of capturing both direct and reflectedsolar radiation from the roof treated with WHITEREFLEX.The increases in energy production should beeven more consistent than the results recordedin the previous test.In the summer of 2009 (application took placeon 29th June) a test was performed which providedsome particularly interesting results.On the date of the first on-site inspection, thecylindrical cell system located on a small roof(approx. 100 m 2 ) with a bituminous surfacecovering self-protected with green slate granuleswas producing energy at a deficit of 36%in comparison with the nominally anticipatedfigure.The system dysfunction was due to the badsolar reflectance values of the roof; the subsequentapplication of WHITE REFLEX paintwould have demonstrated this hypothesis.6 ROOFS WITH PHOTOVOLTAIC SYSTEMS Technical specifications
1 month after application, the energy productiondata was retrieved and, as illustrated by thegraph (see previous page), an increase of 30%was recorded in the current field (and thereforethe power field) produced.The other graph (adjacent to this paragraph)corresponds to the energy produced by thesystem over the course of one sunny day, beforeand after treatment with WHITE REFLEX;it shows a significant improvement, especiallyin the hours in which albedo is at its worst (earlymorning and sunset).DIFFERENCE BETWEEN ANTICIPATED POWER AND ACTUAL POWERTimeBEFOREAfter application the effect of the paint couldbe detected immediately, albeit in a generalisedmanner, by using a solarimeter to measure solarradiation. Solar reflectance increased roughlysevenfold.AFTERIn conclusion, although the experiment is notyet complete, a roof with high solar reflectanceis entirely necessary for cylindrical cellsystems and WHITE REFLEX paint, thanks toits considerable application flexibility (it canbe used on almost all supports), should beMembrane - DifferenceMembrane+Index - Differenceconsidered as one of the most viable solutions.SOME RECOMMENDATIONSextracted from the “L’ENERGIA FOTOVOLTAICA” (PHOTOVOLTAIC ENERGY) publication by ENEACreating a photovoltaic system is not too complicated, but it is a jobwhich should be carried out by specialists. It is nevertheless useful tofamiliarise yourself with a few rules which should be observed in thedesign and application phases.The support structures should be constructed to last at least as longas the system itself, i.e. 25-30 years, and should be installed so as toallow easy access to modules for cleaning and replacement, and toelectric junction boxes for inspection and maintenance. They must alsobe entirely resistant to corrosion and wind.Photovoltaic generators installed on roofs must not interfere with thewaterproofing and insulation of the surfaces; in some cases it may benecessary to create fixed or mobile walkways.A gap must be left between modules, from a minimum of 5 mm for generatorsinstalled in parallel and near other fixed surfaces, up to 5 cm forgenerators which may be subjected to high wind pressures.In the case of roof- or wall-mounted modules, it is essential that a gapof 4-6 cm is left between them so as to guarantee sufficient air circulationand therefore effective cooling of the surface on which the moduleis installed.The interconnecting electricity cables and junction boxes must besuitably sized, conform to electrical regulations and guarantee thespecified insulation, protection and waterproofing classes as required.EDITO DA: ENEA - LUNGOTEVERE THAON DI REVEL, 76 - 00196 ROMA - LUGLIO 2006 - DESIGN: EDIZIONI ALTEA S.R.L. - STAMPA: PRIMAPRINT (VITERBO)S V I L U P P OS O S T E N I B I L EG22-065-022SVILUPPO S OSTENIBILEL’ENERGIA FOTOVOLTAICATechnical specificationsROOFS WITH PHOTOVOLTAIC SYSTEMS7
Page 1 and 2: Technical specification14ROOFS WITH
Page 3 and 4: Supported tubularsystemThe wind and
Page 5: REFLECTANCEBlack bituminous membran
Page 9 and 10: THERMAL INSULATIONThis is required
Page 11 and 12: DOUBLE-LAYER WATERPROOF COVERINGDou
Page 13 and 14: WATERPROOFING AND THERMAL INSULATIO
Page 15 and 16: THERMAL INSULATIONINSULATORS PRE-CO

ROOFS WITH PHOTOVOLTAIC SYSTEMS - Index S.p.A.

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