Performanta energetica a cladirilor

D. Constantinescu, H. Petran, C. Petcu
PERFORMANTA ENERGETICA A CLADIRILOR NOI SI EXISTENTE.
Fundamentare teoretica si aplicatii

Scopul lucrarii Performanta Energetica a Cladirilor Noi si Existente este de a prezenta bazele teoretice ale activitatii de audit energetic in cladiri, cu referire la procesele termice, precum si aplicatiile cele mai sugestive, complementare fundamentarii teoretice. Lucrarea de fata prezinta suportul fizic si matematic al activitatilor de expertiza, diagnoza, certificare si audit energetic proprii cladirilor noi si existente si se adreseaza specialistilor care isi desfasoara activitatea in domeniul cercetarii, proiectarii si invatamantului superior din constructii, instalatii si arhitectura. Sub forma de prezentare si prin continut lucrarea este utila si studentilor care frecventeaza cursurile universitare si postuniversitare si care isi propun sa devina auditori energetici pentru cladiri. Cu toate ca lucrarea nu reprezinta un ghid de calcul a PEC, s-a elaborat un capitol (VIII) sub forma de breviar de calcul cu scopul de a facilita activitatea de transpunere in program de calcul a relatiilor de calcul prezentate atat in reglementarile tehnice autohtone (la elaborarea carora autorii au participat si ale celor care si-au dovedit si isi dovedesc utilitatea, prezentate in cap. VIII al lucrarii), cat si in lucrarea de fata. Bazele lucrarii de fata au fost puse prin cercetarile desfasurate in INCERC Bucuresti de autori in diferite etape, incepand cu anul 1969. In anul 2000 au fost elaborate de autorii lucrarii de fata primele reglementari tehnice in domeniul certificarii si auditului energetic al cladirilor din Romania, cunoscute sub numele codificate NP 048-2000, NP 047-2000 si
NP 049-2000. Meritul reglementarilor romanesti este, in primul rand, acela de fi prefatat directiva europeana 91 / 2002 / CE si apoi de a se fi orientat catre o abordare fenomenologica care nu de putine ori lipseste metodelor recomandate de unele standarde europene. Abordarea "europeana" este una energetica care se refera la intervale de timp predefinite prin chiar rezultatul operatiunii de integrare a fluxurilor termice sub forma cantitatii de caldura. Sezonul cald caracterizat de oscilatii diurne semnificative ale parametrilor climatici este abordat prin utilizarea unor metode simplificate de calcul in care notiunea de grade-zile nu-si gaseste nici o justificare fenomenologica. Metodele de calcul analogic cu referire la suportul retelei electrice analoaga structurilor de inchidere a spatiilor ocupate reprezinta o simplificare inacceptabila care deformeaza atat campul de temperaturi, cat si profilul temperaturilor interioare din spatiile ocupate.
Performanta Energetica a Cladirilor reprezinta una din preocuparile majore ale autorilor in cadrul Laboratorului de Instalatii si Eficienta Energetica a Cladirilor din cadrul INCERC – Bucuresti. Practic, lucrarea de fata pleaca de la bun inceput de la ideea ca a elabora un certificat de performanta energetica sau a analiza pachete de solutii tehnice de modernizare energetica in cazul cladirilor existente, alaturi de a concepe o cladire noua performanta din punct de vedere energetic, reprezinta modele de gandire avand ca numitor comun simularea cantitativa a proceselor de transfer de caldura si masa, pe baza unor modele validate experimental in detaliu la nivel de proces si in ansamblu la nivel de cladire. Suportul validarilor prezentate in lucrare il reprezinta cladiri de tip colectiv din Bucuresti si Cladirea Experimentala cu climat controlat din incinta INCERC – Bucuresti. Prin continut si prin abordare lucrarea reprezinta o noutate in cadrul literaturii de specialitate din Romania.

D. Constantinescu, H. Petran, C. Petcu
ENERGY PERFORMANCE OF NEW AND EXISTING BUILDINGS.
Theoretical fundaments and applications

The aim of the book Energy Performance of New and Existing Buildings is to present the theoretical bases of the energy audit of buildings, with reference to thermal processes, as well as the most suggestive applications, complementary to the theoretical substantiation. The book presents the mathematical and physical support of the energy assessment, diagnosis, certification and auditing activities, specific to new and existing buildings, and is addressed to the research, design and higher education professionals in civil engineering, building equipment and architecture. As form of presentation and contents, the book is useful also to students and postgraduate students which intend to become energy auditors for buildings. Even if the book does not represent a guideline for the calculation of Building Energy Performance, Chapter VIII was conceived as a calculation sheet, in order to facilitate the software implementation of the analytical expressions given both by the Romanian technical regulations (those in the developing of which the authors have participated and those which have shown and show their utility, presented in Chapter VIII of the book), as well as in the present work. The bases of the work were established by the research carried out at INCERC Bucharest by the authors during different periods, starting with 1969. In 2000, the authors of the book developed the first Romanian technical regulations concerning energy certification and audit of buildings, known under the codified identifications NP 048-2000, NP 047-2000 and NP 049-2000. The merit of the Romanian regulations is, in the first place, that of being prefaced the European Directive 91 / 2002 / CE and also that of orienting towards a phenomenological approach which frequently lacks to the methods recommended by certain European standards. The "European" approach is energy-oriented and refers to time periods pre-defined directly through the result of the integration of thermal flows in the form of the quantity of heat. The hot season, characterized by significant daily oscillations of the climate parameters is considered by the use of simplified calculation methods, in which the notion of degrees-days does not find any phenomenological justification. The calculation methods that use the analogy between the electrical network and the building envelope of living spaces represent an unacceptable simplification, which deforms both the field of temperatures and the profile of interior temperatures in those spaces.
The Energy Performance of Buildings represents one of the major subjects of concern in the activity of the authors, at the laboratory of Building Equipment and Energy Efficiency in Buildings at INCERC Bucharest. Practically, the book is written starting from the idea that the issuing of an energy performance certificate or that of analyzing packages of technical solutions for the energy upgrading of existing buildings, together with conceiving a new state-of-the-art building from the energy point of view, represent thinking models having in common the quantitative simulation of the heat and mass transfer processes, based on experimentally validated models, either into detail, at process level, or globally, at building level. The support of the validations presented in the paper is represented by the collective residential buildings in Bucharest and by the Experimental Building with controlled climate at INCERC Bucharest. By contents and approach, the book represents a novelty in the technical literature in Romania.