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  Numarul 2/2012

Volumul 3 (2012), Nr. 2

Aspecte constructive, functionale si energetice generate de schimbarea lui R22 din sistemele frigorifice
Constructive, functional and energy-related aspects generated by the change of R22 in refrigeration systems
L.G. Drughean, A. Ilie, A. Dobrovicescu

Autorii analizeaza comparativ, din punct de vedere teoretic, performantele tehnice ale unui sistem frigorific cu comprimare mecanica, ce poate functiona in domeniul frigului industrial, in domeniul frigului de climatizare si in domeniul pompelor de caldura. Agentii frigorifici considerati in acest studiu si mentionati de literatura de specialitate, ca fiind potentiali inlocuitori ai freonului R22 sunt: R404A; R407C; R410A; R417; R422 A; R424 A; R428; R507. Pentru analiza comparativa s-a trasat ciclul termodinamic, aferent fiecarui agent frigorific utilizat in instalatie, pentru aceeasi temeratura de vaporizare si diferite temperaturi de condensare, respectiv 30 °C, 40°C, 50°C si 55°C. Performantele tehnice ale instalatiei frigorifice au fost exprimate prin urmatorii indicatori: capacitate frigorifica specifica, q0v, [kJ/m3], lucru mecanic specific volumic, lv, [kJ/m3], coeficient de performanta, EER / COP, [-]. In acelasi timp autorii prezinta comparativ caracteristicile fiecarui agent frigorific mentionat anterior referitoare la: - impactul asupra mediului prin GWP (Global Warming Potential) si TEWI (Total Equivalent Warming Impact); - proprietatile termodinamice, corelatia presiune - temperatura, temperatura - volum specific, raport de comprimare; - compatibilitate cu substantele de lubrifiere (ulei); - inflamabilitate si toxicitate.

The authors analyze comparatively the theoretical, technical performance of a mechanical compression refrigeration system that can work in the field of refrigeration, industrial refrigeration air conditioning and heat pump field. Refrigerants considered in this study and the literature mentioned as being potential substitutes for Freon R22 are: R404A, R407C, R410A, R417, R422 A, R424 A, R428, R507. For comparative analysis was drawn thermodynamic cycle, for each refrigerant used in the system for the same setpoints different vaporization and condensation temperature and 30 ° C, 40 ° C, 50 ° C and 55 ° C. Technical performance of the refrigeration system were expressed by the following indicators: specific refrigeration capacity, q0v, [kJ/m3], work specific volume, lv, [kJ/m3], coefficient of performance, EER / COP [-]. At the same time the authors present comparative characteristics of each aforementioned refrigerant on: - Environmental impact by GWP (Global Warming Potential) and TEWI (Total Equivalent Warming Impact); - Thermodynamic properties, correlation pressure - temperature, temperature - specific volume, compression ratio; - Compatibility with substance lubrication (oil); - Flammability and toxicity.

Securitatea si estetica mediului luminos urban din Bucuresti - o necesitate actuala
Safety and environmental aesthetics urban light in Bucharest - a present must
Cornel Bianchi, Ana-Maria Bianchi, Mihai Husch, Camelia Burlacu

Mediul luminos urban din Romania a facut progrese deosebite dupa 1990, atat din punct de vedere cantitativ cat si calitativ, datorita eforturilor depuse de CNRI-CIE prin cursurile de perfectionare profesionala in special si de receptarea acestora, care a condus la ridicarea nivelului profesional al firmelor de varf.

Bright Urban Environment in Romania after 1990 made substantial progress both in terms of quantity and quality, thanks to the efforts of CNRI-CIE through professional training courses in particular and their reception that led to raising the professional level of firms peak.

Optimizarea procesului de indepartare a fosforului prin aditie chimica. Studiu de caz: Statia de epurare a apelor uzate Oradea
Optimizing phosphorus removal by chemical addition. Case Study: Wastewater treatment plant Oradea
Gheorghe-Constantin Ionescu, Emil Gligor, George-Lucian Ionescu

Apa uzata contine o serie de poluanti, dintre care unii sunt indepartati mai mult sau mai putin in treptele de epurare conventionala, iar altii sunt retinuti extrem de putin sau deloc, in statiile de epurare clasice. Problemele acute legate de protectia apelor au condus la impunerea unor conditii severe legate de concentratiile limita admise in efluentul epurat deversat in emisarii naturali.

Wastewater contains a number of pollutants, some of which are removed more or less conventional purification steps, while others are retained very little or no conventional treatment plants. Acute problems of water protection led to the imposition of severe conditions related to the permitted limit concentrations in treated effluent discharged to natural emissaries.

Analiza exergo-energetica a diferitelor tipuri de instalatii frigorifice în solutie LiBr-Apa
Energy-exergo analysis of different types of refrigeration in LiBr-Water solution
Alina Girip, Dragos Hera

In aceasta lucrare se realizeaza o analiza a performantelor termoenergetice pentru diferite tipuri de instalatii cu absorbtie in solutie BrLi-H2O intr-o treapta si 2 trepte, utilizand principiul al II-lea al termodinamiicii. Pierderile exergetice datorate ireversibilitatilor interne si externe in timpul parcugerii ciclului termodinamic sunt calculate cu ajutorul metodei exergetice.

This paper provides a performance analysis for different thermal power plants BrLi-H2O absorption solution-stage and 2-stage, using the second principle of termodynamics. Exergy losses due to irreversibility during internal way and external thermodynamic cycle are calculated using exergy method.

Raspunsul cladirilor cu fatadele duble vitrate integrate la exigentele DE 2010/31/UE
The response of buildings with double glazed facades integrated to the 2010/31/EU exigencies
Victoria Cotorobai, Theodor Mateescu, Catalin Grigoras

Fatadele duble vitrate au cunoscut si cunosc o imbunatatire continua dar utilizarea acestora a capatat vizibilitate abia dupa anii 2000. Fatadele duble vitrate au in prezent performante ridicate, capata atribute noi, devin termo-active si chiar inteligente si sunt integrate in cladiri cu diferite functiuni, in zone geografice diferite, .... Insa, in actualul context, energetic si tehnologic, ele trebuie sa raspunda adecvat si exigentelor impuse cladirilor prin DE 31/2010/UE. In lucrare se prezinta rezultatele unor experimente numerice realizate in vederea identificarii celor mai bune modalitati de structurare a fatadelor duble vitrate in scopul realizarii de cladiri performante energetic.

Double glazed facades have known and are known continual improvement but their use has become visibility only after 2000. They have now high performance, gains new attributes become even smart thermo-active and integrated in buildings with different functions in different geographical areas, .... However, in the current context, energy and technology, they must respond appropriately and requirements imposed by DE 31/2010/UE buildings. This paper presents the results of numerical experiments performed to identify the best ways of structuring double glazed facade in order to achieve energy efficient buildings.

Consideratii despre softuri folosite in modelarea si/sau simularea centralelor de cogenerare
Considerations about the software used in modeling and/or simulation of cogeneration plants
Radu-Alexandru Baciu, Frunzulica R., Tarlea G.M.

Aceasta lucrare prezinta o scurta descriere a softurilor folosite la nivel international pentru simularea si/sau modelarea centralelor de cogenerare in ansamblul lor sau al unor procese ori tehnologii folosite in tehnica cogenerarii. Simularile se pot face in majoritatea cazurilor atat din punct de vedere tehnic cat si economic.

This paper presents a brief description of the software used internationally for simulation and/or modeling of cogeneration plants in whole or processes or technologies used in cogeneration technology. Simulations can be done in most cases from both technically and economically way.

Achizitiile publice- cinci probleme majore in atragerea fondurilor U.E.
Procurement - five major problems in attracting EU funds
Nicolae Postavaru

Achizitiile publice sunt mijlocul prin care banii publici, adica circa 80 % din fondurile ce se vehiculeaza pe piata, ajung la contractori, subcontractori, furnizori, consultanti si ajung inapoi la stat . Gradul de eficienta a utilizarii acestor fonduri trebuie sa ne intereseze pe toti, deoarece sunt banii proveniti de la noi toti .Mai mult, Comunitatea Europeana ne ajuta din fondurile ei publice sa ne realizam unele proiecte absolut necesare dezvoltarii sociale si economice, pentru a putea deveni un stat membru dezvoltat la un nivel cat mai aproape de cel mediu din Comunitate . Insa noi avem mari problem de sistem, ca sa consumam aceste fonduri, iar un loc central in acest sistem imperfect il au achizitiile publice, incriminate de multi dintre oficialii europeni. In lucrarea de fata prezint problemele majore ale sistemului de achizitii publice, care nu functioneaza, desi "avem legi la nivel european". Concluzia este ca trebuie regandit tot sistemul de derulare al investitiilor publice si totul cat mai repede si profesionist cu accent pe problemele mentionate pentru sistemul de achizitii. Altfel spus, am pus piese bune de la diferite marci intr-o masina, si acum ne miram ca nu merge.

Procurement means by which public money, about 80% of the funds that are circulating in the market, reaching contractors, subcontractors, suppliers, consultants and get back to state. The effectiveness of using these funds should concern us all, because the money is coming from us all. Moreover, the European Community helps them public funds to realize some projects indispensable social and economic development, in order to become Member State developed to a level closer to the average dinComunitate. But we have big problem of system, to consume these funds, and central to this system we have imperfect procurement, it is incriminate by many European officials. The paper presents the challenges of the public procurement system that does not work, though, we have laws in Europe ". The conclusion is that we must rethink the whole system of running the public investments and everything as quickly and professionally with emphasis on those issues for procurement system. In other words, we have good songs from different brands in a car, and now we wonder why it does not work.

 
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