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  Numarul 1/2011

Volumul 2 (2011), Nr. 1

Conceptia corecta si moderna a sistemelor de iluminat interior - O necesitate actuala
Concept of modern sound and lighting systems inside - an actual necessity
Cornel BIANCHI, Dan MOROLDO

Articolul prezinta o abordare originala in ceea ce priveste folosirea luminii naturale in interiorul cladirilor, obtinindu-se astfel o mai buna eficientizare a consumului de energie prin folosirea unor mijloace moderne de iluminat a diverselor spatii.

The article presents an original approach regarding the use of natural light inside buildings, thereby achieving better energy efficiency by using modern means of lighting the various areas.

Sisteme rezidentiale de pompe termice. Eficienta, pret si confort
Residential Heat Pump Systems. Efficiency, Price and Comfort
Ioan Boian, Alexandru Serban, Florin Chiriac

Lucrarea prezinta instalatia de incalzire realizata la Catedra de Instalatii a Universitatii din Brasov bazata pe pompa termica impreuna cu evaluari energetice si de eficienta estimate in faza de conceptie in vederea asigurarii confortului termic din laborator precum si unele rezultate experimentale obtinute in perioada de testare. Pompa termica cu comprimare mecanica asigura temperatura necesara din laboratorul de la subsolul cladirii, care nu beneficiaza de aport solar fiind astfel "izolata" de influentele atmosferei si de cele solare. Din aceasta cauza furnizarea de caldura in laborator este necesara si in sezonul cald, insa cu o pondere mai redusa. Pompa termica este asistata si de un panou solar-termic cu tuburi vidate.

A heat pump sytem designed and realized in the the Building Facilities Department at Transylvania University of Brasov is presented together with some evaluations concerning the energy efficiency and comfort speciffic for the design phase. Results from testing carried out in a below the grade laboratory, having low solar gain, with hydronic heating system show the cycling operationof the heat pump. The heat pump operating all around the year is solar assisted by an evecuated solar collector.

Aspecte privind senzorii satelitari optici folositi in silvicultura si studiul padurii
Aspects of optical sensors satellitare used in forestry and forest research
Iosif Vorovencii

Teledetectia satelitara este o tehnica relativ noua ce permite, prin mijloacele sale, achizitionarea de imagini satelitare pe suprafete mari de teren. Realizarile acesteia sunt evidente atat in planul senzorilor amplasati pe platformele satelitare cat si in ceea ce priveste metodele folosite la prelucrarea inregistrarilor in vederea obtinerii produselor finale. Printre sectoarele in care datele de teledetectie au aplicabilitate imediata se numara si cel forestier. Faptul ca imaginile satelitare preluate au diferite caracteristici tehnice, printre care cea mai importanta fiind rezolutia spatiala, determina ca realizarile teledetectiei satelitare in acest sector sa fie diferentiate la nivel de studiu si analiza generala a padurii, dar si la nivel de arboret. In acest articol sunt prezentate aspecte privind principalii senzori satelitari curenti aflati pe orbite care achizitioneaza imagini satelitare ce pot fi utilizate si in sectorul forestier.

Satellite remote sensing is a relatively new technique that allows, by own means, the acquisition of satellite images on large areas. Accomplishments are evident both in terms of sensors placed on satellite platforms and the processing methods used to obtain the final products. Among the sectors which have immediate application of remote sensing data is included and the forestry. The fact that satellite images aquired with different technical characteristics, among which the most important being the spatial resolution, satellite remote sensing makes the achievements in this sector to be differentiated from the general study and analysis of the forest to the stand level. This article presents the main aspects of current satellite sensors which acquire satellite images that can be used in forestry.

Schimbatoare de caldura compacte utilizate ca vaporizatoare in instalatiile frigorifice
Plate heat exchangers used as evaporators in refrigeration plants
Anica Ilie, Liviu Geo Drughean, Dragos Hera

Lucrarea prezinta rezultatele experimentale privind performantele termice ale unui vaporizator cu placi dintr-o instalatie frigorifica cu amoniac. Instalatia experimentala functioneaza in toate variantele de alimentare a vaporizatorului: functionare uscata (alimentare prin ventil de reglaj termostatic), functionare inecata (cu alimentare gravimetrica din separatorul de lichid), functionare cu circulatie fortata (alimentare cu pompa). Cercetarile experimentale au urmarit determinarea : puterii termice pe partea amoniacului, puterii termice pe partea solutiei glicolate, puterii electrice consumate de compresor si a coeficientului global de transfer de caldura. Cercetarile au avut drept scop o analiza comparativa a performantelor termice ale instalatiei experimentale, in functie de sistemul de alimentare cu agent lichid a vaporizatorului: cu pompa de circulatie, gravimetric si cu ventil termostatic.

This paper reports experimental results on a plate heat exchanger used as evaporator in a single stage compression system working with ammonia. The experiments have been carried out in the Laboratory for Thermodynamics of the Technical University for Civil Engineering in Bucharest. The experimental research was meant to determine: the heat flow rate on the ammonia side, the heat flow rate on the glycol solution side, the electrical power input for screw compressor, the overall heat transfer coefficient, for different operating conditions and for a given geometric configuration. This paper reports comparative experimental results on the thermal performances of the same evaporator feed in different mode with liquid agent: forced circulation, thermosiphon and thermostatic valve. The present interest of this paper comes also from its focus on ammonia – a natural and ecological refrigerant having no ozone depleting potential and low global warming effect.

Optimizarea procesului si rentabilizarea instalatiilor de obtinere a gazului de fermentatie in statiile de epurare ale apelor uzate prin folosirea surselor neconventionale
Optimization and profitability of fermentation gas production facilities in wastewater treatment plants, using unconventional sources
Gheorghe-Constantin Ionescu, George-Lucian Ionescu, Emil Gligor

Aceasta lucrare trateaza posibilitatea de a utiliza si valorifica energia solara si energia geotermala, privite ca resurse energetice alternative la energia electrica pentru optimizarea procesului si rentabilizarea instalatiilor de obtinere a gazului de fermentatie, in statiile de epurare a apelor uzate. Aceste instalatii furnizeaza gaz combustibil, dar sunt mari consumatoare de energie. Prin folosirea surselor neconventionale este posibila rentabilizarea lor.

This paper deals with the possibility of using and exploiting solar and geothermal energy resources, considered as an alternatives to electricity for process optimization and profitability of gas production facilities in fermentation wastewater treatment plants. These facilities provide fuel gas, but they are large energy consumers. By using non-conventional energy sources we can increase their profitability.

Modelare fizico-matematica a incercarii la foc a elementelor de constructie
Physical and mathematical modeling for the fire testing of construction elements
Nicolae Antonescu, Niculae Antonescu, Dan-Paul Stănescu

Testele de rezistenta la foc ale elementelor de constructie sunt prin natura lor distructive si deci nerepetabile. Este util ca in anumite cazuri sa se realizeze o modelare prealabila predictiva cu scopul de a oferi o imagine asupra probabilitatii de reusita a testului si eventual pentru a preciza momentele cheie, fie pentru concentrarea observatiilor, fie pentru luarea unor masuri de siguranta. Modelul prezentat reprezinta imbinarea dintre experienta de modelare fizica si matematica a autorilor si experienta practica de testare la foc si proiectare de standuri de incercare a acestora. Este prezentat un instrument de modelare care sta la baza unui program de calcul specializat si conditiile de rulare ale acestuia.

Tests of fire resistance for the construction elements are destructive by nature and therefore not repeatable. It is useful in certain cases to achieve a predictive modeling in order to offer an image of the chances of success for the test and possibly to clarify key moments, either for concentrating observations or for taking some special safety measures. The model represents the sum between author's physical and mathematical modeling experience in the field of heat and mass transfer and their practical experience in the field of fire testing installations design and operation. The paper presents a modeling instrument which generated a specialized computer programme and describes its running conditions.

Proiectarea acustica a salii multifunctionale din Calarasi
Multipurpose room acoustic design from Calarasi
Mariana Cristina STAN, Cristian NICOLAE

Proiectarea acustica a salii multifunctionale din Calarasi a fost facuta odata cu proiectarea arhitecturala, urmarindu-se o distributie cat mai uniforma a sunetului pe toata suprafata ocupata de auditori si un nivel cat mai redus al zgomotului perturbator, provenit atat din exteriorul salii cat si din instalatia de climatizare a acesteia. Pentru tratamentele acustice au fost propuse atat materiale care au aspectul lemnului (TOPAKUSTIK, placi MDF furniruit ) cat si placi gips-carton cu grosime de 12,5 mm, avand la intrados placi din vata minerala. Valorile calculate pentru duratele de reverberatie se incadreaza in limitele admisibile precizate in legislatia tehnica in vigoare.

Multipurpose room acoustic design in Calarasi was made with the architectural design, as aiming at a more uniform sound distribution throughout the area occupied by the auditors and as low a level of disturbing noise, both from outside the room and its air conditioning plant. For acoustic treatments have been proposed wood materials (TOPAKUSTIK, MDF veneered boards) and gypsum 12.5 mm thick boards; having the soffit panels with mineral wool. The calculated values for reverberation times is within the allowable limits specified in the present technique legislation.

 
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