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BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI<br />
BULLETIN OF THE POLYTECHNIC INSTITUTE OF IAŞI<br />
Published by the<br />
„GHEORGHE ASACHI” TECHNICAL UNIVERSITY OF IAŞI<br />
Tome LVI(LX), Fasc. 3 2010<br />
C O N T E N T S<br />
Pag.<br />
NANA YAW AMPONSAH (France), OLIVIER LE CORRE (France) and<br />
IBRAHIM DINCER (Canada), eMergy: Back to Fundamentals<br />
(English, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1<br />
CLAUDIA IONIŢĂ, MIRCEA MARINESCU, ALEXANDRU DOBROVI-<br />
CESCU and EUGENIA-ELENA VASILESCU, Thermoeconomic<br />
Analysis of a Combined Heat and Power System (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11<br />
FEDOR GROSU (Moldova), MIRCEA BOLOGA (Moldova) and OLEG<br />
MOTORIN (Molova), On Simulation of Wet Air Convection in the<br />
Inclined Capacitor (English, Romanian summary) . . . . . . . . . . . . . . . . . . 21<br />
DAN CONSTANTIN OSPIR (France), STEPHANE FOHANNO (France),<br />
CĂTĂLIN POPA (France), NELU-CRISTIAN CHERECHEŞ et<br />
CĂTĂLIN POPOVICI, Étude d’un écoulement de convection naturelle<br />
dans un canal vertical chauffé asymétriquement (French, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29<br />
CORNELIU MOROIANU, Mathematical Model for Burning the Liquid Fuel<br />
Droplet in a Hot Oxidizing Environment (English, Romanian summary) . 39<br />
DANIELA POPESCU, SVEN BIENERT (Austria) and CHRISTIAN<br />
SCHÜTZENHOFER (Austria), Methodology for Calculation of Added<br />
Value Generated by Energy Efficiency (English, Romanian summary). . .<br />
ALEXANDRU CHISACOF, DRAGOŞ PAVEL and VALERIU PANAI-<br />
TESCU, Jet of Mist Warm Water Behavior in Interaction with<br />
Hydrocarbon Flame (English, Romanian summary) . . . . . . . . . . . . . . . . .<br />
NICOLAE BĂRAN, GHEORGHE BĂRAN, GABRIELA MATEESCU<br />
and ALEXANDRU SORIN PĂTULEA, Water Oxygenation (English,<br />
Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
ELENA EUGENIA VASILESCU, GHEORGHE POPESCU, CLAUDIA IO-<br />
NIŢĂ, VALENTIN APOSTOL and HORAŢIU POP, Comparative<br />
Energy and Exergy Analysis of the Absorption, Resorption and Complex<br />
49<br />
57<br />
69
Absorption-Resorption Systems (English, Romanian summary). . . . . . . . 77<br />
BOGDAN HORBANIUC et GHEORGHE DUMITRAŞCU, Allocation optimale<br />
des échangeurs de chaleur dans les systèmes bootstrap en boucle<br />
ouverte des aeronefs (French, Romanian summary) . . . . . . . . . . . . . . . . .<br />
DRAGOŞ HERA et CĂTĂLINA VASILESCU, Analyse des performances<br />
d’une pompe à chaleur à absorption (French, Romanian summary) . . . . .<br />
MIHAI NAGI, IOAN-DANIEL CĂRĂBAŞ and PAUL ILIEŞ, Wavy Fins<br />
Pitch Influence on Water-Air Heat Exchanger Performance (English,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
RAHAL BOUSSEHAIN (France), ELENA EUGENIA VASILESCU,<br />
YOUCEF ABDELLOUCHE (France), MICHEL FEIDT (France) et<br />
ALEXANDRU DOBROVICESCU, Exergy Analysis of the Transient<br />
Regimes of Vapor Compression Refrigeration Systems (English,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
NADÈGE CHATAGNON (France), MARC BACHMANN (France), GUIL-<br />
LAUME ANIES (France) and JEAN CASTAING-LASVIGNOTTES<br />
(France), Simulation of a Domestic Absorption Chiller (English,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
R. TOUAIBI (Algeria), M. TAHAR ABBES (Algeria), R. BOUSSEHAIN<br />
(Algeria), M . FEIDT (Algeria), E. VASILESCU, M. COSTEA et B.<br />
KHELIDJ (Algeria), Modélisation d’un système de rafraichissement<br />
solaire par absorption utilisant (H 2 O−libr) (French, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
TEONA LOZONSCHI, On Pressurization of a Compartment Due to Rupture<br />
of Coolant Piping in a Nuclear Power Plant (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
STOIAN PETRESCU, LAVINIA GROSU (France), MONICA COSTEA,<br />
PIERRE ROCHELLE (France), CĂTĂLINA DOBRE et CAMELIA PE-<br />
TRE, Analyse théorique et expérimentale d’une machine à froid de<br />
Stirling (French, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
LATRA BOUMARAF (Algeria), PHILIPPE HABERSCHILL (France) et<br />
AHMED BENSAFI (France), Performances d’une machine frigorifique<br />
munie d’un détendeur à E\ejecteur utilisant les fluides R134a et<br />
HFO1234yf (French, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . .<br />
AHLEM ARFAOUI OMRANI (France), REJEB BEN MAAD (Tunis),<br />
MOURAD REBAY (France), COLETTE PADET (France) et JACQUES<br />
PADET (France), Refroidissement d’un composant électronique par<br />
convection forcée à l’aide de déflecteurs longitudinaux (French,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
VIORICA CEBRUCEAN, IOANA IONEL and DUMITRU CEBRUCEAN,<br />
Post-Combustion CO 2 Capture from Coal-Fired Power Plants (English,<br />
Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
87<br />
97<br />
107<br />
113<br />
123<br />
135<br />
145<br />
155<br />
167<br />
179<br />
191
MIRCEA BOLOGA (Moldova), FEDOR GROSU (Moldova), ALBERT<br />
POLICARPOV (Moldova) and OLEG MOTORIN (Moldova), Heat<br />
Transfer at Condensation of a Gas-Vapor Mixture in an Electric Field<br />
(English, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
A. VAUDREY (France), P. BAUCOUR (France), F. LANZETTA (France) et<br />
R. GLISES (France), Éfficacités et rendements des systèmes piles à<br />
combustible (French, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . .<br />
PASCAL STOUFFS (France), Microgénération: Choix du moteur thermique<br />
(French, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
DANIEL DINESCU (France) and MOHAND TAZEROUT (France), Engine<br />
Air-Charge Regression Model (English, Romanian summary) . . . . . . . . .<br />
DAN PAUL STĂNESCU, NICOLAE N. ANTONESCU et NICULAE AN-<br />
TONESCU, Une modélisation du transfert de chaleur et de masse au<br />
serpentines de tuyaux gaufrés des chaudières à condensation (French,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
DAN ANDREI, Mesures de la pression instantanée dans un compresseur à<br />
piston et comparaison avec des résultats théorique (French, Romanian<br />
summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
ANA-MARIA BIANCHI, SORIN DIMITRIU and FLORIN BĂLTĂREŢU,<br />
Energy Recovery of Combustible Gases from Geothermal Waters by<br />
Cogeneration Units with Internal Combustion Engines (English,<br />
Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
KRISZTINA UZUNEANU and EUGEN GOLGOŢIU, Computational<br />
Modelling of Thermal Stresses in the Combustion Chamber of a Spark<br />
Ignition Engine Fueled with Ethanol-Gasoline Blends (English,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
SALVADORE MUGUREL BURCIU, Computer Simulation of Nonstationary<br />
Flow through the Turbocharger Unit Charge of Supercharged<br />
Diesel Engines (English, Romanian summary). . . . . . . . . . . . . . . . . . . . . .<br />
GHEORGHE MANOLACHE, EDWARD RACOŞI, RADU ROŞCA and<br />
SORINEL TALIF, A New Solution to Improve the Contact Conditions<br />
in the Distribution Systems of the Internal Combustion Engines (English,<br />
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
ADRIAN IRIMESCU, DĂNILĂ IORGA, LIVIU MIHON and IOAN HITI-<br />
CAŞ, Experimental Validation of a Numerical Method for Calculating<br />
Port Injection Air-Fuel Mixture State Parameters (English, Romanian<br />
summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295<br />
STOIAN PETRESCU, NICOLAE BORIARU, CRISTIAN LEONTIEV,<br />
MONICA COSTEA and CAMELIA PETRE, Irreversible Semi-Diesel<br />
Cycle Approach Based on the Direct Method from Finite Speed<br />
201<br />
207<br />
217<br />
229<br />
237<br />
249<br />
257<br />
267<br />
275<br />
285
Thermodynamics (English, Romanian summary) . . . . . . . . . . . . . . . . . . .<br />
301<br />
RAMILA GHEITH (France), FETHI ALOUI (France), MOHAND TAZE-<br />
ROUT (France) et SASSI BEN NASRALLAH (Tunis), Étude thermodynamique<br />
de l’influence de la pression de charge initiale sur<br />
l’amélioration des performances d’un moteur Stirling de type Gamma<br />
(French, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
ILINCA DINU et OANA GHEORGHIŢĂ, Recovery of Organic Waste in<br />
Their Recycling in Agriculture (English, Romanian summary) . . . . . . . .<br />
MANUELA ELENA GEORGESCU, LUCIAN MIHĂESCU, IONEL PÎŞĂ,<br />
TUDOR PRISECARU, ION OPREA and GABRIEL NEGREANU,<br />
Some Experimental Aspects of Biomass Burning (English, Romanian<br />
summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
RAHAL BOUSSEHAIN (France), DIMITER DIMITROV (Bulgaria) et<br />
MICHEL FEIDT (France), Utilisation simultanée de chaleur et de froid<br />
en industrie agro-alimentaire, à l’aide de machines à compression mécanique<br />
de vapeur: quell critère d’efficacité? (French, Romanian summary)<br />
NADIA MRAD (France), FETHI ALOUI (France), MOHAND TAZE-<br />
ROUT (France), SASSI BEN NASRALLAH (Tunis) et HASSEN<br />
ABDALLAH (Tunis), Valorisation des graisses animales comme<br />
biocombustible pour moteurs Diesel (French, Romanian summary) . . . .<br />
CAMELIA CIUBOTĂ-ROŞIE, LAURA BULGARIU, CEZAR CATRI-<br />
NESCU, IRINA VOLF and MATEI MACOVEANU, Study of Biodiesel<br />
Obtained through Valorification of Biomass (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
NATALIA POPOVA (Moldova), ANDREI PAPCHENKO (Moldova) and<br />
MIRCEA BOLOGA (Moldova), Influence of Electroplasmolysis and<br />
Thermal Treatment on Qualitative Properties of Vegetable Raw<br />
Materials (English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
CORINA DANA CERNĂIANU et MARIN BICĂ, Recherches expérimentales<br />
concernant le processus de séchage des céréales à double<br />
sources d’énergie (French, Romanian summary). . . . . . . . . . . . . . . . . . . .<br />
MIRCEA BOLOGA (Moldova), ELVIRA SPRINCEAN (Moldova), ALE-<br />
XANDRU BOLOGA (Moldova), ALBERT POLICARPOV (Moldova)<br />
and TATIANA STEPURINA (Moldova), Electrophysical Methods for<br />
Recycling of the Secondary Milk Products (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
PETRE RĂDUCANU, Aspects Regarding the Design of a Rotary Dryer for<br />
an Equipment which Compresses Sawdust (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
SEVERIN CĂZĂNESCU and RALUCA ALEXANDRA CĂZĂNESCU,<br />
Heating and Cooling Solutions of New Residential and Office Building<br />
Districts in Sustainable Development Context (English, Romanian<br />
313<br />
323<br />
333<br />
339<br />
349<br />
357<br />
365<br />
369<br />
381<br />
391
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
401<br />
DAN-TEODOR BĂLĂNESCU and MARIO-VLAD HOMUTESCU, An<br />
Innovative Solution for Clean Terrestrial Propulsion: Small Scale<br />
Combine Cycle Unit. Performance Evaluation (English, Romanian<br />
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
KRISZTINA UZUNEANU, DAN DRĂGHIA et EUGEN GOLGOŢIU, Estimation<br />
du facteur de détérioration des émissions polluantes pour le parc<br />
d’automobiles, en fonction de l’age et du nombre de kilomètres parcouurs<br />
(kilométrage) (French, Romanian summary). . . . . . . . . . . . . . . . .<br />
MONICA CHERECHEŞ, CĂTĂLIN POPOVICI et NELU-CRISTIAN<br />
CHE-RECHEŞ, Determination de la conductivite thermique dans les<br />
materiaux de construction (French, Romanian summary) . . . . . . . . . . . . .<br />
IOAN CALDARE, Research and Studies on Energy Efficient Solutions for<br />
Environmental Protection in the Heating and Cooling Systems for<br />
Scientific Research Laboratories of the University Campus Braşov<br />
(English, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .<br />
MIRCEA IVĂNOIU, Structures et adaptation pédagogiques dans la<br />
constitution d’une specialisation de génie mécanique: systèmes et<br />
équipements thermiques (SET) (French, Romanian summary) . . . . . . . .<br />
411<br />
421<br />
429<br />
439<br />
451<br />
eMergy: BACK TO FUNDAMENTALS<br />
by<br />
NANA YAW AMPONSAH, OLIVIER LE CORRE<br />
and IBRAHIM DINCER<br />
Abstract. In this paper, it is aimed to study how to compare<br />
renewable energies (wind, solar, etc.) and fossil fuel-based energies<br />
qualitatively by going beyond both the first-and the second-law of<br />
thermodynamics. In this regard, Prof H.T. O d u m, from the University<br />
of Florida, has introduced eMergy, meaning "Embodied Energy" to<br />
include the pathway of a present form of energy. D. S c i e n c e m a n<br />
also used eMergy to refer to the concept of energy memory. Nonrenewable<br />
fossil fuels (such as gasoline, natural gas, etc.) are mainly the<br />
result of thousand-year-old biomass decomposition. Then, in order to<br />
compare renewable and non-renewable energies, one needs utilize the<br />
same scale. Hence, eMergy takes its source. In this paper, the eMergy
concept is first explained through a simple thermodynamic example: a<br />
hot water storage tank. This system is then used to explain the relation<br />
between energy and time. Thus, a contribution is made to dynamic<br />
eMergy calculations through the evaluation of this system, as it differs<br />
from several published static emergy calculations.<br />
Key words: energy, dynamic system.<br />
THERMOECONOMIC ANALYSIS OF A COMBINED HEAT<br />
AND POWER SYSTEM<br />
by<br />
CLAUDIA IONIŢĂ, MIRCEA MARINESCU, ALEXANDRU<br />
DOBROVICESCU and EUGENIA-ELENA VASILESCU<br />
Abstract. This paper presents exergetic and economic analyses as<br />
well as a simulation of a cogeneration system based on gas turbine.<br />
The exergy analysis is based on the first and second laws of<br />
thermodynamics. In these analyses, mass and energy conservation<br />
laws were applied to each component of the system. Quantitative<br />
balances of the exergy and exergetic cost for each component, and for<br />
the whole system was carefully considered. The exergoeconomic<br />
model, which represented the productive structure of the system<br />
considered, was used to visualize the cost formation process and the<br />
productive interaction between components. The results showed good<br />
agreement with the reported data.<br />
Key words: cogeneration, exergetic product, exergetic fuel,<br />
exergetic efficiency, optimization.<br />
ON SIMULATION OF WET AIR CONVECTION IN THE<br />
INCLINED CAPACITOR<br />
by<br />
FEDOR GROSU, MIRCEA BOLOGA and OLEG MOTORIN<br />
Abstract. Possibility of obtaining water and electric power from<br />
atmosphere is shown. Simulation of moisture circle and electric charge<br />
separation in near Earth space is carried out and the density of the<br />
convection electric current produced by the electrohydrodynamic channel
is determined. The obtained results are interested from the point of view<br />
of modelling of processes in the stormy clouds.<br />
Key words: renewable energy, natural convection, charge<br />
separation, electro-hydrodynamics.<br />
ÉTUDE D’UN ÉCOULEMENT DE CONVECTION NATURELLE<br />
DANS UN CANAL VERTICAL CHAUFEÉASYMETRIQUEMENT<br />
par<br />
DAN CONSTANTIN OSPIR, STEPHANE FOHANNO, CĂTĂLIN<br />
POPA, NELU-CRISTIAN CHERECHEŞ and CĂTĂLIN POPOVICI<br />
Abstract. This paper deals with the experimental and numerical<br />
study of flow in a vertical channel heated asymmetrically. The<br />
experiments are performed for a modified Rayleigh number (Ra *)<br />
corresponding to the boundary layer regime. The dynamic structure of<br />
the flow is characterized via visualization techniques by using laser<br />
tomography discrete and continuous tracers across the midline of the<br />
channel. These results are compared with computer simulations using the<br />
laminar model. Experimentally and numerically, an ascending boundary<br />
layer is formed near the heated wall. This upward flow is accompanied in<br />
both cases, by a return flow of variable length, powered by the fluid<br />
entering through the upper channel near the unheated wall.<br />
Key words: vertical channel, natural convection, experimental<br />
study, numerical simulation.<br />
MATHEMATICA MODEL FOR BURNING THE LIQUID FUEL<br />
DROPLET IN A HOT OXIDIZING ENVIRONMENT<br />
by<br />
CORNELIU MOROIANU<br />
Abstract. It was proposed a mathematical model for burning the<br />
liquid fuel drop in a hot oxidizing environment. The model was<br />
numerically solved by the finite element method. The droplet ignition<br />
periods were calculated as a function of ambient temperature, oxygen<br />
concentration, initial droplet diameter and activation energy.<br />
Key words: droplet, burning, mathematical model
METHODOLOGY FOR CALCULATION OF ADDED VALUE<br />
GENERATED BY ENERGY EFFICIENCY<br />
by<br />
DANIELA POPESCU, SVEN BIENERT and CHRISTIAN<br />
SCHÜTZENHOFER<br />
Abstract. The paper presents a method to be used for estimation of<br />
value of buildings, by including energy efficiency aspects. The method is<br />
based on calculation of the added value generated by costs of potential<br />
energy savings. A case study, based on real-estate market data from the<br />
city of Iasi is presented. The results confirm that by taking into<br />
consideration costs of potential energy savings in valuation procedure,<br />
the estimated value of properties is calculated more correctly.<br />
Key words: Energy Performance Certificate, valuation, sales<br />
comparison approach, energy savings.<br />
JET OF MIST WARM WATER BEHAVIOUR IN INTERACTION<br />
WITH HYDROCARBON FLAME<br />
by<br />
ALEXANDRU CHISACOF, DRAGOS PAVEL and VALERIU<br />
PANAITESCU<br />
Abstract. The paper presents the theoretical and experimental<br />
aspects concerning the jet using the mist of warm water for the<br />
hydrocarbon flame extinguish. In the first part of the work are shown the<br />
specific theoretical aspects concerning the liquid phase evaporation in a<br />
surrounding as a function of the humidity and temperature. This fact<br />
generates a change of the atmosphere temperature and composition.<br />
Based on these particularities of the droplet evaporation processes, an<br />
experimental bench was developed. The influence of the liquid<br />
temperature on the fineness spray atomisation in the surrounding was<br />
exposed. The elements resulting from the experimental tests as the jet<br />
development and evaporation were exposed. The experiment suggests<br />
that the liquid phase in contact with the flame evaporates<br />
instantaneously. Consequently, due to the huge volume of vapor, the<br />
oxygen concentration in the mixture might falls under the ignition limit.
Also, the surrounding temperature decreases due to the heat absorption.<br />
The experimental tests show that by the liquid preheating, the<br />
enhancement of the evaporation process occurs. The proposed system is<br />
a clean one, and may be use in the fire extinguish equipment.<br />
Key words: droplet evaporation, mist jet dispersion, fire<br />
extinguish, jet thermal cone.<br />
WATER OXYGENATION<br />
by<br />
NICOLAE BĂRAN, GHEORGHE BĂRAN, GABRIELA<br />
MATEESCU and ALEXANDRU SORIN PĂTULEA<br />
Abstract. In this paper the authors present a new type of fine<br />
bubbles generator whose dispersion element of the air into the water<br />
mass is a metallic board of rectangular shape in which a number of holes<br />
is practiced. The holes were positioned in xoy coordinates and<br />
manufactured by electro-erosion. The fine bubbles generator was<br />
introduced in a water basin and included in the structure of an<br />
experimental stand; the results obtained from the experimental researches<br />
performed are exposed.<br />
Key words: fine bubbles generator, water aeration, electro-erosion<br />
processing.<br />
COMPARATIVE ENERGY AND EXERGY ANALYSIS OF THE<br />
ABSORPTION, RESORPTION AND COMPLEX ABSORPTION-<br />
RESORPTION SYSTEMS<br />
by<br />
ELENA EUGENIA VASILESCU, GHEORGHE POPESCU, CLAUDIA<br />
IONIŢĂ, VALENTIN APOSTOL and HORAŢIU POP<br />
Abstract. The paper deals with the energy and exergy analysis of<br />
the absorption, resorption and complex absorption-resorption<br />
thermodynamic cycles with ammonia-water as working fluid. A<br />
comparison between the analyzed cycles (working as refrigeration or<br />
heat pump systems) provides information about the opportunity to<br />
choose the most adequate schema as a function of the imposed design<br />
parameters.
Key words: absorption, refrigeration, heat pump, exergy, COP.<br />
ALLOCATION OPTIMALE DES ÉCHANGEURS DE CHALEUR<br />
DANS LES SYSTÈMES BOOTSTRAP EN BOUCLE OUVERTE<br />
DES AERONEFS<br />
par<br />
BOGDAN HORBANIUC et GHEORGHE DUMITRAŞCU<br />
Abstract. The open-loop bootstrap systems are driven by turbojet<br />
aircraft engines to cool the cabin and save energy. The aim of the paper<br />
is to optimize from the thermodynamic point of view the two heat<br />
exchangers (main and regenerative) of the bootstrap system. The<br />
optimization criterion is the minimum power extracted from the engine.<br />
The constraint is the limited capacity of heat exchangers to transfer heat.<br />
We developed a mathematical model of the system and we analyze the<br />
ideal case (reversible adiabatic compression and expansion).<br />
Key words: open loop system bootstrap, thermodynamic<br />
optimization, optimal allocation<br />
ANALYSE DES PERFORMANCES D’UNE POMPE À CHALEUR<br />
À ABSORPTION<br />
par<br />
DRAGOŞ HERA et CĂTĂLINA VASILESCU<br />
Abstract. The absorption heat pumps arise a growing interest<br />
among researchers because they can use renewable or inexpensive (heat<br />
recovery) energy sources. This paper presents a mathematical model<br />
recently developed by the authors to calculate the state parameters and<br />
process for the cycle of absorption heat pump with ammonia-water<br />
mixture. The model applies the conservation equations for mass and<br />
energy for each unit making up the installation. Using the computer<br />
program developed the performance of absorption heat pump with<br />
ammonia-water mixture is studied as a function of selected input<br />
parameters: the temperature of the heating agent and the temperature of<br />
the heat sink. It also analyzes the influence of these parameters on the<br />
temperature of hot water prepared.<br />
Key words: heat pump, absorption cycle, ammonia-water solution,
coefficient of performance<br />
WAVY FINS PITCH INFLUENCE ON WATER-AIR HEAT<br />
EXCHANGER PERFORMANCE<br />
by<br />
MIHAI NAGI, IOAN-DANIEL CĂRĂBAŞ and PAUL ILIEŞ<br />
Abstract. In this paper there is experimental research developed, on<br />
how does the pitch of sinuous fin, on the air side, influence the thermic<br />
transfer coefficient and pressure drop. The results have been generalized<br />
and the Colburn curves have been plotted according to Reynolds, and the<br />
friction coefficient according to Reynolds.<br />
Key words: fin pitch, heat changers, thermic transfer, Colburn,<br />
Reynolds.<br />
EXERGY ANALYSIS OF THE TRANSIENT REGIME OF<br />
VAPOUR COMPRESSION REFRIGERATION SYSTEMS<br />
by<br />
RAHAL BOUSSEHAIN, ELENA EUGENIA VASILESCU, YOUCEF<br />
ABDELLOUCHE, MICHEL FEIDT and ALEXANDRU<br />
DOBROVICESCU<br />
Abstract. This paper presents a method of analysis of the exergy<br />
destruction on each component of a vapor compression refrigeration<br />
system during the transient regimes of functioning. Using experimental<br />
data, one calculated the exergy destruction as a function of time under<br />
the influence of some factors that perturb the stationary regime, as the<br />
deactivation of a piston, the variation of the mass flow rate and of the<br />
initial temperature of the cooled fluid, the diminution of the compressor<br />
speed.<br />
Key words: exergy destruction, refrigeration, transient regime.<br />
SIMULATION OF A DOMESTIC ABSORPTION OF CHILLER<br />
by<br />
NADÈGE CHATAGNON, MARC BACHMANN,<br />
GUILLAUME ANIES and JEAN CASTAING-LASVIGNOTTES
Abstract. Liquid absorption tri-thermal refrigeration systems are<br />
particularly promising in solar cooling. Designed and sized in order to<br />
reply to nominal conditions, these machines are often submitted to<br />
varying operating conditions. Being able to predict their influences on<br />
the machine and the associated energy performance is revealing rather<br />
tricky. After a brief review of the operating principle, we present the<br />
experimental results obtained on a test bench where were applied various<br />
experimental conditions on a ROTARTICA Solar of 4.5 kW. In a second<br />
step, a model is developed to predict the chiller’s performance based on<br />
operating temperatures. To do this, the main parameters of the model<br />
have been identified thanks to three different tests and validated on other<br />
experimental results. The simulation’s results are in agreement with the<br />
measures. Finally the sensibility of the parameters identified is studied<br />
and discussed.<br />
Key words: modeling, identification, simulation, absorption.<br />
MODELISATION D’UN SYSTÈME DE RAFRAICHISSEMENT<br />
SOLAIRE PAR ABSORPTION UTILISANT (H 2 O – LIBR)<br />
by<br />
R. TOUAIBI, M. TAHAR ABBES, R. BOUSSEHAIN,<br />
M. FEIDT, E. VASILESCU, M. COSTEA et B. KHELIDJ<br />
Abstract. Absorption solar cooling is a very modern technology to<br />
cool a room by using a binary solution and a source of free heat using a<br />
solar collector. This paper will be devoted to the study of a system<br />
designed to cool via solar absorption using the mixture of lithium<br />
bromide-water (LiBr/H 2 O) with water as the refrigerant. The principle of<br />
operation is first introduced, and then the system modeling is presented.<br />
Modeling is an essential step in evaluating the potential of this technique.<br />
Models of the system components will be developed to perform the<br />
complete modeling of the system equipped with two types of solar<br />
collectors in order to improve its performance. The model can be used to<br />
provide a prototype for application in Algeria.<br />
Key words: cooling, absorption, solar, modeling, lithium bromide.<br />
ON PRESSURIZATION OF A COMPARTMENT DUE TO<br />
RUPTURE OF COOLANT PIPING IN A NUCLEAR POWER
PLANT<br />
by<br />
TEONA LOZONSCHI<br />
Abstract. Venting and pressurization of enclosed compartments due<br />
to the accidental rupture of coolant piping is a safety problem common to<br />
many nuclear facilities, mainly in a seismic event. The processes<br />
associated with such an accident are very complex, involving, in general,<br />
transient multiphase flows, interactions and mixing between the<br />
incoming flows and gases in the compartment, and heat transfer with<br />
surroundings. The objective of this paper is to present a simplified,<br />
global analysis approach which can provide reasonably conservative<br />
estimates of structural loads and flow processes, and which can be<br />
readily be used in design studies.<br />
Key words: pressurization, coolant piping, multiphase coolant<br />
flows, heat transfer, structural loads, flow processes.<br />
ANALYSE THÉORIQUE ET ÉXPERIMENTALE D’UNE<br />
MACHINE À FROID DE STIRLING<br />
by<br />
STOIAN PETRESCU, LAVINIA GROSU, MONICA COSTEA,<br />
PIERRE ROCHELLE, CĂTĂLINA DOBRE and CAMELIA PETRE<br />
Abstract. The paper presents a theoretical and experimental study<br />
of the reverse Stirling cycle applied to a β type machine. It is based on<br />
analytical models developed for refrigeration machines by using the<br />
methods from Finite Speed Thermodynamics (FST) and Finite Physical<br />
Dimensions Thermodynamics (FDT). The theoretical results are<br />
compared to experimental ones. The effect of the piston speed on the<br />
COP of the real operation machine is emphasized. Although the heat<br />
losses due to imperfect regeneration are differently evaluated, the two<br />
methods present similar performance variation.<br />
Key words: reverse Stirling cycle, finite speed thermodynamics,<br />
finite physical dimensions thermodynamics, direct method, irreversibility<br />
causes.<br />
PERFORMANCES D’UNE MACHINE FRIGORIFIQUE MUNIE
D’UNE DÉTENDEUR À EJECTEUR UTILISANT LES FLUIDES<br />
R134 ET HFO1234 yf<br />
par<br />
LATRA BOUMARAF, PHILIPPE HABERSCHILL et AHMED<br />
BENSAFI<br />
Abstract. A vapor compression refrigeration system using an<br />
ejector instead of a throttling valve to recover some of the kinetic energy<br />
of the expansion process is presented. A constant-area mixing model for<br />
the two phase flow ejector was developed. For typical air conditioning<br />
operation conditions, the effects of the ejector geometrical parameters<br />
and the pressure drop in the receiving section on the system performance<br />
were investigated. For a set ejector geometry, the condensation<br />
temperature influence on the ejector performance was also studied. The<br />
ejector model is then used to perform the thermodynamic analysis of the<br />
refrigeration system operating with the working fluids R134a and its<br />
potential substitute HFO1234 yf. The simulation results show an<br />
important improvement of the relative COP of the ejector expansion<br />
refrigeration system particularly when the condensation temperature<br />
increases (40% at 55°C for the two refrigerants). The results also show<br />
that HFO1234 yf leads to better performance than R134a when the<br />
condensation temperature decreases.<br />
Keywords: refrigeration system, ejector, R134a, HFO1234yf .<br />
REFROIDISSEMENT D’UN COMPOSANT ÉLECTRONIQUE<br />
PAR CONVECTION FORCÉE À L’AIDE DE DEFLECTEURS<br />
LONGITUDINAUX<br />
par<br />
AHLEM ARFAOUI OMRANI, REJEB BEN MAAD, MOURAD<br />
REBAY, COLETTE PADET and JACQUES PADET<br />
Abstract. The cooling of electronic components raises a great deal<br />
of research work, some of which was devoted to the influence of baffles<br />
meant to flow channeling [1]. Therefore, we propose an experimental and<br />
numerical study of the convective transfer of a heating element mounted<br />
on a flat plate placed at the entrance of a laminar flow of air with uniform<br />
velocity. Two longitudinal baffles mounted on the base of the heating<br />
element guide the flow onto it. The results obtained show the influence
of the angle of inclination and spacing of baffles in improving the<br />
convective heat transfer at the interface air-heater.<br />
Key words: cooling, electronic component, forced convection,<br />
longitudinal baffles.<br />
POST-COMBUSTION CO 2 CAPTURE FROM COAL-FIRED<br />
POWER PLANTS<br />
by<br />
VIORICA CEBRUCEAN, IOANA IONEL and DUMITRU<br />
CEBRUCEAN<br />
Abstract Post-combustion capture process involves the<br />
separation of CO 2 from the flue gas produced by combustion. The<br />
concentration of CO 2 in the flue gas of a typical coal-fired power<br />
plant is less than 15% (by volume) and the flue gas is present at<br />
almost atmospheric pressure. These two have a significant impact<br />
on the CO 2 capture process. However, post-combustion carbon<br />
capture is the most developed concept and has the greatest near- to<br />
middle-term potential for reducing CO 2 emissions, because it can<br />
be retrofitted to existing coal-fired power plants with only minor<br />
modifications. Chemical solvents are currently the most preferred<br />
option for post-combustion systems, offering a relatively high<br />
capture efficiency and selectivity. Three post-combustion systems<br />
are discussed and presented in this paper: amine-, carbonate- and<br />
ammonia-based process.<br />
Key words: CO 2 capture, post-combustion, amine/carbonate/<br />
ammonia-based process, coal-fired power plant.<br />
HEAT TRANSFER AT CONDENSATION OF A GAS-VAPOR<br />
MIXTURE IN AN ELECTRIC FIELD<br />
by<br />
MIRCEA BOLOGA, FEDOR GROSU, ALBERT POLICARPOV<br />
and OLEG MOTORIN 1<br />
Abstract. The results of experimental investigation of heat<br />
transfer at condensation of a gas-vapor mixture under the influence<br />
of a direct electric field are presented. At a noncondensable gas<br />
concentration of 5%, an approximately two-fold increase in the
coefficient of the heat transfer is obtained. The condensation<br />
process enhancement is explained by the combined effect of the<br />
condensate film turbulence and the decrease in the diffusion<br />
resistance of the noncondensable gas layer in an electric field. The<br />
results can be used for design of compact vapour condensers.<br />
Key words: heat transfer, condensation, electric field, noncondensable<br />
gas.<br />
ÉFFICACITÉS ET RENDEMENTS DES SYSTÈMES PILES À<br />
COMBUSTIBLE<br />
par<br />
A. VAUDREY, P. BAUCOUR, F. LANZETTA et R. GLISES<br />
Abstract. Its atypical nature – a "slow" combustion engine<br />
producing electrical work − makes the fuel cell system difficult to<br />
compare to a competing technology solution, consisting for<br />
example of a couple heat engine / electric generator. Its mode of<br />
isothermal operation complicates the comparison of its<br />
effectiveness with that of a normal thermal system operating<br />
between two temperature levels. To overcome this difficulty, we<br />
use equivalence between a fuel cell and an ideal Carnot engine, to<br />
which we add an internal generation of entropy due to electrical<br />
surges characteristic of a real fuel cell. The proposed analogy is<br />
then converted in the exergy model which not only allows a more<br />
meaningful comparison of the fuel cell with alternative energy<br />
solutions, but also a demonstration of its actual energy<br />
performance.<br />
Keywords: fuel cells, efficiency, exergy .<br />
MICROCOGÉNÉRATION : CHOIX DU MOTEUR THERMIQUE<br />
par<br />
PASCAL STOUFFS
Abstract. Micro-combined heat and power systems are gaining<br />
more and more interest for domestic use. Reflections on the choice of the<br />
thermal engine are presented.<br />
Key words: Micro-CHP, cogeneration, engine, Stirling, Ericsson,<br />
ORC.<br />
ENGINE AIR-CHARGE REGRESSION MODEL<br />
by<br />
DANIEL DINESCU and MOHAND TAZEROUT<br />
Abstract. A physically based regression model for predicting the<br />
intake flow in an IC engine is presented. The effect of the intake<br />
manifold conditions (pressure and temperature) and engine speed and<br />
geometry on the incoming mass flow-rate is considered. The proposed<br />
model is computationally simple and involves parameters that can be<br />
easily measured. It may be therefore suitable for engine control.<br />
Key words: internal combustion engine, intake mass flow rate,<br />
mean value modelling, regression model.<br />
UNE MODÉLISATION DU TRANSFERT DE CHALEUR ET DE<br />
MASSE AU SERPENTINES DE TUYAUX GAUFRÉS DES<br />
CHAUDIÈRES À CONDENSATION<br />
par<br />
DAN PAUL STĂNESCU, NICOLAE N. ANTONESCU<br />
et NICULAE ANTONESCU<br />
Abstract. Heat and mass transfer modeling for goffered tubes<br />
used for condensing boilers. A very efficient constructive solution<br />
for condensing boilers with serpentine pipe is based on the use of<br />
goffered tubes. The boiler’s particularity is the construction with<br />
only one continuous serpentine pipe placed vertically in the boiler.<br />
For the final whirls the heat transfer is represented by both latent<br />
and sensible convection from the flue gases. For this specific<br />
constructive solution, a numerical model was developed, based on<br />
several physical models for heat and mass transfer over condensing<br />
surfaces. The numerical model was finally verified through<br />
laboratory experimentations on real goffered tubes, single<br />
serpentine pipe, condensing boilers of 30 and 100 kW. The<br />
measured parameters were in good agreement with those obtained
from the computational model, fact that validated the numerical<br />
model and the comprised hypothesis. The validation was obtained<br />
not only for nominal functioning regime but also for partial loads<br />
and for the whole range of inlet water temperatures used for the<br />
boiler.<br />
Key words: condensation boilers, goffered tubes, heat transfer.<br />
MESURES DE LA PRESSION INSTANTANÉE DANS UN<br />
COMPRESSEUR À PISTON ET COMPARAISON AVEC DES<br />
RÉSULTATS THÉORIQUES<br />
par<br />
DAN ANDREI<br />
Abstract. The resolution of the six first order and second order<br />
differential equations (two first order equations and four second-order)<br />
that make up the mathematical model of a pulsating pressure compressor<br />
operation [1], [2], [3] is made by the Runge-Kutta fourth order method.<br />
Variation diagrams of pressure in the compressor cylinder, of the total<br />
pressure in the pressure chamber and of the displacement of the<br />
discharge valve were obtained for three operating regimes with<br />
compression ratios: H1 = =3.4, H1 = 4.5 and H1 = 5.6.<br />
Key words: acoustics, pulsating pressure, reciprocating compressor.<br />
ENERGY RECOVERY OF COMBUSTIBLE GASES FROM<br />
GEOTHERMAL WATERS BY COGENERATION UNITS WITH<br />
INTERNAL COMBUSTION ENGINES<br />
by<br />
ANA-MARIA BIANCHI, SORIN DIMITRIU and FLORIN<br />
BĂLTĂREŢU<br />
Abstract. In some geothermal fields, the hot water is associated<br />
with high content hydrocarbons gases, especially methane. These gases,<br />
which can reach to a content of 2…2.5 m 3 N per cubic meter of water and<br />
can have a methane content of 85…90%, represent an important power<br />
potential. This paper presents the possibility of power potential recovery<br />
of these gases using gas engine cogeneration units. A case study is<br />
performed, regarding the geothermal water wells working in
Calimanesti- Caciulata - Cozia zone, on the Olt Valley. An important<br />
power potential about 3.6 MW is pointed out, (1.4 MW electric power<br />
and 2.2 MW thermal power). The electricity may be locally consumed or<br />
injected in the electric grid, while the thermal energy can be delivered to<br />
residential consumers.<br />
Key words: cogeneration, gas engine unit, geothermal district<br />
heating.<br />
COMPUTATIONAL MODELLING OF THERMAL STRESSES IN<br />
THE COMBUSTION CHAMBER OF A SPARK IGNITION<br />
ENGINE FUELED WITH ETHANOL-GASOLINE BLENDS<br />
by<br />
KRISZTINA UZUNEANU 1 and EUGEN GOLGOŢIU<br />
Abstract The thermal stresses in the combustion chamber of<br />
an internal combustion engine are determined as a function of the<br />
level of temperature. Measuring the temperatures in different parts<br />
of the piston and cylinder head, we can adjust the cooling, or we<br />
can improve the materials, or even we can improve the properties<br />
of the fuels. The present paper deals with the thermal stresses in the<br />
combustion chamber of a spark ignition engine fueled with a blend<br />
of gasoline with ethanol.<br />
Key words: piston head, cylinder head, thermal stress, ethanolgasoline.<br />
COMPUTER SIMULATION OF NONSTATIONARY FLOW<br />
THROUGH THE TURBOCHARGER UNIT CHARGE<br />
OF SUPERCHARGED DIESEL ENGINES<br />
by<br />
SALVADORE MUGUREL BURCIU<br />
Abstract. This paper presents the mathematical model behind the<br />
computer program, which allows simulation of nonstationary flow<br />
through the compressor unit of charge with free rotation of supercharged<br />
diesel engines. Phoenics software program developed by using personal<br />
subroutines can be used to simulate the nonstationary flow through the<br />
turbocharger VTR 200R of MB836 Db turbocharged diesel engine. In the<br />
paper are presented in graphical form, some results obtained for 3D nonstationary<br />
flow through the turbocharger compressor rotor.
Key words: supercharged engine, computer simulation, Phoenics<br />
software.<br />
A NEW SOLUTION TO IMPROVE THE CONTACT<br />
CONDITIONS IN THE DISTRIBUTION SYSTEMS OF THE<br />
INTERNAL COMBUSTION ENGINES<br />
by<br />
GHEORGHE MANOLACHE, EDWARD RAKOŞI, RADU ROŞCA<br />
and SORINEL TALIF<br />
Abstract. The paper presents the results of an analysis concerning<br />
the main factors affecting the cam-follower contact conditions,<br />
emphasizing the influence of the lubrication regime conditions over the<br />
couple wear reduction; an original technical solution is proposed and<br />
studied for the improvement of the lubrication regime and engine life, in<br />
order to preserve the engine performances and pollution level.<br />
Key words: contact conditions improvement, distribution systems,<br />
internal combustion engines.<br />
EXPERIMENTAL VALIDATION OF A NUMERICAL METHOD<br />
FOR CALCULATING PORT INJECTION<br />
AIR-FUEL MIXTURE STATE PARAMETERS<br />
by<br />
ADRIAN IRIMESCU, DĂNILĂ IORGA, LIVIU MIHON and IOAN<br />
HITICAŞ<br />
Abstract. Air-fuel mixture formation in port injection spark<br />
ignition engines is a complex process of heat and mass transfer. Intake<br />
air is mixed with pulverized gasoline that follows a multi-stage process<br />
in which the liquid is broken into small size droplets and then evaporates.<br />
How much fuel actually evaporates depends on various conditions such<br />
as manifold pressure, air temperature and relative humidity, as well as<br />
air-fuel ratio. Experimental results obtained during measurements with a<br />
time span of one year confirm the validity of the numerical method<br />
developed for calculating air-fuel mixture state parameters. Measured<br />
mixture temperature values are very close to the results obtained through
calculations, with a maximum error slightly over 10 %, as the difference<br />
between the two values compared to the range of -20…40 °C.<br />
Key words: spark ignition engines, heat and mass transfer, air-fuel<br />
mixture, intake.<br />
IRREVERSIBLE SEMI-DIESEL CYCLE APPROACH BASED ON<br />
THE DIRECT METHOD FROM FINITE SPEED<br />
THERMODYNAMICS<br />
by<br />
STOIAN PETRESCU, NICOLAE BORIARU, CRISTIAN LEONTIEV,<br />
MONICA COSTEA and CAMELIA PETRE<br />
Abstract: The paper presents a Direct Method Approach for<br />
estimating the performances of the irreversible Semi-Diesel Cycle,<br />
with finite speed. The irreversibility generated by the finite speed<br />
of the processes, the throttling losses at intake and exhaust and the<br />
friction losses was determined. The influence of the piston speed,<br />
the pressure increase and cut-off ratio at combustion was studied,<br />
too. The results show optimum values of the piston speed and other<br />
parameters (α and λ) of the model for Maximum Power Regime.<br />
Key words: semi-Diesel, cycle performances, finite speed<br />
thermodynamics, direct method, irreversibility causes.<br />
ÉTUDE THERMODYNAMIQUE DE L’INFLUENCE DE LA<br />
PRESSION DE CHARGE INITIALE SUR L’AMELIORATION<br />
DES PERFORMANCES D’UN MOTEUR STIRLING DE TYPE<br />
GAMMA<br />
par<br />
RAMLA GHEITH, FETHI ALOUI, MOHAND TAZEROUT<br />
et SASSI BEN NASRALLAH<br />
Abstract. In this paper, the classic adiabatic model was adopted. In<br />
this model, the assumption of perfect working fluid was replaced by the<br />
assumption of real one. The real gas was defined by the Van der Waals<br />
state equation. In fact, the influence of real gas appears for ‘important’<br />
pressures. So, we have introduced the concept of “filling initial<br />
pressure”. To check the validity of the developed model, a Gamma kind
of Stirling engine, functioning with initial filling pressures, was used to<br />
carry out experiments. We have finally, validated the results obtained by<br />
the model with experiments.<br />
Key words: Stirling motor, pressure of remplisage, adiabatic model,<br />
amelioration.<br />
RECOVERY OF ORGANIC WASTE IN THEIR RECYCLING IN<br />
AGRICULTURE<br />
by<br />
ILINCA DINU and OANA GHEORGHIŢĂ<br />
Abstract. Currently, worldwide, household and industrial<br />
activities of population from urban centers produce large quantities<br />
of solid and liquid waste. From all these wastes the most aggressive<br />
towards the environment are those of organic nature, because of<br />
their rapid fermentation resulting a massive air and soil pollution.<br />
From this category of waste are the organic sludge resulted from<br />
the wastewater treatment process in urban cleaning stations.<br />
Considering the requirements of the European environmental<br />
protection rules that have been imposed by the restrictions of<br />
current legislation, the authors of this paper deals with some<br />
innovative aspects of waste recycling, on the one hand to protect<br />
the environment, and on the other hand to exploit mineralized<br />
organic waste as organic fertilizer in agriculture.<br />
Key words: waste, sewage sludge, capitalization.<br />
SOME EXPERIMENTAL ASPECTS OF BIOMASS BURNING<br />
by<br />
MANUELA ELENA GEORGESCU, LUCIAN MIHĂESCU, IONEL<br />
PÎŞĂ, TUDOR PRISECARU, ION OPREA and GABRIEL<br />
NEGREANU<br />
Abstract. The paper purpose is to present some of the<br />
problems appearing in boilers when burning biomass. The specific<br />
burners for the specific fuel, the fuel preparation technology and<br />
the experiments achieved on pilot and industrial boilers are<br />
presented in the paper.<br />
Key words: biomass, burner, composite briquettes, boiler.
UTILISATION SIMULTANÉE DE CHALEUR ET DE FROID EN<br />
INDUSTRIE AGRO-ALIMENTAIRE, À L'AIDE DE MACHINES<br />
À COMPRESSION MÉCANIQUE DE VAPEUR : QUEL<br />
CRITÈRE D'EFFICACITE?<br />
par<br />
RAHAL BOUSSEHAIN, DIMITER DIMITROV et MICHEL FEIDT<br />
Abstract. A double use thermofrigopump vapour compression<br />
machine model is proposed in the present paper. This model is relative to<br />
steady state irreversible system, and takes account of finite size<br />
constraint through the heat transfer laws. Thermodynamical efficiencies<br />
of this system has been defined and compared. The corresponding<br />
optimization results are proposed.<br />
Key words: hydrogen, HRG, thermal cutting.<br />
VALORISATION DES GRAISSES ANIMALES COMME<br />
BIOCOMBUSTIBLE POUR MOTEURS DIESEL<br />
par<br />
NADIA MRAD, FETHI ALOUI, MOHAND TAZEROUT,<br />
SASSI BEN NASRALLAH et HASSEN ABDALLAH<br />
Abstract. In this work, we aim at studying the recovery of beef<br />
fat by the technique of pyrolysis to produce a biofuel for diesel<br />
engines. The goal is to monitor the performance and the acidity of the<br />
final liquid fuel (pyrolysis oil) and to identify the various noncondensable<br />
gases released.<br />
Key words: Animal fat, pyrolysis, catalytic cracking, bio-fuel,<br />
acidity.<br />
STUDY OF BIODIESEL OBTAINED THROUGH<br />
VALORIFICATION OF BIOMASS<br />
by<br />
CAMELIA CIUBOTĂ-ROŞIE, LAURA BULGARIU, CEZAR<br />
CATRINESCU, IRINA VOLF and MATEI MACOVEANU
Abstract. This paper studies the method of obtaining biodiesel from<br />
mustard seeds (Sinapis Alba). Obtaining oil from oils seeds are made by<br />
mechanical pressing, through solvent extraction and the extraction in<br />
super critical condition with CO 2 . The paper presents the process of<br />
extraction with solvents of the oil from mustard seeds. It was studied<br />
the extraction of oil with seven types of solvent in the same conditions<br />
of extraction (n-hexane, cyclohexane, heptanes, petroleum ether, ethyl<br />
acetate, acetone and tetrachloride of carbon) and the results were<br />
compared to identify the best solvent, considering the cost of the solvent<br />
and the environmental impact. After the oil extraction it was analyzed<br />
the composition of each type of oil extracted with a certain solvent to<br />
determine the optimal conditions for administrating the process of<br />
transesterification of the oil obtained. It was also determined the<br />
characteristics that the vegetable oil must fulfill before the<br />
transesterification process according to the 14 214 standard.<br />
Key words: biomass, biodiesel, mustard seeds, solvents extraction<br />
INFLUENCE OF ELECTROPLASMOLYSIS AND THERMAL<br />
TREATMENT ON QUALITATIVE PROPERTIES OF<br />
VEGETABLE RAW MATERIALS<br />
by<br />
NATALIA POPOVA, ANDREI PAPCHENKO and MIRCEA<br />
BOLOGA<br />
Abstract: The results of the experimental investigations of the<br />
electroplasmolysis and thermal (frying in the vegetable oil of the marrow<br />
and carrot) treatment influence on their technological indexes are<br />
presented. It is shown that electroplasmolysis due to increasing of the cell<br />
permeability accelerates the process of frying, decrease the oil saturation<br />
capacity, that leads to decreasing of its specific consumption per unit of<br />
stock production. It was found that the acid number of the vegetable oil<br />
decreases while the iodine number increases insignificantly.<br />
Key words: electroplasmolysis, thermal treatment, vegetable raw<br />
materials, qualitative properties.<br />
RECHERCHES EXPÉRIMENTALES CONCERNANT LE<br />
PROCESSUS DE SÉCHAGE DES CÉRÉALES À DOUBLE<br />
SOURCE D’ÉNERGIE<br />
par
CORINA DANA CERNĂIANU et MARIN BICĂ<br />
Abstract. The desiccation of plants requires large energy<br />
consumption. In the proposed drying method traditional heating<br />
can be replaced by solar heating. We present the experimental<br />
research performed to achieve the drying process in cereal seeds<br />
drying equipment with dual heating source.<br />
Keywords: drying process, seeds drying, solar heating.<br />
ELECTROPHYSICAL METHODS FOR RECYCLING OF THE<br />
SECONDARY MILK PRODUCTS<br />
by<br />
MIRCEA BOLOGA, ELVIRA SPRINCEAN, ALEXANDRU<br />
BOLOGA, ALBERT POLIKARPOV and TATIANA STEPURINA<br />
Abstract. Electrophysical methods are some of the most effective<br />
for processing protein-carbohydrate milk raw materials. In this paper the<br />
electroactivation of initial whey was used with a subsequent recovery of<br />
a protein-mineral concentrate as well as of deproteined whey for lactose<br />
processing. The proposed method of electrofractionation of secondary<br />
milk raw materials is found to be a reagentless, low-temperature process<br />
and it can be included in a wasteless recycling of whey aimed at the<br />
production of protein-mineral concentrate and lactose and lactulose<br />
products.<br />
Key words: secondary milk products, protein-mineral concentrate,<br />
lactose and lactulose products.<br />
ASPECTS REGARDING THE DESIGN OF A ROTARY DRYER<br />
FOR AN EQUIPMENT WHICH COMPRESSES SAWDUST<br />
by<br />
PETRE RĂDUCANU<br />
Abstract. The wood wastes, resulting from the forest exploitation<br />
and from the wood processing, have to be very carefully treated, in<br />
order not to produce a huge pollution. These wood-refuses have to be<br />
turned, through drying and compression, into burning woodbricks,<br />
which can be used for energetical purposes. For this reason was design<br />
a mobile equipment, in which, a dryer used for the diminishing of the<br />
sawdust humidity, was integrated. The paper presents the way in
which the dryer was designed. There are presented the results got and<br />
the analysis of the factors which influence the design.<br />
Key words: sawdust drying, dryer design.<br />
HEATING AND COOLING SOLUTIONS OF NEW<br />
RESIDENTIAL AND OFFICE BUILDING DISTRICTS IN<br />
SUSTAINABLE DEVELOPMENT CONTEXT<br />
by<br />
SEVERIN CĂZĂNESCU1 and RALUCA ALEXANDRA<br />
CĂZĂNESCU<br />
Abstract. The paper present a case study analyzed for an area<br />
of 50 hectares in Bucharest, where office and residential buildings<br />
are intended to be built. There were studied classical solutions for<br />
heating and cooling of the buildings in comparison with coupled<br />
solutions combining boiler and cooling plants with solar systems<br />
and trigeneration. The different solutions were analyzed both from<br />
technical and economic point of view, taking into consideration the<br />
site development and the necessary resources to be involved.<br />
The proposed solution to be achieved is to produce electrical<br />
and thermal energy in trigeneration plants coupled with<br />
heating/cooling substations at building level and to use solar<br />
energy in combination with classic boiler plants for the buildings<br />
which are not connected to the trigeneration systems.<br />
Key words: sustainable development, trigeneration, solar<br />
energy, environmental protection.<br />
AN INNOVATIVE SOLUTION FOR CLEAN TERRESTRIAL<br />
PROPULSION: SMALL SCALE COMBINE CYCLE UNIT<br />
PERFORMANCE EVALUATION<br />
by<br />
DAN-TEODOR BĂLĂNESCU and MARIO-VLAD HOMUTESCU
Abstract. The Gas-Steam Combined Cycle Units are the actual<br />
leader in the domain of high and medium power generation systems. As<br />
long the heavy ships propulsion systems have powers in this range, the<br />
use of the Combined Cycle Units for naval propulsion was not only<br />
possible but completely successful. This justify the study of the<br />
possibilities to develop Small Scale Combined Cycle Units, properly<br />
even for the propulsion of the heavy lorries. In the present paper, the<br />
results of a study regarding the performances of a Small Scale Combined<br />
Cycle Units are presented. The configuration of this unit can be a<br />
properly one for the propulsion system of the heavy lorries.<br />
Key words: combined cycle, small scale, terrestrial propulsion,<br />
Heller condenser system, high efficiency.<br />
ESTIMATION DU FACTEUR DE DETERIORATION DES<br />
EMISSIONS POLLUANTES POUR LE PARC D’AUTOMOBILES,<br />
EN FONCTION DE L’AGE ET DU NOMBRE DE KILOMETRES<br />
PARCOURUS (KILOMETRAGE)<br />
par<br />
KRISZTINA UZUNEANU 1 , DAN DRĂGHIA 1 et EUGEN<br />
GOLGOŢIU 2<br />
Abstract. The emission factor is defined in this section as a factor<br />
which, multiplied with the amount of pollutants emitted by a new engine,<br />
allows the estimate with reasonable accuracy of the amount of pollutants<br />
(CO, HC, NOx) emitted by the engine after a certain number of years and<br />
a certain mileage. The deterioration factor of the emissions has been<br />
determined by using a rich database of pollutant emissions from certain<br />
engines grouped based on their displacement and degree of treatment of<br />
exhaust gases in accordance with European standards (Euro I ..EuroV)<br />
Key words: automobile pollution, emission deterioration, factor for<br />
automobile pollution.<br />
DÉTERMINATION DE LA CONDUCTIVITÉ THERMIQUE<br />
DANS LES MATÉRIAUX DE CONSTRUCTION<br />
par<br />
MONICA CHERECHEŞ, CĂTĂLIN POPOVICI<br />
et NELU-CRISTIAN CHERECHEŞ<br />
Abstract. Using an unsteady heat transfer method, the<br />
thermophysical properties of the three building materials were
experimentally determined. The evolution of contact temperatures versus<br />
time, for each material, indicates an early rapid decrease in temperature,<br />
followed by a slight increase during 2-3 minutes. Then, the contact<br />
temperature is stabilized to a value that remains constant for a period of 3<br />
to 7 minutes, quite long enough to measure the temperature of contact. In<br />
addition, we performed numerical simulations in variable regime using<br />
the NASTRAN ® software to determine the temperature distribution in<br />
the contact area.<br />
Key words: building materials, thermal conductivity, humidity,<br />
temperature of contact, simulation.<br />
RESEARCH AND STUDIES ON ENERGY EFFICIENT<br />
SOLUTIONS FOR ENVIRONMENTAL PROTECTION IN THE<br />
HEATING AND COOLING SYSTEMS FOR SCIENTIFIC<br />
RESEARCH LABORATORIES OF THE UNIVERSITY CAMPUS<br />
BRAŞOV<br />
by<br />
IOAN CĂLDARE<br />
Abstract: Starting from the basic ideas of the conception and design<br />
of buildings with low energy consumption, using non-conventional<br />
energy, research and studies refer mainly to: The capture and use of the<br />
soil heat in heat pump installations: 2 reversible heat pumps for each of<br />
the 12 scientific research laboratories. Were studied three variants of<br />
geothermal collectors: surface geothermal horizontal collector (h = 1.5<br />
m), small depth vertical geothermal collector type spiral drill (h = 5m),<br />
and geothermal probe of great depth (h = 100 m). Heating and cooling<br />
installations for all 12 laboratories by radiating surfaces: concrete<br />
tempered, semi tempered and floor heating.<br />
By coupling installation of heat pumps with heating and cooling<br />
systems of the laboratories of scientific research results that about 65-<br />
70% of annual energy for heating and cooling of a scientific research<br />
laboratory is provided by unconventional energy sources.<br />
Key words: heat pump, solar panel, collector geothermal,<br />
heating/cooling, radiant surfaces.<br />
STRUCTURES ET ADAPTATION PEDAGOGIQUES DANS LA<br />
CONSTITUTION D’UNE SPECIALISATION DE GÉNIE
MECANIQUE: SYSTÈMES ET ÉQUIPEMENTS THERMIQUES<br />
(SET)<br />
par<br />
MIRCEA IVĂNOIU<br />
Abstract. The study includes Principles of a flexible technical<br />
education, References to the criterion of temporal sequence of<br />
subjects, rational and natural, to provide a logical and robust<br />
construction of the qualification, Review of external pressures and<br />
constraints, in particular the labor market’s demand and the<br />
requirements of a modern and efficient top technical qualification<br />
program, including : Increasing domestic and international interuniversity<br />
mobility, Labor force mobility, Resilience of the<br />
professional training, Weight of the non-scientific education and<br />
the economic and managerial training component of a curricula,<br />
Component of a integrated perspective (Sustainable Education or<br />
Education for Sustainable Development) and specific relationship<br />
with the environment ( environmental protection in the field of<br />
industrial activity), Valences of humanities education. Conclusions<br />
of this work aimed to establish the unavoidable commandments in<br />
such a project, separating the elements of stability, universal, of the<br />
cyclical whose share would be drastically reduced.<br />
Key words: thermo systems and equipment, sustainable<br />
education, professional curricula, educational principles,<br />
mechanical engineering training.