Post-doctoral Programmes
Nine post-doctoral programmes are running in the centre, starting with 2010. The subjects were complementary formulated to give coherent and complex answers to some of the most important issues faced in implementing sustainable communities. Implementing renewable energy systems in the urban area requires customised, efficiency-optimised, feasible and market-accepted solutions. New or refurbished houses impose different problems but both should be considered.
Therefore, the post-doctoral programmes approach renewables implementation (photovoltaics, solar-thermal arrays), building and construction materials, and environmental solutions for wastewater treatment.
This integrated approach characterises all the 44 post-doc programmes, running in the centres within the RTD Institute of the Transilvania University.
The post-doctoral programmes are financed from the Structural Funds’ Project, POS-DRU, no.59323, and cover the 2010 -2013 period.
Post-doctoral Programmes
Title:
Modelling the energetic
efficiency in tracked photovoltaic platforms
Mentor:
Prof. Dr. Eng. Ion VISA
Post-doc researcher:
Dr. Eng. Mihai COMSIT
Time frame:
2010 -2013
Aim:
Modeling the energetic efficiency in photovoltaic systems by integration of specific models and corrections able to estimate the efficiency of the system in the
specific conditions of
implementation.
The validation of the model is will be validated by using an infield implemented testing platformand the model will be used is selecting and designing of optimal photovoltaic systems for the customer. The research is focused on:
- conceiving an development of a theoretical model of energetic efficiency of the photovoltaic systems;
- development of the software platform;
- design, development and
implementation of the testing platform;
- testing of the software platform and validation of the platform.
The efficiency variation of 4 types of PV panels: PolySI, MonoSI, AmorphousSi and CIS
Title:
Sequential algorithm for photovoltaic oriented systems
Mentor:
Prof. Dr. Eng. Dorin DIACONESCU
Post-doc researcher:
Dr. Eng. Bogdan BURDUHOS
Time frame:
2011- 2014
Aim:
The increase of the energetic efficiency for individual photovoltaic systems oriented with mechatronic mono-axial and biaxial systems, by replacing the annual fixed tracking programs with programs that consider and adapt themselves to the influences of the external meteorological parameters;
The research focuses on:
- identifying a model for forecasting the tracking efficiency according to the meteorological conditions of the implementation location and to the used orientation program; - definiing a program set for several
meteorological conditions; the optimization of the tracking program and its implementation in an improved control system; the identification of a selection method of the best fitted program set to the actual meteorological situation; - constructive optimization of the
tracking system in the condition of eliminating one orientation axis. - modelling of the dependence
between the optimal incidence angle and the direct/diffuse solar radiation, which leads to a orientation program according to the external sunshine conditions.
-80 -60 -40 -20 0 20 40 60 80 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time [h] A n g le [ d e g ] β_B* β_Gmax* β_Gmax* steps γ_Gmax* fix
Variation of the tracking system stepwise angles for a monoaxial orientation system
Variation of the tracking efficiency in the northern hemisphere
Title:
New photovoltaic cells adapted to the climatic environmental
conditions
Mentor:
Prof. Dr. Eng. Anca DUTA
Post-doc researcher:
Dr. Alexandru ENESCA
Time frame:
2010 - 2013
Aim:
Develop new materials that can be used as components for a solid state solar cell adapted to Brasov climatic environmental conditions. Using a 10kWp photovoltaic system was possible to record, evaluate and test the conversion efficiency at different temperature, direct and total solar radiation.
Compared with other months, including summer season, April has the most favorable climatic potential for photovoltaic conversion in the Brasov area.
Also, the distribution of the energy production in April shows that the last week of the month offered conditions for the highest conversion efficiency. New equations were tested to evaluate the module temperature.
Energy production in 2009 and detailed energy production in each April weeks
Title:
Robotic technologies to deposit thin films by spray pyrolysis in
open environment
Mentor:
Prof. Dr. Eng. Catalin ALEXANDRU
Post-doc researcher:
Dr. Eng. Monica Loredana ENESCU
Time frame:
2010 - 2013
Aim:
The main goal pursued is to achieve spray pyrolysis deposition technology using an industrial robot.
The optimization of spray pyrolysis deposition process is made by control characteristic parameters of deposited thin films on a flat surface or surfaces with variable geometry. The deposition is accomplished in an open environment characterized by low humidity. The objective is to generate various paths on the planar and curved surfaces.
It was developed the multi-body system (MBS) model for the mechanical structure of a robotic system with 6 degrees of freedom, using the MBS environment ADAMS.
The motion laws (positions and velocities) in the revolute joints of the robotic system, for generating the kinematically prescribed behaviour (the trajectory of the end-effector), through the inverse kinematic analysis were developed.
It was developed the control system model of the robotic system, using the DFC (Design for Control) environment MATLAB/Simulink; this is a multi-loop control (in-cascade configuration, with position, velocity and current loops). It was developed the virtual prototype of the robotic system by integrating, in mechatronic concept, the MBS model and the control system
Title:
Thin films with photocatalytic properties for advanced treatment of wastewater from textile industry
Mentor:
Prof.Dr. Lucia DUMITRESCU Post-doc researcher: Dr. Luminita ANDRONIC Time frame: 2010 - 2013 Aim: Development of photocatalytic materials in thin layers and related technology for advanced treatment of complex wastewaters containing dyes, surfactants and heavy metals. Photocatalytic materials obtained were: a. Titanium dioxide powder obtained by sol-gel method,
b. Copper sulphide powders obtained by photochemical precipitation used to obtain hybrid photocatalysis CuxS/TiO2 by
doctor blade method, sensitive to visible light.
Nanocrystalline TiO2 catalysts with
different contents of anatase and rutile phases were obtained by sol gel method. The sol-gel synthesis route resulted in TiO2 with good structural properties such
as homogeneity, controlled pore size distribution, and high porosity as well as enhanced catalytic properties. Anatase phase was found to be the unique phase in the samples annealed below 500ºC. Phase transformation of anatase into rutile was only observed in the sample synthesized by the sol-gel method when annealing at/above 600°C.
The CuxS/TiO2 hybrid photocatalysts
activated with H2O2 exhibited a higher
catalytic efficiency (99%) for dyes degradation comparing to the mono-component films.
Schematic diagram of charge transfer process in photocatalyst system CuxS/TiO2
20 30 40 50 60 70 80 1000 2000 3000 4000 5000 6000 7000 8000 9000 Mullite (2) (1) (Na,K,Ca)5Al6Si30O7218H2O Hematite Na6Al6Si10O3212H2O Na6[AlSiO4]64H2O SiO2cristobalite Al2O3γ,ε Hematite αSiO2quartz FA-Z FA-W In te n s it y [ a .u .] 2 theta [degree] Title:
Fly-ash based substrates for industrial waste water treatment
Mentor:
Prof. Dr. Eng. Anca DUTA
Post-doc researcher:
Dr. Maria VISA
Time frame:
2010 - 2013
Aim:
The aims to develop complex solution based on modified fly ash for advanced wastewater treatment with complex pollutant load.
Fly ash is modified for avoidng contamination by leaching and for enhancing the surface properties.
Further on, the research is focused on fly ash deposition on different substrates/ materials, to be used for wastewater treatment in fix bed adsorption and testing the solution for technological transfer. The removal efficiency of dyes and heavy metals is evaluated and theconcurrent processes in multi-pollutant waters is discussed.
The process control will be adapted for different industrial wastewaters having complex load: heavy metals, dyes, surfactants.
The substrates based on fly ash from CPH and from burning fast-growing biomass proved high adsorption capacity.
Modified substrate structure
Raw fly ash
Patent BOPI 6/2011, Isothermal heat plate working on the heat pipe operation principle
New colored solar absorbers / colored glazing
Title:
Materials with tailored properties for increasing the efficiency and
adaptability to the built
environment of flat plate solar thermal collectors
Mentor:
Prof. Dr. Eng. Anca DUTA
Post-doc researcher:
Dr. Mihaela DUDITA
Time frame:
2010 – 2013
Aim:
To develop novel spectral selective coatings, with high efficiency, adapted for urban integrated solar thermal flat collectors
Main objectives:
- developing an innovative heat plate for obtaining modular or large scale solar selective coatings; the heat plate will be isothermal by using the advantages of the heat pipe model; - obtaining colored thin films directly
on the absorber selective layer or as glazing coatings;
- integrating the result in a new prototype of solar collector
Title:
Development and optimisation of a solar dish collector used for heating/ cooling
Mentor:
Prof.Dr. Eng. Ion VISA Post-doc researcher:
Dr. Eng. Daniela CIOBANU
Time frame:
2010 - 2013
Aim:
Development and optimization of a solar thermal system used for heating / cooling integrated in the built environment using solar dish collector with biaxial tracking system.
The conceptual design of a solar thermal system with dish solar collector used for heating is based on the Brasov weather data and on a set of requirements targeting efficiency and effectiveness. The conceptual solution was obtained using the Frisco formula and consists of a set of variants, depending on the weight assigned to each criterion. When considering the tracking angles as the most important criterion, the conceptual solution the tracking solutions involves a linkage and gear mechanism whereas considering the costs, the recommended solution is based on a chain transmission.
The solar thermal system with solar dish collector which uses linkage and gear tracking system has the following advantages: simple construction and high fiability; the driving motor used is low cost (linear actuator); the precision for the angular orientation is higher; large range for the angular orientation (240 0); high efficiency; allows self-locking. The disadvantages for this tracking system are:
high gauge; require precision
Title:
New ecological processes of obtaining second raw materials from cellulose wastes
Mentor:
Prof.Dr. Silvia PATACHIA Post-doc researcher:
Dr. Catalin CROITORU
Time frame:
2010 -2013
Aim:
The aim of the postdoctoral program is to find alternatives to replace traditional solvents from cellulose wastes processing industry with less expensive, energy-consuming and more ecological solvents, such as ionic liquids.
Ionic liquids are a group of new organic salts that exist as liquids at a relatively low temperature (<1000C). They have many attractive properties, such as chemical and thermal stability, non-flammability and low vapor pressure. In contrast to traditional volatile organic compounds, they are called ‘‘green’’ solvents and have been widely used in lignocellulosic materials dissolution studies.
The solubility of various cellulosic materials (wood sawdust, paper, textile fibers) in alkylimidazolium-based ionic liquids are determined as a function of temperature, structure of ionic liquid and cellulosic material particularity (cellulose polymerization degree, humidity, oxidation degree). Starting from cellulose dissolved in ionic liquids as raw material, new multifunctional materials starting from cellulose or its derivatives with potential applications as construction materials are obtained. The properties of these materials are modeled and optimized as a function of synthesis parameters (temperature, composition) for different selected applications.
Cellulose solution in ionic liquids
