Stage III/2020 - Research Institute for Renewable Energies

Stage 3

The results obtained in the 3rd stage of the complex project were achieved in all component projects, the indicators being accomplished for each activity separately, in accordance with the work plan adapted to the financing period.

Component 1 project, included calibrations of the material models, performed in order to characterize the materials mechanical behavior. Thus, in a first step, fatigue tests were performed on polyurethane foam specimens required for sinusoidal loading cycles, proving that fatigue resistance is obtained for foam with lower density (145 kg/m3). Another study of this stage was the estimation of the cellular materials breaking tenacity by establishing micromechanical models, correlated with a statistical interpretation of the experimental results. They demonstrated that the tensile strength of PUR-type foams can be considered material characteristic regardless of the specimens’ type and tests, the main influence on the tensile strength being the cellular material density. The studies were completed by simulating the polystyrene plates impact behavior, using finite element analyzes. The calibration of the numerical model based on the experimentally obtained results confirms the validity of such studies and certifies the validity of the parameterized results.

Component 2 project activities were focused on the characterization of materials used for air pollutants degradation and the reduced absorption / reflection of UV-VIS-IR radiation. In a first phase, the comparative analysis of the thermally insulating materials used for solar facades, allowed the identification of the optimal materials for the thermal systems designed for buildings on metallic structure. The experimental analyzes were realized using specific conditions for the commercial cellular glass samples coated with investigated layers by simulated solar radiation exposure using an ORIEL SOL-2A device. Thus, the thermal performances were determined both for the uncoated samples and for each layer of paint applied. In addition, morphology by 3D laser microscopy and optical properties by spectral reflectance and RGB values of surfaces were analyzed. The results showed that the temperature in the 5 monitored regions decreases as the solar radiation passes through the exposed samples. The upper surface temperature for the cellular glass reached 78-80 ° C decreasing to 39-42 °C on the inside while for the sample P4_WO3 the temperatures reached are 76-81 °C on the outside and 36-37 °C on the inside. The reflectance analysis on the unpainted and painted cellular glass showed that the photocatalytic activity intensifies with the increase of the irradiated surface. The use of TiO2 led to better results than the use of WO3.

Component 3 project analyzed the testing of the wind microturbine electric generator designed to be integrated in the "smart grid" system of the Experimentarium module. Thus, for this application, analyzes were performed for the use of an electromagnetic excitation synchronous generator coupled to a vertical axis turbine that operates at speeds between 60-200 rpm, by using a speed multiplier with an amplification ratio of 1/10 allowing the generator to operate in a higher speed range up to 2000 rpm. The tests were performed in a stand that drives the variable speed generator. Another activity of the project focused on the implementation and testing of the electricity distribution network by integrating the DC network interface converter (24V/350V) from the micro-grid network, respectively the implementation of the power distribution network in dc using two direct current networks: a high voltage network (350V dc) and a low voltage network (24 V dc) that converts solar energy into electricity through a converter, i.e. energy storage in batteries. The system is based on a direct current energy distribution network, respectively on the monitoring and control of the electricity flow through a SCADA system, based on the decentralized “smart grid” system. In parallel, 53 temperature sensors, 14 humidity sensors and 3 CO2 sensors were installed to monitor the climatic characteristics of the facades. The remote data acquisition system is based on a measuring station, composed of 12 intelligent relays and the SCADA interface.

Component 4 project activities were focused on three main directions:

- Implementation of materials that allow absorption and degradation of air pollutants. This research was based on the comparison of numerical and experimental results for glass solar collectors and perforations of 50x50 mm. The study was based on a comparative numerical analysis performed on the two configurations of solar collectors with glass, with the distance between the glass and the absorbent plate of 30mm and 50mm respectively. The optimal result for the convective and solar collector efficiency was obtained for the 30mm absorbent plate configuration. Also, an air flow of 150 m3/h m2 is considered optimal for the glazed solar collector with perforated plate with holes of 50x50mm and distance of 30mm between the glass and the absorbent plate;

- Data monitoring for interior comfort optimization for the Experimentarium module. The aim of this research was to monitor the internal conditions of the Experimentarium module using the temperature, humidity and CO2 sensors. The obtained data between August and November 2020 allow the partial interpretation of the conditions for interior and exterior comfort, and the influences of the external and internal factors. Although the activity is ongoing, conclusions can be drawn about the behavior of the facades and the heat transfer through the walls of the facades.

- Environmental impact analyzes. Using a dedicated software (Gabi) and life cycle models, parallel environmental impact assessments LCA (Life-Cycle Assessment) were performed on different facade systems and prefabricated foundations, similar to those used in the EXPERIMENTARIUM module. For the realization of the models, both construction and End of the Life Cycle phases were considered, based on some disposal scenarios. In the façade systems case, the analyzes results show that all façade systems have similar scores, both for the production stage and for the end-of-life stage. However, there are some differences for the production phase, due to the possibility of reusing and recovering energy in the case of certain components of the facade systems. In the case of prefabricated foundations, the analyzes show that although in the production phase the impact of the prefabricated foundation is clearly higher than the in-situ cast foundation, high impact values are recovered at the end of the life cycle by reusing the prefabricated foundation.

Articles in WOS indexed journals

Articles in BDI indexed journals

Articles published in international and national conferences

During the international conference EENVIRO2020 (https://www.eenviro.ro/wp-content/uploads/2020/11/Program-EENVIRO-2020-v10.pdf), with the theme “Sustainable Solutions for Energy and Environment”, in 21 – 23 October 2020, in Bucharest, a special session (workshop) dedicated to the project was organized entitled Environment / CIA_CLIM Project, during which 6 research papers were presented.

During this stage, the application for a Utility Model entitled “Installation for remote monitoring of corrosion of zinc-coated and non-coated metal constructions embedded in soil” was sent to the State Office for Inventions and Trademarks (OSIM), on 22.07.2020.

Stage 3

Summary

List of paper