The paper presents the achievements of INCDIE ICPE-CA on wind installations provided with counter-rotating turbines. There are envisaged both the development of an experimental model and the results following the testing activities, respectively. The experimental model submits a novelty technological character due to the unconventional innovative aspects. It represents a foregoing constructive version, preceding a wind turbine prototype with the rated power of 10-15kW designed for power autonomy assurance within specific applications.The preliminary calculations, the numerical modelling of the wind rotors and the electric generator stand experiments have confirmed the energy conversion capacity for the double effect micro aggregate equal to 1kW for a 10 m/s wind velocity

The use of smart technologies and the Internet of Things (IoT) is becoming more and more popular in order to enhance the overall building performance by monitoring parameters related to occupants’ comfort and health in the built environment. A new modular, custom-made and replicable IoT system is proposed based on an Arduino development board (MKR WiFi 1010) connected to the Arduino IoT Cloud. An Application Programming Interface (API) enables the integration of this system with other possible ones, thus making the system modular, custom-made and replicable. A series of parameters were simultaneously monitored over a 7-day period in two office spaces and a photovoltaic (PV)-testing laboratory. While the meteorological and comfort parameters (temperature, relative humidity, CO₂) were monitored in all three spaces, the health parameters (total volatile organic compounds—TVOCs; formaldehyde—HCHO; particulate matter—PM; and radon—²²²Rn) were monitored only in an office setup located right next to a Chemical Analysis and Testing Laboratory. Generally, the registered values of the health parameters fell within the recommended thresholds. However, the thermal comfort parameters were constantly exceeded: over 90% of the working time in the two office spaces and 83.33% in the PV-testing laboratory. Still, the optimal relative humidity values in the monitored spaces contributed to the discomfort reduction in the occupants. Also, CO₂ and TVOCs had some exceptions in particular conditions. CO₂ values of up to 1500 ppm due to poor ventilation and TVOC levels of up to 1000 ppb related to chemical experiment development were registered. Also, several other peaks were recorded when monitoring HCHO as well as PM. Thus, special attention must be paid to natural ventilation or to the improvement of building characteristics. Also, the time intervals when experiments in the Chemical Analysis and Testing Laboratory are carried out should be communicated to other personnel from the nearest offices. The testing of the monitoring system over a one-week period showed that the proposed solution operated adequately, representing a reliable tool for data acquisition via the Arduino IoT Cloud.

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area.

In this paper we propose a new design of havesting system based on photovoltaic cells with antireflexive ZnO nanoparticles coatings and DC/DC isolation conversion. The system is based on an assembly of four photovoltaic polycrystalline cells provided with antireflexive ZnO nanoparticles coatings. The solar cells have been tested in terms of efficiency and output power for irradiance values in the range of 100 W/m² — 1000 W/m². The system of photovoltaic cells generates and transfers the energy to a DC/DC converter with galvanic separation. The converter uses a micro transformer with planar coils, ferrite magnetic circuit and magnetic colloidal nanofluid. The proposed model of micro transformer has been tested independently for frequencies of 100 kHz, 300 kHz and 500 kHz (which stands as the commutation frequency of the DC/DC converter), showing an efficient operation. The inductivity measurement proves that the inductivity of the primary winding is similar to the optimum inductivity of the DC/DC converter indicated by Texas Instruments manufacturing company which uses the LM 25017 integrated electronic circuit.