Experimental Evaluation of Thermals Performances of The Solar Dryer with Parabolic Trough Collector

A cylindrical-parabolic solar-thermal converter, with 0.5m2 of capture surface, was manufactured and attached to a furnace, constituting an indirect solar dryer. Thermal balances of the elements of the receiver, housed in the focal point of this collector, are settled. A campaign of vacuum tests of this dryer indicated temperatures of the heat-bearing air in natural convection, along the absorber tube (70°C) and inside the drying cage (almost 60°C,on average). The average thermal efficiency of said converter has been evaluated at 50%.The higher the efficiency, the less the converter's capture surface is required and, therefore, less investment is required. These promising results testify to the effective performance of this new dryer compared to dryers with flat collectors, whose efficiencies could not exceed 40% despite the large surface area of these collectors.

PCM-Based for Heat Storage in Solar-Thermal Converter

Solar thermal energy is one of the promising renewable and sustainable energy that have gain research interest. However, the nature of intermittent solar irradiation limits the usage of this energy. Phase change material (PCM) are substance that has the property of absorbing and releasing thermal energy through phase transformation. Combination of graphene foam/PCM composite will be able to absorb heat from solar thermal energy and sustain energy release to thermoelectric generator (TEG) for electrical conversion. Two different PCM material were tested which are petroleum-based paraffin wax and bio-based PCM beeswax. Thermal properties of both materials were measured using DSC and heat absorption were tested under real solar irradiation. This solar-thermal converter showed that graphene/paraffin/beeswax composite is more effective than the paraffin wax or beeswax alone. The recorded results also showed that combination of these petroleum based and bio-based PCM with added graphene foam could retain longer heat than graphene/paraffin wax and individual PCM. The longer heat can be stored in solar-thermal converter device may sustain electricity generation even with absence of solar energy.

Interlaboratory Comparison of Thermal AC Voltage Standards

The article presents results of comparison of the thermal converter of nominal input voltages equal to 10 V from the set of Polish National AC voltage standards, maintained at the Central Office of Measures in Warsaw, with the primary AC voltage 5 V standard, developed and maintained at the AC-DC Transfer Laboratory of the Department of Measurement Science, Electronics and Control at the Faculty of Electrical Engineering of the Silesian University of Technology in Gliwice.

An Application of the ECMS Strategy to a Wankel Hybrid Electric UAV

In a previous work, the authors optimized the hybrid electric power system for a tactical Unmanned Aerial Vehicle including a Wankel engine as thermal converter and a permanent magnet electric motor powered by lithium batteries. Startingfrom this optimal configuration, we address here the topic of a refined optimization of the energy management strategy, i.e. the contribution of the battery to the required power in each segment of the flight. The Equivalent Consumption Minimization Strategy (ECMS) was chosen with the goal of minimizing fuel consumption while fully depleting the energy stored in the battery from the beginning to the end of each mission.

Improving the efficiency of the heat and power system, due to the synthesis of control based on the synergistic concept

The article describes a special case of the synthesis of the electromechanical system for controlling the thermal regime by the method of analytical design of aggregated regulators. The task was to base the synthesis of the optimal in speed electromechanical system for stabilizing the operating modes of the thermodynamic system, based on the use of the Peltier module as a thermal converter.