An experimental study of PV/T system using parabolic reflectors and heat exchanger

<p>Photovoltaic (PV) systems can be made more efficient by forcing the PV panel to operate at its maximum point power due to the electrical properties of photovoltaic generators, which are substantially non-linear (MPP). This study examines the effectiveness of using a combination of parabolic concentrator Bi-reflector and heat exchanger as a cooling system on the performance of photovoltaic generators to get a photovoltaic/thermal (PV/T) system, and their effect on the direct current (DCDC) converter using matrix laboratory (MATLAB) simulink. The experimental tests were carried out under various temperature values and sun irradiation. The results demonstrated that the use of parabolic Bi-reflectors, to further illumine te the panels, and the use of the cooling system to absorb excess heat to get heat water, could increase and enhances performances of the photovoltaic generator.</p>

Survey on Mitigating the Problems of Parabolic Reflectors for Efficient Communication

In this paper, various problems associated with parabolic reflectors, its causes and the approach to mitigate these problems are discussed. The problems include; side lobe radiations, edge diffraction, aperture blockage, cross polarisation, feed spill over, feed illumination taper, pointing error, surface error and phase error. These problems have adverse effect on the overall gain, efficiency and directivity of the antenna thereby inhibiting efficient communication process. The result of the survey reveals that, phase error tends to be the most difficult of the aforementioned problems due to the challenges associated with locating the phase centre at reflector’s focus. The aperture blockage seems to have the least method of solution, because the problem can be solved by changing the centre feed to an offset feed. Detailed investigation of these problems and the relevant solutions are necessary, since parabolic reflectors are among the most common antennas with diverse application.

Mechanical Sound Flux Amplifier for Diagnostics by the Auscultation Methods

The article notes that occupational safety in industry largely depends on the working equipment reliability. Among the various methods of maintaining equipment operability, there is a diagnostic method that helps to identify hidden defects before they appear. Thanks to equipment diagnostics, it is possible to increase safety, avoid accidents, catastrophes, and minimize repair and operation costs. There are two types of diagnostic methods: contact and non-contact. The most efficient non-contact methods are acoustic methods that are not associated with the destruction of the equipment under study. The possibility of applying the methods of auscultation used in medicine for diagnosing the state of industrial equipment is shown. Various methods and devices of auscultation are considered. The advantages and disadvantages of currently existing auscultation devices are noted. The design of an auscultation device with a mechanical sound flux seal is presented. Mechanical sealing of the sound flux is based on the parabolic reflectors use. The efficiency of using parabolic reflective surfaces is shown. A relationship is obtained that relates the magnitude of the amplification of the sound flux with the dimensions of the auscultation device. The results of calculations of the increase in the sound level in the auscultation device show that even with a sufficiently small ratio of the diameter of the inlet for the sound flux to the diameter of the outlet cross section of the sound flux and the diameter of the reduced parabolic reflector, a noticeable increase in the sound level is obtained when using a mechanical amplifier of the sound flux in the auscultation device.

Effect of Boosting Solar Radiation Intensity on Thermal and Hydraulic Performance and Characteristics of Forced Circulation Food Dryer Provided with Roughened Solar Air Heater

This paper focus on effects of boosting solar intensity on the thermal performance of solar food dryer coupled with roughened solar heater. Boosting of solar intensity increases the temperature of air entering into the food dryer without changing the specific humidity. The methods which have been used to increase the intensity of incidence radiation on the collector of food dryer are plane mirrors with tracking, parabolic reflectors and compound parabolic concentrator. It has been observed experimentally that boosting intensity improves performance characteristics of solar air heater and food dryer. It increases collector efficiency, dryer efficiency, loss of moisture content and diminishes the moisture content in the product at any time.