scholarly journals Efficiency of liquid flat-plate solar energy collector with solar tracking system

2015 ◽  
Vol 19 (5) ◽  
pp. 1673-1684 ◽  
Author(s):  
Marija Chekerovska ◽  
Risto Filkoski
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Tracking System ◽  
Radiation Heat Transfer ◽  
Solar Collectors ◽  
Cfd Modelling ◽  
Energy Capture ◽  
Operating Modes ◽  
Rotation System ◽  
Set Up

An extensive testing programme is performed on a solar collector experimental set-up, installed on a location in Shtip (Republic of Macedonia), latitude 41? 45? and longitude 22? 12?, in order to investigate the effect of the sun tracking system implementation on the collector efficiency. The set-up consists of two flat plate solar collectors, one with a fixed surface tilted at 30? towards the South, and the other one equipped with dual-axis rotation system. The study includes development of a 3-D mathematical model of the collectors system and a numerical simulation programme, based on the computational fluid dynamics (CFD) approach. The main aim of the mathematical modelling is to provide information on conduction, convection and radiation heat transfer, so as to simulate the heat transfer performances and the energy capture capabilities of the fixed and moving collectors in various operating modes. The feasibility of the proposed method was confirmed by experimental verification, showing significant increase of the daily energy capture by the moving collector, compared to the immobile collector unit. The comparative analysis demonstrates a good agreement between the experimental and numerically predicted results at different running conditions, which is a proof that the presented CFD modelling approach can be used for further investigations of different solar collectors configurations and flow schemes.

Experimental and numerical investigations on a high-density polyethylene (HDPE) blown film cooling with a new design of the counter-flow/radial jet air-ring

2021 ◽  
pp. 875608792110260
Author(s):  
ME Ismail ◽  
MM Awad ◽  
AM Hamed ◽  
MY Abdelaal ◽  
EB Zeidan
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Film Cooling ◽  
Radiation Heat Transfer ◽  
Absolute Error ◽  
Numerical Results ◽  
Upper Lip ◽  
Original Design ◽  
Blown Film ◽  
Set Up

This study experimentally and numerically investigates a typical HDPE blown film production process cooled via a single-lip air-ring. The processing observations are considered for the proposed subsequent modifications on the air-ring design and the location relative to the die to generate a radial jet, directly impinging on the bubble. Measurements are performed to collect the actual operating parameters to set up the numerical simulations. The radiation heat transfer and the polymer phase change are considered in the numerical simulations. The velocity profile at the air-ring upper-lip is measured via a five-hole Pitot tube to compare with the numerical results. The comparison between the measurements and the numerical results showed that the simulations with the STD [Formula: see text] turbulence model are more accurate with a minimum relative absolute error (RAE) of 1.6%. The numerical results indicate that the peak Heat Transfer Coefficient (HTC) at the impingement point for the modified design with radial jet and longer upper-lip is 29.1% higher than the original design at the same conditions. Besides, increasing the air-ring upper-lip height increased the averaged HTC, which is 13.4% higher than the original design.

scholarly journals Use of CFD Modelling for Transpired Solar Collectors and Associated Characterization of Multi-scale Airflow and Heat Transfer Mechanisms

2015 ◽  
Vol 78 ◽  
pp. 2238-2243 ◽  
Author(s):  
Sadjad Tajdaran ◽  
Fabrizio Bonatesta ◽  
Raymond Ogden ◽  
Christopher Kendrick
Keyword(s):  
Heat Transfer ◽  
Solar Collectors ◽  
Cfd Modelling ◽  
Multi Scale ◽  
Transfer Mechanisms

Design and Analysis of Solar Tracking System for Multipurpose Domestic Applications

2013 ◽  
Author(s):  
P. Rhushi Prasad ◽  
P. B. Gangavati ◽  
H. V. Byregowda ◽  
K. S. Badarinarayan
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Flat Plate ◽  
Tracking System ◽  
Solar Collectors ◽  
Tracking Systems ◽  
Pv Panel ◽  
Energy Conversion Systems ◽  
Flat Plate Collector ◽  
Parabolic Collector

Now-a-days the field of applied mechanical systems opens new horizons for the use of orientation mechanisms. The opportunity to use mechanisms with a “sustainable purpose” leads to new approaches in the development of renewable energy systems design. The evaluation of the existing products shows that the tracking mechanisms for solar energy conversion systems may improve the efficiency of the solar energy conversion systems up to 30% to 50%. Applications of solar energy for domestic and industrial heating purposes have been becoming very popular. However the effectiveness of presently used fixed flat plate collectors, PV panels and parabolic collector are low due to the moving nature of the energy source. The presents research was carried out in the field of increasing the efficiency of the solar energy received by the solar collectors like PV panels, Flat plate collectors, Cylindrical Parabolic collectors using tracking systems by changing the position of the solar collectors correlated to the sun position for getting maximum radiation use of beam radiation falling on the solar collector. Two main aspects are taken into consideration, one optimizing the interaction between the mechatronic system components by integrating the analog electronic system by using a 555 timer in the mechanical model, and secondly by reducing the cost & time for the design process. The research work was carried out for location in chickballapur district at BGS R&D centre in Karnataka State, India. The results obtained in work is 24% increase in tracking efficiency of experimental model of flat plate collector, 30% increase in tracking efficiency in working model flat plate collector, 39 % increase in tracking efficiency of cylindrical parabolic collector and 36% increases in tracking efficiency of the Photovoltaic panel is found when compared to the non-tracking systems respectively. This paper presents the results of PV panel collector in detail for increasing the efficiency of the PV panel collector by tracking system with comparison of non-tracking system.

scholarly journals Feasibility Analysis and Performance Evaluation and Optimization of a DXSAHP Water Heater Based on the Thermal Capacity of the System: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3883
Author(s):  
Jorge E. De León-Ruiz ◽  
Ignacio Carvajal-Mariscal ◽  
Antonin Ponsich
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pump ◽  
Thermal Capacity ◽  
Hot Water ◽  
Outlet Temperature ◽  
Solar Collectors ◽  
Pump System ◽  
Heat Pump System

The present work conducts an evaluation of the feasibility and the overall performance and consequent optimization of a direct expansion solar assisted heat pump (DXSAHP) employed for domestic water heating. For the study conducted R134a, R404A, R407C and R410A working fluids were evaluated as well as the use of four, six and eight flat-plate solar collectors and a worktime ranging from 1 to 6 h. The case study is based in Mexico City with a 300 L container and a hot water outlet temperature of 51 °C. The paper introduces a new evaluation criterion based on the thermal capacity and all the evaluations conducted throughout this research revolve around this performance metric. The results show that, the system would require at least 4 h of operation to achieve the outlet temperature. Additionally, it was found that the R410A refrigerant has the best heat transfer properties; with an average condensation heat rate of 6.31 kW, followed by the R407C with 5.72 kW, the R404A with 5.42 kW and the R134a with 5.18 kW. Diversely, the R134a refrigerant requires 0.402 kW of compression work, 62% less than the R410A, which requires 1.06 kW. Consequently, R134a delivers the highest COP, which ranges from 7 to 14, followed by the R407C and R404A refrigerants, which present a similar behaviour between them, with COP ranging from 5 to 9 and 4 to 8, respectively, and finally the R410A, achieving the lowest COP, ranging from 3.5 to 6.5. Moreover, it was found that the R134a presents a higher dispersion regarding the energy exchange rate, which reveals that it is the fluid most susceptible to external factors, such as the weather. Contrarily, the remaining refrigerants present a more consistent performance. Finally, the optimization revealed that the R407C refrigerant is the most suitable given that it requires 20% less compression work than the R404A. This provides the heat pump system with a steadier behaviour, a COP ranging from 7 to 8, 30% higher than R410A, a worktime decrease of 1.5 h and heat transfer area of 5.5 flat-plate solar collectors, equivalent to a 31% reduction, both compared to R134a.

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