Thermal performance of a low and medium temperature flat plate solar collector when controlling the output-input temperature difference and the tilt angle

2021 ◽  
pp. 1-17
Author(s):  
García-Rincón Marco Antonio ◽  
Flores-Prieto José Jassón ◽  
Montoya-Márquez Orlando
Keyword(s):  
Flat Plate ◽  
Temperature Difference ◽  
Vertical Position ◽  
Solar Collectors ◽  
Medium Temperature ◽  
Joule Effect ◽  
Heat Flow Calorimetry ◽  
Flat Plate Solar Collector ◽  
Overall Heat Loss Coefficient ◽  
Indoor Conditions

Abstract This work presents a sensitivity analysis of the overall heat loss coefficient UL and the thermal efficiency η in low and medium temperature encapsulated flat plate solar collectors when controlling the output-input temperature difference ΔT and the angle of inclination β. The UL and η were determined using heat flow calorimetry at indoor conditions, emulating the solar radiation by the Joule effect and a PID control. The angle of inclination β range was 0-90°, and the ΔT range was 5.0-25.0 K. The ambient temperature and the mass flow rate were preset for each test. The UL experimental uncertainty was ±0.85 W/m2K for the inclination range of 0-45° and ±0.27 W/m2K for the inclination range of 45-90°. The results matched previous outcomes with a difference of up to 0.3 W/m2K. The UL behaved exponentially as β increased from horizontal to vertical position and linearly with ΔT. It was also observed that the UL and the efficiency were sensitive to the confined airflow variations. This model shows a sensitivity of low and medium temperature flat plate solar collectors, as the efficiency increased 140% when β was raised and 40% with ΔT.

scholarly journals Aplicaciones del Captador Solar de Placa Plana y del Captador de Tubo de Vacío en la Edificación = Applications of the Flat Plate Solar Collectors and the Vacuum Tube Solar Collectors in Building

2018 ◽  
Vol 4 (3) ◽  
pp. 25 ◽  
Author(s):  
Daniel Ferrández ◽  
Carlos Moron ◽  
Jorge Pablo Díaz ◽  
Pablo Saiz
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Energy Demand ◽  
Hot Water ◽  
Solar Thermal ◽  
Solar Collectors ◽  
Thermal Systems ◽  
Vacuum Tube ◽  
Solar Thermal Collectors ◽  
Flat Plate Solar Collector

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.

Investigating the Effect of Al2O3/Water Nanofluid on the Efficiency of a Thermosyphon Flat-Plate Solar Collector

2016 ◽  
Author(s):  
Mohamed Nabeel A. Negm ◽  
Ahmed A. Abdel-Rehim ◽  
Ahmed A. A. Attia
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Fossil Fuels ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Green Energy ◽  
Working Fluid ◽  
Steady Increase ◽  
Solar Collectors ◽  
Flat Plate Solar Collector

The world is still dependent on fossil fuels as a continuous and stable energy source, but rising concerns for depletion of these fuels and the steady increase in demand for clean “green” energy have led to the rapid growth of the renewable energy field. As one of the most available energy sources with high energy conversion efficiency, solar energy is the most prominent of these energies as it also has the least effect on the environment. Flat plate collectors are the most common solar collectors, while their efficiency is limited by their absorber’s effectiveness in energy absorption and the transfer of this energy to the working fluid. The efficiency of flat plate solar collectors can be increased by using nanofluids as the working fluid. Nanofluids are a relatively recent development which can greatly enhance the thermophysical properties of working fluids. In the present study, the effect of using Al2O3/Water nanofluid as the working fluid on the efficiency of a thermosyphon flat-plate solar collector was experimentally investigated. The results of this experiment show an increase in efficiency when using nanofluids as the working fluid compared to distilled water. It was found that Al2O3/water nanofluids are a viable enhancement for the efficiency of flat-plate solar collectors.

scholarly journals Experimental comparative analysis of operating characteristics of double circuit flat-plate solar collector with thermosiphon circulation and flat solar collector with chemical coating

2021 ◽  
pp. 173-173
Author(s):  
Yedilkhan Amirgaliyev ◽  
Murat Kunelbayev ◽  
Talgat Ormanov ◽  
Talgat Sundetov ◽  
Salauat Daulbayev
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Heat Supply System ◽  
Heat Output ◽  
Solar Collectors ◽  
Operating Characteristics ◽  
Chemical Coating ◽  
Operation Process ◽  
Executive System ◽  
Flat Plate Solar Collector

The given article considers results of experimental measurements, productivity comparison and master controller executive system of flat-plate solar collector with thermosiphon circulation and flat solar collector with special chemical coating. There has been developed master controllers control module, which receives data from temperature and lighting sensors, obtained in operation process. The aim of the research is getting the solar collectors? optimal parameters, representing maximal usage performance index, controllability, as well as, construction type, allowing energy saving. In the recent years flat-plate solar collectors with chemical coating are characterized with higher efficiency in real conditions usage. The developed master controllers? executive system is used for monitoring the installation?s main parameters, as well, it permits to compare characteristics of solar collector with thermosiphon circulation to those of flat-plate solar collector with chemical coating. The obtained experimental data has shown, that flat solar collectors, using chemical coating as a transfer medium in solar heat supply system, have an advantage in the context of usage effectiveness. The heat output and water heating in a flat solar collector are calculated, which vary depending on the intensity of solar radiation. The thermal efficiency of a flat solar collector with a thermosiphon tank based on the Mojo V3 platform using Dallas sensors is calculated.

Performance of the Flat Plate Solar Collector Operated with Water-Al2O3 Nanofluid

2016 ◽  
Vol 831 ◽  
pp. 181-187 ◽  
Author(s):  
Janusz T. Cieśliński ◽  
Bartosz Dawidowicz ◽  
Aleksandra Popakul
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Base Fluid ◽  
Fossil Fuels ◽  
Thermal Characteristics ◽  
Working Fluid ◽  
Solar Collectors ◽  
Recent Method ◽  
Flat Plate Solar Collector

Solar collectors is one of the technologies absorbing energy from solar beam and utilizing it for heating purposes, displacing the need to burn fossil fuels. There are many ways to improve effectiveness of the solar collectors [1,2]. Recent method to absorb more heat from the solar beam is to modify thermal characteristics of the working fluid. For this purpose one can use nanofluids, i.e. suspensions of metallic or nonmetallic nanoparticles in a base fluid [3].

scholarly journals Improving the Thermal Efficiency of Flat Plate Solar Collector Using Nano-Fluids as a Working Fluids: A Review

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Saif Ali Kadhim ◽  
Osama Abd AL-Munaf Ibrahim
Keyword(s):  
Flat Plate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Base Fluid ◽  
Working Fluid ◽  
Solar Collectors ◽  
Nano Fluid ◽  
Flat Plate Solar Collector ◽  
Nano Fluids ◽  
Better Than

Solar energy is one of the most important types of renewable energy and is characterized by its availability, especially in Iraq. It can be used in many applications, including supply thermal energy by solar collectors. Improving the thermal efficiency of solar collector leads to an increase in the thermal energy supplied. Using a nano-fluid instead of base fluid (water is often used) as a working fluid is a method many used to increase the thermal efficiency of solar collectors. In this article, the latest research that used nano-fluid as a working fluid in evaluating the thermal efficiency of solar collector, type flat plate was reviewed. The thermal efficiency improvement of flat plate solar collector was reviewed based on the type of nanoparticles (metal oxides, semiconductors oxides, carbon compounds) used in the base fluid and comparison was made between these nanoparticles under the same conditions. Moreover, the effect of varying the concentration of nanoparticles in the base fluid and changing the working fluid flow rate on the thermal efficiency of flat plate solar collector was also reviewed. The results of the review showed that nano-fluids containing carbon compounds are better than other nano-fluids and that copper oxide is better than the rest of the metal oxides used in improving the thermal efficiency of flat plate solar collectors.

Experimental and numerical analysis of an efficiently optimized evacuated flat plate solar collector under medium temperature

2020 ◽  
Vol 269 ◽  
pp. 115129 ◽  
Author(s):  
Datong Gao ◽  
Guangtao Gao ◽  
Jingyu Cao ◽  
Shuai Zhong ◽  
Xiao Ren ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Flat Plate ◽  
Solar Collector ◽  
Medium Temperature ◽  
Flat Plate Solar Collector

Gas radiative effects on gas-filled flat plate solar collectors

2019 ◽  
Vol 97 (10) ◽  
pp. 1115-1124 ◽  
Author(s):  
Khosro Lari ◽  
Ali Tarokh ◽  
Mohammad Naghizadeh
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Air Temperature ◽  
Solar Collector ◽  
Hot Water ◽  
Discrete Ordinates ◽  
Solar Collectors ◽  
Radiative Effects ◽  
Wide Range ◽  
Flat Plate Solar Collector

A standard thermal solar collector can be used for both hot water production and air heating purposes. Gas-filled solar collectors represent a new emerging design approach with enhanced characteristics. In this research, numerical modeling is utilized to study radiative effects of the participating gases on the performance of solar collectors. The coupled radiative–convective heat transfer in the solar collector is considered and the collector cavity is considered as a radiatively participating medium. The finite volume method has been adopted to solve the governing equations and discrete ordinates method is used for radiative transfer. After validating the model used in this study, it is used to obtain the heat transfer characteristics of a flat-plate solar collector with real solar conditions of the city of Kerman, Iran, in summer at a wide range of air absorption coefficients. According to the results, by increasing the absorption coefficient of the air, the temperature of the absorber plate is reduced and the air temperature is increased, but the increase of air temperature is much higher than the reduction of absorber temperature. Hence, it is concluded that it is possible to use participating gases in the solar air heaters to enhance the performance of the collector.

Experimental Performance Analysis of External Compound Parabolic Concentrators With Low Concentration Ratios for Medium Temperature Applications

2014 ◽  
Author(s):  
Donghao Xu ◽  
Ming Qu
Keyword(s):  
Experimental Data ◽  
Flat Plate ◽  
Operating Temperature ◽  
Industrial Process ◽  
Solar Collectors ◽  
Medium Temperature ◽  
Actual Performance ◽  
Low Concentration ◽  
Solar Tracking ◽  
Operating Temperatures

Due to the mounting concerns about climate changes and depletion of fossil fuels, solar energy, as one type of renewable energy, has attracted a lot of interests from academia, industries, and government in the past few decades. Currently, solar thermal technologies have been applied to the applications at the low operating temperature below 100°C by using flat-plate solar collectors and at the high operating temperature above 250°C by using solar tracking concentrators. For the medium operating temperatures between 100°C and 250°C, flat-plate solar collectors can hardly reach 100°C and solar tracking concentrators are too expensive. In this context, the use of external compound parabolic concentrators (XCPC) for applications operated at medium temperature draws quite attentions because of its higher efficiency than flat plate solar collectors and better cost effectiveness than solar tracking concentrators. However, currently only a few experimental data is available on the actual performance of XCPCs from literatures, especially for the recently new XCPCs with a low concentration ratio. In order to contribute to the knowledge, a series of experiments have been conducted on the new XCPCs recently installed at Bowen Lab, Purdue University, West Lafayette, Indiana. The experiments showed that the XCPCs raised the temperature to 170°C, which is 140°C higher than the ambient temperatures, with a thermal efficiency of 29%. Based on the data collected from the experiments, the optical and thermal efficiencies of XCPCs are determined for different solar irradiations, operating temperatures, and incident angles. A new regression model is proposed and fitted accordingly. The experimental data and analysis demonstrated the feasibility and potentials of using XCPCs for applications in medium temperature range such as solar absorption cooling and heating systems, seawater desalination, solar disinfection, post-combustion carbon capture systems and other industrial process heating.

scholarly journals Heat Removal Factor in Flat Plate Solar Collectors: Indoor Test Method

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2783
Author(s):  
Orlando Montoya-Márquez ◽  
José Flores-Prieto
Keyword(s):  
Flat Plate ◽  
Tilt Angle ◽  
Heat Removal ◽  
Test Method ◽  
Electrical Heating ◽  
Inlet Temperature ◽  
Solar Collectors ◽  
Linear Behavior ◽  
Useful Heat ◽  
Overall Heat Loss Coefficient

This paper presents a couple of methods to evaluate the heat removal factor FR of flat plate solar collectors, as well as a parametric study of the FR against the tilt angle β, and (Ti − Ta)/G, and its effects on the a0-factor (FRτα) and the a1-factor (FRULmin). The proposed methods were based on indoor flow calorimetry. The first method considers the ratio of the actual useful heat to the maximum useful heat. The second takes into account the slopes of the family of efficiency curves (FRULmin) according to ANSI/ASHRAE 93-2010, and the minimum overall heat loss coefficient, ULmin. In both methods, a feedback temperature control at collector inclinations from horizontal to vertical allows the inlet temperature and the emulating of the solar radiation to be established by electrical heating. The performance of the methods was determined in terms of the uncertainty of the FR. Method 1 allowed a three-fold improved precision compared to Method 2; however, this implied a more detailed experimental setup. According to the first method, the effects of the tilt angle β, and the (Ti − Ta)/G, on the a0-factor were considerable, since FR is directly proportional to the a0-factor. The changes in (Ti − Ta)/G caused an average change in FR of 32% The FR shows almost linear behavior for inclinations from horizontal to vertical with a 14.5% change. The effects of β on the a1-factor were not considerable, due to the compensation between the increase in FR and the decrease in ULmin as β increased.

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