Flat Solar Collector Research Articles

Experimental Evaluation of an Innovative Non-Metallic Flat Plate Solar Collector

The present article deals with the concept of the non-metallic flat plate liquid solar collector and its evaluation. The innovative concept lies in the elimination of metal parts of the solar collector and their replacement by the foam glass block, which significantly reduces the energy and material demands of the production process. The evaluation of the collector took place in two phases, the first was focused on the numerical evaluation, which resulted in the compilation of a theoretical curve of the efficiency of the solar collector. The second phase was focused on verifying the basic functionality of the concept based on the results obtained from experimental tests of the collector, which confirmed the functionality of the concept and revealed several areas that will need to be addressed in the further development of the prototype.

A fast dissipative robust nonlinear model predictive control procedure via quasi‐linear parameter varying embedding and parameter extrapolation

AbstractIn this article, a robust model predictive control (MPC) procedure for quasi‐linear parameter varying (qLPV) systems is proposed. The novelty resides in considering a recursive extrapolation algorithm to estimate the values of the scheduling parameters along the prediction horizon , which fastens the sluggish performances achieved with the robust qLPV MPCs from the literature. The bounds on the estimation errors of the scheduling parameters through are taken into account by the robust MPC, which solves an online min‐max problem: first, a constrained convex program is resolved in order to determine the worst‐case bound on the cost function and, subsequently, a second constrained quadratic program is solved to minimize this worst‐case cost function with respect to a control sequence vector. Since the bounds on the estimation error for the scheduling parameters are usually much smaller than the bounds on the actual scheduling parameter, the conservativeness of the solution is quite reduced. Recursive feasibility and stability of the proposed algorithm are demonstrated with dissipativity arguments given in the form of a linear matrix inequality remedy, which determines the zone of attraction for which input‐to‐state stability is ensured. The nonlinear temperature regulation problem of a flat solar collector is considered as a case study. Using a realistic simulation benchmark, the proposed technique is compared to other robust min‐max LPV MPC algorithms from the literature, proving itself efficient while achieving good performances.

Three-Dimensional Numerical Simulation of a Flat Plate Solar Collector with Double Paths

Flat air solar collectors are used for heat transfer between the absorber and the heat transfer fluid, to improve this transfer there are several methods. Among these methods, the exchange surface lengthening and the creation of turbulence. In this work is done to give a comparison between two types of solar collectors, so we have made an improvement of Ben Slama Romdhane's solar collector by creating two air flow passages to increase heat transfer. We made a 3D simulation of a flat air solar collector with transverse baffles which causes turbulence and increases the exchange surface; we use the ANSYS calculation code to make the simulation and gives results with a brief time and minimal cost.

Experimental Studies of the Influence of Microencapsulated Phase Change Material on Thermal Parameters of a Flat Liquid Solar Collector

The article presents the results of preliminary research aimed at determining the possibility of using microencapsulated phase change material (mPCM) slurries as a working fluid in installations with a flat liquid solar collector. In the tests, the following were used as the working fluid: water (reference liquid) and 10% wt. and 20% wt. of an aqueous solution of the product under the trade name MICRONAL® 5428 X. As the product contained 43% mPCM, the mass fraction of mPCM in the working liquid was 4.3% and 8.6%, respectively. The research was carried out in laboratory conditions in the range of irradiance I = 250–950 W/m2. Each of the three working fluids flowed through the collector in the amount of 20 kg/h, 40 kg/h, and 80 kg/h. The working fluid was supplied to the collector with a constant temperature Tin = 20 ± 0.5 °C. It was found that the temperature of the working fluid at the collector outlet increases with the increase in the radiation intensity, but the temperature achieved depended on the type of working fluid. The greater the share of mPCM in the working liquid, the lower the temperature of the liquid leaving the solar collector. It was found that the type of working fluid does not influence the achieved thermal power of the collector. The negative influence of mPCM on the operation of the solar collector was not noticed; the positive aspect of using mPCM in the solar installation should be emphasized—the reduced temperature of the medium allows the reduction in heat losses to the environment from the installation, especially in a low-temperature environment.

Research of Heat Losses of Solar Collectors and Heat Accumulators

The article discusses the features of heat losses by convection and radiation of flat solar collectors on the basis of a non-stationary thermal model and program. The connection of heat losses with the generalized heat loss coefficient of solar collectors is shown. The article also deals with the problem of determining the distribution of temperatures and heat losses by convection and radiation of a thermal insulation system – accumulating body (water) for a spherical heat accumulator under symmetric boundary conditions. The problem is solved numerically according to the program developed on the basis of the proposed “gap method.” The method and program for the numerical calculation of heat losses and temperatures in time in a spherical two-layer heat accumulator with symmetric boundary conditions, taking into account both incident and intrinsic radiation, have been developed. The program has been developed for a “long” two-layer cylindrical heat accumulator of solar collectors.

Визначення кількості сонячної енергії, що сприймається сферичним трубчастим колектором

Spherical solar tubular collector (SSTK) was invented in A. Pidgorny IPMash. as an alternative to the solar flat collector to convert the radiant energy of the Sun into heat. To understand the efficiency of a collector, it is important to know how much energy it can take. A methodology for calculating the amount of heat perceived by the collector has been developed. The surface area of a spherical tubular collector illuminated by the Sun using proposed methodology was determined. The amount of heat received by the solar collector for each day of the year was estimated. The total amount of heat received by SSTK in Kharkiv during the year was defined. Keywords: solar energy, spherical solar tubular collector, amount of heat

Optimization of Flat-Plate Solar Air Heater for Drying Mangifera Indica by Using Karush Kuhn Tucker (KKT) Conditions

The increase of the world demographic distribution makes the continuous and large-scale production of food necessary. Some of these are perishable fruits and vegetables, whose handling times between harvest and consumption should be short. In order to reduce the amount of food wasted in storage and distribution stages, the implementation of a dehydrator system is proposed. This kind of systems regulates the airflow and the air temperature in closed and controlled environments with the aim of extracting the food moisture in order to preserve it for longer periods. With the arrival of alternative energies and their multiple applications, this works presents the design and the development of a system for drying tropical fruits, specifically Mangifera Indica, using the sun as primary source of energy in flat solar collector in order to replace the electrical consumption of conventional drying equipment, offering an alternative in areas with limited access to the electricity network. In addition, optimization algorithms have been used to compute the mechanical design parameters, and six designs with manufacturing variations have been compared, obtaining as max outlet temperature a value of 66 °C.

Comparative analysis of a flat solar collector and flat solar collector with chemical coating

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 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.

A novel dual-diameter closed-loop pulsating heat pipe for a flat plate solar collector

The main idea of this investigation is to increase the thermal efficiency of a flat plate closed-loop pulsating heat pipe solar collector by introducing a novel closed-loop pulsating heat pipe (CLPHP) with a dual-diameter structure. The CLPHP with dual-diameter configuration is made of copper with two diameters; larger in the condensation section (inner diameter of 3.5 mm) and smaller in the evaporation and adiabatic sections (inner diameter of 2 mm). The thermal performance of this type of CLPHP was investigated at different filling ratios and inclination angles. Results showed that the thermal performance of the dual-diameter configuration is considerably better than the single-diameter in the vertical and non-vertical orientations. Moreover, in this study, the performance of a flat plate solar collector coupled with the proposed dual-diameter CLPHP (DD-CLPHPSC) is investigated experimentally in outdoor and indoor modes during July and August of 2020, under local weather conditions of Mashhad, Iran. The effects of the filling ratio, inclination angle, and solar intensity were assessed. Under sunny weather conditions, when the direct normal irradiance was 1030 W/m2, the thermal efficiency of the DD-CLPHPSC with a filling ratio of 60% reached 72.4%.

A Series Arrangement of Economizer – Evaporator Flat Solar Collectors as an Enhancement for Solar Steam Generator

A Series Arrangement of Economizer – Evaporator Flat Solar Collectors as an Enhancement for Solar Steam Generator

NUMERICAL ANALYSIS OF AN INTEGRATED SOLAR COOLING AND HEATING SYSTEM IN INDIVIDUAL HOUSE IN DIFFERENT ALGERIAN CLIMATES

There is a growing concern about energy use in Algeria. With rapid building development programs and improvements of the living conditions, building sector is will continue to be a major energy end-user. Main energy needs in buildings are due to heating and/or cooling, depending on local climatic conditions and type of building. In this paper. The primary aim was to analyze in two aspects – heating load, and cooling load of individual house energy consumption in the major climatic zones in Algeria. The individual house used heating and cooling solar system. The system performance was simulated using TRNsys program. This solar heating and cooling system incorporates between 89 m2 and 170 m2 of flat plate double glazed solar collectors provide solar energy contribution during both the heating and the cooling seasons; between 13.28 kW and 25.11 KW single effect, water– lithium bromide (H2O/LiBr) absorption chiller, for space cooling and heating, this system is the smallest solar heating and cooling system in the world.

Synthesis, Optical Properties and Stabilization of ZnS Quantum Dots by Polymeric Matrices

ZnS QDs were synthesized by chemical co precipitation method and then embedded in polyvinyl alcohol (PVA) with different concentrations of ZnS. The samples of ZnS/PVA were characterized by X-ray diffraction (XRD), transmission electron microscopy and Scanning Electron Microscopy. The XRD study showed that the crystallite size was around 9 nm. UV/VIS optical spectroscopy studies were used to determine the energy band gap of ZnS/PVA nanoparticles films against the increase of concentration. The photo stability of QDs ZnS/PVA composites are highlighted. The photo stability rate was enhanced to 48% after 420 min for UV–VIS irradiation. The nanocomposite ZnS/PVA has the optimum properties as a proper candidate for flat panel display, LED and solar collector.

Numerical modeling of a flat air solar collector fitted with obstacles

The weakness of the solution of flat-air solar collectors in the absence of a turbulence promoter has led researchers to seek other means to improve the performance of the collector. to improve the heat exchange in the air stream from the flat solar collector to the air is the creation of baffles or obstacles to give the longest possible flow path and create a large possible turbulence network. In this article, we studied an air flow around an obstacle field in a flat air solar collector, using the Ansys CFX calculator software, we make a digital 3 D similarity and we give results on the heat exchange in the flat air solar collector and the aim of this study is to show the effect of the obstacles for the fluid flow and the heat transfer in the fluid flow of the flat air solar collector.

Modeling the Performance of a Flat Solar Collector Based on Cellular Polymeric Materials

Currently, in the field of energy supply of agro-industrial facilities, there is an increasing interest in the development of new structures and engineering systems using solar energy, including flat solar collectors based on cellular polymer materials. Modern solar collectors based on metal absorbers, despite their high efficiency, have a large specific weight, high metal consumption and cost. The use of cellular polymer materials for the manufacture of solar collector absorbers reduces the cost and reduces the weight of the installation. (Research purpose) The research purpose is in conducting a numerical simulation of the performance of a flat solar collector based on cellular polymer materials. (Materials and methods) Authors used analytical methods for mathematical modeling of a flat salt collector based on cellular polymer materials. The article presents a mathematical model of a flat solar collector in the computer program ANSYS Fluent. The distribution contours of temperature and pressure of the coolant in the channels of a flat solar collector were obtained at different values of the coolant flow rate at the inlet. (Results and discussion) The article presents comparison the temperature of the coolant at the output of the solar collector on the flow rate of the coolant obtained analytically and using the developed CFD model. The results of verification of the calculated model of the solar collector showed its adequacy and high convergence of the data obtained using the computer model. (Conclusions) The article presents a design of a flat solar collector based on cellular polymer materials. The developed design of a flat solar collector allows us to reduce the specific weight more than three times and reduce the cost while maintaining high thermal performance.

Experimental analysis of thermal performance for flat plate solar water collector in the climate conditions of Yekaterinburg, Russia

Abstract Current experimental work studies the thermal performance of a flat plate solar water collector according to the weather conditions of the city of Ekaterinburg in Russia. All tests were carried within four months and four typical clear days were chosen for each month. Thermal efficiency, useful energy, and water temperatures at the inlet and outlet of the flat plate solar collector have been investigated in this study. The results were collected during summer and autumn have been analyzed to find out the effect of different weather conditions on the performance of the proposed flat solar water collector. The highest efficiency of the solar collector was recorded during midday when the collector receives the highest solar energy intensity and thus the highest rate of useful heat gained. The maximum efficiency observed by 66% in July compared to the other months included in the current study. The results showed good agreement between the previous studies and the current proposed solar water collector in terms of thermal efficiency.

Evaluation of productivity enhancement of a solar still coupled with flat solar collector and parabolic trough under medina climate

Evaluation of productivity enhancement of a solar still coupled with flat solar collector and parabolic trough under medina climate

Rural house heat supply system based on solar energy

The article examines the solar energy-based heat supply system of individual rural houses as the object of research. Currently, the volume of construction of standard houses in rural areas of the Republic of Uzbekistan is growing, which in turn leads to the problem of saving traditional energy resources and uninterrupted heat supply in their heating system. The authors proposed a scheme of a combined heat supply system with a flat solar collector and a water heating boiler in order to save fuel energy resources in the heating system of rural houses. In the article, experiments and measurements were carried out on the basis of experimental calculation methods in a solar heating system installed in an experimental solar house. Based on the conducted experiments, the thermal-technical characteristics of the proposed system, the thermal efficiency of the collector and the temperature regime were analyzed. The results of the study show that the maximum heat output of the flat solar collector was 8.7 kW, and the temperature of the hot water at the entrance to the heating system was 45-50 0C. As a result of the application of the proposed combined heat supply system, 50% of the heat load in the daytime mode on sunny days was covered by solar energy.

Thermal-Technical characteristics and thermal regime of energy-efficient solar house

The article examines the solar energy-based heat supply system of individual rural houses as the object of research. Currently, the volume of construction of standard houses in rural areas of the Republic of Uzbekistan is growing, which in turn leads to the problem of saving traditional energy resources and uninterrupted heat supply in their heating system. The author proposed a scheme of a combined heat supply system with a flat solar collector and a water heating boiler in order to save fuel energy resources in the heat supply system of energy-efficient solar houses.

Estimation of Solar Hot Water System Operation for a Residential Building

Solar hot water supply systems can provide a significant part of the thermal energy needed in the residential sector. The use of solar hot water supply systems can reduce the consumption of traditional energy sources and, consequently, reduce greenhouse gas emissions. The aim of this article is to assess the operation of the solar heating system operation to provide the needs of the hot water supply system of a residential building with thermal energy. The efficiency of a flat solar collector operating in a single-circuit thermosyphon system of solar heating of a residential building in Lviv has been established. The solar fraction of the hot water supply system of a residential building is determined depending on the volume of hot water consumed, in particular 50, 60, 70, 80, 90, 100 l/day. It is established that the lower the need for hot water, the greater the solar fraction of the solar hot water supply system. Thus, the average annual solar fraction of the solar hot water supply system with a daily consumption of 50 l/day is 0.77, and with a daily consumption of 100 l/day the solar fraction is 0.39. The average value of the solar fraction for the solar hot water supply systems of the studied house is 0.55.

Domestic Hot Water Consumption Profiles Applied to a Flat Tubular Collector for Solar Water Heating in Bogotá

The use of Flat Solar Collectors for the generation of Domestic Hot Water (DHW), facilitates access to this resource in an efficient, economical and sustainable way. The Sustainable Development Goals proposed by the UN, referring specifically to sustainable water management and access to renewable energy, are the main motivation for this work, since the former is an essential vital resource and its access reduces the inequality index, in developing countries such as Colombia, while the use of solar thermal energy reduces the environmental impact of the water heating process, thus reducing the consumption of electrical energy in the residential sector. Therefore, this work proposes to estimate DHW profiles through a spreadsheet that models the DHW flow thermodynamically for a whole year, making it possible to evaluate the energy performance of a Solar Collector available in the Colombian market and that is used in four types of dwellings located in the city of Bogotá. The simulation results present the DHW consumption profiles in kg/h per year, with DHW temperatures of up to 21°C, for a total transmitted irradiance of the order of 1100 W/m^2, which produces thermal energy close to 1kW. This comparative analysis allows us to review the technical and economic feasibility of solar collectors installed in single-family homes and with a DHW consumption profile close to the Colombian socio-economic reality