Types Of Solar Collectors Research Articles

Design Analysis and Performance of Greenhouse Based Solar Dryer

Solar Drying or solar dehydration is one of the important processes required for preservation of food and agriculture products. Bacterial growth and moisture is being removed in this process. It helps for preserving the food products for more long time. Solar drying is the oldest & effective method used for drying food products. The device used for preservation of food products using solar energy is called as solar dryer or solar dehydrator. The solar dryer is classified on the basis of mode of drying, circulation of air, type and arrangement of solar air collector. In this project, a solar powered indirect type food dryer is designed and developed. The dryer design is consisting of solar collector unit along with absorber made up of extended surface of aluminum sheet with staging, drying chamber with three columns of each rack shelves, chimney for exhaust air, a solar powered fan. The dryer collector and drying chamber are connected with a hose pipe clamped to both ends. The project model of solar dryer is consisting of a monitoring unit for data logging of continuous updatation of parameters like temperature inside the dryer and temperature at ambient condition, humidity at inside and outside of dryer also the atmospheric pressure, etc. At the end we are going to investigate the effectiveness of solar dryer with above parameters.

Thermal Performance Prediction of Indoor Swimming Pool Solar Heating System Using Different Types of Flat-Plate Solar Collectors

The current study includes a theoretical study of the enfluence of different types of flat-plate solar collector on the solar fraction factor (ƒ) of a proposed solar heating system used for heating "alShaab Olympic Indoor Swimming Pool" located in Baghdad (Iraq) at a latitude of 33.32˚N. The swimming pool building has external dimensions of 95 m length, 51 m width, and 16.5 m height, it contains two pools, the first is for swimming with dimensions of (50 m * 21 m) with fixed depth of 1.8 m, the second is for diving with an irregular surface area of (351) m2 and with depth of 5 m. The Total thermal losses from the two pools to the pool hall and from the pool hall to the outdoor environment were calculated for four months of winter season (November, December, January and February) and a computer program was built using the MATLAB (R2008a) environment to solve the mathematical model equations in order to calculate the solar fraction facor (ƒ) of the proposed solar heating system at different solar collecting areas which are (2000,2500,3000,3500,4000,4500,5000,6000,7000,8000,9000,10000) m2 and at five different types of flat-plate solar collector which are (A: one cover black solar collector, B: one cover selective absorber solar collector, C: two cover black solar collector, D: two cover selective absorber solar collector, and E: pool absorber (PVC) solar collector). The results obtained showed that the highest values of solar fraction factor were obtained when using the solar collector type D, and the lowest values obtained when using the solar collector type E. The values of solar fraction factor (ƒ) of the proposed solar heating system, at solar collecting area of 10000m2 and at mass storage of water in the storage tank of 25 kg/m2 collecting area, for type D are 84.27 % for November, 72.74% for December, 69.4% for January, and 82.91% for February, and for type E are 56.14% for November, 41.15% for December, 37.17% for January, and 50.6% for February.

Experimental and simulation study of multichannel air gap membrane distillation process with two types of solar collectors

Solar thermal energy for membrane distillation desalination is a green and safe way for areas where water scarcity and solar irradiance are strongly correlated. In this paper, a commercial-scale of desalination plant was installed and tested to study the performance of a multichannel spiral-wound air gap membrane distillation module with an area of 14.4 m2. Air gap membrane distillation desalination plant at Port Said university was powered by solar energy using flat plate and evacuated tube collectors. The model validation was carried out. The solar desalination systems were numerically simulated using the program TRNSYS under different weather conditions throughout the year. The influence of the main operating parameters (feed flow rate and inlet temperatures of evaporator and condenser) was investigated. Regression analysis agreed with experimental data fitting using a quadratic polynomial model with coefficients of determination (R2) values of 0.997, 0.972, and 0.999 for permeate flux, outlet feed temperature, and outlet coolant temperature, respectively. The results showed that the permeate flux of the air gap membrane distillation with the evacuated tube collectors was 18.81%–30.44% higher than flat plate collector, and its cost was 22.48% lower. The specific thermal energy consumption of the air gap membrane distillation system ranged from 158.83 kWh/m3 to 346.55 kWh/m3. The maximum gain output ratio reaches 4.4 at 52 °C, depending on the feed inlet temperature. The thermal efficiency of the air gap membrane distillation system is 72%. The proposed air gap membrane distillation system produced 28.78 m3/year of fresh drinking water at a cost of USD 14.73/m3 with remarkable reducing in carbon dioxide emissions by 7,274.45 kg/year.

Process modeling and techno-economic analysis of a solar thermal aided low-rank coal drying-pyrolysis process

This study investigated the feasibility of integration of concentrated solar power (CSP) to low-rank coal pyrolysis process from the economic and technical perspective. Victorian brown coal is generally used in local power plants with low efficiency and great greenhouse gas emissions. Therefore, the development of low-emission technologies for an efficient use of such vast resources is paramount. The principal objective of this process is to upgrade Victorian brown coal to alternative fuels through a solar-assisted pyrolysis process. Upon a robust design of four different scenarios for the process integration, the effects of a variety of key variables have been examined, including different types of solar collectors, heat transfer fluids (HTF) and pyrolysis temperature. The plant operation analysis showed that integrating solar tower (ST) to provide heat for both coal drying and pyrolysis within the plant can save an average of 12.8% of the annual thermal energy demand. For the optimum solar tower design, it requires a solar multiple of 2, using carbonate salts as HTF, a design point DNI of 750 W/m2 and a heat storage capacity of 8 h to maximize its total solar energy output over a year. However, from an economical perspective, the use of solar tower for both drying and pyrolysis is economically infeasible. Instead, the parabolic trough solar collectors (PTC) designed to cover the heat required for coal drying only is most economically viable. It even shows a slightly better economic performance than the conventional pyrolysis process. The parabolic trough solar assisted pyrolysis process has the potential to reach a high net present value (NPV) of $81.1 million and a short payback period of 4.9 years, relative to an NPV of $52.8 million and a payback period of 5.1 years for the conventional pyrolysis process.

Theoretical Performance Study of an Indirect- Expansion Solar Assisted Heat Pump

This work presents a theoretical performance study of an indirect- expansion solar assisted heat pump SAHP. The theoretical analysis included a simulation of the IX-SAHP using TRNSYS software. These tests were conducted by varying the controlling parameters to investigate their effects on the thermal performance of the IX-SAHP such as the evaporating and condensing temperatures, compressor speed, refrigerant type and the solar collector area. A significant effect of the compressor speed on the thermal performance of the system is indicated. An increase of compressor speed causes a decrease of coefficient of performance COP. The performance of refrigeration system largely depends upon the characteristics of the refrigerants. COP was affected by the solar collector area and type where the COP increases with increasing collector area, but for a given heating load there is a required minimum solar collector‘s area, also evacuated tube solar collector lead to higher COP than flat plate collector for a given collector area. Compared to the conventional heat pump system, the present indirect expansion solar assisted heat pump system has the advantage that the collector can absorb the radiation and ambient energy and lead to increase the superheat level at the compressor inlet, so that reduced the work input of compressor in comparison to the conventional heat pump system.

Performance evaluation of energy storage system coupled with flat plate solar collector using hybrid nanofluid of CuO+Al2O3/water

Charging of energy storage system using flat plate solar collector (FPSC) is very popular in recent years. FPSC for the thermal energy storage system (TESS) using hybrid nanofluid was discussed in this manuscript. Hybrid nanofluid of CuO+ Al2O3/water was used as heat transfer fluid (HTF) for solar collector which is coupled with thermal storage and analysis carried out. To predict the thermal performance of energy storage system using hybrid nanofluid, a stainless steel container was used for thermal storage. CuO+Al2O3/water hybrid nanofluid were used to investigate the thermal performance of the solar collector and energy storage system. The FPSC is used for experimental investigation on the stainless steel container TESS. The flat plate solar collector is found more efficient than the other conventional type solar collector using hybrid nanofluid. The temperature of stainless steel container thermal energy storage system was reached to 87°C by using hybrid nanofluid in FPSC.

Numerical investigation of hydrothermal efficiency of a parabolic dish solar collector filled with oil based hybrid nanofluid

BackgroundParabolic Dish Solar Collector (PDSC) is a type of solar collector that heats a heat transfer fluid by concentrating sunlight on an absorber chamber and then passing a fluid stream through the absorber. Due to their extensive range of applications, enhancing their efficiency is very essential. Present study investigates the hydrothermal efficiency enhancement of a semi-cone parabolic dish solar collector filled with an oil based hybrid nanofluid. MethodThe studied geometry is a semi-cone shape parabolic dish solar collector equipped with smooth or corrugated absorber chamber. Two different heat fluxes are applied on absorber chamber and Eulerian-Eulerian two-phase model is employed for numerical simulation. The geometrical parameters of PDSC and corrugated plate are analyzed at various nanoparticles concentrations. FindingsAccording to result, utilization of nanofluid significantly augments the thermal performance of system. The exergy analysis shows that the growing of nanoparticles amount increases the convection coefficient and pressure loss, but it leads to higher exergy efficiency. Furthermore, the most optimum configuration PDSC is introduced.

Experimental Analysis on the Inactive region of Evacuated tube Solar Collector using Twisted Tapes

The evacuated tube type solar collector is used predominantly for water heating application in both residential and industrial scales. They found superior in thermal efficiency compared to other kind of solar collectors. All-glass evacuated solar collector is the simplest form of evacuated collector which found its major applications as passive flow solar water heaters for residential and industrial purposes. However, they have been affected with an inherent issue which is due to the inactive region formed at the bottom of the tubes. This paper addresses this issue with the help of twisted tubes, made-up of aluminum. The experimental results proved that the existence of twisted tapes accelerated the heat transfer within the inactive region and helped to maintain the uniform temperature inside the tube. The results proved that the water temperature at the inactive region was augmented up to 73°C with the help of twisted tapes, which was 31°C more than tubes without twisted tapes. Also, the twisted tapes enhanced the average temperature of tube water by the maximum of 10°C.

Natural convection of nanofluids in solar energy collectors based on a two-phase lattice Boltzmann model

In order to improve the photothermal conversion efficiency of solar energy collectors, the laminar convection of nanofluids in five types of solar energy collectors was numerically studied with a two-phase lattice Boltzmann model. In the current simulation, Cu–water nanofluids (volume fraction φ = 0.3%) were chosen. The equilibrium distribution function with D2Q9 model and the boundary conditions of nonequilibrium extrapolation scheme were applied to establish the lattice Boltzmann model. The effects of different Rayleigh numbers (Ra = 104–106), structures (rectangle cavity, trapezoid cavity and parallelogram cavity) and aspect ratios (A = 2:1, 4:3 and 1:1) of solar energy collectors on the heat transfer were considered. The temperature distribution, streamline and entropy generation of nanofluids in the solar energy collectors were analyzed. Results demonstrated that the increase in Rayleigh number heightens the heat convection of nanofluids. The trapezoid cavity and parallelogram have a special structure, which will form a flow dead zone, weaken the heat transfer effect and determine the position of maximum entropy generation.

Theoretical study on performance comparison of various solar collectors using binary nanofluids

The performances of three types of solar collectors using various nanofluids are theoretically investigated; further, by varying the concentration of binary nanofluids comprising of two highly efficient nanofluids, the performances of the solar collectors are analytically examined. The results obtained demonstrate that MWCNT, CuO, and Fe3O4 nanofluids show a higher efficiency compared with other nanofluids. Both MWCNT/CuO and MWCNT/Fe3O4 binary nanofluids provide efficiency enhancements in the range 2–50 %, 3–7 %, and 2–4 %, respectively, in flat plate, vacuum U-tube, and heat pipe solar collectors, compared with a 0.05 vol% MWCNT nanofluid. The use of binary nanofluids enhances the efficiency of solar collectors, which further increases with the concentration of the binary nanofluids. Furthermore, when the MWCNT/CuO binary nanofluid shows a higher efficiency than the MWCNT/Fe3O4 binary nanofluid in three solar collectors.

Techno-economic study of compound parabolic collector in solar water heating system in the northern hemisphere

Abstract The auxiliary requirement of a solar water heating system is an index of the end-user's cost and, thus, the feasibility of the system. Within this study several locations worldwide with high and low solar radiations and electricity prices in latitudes of 0, 15, 30, 45 and 60°N have been selected and the effect of employing a Compound Parabolic Collector (CPC) on the yearly auxiliary energy saving of a solar water heating system has been investigated numerically and compared with the energy performance of a typical flat plat collector. The yearly solar radiation in selected locations ranges from 2509 to 852 kWh/m2. Electricity prices also vary from 0.04 to 0.28 USD/kWh. According to results, in all selected locations, CPC shows an advantage over flat plate collectors in auxiliary power consumption. The yearly auxiliary heating rate decreased maximum by 27% in Shambat in Sudan and minimum by 5% in Chongqing in China. As solar radiation increases, the advantage of CPC becomes more meaningful. Regarding costs and economic feasibility of CPC, maximum net present values are all achieved in the locations with the highest electricity prices and not very high discount rates. Selected locations in Japan and Italy with maximum NPV values of 1,981 and 1,811 UDS, respectively, have the highest electricity rates of 0.28 and 0.27 USD/kWh, in respect. In both countries, the discount rate is relatively low and about 0.3. Moreover, among the selected locations, NPV of investment on CPC in Gabon, Guatemala, USA, Japan and Sweden with low levels of solar radiation, between 974 and 1,942 kWh/m2, is between 832 and 1,981 USD at the end of the project’s life time and justifies the employment of this type of solar collector in sites with high energy prices, even though not much solar radiation is available. It could be concluded that in locations with high electricity prices and not very much discount rates, even in cases of relatively low solar radiation, investment in CPC would yield the highest profits.

Unveiling the melting phenomena of PCM in a latent heat thermal storage subjected to temperature fluctuating heat source

Solar assisted thermal energy storage systems have gained potential over last few years. The present study investigates the melting behaviour of PCM in an enclosure under two different boundary conditions representing outlet temperature pattern of a solar collector and is compared with results of a baseline case with isothermal heating. Output temperature of a coaxial evacuated tube for two typical months have been used in the study and with this coupling of solar collector output and PCM, thermal energy storage of a particular type of solar collector is assessed. Lauric acid, an organic phase change material is used for the analysis. Conduction and convection both being equally important in such problems, Bejan's heatline concept is invoked to the current problem to study the heat flow in phase change materials which imparts novelty of the presented work. 2-D numerical simulations are performed to imitate the phase change process in virtual environment applying “effective heat capacity” method. In the modelling of the problem, natural convection is handled by taking into consideration of Boussenisq approximation and the velocity in solid region is restricted by the Darcy law's source term. Comparison with baseline case shows, the output of February month delivers fastest melting. The utility of the evacuated tube is also seen here as it extracts 11.35 kJ and 7.33 kJ more solar energy which is stored in phase change material. Heatlines are not explored much to analyse the heat transfer in phase change material in previous studies and in the present work one such attempt is made which effectively illuminates the conduction and convection regime. Interestingly it shows the re-emergence of conduction process at a later point of time in liquid PCM. The visualization of heat flow also reveals that the liquid region acts as heat source for solid PCM.

Review on solar collector systems integrated with phase‐change material thermal storage technology and their residential applications

This article reviews the design of solar phase-change energy storage systems and their applications in residential buildings. The solar thermal collection system has high heat collection efficiency, no pollution, and it is also widely used in the field of building heating. In order to improve the efficiency of the solar collector system, the researchers found that integrating phase-change materials (PCMs) into the solar thermal collector system can achieve this goal, but there will be a problem of PCM leakage. Some researchers have solved this problem by microencapsulating PCMs, the thermal conductivity and energy storage efficiency of the PCMs after microencapsulation will be greatly affected. Adjusting the solar collector to an appropriate inclination angle can achieve the highest heat collection efficiency. Choosing the PCM in the appropriate temperature zone can improve the system efficiency. For the separated solar collector system, the parts that need to be considered include the type of heat exchanger, the structure of the energy storage heat exchanger, the shape of the heat exchanger fins, the type of solar collector, and so on. All in all, coupling PCM into the solar collector system can improve energy efficiency reduce carbon emissions and have good economics, the maximum internal rate of return of solar collectors integrated with PCMs in residential and industrial applications is 22% and 17.2%.

Water-air regenerative heat exchanger with increased heat exchange efficiency

According to experts’ forecasts, by 2040 the global demand for energy will increase by 37%, and renewable energy sources in the next 20 years will become the fastest growing segment of the world energy, their share in the next decade will grow by about one and a half times. Solar energy is the fastest growing industry among all non-conventional energy sources and is gaining the highest rates of development in comparison with other renewable energy sources. In this article, the authors provide an overview of the technologies that increase the efficiency and productivity of solar panels, only the investigated methods are described that can speed up the process of introducing solar energy instead of traditional. All the methods described can increase the efficiency of systems that are based on the use of the sun as the main source of energy. The authors presented and described the scheme of a solar-air thermal power plant, which will improve energy efficiency through the use of a regenerative air solar collector with increased heat transfer efficiency. Strengthening will be achieved through the use of hemispherical depressions on the surface that receives solar radiation. A schematic diagram is given and the principle of operation of such a solar collector is described in detail. A comparative calculation of the intensification of the solar collector with the use of depressions and without the use as modernization was carried out, on the basis of which a conclusion was made about the efficiency of using this type of solar collector and the economic effect from the application of this method. A description of the method for calculating the solar collector is given, thanks to which this development can be used and implemented in existing heating and hot water supply systems.

Exergy based sustainability analysis of a dual fluid hybrid photovoltaic/thermal (PV/T) solar collector

This paper aims to investigate the exergetic sustainability index (SI) of a dual-fluid PV/T type solar collector that integrates both air and water into the same solar collector. The contribution of the exergy efficiency of each of the dual fluid PV/T collector's components to the overall sustainability of the whole system was analysed. A theoretical approach based on an experimentally validated numerical model was employed. The results show that the SI of the PV component of the dual fluid PV/T system is in general higher than the solar thermal component by approximately 9% since it is higher in quality. When evaluated under three different climatic conditions, the contribution of the thermal component as a cooling medium to the PV is only prominent in hot climates with SI higher by 4% compared to the stand-alone PV system. For the cool and cold temperate climates, the difference is less than 0.1%.

Exergy-based sustainability analysis of a dual fluid hybrid photovoltaic and thermal solar collector

This paper aims to investigate the exergetic sustainability index (SI) of a dual-fluid PV/T type solar collector that integrates both air and water into the same solar collector. The contribution of the exergy efficiency of each of the dual fluid PV/T collector's components to the overall sustainability of the whole system was analysed. A theoretical approach based on an experimentally validated numerical model was employed. The results show that the SI of the PV component of the dual fluid PV/T system is in general higher than the solar thermal component by approximately 9% since it is higher in quality. When evaluated under three different climatic conditions, the contribution of the thermal component as a cooling medium to the PV is only prominent in hot climates with SI higher by 4% compared to the stand-alone PV system. For the cool and cold temperate climates, the difference is less than 0.1%.

Investigation of the use of new solar air heaters for drying agricultural products

This article discusses the study of energy-saving technologies that have become a topical issue today. Types of solar heating collectors, the principles of operation, and their constructive structure were studied. A new technology developed based on the analyses proposed to dry the agricultural products. Also, in the current presentation, the technologies used in the context of the technologies and the reduction issues and technologies have been considered. Experimental experiments are also provided based on the proposed technology in seasonal (spring, summer, autumn, winter). In the study case, the operation principle of the operation of a flat surface air heater is studied. The article provides the basics of twice the shortening of air canals to a common full-length sunny air heater. The study learned the issues of reducing the local resistance ratio of the device concerning a common full-wide air heater. Raise the temperature of the sun's agents discussed in the article; reduction issues are analyzed.

Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages

Flat plate solar collector (FPSC) is commonly used due to its low price, less complexity, and easier installation and operation. The low thermal efficiency is the main disadvantage of this type of solar collectors. In the present study, the thermal performance of the FPSC using alumina oxide -water and copper oxide -water nanofluids are evaluated. The effect of nanoparticle volume fraction and nanoparticle type are investigated theoretically and validated experimentally. A computational fluid dynamic model is developed. The model is validated with experimental result carried in this study. The model is simulated under the hot climate conditions of Egypt. The results showed that the presence of the nanoparticles in the working fluid of the FPSC increases the pressure drop in the collector, but thermal performance enhancement is also obtained. Further, an optimum nanoparticles volume fraction of 0.5% of copper oxide nanoparticle is found to attain the highest thermal efficiency of the collector. Furthermore, using copper oxide-water nanofluid is effective than using alumina oxide-water nanofluid at the same conditions.

Convective Heat Transfer Inside Planar Solar Collectors

There is a permanent interest in improving the construction and thermal properties of the planar solar collectors. Minimizing the heat losses of the collectors and improving their energy gains are some of the relevant research goals. Convective heat transfer inside the cavity of planar collectors has been determined theoretically and numerically in this conference contribution. The convective heat transfer is computed on the basis of physical relations using the correlation relations of Nusselt’s number. The Nusselt number has been expressed by means of Rayleigh’s and Prandtl’s numbers. The convective heat transfer inside the cavities of planar solar collectors represents essential part of heat losses that lower the effectiveness of these collectors. In this conference contribution the convective heat losses have been compared with the standard density of heat flow coming from the Sun and the corresponding energy ratio has been determined. It has been shown that this ratio amounts almost 10 %. A typical summer environment has been supposed with a standard sunshine reaching 1000 Wm−2. The common type of the planar solar collector with geometrical dimensions 2m x 1m x 0.05m and cavity filled by air has been investigated. The temperature of the absorber has been supposed to be 70 °C whereas the temperature of the glass plate placed on the top side of the collector has been assumed to be 35 °C.

Improving the Performance of A Flat Plate Solar Collector Using Nanofluid as Working Fluid

Solar energy is the best alternative to limited fossil fuels. The foremost important means of utilizing solar energy are solar collectors. The most common types of solar collectors are flat plate solar collectors. A great deal of theoretical research has been conducted to enhance the flat plate solar collector efficiency. One effective way to increase the efficiency is by using an improved thermal properties fluid as nanofluid. In this paper, a numerical study has been made to enhance the efficiency and improve the performance of solar collector via the use of (Multi-Wall Carbon Nano Tube-water) MWCNT-H2O nanofluid instead of traditional fluid like water as working fluid under the weather of Mosul city / Iraq (36.3489° N, 43.1577° E). One dimensional dynamic model using implicit finite difference method was used. Solving energy conservation equations through the various layers of the solar system is the basis upon which the current model was based. Effects of nanoparticle volume fraction and mass flow rate on the working fluid stream temperature differences, and the thermal efficiency were studied. The mass flow rate was varied from 0.004 kg/s to 0.03 kg/s, while the volume fraction was varied from 0% to 6%. The results of "Nanofluid Based Flat Plate Solar Collector" were compared with the experimental results presented by [1]. The comparison established a good match between the current results and experimental results. The results showed an increase in the working fluid outlet and inlet temperature difference and collector thermal efficiency due to the addition of MWCNT nanoparticles. The temperature difference of "Nanofluid Based Flat Plate Solar Collector" was found 28.8⁰C at 0.014 kg/s and 6% in April, while it was 25 ⁰C at the same condition in the "Water Based Flat Plate Solar Collector case". Also, the thermal efficiency of "Nanofluid Based Flat Plate Solar Collector" was found 2.41% to 6.68% more than the "Water Based Flat Plate Solar Collector case".