Horizontal Collector Research Articles

Optimum Solar Collector's North-South Tilt Angles for Dar es Salaam and their Influence on Energy Collection

Solar collectors may receive significantly more solar radiation if some kind of Sun tracking is utilised. Optimal collector tilt angles, however, depend on the geographic location and other parameters including solar insolation for the site. In this study, daily, monthly, biannual and annual optimum tilt angles are calculated using a tilt angle-latitude relation model. The data are then used to obtain monthly and yearly optimum tilt angles through weighted averages considering the yearly fluctuations in solar radiation. The optimum annual tilt angle for Dar es Salaam is found to be 5.3° northwards, whereas biannual tilt angles due south and north are 10.5° and 18.9°, respectively. Analysis on the energy collection by a north-south tracking solar collector revealed an improvement of about 5% with optimum daily and monthly tilting, 4.3% with biannual tilting and about 0.8% with annual tilting, compared to a fixed horizontal collector. The results from this study provide optimal tilt angles for Sun tracking in Dar es Salaam and significant gain in energy collected by the solar collector may be realized through daily, monthly or biannual tracking of the Sun.

Assessment of Dust Deposition through Image Analysis in Complex and Remote Exhibition Sites: Study in the Cloister of the Santa María de El Paular Monastery in the Sierra de Guadarrama, Spain

Dust deposition is an important aspect of the conservation of heritage collections. Most proposed methods for dust monitoring focus on total area coverage or airborne concentrations. There is a lack of published data and methodologies to obtain size distributions of deposited particles on real historic sites. The purpose of the study was to develop and describe a method for obtaining quantitative data from dust deposition without the need for sophisticated laboratory equipment, based on optical microscopy photography and software-based image analysis. Bare microscope slides were used as passive collectors of dust. Tests were carried out on a collection of oil paintings displayed in the cloister of the Monastery of Santa María de El Paular in the Sierra de Guadarrama in Spain for one year, with a distance of 100 km between this place and the laboratory. The designed method allowed for the detection of significant differences in deposition depending on the location and seasonal period. Vertically orientated bare slides did not provide relevant information and a magnification of 50× was not really useful. However, horizontal collectors and a magnification of 10× allowed studying the deposition of particles above 2 μm2.

Thermal Diffusivity in the Subsoil: A Case Study in the Asturias (Northern Spain)

This study presents a novel methodology for determining the apparent thermal diffusivity of subsoil in situ, employing two heat transfer models within the subsurface: one method is based on heat conduction caused by air temperature oscillations, while the other considers heat transmission via both conduction and convection due to groundwater flow. Differential equations were solved, and non-linear regression analysis was employed. This method has direct applications in various engineering and environmental domains, such as underground transmission lines, oil and gas pipelines, radioactive waste management, and geothermal systems, especially in the context of implementing horizontal geothermal collectors (HGC). The apparent thermal diffusivity value of 1.514 × 10−6 m2 s−1, within a 95% confidence interval spanning 1.512 × 10−6 m2 s−1 and 1.516 × 10−6 m2 s−1, was obtained from the section between 1.67 and 3.86 m depth in a research borehole located in Asturias, Northern Spain, using twenty-one temperature sensors. The method allowed for the calculation of the subsoil’s apparent thermal diffusivity up to a depth of 14.55 m.

Numerical Modeling and Simulation of Rooftop Thermal Photovoltaic Chimney for Buildings' Electrical Energy Generation and Passive Cooling

The present study consisted mainly of making the thermal and dynamic analysis of the fluid flows in mixed convection in the chimney integrated into the building with an upper-covered horizontal hybrid thermal photovoltaic collector on a slab roof. The governing equations discretized by the finite difference method resulted in the systems of tri-diagonal algebraic equations, which were solved by Thomas' algorithm and Gauss Seidel's iterative method. Numerical solutions are presented for various geometrical aspect ratios, Rayleigh, and Reynolds numbers. The results are presented in terms of streamlines, isotherms, velocity, heat transfer intensity, and PV cells’ electrical efficiency versus the governing control parameters in detail.

Experimental and numerical analysis of a helically-coiled solar water collector at various angular placements

Solar water collectors are widely utilized for providing hot water to be used in different applications. In this work, a solar water collector with a helically coiled absorber has been designed, fabricated, and examined at different test conditions to specify its overall performance. One of the major goals of using a tube-type absorber is to upgrade the thermal efficiency of the collector by providing a perpendicular angle between the absorber and incident solar rays. Also, using a helically-coiled structure make it possible to increase the absorber surface in a relatively small volume in comparison to conventional solar water collectors. In the first step of this research, the designed helically-coiled solar collector has been simulated using a solar radiation model. In the next step, the manufactured helically-coiled solar collector has been experimentally tested at three different inclination angles and various water flow rates. According to the experimental results, mean thermal efficiencies of horizontal, vertical, and angular helically-coiled collectors were obtained in the ranges of 29.48–48.23%, 27.17–47.03%, and 32.50–52.71%, respectively. In addition, sustainability index values for horizontal, vertical and angular helically-coiled collectors were achieved between the ranges of 1.0041–1.0091, 1.0039–1.0087, and 1.0043–1.0102, respectively. Moreover, the maximum deviation between numerical and experimental findings was calculated as 14%.

Results of the calculation of the absorber temperature in a flat solar air heater

The article discusses a method for calculating the temperature of the solar air heater absorber under conditions of still air in the collector and under conditions of low forced convection. The problem of determining the temperature of the air heater absorber tst is considered for the climatic conditions of Fergana, with a horizontal collector and when solar radiation passes through double glass. It is assumed that over the considered short period of time, the temperature of the absorber is constant and the heat loss through the insulation of the bottom of the collector is negligible. Solar radiation passes through ordinary transparent colorless glass with a reflectance of 8%. Taking into account the losses of the heat flux of solar radiation when passing through glass 1 and 2 by the reflection coefficients K1 and K2, in the first version the Stefan-Boltzmann equation is solved, as a result of which the temperature value of the absorber surface is obtained. In the second variant, the absorber temperatures were obtained taking into account convection.

Design, commissioning and operation of a mini hybrid parabolic trough solar thermal power plant for direct steam generation

Parabolic Trough Collectors (PTCs) are the most mature, reliable and widespread among Concentrated Solar Power (CSP) technologies for electricity generation. The conventional power plants relying on PTCs use synthetic oil as Heat Transfer Fluid (HTF) which has limited life span, has limited operation temperature, is expensive and harmful to the environment. In the present research work, a new perspective has been developed to directly generate steam in the collectors, eliminating the need for HTF in the solar field and avoiding auxiliary heat exchangers. A mini hybrid Direct Steam Generation PTC power plant having a boiler as a backup that can be operated with biogas or natural gas is installed at Ecole Nationale d'Ingénieurs de Tunis (ENIT) within the framework of REELCOOP project (Renewable ELectricity COOPeration). The description, commissioning and operation of the solar plant are presented in this paper. The plant is designed and tested under real-life operating conditions in the south Mediterranean region. The feasibility of the DSG process in horizontal parabolic trough collectors has been confirmed and an important know how has been acquired regarding the operation of DSG solar plant. The main instructions for the operation of the solar plant have been presented including start-up and shutdown procedures of the plant, as well as the safety measures to be considered.The development of this plant is aimed to address the challenge of coupling intermittent solar radiation and the presence of a two-phase fluid in the absorber tubes. An important know how has been acquired regarding the operation of DSG solar plants in solar only mode and in hybrid mode which allowed to balance strengths and weaknesses of solar and biogas/natural gas technologies. By combining both systems, we have tackled the problem of the controllability of the energy supply while exploiting as much as possible renewable sources.

Emissions rate measurement with flow modelling to optimize landfill gas collection from horizontal collectors

A two-dimensional landfill gas flow model using the FEFLOW numerical code was developed to assess the potential improvement in landfill gas (LFG) collection and the reduction in greenhouse gas emissions at a landfill due to increases in the vacuum of horizontal collectors and/or installation of additional LFG collection infrastructure. A key calibration input parameter for the model, the fugitive methane emission rate from the study area, was measured using the airborne matter mapping method. The measurement showed that, at the time, the methane collection efficiency for the study area was approximately 37 %. The model indicated that increasing the vacuum of the existing collection system by 0.75 kPa could result in an improvement in collection efficiency from 37 % to 49 % within the selected study area. A similar increase of collection efficiency could be obtained by either doubling the number of horizontal collectors on a platform or installing a layer of permeable demolition waste on that level, without an increase in collection system vacuum. Combining the addition of collection infrastructure with an increase in collection system vacuum by 1 kPa was predicted to improve the collection efficiency for the study area to about 74 %.

ЕФЕКТИВНІСТЬ ТЕПЛОПЕРЕДАЧІ У ГОРИЗОНТАЛЬНОМУ КОЛЕКТОРІ SLINKY ІЗ НАНОРІДИНОЮ “ВОДА – Al2O3”

The heat transfer of the “water – Al2O3” nanofluid in the Ø 32 × 3 mm horizontal Slinky collector of spiral configuration of a heat pump have been studied. Nanofluid has good characteristics for use in the energy sector due to its high thermal properties. Studies were performed in the range of changes in the concentration of nanoparticles from 0.38 to 1.3 % vol. for the energy system of an energy-independent building, in particular, for the heating and non-heating periods of the heat supply system for the Kyiv region.

Survey of 53 Fifth‐Generation District Heating and Cooling (5GDHC) Networks in Germany

Fifth‐generation district heating and cooling (5GDHC) networks are a promising technology to decarbonize the heating and cooling supply of buildings and districts. Up to today, only a small number of 5GDHC networks have been built, mostly in Switzerland and Germany. As a result, there are substantial uncertainties and knowledge gaps in the planning and operation of 5GDHC networks. Herein, a survey is conducted among utility companies and engineering offices to collect data on 53 5GDHC systems in Germany, including technical, economic, and political key figures and design decisions. Results show that 5GDHC networks are mostly planned for small new build districts (less than 100 buildings). The most frequent heat sources are horizontal geothermal collectors (used in 23 networks) and geothermal probes (17 networks). 74% of the surveyed networks provide not only heat but also cold. Typical network temperatures are in the range of −5–20 °C. The survey results show that the price models as well as political design decisions, such as the obligation to connect to the network, vary strongly among the districts.

An Assessment of the Effectiveness of Riverbank Filtration in a Sewage Plant Effluent-Impacted River Using a Full-Scale Horizontal Well

From 2014 to 2020, a full-scale horizontal well was operated to investigate the performance of full-scale riverbank filtration (RBF) in the Nakdong River in Korea, which is significantly impacted by the effluents from sewage treatment plants. In this study, an individual lateral full-scale horizontal collector well was investigated for the first time in Korea, and its performance was determined based on the turbidity and levels of iron, total nitrogen, dissolved organic matter, and four selected trace organic contaminants (TrOCs) (tebuconazole, hexaconazole, iprobenfos, and isoprothiolane) in the RBF and Nakdong River. The turbidity of the river was high with an average of 10.8 NTU, while that of the riverbank filtrate was 0.5 NTU or less on average. The average dissolved organic carbon (DOC) concentrations were 2.5 mg/L in the river water and 1.4 mg/L in the riverbank filtrate, which indicated a 44% reduction in DOC content during the RBF. Out of the 10 laterals, 8 laterals exhibited similar levels of iron, manganese, total nitrogen, DOC, and total hardness, electrical conductivity, and turbidity. The characteristics of the remaining two laterals were different. Because the groundwater inflow was relatively low (<10%), the laterals were contaminated by agricultural land use before the installation of the RBF. This is the first study to report changes in water quality according to individual laterals in a river affected by wastewater effluents. The filtration unit exhibited more than 90% removal rates for tebuconazole and hexaconazole. However, the removal rate for iprobenfos was approximately 77%, while that for isoprothiolane was 46%. The four selected TrOCs in this study were not detected in the groundwater. We found that some organic micropollutants were effectively removed by the RBF.

Review: Horizontal, directionally drilled and radial collector wells

Horizontal wells play an often overlooked role in hydrogeology and aquifer remediation but can be an interesting option for many applications. This study reviews the constructional and hydraulic aspects that distinguish them from vertical wells. Flow patterns towards them are much more complicated than those for vertical wells, which makes their mathematical treatment more demanding. However, at some distance, the drawdown fields of both well types become practically identical, allowing simplified models to be used. Due to lower drawdowns, the yield of a horizontal well is usually higher than that of a vertical well, especially in thin aquifers of lower permeability, where they can replace several of the latter. The lower drawdown, which results in lower energy demand and slower ageing, and the centralized construction of horizontal wells can lead to lower operational costs, which can make them an economically feasible option.

Hydraulic testing of specialised water production structures (horizontal collector well) in riverbank filtration systems

One of Hungary's strategic water sectors is the supply of drinking water, which relies heavily on so-called riverbank filtration systems. About 35-40% of the national drinking water supply comes from riverbank filtered aquifers. Today in Hungary, 40% of the population; nearly four million people's daily water needs are met from riverbank filtered aquifers. In the future, 75% of our drinking water sources will be bank-filtered, which means that they will also be of great importance for future water resource management. The main water abstraction device in these aquifers is the well, or a special type of well, the horizontal collector well (HCW). In our work, we will focus on the hydraulic investigation of these types of wells. Using modern modeling software, the impact of the special design of HCWs on groundwater flow conditions can be well modeled. In our work, the yield distribution between the arms and the impact on the potential relationships are discussed in more detail and the results of this modeling are presented.

Use of water-TiO2 nanofluid in horizontal slinky collector of heat pump

The hydrodynamics of water-TiO2 nanofluid in the Ø32×3 mm horizontal Slinky collector of the heat pump, as well as the heat transfer from river water to the nanofluid have been studied in the paper. Water-TiO2 nanofluid provides attractive opportunities of the application in the energy industry due to its enhanced thermal properties. The thermal and hydrodynamic characteristics of the heat transfer fluid with spherical TiO2 nanoparticles in the temperature range from 2 to 12.5 °C have been analysed. The numerical studies have been performed within the range of change in the nanoparticles concentration from 0.3 to 1.3 vol. %. The influence of operating temperatures of water-TiO2 nanofluid on the efficiency of the energy system of a self-sufficient house, in particular, during the heating and non-heating seasons of the heating system operation for Kyiv region has been studied. The paper provides recommendations and confirms that the limitation of the practical use of water-TiO2 nanofluid is the increase in the viscosity of the heat transfer fluid, accompanied by the increase in power for its transportation. The calculated dependencies of the performance efficiency coefficient of water-TiO2 nanofluid application in the energy system on the content of nanoparticles in the heat transfer fluid have been obtained.

Analytically Supported Numerical Modeling of Horizontal and Radial Collector Wells

AbstractRiverbank filtration (RBF) is widely used in drinking water production all over the world. The horizontal and radial collector wells are among the most important water production facilities...

A 3D numerical study to evaluate optimum collector inclination angle of Manzanares solar updraft tower power plant

In this paper, a three-dimensional turbulent study was carried out on Manzanares (Spain) plant to study the effects of collector inclination angle (θ). Different ranges of θ (30–0°) with more than 15 models were considered for the analysis. An optimized θ has been proposed based on the estimated parameters such as air velocity, pressure drop, absorber and air temperatures, power developed, collector efficiency, and overall efficiency (ηcoll and ηo). At θ = 6°, an increment of 9.16% in theoretical power (Pth) and a 10.68% increase in air velocity were observed at the chimney base (CB) compared to the horizontal collector plant. Any further increase in θ (greater than 7°) resulted in recirculation of air particles within the collector canopy, leading to obstruction of flow. Any value of θ lesser than 6° resulted in a drop in the major outputs such as Pth, ηcoll, and ηo. Eventually, θ = 6° has been proposed as optimized inclination. The dynamic pressure difference was maximum at a chimney height of 2.5 m from CB; therefore, this was the preferred location for turbine fitment. The results were compared with the experimental data of the Manzanares plant, and a very favorable agreement was noticed.

Numerical analysis of porous flat plate solar collector under thermal radiation and hybrid nanoparticles using two-phase model

Solar collectors will play a very important role in absorbing solar renewable energy for use in various industries in the future of the world. This study looks at the resulting combination of using porous medium and hybrid nanofluids, in the presence of thermal radiation, on the thermo-hydrodynamic features, heat transfer, supply temperature, and hybrid nanoparticles’ distribution within a horizontal flat plate solar collector. The two-phase approach is considered for modelling. The migration of Ag-Al2O3 hybrid nanoparticles due to the Brownian motion and thermophoresis effects was also taken into account. The set of governing equation was numerically solved employing the finite element method. The investigation is performed by reporting the roles of hybrid nanofluid concentration, porosity coefficient, Darcy number, Reynolds number, porous media to hybrid nanofluid thermal conductivity ratio, Brownian motion parameter, thermophoretic parameter, radiation parameter, and Schmidt number. The results indicate that The high values of porosity coefficient, radiation parameter, conductivity ratio, and thermophoretic parameter ameliorate thermophoresis effects, and therefore, a high concentration of nanoparticles was observed near the bottom part of the collector, especially at low Reynolds. Also, Employing hybrid nanofluid lead to a decrease in the heat transfer rate and slightly raised the supply temperature at low Re.

Assessment of an alternative Pinctada margaritifera spat collector in French Polynesia

Plastic waste in the oceans is a growing concern due to its size diversity, its ubiquitous nature and its impact on both marine organisms and ecosystems. While threatened by this marine plastic litter, the aquaculture industries also represent one of its major sources. In French Polynesia, black-lip pearl oyster (Pinctada margaritifera) farming is no exception. Wild spat collection has been described as a source of pollution because of the numerous particularly fragile and brittle shade-mesh plastic collectors used locally and often mismanaged when no longer usable. Thus, with the aim of helping to reduce this pollution, the present study is focused on the assessment of reusable plate collector as a potential alternative. We tested, using an in situ approach, the influence of the collecting surface position (i.e. horizontal vs vertical), plate color (i.e. black vs orange) and density (i.e. 25 plates vs 50 plates) on Pinctada margaritifera and Pinctada maculata spat settlement. Our results showed that 50-plates collectors, whatever their color and position, were more efficient to collect both kinds of spat than shade-mesh collectors (P < 0.0001). They also induced a higher number of Pinctada margaritifera spat than on the 25-plates collection device although there was no significant difference in numbers of Pinctada maculata spat (P < 0.0001). However, every type of plate collector presented a decreased mean length of the spat collected (P < 0.0001) compared to the shade-mesh collector. Furthermore, horizontal positioning of the collecting surface greatly improved the spat numbers on plate collectors (P < 0.0001) although there was no effect on shade-mesh collectors (P > 0.05). Finally, our results indicated that, among all the devices tested, the black horizontal 50-plates collector was the most efficient to collect spat and particularly Pinctada margaritifera. These first findings thus tend to suggest that these black re-usable plate collectors could be an efficient alternative to the currently used shade-mesh collectors.

Upotreba solarnih postrojenja za sušenje semena useva

A grain drying complex based on solar energy, including a grain storage with a built-in solar drying system and a drum solar dryer for grain, is proposed. The construction and principle of operation of the grain drying complex is described. The basis of each of the solar drying systems of the complex is the presence of two solar collectors, one of which provides heating of the drying agent at the inlet into the drying chamber, and the second-heating of the used drying agent in the exhaust pipe to increase its flow rate and, accordingly, the intensification of grain drying. Availability of gravel or water heat accumulators allows to carry out the process of grain drying or grain storage, at night and under adverse weather conditions without the risk of self-heating. The optimum capacity of the gravel accumulator is 0.5-0.75 m 3 per 1 m 2 of solar collector area. Drum solar dryer provides guaranteed drying of a grain batch for 6-7 hours of the day time and a grain batch for the night time. It was found that the optimum thickness of the grain layer in the drying process is 50-70 cm and specific load is up to 100 kg of grain per square meter of the horizontal solar collector area.

Development of production technology of rolling stock cast parts

Using the computer simulation program ProCAST, the analysis of the processability of the gating system used in the current production of the SK “Foundry-Mechanical Factory” in the manufacture of large cast parts of railway rolling stock was performed. Based on computer modeling, a new design of a gating system with a dispersed metal motive with different sizes of feeder sections was developed, providing simultaneous parallel filling of all parts of the mold cavity. The feature of the proposed design of the gating system is the presence of an extended horizontal collector and the supply of metal to the end parts of the casting. With this design, two counter-flows are formed in the mold cavity, their fusion occurs in the middle part of the casting in a cooled and highly polluted state, since during the filling process, the head part of the flow collects sand inclusions along the way, is oxidized and saturated with hydrogen. These factors are a prerequisite for the formation of various defects in castings.