Tilt Angle Of Solar Collectors Research Articles

Optimization of solar radiation on tilted surface in isotropic and anisotropic atmospheric conditions

Solar energy is the main source of energy among all renewable energy sources and it can be harvested from various types of solar collectors and PV systems. The tilt angle of solar collectors and PV systems plays an important role in harvesting maximum energy from it. This research is concerned with the assessment of solar radiation and optimization of tilt angle at Delhi (28.61° N, 77.21° E), India. Optimization of the tilt angle has been done by two methods. The Liu & Jordan model has been used to assess the solar radiation for tilted surfaces under isotropic atmospheric conditions and the HDKR model has been used for total solar radiation assessment for tilted surfaces under anisotropic atmospheric conditions. Initially, partially differentiate HT for tilt angle and put it zero, then find out the tilt angle. After applying Taylor's series expansion method on the computed tilt angle. While applying to New Delhi, a measurable difference has been found in collected solar radiation. Assuming isotropic atmospheric conditions, a 55.3 % increment in monthly mean daily solar radiation has been found; whereas for anisotropic atmospheric conditions, an increment was evaluated by 57.7 % in December. Since monthly tilt angle adjustment is not feasible hence, this research proposed seasonal tilt angle adjustment. Maximum energy loss on seasonal adjustment is found at 4.07 % in autumn on considering isotropic atmospheric conditions. While considering anisotropic conditions a 4.51 % loss of energy is observed.

Design-Optimization of Solar-Collector Tilt Angle for Annual-Maximum and Seasonal-Balanced Energy Received

Abstract A detailed research study was performed on the annual energy received by a fixed-tilt solar collector. A new clear-sky model of solar radiation was developed by combining existing clear-sky models. Then, this model, was used to perform optimizations with two different objectives. The first objective is to achieve the maximum-annual solar energy received by a solar panel, while the second is to balance its energy received so that it is more uniform over the course of a year. Each of these objectives have differing optimum tilt values, depending on the location and usage of a solar receiver system. The novelty of this investigation is the use of the aforementioned solar model with a unique algorithm for multiple optimizations for these two different objectives, which results in two different optimum tilt angles that are in turn different from the widely accepted rule-of-thumb that recommends an angle that is equal to the latitude. The solar radiation results obtained with the model used herein were experimentally confirmed through comparison with measured weather data for a number of locations with different sky clearness indexes as well as comparison with those of other studies found in the literature. A major contribution of this study are the plots and tables showing optimum tilt angles as estimated by the model as well as with empirical data. By selecting the appropriate tilt angle, a designer can now decide to either maximize annual electrical energy production or else to balance delivery of electricity over the year.

Comparative Performance Analysis and Optimization of Acrylic Evacuated Tube Solar Collector with Water in Glass Tube Collector Through RSM

The dominant technique used to utilize solar energy to heat water for domestic, industrial, and commercial requirements is a solar water heater. This research work aims comparative performance analysis of acrylic evacuated tube solar collector with water in glass evacuated tube solar collector and also, to investigate the optimal value of process parameters affecting the performance of water in glass and acrylic evacuated tube solar collectors. In this research work, the intensity of solar radiation, tilt angle of the collector, and the time are considered as independent variables. The temperature difference of water of glass evacuated tube solar collector and acrylic tube solar collector is measured as a response. The input parameters are optimized by using CCD method in RSM for the maximized value of the temperature difference. The result of the experiment shows that optimal values of solar radiation 843 W/m2, tilt angle of solar collector 32.1°, and time period is 59.2 min are for maximized value of temperature difference of water 7.4°C for glass and 7.7°C for acrylic evacuated tube solar collectors respectively. The experimental result deviates 1.33% in glass and -1.3% in acrylic tube solar collector from simulated values.

Solar collector tilt angle optimization for solar power plant setup-able sites at Western Himalaya and correlation formulation

Tilt angle optimization of the solar collector is essential to achieve maximum power output. In this study, the performance analysis of monthly and yearly optimum tilt angles has been carried out for solar power plant setup-able sites in the Western Himalayan region of India. A mathematic model has been used for optimum tilt angle assessment. Annual average performance enhancement for monthly optimum tilt angles is 10–11%, 5–7% and 4–6% from horizontal, tilted at the latitude and tilted at an optimum tilt angle, respectively. Validation of the results has been carried out by mounting a polycrystalline PV panel at one of the suggested plant setup-able sites (ϕ30° 51′ 1.656′′, L 77° 3′ 41.508′′). The percentage variations found in experimental results are 8.85, 9.13 and 14.09 from horizontal, tilted at the latitude and tilted at yearly optimum tilt angle PV panel, respectively. To generalize the obtained result, correlations in terms of latitude and declination angle have also been formulated for yearly and monthly optimum tilt angles, respectively. The preciseness of the developed correlations has been validated by statistical tools. The results from this study have also been compared with the results of some previous studies, and good agreement has been obtained.

A LINEAR MODEL FOR DETERMINING THE OPTIMAL TILT ANGLE OF SOLAR COLLECTORS

Solar energy is transformed into electricity and thermal energy mainly by photovoltaic modules, and thermal collectors. To get the maximum energy throughout the year by these solar collectors, it is important to install the collectors in the correct (optimal) tilt angle from horizontal. There are different models for the determination of the optimal tilt angle of solar collectors. In this study, for practical use, the simple linear model for determining the annually averaged optimal tilt angles of solar collectors for any country in the world (for Northern and Southern hemispheres) are derived. In the proposed model, both the direct and diffused components of solar radiation are considered. The simple linear formula for the determination of year-round optimal tilt angles in Armenia or in any country with latitudes from 38 to 42 degrees of Northern hemisphere is also proposed. With the use of the proposed simple linear model the annually optimal tilt angles of solar collectors for the main cities of Armenia are determined. The obtained data are in excellent correlation with the results obtained by other accurate models. The proposed simple linear formulas can be successfully used to determine the optimal tilt angles of solar collectors.

A Theoretical Optimum Tilt Angle Model for Solar Collectors from Keplerian Orbit

Solar energy has been extensively used in industry and everyday life. A more suitable solar collector orientation can increase its utilization. Many studies have explored the best orientation of the solar collector installation from the perspective of data analysis and local-area cases. Investigating the optimal tilt angle of a collector from the perspective of data analysis, or guiding the angle of solar collector installation, requires an a priori theoretical tilt angle as a support. However, none of the current theoretical studies have taken the real motion of the Sun into account. Furthermore, a complete set of theoretical optimal tilt angles for solar energy is necessary for worldwide locations. Therefore, from the view of astronomical mechanics, considering the true orbit of the Sun, a mathematical model that is universal across the globe is proposed: the Kepler motion model is constructed from the solar orbit and transformed into the local Earth coordinate system. After that, the calculation of the optimal tilt angle solution is given. Finally, several examples are shown to demonstrate the variation of the optimal solar angle with month and latitude. The results show that for daily fixed solar collectors, the altitude angle of the collector should be about 6° above the noon solar altitude angle in summer and 6° lower in winter. For annual fixed collectors, the tilt angle should be slightly higher than the latitude. In summary, this study demonstrates that when a location is specified, this model can be used to calculate the theoretical optimum tilt angle of solar collectors for that position.

English

This paper deals with finding the optimum tilt angle of solar panels for solar energy applications. The objective is to maximize the output electrical energy of the photovoltaic (PV) modules. A mathematical model was used to determine the optimum tilt angle of solar collectors in Senegal on a daily and monthly basis, as well as for a specific period. Then, the configuration of the optimum tilt angle was analyzed by studying four specific cases in different typical climatic zones in Senegal. On a horizontal plane, the sun spends more time in the south than in the north. This means that in Senegal, the optimum tilt angle is often set equal to latitude. On the other hand, the optimum latitude angle is only for annual optimization. This study shows that the optimum tilt angle equal to latitude does not produce maximum output. For monthly optimum tilt angle, only the month of November gives tilt optimum angles equal to latitude. It is preferable to change the tilt angle of solar conversion systems monthly instead of fixing them, to gain more energy.   Keys words: Solar energy, solar panels, tilt angle, orientation solar panel, latitude, geometry.

Solar Chimney and Power Tower Techniques for Power Production in Nasiriya City

The solar chimney and power tower are two of modern promised energy which can develop bylow losses, simplicity and high power.In this paper, the solar chimney and fossil fuel power tower parameters are studied by usingtheoretical equations in computational fluid dynamics CFD that substituted in some computerprograms such as MATLAP and FLUENT codes with additional related expressions. Fivedifferent models are used in this paper (Chimney height is: 12, 15, 20, 25, and 35 meter),(Diameter of collector base is: 5, 8, 10, 15, and 20 meter). The effect of inlet collector height,collector absorbability, solar radiation, ambient temperature, solar collector thickness and solarcollector tilt angle are studied to find the other parameters and properties such as velocitydistribution, power and efficiency of system. The erecting of power turbine is predicted byfindings the velocity distribution between the base and chimney assembly. The numericalanalysis was presented by using GAMBIT and FLUENT 6.3 to predict that high velocity at theexpansion of chimney near the center of base – chimney bond position because of low density ofair as a result to solar radiation flux (and burned gases cover collector in case of using thechimney for combustion of gases in oil refineries).. This position is very suitable for promotingand building the power turbine. The maximum power accumulated from these techniques is morethan (6.7×105 Watt) where the velocity is (17.5 m/s). The study concluded that it is easy work toerect these chimney and power tower techniques closed to drilling and oil facilities in remoteareas. So, all factors were studied to coincide with previous papers in this field.

A review on solar flat plate collectors

Every year, energy demands and global warming are increasing due to the use of conventional energy sources. Hence, the need of the hour requires power to be produced by renewable sources, such as solar power. Even though solar collectors are commonly considered for low and medium temperature applications, their efficiency is low. Various research studies have been carried out in the effort to enhance the solar collector's performance. In this paper, an attempt is made to review the various research articles on analysis and optimisation models, nanofluids' usage and the tilt angle of solar collectors. This review will be beneficial for energy planners, academicians, scientists, and policymakers, to promote solar collectors for thermal applications for cleaner production and sustainable development.

Performance assessment of a solar powered hydrogen production system and its ANFIS model

Apart from many limitations, the usage of hydrogen in different day-to-day applications have been increasing drastically in recent years. However, numerous techniques available to produce hydrogen, electrolysis of water is one of the simplest and cost-effective hydrogen production techniques. In this method, water is split into hydrogen and oxygen by using external electric current. In this research, a novel hydrogen production system incorporated with Photovoltaic – Thermal (PVT) solar collector is developed. The influence of different parameters like solar collector tilt angle, thermal collector design and type of heat transfer fluid on the performance of PVT system and hydrogen production system are also discussed. Finally, thermal efficiency, electrical efficiency, and hydrogen production rate have been predicted by using the Adaptive Neuro-Fuzzy Inference System (ANFIS) technique. Based on this study results, it can be inferred that the solar collector tilt angle plays a significant role to improve the performance of the electrical and thermal performance of PVT solar system and Hydrogen yield rate. On the other side, the spiral-shaped thermal collector with water exhibited better end result than the other hydrogen production systems. The predicted results ANFIS techniques represent an excellent agreement with the experimental results. In consequence, it is suggested that the developed ANFIS model can be adopted for further studies to predict the performance of the hydrogen production system.

Empirical calculation of the optimal tilt angle for solar collectors in northern hemisphere

ABSTRACTPanel tilt angles (0°–90°) need to be in a proper position and location to get maximum productivity from solar energy. Values used in solar energy applications are generally computed by (global, diffuse, and direct) variation on horizontal surfaces calculated using isotropic sky and a mean albedo method. Being parallel to the available literature concerning such applications, this study focuses on the optimum solar panel angle. In this study, optimum solar panel angle value by months was determined for three sample provinces (Antalya, Kayseri, and Trabzon) first and North Hemisphere then. Capacity calculation of sample provinces was performed based on monthly, seasonal, and annual angle values and horizontal situation. Monthly and annual optimum angle values for Northern Hemisphere by 1° increase for between the latitudes of 1° N and 65° N. While the panel angle is at the highest level in autumn and winter (November-December-January and February) in annual process, the lowest angle is observed in spring and summer (May-June-July-August). Several different mathematical models have been developed for the sample provinces and Northern Hemisphere. While the variable of 12 different models that were developed for provinces is the Declination (δ) coefficient, the variable of 7 different models that were developed Northern Hemisphere is the latitude (Ø). Regional values in literature with estimation results of models were analyzed based on NASA and PVGIS data color scale. There was created a possibility of comparison by aligning all the optimum solar panel angle values of related location via a scale whose values vary by 1 and 10. Moreover, all the models were verified by statistical analysis methods. R2 (determination coefficient) in 19 different estimation equations is pretty close or equal to 1. However, the best among them is Eq. 32 (0.9979) for sample provinces and Eq. (33) (1) for the Northern Hemisphere; developed models are less-than-stellar. Other statistical data of these equations are MBE (−0.0616), RMSE (1.1176), t-sat (0.1830), Bias (1). For Eq. (32); MBE (1.96), RMSE (2.75), t-sat (8.13), MPE % (3.98), MAPE (5.87), SSRE (0.27), and RSE (0.06) for Eq. (33). The statistical analyzes indicate that all regression models are applicable in Turkey and Northern Hemisphere. Developed all correlations are recommended for academic and industrial users.

Residential solar water heaters in Brisbane, Australia: Key performance parameters and indicators

A multi-parametric sensitivity analysis of Solar Water Heater (SWH) systems was undertaken for the city of Brisbane in Australia using computational models calibrated by experimental data. The models were calculated using EnergyPlus 8.6. The following technical specification parameters were assessed in the modelling: (i) solar collector efficiency; (ii) solar collector area; (iii) tank volume; (iv) tank heat loss; (v) electric back-up heating power rate; (vi) electric back-up heating position (height) for vertical tanks; and (vii) electric back-up heating temperature range. The site-specific parameters included: (i) solar collector direction; (ii) solar collector tilt angle; (iii) solar collector shadowing; (iv) solar collector dust accumulation; (v) hot water pipe insulation; (vi) hot water pipe length; (vii) electricity tariff time-of-use; and (viii) cold water temperature. User behaviour patterns were comprised of the following parameters: (i) end-use water temperature; (ii) end-use water demand; and (iii) end-use time-of-use. For all parameters, two system types were assessed, namely: (i) thermosiphon systems with natural (passive) circulation in collectors and unstratified horizontal hot water storage tanks; and (ii) split systems with forced (pumped) circulation in collectors and stratified vertical hot water storage tanks. The performance of SWHs was analysed considering both energy performance indicators (i.e. total and peak-hour energy consumption, solar fraction and energy intensity) and level of service indicators (i.e. compliance with recommended hot water temperatures for Legionella spp. control and comfort levels). Notwithstanding the prevalence of thermosiphon systems among SWH technologies, results indicate that split systems usually outperformed thermosiphon systems both in terms of energy efficiency and level of service, and hence should be a preferred option for energy efficiency initiatives and policies.

Optimum tilt angle for solar collectors to receive maximum solar radiation in some Libyan cities

A simple model was developed to estimate the optimum angle to receive maximum solar intensity in five Libyan cities. It was found that It can be concluded from this study that we can use this model to estimate the annual and seasonal average optimum angle to receive maximum solar intensity in the Libyan cities depending on the latitude . This model can be applied to any other location

Modelling of Optimal Tilt Angle for Solar Collectors Across Eight Indian Cities

Solar-thermal applications require an illustrative knowledge of the solar radiation available in a particular location or region to enable efficient design and effectual utilization of solar energy. Due to the availability of meteorological stations only at few prominent places, the solar data estimated for other places depends largely on the latitude-based models proposed by various researchers, played a vital role in estimating the solar radiation data. In addition to this, the knowledge on proper orientation of the solar collector is a necessary parameter in the effective utilization of solar radiation to receive optimum radiation. In the present work, the optimum tilt angle for eight different cities across India is computed. The solar radiation received at various angles of tilt ranging from 1-90° is simulated and a yearly optimum tilt angle is determined for all the cities. From these results, a mathematical correlation to estimate the optimum tilt angle for any Indian city based on its latitude is proposed. The outcomes of this study will play a vital role in estimation and effective utilization of the freely available solar energy towards sustainable development of our nation.

Determination of the Optimal Tilt Angle of Solar Collectors for Different Climates of China

The tilt angle with the horizon (with respect to the ground) of the solar energy system affects the amount of solar radiation received. This paper suggests a simple and universal method to obtain the optimum tilt angles by estimating the monthly mean daily global solar radiation on tilted surfaces facing directly towards the equator, which is based on monthly average daily global solar radiation data produced from Typical Meteorological Year (TMY) data. The monthly, seasonal, and yearly optimum tilt angles for photovoltaic panels are calculated at six stations of different climatic types (Tropical Zone (TZ), Subtropical Zone (SZ), Warm Temperate Zone (WTZ), Mid Temperate Zone (MTZ), Cold Temperate Zone (CTZ) and Tibetan Plateau Zone (TPZ)). The results indicate that changing the monthly, seasonal, and yearly optimum tilt angles causes a significant yearly gain in the solar radiation for the region. In addition, general correlations are generated to estimate the optimum tilt angle of solar collectors at six typical climatic stations of China. The performances of the proposed models are compared using statistical error tests such as the mean absolute bias error (MABE), the root mean square error (RMSE) and the correlation coefficients (R).

Optimum tilt angle of solar collectors for building applications in mid-latitude zone

For the middle latitudes (mid-latitude) zone (latitudes between 23.45°N and 43.45°N and between 23.45°S and 43.45°S), as rules of thumb first solar collector should be orientated toward Equator and second it should have a latitude tilt value; however are these statements valid all over the year? The present work focuses on presenting an algorithm for determining the optimum tilt angle over mid-latitude zone and for any collector azimuth angle. Moreover, two simple approximate equations are proposed for predicting daily optimum tilt angle and optimum tilt angle for any number of consecutive months. The present algorithm was applied at different latitudes where data are available. The different yearly possible energy gains in relation that received by a horizontal surface were calculated. It is found that the yearly daily average energy gain for daily, monthly, seasonally and half-yearly adjustments are approximately constant. For the latitude of 43.45°N it reaches 1.7 times that of horizontal surface. So, it is sufficient from practical point of view to adjust the solar collector tilt angle twice a year: once on 22/3 and the other on 22/9. Moreover, the first rule of thumb is valid however the second one is not applicable for a large number of consecutive days in the year.

Comprehensive Analysis of Effect of Accumulation of Dust on a Solar Panel

In the pursuit of a cleaner and sustainable environment, solar photovoltaic (PV) power has been established as the fastest growing alternative energy source in the world. This extremely fast growth is brought about, mainly, by government policies and support mechanisms world-wide. Solar PV technology that was once limited to specialized applications and considered very expensive is becoming more efficient and affordable. Solar PV promises to be a major contributor of the future global energy mix due to its minimal running costs, zero emissions and steadily declining module and inverter costs. Deposition of airborne dust on outdoor photovoltaic (PV) modules may decrease the transmittance of solar cell glazing and cause a significant degradation of solar conversion efficiency of PV modules. Dust deposition is closely related to the tilt angle of solar collector, exposure period, site climate conditions, wind movement and dust properties. In this practical field study, an experimental-based investigation is conducted. Thus, we conducted a study to gauge the effect of dust on the solar panel over a pre-determined period.

Solar Receivers Optimum Tilt Angle at Southern Hemisphere

One of the important parameters that affects the performance of a solar collector is its tilt angle with the horizon. This is because the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector should be orientated towards the Equator with a tilt equal to latitude, valid for high latitudes region? Thus, it is required to determine the optimum tilt for Equator facing collectors. In addition, the question may rise: how much adjustments of Equator facing solar collector tilt angle is reasonable to do during a year? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector at any latitude. This model was applied for determining optimum tilt angle in the high latitudes zone in the Southern Hemisphere, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation up to 1.8 times of the case of a horizontal surface while the daily gain reaches 60 times approximately. Moreover, general formulas are proposed for predicting daily optimum tilt angle and optimum tilt angle over any number of days.

Comparison of optimum tilt angles of solar collectors determined at yearly, seasonal and monthly levels

The amount of energy that is transformed in solar collector depends on its tilt angle with respect to horizontal plane and orientation of the collector. In this article the optimum tilt angle of solar collectors for Belgrade, which is located at the latitude of 44°47′N is determined. The optimum tilt angle was found by searching for the values for which the solar radiation on the collector surface is maximum for a particular day or a specific period. In that manner the yearly, biannual, seasonal, monthly, fortnightly, and daily optimum tilt angles are determined. Annually collected energy per square meter of tilted surface is compared for ten different scenarios. In addition, these optimum tilt angles are used to calculate the amount of energy on the surface of PV panels that could be installed at the roof of the building. The results show that for observed case study placing the panels at yearly, seasonal and monthly optimum tilt angles, would yield increasing yearly amount of collected energy by factor of 5.98%, 13.55%, and 15.42% respectively compared to energy that could be collected by putting the panels at current roofs’ surface angles.

Determination of optimum location and tilt angle of solar collector on the roof of buildings with regard to shadow of adjacent neighbors

Solar systems have been widely used in recent years to supply some portion of buildings energy demands. Solar cells and flat collectors usually installed on the roof of buildings to keep away from the shade effects. Moreover, those must be installed incline at optimum angle to maximize the receiving energy. Determination of the optimum tilt angle of solar collectors is the subject of many investigations. These studies had supposed that, there is no barrier between the sun and collectors from sunrise since to sunset. In fact, any building may be surrounded by taller neighboring buildings. In these conditions, previous studies could not estimate the optimum tilt angle, truly. In addition, there are locations on the roofs which have more sunny time. These areas are more suitable for installation of collectors. Determination of optimum location and optimum tilt angle of solar collectors on the roof, with respect to the shadow of adjacent buildings is the main aim of this paper. Obtained results revealed that for earth's northern hemisphere, solar collectors should be installed on the southern edge of the roof as far as possible away from the taller neighboring building. If the roof is surrounded by two taller buildings, solar collector should be installed approximately on the center of the southern edge. Accordingly, received energy form the direct solar radiation on the optimum location could be increases more over the 15%. In addition, it was found that shade has minor effects on the optimum tilt angle for the parts of the roof near to the taller neighbor. In contrast, there is a considerable change of optimum tilt angle (up to 10°) for the farther regions form the taller neighbor.