Collector Inclination Angle Research Articles

An experimental study on parabolic trough solar cookers with materials collector of chrome stickers and glass mirrors

Cooking, a fundamental human necessity, frequently relies on environmentally harmful energy sources. Concentrated solar power offers a promising solution through solar cookers to address this issue. This study assesses a Parabolic Trough Collector (PTC) solar cooker's performance with two reflector materials: chrome stickers and glass mirrors. The PTC-type solar cooker comprises essential components, including an absorber tube, a flexible conduit, and a spiral-shaped cooking container holder that accommodates a diverse range of cooking vessels. In the configuration of the PTC collector, reflectors fabricated from chrome stickers and glass mirrors are strategically employed to harness and concentrate solar radiation effectively. The absorber tube, crafted from copper, is filled with a heat-transfer fluid consisting of soya oil. Experimental investigations were conducted in a two-stage process, encompassing trials without any applied load and subsequently with varying loads. In the no-load experiments, alterations were made to the PTC collector's inclination angle, spanning the ranges of 15º, 20º, 25º, and 30º. In contrast, the load-bearing tests encompassed the assessment of the PTC solar cooker's performance under a diverse array of cooking scenarios, including boiling water, heating oil, frying eggs, and crisping crackers. The evaluated parameters encompassed key metrics such as incident solar radiation (Ir), ambient temperature (Ta), receiver temperature (Tr), fluid temperature (Tf), spiral furnace temperature (Tsf), and load temperature (To). Subsequently, the outcomes of the experiments were employed to determine the efficiency of the solar cooker. Analysis of the no-load test results indicates that the most favorable performance, as observed in the parameters Tr, Tf, and Tsf, is achieved at a collector inclination angle of 15º for both chrome sticker and glass mirror reflector materials. The solar cooker demonstrated commendable proficiency in boiling water, heating oil, frying eggs, and crisping crackers, accomplishing these tasks within a time frame ranging from 5 to 20 minutes. Notably, the solar cooker featuring the glass mirror reflector exhibited a superior thermal efficiency of 33.7%, surpassing the efficiency of the counterpart with the chrome sticker reflector, which registered an efficiency of 30.9%. These findings underscore the efficacy of the glass mirror reflector in harnessing solar energy for enhanced cooking performance within this solar cooker configuration.

Sensible heat thermal energy storage performance of mono and blended nanofluids in a free convective-radiation inclined system

The photothermal conversion performance (PCP) of a nanofluid-based solar energy system is investigated numerically and experimentally. The impacts of particle size, volume concentration, nanoparticle type, base fluid type and collector inclination angle on the PCP are investigated. It is observed that using nanoparticles improves the ability to absorb solar energy. Temperature gain is 2.2, 3.2, 3.8, 4.2, and 9 times better than pure water for water-based Al, Al2O3, Au, Cu, and Graphite mono nanofluids, respectively. Interestingly, blended nanofluids containing the same nanoparticles significantly argument the optical properties, with useful heat enhancement ranging from 62.8 (mono) to 194 kJ/kg (hybrid). However, the collector's inclination angle, which ranges from 0 to 60°, has a negative impact on the PCP by reducing the solar radiation absorption of the nanofluids due to a decrease in the radiation penetrating the collector. Furthermore, as nanoparticle size increases, so does the thermal performance of the nanofluid. An experimental investigation is carried out for pure water and nanofluid at various wind speeds and solar irradiation levels ranging from 1 to 4 m/s and 200–1000 W/m2, respectively, to validate the numerical results.

벽체일체형 강제순환 태양열온수기의 열성능 평가 (제2보: 시뮬레이션)

In general, flat-plate solar collectors are installed at an angle of 30° or 45° for the best annual thermal performance. Through experiments in previous studies, it was confirmed that the building integrated forced circulation solar water heater was good in thermal performance. However, it is necessary to compare under the same conditions with the 30° and 45° collectors, which were used much more popularly. In this study, it was impossible to experiment with the same environment, so simulation was conducted. Simulation was performed with TRNSYS18, and the simulation model was verified by comparing it with experimental data. As a result of simulation, in the order of 30°, 45°, and 90° of collector inclination angle, the collection efficiency in the winter season was 37.6%, 38.6%, 39.2%, and the solar fraction was 54.2%, 50.3%, 48.1%, respectively. The performance in summer when the load for hot water supply is small is significantly lower than other inclination angles, but there is little risk of overheating due to the low system temperature.

An Experimental Study on Performance Assessment of Solar Updraft Tower Power Plant with Guide Vanes

Solar updraft tower (SUT) plant is one of the viable passive energy technologies for carbon-free power generation. However, the lower thermal performance of the plant is still a major huddle for its global acceptance. The main aim of the present study is to improve the performance of the plant by providing guide vanes inside the canopy. A SUT plant was developed, where the height of the chimney, collector inclination angle and diameter of collector were 6 m, 30° and 3.5 m, respectively. The flow and performance parameters of the plant were measured and analyzed. Two distinct scenarios such as Case1: the SUT plant and Case2: Case1 with guide vanes were studied. It was observed that the flow and performance of the system were enhanced significantly in Case2 compared to Case1. The maximum hourly average velocity at chimney base and maximum theoretical power potential were enhanced by 9.4 and 10.7%, respectively, at 13.30 h for Case2. For the study period of 13 h, the overall efficiency of the SUT system was enhanced by 46.7% in Case2 compared to Case1.

CFD and exergy analysis of subcritical/supercritical CO2 based naturally circulated solar thermal collector

Solar water heating system is inefficient during winter due to the chances of water freezing and higher viscosity at low temperatures. Several investigations are being done to increase the efficiency of the solar water heater using various secondary fluids for different climatic conditions. This paper emphasises on the study of heat transfer and fluid flow behavior of CO2 based naturally circulated indirect solar water heating system. Subcritical (liquid and vapour) and supercritical CO2 are considered as loop fluid, and the results are compared with water based system. Three-dimensional computational fluid dynamics simulations are carried out for two different weather conditions i.e., winter (278 K) and summer (305 K). Results are obtained for 33° collector inclination angle from horizontal at various operating pressures 50–70 bar for subcritical and 80–100 bar for supercritical CO2. The CO2 based system yields very high Reynolds number (subcritical liquid: ∼160 times; subcritical vapour: ∼204 times; supercritical vapour: ∼260 times) and very high Nusselt number (subcritical liquid: ∼14 times; subcritical vapour: ∼19.5 times; supercritical vapour: ∼48 times) compared to water based system. Supercritical CO2 based system exhibits 12% higher energy efficiency compared to water. Whereas, subcritical vapour based system exhibits 140% higher exergy efficiency relative to water based system.

Heat collection performance analysis of corrugated flat plate collector: An experimental study

Heat collection through flat plate collector is a common technology in solar thermal utilization. In order to improve the heat collection efficiency of flat plate collector and determine the best inclination angle and glass plate thickness, this paper establishes a collector indoor experimental system, and completes the research of solar radiation intensity, collector inclination angle, mass flow rate and glass thickness on the heat collection performance of corrugated flat plate collector. The result shows that when radiation intensity is 510W/m2, the temperature difference between the inlet and outlet in the radiation decreasing stage is 0.25 °C higher than the radiation increasing stage, and the heat collection in the radiation decreasing stage is 157.5W higher than the radiation increasing stage. The heat collection efficiency under different inclination angles decreases with the increase of radiation intensity, the best inclination angle of the collector is 45° and the maximum heat collection efficiency is 0.89. When the radiation intensity is more than 1000W/m2, heat collection of flat plate collector with glass thickness of 8 mm is 6% higher than that with the thickness of 6 mm, insulating effect of the glass is more obvious. The optimum thickness of the glass plate is 4 mm, the maximum temperature difference is 1.5 °C and the maximum heat collection efficiency is 0.89. The heat collection efficiency at different mass flow rates increases first and then decreases with the increase of radiation intensity. The maximum value of the heat collection efficiency at low mass flow rate is delayed. When the mass flow rate is 0.15 kg/s, 0.13 kg/s and 0.1 kg/s, the maximum heat collection efficiency is 0.89, 0.86 and 0.73, respectively; and the corresponding radiation intensity are 670W/m2, 850W/m2 and 1000W/m2, respectively.

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.

Shading and Masking of PV Collectors on Horizontal and Sloped Planes Facing South and North—A Comparative Study

With the increase in PV system installations, the available free land and rooftops for these systems may become scarcer, and therefore sloped fields facing the north may be utilized for that purpose. In deployments of PV collectors in multiple rows, either on horizontal or sloped planes, the second and subsequent rows are subject to two effects: shading and masking. Both effects reduce the electric energy generated by the PV systems. Multiple rows of collectors are deployed on horizontal planes and on sloped planes facing south, and literature on the topic has been published. No literature deals analytically with deployments of PV fields on north-facing slopes in the northern hemisphere, to the best of our knowledge. The present study develops explicit analytical expressions for the shadow height and length cast on a collector row by a row in front in multiple-row PV systems installed on slopes facing north. In addition, analytical expressions are developed for row spacing and sky view factors, altogether leading consequently to the determination of shading and masking losses. Having the developed expressions, a comparison was made between PV deployments on north-facing sloped planes to PV deployments on horizontal and south-facing slopes regarding shading and masking losses. The main finding is that the percentage of masking losses (diffuse radiation) may exceed the percentage of shading losses (beam radiation) in PV fields. At the local site 32∘ N, collector inclination angle β=25∘ and sloped-plane ε=10∘, for example, the percentage of masking losses for a horizontal plane is 6.90%; for a sloped plane facing south, the losses are 5.39%, and for a sloped plane facing north, the losses are 6.86%. In comparison to the masking losses, the percentage of shading losses for the horizontal plane is 0.83%; for the sloped plane facing south, the losses are 0.42%, and for the sloped plane facing north, the losses are 1.37%.

Outdoor Testing of a Zig-Zag Solar Air heater with and without Artificial Roughness on Absorber Plate

In this paper, thermal performance of a zig-zig solar air heater (ZZSAH) with and without using steel wire mesh on the absorber plate of the collector is experimentally investigated. The experimental work includes four inclination angles of the collector 20o, 30o, 45o, and 60o and four air mass flow rates of 0.03, 0.04, 0.06, and 0.08 kg/s under varieties of operating conditions of a geographic location of Baghdad. New correlation equations of Nusselt number are obtained from experimental results for both types of collectors where the effect of varying of the inclination angle of collector taken into consideration in the experiment. The correlations show good agreement with the present experimental data. In addition, the effects of mass flow rate and temperature rise across the efficiency of collector air heater are investigated. The results reveal that the efficiency of (ZZSAH) at 45o inclination angle reaches the highest values among other degrees of inclination angles for both types of collectors under study. The results also show that the addition of wire mesh magnifies the effect of inclination angle.

Performance Analysis of Flat Plate Solar Collector using Al2O3/Distilled Water Nanofluid: An Experimental Investigation

Owing to how effectively it can convert solar energy into usable form, solar thermal technology has gained a lot of importance during the recent years. Heat exchangers, refrigeration, air conditioning, material science engineering, etc. are the biggest proponents incorporating solar technology along with nano particles for their high thermal conductivity. This study concerns with the effect of water based Al2O3 Nano fluid on the performance of solar water heater- Flat plate type. In the study, the dispersion quality of nanoparticles in fluid was enhanced using high quality surfactant sodium dodecyl sulfate (SDS). The experiments were conducted at Amity University Rajasthan, Jaipur, India (27.1721° N, 75.9542° E) which has an annual average solar irradiance 5.56 kWh/m2/day. Different conditions like flow rate, pressure, climatic conditions, time, solar collector inclination angle, composition of Nano fluid etc. were tested. The Al2O3 concentration varied from 0.1 to 0.3 vol. percentage. The tests were performed at different mass flow rates 1-3 LPM. The measured values of the thermal conductivity in the range of 0.610-0.622 W/m-k. Results indicated that by increasing the volume fraction of Al2O3 from 0.1% to 0.3%, there is a 21.32% growth in collector efficiency

EXPERIMENTAL STUDY FOR GROUND TYPE EFFECT ON SOLAR CHIMNEY POWER PLANT

Solar chimney power plant is a technology capable to generate electric energy through a wind turbine using the solar radiation as energy source; nevertheless, one of the objectives pursued since its invention is to achieve energy generation during day and night. The ground under the power plant plays an important role on the energy balance and heat transfer, due to its natural behavior as a heat storage system. An experimental model was designed in Holley Kerbala city (Iraq), which consisted of a 3m collector radius with 8ᴼ collector inclination angle and a 6m height of chimney been constructed and collector periphery opening height 3cm. Three kinds of grounds was studied in this work: sand, mixed from sand and pebble and the third is black pebble. The results show that the highest airflow temperature inside the chimney reached was 66.8Co when using the black pebbles basement. The maximum basement temperature measured was 81.6Co for the mixed basement. Also, the highest temperature difference reached was 23.2Co for the same ground that have good performance during day light compared with pebble basement that have more energy saving in night.

Performance analysis of solar chimney using mathematical and experimental approaches

A mathematical model based on one-dimensional energy and mass balance across the solar chimney has been developed. The air flow characteristics such as exit velocity and temperature are evaluated with respect to the collector inclination angle, hourly solar radiation, ambient temperature, and wind speed. The model is validated by comparing the performance parameters obtained, with the experimental results and also with the experimental data of different geometrical range and environmental conditions from the literature. An average deviation of 8% for exit air velocity and 1.35% for exit air temperature is obtained for the solar chimney with absorber inclination angle 30°, collector area 0.41 m2, and chimney height 0.24 m. The experimental daily average and maximum exit air velocity during the month of April are 0.5 and 0.88 m/s, respectively. The predicted optimum operating conditions are 75° inclination angle, 0.63 m2 absorber area, and 0.48-m chimney height. The maximum average exit air velocity and temperature numerically obtained are 0.64 m/s and 331 K, respectively, when operating with optimum conditions. It is observed that the exit air velocity increases 33% by increasing the absorber area from 0.5 to 3 m2 for a solar chimney with 0.5 m height. An increase in exit air velocity of 52% was obtained by increasing the chimney height from 0.5 to 3 m for a solar chimney with 0.64 m2 absorber area. A reduction in exit air velocity of 4% was observed for the increment in wind flow over the glass cover from 1.5 to 3 m/s. These results confirm that the solar chimney could be designed based on the predicted monthly performance by the present model.

Flat Plate Solar Collector Characteristic with Shutter Glass Distance Variation and Collector Inclination Angle

It has been done a research to determine the solar thermal collector efficiency of the flat plate collector. The testing of the collector was conducted on 30th November 2005, 1st, 3rd, 5th, 6th, 7th December 2005 with the variation of distance between one glass covers were varied from 3 cm, 6 cm, and 9 cm; and with inclination angle variation of collector from 10°, 20°, 30°, and 40°. Solar thermal collectors absorb the radiant energy from the sun and convert it to heat between the bottom glass cover and absorbing plates in the collector. Parameters which influence on the collector performance include distance between plate collector with glass covers and the inclination angle. It was found that the difference between output-input temperatures is the highest on a distance of 3 cm and inclination angle of 10°. This is influenced that inclination angle 10° more close to zenith angle. The solar thermal collector efficiency is not a constant; The solar collector efficiency depends on solar radiation intensity, input-output temperature difference and air flow. The smaller the inclination angle of solar collector, the higher the absorption radiation. If inclination angle of collector same with zenith angle, so the absorption radiation will maximum.

Investigation of salt contamination effects on the performance characteristics of the evacuated tubes solar water heater

The influence of salt layer contamination of thickness below (2 mm) on solar evacuated tubes water heater performance parameters was investigated experimentally in several operating weather conditions on October and November 2011 at Baghdad location taking into consideration the effect of ambient conditions and collector inclination angle. It was concluded that the salt thickness have a minor effect on the collector efficiency, water circulation in the tubes and the heat loss coefficient from the storage tank. While on the other hand, the collector angle and the ambient have a greater effect on the above-mentioned parameters.

Prediction and optimization of aerodynamic noise in an automotive air conditioning centrifugal fan

The high aerodynamic noise induced by automotive air conditioning systems has important effects on the ride comfort, and the centrifugal fan is the largest noise source in these systems. It is very important to reduce the aerodynamic noise generated by the centrifugal fan. The flow field and the sound field on the whole centrifugal fan configuration have been carried out using the computational fluid dynamics. Simulation results show that the sound pressure level near the outlet of the centrifugal fan is too high. Based on the relationship between flow characteristics and the aerodynamic noise, four parameters of the centrifugal fan, i.e., impeller blade’s outlet angle θ, volute tongue’s gap t, collector inclination angle β, and rotating speed n, were selected as design variables and optimized using response surface methodology. While keeping the function of flow rate unchanged, the peak noise level is reduced by 8 dB or 10.8%. The noise level is satisfactorily reduced.

Study on Application of Solar Heating System Integrated Latent Heat Store Heat Exchanger

This paper introduces the design of a solar heating system integrated latent heat store heat exchanger. Aiming at studying the system solar fraction, mathematical models are established for describing solar collector, latent heat store heat exchanger, users’ heating thermal load, and the system in whole. Studies are carried out based on these models. The results show that there are some key influencing factors on solar fraction, including solar irradiance, collector area, collector inclination angle, the difference value between collector inlet fluid temperature and ambient air temperature. Among these, collector inclination angle is the most significant one. If the values between collector inlet fluid temperature and ambient air temperature have big difference, it’ll cause adverse effects. As long as the operation requirements are met, lower collector inlet fluid temperature and suitable ambient air temperature are reasonable conditions for application. The research results provide guide for the system application in engineering.

Optimization of Economic Solar Field Design of Stationary Thermal Collectors

The optimization of solar field designs of stationary thermal collectors, taking into account shading and masking effects, may be based on energy or economic criteria. Obtaining maximum energy from a given field size or determining the required minimum field area that produces a given amount of energy are examples of energy criteria. Designing a solar plant with a minimum cost or a plant that produces minimum cost of unit energy are examples of economic criteria. These design problems may be formulated as optimization problems with objective functions and sets of constraints (equality and inequality) for which mathematical optimization techniques may be applied. This paper deals with obtaining optimal field and collector design parameters (number of rows, distance between collector rows, collector height, and collector inclination angle) that result in minimum periodic cost of a solar plant producing a given amount of annual energy. A second problem is the determination of optimal field and collector design parameters resulting in minimum cost of unit energy for the solar plant. In both cases, the optimal deployment of the collectors in the solar field as a function of the daily energy demand—cost of land and collector efficiency as parameters—is presented.

Optimal Solar Field Design of Stationary Collectors

The optimal design of stationary photovoltaic and thermal collectors in a solar field, taking into account shading and masking effects, may be based on several criteria: maximum incident energy on collector plane from a given field, minimum field area for given incident energy, minimum cost per unit energy, minimum plant cost, maximum energy per unit collector area or other objectives. These design problems may be formulated as optimization problems with objective functions and sets of constraints (equality and inequality) for which mathematical optimization techniques may be applied. This article deals with obtaining the field design parameters (optimal number of rows, distance between collector rows, collector height and collector inclination angle) that produce maximum annual energy from a given field. A second problem is determination of the minimum field area (length and width) and field design parameters that produce a given required annual energy. The third problem is determination of the optimal field design parameters for obtaining maximum energy per unit collector area from a given field. The results of these optimal designs are compared to a recommended approach of the Israeli Institute of Standards (IIS) in which the solar field design result in negligible shading. An increase in energy of about 20% for a fixed field area and a decrease in field area of about 15% for a given annual incident energy, respectively, may be obtained using the approach formulated in the present article compared to the IIS approach.

Performance studies of a solar once-through System (OTS) combined with a phase-change temperature-controlled valve (PCTCV)

An OTS is more convenient to use and provides better temperature-controlled water than a natural circulation system. An excellent way to control the exit-water temperature of an OTS is to utilize a PCTCV. Our results show how the average water temperature changes with insolation and collector inclination angle. The measured collector efficiency is close to 60%, while the overall efficiency for the system including the storage tank is relatively low due to poor thermal insulation and large heat capacity of the storage tank. Calculated results agree with experimental measurements.

Assessing the economic aspects of solar hot water production in Greece

The long-term performance of various systems was determined and the economic aspects of solar hot water production were investigated in this work. The effect of the collector inclination angle, collector area and storage volume was examined for all systems, and various climatic conditions and their payback period was calculated. It was found that the collector inclination angle does not have a significant effect on system performance. Large collector areas have a diminishing effect on the system's overall efficiency. The increase in storage volume has a detrimental effect for small daily load volumes, but a beneficial one when there is a large daily consumption. Solar energy was found to be truly competitive when the conventional fuel being substituted is electricity, and it should not replace diesel oil on pure economic grounds. Large daily load volumes and large collector areas are in general associated with shorter payback periods. Overall, the systems are oversized and are economically suitable for large daily hot water load volumes.