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Design and characterization of the non-uniform solar flux distribution measurement system
摘要： It is important to accurately measure the solar flux distribution on the heated surface for the utilization of solar energy. To this end, in this paper a new measurement system was proposed to measure the solar flux distribution of the absorber tube surface by taking advantage of the end loss effect. The new measurement system does not disturb the collected lights path and influence the operation of the solar collector. The solar flux distribution at different angles can be measured with a few number of heat flux gage by rotating the proposed solar flux measurement system. Compared with existing measurement techniques, the proposed solar flux measurement system has distinct advantages such as simple structure, flexible and reliable operation and easy application. An experimental platform was designed and constructed, and the solar flux distributions on the outer surface of the absorber under different conditions are measured. The feasibility and effectiveness of the proposed measurement method are validated by comparing the experiment results and the numerical simulation results.
关键词： solar flux distribution,solar flux measurement system,parabolic trough solar collector,experimental investigation
更新于2025-09-23 15:23:52
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Analysis of optical and thermal factors’ effects on the transient performance of parabolic trough solar collectors
摘要： Solar resources are inherently unsteady and their energy density on the earth is low. Thereby, when the solar energy is converted into thermal energy through concentrating the sunlight, how to predict the transient performance of parabolic trough solar collectors under the operating conditions is necessary for the steady useful output and the efficient use of the energy. So this paper describes a mathematical model of the transient thermal behaviors of parabolic trough solar collectors. Then, to validate this transient model, its numerical results are compared with the experimental data. These data were collected from a utility-scale loop of parabolic trough solar collectors. The comparison between the model predictions and the experimental data shows a consistent and reasonable agreement. Furthermore, the primary interest of this study is to determine how the temperature distributions of the absorber, the glass envelope and the heat transfer fluid evolve from initial conditions with specified optical and thermal parameters. Thus, this model is used to carry out parametric studies to make analyses of essential impact factors on transient behaviors of parabolic trough solar collectors. These factors include the temperature of the heat transfer fluid at the inlet, the initial conditions, and the optical efficiency. Moreover, this model has the function of continuous adjustment of the flow rate to satisfy the requirement of the temperature of the heat transfer fluid at the outlet according to varying boundary conditions. Hence, another analysis is performed to investigate transient processes when the flow rate is continuously adjusted at various DNI ramp rates.
关键词： Concentrating solar power,Transient model,Parabolic trough solar collector,Solar heating and cooling
更新于2025-09-23 15:23:52
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Performance of a modified solar chimney power plant for power generation and vegetation
摘要： This paper develops a mathematical model to investigate the performance of a modified solar chimney power plant (MSCPP) for purposes of both power generation and vegetation. It then estimates the net added benefit. Results show that with the vegetation area enlarging, the MFR of the vapor increases, and more heat is used as the latent heat for water evaporation, leading to considerable reduction of the power. Condensation from the saturated air occurs only for very large vegetation area. On a cooler day, the plant produces less power and the condensation occurs for smaller vegetation area. Higher relative humidity of ambient air results in clear reduction of the MFR of the vapor evaporating from the vegetation area, and accordingly the great enhancement of the power. The benefit from agricultural products is larger than the benefit loss caused by the electricity loss, and the benefit of fresh water condensed from the saturated air is negligible. This leads to net added benefit for the MSCPP compared to the conventional plant. The net added benefit becomes greater with larger vegetation area. When the chimney is heightened from 1000 m to 1500 m, the power is enhanced greatly; however, the net added benefit becomes smaller.
关键词： Vegetation,Solar collector,Latent heat,Fresh water,Solar chimney,Power generation
更新于2025-09-23 15:23:52
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Performance Evaluation of Short Parabolic Trough Collectors Integrated with a Small-Scale Solar Power and Heating System
摘要： An investigation is presented on the performance of a small-scale solar power and heating system with short parabolic trough collectors (PTCs). The steady-state model of the short PTCs is evaluated with outside experiments. The model mainly contains the heat loss of the receiver, the peak optical efficiency and the incident angle factor consisting of incident angle modifier and end loss. It is found that the end loss effect is essential in this model when the length of the PTCs is less than 48 m, especially in the winter. The standard deviation of the steady-state model is 1.4%. Moreover, the potential energy efficiency ratio of the solar power and heating system is considerably larger than the coefficient of performance (COP) of general air-source heat pumps, and increases with the decrease of the condensation temperature. An overall system efficiency of 49% can be reached. Lastly, the existence of a water storage tank improves the flexibility of heating the building, and the volume of the water storage tank decreases with the increase of the heating water temperature.
关键词： practical operating characteristics,parabolic trough solar collector,thermal performance,testing method,small-scale
更新于2025-09-23 15:23:52
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Thermal performance analysis of a novel linear cavity receiver for parabolic trough solar collectors
摘要： The trough solar thermal power generation system is one of the most mature solar thermal power generation systems. A novel major arc-shaped linear cavity receiver with a lunate channel based on the black cavity effect principle for parabolic trough solar collectors is proposed in this work. The effects of the inclination angle, collecting temperature, surface emissivity and aperture width on the heat loss are thoroughly analyzed with a two-dimensional numerical model coupling natural convection with surface radiation. In addition, the thermal performance of the proposed linear cavity receiver is compared with that of the Solel’s UVAC series evacuated collector tube. The results show that: (1) The natural convection heat loss is significantly affected by the inclination angle, while the radiation heat loss is mainly affected by the surface emissivity and the collecting temperature. (2) The aperture width of the receiver has a great impact on the thermal performance. The larger the aperture width is, the greater the heat losses. However, the aperture width can also affect the optical performance and the manufacturing cost. The reasonable aperture width for this kind of linear cavity receiver is about 50–70 mm with consideration of all these factors. (3) The proposed linear cavity receiver demonstrates comparative or even better thermal performance as traditional evacuated collector tubes, especially in high temperature range. In general, the proposed linear cavity receiver has the comparative shape and size as the traditional evacuated collector tubes. More importantly, it has the advantages of raising the collecting temperature and reducing the production and maintenance costs. Therefore, it can be used to replace the evacuated collector tube which has poor performance due to long-term operation.
关键词： Cavity receiver,Parabolic trough solar collector,Surface radiation,Natural convection,Thermal performance,Linear receiver
更新于2025-09-23 15:23:52
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A dynamic model based on response factor method and seasonal performance analysis for integration of flat plate solar collector with building envelope
摘要： Integrating solar thermal collectors into building envelopes (e.g. walls or roofs) is very promising due to no need of additional site to place solar collectors. When a solar collector is integrated with a building, the working conditions for both the solar collector and the building envelope are changed. This paper proposed a new dynamic thermal model based on the response factor method. The new model combines the conventional analysis method for solar collectors with building envelopes, therefore it is easy to be understood and is more convenient to be realized by programming in a computer than state space model. The calculated results by the dynamic model agreed well with those calculated by the state space model and the measured experimental data, suggesting a satisfying validity of the model proposed. The seasonal performance of a solar wall (integrating of solar collectors and walls) in Beijing was studied by the new model. The results showed that: (1) In winter, the useful heat gain by the solar wall was always a little higher than the separate wall by about 6.7–8.8%, and the heat loss through solar wall is reduced by 90% or more, this is very favorable to reduce space heating load. (2) In summer, the useful heat gain of solar wall was higher than the separate collector by about 2.1–10.2%, the heat transferred through walls was less or higher than the separate wall depending on the inlet water temperature.
关键词： Dynamic model,Building heat transfer,Response factor method,Integration of solar collector with building,Useful heat gains
更新于2025-09-23 15:23:52
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - The Increase of the Effectiveness of the Autonomous System of Solar Energy Supply
摘要： For the effective heat supply of the consumers the solar energy is viewed with the aim of replacing the organic fuel the costs on which constantly increase. The analysis of the existing solar collectors as the basic element of the system of solar heat supply and its factors for the increase of the effectiveness of its usage is shown. The interconnection of constructive and regime parameters of solar collectors and the necessity of the regulating the regime of their work for the effectiveness of the system of solar heat supply as a whole are also shown. To achieve the formulated purpose the regulating of the scheme of the connection of solar collectors between them is offered and as the source of power supply the solar battery is suggested for providing the autonomy of the system of solar heat supply. The principle of the control of the scheme of the connecting of solar collectors and the description of the regime of work of the suggested device are examined. The block scheme of the algorithm of control for providing the given parameters of regulating is worked out and shown.
关键词： system of solar heat supply,parameters of solar collector,algorithm of control,scheme of the connection of the collectors,solar collector,solar battery,solar radiation
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Advanced Science and Engineering (ICOASE) - Duhok (2018.10.9-2018.10.11)] 2018 International Conference on Advanced Science and Engineering (ICOASE) - Manufacturing Procedure of a Hybrid Design of Solar Collector (Sterilization and Water Heating) By Solar and Electrical Energy
摘要： The purpose of the research is to design a hybrid solar collector, called (L1). This Collector operates by solar energy during daylight hours, which is approximately (12) hours, the work of the solar collector (L1) continues during night by using electrical power. Solar collector was tested during the period of December - 2017 to May – 2018.The results were excellent where it’s records high temperature during the period from March - May 2018. Temperature recorded more than 100 Co. The outlet water from the solar collector (L1) was sterilized due to the high heating degree of the water, it reached boiling degree. The design of (L1) is suitable for a lot of environment or weather conditions, because it depends on the collection of the solar radiation in a small surface area; in addition, it works in low electrical power. Tests for (L1) were conducted in Basra city, southern Iraq, on latitude 30.5oN and longitude 47.8oE. Manufacturing of this solar collector is very easy with low cost. It can be used it in houses, scientific and health institutions.
关键词： Hybrid,solar collector,sterilization,Water heating,Renewable energy,Solar energy
更新于2025-09-23 15:22:29
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The Potential of Solar Air Heating in the Turkish Industrial Sector
摘要： Transpired solar collector (TSC) systems are simple solutions for the preheating of ventilation air with solar energy. Their performance is a function of several environmental factors, so the climatic conditions of the location play an important role. In this paper, the effect of different climatic zones on the thermal performance of the TSC is investigated. To exclude other sources of influence, the same reference industrial building is examined in four Turkish locations (Antalya, Istanbul, Ankara and Sivas) representing different climatic conditions. RETScreen simulation is carried out for all four regions to obtain the drop of conventional heating requirement in case absorber azimuth of 0°, 45° and 90°. To illustrate the performance, temperature rise, heating energy savings and annual solar fraction are presented. Generally, it can be stated that a location with cold climate and high solar radiation at the same time benefits most from the use of a TSC system. A mathematical correlation has been found showing the solar fraction's dependence on solar radiation and heating degree days. Finally, simulation results have been compared to a set of measurement data from an industrial building's TSC system near Istanbul.
关键词： transpired solar collector,unglazed transpired collector,solar space heating,solar air heating system
更新于2025-09-23 15:21:01
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A fully planar solar pumped laser based on a luminescent solar collector
摘要： A solar-pumped laser (SPL) that converts sunlight directly into a coherent and intense laser beam generally requires a large concentrating lens and precise solar tracking, thereby limiting its potential utility. Here, we demonstrate a fully-planar SPL without a lens or solar tracking. A Nd3+-doped silica fiber is coiled into a cylindrical chamber filled with a sensitizer solution, which acts as a luminescent solar collector. The body of the chamber is highly reflective while the top window is a dichroic mirror that transmits incoming sunlight and traps the fluorescence emitted by the sensitizer. The laser-oscillation threshold was reached at a natural sunlight illumination of 60% on the top window. Calculations indicated that a solar-to-laser power-conversion efficiency could eventually reach 8%. Such an SPL has potential applications in long-term renewable-energy storage or decentralised power supplies for electric vehicles and Internet-of-Things devices.
关键词： luminescent solar collector,decentralised power supplies,renewable-energy storage,fully-planar,solar-pumped laser
更新于2025-09-23 15:21:01