- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A new TRNSYS type for thermosiphon flat-plate solar thermal collectors: validation and optimization procedure
摘要： This paper presents a new TRNSYS Type (called Type 99) which can be used for the energy assessment of thermosiphon Flat-Plate solar thermal Collectors (FPCs) for water heating. The accuracy of this new type is higher than the standard type (Type 45a) available in TRNSYS library, since the density and specific heat of water are estimated according to the operating fluid temperature. The results of a suitable experimental campaign are also presented for different commercial FPCs system layouts. The developed Type 99 is successfully validated, proven by the very good agreement achieved between the simulation and experimental results. By the new Type 99 a suitable Design of Experiment (DoE) analysis is carried out with the aim to assess the design and operating parameters mostly affecting the energy and economic performance of two types of FPCs. Specifically, collector pipe diameters, slope, storage tank volume, and thermal insulation thickness are investigated. The analysis is carried out for three case studies which refer to residential Domestic Hot Water (DHW) production applications and to three different European weather zones (Freiburg, Naples and Larnaca). For these case studies an optimization procedure is also carried out by varying the same design and operating parameters for two different objective functions: best energy behaviour [maximum Primary Energy Saving (PES)] and best economic performance [minimum Simple Pay Back (SPB)]. Interesting novel design criteria and encouraging economic results are obtained.
关键词： economic assessment,DoE analysis,Building solar thermal systems,dynamic energy performance analysis,experimental validation
更新于2025-09-23 15:22:29
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An analysis of low flow for solar thermal system for water heating
摘要： The mass flow rate in the collector loop of a solar domestic hot water system (SDHW) affects its thermal performance. The initial investment and the operation cost are also affected by the selection of the primary flow. Common design rules state a standard specific flow rate of 50 l/hm2 for most collector models. However, the emergence of electronically commuted motors recommends reviewing the interest of the low flow alternative (7–14 l/hm2) for solar thermal systems. In this paper, the thermal performance of a typical serpentine collector has been measured for different mass flow rates. The resulting performance curves and associated measurement uncertainty bands show only a moderate improvement in performance as the flow rate increases. Once the collector thermal behaviour has been characterized, the whole system is modelled, and the initial investment and operating cost are calculated for two design options: high flow (80 l/hm2) and low flow (20 l/hm2). As expected, the solar fraction is slightly higher for the high flow system (4.6% higher) and the number of hours of operation is lower for this system (4.4% less hours of operation). Considering the lower investment cost of the low flow system, the best thermal behaviour of the high flow system requires near 18 years to amortize the largest investment. If other considerations like embodied energy are accounted for, the common practice in designing SDHW systems should promote low flow.
关键词： Solar thermal simulation,Flat plate collector,Low flow,Variable flow
更新于2025-09-23 15:22:29
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A Novel Multi-objective Dynamic Programming Optimization Method: Performance Management of a Solar Thermal Power Plant as a Case Study
摘要： Due to the intermittent nature of solar irradiance, solar power plants are usually equipped with energy storage systems. Suitable charge and discharge management of the storage systems can considerably help increase the reliability and profitability of the solar systems. In this regard, various optimization approaches, with their own strengths and limitations, have been employed by literature. Dynamic Programming (DP) is one of the fittest approaches for the wide range of engineering problems which exhibit the properties of overlapping sub-problems. DP is a simple, gradient-free, efficient, and deterministic optimization method that guarantees the optimal solution. However, this method has not been developed for multi-objective problems. This study develops a multi-objective DP method and employs it for the performance management of a solar power plant equipped with thermal energy storage system. “Daily electricity generation” and “daily revenue obtained from selling electricity” are considered to be the objective functions. The superiority of the developed method is shown through a comparison with one of the most commonly used multi-objective optimization approaches, NSGA-II. This comparison indicates that the multi-objective DP attains 3.0%- 7.5% greater values of electricity generation and 3.1%-12.6% higher values of revenue than NSGA-II, for the different levels of solar radiation.
关键词： Thermal Energy Storage System,Optimal Performance,Solar Thermal Power Plant,Multi-objective Dynamic Programming method
更新于2025-09-23 15:21:21
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Supercritical Carbon Dioxide Solar Thermal Power Generation—Overview of the Technology and Microchannel Receiver Development
摘要： The supercritical carbon dioxide (sCO2) power cycle is being considered for solar thermal central receiver systems in the United States. The cycle lends to increased high-temperature input that is expected of the next-generation concentrating solar thermal power (CSP) systems. Power block efficiencies of about 50% can be achieved for recompression cycles at an input temperature of approximately 720 °C. Additionally, the power block is compact and less complex, raising the possibility of using thermal-storage-coupled CSP sCO2 technologies for modular (*100 MW) peak-load power plants. Three pathways toward providing solar thermal input to the sCO2 cycle have been proposed by various research groups—the molten salt receiver pathway, the solid particle receiver pathway, and the gas-phase receiver pathway. The first two technologies have the advantage of sensible thermal storage within the solid/fluid medium passing through the receiver. In the gas receiver pathway, there is a need for coupling a sensible or latent heat storage technology. Several key technologies are needed to enable the realization of the sCO2 solar thermal technology, key among them being the receiver and thermal storage. In this chapter, some of the key gas-phase receiver technologies are discussed. The group’s past and recent work on the development of microchannel solar thermal receivers for sCO2 is emphasized.
关键词： Solar thermal,Efficiency,Supercritical carbon dioxide,Microchannel,Receiver,Concentrating solar power
更新于2025-09-23 15:21:21
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Solar-driven interfacial evaporation
摘要： As a ubiquitous solar-thermal energy conversion process, solar-driven evaporation has attracted tremendous research attention owing to its high conversion efficiency of solar energy and transformative industrial potential. In recent years, solar-driven interfacial evaporation by localization of solar-thermal energy conversion to the air/liquid interface has been proposed as a promising alternative to conventional bulk heating-based evaporation, potentially reducing thermal losses and improving energy conversion efficiency. In this Review, we discuss the development of the key components for achieving high-performance evaporation, including solar absorbers, evaporation structures, thermal insulators and thermal concentrators, and discuss how they improve the performance of the solar-driven interfacial evaporation system. We describe the possibilities for applying this efficient solar-driven interfacial evaporation process for energy conversion applications. The exciting opportunities and challenges in both fundamental research and practical implementation of the solar-driven interfacial evaporation process are also discussed.
关键词： energy conversion,thermal insulators,thermal concentrators,solar absorbers,evaporation structures,interfacial evaporation,solar-driven evaporation,solar-thermal energy conversion
更新于2025-09-23 15:21:01
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Introduction to Advances in Solar Energy Research
摘要： A lot of activity has been taking place in the research community over the decades to efficiently harness solar energy. One way this is fuelled is by the support from the governments which promote the implementation of large-scale projects—whether it be for electric power generation (using PV), or for water heating using solar thermal collectors. These activities involve the efforts of the industry, which keep pace with the latest technology in the world, and are in a race to provide the most reliable technological solution to the customer for harnessing solar energy in an economical and robust manner. This has been the backdrop theme of almost all the chapters included in this book, which have been contributed by various authors from across the world. This is the first chapter of the book, and thus provides an overview of the various topics that will be covered in this book, ranging from an energy roadmap for the future, to technologies advances in the field of photovoltaics and solar cells (DSSC—Dye-Sensitized Solar Cells). It also includes details of solar thermal collector, along with the discussion about its heat transfer aspects. Apart from the two primary uses of solar energy—electric power generation and water heating—there are numerous applications for which it has been used over the years. Several such applications are also discussed in some of the subsequent chapters, such as refrigeration, desalination, gasification, and cooking.
关键词： Photovoltaics,Applications,Solar thermal systems,Solar energy,DSSC,Solar cells
更新于2025-09-23 15:21:01
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Advances in Concentrating Solar Thermal Research and Technology || Advanced control strategies to maximize ROI and the value of the concentrating solar thermal (CST) plant to the grid
摘要： There are two main drawbacks to concentrating solar thermal energy systems: (1) the resulting energy costs are not yet competitive and (2) solar energy is not always available when needed. Considerable research efforts are being devoted to techniques that may help to overcome these drawbacks; control is one of those techniques [1]. One of the main challenges identified by the US National Academy of Engineering is to make solar energy economical [2]. This issue can be addressed by reducing investment and operating costs and increasing the solar plant performance [3]. Advanced control techniques can help to reduce operating costs and increase the solar plant performance. This chapter describes two examples of how advanced control techniques can help to optimize operation of solar plants and, in consequence, maximize the return of investment (ROI).
关键词： advanced control strategies,solar tower plants,solar trough plants,concentrating solar thermal,ROI
更新于2025-09-23 15:21:01
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Experimental performance of an ultra-low-cost solar photovoltaic-thermal (PVT) collector using aluminum minichannels and nonimaging optics
摘要： Electricity, space heating, and hot water are ubiquitous needs among modern buildings. Solar photovoltaic/thermal (PVT) technologies are well suited to provide all of these in a distributed and renewable manner, however, the high cost of current PVT technologies remains a major barrier to implementation as the technology competes for roof space with low cost standalone PV modules. In an effort to reduce costs, a new type of solar PVT collector has been developed which replaces the traditional packaging materials with a low cost nonimaging optic and replaces sheet-and-tube heat exchange materials with a low cost and thermally efficient aluminum minichannel. A 1.2 m2 aperture prototype built using silicon SunPower solar cells has demonstrated 57.4% thermal efficiency and 12.3% electric efficiency at ambient temperature and a maximum (stagnation) temperature around 80 °C. Extrapolating this performance shows the PVT collector will to generate 226 kW-hours (kWh) of electricity and 603 kWh of heat per square meter each year for a solar resource of 5.5 kWh/m2/day, and by doing so avoid 1280 kWh of natural gas consumption and 183.8 kg of CO2 emissions. Technical performance is comparable with commercial PVT systems today, but with a much lower estimated module cost of $81/m2 ($0.54/WDC). A side-by-side analysis indicates the PVT collector can be installed for 85% of the capital cost of side-by-side PV + T with only 70% of the required roof space.
关键词： Hybrid,PVT,Solar,Thermal,Minichannel,Photovoltaic,Nonimaging
更新于2025-09-23 15:21:01
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Reduced Order Heat Exchanger Models for Low-to-Medium Temperature Range Solar Thermal Applications
摘要： Pivotal heat transfer components of solar thermal systems may involve single phase flow of the working fluid in some unit (e.g. single phase solar collector), whereas, two phase flow of the working fluid occurs in the other units (e.g. two-phase solar collector coupled directly to the turbine, boilers and evaporators). Modelling of these systems are important to understand the heat transfer behavior, as well as, to develop the system level control among many other attributes. A detailed analysis of single phase and two phase systems is possible using mathematical models to characterize the fluid flow and heat transfer. Detailed description of the fluid flow and heat transfer become computationally very expensive with such models, and also a very high level of precision may not be required in large time (*few hours) simulations of the systems, as well as, in controlling the entire solar thermal power plant. Hence there is a need to develop computationally fast, low order dynamic models. Among many other modelling approaches, a particular class of heat exchanger model, namely the moving boundary lumped-parameter model, has emerged as an efficient and effective tool for simulating dynamic characteristics of the two-phase solar collectors and the evaporators, pertinent to organic Rankine cycle (ORC) systems. These models are efficient in locating the continuously moving working fluid phase change boundary to the without requiring any sophisticated, well-trained formulation pertinent starting solutions. Even a simplified, reduced order quasi-steady state model is capable of demonstrating moving boundary characteristics in a narrow evaporator tube that is employed to carry organic refrigerant (working fluid) into the two-phase thermal applications in the medium temperature solar ORC heat exchanger (*200 °C). The model is capable of predicting the variation in working fluid mass transfer fluid (usually a flow rates with time-varying temperature of the heat
关键词： Reduced order modelling,Solar thermal system,Moving boundary model
更新于2025-09-23 15:21:01
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PERFORMANCE ENHANCEMENT OF CENTRALLY FINNED TWIST INSERTED SOLAR COLLECTOR USING CORRUGATED BOOSTER REFLECTORS
摘要： Performance enhancement of centrally finned twist (CFT) inserted solar collector using corrugated booster reflectors (CBR) have been approached experimentally. The experimental trials have been made with two different twist ratios (Y = 3 and 6) for typical twist (TT) and centrally finned twist (CFT) under same working conditions. The results were compared with the plain tube solar thermal collector (SC) with CBR and also with the plain tube SC with flat booster reflectors (FBR). The experimental result of the plain tube CBR SC has been verified with the standard equations and found the deviations within ±10.32% for Nusselt number and ±9.14% for friction factor. The CBR has 1.6% higher effective reflector area than the FBR. Hence, the CBR augmented the Nusselt number around 8.25% over the FBR. When compared to the plain tube CBR SC, the CFT of minimum twist ratio (Y = 3) offered 11.08% higher thermal efficiency. In addition, empirical correlations have been derived for predicting the Nusselt number and friction factor. The deviations of the predicted value from the experiment value fall within ±11.02% for Nusselt number and ±10.88% for friction factor.
关键词： Solar thermal collector,Corrugated booster reflectors,Flat booster reflectors,Typical twist,Centrally finned twist
更新于2025-09-23 15:21:01