scholarly journals Modification of a Solar Thermal Collector to Promote Heat Transfer inside an Evacuated Tube Solar Thermal Absorber

2021 ◽  
Vol 11 (9) ◽  
pp. 4100
Author(s):  
Rasa Supankanok ◽  
Sukanpirom Sriwong ◽  
Phisan Ponpo ◽  
Wei Wu ◽  
Walairat Chandra-ambhorn ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Medium Temperature ◽  
Change Behavior ◽  
Set Up ◽  
Evacuated Tube ◽  
Heating Medium

Evacuated-tube solar collector (ETSC) is developed to achieve high heating medium temperature. Heat transfer fluid contained inside a copper heat pipe directly affects the heating medium temperature. A 10 mol% of ethylene-glycol in water is the heat transfer fluid in this system. The purpose of this study is to modify inner structure of the evacuated tube for promoting heat transfer through aluminum fin to the copper heat pipe by inserting stainless-steel scrubbers in the evacuated tube to increase heat conduction surface area. The experiment is set up to measure the temperature of heat transfer fluid at a heat pipe tip which is a heat exchange area between heat transfer fluid and heating medium. The vapor/ liquid equilibrium (VLE) theory is applied to investigate phase change behavior of the heat transfer fluid. Mathematical model validated with 6 experimental results is set up to investigate the performance of ETSC system and evaluate the feasibility of applying the modified ETSC in small-scale industries. The results indicate that the average temperature of heat transfer fluid in a modified tube increased to 160.32 °C which is higher than a standard tube by approximately 22 °C leading to the increase in its efficiency by 34.96%.

scholarly journals Experimental Investigation of a Medium Temperature Single-Phase Thermosyphon in an Evacuated Tube Receiver Coupled With Compound Parabolic Concentrator

2021 ◽  
Vol 9 ◽  
Author(s):  
Javed Akhter ◽  
S. I. Gilani ◽  
Hussain H. Al-Kayiem ◽  
Mubbashar Mehmood ◽  
Muzaffar Ali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Energy ◽  
Single Phase ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Solar Thermal Energy ◽  
Medium Temperature ◽  
Temperature Range ◽  
Evacuated Tube

The integration of evacuated tube receivers with non-imaging compound parabolic concentrators (CPCs) operating in thermosyphon mode provides the opportunity to deliver solar thermal energy in the medium temperature range that is suitable for many industrial applications. However, the performance of single-phase thermosyphon in the medium temperature range has not been comprehensively investigated. This paper presents the design, development, and performance evaluation of a single-phase thermosyphon in an evacuated tube receiver integrated with a modified CPC solar collector. The thermohydraulic performance of the developed system is evaluated in the tropical climate using Therminol-55 oil as heat transfer fluid. The results demonstrate that the maximum outlet temperature reached over 120°C using thermal oil as heat transfer fluid while it remained at 100°C in case of water. The zero-loss thermal efficiency reached up to 70% on a clear sky day. Comparing the thermal performance of the developed CPC collector with an existing model of a non-concentrating collector showed much improvement at elevated temperatures. This indicates that this system can effectively operate in tropical weather conditions to provide sustainable solar thermal energy in the medium temperature range.

Review of Materials and Environment Management for Solar Thermal Collectors

2014 ◽  
Vol 521 ◽  
pp. 539-542
Author(s):  
Da Yu Zheng ◽  
Juan Zheng ◽  
Xiang Yi Guan ◽  
Jia Zheng ◽  
Yi Ming Zhang
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pipe ◽  
Research Work ◽  
Solar Thermal ◽  
Senior Managers ◽  
Solar Thermal Collectors ◽  
Evacuated Tubes ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges. A range of published papers and internet research including research work on various solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube) were used. Evaluation of solar collectors performance is critiqued to aid solar technologies make the transition into a specific dominant solar collector. The sources are sorted into sections: finding an academic job, general advice, teaching, research and publishing, tenure and organizations. Provides information about types of solar thermal collectors, indicating what can be added by using evacuated tube collectors instead of flat plate collectors and what can be added by using heat pipe collectors instead of evacuated tubes. Focusing only on three types of solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube). Useful source of information for consultancy and impartial advice for graduate students planning to do research in solar thermal technologies. This paper fulfils identified information about materials and heat transfer properties of materials and manufacturing challenges of these three solar thermal collectors. Describes some changes made to improve the environment which have had unforeseen and adverse effects on safety and the reasons why we need more case histories. Also discusses the reasons why there are no permanent solutions to safety problems and the reasons why senior managers should become more involved in safety problems.

Thermal Performance Analysis of a Novel U-Tube Evacuated Tube Solar Collector

2020 ◽  
Author(s):  
Celine S. L. Lim ◽  
Vivek R. Pawar ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Solar Collector ◽  
Performance Comparison ◽  
Heat Transfer Fluid ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Evacuated Tube Solar Collector ◽  
Evacuated Tube

Abstract Solar water heating (SWH) systems are the most common application of renewable energy technology that converts solar radiation into useful energy for domestic/industrial activities. The novelty of this study is the design of a new SWH that combines the heat transfer and storage both in a single unit. The selected type of collector for this purpose is an evacuated tube solar collector (ETC). The new design of the ETC has been developed by applying a U-tube inside the collector which contains the heat transfer fluid (HTF). The HTF flows into an external heat exchanger that transfers heat to the water. The implementation of sugar alcohol namely Erythritol (C4H10O4) as the HTF for moderate operating temperature applications was investigated. Moreover, the utilization of solid-liquid phase change material, Tritriacontane paraffin (C33H68), inside the ETC, allows direct heat storage on the system and delayed release of heat. A computational fluid dynamics (CFD) modeling of a single U-tube ETC is performed using ANSYS Fluent in stagnation (on-demand) operation. A 3D model of the ETC is developed and the appropriate boundary conditions are applied. Moreover, the thermal performance comparison of U-tube vs heat pipe ETC has been done. The results from this study shows the maximum fin temperature difference of 46°C of U-tube ETC compared with heat pipe ETC.

Review of Materials for Solar Thermal Collectors

2010 ◽  
Vol 171-172 ◽  
pp. 486-489
Author(s):  
Jie Li
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pipe ◽  
Research Work ◽  
Solar Thermal ◽  
Solar Thermal Collectors ◽  
Evacuated Tubes ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube ◽  
Transfer Properties

To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges. A range of published papers and internet research including research work on various solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube) were used. Evaluation of solar collectors performance is critiqued to aid solar technologies make the transition into a specific dominant solar collector. The sources are sorted into sections: finding an academic job, general advice, teaching, research and publishing, tenure and organizations. Provides information about types of solar thermal collectors, indicating what can be added by using evacuated tube collectors instead of flat plate collectors and what can be added by using heat pipe collectors instead of evacuated tubes. Focusing only on three types of solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube). Useful source of information for consultancy and impartial advice for graduate students planning to do research in solar thermal technologies. This paper fulfils identified information about materials and heat transfer properties of materials and manufacturing challenges of these three solar thermal collectors.

scholarly journals Comparison of Li2CO3-Na2CO3-K2CO3, KCl-MgCl2 and NaNO3-KNO3 as heat transfer fluid for different sCO2 and steam power cycles in CSP tower plant under different DNI conditions

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110119
Author(s):  
Kamran Mahboob ◽  
Awais A Khan ◽  
Muhammad Adeel Khan ◽  
Jawad Sarwar ◽  
Tauseef A Khan
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Rankine Cycle ◽  
Capacity Factor ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Incident Power ◽  
Steam Power ◽  
Power Cycles ◽  
Plant Configuration

This work presents the characteristics of a solar thermal tower power plant in two different places (Seville and Dubai) using three different HTFs (NaNO3-KNO3, KCl-MgCl2 and Li2CO3-Na2CO3-K2CO3) and three different power cycles (Rankine, sCO2 Recompression and sCO2 Partial cooling cycles). An indirect configuration is considered for the Gemasolar power plant. Detailed modelling is carried out for the conversion of incident power on the heliostat to the output electricity. Optimization of the cycle is carried out to determine the most promising cycle configuration for efficiency. The results showed that for the Gemasolar power plant configuration, the performance of the KCl-MgCl2 based plant was poorest amongst all. NaNO3-KNO3 based plant has shown good performance with the Rankine cycle but plant having Li2CO3-Na2CO3-K2CO3 as HTF was best for all three cycles. Partial cooling was the best performing cycle at both locations with all three HTFs. Placing the Seville Plant in Dubai has improved the efficiency from 23.56% to 24.33%, a capacity factor improvement of 21 and 52 GW additional power is generated. The optimization of the plant in Dubai has shown further improvements. The efficiency is improved, the Capacity factor is increased by 31.2 and 77.8 GW of additional electricity is produced.

Central Receiver System Solar Power Plant Using Molten Salt as Heat Transfer Fluid

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
J. Ignacio Ortega ◽  
J. Ignacio Burgaleta ◽  
Félix M. Téllez
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Molten Salt ◽  
Thermal Power ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Solar Thermal Power ◽  
Central Receiver ◽  
Spanish Legislation ◽  
Solar Thermal Power Generation

Of all the technologies being developed for solar thermal power generation, central receiver systems (CRSs) are able to work at the highest temperatures and to achieve higher efficiencies in electricity production. The combination of this concept and the choice of molten salts as the heat transfer fluid, in both the receiver and heat storage, enables solar collection to be decoupled from electricity generation better than water∕steam systems, yielding high capacity factors with solar-only or low hybridization ratios. These advantages, along with the benefits of Spanish legislation on solar energy, moved SENER to promote the 17MWe Solar TRES plant. It will be the first commercial CRS plant with molten-salt storage and will help consolidate this technology for future higher-capacity plants. This paper describes the basic concept developed in this demonstration project, reviewing the experience accumulated in the previous Solar TWO project, and present design innovations, as a consequence of the development work performed by SENER and CIEMAT and of the technical conditions imposed by Spanish legislation on solar thermal power generation.

Real Time Experimental Performance Assessment of a Photovoltaic Thermal System Cascaded with Flat Plate and Heat Pipe Evacuated Tube Collector

2021 ◽  
pp. 1-28
Author(s):  
Laveet Kumar ◽  
Md Hasanuzzaman ◽  
Nasrudin Abd Rahim
Keyword(s):  
Performance Assessment ◽  
Flat Plate ◽  
Heat Pipe ◽  
Large Scale ◽  
Industrial Process ◽  
Simulation Models ◽  
Solar Thermal ◽  
Evacuated Tube Collector ◽  
Flat Plate Collector ◽  
Evacuated Tube

Abstract In response to the global quest for a sustainable and environmentally friendly source of energy most scientists' discretion is solar energy, especially solar thermal. However, successful deployment of solar thermal technologies such as solar assisted process heating (SAPH) systems in medium- to large-scale industries is still in quandary due to their inefficacy in raising ample temperatures. Cascaded SAPH system, which is essentially a series combination of two same or different types of thermal collectors, may provide a worthwhile solution to this problem. In this article, performance assessment and comparison of two cascaded SAPH systems have been presented: photovoltaic thermal (PVT) cascaded with flat-plate collector (PVT-FPC) and PVT coupled with heat-pipe evacuated tube collector (PVT-HPETC). Simulation models have been presented for individual FPC, HPETC and PVT as well as PVT cascaded with FPC and HPETC systems in TRNSYS and validated through outdoor experimentation. Both the first and the second laws of thermodynamics have been employed to reveal veritable performance of the systems. Results show that PVT-HPETC delivers better performance with 1625 W thermal energy, 81% energy efficiency and 13.22% exergy efficiency. It cuts 1.37 kg of CO2 on an hourly basis. Cascaded systems can be effective in sustaining industrial process heat requirements.

scholarly journals Performance Evaluation of a Small-Scale Latent Heat Thermal Energy Storage Unit for Heating Applications Based on a Nanocomposite Organic PCM

2019 ◽  
Vol 3 (4) ◽  
pp. 88 ◽  
Author(s):  
Maria K. Koukou ◽  
George Dogkas ◽  
Michail Gr. Vrachopoulos ◽  
John Konstantaras ◽  
Christos Pagkalos ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Behavior ◽  
Latent Heat ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Transfer Fluid ◽  
Small Scale ◽  
Solidification Processes

A small-scale latent heat thermal energy storage (LHTES) unit for heating applications was studied experimentally using an organic phase change material (PCM). The unit comprised of a tank filled with the PCM, a staggered heat exchanger (HE) for transferring heat from and to the PCM, and a water pump to circulate water as a heat transfer fluid (HTF). The performance of the unit using the commercial organic paraffin A44 was studied in order to understand the thermal behavior of the system and the main parameters that influence heat transfer during the PCM melting and solidification processes. The latter will assist the design of a large-scale unit. The effect of flow rate was studied given that it significantly affects charging (melting) and discharging (solidification) processes. In addition, as organic PCMs have low thermal conductivity, the possible improvement of the PCM’s thermal behavior by means of nanoparticle addition was investigated. The obtained results were promising and showed that the use of graphite-based nanoplatelets improves the PCM thermal behavior. Charging was clearly faster and more efficient, while with the appropriate tuning of the HTF flow rate, an efficient discharging was accomplished.

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