scholarly journals Study of PTC System with Rectangular Cavity Receiver with Different Receiver Tube Shapes Using Oil, Water and Air

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2114
Author(s):  
Alireza Rafiei ◽  
Reyhaneh Loni ◽  
Gholamhassan Najafi ◽  
Talal Yusaf
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Energy Performance ◽  
Rectangular Cavity ◽  
Smooth Tube ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Solar Heat ◽  
Corrugated Tube ◽  
Thermal Oil

Today, application of cavity receivers in solar concentrator systems is suggested as an interesting and novelty research subject for increasing thermal performance. In this research, a parabolic trough concentrator (PTC) with a rectangular cavity receiver was energetically investigated. The cavity receiver was studied with smooth and corrugated tubes. Different solar heat transfer fluids were considered, including water, air, and thermal oil. The effect of different operational parameters, as well as structural parameters, was investigated. The results showed that the linear rectangular cavity receiver with corrugated tube showed higher amounts of the absorbed heat and energy performance compared to the smooth tube as the cavity tube. Thermal performance of the rectangular cavity was improved using the application of water as the solar heat transfer fluid, which was followed by thermal oil and, finally, air, as the solar heat transfer fluid. Finally, it could be recommended that the rectangular cavity receiver with smooth tube using air as the solar heat transfer fluid is more appropriate for coupling this system with a Bryton cycle, whereas the rectangular cavity receiver with the corrugated tube using water or oil as the solar heat transfer fluid is recommended for achieving higher outlet temperature of the heat transfer fluid.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

A 3-D Model Simulation of High Temperature Solar Cavity Receiver

2017 ◽  
Author(s):  
Huayi Feng ◽  
Yanping Zhang ◽  
Chongzhe Zou
Keyword(s):  
Heat Transfer ◽  
Radiation Intensity ◽  
Large Scale ◽  
Model Simulation ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Heat Transfer Efficiency ◽  
Direct Normal Irradiance

In this paper, a 3-D numerical model is proposed to investigate the capability of generating high operating temperature for a modified solar cavity receiver in large-scale dish Stirling system. The proposed model aims to evaluate the influence of radiation intensity on the cavity receiver performance. The properties of the heat transfer fluid in the pipe and heat transfer losses of the receiver are investigated by varying the direct normal irradiance from 400W/m2 to 1000W/m2. The temperature of heat transfer fluid, as well as the effect of radiation intensity on the heat transfer losses have been critically presented and discussed. The simulation results reveal that the heat transfer fluid temperature and thermal efficiency of the receiver are significantly influenced by different radiation flux. With the increase of radiation intensity, the efficiency of the receiver will firstly increase, then drops after reaching the highest point. The outlet working fluid temperature of the pipe will be increased consistently. The results of the simulations show that the designed cylindrical receiver used in dish Stirling system is capable to achieve the targeted outlet temperature and heat transfer efficiency, with an acceptable pressure drop.

Thermal Performance of Solar Tower Using Air as Heat Transfer Fluid under MENA Region Climate

2020 ◽  
Author(s):  
Sara EL Hassani ◽  
Hanane AIT Lahoussine Ouali ◽  
Benyounes Raillani ◽  
Mohammed Amine Moussaoui ◽  
Ahmed Mezrhab ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Transfer Fluid ◽  
Mena Region

scholarly journals Testing the performance of a prototype thermal energy storage tank working with organic phase change material for space heating application conditions

2019 ◽  
Vol 116 ◽  
pp. 00038 ◽  
Author(s):  
Maria K. Koukou ◽  
Michail Gr. Vrachopoulos ◽  
George Dogkas ◽  
Christos Pagkalos ◽  
Kostas Lymperis ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Finned Tube ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Change Material

A prototype Latent Heat Thermal Energy Storage (LHTES) unit has been designed, constructed, and experimentally analysed for its thermal storage performance under different operational conditions considering heating application and exploiting solar and geothermal energy. The system consists of a rectangular tank filled with Phase Change Material (PCM) and a finned tube staggered Heat Exchanger (HE) while water is used as Heat Transfer Fluid (HTF). Different HTF inlet temperatures and flow rates were tested to find out their effects on LHTES performance. Thermal quantities such as HTF outlet temperature, heat transfer rate, stored energy, were evaluated as a function of the conditions studied. Two commercial organic PCMs were tested A44 and A46. Results indicate that A44 is more efficient during the charging period, taking into account the two energy sources, solar and heat pump. During the discharging process, it exhibits higher storage capacity than A46. Concluding, the developed methodology can be applied to study different PCMs and building applications.

scholarly journals Modeling and Characteristic Analysis of a Solar Parabolic Trough System: Thermal Oil as the Heat Transfer Fluid

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Zhai Rongrong ◽  
Yang Yongping ◽  
Yan Qin ◽  
Zhu Yong
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Working Condition ◽  
Heat Transfer Fluid ◽  
System Dynamic Model ◽  
Parabolic Trough ◽  
Characteristic Analysis ◽  
Collector System ◽  
Typical Summer ◽  
Thermal Oil

The thermal oil is applied as the heat transfer fluid in a solar parabolic trough collector system. Firstly, the system dynamic model was established and validated by the real operating data in typical summer and spring days in references. Secondly, the alteration characteristics of different solar radiation, inlet water temperature and flow rate, and collectors’ area and length are analyzed and compared with the normal working condition. The model can be used for studying, system designing, and better understanding of the performance of parabolic trough systems.

Exergy Control for a Flat-Plate Collector/Rankine Cycle Solar Power System

1991 ◽  
Vol 113 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Giampaolo Manfrida ◽  
Shukuru J. M. Kawambwa
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Thermal Performance ◽  
Saturated Vapor ◽  
Rankine Cycle ◽  
Pressure Level ◽  
Heat Transfer Fluid ◽  
Second Law ◽  
Operating Pressure ◽  
Performance Study

A performance study is presented of a Rankine organic cycle powered by a low temperature solar collector. In this work a two-phase collector is considered where the heat transfer fluid is vaporized and its saturated vapor expands in a turbine according to a Rankine cycle. The collector system is divided into a boiling and a nonboiling (subcooled) part: The limit between the two depends upon the value of flow rate and radiation. A modified form of the Bliss equation is used to model the thermal performance of the collector in terms of thermal efficiency versus DTI [DTI= (Absorber average temperature-Ambient temperature)/ Solar Radiation]. The system is analyzed by second-law analysis, and it includes several exergy losses of different types (heat transfer, heat loss, etc.) which determine the overall exergy balance. Different working fluids are considered, and optimization to a certain extent is demonstrated from this point of view. In order to minimize irreversibilities and guarantee the most efficient conversion processes, the most important point is the right selection of the collector operating pressure level, which depends on the instantaneous value of radiation and ambient temperature (as well as on the collector thermal performance). The choice of the optimal pressure level is done by means of second-law arguments; the flow rates across the collector, the turbine, and the condenser are consequently determined. A simulation over a typical sunny day in Florence, Italy allows the calculation of the expected daily performance.

A General Model for Analyzing the Thermal Characteristics of a Class of Latent Heat Thermal Energy Storage Systems

1999 ◽  
Vol 121 (4) ◽  
pp. 185-193 ◽  
Author(s):  
Kang Yanbing ◽  
Zhang Yinping ◽  
Jiang Yi ◽  
Zhu Yingxin
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Performance ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
General Model ◽  
Thermal Characteristics ◽  
System Structure ◽  
Heat Transfer Fluid

The present study describes and classifies latent heat thermal energy storage (LHTES) systems according to their structural characteristics. A general model is developed for analyzing the thermal characteristics of the various typical LHTES systems to simulate thermal characteristics such as instantaneous heat transfer rate, instantaneous thermal storage capacity, etc. of the various typical LHTES systems. The model can calculate some important but difficult to measure system parameters for monitoring the charging or discharging processes of the systems. The model is verified using experimental data in the literature. Results from the model can be used to discuss the influence of the characteristic geometric parameters of LHTES units, the physical properties of the phase change material (PCM), the flow type and the velocity of heat transfer fluid (HTF) on the system thermal performance and to identify the key factors influencing the system thermal performance. The general model can be used to select and optimize the system structure and to simulate the thermal behavior of various typical LHTES systems.

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