Research on the Heat Transfer Characteristics of Receiver in Designed Solar Direct Steam Generation System

2014 ◽  
Vol 472 ◽  
pp. 286-290
Author(s):  
Jing Long Du ◽  
Xiang Huang ◽  
Da Wei Tang
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Stable Operation ◽  
Steam Generation ◽  
Generation System ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Direct Steam ◽  
Attractive Option ◽  
Simulation Results

The direct steam generation (DSG) with parabolic collector is an attractive option regarding the economic improvement of parabolic technology for solar thermal electricity generation system. On the basis of theory analysis of flow and heat transfer mechanism in the DSG system, this paper presents the numerical simulation results of one 650 meters loop under different direct normal irradiation values, performance parameters such as water temperature, heat transfer coefficient and dryness of the fluid in the absorber pipe are obtained in the simulation results. This paper shows that fluids parameters are susceptible to the solar direct normal values , high heat transfer efficiency and sensitive control system are the key to ensure DSG systems stable operation.

scholarly journals Enhanced Heat Transfer Characteristics of Graphite Concrete and Its Application in Energy Piles

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qingwen Li ◽  
Lu Chen ◽  
Haotian Ma ◽  
Chung-Ho Huang
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Transfer Efficiency ◽  
Heat Transfer Characteristics ◽  
Enhanced Heat Transfer ◽  
Energy Pile ◽  
Transfer Characteristics ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Energy Piles

The latest research on energy piles demonstrates that most scholars are focusing their attention on optimization by designing more efficient heat exchanger coils, analyzing the heat pump matching parameters, and so on. However, after more than 20 years of development, these traditional methods for improving the heat transfer efficiency of energy piles have reached a bottleneck, and a new approach for the continued enhancement of this technology must be investigated. In this study, powdered graphite with high heat transfer characteristics was included in a concrete mix to create graphite concrete piles with enhanced heat transfer characteristics. The results from theoretical analysis, laboratory testing, and numerical simulation indicate that using graphite to improve the heat transfer efficiency of a concrete material is an effective method for enhancing the thermal efficiency of an energy pile system. The research results also show that the heat transfer coefficient of the concrete exhibits greater improvement when the graphite content is greater than 15% under the same environmental temperature. After studying the performance of the proposed graphite concrete energy pile under different environmental temperatures (10°C, 20°C, 30°C, and 40°C), the results indicate that the working efficiency of the energy pile is better in the summer than in the winter. Finally, parameters such as the cast-in pipe configuration and pile spacing are optimized.

Decreasing the Fouling of Heat Exchanger Plates Using Air Bubbles

2010 ◽  
Vol 297-301 ◽  
pp. 1199-1204 ◽  
Author(s):  
Seung Moon Baek ◽  
Won Sil Seol ◽  
Ho Saeng Lee ◽  
Jung In Yoon
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Environmental Pollution ◽  
High Heat ◽  
Air Bubbles ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Heat Exchanger Plate ◽  
Removal Equipment ◽  
Exchanger Plate

The heat transfer performance of heat exchanger plate decreases as time goes by. The main reason for this phenomenon is the fouling of the heat exchanger plates. To remove the fouling, we have usually cleaned the plate of heat exchanger using chemicals or polishing brush or cloth with hand after stopping the equipment and disassembling the heat exchanger. However, to clean the plate using these methods, the heat exchanger equipment needs to be stopped and disjointed. In addition, it must be re-jointed after cleaning. Especially, the concern of environmental pollution happens in case of using chemicals. Therefore, we need to develop an automatic fouling removal equipment which can continuously keep high heat transfer efficiency and solve the problem of environmental pollution. So, in this paper, we developed and tested the equipment which can clean the fouling on heat exchanger plates automatically per constant period and interval using air bubbles. The total heat transfer coefficient decreased with a slower tendency when using air bubbles compared to the existing methods. There was 10% higher heat transfer effect air bubbles every 10 minutes for 2 hours to remove the fouling ingredients on the heat transfer surface area concerned to the case without air bubbles after 192 hours.

scholarly journals Heat Transfer and Bearing Characteristics of Energy Piles: Review

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6483
Author(s):  
Jinli Xie ◽  
Yinghong Qin
Keyword(s):  
Heat Transfer ◽  
Low Cost ◽  
High Heat ◽  
Heat Pumps ◽  
Transfer Efficiency ◽  
Ground Source Heat Pumps ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Energy Piles ◽  
Composite Energy

Energy piles, combined ground source heat pumps (GSHP) with the traditional pile foundation, have the advantages of high heat transfer efficiency, less space occupation and low cost. This paper summarizes the latest research on the heat transfer and bearing capacity of energy piles. It is found that S-shaped tubes have the largest heat transfer area and the best heat transfer efficiency; that energy piles need to be designed conservatively, such as adjusting the safety coefficient, number and spacing of the piles according to the additional temperature loads; and that unbalanced surface temperature has not been resolved, caused by uneven refrigeration/heating demand in one cycle. A composite energy pile applied to water-rich areas is proposed to overcome the decay of bearing and heat transfer performance. Besides, most of the heat transfer models are borehole-oriented and will fit for energy piles effectively if the models support variable ground temperature boundary conditions.

Research on Trait in Heat Exchange and Flow of Inner Single-Phase Currentin Micro Channel

2012 ◽  
Vol 516-517 ◽  
pp. 408-413 ◽  
Author(s):  
Yue Lian Hu
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Single Phase ◽  
Fluid Dynamic ◽  
High Heat ◽  
Micro Channel ◽  
Heat Transfer Efficiency ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
Phase Water

During recent years,micro-channel heat transfer technique has been successfully used in many practical situations，and has notable advantages of high heat transfer efficiency and compact configuration.It is an important subject in modern hydrodynamic and heat transfer research field.Computational fluid dynamic program CFX will be used in this article to simulate flow and heat transfer of single-phase water in micro-channel ,flow and temperature felid will be described visually in CFX, and this object is searching a new method to research more flow and heat transfer of single-phase water.

The Characteristics Research of Spray Evaporative Condenser

2012 ◽  
Vol 424-425 ◽  
pp. 1032-1036
Author(s):  
Zhong Hua Tang ◽  
Mo You Xiong ◽  
De Bao Lei
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Cooling Capacity ◽  
Working Pressure ◽  
Advantages And Disadvantages ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Different Types ◽  
Enthalpy Difference ◽  
Equipment Corrosion

Through theoretical analysis and experiment, this paper works for studying the heat transfer effect of different types condensers, combined with the advantages and disadvantages of different types of condensers, searching for the condenser which has high heat transfer efficiency and saves energy and water. Based on the experiment, we found that air through the water spray could significantly drop the air enthalpy, and increase the air enthalpy difference when it goes through the condenser. The atomization air could lessen air flow under the condition that the cooling capacity does not change, and that the compressor working pressure and fan power also would be reduced. This evaporative condensers compare with others saves much more water, reduces the coil fouling and equipment corrosion, and can improve the work reliability of the condenser

Heat Transfer Enhancement of Double-Tube-Type Heat Exchanger by Petal-Shaped Tube (Study on Optimum Tube Shape)

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Toshihiko Shakouchi ◽  
Yusuke Matsumoto ◽  
Koichi Tsujimoto ◽  
Toshitake Ando
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
High Heat ◽  
Practical Applications ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Tube Shape ◽  
Tube Type ◽  
Wetted Perimeter ◽  
Fin Tube

Abstract Heat exchangers are used widely in many fields, and various kinds of exchanger have been developed according to the requirement of the practical applications. Recently, heat exchangers that are highly efficient or compact have become more desirable from the viewpoint of energy conservation, and several new types have been developed, such as a compact fin tube type and a double tube type having an inner pipe with a special geometry. In this study, the flow and heat transfer characteristics of a petal-shaped double tube with a large wetted perimeter of six and five petals and five shallow petals and the effect of tube shape on the heat transfer and heat transfer efficiency were examined experimentally. The heat transfer of the double tube with a petal-shaped inner tube was increased because of the large wetted perimeter, but the pressure loss by friction increased. The optimal shape of the petal-shaped double tube with a high heat transfer performance and the greatest efficiency is discussed.

scholarly journals Heat Transfer Enhancement of Circular- and Petal- Shaped Double-Tube-Type Heat Exchangers by Triple Ones

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6590
Author(s):  
Toshihiko Shakouchi ◽  
Kazuma Yamamura ◽  
Koichi Tsujimoto ◽  
Toshitake Ando
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Cold Water ◽  
High Heat ◽  
Hot Water ◽  
Compact Heat Exchangers ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Tube Type ◽  
Counter Current

Conventional circular double or triple tube type heat exchanger, DHE or THE, is one of the compact heat exchangers; a large number of studies have been performed to improve their heat transfer performance. The authors demonstrated that a petal-shaped special DHE with a large wet perimeter yields a high heat transfer efficiency, η. In this study, the DHE with six or five petals-, five shallow petals-, and circular-inner tubes were used. To further improve the η of the DHE, a THE with a petal-shaped inner tube along with the middle and outer circular tubes were used. Hot water flowed through the inner tube and cold water flowed through the middle and outer tubes as a counter current flow. The heat transfer was approximately equal; however, the flow resistance (pressure loss) of the outer tube of the DHE could be decreased using the middle and outer tubes under the same amount of cold water as the DHE; consequently, the η could be improved. In addition, the effect of changing the flow path of the hot- and cold-water flows on the η was examined.

Numerical Study on Heat Transfer Enhanced in a Microcombustor With Staggered Cylindrical Array for Micro-Thermophotovoltaic System

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Haojie Li ◽  
Yanrong Chen ◽  
Yunfei Yan ◽  
Cheng Hu ◽  
Hu Fan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Equivalence Ratio ◽  
Numerical Study ◽  
High Heat ◽  
Stable Combustion ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Study Results ◽  
Ratio Range ◽  
Cylindrical Array

In consideration of high heat transfer efficiency and stable combustion, a new type of microplanar combustor for micro-thermophotovoltaic (micro-TPV) system is proposed, in which the heat transfer is enhanced by staggered cylindrical array. The numerical study results indicate that the temperature of radiation wall of cylindrical-array combustor is higher and more uniform comparing with the conventional-channel combustor, the application of cylindrical-array make the effective radiation of the combustor increase 34.55% and reach to 35.98 W. Moreover, with inlet velocity increase from 4 m/s to 16 m/s, the cylindrical-array combustor shows the better stability of combustion, which the position of the flame moves 4.8 mm in the cylindrical-array combustor and 9.1 mm in the conventional-channel combustor. However, the 0.5–4.5 equivalence ratio range for stable combustion is slightly narrower than 0.4–6.0 in the conventional-channel combustor. To extend the equivalence ratio range, one row of cylindrical array was canceled, and the distribution length of cylindrical array was reduced to 10 mm, After this improvement, the equivalence ratio range is extended to 0.3–5.5, and the negative effect on the flame stability of the cylindrical array is basically eliminated.

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