The Effect of Material Properties on the Thermal Efficiency of the Minto Solar Wheel

1980 ◽  
Vol 102 (2) ◽  
pp. 504-507 ◽  
Author(s):  
S. Lin ◽  
R. Bhardwaj
Keyword(s):  
Thermal Performance ◽  
Thermal Efficiency ◽  
Material Properties ◽  
Working Fluid ◽  
Working Fluids ◽  
Mean Diameter ◽  
The Mean ◽  
The Ideal

The characteristic of the thermal performance of the Minto solar wheel is that its thermal efficiency is strongly dependent on the material properties of the working fluid. For a specified working fluid, the thermal efficiency of the ideal cycle of the Minto solar wheel is dependent only on the mean diameter of the wheel. To study the effect of the material properties of the working fluid on the ideal thermal efficiency, 14 working fluids are selected, and their thermal efficiencies as functions of the mean diameter of the wheel are calculated and compared with each other. Among these fluids, R-12, R-115, R-500, R-22 and R-13B1 achieve better thermal performance than the others.

Experimental Study of Thermal Performance of Nanofluid-Filled and Nanoparticles-Coated Mesh Wick Heat Pipes

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Naveen Kumar Gupta ◽  
Arun Kumar Tiwari ◽  
Subrata Kumar Ghosh
Keyword(s):  
Thermal Resistance ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Physical Vapor Deposition ◽  
Power Input ◽  
Working Fluid ◽  
Physical Vapor Deposition Method ◽  
The Stability ◽  
Stability Issues ◽  
Time Of Operation

The enhancements in thermal performance of mesh wick heat pipe (HP) using TiO2/H2O nanofluid (0.5, 1.0, and 1.5 vol %) as working fluid for different (50, 100, and 150 W) power input were investigated. Results showed maximum 17.2% reduction in thermal resistance and maximum 13.4% enhancement in thermal efficiency of HP using 1.0 vol % nanofluid as compared to water. The wick surface of the HP was then coated with TiO2 nanoparticles by physical vapor deposition method. The experimental investigation had been also carried out on coated wick HP using water as working fluid. Results showed 12.1% reduction in thermal resistance and 11.9% enhancement in thermal efficiency of the HP as compared to uncoated wick HP using water. Temporal deteriorations in thermal performance during prolonged working (2, 4, and 6 months) of HP were also studied. Temporal deterioration in thermal performance of HP filled with nanofluid depends upon the deterioration in thermophysical properties of nanofluids. The deterioration is due to the agglomeration and sedimentation of nanoparticles with respect to the time. Comparative study shows that after a certain time of operation, thermal performance of HP with nanoparticle coated wick superseded that of the HP filled with nanofluid. Therefore, nanoparticle coating might be a good substitute for nanofluid to avoid the stability issues. The present paper provides incentives for further research to develop nanofluids that avoid the encountered sedimentation or agglomeration.

scholarly journals EFFICIENCY OF THE REGENERATIVE CYCLE OF BRIGHTON WITH VARIABLE THERMOPHYSICAL PROPERTIES OF THE WORKING FLUID (Part 2)

2018 ◽  
Vol 41 (3) ◽  
pp. 5-13
Author(s):  
A.A. Khalatov ◽  
S.D. Severin ◽  
O.S. Stupak ◽  
O.V. Shihabutinova
Keyword(s):  
Moisture Content ◽  
Thermophysical Properties ◽  
Thermal Efficiency ◽  
Second Law Of Thermodynamics ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Carnot Cycle ◽  
Regenerative Cycle ◽  
The Ideal

The data about thermodynamic efficiency of the ideal Brighton cycle with heat regeneration with constant thermophysical properties of the working fluid, as well as the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine (with variable thermophysical properties of the working fluid). The inapplicability of comparison of the thermal efficiency of the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine with the thermal efficiency of the equivalent ideal Carnot cycle is shown. The analysis of the thermodynamic efficiency of an ideal regenerative Brighton cycle with a decrease in the working body at the entrance to the turbine allows us to make the following conclusions: With the growth of the mass moisture content of the working fluid when entering the turbine, the thermal efficiency of the regenerative cycle increases, but decreases with an increase in the degree of increase in the pressure level in the cycle. High values ​​of the thermal efficiency of the cycle () can be achieved with relatively small values ​​of the degree of increase in the pressure in the cycle () and high (up to d = 0,5) values ​​of the mass moisture content of the working body when entering the turbine. It is shown that under certain conditions the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine may be greater than the thermal efficiency of a similar ideal Carnot cycle, which does not contradict the second law of thermodynamics, since the condition for the implementation of the Carnot cycle is the immutability of the thermophysical properties of the working body in a loop In this regard, the use of the expression for the thermal efficiency of the ideal Carnot cycle is not used as a criterion for assessing the efficiency of cycles of power plants with highly variable thermophysical properties of the working fluid. It is also shown that the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine is always lower than the thermal efficiency of the equivalent non-equilibrium Carnot cycle with a change in the specific heat of the working fluid, which corresponds to the second law of thermodynamics. It is shown that the Brighton regenerative cycle with a decrease in the working body before the turbine can be represented as a conditional cycle with a higher maximum temperature of the cycle, which, depending on the mass content of the moisture content of the working body, can in 1,2 ... 2,5 times exceed the actual maximum temperature cycle, which determines the high values ​​of its thermal efficiency.

Thermal performance optimization of a parabolic trough collector operating with various working fluids using copper nanoparticles.

2021 ◽  
pp. 1-35
Author(s):  
Yasser M. Abdullatif ◽  
Eric Chekwube Okonkwo ◽  
Tareq Al-Ansari
Keyword(s):  
Copper Nanoparticles ◽  
Thermal Performance ◽  
Performance Optimization ◽  
Volume Flow Rate ◽  
Liquid Sodium ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Parabolic Trough ◽  
Pressurized Water ◽  
Working Fluids

Abstract This study presents a thermal performance comparison of various working fluids in Parabolic Trough Collectors. Fluids such as gases (helium, carbon dioxide, and air), liquid sodium, and liquids (pressurized water, Therminol VP1, Syltherm 800) are evaluated. This study also examines the efficiency enhancement obtained from the dispersion of copper nanoparticles in water, Therminol-VP1, and Syltherm 800 base fluids. The optimum parameters for nanoparticle concentration, volume flow rate, and inlet temperature to obtain the maximum efficiencies for each working fluid were evaluated in this study. The thermal model used in this study was modelled after the commercially available LS-2 collector, which was designed in the engineering equation solver (EES) and validated with results found in literature. The results of the study show that the Cu/Syltherm 800 nanofluid showed the most enhancement in thermal efficiency with 0.62% while Cu/water and Cu/Therminol VP1 had enhancements of 0.3% and 0.2% respectively.

scholarly journals Augmentation of the Thermal Efficiency of PTC using CeO2 Nanofluid

2019 ◽  
Vol 9 (1) ◽  
pp. 6268-6272
Keyword(s):  
Thermal Analysis ◽  
Energy Efficiency ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Good Choice ◽  
Working Fluid ◽  
Synthetic Oil ◽  
Smooth Flow ◽  
Heating Water ◽  
Current Scenario

In the current scenario, experts largely focused on mi niaturizing devices and energy efficiency during the development of solar system.In the present study, nanofluid is used as a working fluid to see its effect on the thermal performance of PTC. The Thermal analysis of PTC heating water using CeO2 nanofluids as a working fluid is presented. The experimentation were carried out using cerium oxide nanofluid, water and synthetic oilThe result shows hat CeO2 nanofluid can be a good choice as a working fluid for smooth flow condition to use in PTC rather than water or any other synthetic oil. Experiment result shows, CeO2 - water can increase thermal efficiency by 2.66 times w.r.t water and 1.7 times w.r.t. synthetic oil.

scholarly journals Comparison between Organic Working Fluids in order to Improve Waste Heat Recovery from Internal Combustion Engines by means of Rankine Cycle Systems

2020 ◽  
Vol 71 (1) ◽  
pp. 113-121
Author(s):  
Alexandru Racovitza ◽  
Horatiu Pop ◽  
Valentin Apostol ◽  
Tudor Prisecaru ◽  
Daniel Taban
Keyword(s):  
Thermal Efficiency ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Internal Combustion Engines ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Internal Combustion ◽  
Working Fluid ◽  
Working Fluids ◽  
Cycle Systems

The present works deals with waste heat recovery from internal combustion engines using Rankine cycle systems where working fluid are organic liquids (ORC). The first part of the paper presents the ORC technology as one of the most suitable procedure for waste heat recovery from exhaust gas of internal combustion engine (ICE). The particular engine considered in the present work is a turbocharged compression ignition engine mounted on an experimental setup. The working fluids for ORC system are: isobutene, propane, RE245fa2, RE245cb2, R245fa, R236fa, R365mfc, R1233zd(E), R1234yf and R1234ze(Z). Experimental data derived from the experimental setup has been used for 40%, 55% and 70% engine load. This papers focusses on superheating increment, on thermal efficiency and on net power output, obtained with each working fluids in Rankine cycle. Results point out the superheating increment that gives the highest thermal efficiency for each working fluid. The highest thermal efficiency is achieved in case of using R1233zd(E) as working fluid. In case of using R1233zd(E) as working fluid at 40 % load of the engine, the output power of the Rankine cycle is 3.6 kW representing 6.2 %, from the rated power at this load; at 55% load it is 5.7 kW representing 6.7 % the rated power and at 70% it is 6.7 kW representing 6.5 % from the rated power. Future perspectives are given.

scholarly journals Effect of working fluids and internal diameters on thermal performance of vertical and horizontal closed-loop pulsating heat pipes with multiple heat sources

2016 ◽  
Vol 20 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Niti Kammuang-Lue ◽  
Phrut Sakulchangsatjatai ◽  
Pradit Terdtoon
Keyword(s):  
Thermal Performance ◽  
Closed Loop ◽  
Capillary Tube ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Internal Diameter ◽  
Heat Sources ◽  
Pulsating Heat Pipe ◽  
Working Fluids ◽  
Fundamental Information

Some electrical applications have a number of heat sources. The closed-loop pulsating heat pipe (CLPHP) is applied to transfer heat from these devices. Since the CLPHP primarily transfers heat by means of the working fluid?s phase change in a capillary tube, the thermal performance of the CLPHP significantly depends on the working fluid type and the tube?s internal diameter. In order to provide the fundamental information for manufacturers of heat exchangers, this study on the effect of working fluids and internal diameters has been conducted. Three electrical plate heaters were installed on the CLPHP as the heat sources. The experiments were conducted by varying the working fluid to be R123, ethanol, and water, and the internal diameter to be 1.0 mm, 1.5 mm, and 2.0 mm. For each set of the same working fluid and internal diameter, the input heat fluxes of the heat sources were also made to vary within six different patterns. It can be concluded that when the latent heat of evaporation increases - in the case of vertical CLPHP - and when the dynamic viscosity of the liquid increases - in the case of horizontal CLPHP - the thermal performance decreases. Moreover, when the internal diameter increases, the thermal performance increases for both of vertical and horizontal CLPHPs.

Thermal Performance of Steam Receiver in Tower-Type Solar Power Plants

2017 ◽  
Author(s):  
Kai Yan ◽  
Xiaojiang Wu ◽  
Jianbin Liu
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Solar Power ◽  
Working Fluid ◽  
Receiver Design ◽  
Solar Power Plants ◽  
Performance Calculation

In this paper, the thermal performance of steam receiver in tower-type solar power plants has been performed using the tower-type solar receiver design program developed by Shanghai boiler works Co Ltd. In the program, the integrated effect of three types of heat transfer, i.e. heat conduction, convection and radiation, in the process of heat transfer of receivers has been considered. With integrating the characteristics and the working conditions of receivers of both steam and molten salt, the developed program can be used to perform the thermal performance calculations for the receivers of both working fluids. The proposed program was validated through Solar Two project and the satisfactory results achieve. A steam receiver in a tower-type solar power plant with double superheats is selected as an example for thermal performance calculation. In view of the receiver operating in subcritical status, the thermal performance calculation is carried out for two sections, the one for evaporation and that for superheat. In evaporation section, the working fluid is circulated with a circulating pump at a very high circulating ratio. At the outlet of panels, the qualities of working fluid can reach to maximum about 0.35. Besides, the great difference of qualities of working fluid at the outlet of panels is observed. Even for some pipes of some panels, the working fluid at the outlet is in liquid phase. The distribution of metal temperature at fin end of panels in the evaporation region varies dramatically from place to place and reaches to over 520 °C. In superheat region, the temperature of the outer front crown of tubes is concerned. The highest front point temperature of pipe, which reaches to maximum over 660 °C, is in the middle region of the last parts of the primary superheat pass. The thermal efficiency distribution of the receiver, including the evaporation and the superheat regions, are also performed. The results show that the averaged efficiency is about 86%. Besides, the phenomenon of negative thermal efficiency happens in both two regions. That is because the solar incidence cannot compensate the natural heat loss due to incident radiation reflection, the pipe wall infrared radiation and convective heat loss.

Equivalent Model for Interlocked Carcass Under Axial Loads

2016 ◽  
Author(s):  
Rodrigo Provasi ◽  
Fernando Geremias Toni ◽  
Clóvis de Arruda Martins
Keyword(s):  
Material Properties ◽  
Element Model ◽  
Equivalent Model ◽  
Cylindrical Layer ◽  
Geometric Complexity ◽  
Axial Loads ◽  
Flexible Pipe ◽  
Material Parameters ◽  
Mean Diameter ◽  
The Mean

The modelling of flexible pipe interlocked carcasses is complicated when considering all the geometric complexity of their profile. A possible approach is to model them as cylindrical equivalent layers. To follow this path several alternatives can be considered in changing the geometrical and material properties. However, the thickness and the mean radius of those layers must not be changed to not interfere with the diameter of the other flexible pipe layers. In this paper, a model of an orthotropic cylindrical layer, with the same thickness and mean diameter of the original carcass layer is constructed and its material parameters are adjusted for axial loads using a finite element model of the real carcass profile.

Effect of the Working Fluid on Performance of the ORC and Combined Brayton/ORC Cycle

2017 ◽  
Author(s):  
Alireza Javanshir ◽  
Nenad Sarunac
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Working Fluid ◽  
Working Fluids ◽  
Power Cycles ◽  
Topping Cycle ◽  
Selection Of

This study focuses on the power cycles such as organic Rankine cycle (ORC) and combined regenerative Brayton/ORC. The selection of working fluids and power cycles is traditionally conducted by trial and error method and performing a large number of parametric calculations over a range of operating conditions. A methodology for selection of optimal working fluid based on the cycle operating conditions and thermophysical properties of the working fluids was developed in this study. Thermodynamic performance (thermal efficiency and net power output) of a simple subcritical and supercritical ORC was analyzed over a range of operating conditions for a number of working fluids to determine the effect of operating parameters on cycle performance and select the best working fluid. New expressions for thermal efficiency of a simple ORC are proposed. In case of a regenerative Brayton/ORC, the results show that CO2 is the best working fluid for the topping cycle. Depending on the exhaust temperature of the topping cycle, Isobutane, R11 and Ethanol are the preferred working fluids for the bottoming (ORC) cycle, resulting in highest efficiency of the combined cycle. Finally, a performance map is presented as guidance for selection of the best working fluid for specific cycle operating conditions.

scholarly journals Potential of Solar Collectors for Clean Thermal Energy Production in Smart Cities using Nanofluids: Experimental Assessment and Efficiency Improvement

2019 ◽  
Vol 9 (9) ◽  
pp. 1877 ◽  
Author(s):  
M. Sarafraz ◽  
Iskander Tlili ◽  
Mohammad Abdul Baseer ◽  
Mohammad Safaei
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Tilt Angle ◽  
Thermal Efficiency ◽  
Smart Cities ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Working Fluid ◽  
Solar Thermal Collector ◽  
Evacuated Tube

In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the collector, mass fraction of the nanoparticles, the solar irradiance, the tilt angle and the filling ratio values of the heat pipes on the thermal performance of the solar collector was investigated. It was found that with an increase in the flow rate of the working fluid within the system, the thermal efficiency of the system was improved. Additionally, the highest thermal performance and the highest temperature difference between the inlet and the outlet ports of the collector were achieved for the nanofluid at wt. % = 0.1. The best tilt angle and the filling ratio values of the collector were 30° and 60% and the maximum thermal efficiency of the collector was 91% for a nanofluid at wt. % = 0.1 and flow rate of 3 L/min.

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