scholarly journals High-Temperature Particle Flow Testing in Parallel Plates for Particle-to-Supercritical CO2 Heat Exchanger Applications

2020 ◽  
Author(s):  
Hendrik F. Laubscher ◽  
Kevin J. Albrecht ◽  
Clifford K. Ho
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Supercritical Co2 ◽  
Cost Effective ◽  
Particle Flow ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Parallel Plates ◽  
Design Work ◽  
Plate Spacing

Abstract Realizing cost-effective, dispatchable, renewable energy production using concentrated solar power (CSP) relies on reaching high process temperatures to increase the thermal-to-electrical efficiency. Ceramic based particles used as both the energy storage medium and heat transfer fluid is a promising approach to increasing the operating temperature of next generation CSP plants. The particle-to-supercritical CO2 (sCO2) heat exchanger is a critical component in the development of this technology for transferring thermal energy from the heated ceramic particles to the sCO2 working fluid of the power cycle. The leading design for the particle-to-sCO2 heat exchanger is a shell-and-plate configuration. Currently, design work is focused on optimizing the performance of the heat exchanger through reducing the plate spacing. However, the particle channel geometry is limited by uniformity and reliability of particle flow in narrow vertical channels. Results of high temperature experimental particle flow testing are presented in this paper.

Investigation of Supercritical CO2 Thermal Hydraulic Characteristics in a Printed Circuit Heat Exchanger

2018 ◽  
Author(s):  
Wen Fu ◽  
Xizhen Ma ◽  
Peiyue Li ◽  
Minghui Zhang ◽  
Sheng Li
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Supercritical Co2 ◽  
Three Dimensional ◽  
Working Fluid ◽  
Printed Circuit ◽  
Carbon Dioxide Co2

Printed circuit heat exchangers are considered for use as the intermediate heat exchangers (IHXs) in high temperature gas-cooled reactors (HTGRs), molten salts reactors (MSRs) and other advanced reactors. A printed circuit heat exchanger (PCHE) is a highly integrated plate-type compact heat exchanger with high-temperature, high-pressure applications and high compactness. A PCHE is built based on the technology of chemical etching and diffusion bonding. A PCHE with supercritical carbon dioxide (CO2) as the working fluid was designed in this study based on the theory correlations. Three-dimensional numerical analysis was then conducted to investigate the heat transfer and pressure drop characteristics of supercritical CO2 in the designed printed circuit heat exchanger using commercial CFD code, FLUENT. The distributions of temperature and velocity through the channel were modeled. The influences of Reynolds number on heat transfer and pressure drop were analyzed. The numerical results agree well with the theory calculations.

scholarly journals Influence of Parallel Plate Stack Spacing on the Temperature Difference of Thermoacoustic Refrigerator by using Helium as a Working Medium

2019 ◽  
Vol 8 (4) ◽  
pp. 2704-2712
Keyword(s):  
Heat Exchanger ◽  
Temperature Difference ◽  
Parallel Plate ◽  
Sheet Material ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Operating Pressure ◽  
Parallel Plates ◽  
Refrigeration System ◽  
Thermoacoustic Refrigerator

The refrigerants are usually provided in the conventional refrigeration system despite the fact that, they produce CFCs and HCFCs, which are hazardous to the environment. However, these disadvantages can be overcome using air or inert gas in the thermoacoustic refrigeration system. The present research involves the effect of spacing of parallel plate stack on the performance of thermoacoustic refrigerator (TAR) in terms of temperature difference (∆T). The entire resonator system as well as other structural parts of the refrigerator are fabricated by using PVC to reduce conduction heat loss. Three parallel plate stacks have been used to study the performance of TAR considering different porosity ratios by varying the gap between the parallel plates (0.28 mm, 0.33 mm and 0.38 mm). The parallel plate stacks are fabricated by using aluminium and mylar sheet material and the working fluid used for the experimental study is helium. The experiments have been carried out with different drive ratios ranging from 0.6% to 1.6% with operating frequencies of 200 – 600 Hz. Also the mean operating pressure used for the experiment is 2 to 10 bar and cooling load of 2 to 10W are considered. The ∆T between the hot heat exchanger and cold heat exchanger is recorded using RTDs and Bruel and Kjaer data acquisition system. Experimental results shows that the lowest temperature measured at cold heat exchanger is -2.1 oC by maintaining the hot heat exchanger temperature at about 32 oC. The maximum temperature difference of 32.90 oC is achieved.

scholarly journals The Influence of Stack Position and Acoustic Frequency on the Performance of Thermoacoustic Refrigerator with the Standing Wave

2017 ◽  
Vol 38 (4) ◽  
pp. 89-107 ◽  
Author(s):  
Jakub Kajurek ◽  
Artur Rusowicz ◽  
Andrzej Grzebielec
Keyword(s):  
Standing Wave ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Acoustic Power ◽  
Working Fluid ◽  
Parallel Plates ◽  
Acoustic Frequency ◽  
Plate Spacing ◽  
Resonance Frequencies ◽  
Thermoacoustic Refrigerator

Abstract Thermoacoustic refrigerator uses acoustic power to transport heat from a low-temperature source to a high-temperature source. The increasing interest in thermoacoustic technology is caused due to its simplicity, reliability as well as application of environmentally friendly working fluids. A typical thermoacoustic refrigerator consists of a resonator, a stack of parallel plates, two heat exchangers and a source of acoustic wave. The article presents the influence of the stack position in the resonance tube and the acoustic frequency on the performance of thermoacoustic refrigerator with a standing wave driven by a loudspeaker, which is measured in terms of the temperature difference between the stack edges. The results from experiments, conducted for the stack with the plate spacing 0.3 mm and the length 50 mm, acoustic frequencies varying between 100 and 400 Hz and air as a working fluid are consistent with the theory presented in this paper. The experiments confirmed that the temperature difference for the stack with determined plate spacing depends on the acoustic frequency and the stack position. The maximum values were achieved for resonance frequencies and the stack position between the pressure and velocity node.

scholarly journals Supercritical CO2 Heat Exchanger Fouling and its Impact on RCBC Efficiency

2018 ◽  
Author(s):  
Darryn Fleming ◽  
Kirsten Norman ◽  
Salvador Rodriguez ◽  
James Pasch ◽  
Matthew Carlson ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Supercritical Co2 ◽  
Critical Factor ◽  
Power Production ◽  
Working Fluid ◽  
Power Cycles ◽  
Power Cycle ◽  
Printed Circuit ◽  
Overall Efficiency

As supercritical carbon dioxide (sCO2) is emerging as a potential working fluid in power production Brayton cycles, fluid purity within the power cycle loops has become an issue impacting commercialization. Sandia National Laboratories has been evaluating the longevity of sCO2 recompression closed Brayton power cycles to quantify the advantages of sCO2 over other fluids as utilizing sCO2 yields comparatively greater efficiencies. Hydrocarbon plugging has been observed in the small printed circuit heat exchanger channels of our high temperature recuperator, increasing pressure drop across the heat exchanger. As pressure drop is a critical factor in the overall efficiency of sCO2 recompression closed Brayton cycles, in this paper we report on our investigation into heat exchanger efficiency reduction from hydrocarbon plugging induced pressure drop.

scholarly journals Thermal Behaviour Analysis of Baffled Multi Heat pipe Induced Heat Exchanger

2019 ◽  
Vol 8 (4S2) ◽  
pp. 275-279
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Thermal Behaviour ◽  
Cold Water ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Compact Heat Exchanger ◽  
Improve Performance ◽  
Flow Rates ◽  
Mass Flow Rates

Thermal behaviour of a multi-heat pipe induced in compact heat exchanger has been analysed with the influence of baffles. The heat transfer fluid and working fluid used for the investigation are water and acetone. In this investigation, baffles are used to improve performance. In this research, different parameters like temperature range of hot and cold water were 50ºC, 60ºC, 70ºC and 32ºC throughout the analysis. The mass flow rates of hot and cold water ranges as 40 LPH to 120 LPH and 20 LPH to 60 LPH with an increase of 20 LPH and 10 LPH. The result shows that for an optimum revealed conditions of an angle of 0º with 60ºC and 100 LPH there is an increase in effectiveness occurs as 82.05% while comparing to without baffled conditions.

Modeling of Supercritical Co2 Shell-and-Tube Heat Exchangers Under Extreme Conditions. Part 2: Heat Exchanger Model

2022 ◽  
Author(s):  
Akshay Bharadwaj Krishna ◽  
Kaiyuan Jin ◽  
Portnovo Ayyaswamy ◽  
Ivan Catton ◽  
Timothy S. Fisher
Keyword(s):  
Heat Exchanger ◽  
Numerical Model ◽  
Heat Exchangers ◽  
Supercritical Co2 ◽  
Critical Role ◽  
Computation Time ◽  
Efficient Estimation ◽  
Working Fluid ◽  
Computationally Efficient ◽  
Thermal Cycles

Abstract Heat exchangers play a critical role in supercritical CO2 Brayton cycles by providing necessary waste heat recovery. Supercritical CO2 thermal cycles potentially achieve higher energy density and thermal efficiency operating at elevated temperatures and pressures. Accurate and computationally efficient estimation of heat exchanger performance metrics at these conditions is important for the design and optimization of sCO2 systems and thermal cycles. In this paper (Part II), a computationally efficient and accurate numerical model is developed to predict the performance of STHXs. Highly accurate correlations reported in Part I of this study are utilized to improve the accuracy of performance predictions, and the concept of volume averaging is used to abstract the geometry and reduce computation time. The numerical model is validated by comparison with CFD simulations and provides high accuracy and significantly lower computation time compared to existing numerical models. A preliminary optimization study is conducted and the advantage of using supercritical CO2 as a working fluid for energy systems is demonstrated.

High-Temperature, Coal-Fired Combustor With Ceramic Heat Exchangers for CCGT Systems

1980 ◽  
Author(s):  
H. W. Carpenter ◽  
J. Campbell ◽  
L. H. Russell ◽  
D. E. Wright
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Heat Exchangers ◽  
Working Fluid

High-temperature, coal-fired combustors with ceramic heat exchangers were designed for CCGT systems. The objective in evaluating CCGT systems is to convert U.S. coal to electricity with higher efficiency. Higher temperatures are required to accomplish this goal and ceramic heat exchanger surfaces allow the use of working fluid temperatures to 2500 F and higher. The results of a comprehensive government study are described in which an atmospheric fluidized bed and cyclone fired combustor/heat exchanger were designed for operation at 1750 and 2250 F.

Numerical and Analytical Analyses of a High Temperature Heat Exchanger

2006 ◽  
Author(s):  
Donato Aquaro ◽  
Franco Donatini ◽  
Maurizio Pieve
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Analytical Model ◽  
Electric Utility ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Test Loop ◽  
Temperature Heat

In this paper some analytical and numeric analyses of a high temperature heat exchanger are performed. This heat exchanger should be employed in a test loop of a EFCC (Externally Fired Combined Cycle), placed in a experimental facility owned by the Italian electric utility, ENEL. The heat exchanger is the crucial element in this cycle, as it undergoes temperatures above 1000°C and pressures of about 7 bars. The enthalpy of the combustion products of low cost fuels, such as coal, bottom tar, residuals from refineries, is used to heat a clean working fluid, in this case pressurized air. There are some outstanding benefits for the turbine, in regard to the manufacturing and maintenance costs, and also for its life. The heat transfer components are some bayonet tubes, assembled in 4 modules. A half of them is made of ceramic materials, the others of an advanced metallic material (ODS), due to the burdensome operating conditions. First of all, the heat exchanges are evaluated by means of a simplified analytical model. The radiant contribution also has been taken into account, due to the presence of non-transparent gases. Subsequently, the in-tube fluid temperature increase is calculated for all the heat exchanger modules, through an enthalpy balance and with some simplifying assumptions. Moreover, a comparison is made between the analytical solution and the results of a numerical model implemented in a CFD code. A good agreement is found, which indicates that the analytical model is reasonably valid. In fact, the whole heat exchanger temperature change is determined by means of the two methods with a difference of about 7% for both the streams. Finally, these results are to be compared with the experimental data which should be available in the near future, when the facility will begin working. Also, by this way, the developed calculation model would get a validation.

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