Pyrometric Temperature Measurements in Solar Furnaces

2001 ◽  
Vol 123 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Hans Rudolf Tschudi ◽  
Gerd Morian
Keyword(s):  
Solar Radiation ◽  
Temperature Measurements ◽  
Paul Scherrer Institute ◽  
Temperature Determination ◽  
Advantages And Disadvantages ◽  
Solar Reactor ◽  
Solar Blind ◽  
Multi Wavelength ◽  
Concentrated Solar Radiation ◽  
Paul Scherrer

Surface temperatures are key parameters in many applications of concentrated solar radiation. Pyrometric temperature determination is, however, hampered by reflected solar radiation. Two approaches to solve this problem were experimentally tested on a solar reactor at the Paul Scherrer Institute (PSI): the flash assisted multi-wavelength pyrometry (FAMP) developed at PSI and a solar-blind pyrometer developed by the IMPAC Electronic GmbH in Frankfurt, Germany, in collaboration with PSI. Performance, advantages, and disadvantages of the two pyrometers are reported and discussed.

scholarly journals Solar thermochemical splitting of CO2 into separate streams of CO and O2 with high selectivity, stability, conversion, and efficiency

2017 ◽  
Vol 10 (5) ◽  
pp. 1142-1149 ◽  
Author(s):  
Daniel Marxer ◽  
Philipp Furler ◽  
Michael Takacs ◽  
Aldo Steinfeld
Keyword(s):  
Solar Radiation ◽  
High Selectivity ◽  
Redox Cycle ◽  
Solar Reactor ◽  
Reactor Technology ◽  
Concentrated Solar Radiation ◽  
Solar Thermochemical

Solar reactor technology for splitting CO2via a 2-step thermochemical redox cycle using concentrated solar radiation.

Heat Transfer Model of a 50 kW Solar Receiver–Reactor for Thermochemical Redox Cycling Using Cerium Dioxide

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
S. Zoller ◽  
E. Koepf ◽  
P. Roos ◽  
A. Steinfeld
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Solar Radiation ◽  
Cerium Dioxide ◽  
Input Power ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Solar Reactor ◽  
Concentrated Solar Radiation ◽  
Solar Receiver

This work reports on the development of a transient heat transfer model of a solar receiver–reactor designed for thermochemical redox cycling by temperature and pressure swing of pure cerium dioxide in the form of a reticulated porous ceramic (RPC). In the first, endothermal step, the cerium dioxide RPC is directly heated with concentrated solar radiation to 1500 °C while under vacuum pressure of less than 10 mbar, thereby releasing oxygen from its crystal lattice. In the subsequent, exothermic step, the reactor is repressurized with carbon dioxide as it cools, and at temperatures below 1000 °C, the partially reduced cerium dioxide is re-oxidized with a flow of carbon dioxide. To analyze the performance of the solar reactor and to gain insight into improved design and operational conditions, a transient heat transfer model of the solar reactor for a solar radiative input power of 50 kW during the reduction step was developed and implemented in ANSYS cfx. The numerical model couples the incoming concentrated solar radiation using Monte Carlo ray tracing, incorporates the reduction chemistry by assuming thermodynamic equilibrium, and accounts for internal radiation heat transfer inside the porous ceria by applying effective heat transfer properties. The model was experimentally validated using data acquired in a high-flux solar simulator (HFSS), where temperature evolution and oxygen production results from model and experiment agreed well. The numerical results indicate the prominent influence of solar radiative input power, where increasing it substantially reduces reduction time of the cerium dioxide structure. Consequently, the model predicts a solar-to-fuel energy conversion efficiency of >6% at a solar radiative power input of 50 kW; efficiency >10% can be obtained provided the RPC macroporosity is substantially increased, and better volumetric absorption and uniform heating is achieved. Managing the ceria surface temperature during reduction to avoid sublimation is a critical design consideration for direct absorption solar receiver–reactors.

Solar Blind Pyrometer Temperature Measurements in High Temperature Solar Thermal Reactors: A Method for Correcting the System-Sensor Cavity Reflection Error

2005 ◽  
Vol 127 (1) ◽  
pp. 86-93 ◽  
Author(s):  
Aaron P. Freid ◽  
Paul K. Johnson ◽  
Manuela Musella ◽  
Reto Mu¨ller ◽  
Julie E. Steinbrenner ◽  
...  
Keyword(s):  
Narrow Band ◽  
Yttria Stabilized Zirconia ◽  
Temperature Measurements ◽  
Stabilized Zirconia ◽  
Uncertainty Interval ◽  
Measuring Surface ◽  
Band Filter ◽  
Solar Blind ◽  
Narrow Band Filter ◽  
Concentrated Solar Radiation

We developed a method that enables one to correct solar blind pyrometer cavity temperature measurements for the system-sensor reflection error. The method is valid for measurements made on diffusely emitting and reflecting cavity surfaces when there is no participating medium between the pyrometer and the surface of interest. The surfaces’ emissivities must be known. The procedure gives the uncertainty interval associated with the correction. The procedure was validated by measuring surface temperatures in a solar reactor insulated with Yttria-stabilized Zirconia felt receiving concentrated solar radiation. The temperature range of the experimental study was from 1100–1600 K. Temperature measurements made with a pyrometer having a narrow band filter centered at 1.398 μm were compared to temperatures measured with Zirconia felt shielded thermocouples. Uncorrected pyrometer measurements differed from the thermocouple measurements by as much as 350 K. The thermocouple measurements mostly fell within the system-sensor uncertainty interval of the corrected temperature measurements. The uncertainty interval depends both on the number of surfaces probed with the pyrometer and the nature of the solar blind filter. A numerical simulation study showed that a UV filter centered at a wavelength near 0.285 μm gives tighter system-sensor uncertainty intervals than an IR filter centered at 1.398 μm.

Pyrometric Temperature Measurements on Solar Thermal Receivers

Solar Energy ◽  
2005 ◽  
Author(s):  
Markus Pfa¨nder ◽  
Peter Heller ◽  
Eckhard Lu¨pfert
Keyword(s):  
Solar Radiation ◽  
Solar Thermal ◽  
Absorption Bands ◽  
Atmospheric Absorption ◽  
Efficient Operation ◽  
Solar Blind ◽  
Measurement Signal ◽  
Concentrated Solar Radiation ◽  
Spectral Ranges ◽  
Further Development

The knowledge of the absorber surface temperature distribution is essential for efficient operation and further development of solar thermal high temperature receivers. However, the concentrated solar radiation makes it difficult to determine the temperature on irradiated surfaces. Contact thermometry is not appropriate and pyrometric measurements are distorted by the reflected solar radiation. The measurement in solar-blind spectral ranges offers a possible solution by eliminating the reflected solar radiation from the measurement signal. The paper shows that besides the incoming solar radiation and the absorber emittance, the bi-directional reflection properties and the temperature of the object are determining for the required selectivity of the spectral filter. Atmospheric absorption affects the solar blind pyrometric measurements in absorption bands of CO2 and water vapor. The deviation of temperature measurement due to atmospheric absorption is quantified and the possibilities and limitations of accounting for the atmospheric absorption with models based on radiation transfer calculations are discussed.

Mechanically Aspirated Solar Radiation Shields: A CFD and Neural Network Design Analysis

2001 ◽  
Author(s):  
B. M. Fichera ◽  
R. L. Mahajan ◽  
T. W. Horst
Keyword(s):  
Neural Network ◽  
Solar Radiation ◽  
Temperature Sensor ◽  
Temperature Measurements ◽  
Analysis And Design ◽  
Computational Fluid Dynamics Analysis ◽  
Radiation Shields ◽  
Input Variables ◽  
The Relationship

Abstract Accurate air temperature measurements made by surface meteorological stations are demanded by climate research programs for various uses. Heating of the temperature sensor due to inadequate coupling with the environment can lead to significant errors. Therefore, accurate in-situ temperature measurements require shielding the sensor from exposure to direct and reflected solar radiation, while also allowing the sensor to be brought into contact with atmospheric air at the ambient temperature. The difficulty in designing a radiation shield for such a temperature sensor lies in satisfying these two conditions simultaneously. In this paper, we perform a computational fluid dynamics analysis of mechanically aspirated radiation shields (MARS) to study the effect of geometry, wind speed, and interplay of multiple heat transfer processes. Finally, an artificial neural network model is developed to learn the relationship between the temperature error and specified input variables. The model is then used to perform a sensitivity analysis and design optimization.

scholarly journals Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

2013 ◽  
Vol 31 (2) ◽  
pp. 333-336
Author(s):  
P.A. Ni ◽  
R.M. More ◽  
F.M. Bieniosek
Keyword(s):  
Ion Beam ◽  
Dense Matter ◽  
Warm Dense Matter ◽  
Emission Data ◽  
Reliable Determination ◽  
Temperature Determination ◽  
Multi Wavelength ◽  
Fitting In ◽  
Hot Surface

AbstractThis paper examines the reliability of a widely used method for temperature determination by multi-wavelength pyrometry. In recent warm dense matter experiments with ion-beam heated metal foils, we found that the statistical quality of the fit to the measured data is not necessarily a measure of the accuracy of the inferred temperature. We found a specific example where a second-best fit leads to a more realistic temperature value. The physics issue is the wavelength-dependent emissivity of the hot surface. We discuss improvements of the multi-frequency pyrometry technique, which will give a more reliable determination of the temperature from emission data.

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