Heat flux sensors: Calorimeters or radiometers?

Ballestrín, Jesús; Estrada, Claudio A.; Rodríguez-Alonso, M; Pérez-Rábago, Carlos; Langley, Lawrence W.; Barnes, Adam

doi:10.1016/j.solener.2006.03.005

Cited by 36 publications

(13 citation statements)

References 7 publications

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“…The Gardon gauge used to measure irradiance was calibrated by a high-accuracy calorimetric procedure 30 and found to have an uncertainty of ±3.0%. The Gardon gauge used to measure irradiance was calibrated by a high-accuracy calorimetric procedure 30 and found to have an uncertainty of ±3.0%.…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…According to instrumentation manufacturers, temperatures were acquired with an uncertainty of ±1.5 K, differential pressure within ±0.8%, and mass flow rates within ±0.5%. The Gardon gauge used to measure irradiance was calibrated by a high-accuracy calorimetric procedure 30 and found to have an uncertainty of ±3.0%. Errors introduced in the signal amplification and analogue-to-digital conversion process were estimated to be upper bound at 0.025%.…”

Section: Uncertainty Analysismentioning

confidence: 99%

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A new calorimetric facility to investigate radiative-convective heat exchangers for concentrated solar power applications

et al. 2017

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Summary A new calorimetric facility for the aerothermal assessment of radiative‐convective heat exchangers in concentrating solar power applications has been developed and is described in this paper. The configuration of volumetric solar receivers enables concentrated sunlight to be absorbed and conducted within their solid volume, from where it is gradually transferred by forced convection to a heat transfer fluid flowing through their structure. Current design trends towards higher thermal conversion efficiencies have led to the use of complex intricate geometries to maximise temperatures deep inside the structure. The work presented aims to aid these objectives by commissioning a new experimental facility for the fully integrated evaluation of such components. The facility is composed of a high‐flux solar simulator that provides 1.2 kW of radiative power, a radiation homogeniser, inlet and outlet collector modules, and a working section that can accommodate volumetric receivers up to 80 mm × 80 mm in aperture. Irradiance levels and flow field nondimensional governing parameters are highly representative of on‐sun experiments at larger scales. Results from experiments with a siliconised silicon carbide monolithic honeycomb are presented, conducted at realistic conditions of incident radiative power per unit mass flow rate to validate its design point operation. Measurements conducted include absorber solid temperature distributions, air inlet and outlet temperatures, pressure drop, incident heat flux, and overall thermal efficiency. The relative influence of different sources of thermal loss is analysed and discussed.

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Section: Uncertainty Analysismentioning

confidence: 99%

Section: Uncertainty Analysismentioning

confidence: 99%

A new calorimetric facility to investigate radiative-convective heat exchangers for concentrated solar power applications

et al. 2017

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“…Since they cannot be biased, only non-electrostatic calibration methods are suited for this purpose. Usually, a black-body radiator is used as a source of known power [61][62][63][64].…”

Section: Calibration Of Passive Probesmentioning

confidence: 99%

Calorimetric Probes for Energy Flux Measurements in Process Plasmas

2014

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This chapter gives an overview of the method of calorimetric probes which are used for characterizing the interaction between low-temperature plasmas and substrates in materials processing. Although the focus is on low-temperature nonequilibrium plasmas most of the concepts can also be transferred to thermal plasmas or are in fact adopted from fusion research. An introductory section showing the importance and complexity of plasma wall interactions is followed by a section providing an overview and comparison of various probe concepts, which have been developed in the last decades. Special focus is on the type of probes which are similar to the probes used by J.A. Thornton (In fact, Thornton was not the first, to use this type of probe. From his work from 1978 [1], one can follow the citations back to the work of Jackson in 1969, who used equation (6.7) for the determination of the power dissipated by a copper block located at substrate position in a sputtering discharge [2]) who was one of the pioneers connecting plasma characteristics with resulting surface properties. Thereafter, a short section gives a basic overview of the different contributions to the total energy influx and which are of importance for the plasma wall interaction. The last section shows different examples of applications of calorimetric probes. It demonstrates the applicability and flexibility of these types of probes for characterization of different low-temperature plasmas. The examples

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“…Ballestr ın et al [23] suggest a calibration method that uses the Gardon sensor as calorimeter by measuring inlet and outlet cooling water temperatures. As an electrically heated furnace is used, the calibration constants are corrected to be used with solar radiation.…”

Section: Introductionmentioning

confidence: 99%

“…As an electrically heated furnace is used, the calibration constants are corrected to be used with solar radiation. The achieved measurement uncertainties are estimated in the range of 2% [23].…”

Section: Introductionmentioning

confidence: 99%

Techniques to Measure Solar Flux Density Distribution on Large-Scale Receivers

Röger¹,

Herrmann

Ulmer³

et al. 2014

Journal of Solar Energy Engineering

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Flux density measurement applied to central receiver systems delivers the spatial distribution of the concentrated solar radiation on the receiver aperture, measures receiver input power, and monitors and might control heliostat aimpoints. Commercial solar tower plants have much larger aperture surfaces than the receiver prototypes tested in earlier research and development (R&D) projects. Existing methods to measure the solar flux density in the receiver aperture face new challenges regarding the receiver size. Also, the requirements regarding costs, accuracy, spatial resolution, and measuring speed are different. This paper summarizes existent concepts, presents recent research results for techniques that can be applied to large-scale receivers and assesses them against a catalog of requirements. Direct and indirect moving bar techniques offer high measurement accuracy, but also have the disadvantage of large moving parts on a solar tower. In the case of external receivers, measuring directly on receiver surfaces avoids moving parts and allows continuous measurement but may be not as precise. This promising technique requires proper scientific evaluation due to specific reflectance properties of current receiver materials. Measurement-supported simulation techniques can also be applied to cavity receivers without installing moving parts. They have reasonable uncertainties under ideal conditions and require comparatively low effort.

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Heat flux sensors: Calorimeters or radiometers?

Cited by 36 publications

References 7 publications

A new calorimetric facility to investigate radiative-convective heat exchangers for concentrated solar power applications

A new calorimetric facility to investigate radiative-convective heat exchangers for concentrated solar power applications

Calorimetric Probes for Energy Flux Measurements in Process Plasmas

Techniques to Measure Solar Flux Density Distribution on Large-Scale Receivers

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