The effects of thermistor linearization techniques on the T-history characterization of phase change materials

Stanković, Stanislava B.; Kyriacou, Panayiotis A.

doi:10.1016/j.applthermaleng.2012.03.032

Cited by 22 publications

(10 citation statements)

References 18 publications

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“…Unknown temperature T 1 is defined by measuring R 1 and using ratio R 1 /R 0 (4). The methods for calibration and linearization of NTC thermistors for high precision temperature measurements are given in literature [70][71][72]. The temperature gradient (in the air, water or ground) can be measured by segmented thick film thermistors using inner electrodes (see figure 7): for measured resistances R 1 ,R 2 ,R 3 and R 4 on segments, for example, temperatures Т 1 ,Т 2 ,Т 3 and Т 4 are determined using equation 4, respectively.…”

Section: Thick Film Thermistor Sensors and Systemsmentioning

confidence: 99%

Recent advances in NTC thick film thermistor properties and applications

Aleksic

Nikolić

2017

FACTA U EE

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An introduction to thermal sensors and thermistor materials is given in brief. After that novel electrical components such as thick film thermistors and thermal sensors based on them are described: Custom designed NTC thermistor pastes based on nickel manganite NiM 2 O 4 micro/nanostructured powder were composed and new planar cellbased (segmented) constructions were printed on alumina. The thick film segmented thermistors were used in novel thermal sensors such as anemometers, water flow meters, gradient temperature sensor of the ground, and other applications. The advances achieved are the consequence of previous improvements of thermistor material based on nickel manganite and modified nickel manganite such as Cu 0.2 Ni 0.5 Zn 1.0 Mn 1.3 O 4 and optimization of thick film thermistor geometries for sensor applications. The thermistor powders where produced by a solid state reaction of MnCO 3 , NiO, CuO, ZnO powders mixed in proper weight ratio. After calcination the obtained thermistor materials were milled in planetary ball mils, agate mills and finally sieved by 400 mesh sieve. The powders were characterized by XRD and SEM. The new thick film pastes where composed of the powders achieved, an organic vehicle and glass frit. The pastes were printed on alumina, dried and sintered and characterized again by XRD, SEM and electrical measurements. Different thick film thermistor constructions such as rectangular, sandwich, interdigitated and segmented were printed of new thermistor pastes. Their properties such as electrical resistance of the thermistor samples where mutually compared. The electrode effect was measured for all mentioned constructions and surface resistance was determined. It was used for modeling and realizations of high, medium and low ohmic thermistors with different power dissipation and heat loss. Finally all the results obtained lead to thermal sensors based on heat loss for measuring the air flow, water flow, temperature gradient and heat transfer from the air to the ground.

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Section: Thick Film Thermistor Sensors and Systemsmentioning

confidence: 99%

Recent advances in NTC thick film thermistor properties and applications

Aleksic

Nikolić

2017

FACTA U EE

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“…Therefore, an appropriate instrumentation system for thermistor linearisation, signal amplification and filtering had to be used. The relevant linearisation and calibration procedures are explained in detail in a recent publication [16]. The obtained temperature uncertainty was ±0.3 °C.…”

Section: Thermal Characterisationmentioning

confidence: 99%

Experimental and numerical investigations of the optical and thermal aspects of a PCM-glazed unit

Gowreesunker

Stanković

Tassou

et al. 2013

Energy and Buildings

121

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This paper reports on the experimental and numerical analysis of the optical and thermal aspects of PCM (Phase Change Material) RT27 when subjected to an irradiation source of energy. The analysis is separated into the thermal and optical characterisation of the PCM using the T-history method and spectrophotometry principles, respectively, and the experimental and numerical performance evaluation of a PCM-Glazed unit. Various relationships describing the variations in the extinction, scattering and absorption coefficients with respect to the liquid fraction/ temperature within the phase change region were developed from the experimental setup, and were validated in a numerical CFD model. The results show that: i) during rapid phase changes, the transmittance spectra from the PCM are unstable, while under stable conditions a visible transmittance value of 90% and 40% are obtained for the liquid and phases, respectively; ii) the radiation scattering effects are more prominent in the solid phase of the PCM, while radiation absorption dominates in the liquid phase; iii) the optical/ radiation performance of PCM can be successfully modelled using the liquid fraction term as the main variable, in a similar way that the enthalpy porosity method is employed for phase change processes; iv) relative to a standard double glazed unit, the addition of PCM improves the thermal mass of the unit during phase change, but depending on specific

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“…The BINDER KMF 115 chamber was used as the temperature control facility in the calibration procedure. Calibration is not explained in detail in this paper since the whole procedure is thoroughly given in [25]. The thermistor linearization techniques were developed so the minimum uncertainty of ±0.1 °C is introduced by the thermistor alone.…”

Section: Methodsmentioning

confidence: 99%