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Hygrothermal performance of a masonry wall retrofitted with interior insulation
Published in J. Carmeliet, H. Hens, G. Vermeir, Research in Building Physics, 2020
M.N.A. Saïd, R.G. Demers, L.L. Mcsheffrey
Temperatures were measured, primarily, using type-T shielded thermocouple wire, accuracy ±0.5°C. Radiation shields were used for the interior and exterior air temperature sensors. RH was measured using humidity sensors with accuracy ±1% for 0 to 90% range and ±2% outside this range. Two air pressure transducers ranges were used, a ±250 Pa range for the cavity-to-indoor air pressure differential and a ±625 Pa range for the outdoor-to-indoor air pressure differential. The accuracy of the pressure transducers was ±0.14% of full scale. The stated accuracy of the heat flux sensor was ±5%. A calibration check at the National Research Council Canada indicated an accuracy of ±3%. Resistance measurements for the resistance-type moisture sensors were measured directly using a 10-charmel digital multimeter scanner, 300-MΩ range and ±2% accuracy, in conjunction with the data logger. All sensors were connected to a data acquisition system, which automatically sampled a total of 53 sensors once every minute. In addition to the one-minute data records, the data was averaged and saved every 10 minutes and every hour.
Practical Heat Flux Measurement
Published in Josua P. Meyer, Michel De Paepe, The Art of Measuring in the Thermal Sciences, 2020
A similar approach can be used to thermally interrogate complex systems, such as blood perfusion in the human body [26]. A thin-film heat flux sensor with a thermocouple (RdF, Hukseflux, or FluxTeq) is paired with a thin-film heater. The sensor is attached to the skin, and the heater is placed on top. After the sensor reaches the steady state, the heater is activated to produce a small rise in temperature with an appropriate heat flux. A sample of the resulting measurement is shown by the solid lines in Figure 12.15. The difference between the tissue surface and sensor temperatures is because of the thermal contact resistance between the sensor and the skin, R. In this case, the value of R =0.00037 m2 K/W. The heat flux event is started at about nine seconds and continues for fifty seconds. The temperature data are used to establish the boundary condition for a solution of the conduction equation including a perfusion term, wb. ρC∂θ∂t=k∂2θ∂x2−ρCwbθ
Innovations in Freeze-Drying Control and In-Line Optimization
Published in Davide Fissore, Roberto Pisano, Antonello Barresi, Freeze Drying of Pharmaceutical Products, 2019
Antonello Barresi, Roberto Pisano, Davide Fissore
The heat flux measurement has been recently developed and applied to process monitoring and control: at steady state, the sublimation flow is proportional to the heat flow to vials or trays, and as in previous cases the product temperature can be estimated from preliminary determination of the heat transfer coefficient (Vollrath et al. 2017) [see also Chapter 7]. The advantage of this method is that it can monitor several small clusters of (or single) vials, thus allowing distributed control, or the whole batch, depending on the surface covered by the sensor, and the heat flux measurement is not dependent on loading, unlike the mass flow measured with the TDLAS. However, at the moment the limit of the heat flux sensor is that it does not detect all heat from radiation; thus, calibration may be necessary, and this may be dependent on apparatus and scale. To improve the performance of the heat flux sensor it was proposed to modify the bottom of the vials (Chen et al. 2008), or to insert between the sensor and the vials a metallic foil.
Determination of exterior convective heat transfer coefficient for low-rise residential buildings
Published in Advances in Building Energy Research, 2021
All the temperatures (surface, air, ground) are measured by Uxcell MF52-103 NTC Thermistors with an accuracy of ± 0.1°C. The heat flux is measured by HFP01 heat flux sensor mounted on the exterior surface of the wall. The HFP01 heat flux sensor has an accuracy of ± 5% on walls. Heat transfer paste is also used with the heat flux sensor for higher quality heat transfer. The relative humidity is measured by HIH-4000 humidity sensors with an accuracy of ± 3.5%. An example of the outdoor wall sensor installation is shown in Figure 3.
Sm-Co-based amorphous alloy films for zero-field operation of transverse thermoelectric generation
Published in Science and Technology of Advanced Materials, 2022
Rajkumar Modak, Yuya Sakuraba, Takamasa Hirai, Takashi Yagi, Hossein Sepehri-Amin, Weinan Zhou, Hiroto Masuda, Takeshi Seki, Koki Takanashi, Tadakatsu Ohkubo, Ken-ichi Uchida
Here, we demonstrate the performance of the SmCo-based amorphous films as a flexible heat flux sensor based on ANE. The heat flux sensor is a device enabling quick and simultaneous detection of the magnitude and direction of a heat flow, which can be an essential component for smart thermal management systems. However, till now, the commercial applications of heat flux sensors are confined due to several limitations. The commercially available sensors are based on the Seebeck effect and constructed from a serially connected three-dimensional matrix of two different thermoelectric materials. Therefore, the Seebeck-effect-based heat flux sensors require a durable substrate or thick plate to provide mechanical stability. Hence, the conventional sensors are mainly applicable to flat surfaces and the flexibility is limited. Due to the presence of thick substrates, these sensors have large thermal resistance that disturbs the heat flow. Although the sensibility of the Seebeck-effect-based heat flux sensors is proportional to the number of the thermoelectric material junctions and to the sensor size, the complex structure and low mechanical durability make it difficult to enlarge the sensor size. As an alternative to the Seebeck-effect-based heat flux sensors having these limitations, researchers proposed thin-film-based heat flux sensors driven by ANE [24,39,40]. In the ANE-based sensor, a lateral thermopile structure consisting of alternately arranged and serially connected two different conductor wires with different ANE coefficients is used. Owing to this simple thermopile structure and the symmetry of ANE, the device can be thin, making it easy to reduce the thermal resistance. If magnetic materials showing large ANE can be formed on thin flexible sheets, flexible heat flux sensors can be constructed. These features of the ANE-based heat flux sensors are advantageous over the Seebeck-effect-based heat flux sensors.