Comparison of the thermal performance between conventional and cob building

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base

Realization and thermal characterization of thin-film optothermal microsensor

The aim of this investigation is to study thin-film thermoelectric linear arrays for high spatial temperature measurements and to analyze power laser energy profile. The sensitive area consists of a planar of 16 individual thin-film Au-Pd thermocouple junctions with 8 μm × 8 μm of surface area. This sensor allows 16 temperature measurements per 288 μm. It is processed by means of standard integrated circuit techniques. Thermal simulation of heat conduction in gold and palladium layers has been carried out. The sensor thermoelectric response has been characterized in transient regime and steady state. The time constant of thermocouple response is of the order of 140 μs. A linear relationship between the thermoelectric voltage and the incident power laser has been put in evidence. Using the linear array, a Gaussian profile of the incident laser beam is obtained

Unsteady steam condensation flow patterns inside a miniature tube

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Experimental study of void fraction profils in pool boiling on a vertical surface

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Experimental Study of Unsteady Local Heat Transfer for Impinging Miniature Jet

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Numerical Modeling of Annular Film Condensation Inside a Miniature Tube

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Experimental and numerical investigations of local condensation heat transfer in a single square microchannel under variable heat flux

International audienceThis paper presents an experimental investigation on the local and average condensation heat transfer in a single noncircular microchannel. Furthermore, it develops one dimensional model for annular condensation flow in a microchannel under variable heat flux condition. The condensate film thickness is calculated for each location in a microchannel including the effects of capillary number, Boiling number, contact angle, heat flux, vapor pressure, and hydraulic diameter. A comparative study shows that the present model well predicts the experimental data concerning local condensation heat transfer coefficient. The mean deviation between the local predictions of the theoretical model with the measurements for local heat transfer coefficient is 20%. It is found that the correlation of Quan et al. (2008) [19] gives the good predictions of the measurements with maximum deviation of 13% at high Reynolds number

Local Heat Transfer for the Evaporation of a Laminar Falling Liquid Film on a Cylinder: Experimental, Numerical, and Inverse Heat Conduction Analysis

International audienceThis article presents the experimental, numerical, and inverse heat conduction (IHCP) analysis of the evaporation heat transfer of a falling liquid film on a horizontal cylinder. The two-dimensional IHCP is solved in order to determine the surface temperature, local heat flux, and local heat transfer coefficient for the sheet flow. The local surface temperature is used as the boundary condition in the mathematical model for the falling film evaporation, where the coupled boundary-layer equations of the liquid and gas phases are solved numerically. The local and average heat transfer coefficients estimated by the IHCP and the numerical evaporation model are in good agreement. The local heat transfer increases with increasing liquid mass flow rate, air flow velocity, the radius of the tube, and with decreasing inlet bulk film temperature