scholarly journals A simple method for estimating thermal response of building materials in tropical climate

2001 ◽  
Vol 7 (1) ◽  
Author(s):  
E E IHEONU
Keyword(s):  
Building Materials ◽  
Thermal Response ◽  
Tropical Climate ◽  
Simple Method

scholarly journals Novel active method for the estimation of a building wall thermal resistance

2020 ◽  
Vol 172 ◽  
pp. 14008
Author(s):  
Adrien François ◽  
Laurent Ibos ◽  
Vincent Feuillet ◽  
Johann Meulemans
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Building Materials ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Heat Fluxes ◽  
External Temperature ◽  
Building Wall ◽  
High Thermal Inertia

The thermal resistance of a wall can be readily measured in steady-state. However, such a state is seldomly achieved in a building because of the variation of outdoor conditions as well as the high thermal inertia of building materials. This paper introduces a novel active (dynamic) method to measure the thermal resistance of a building wall. Not only are active approaches less sensitive to external temperature variations, they also enable to perform measurements within only a few hours. In the proposed methodology, an artificial thermal load is applied to a wall (heating of the indoor air) and its thermal response is monitored. Inverse techniques are used with a reduced model to estimate the value of the thermal resistance of a wall from the measured temperatures and heat fluxes. The methodology was validated on a known load-bearing wall built inside a climate chamber. The results were in good agreement with reference values derived from a steady-state characterization of the wall. The method also demonstrated a good reproducibility.

scholarly journals Thermal Sensation in Courtyards: Potentialities as a Passive Strategy in Tropical Climates

2020 ◽  
Vol 12 (15) ◽  
pp. 6135 ◽  
Author(s):  
Ivan Julio Apolonio Callejas ◽  
Luciane Cleonice Durante ◽  
Eduardo Diz-Mellado ◽  
Carmen Galán-Marín
Keyword(s):  
Climate Change ◽  
Urban Areas ◽  
Thermal Sensation ◽  
Thermal Response ◽  
Tropical Climate ◽  
Design Strategies ◽  
Physiological Equivalent Temperature ◽  
Synoptic Conditions ◽  
The Impact ◽  
Passive Strategy

Climate change will bring changes to our living conditions, particularly in urban areas. Climate-responsive design strategies through courtyards can help to moderate temperatures and reduce the thermal stress of its occupants. Thermal response inside courtyard is affected not only by its morphological composition but also by subjective factors. Thus, standardized thermal scales may not reflect the stress of the occupants. This study investigated the impact on thermal attenuation provided by a courtyard located in a tropical climate under extreme cold and hot synoptic conditions by means of local thermal sensation scales. Microclimatic variables were monitored, simultaneously with the application of a thermal comfort questionnaire, by using weather stations installed outside and inside the courtyard. The Modified Physiological Equivalent Temperature Index (mPET) was utilized to predict the heat stress. Calibration was conducted using linear regression to attribute particular thermal sensation votes to correspondent mPET values. It was found that thermal sensation can be affected by factors such as psychological, behavioral, and physiological. The courtyard’s form provides a passive cooling effect, stabilizing interior thermal sensation, with attenuation peaks of 6.4 °C on a cold day and 5.0 °C on a hot day. Courtyards are an alternative passive strategy to improve thermal ambience in tropical climate, counterbalancing climate change.

scholarly journals Proposition of a simplified method for predicting hourly indoor temperatures in test cells

2017 ◽  
Vol 17 (3) ◽  
pp. 57-70 ◽  
Author(s):  
Eduardo Leite Krüger ◽  
Leandro Fernandes ◽  
Grace Tibério Cardoso ◽  
Emilio Eiji Kavamura
Keyword(s):  
Indoor Air ◽  
High Performance ◽  
Building Materials ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Measured Data ◽  
Indoor Temperature ◽  
Simple Method ◽  
Air Temperatures ◽  
Test Cells

Abstract Test cells can be used for testing the thermal performance of different passive systems and building components. Predictive methods for estimating indoor air temperatures can further enhance the number of configurations tested without increasing the amount of test cells to be built. Thus, direct comparisons can be drawn for identical background climatic conditions. In its most basic form, formulas are generated by linear regression from relatively short data sets, which provide daily indoor temperature conditions. However, for more detailed analyses, daily indoor temperature predictions may not suffice. In this paper, a method for obtaining hourly indoor air temperature predictions is proposed. It is based on rising and decreasing rates of the indoor temperature fluctuation relative to outdoors, which translates to warming or cooling trends of indoor thermal conditions. The applicability of the method is for test cells. It is a simple method yet capable of predicting the thermal behavior of complex physical processes. The method was tested using measured data from experiments in a test cell, built with conventional building materials in Brazil. Results showed high performance with mean bias of 0.27 °C to measured data and Pearson's r 0.99. When compared to traditional regression-based models, the method proposed showed better results.

scholarly journals Utilization of Industrial Waste in Cement in a Marine Environment with a Tropical Climate

2019 ◽  
Vol 7 (8) ◽  
pp. 245 ◽  
Author(s):  
Thi Chu ◽  
Jinhai Zheng ◽  
Da Chen ◽  
Thi Nguyen ◽  
Elsafi Elbashiry ◽  
...  
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Marine Environment ◽  
Industrial Waste ◽  
Building Materials ◽  
Rapid Development ◽  
Chloride Ion ◽  
Tropical Climate ◽  
Test Results

This novel study on cement paste material was conducted with the aim of keeping up with the rapid development of urban construction and contributing to the continuous improvement of building materials to overcome environmental issues. In this study, several kinds of industrial waste were used to enhance the properties of cement paste for application in a marine environment with a tropical climate, such as in Vietnam. This study focuses on evaluating the properties of cement paste containing cement replacement combining 0–30% fly ash, 0–10% silica fume, and plasticizer accounting for 0.3% and 0.4% of the binder by mass. Water demand, chloride ion and sulfate ion permeability, and microstructural properties of the cement paste were determined by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscope (SEM) and they were investigated after 28 and 56 days. The test results show that an optimum mixture could be obtained with the use of 20% fly ash, 10% silica fume (replacing Portland cement), and 0.4% plasticizer. The application of such materials to sea dikes affected by a tropical climate (characterized by heat, humidity, salty seawater, many big storms, large waves, and strong tides) was investigated for four years on the Vietnamese coast. The test results indicate that fly ash and silica fume can improve the corrosion and abrasion resistance of concrete in coastal areas with a tropical climate, such as in Vietnam.

scholarly journals Influence of Supersaturation, Temperature and Rotational Speed on Induction Time of Calcium Sulfate Crystallization

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1236
Author(s):  
Agata Małysiak ◽  
Szymon Orda ◽  
Michał Drzazga
Keyword(s):  
Data Analysis ◽  
Rotational Speed ◽  
Induction Time ◽  
Calcium Sulfate ◽  
Building Materials ◽  
Simple Method ◽  
Turbidimetric Method ◽  
Impression Materials ◽  
Time Calculation ◽  
Tablet Excipients

Calcium sulfate is a very important product of precipitation reactions in various branches of industry. The most common applications include building materials, impression materials in dentistry, immobilizing casts and an inactive ingredient of tablet excipients. It is also used as a drying agent and color glaze. In this paper, influence of various conditions, i.e., substrates concentration (supersaturation), temperature and rotational speed on induction time was investigated. The range of investigated parameters was 0.15–0.35 M for concentration with step of 0.05 M, 298–323 K with step of 5 K for temperature, and 1.67–8.33 s−1 for rotational speed with change every 1.67 s−1. The experiments were performed using visual and turbidimetric methods. It was proven that increase in all three investigated parameters resulted in shorter induction time. The turbidimetric method was found to be more precise, but still insufficient for concentrations below 0.15 M. Moreover, as a result of data analysis, a simple method of induction time calculation was proposed when arbitrary measurements in various concentrations are known.

scholarly journals Role of Local Building Materials on the Energy Behaviour of Habitats in Ouagadougou

2017 ◽  
Vol 8 (2) ◽  
pp. 63
Author(s):  
Abdoulaye COMPAORE ◽  
Boukaré OUEDRAOGO ◽  
Hassime GUENGANE ◽  
Etienne MALBILA ◽  
D. Joseph BATHIEBO
Keyword(s):  
Energy Efficiency ◽  
Building Materials ◽  
Numerical Study ◽  
Construction Materials ◽  
Thermal Response ◽  
Computer Code ◽  
Good Alternative ◽  
Local Construction ◽  
One Year ◽  
Modern Building

<p>The present work is a contribution to the energy efficiency in the habitats by the valorization of the local building materials in Burkina Faso. A comparative numerical study on the thermal behavior and energy consumption of some habitats in local and modern building materials is carried out. The simulations were carried out using computer code written in FORTRAN language over a period of one year. Analysis of the results shows that habitats in local construction materials (BTC, BLT, adobe) have a better thermal response compared to modern building materials (hollow cinder block). Generally speaking, the temperature and humidity profiles obtained do not make it possible to ensure the summer comfort in these buildings throughout the year. The evaluation of air-conditioning loads to ensure thermal comfort in these habitats shows that they are higher respectively in the blocks, BLT, BTC, adobe constructions. We therefore consider that local building materials represent a good alternative for the search for energy efficiency in buildings.</p>

Transient and Steady State Thermal Response of a System With Thermoelectric Coolers

2017 ◽  
Author(s):  
Kayvan Abbasi ◽  
Sukhvinder Kang
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Time Scales ◽  
Thermoelectric Module ◽  
Thermal Response ◽  
Thermal Mass ◽  
Thermoelectric Cooler ◽  
Simple Method ◽  
Thermoelectric Coolers ◽  
Transient And Steady State

The transient and steady state response of a thermal system with thermoelectric coolers has been studied analytically. The system is comprised of a device with thermal mass inside an insulated enclosure, thermal resistance between the mass and the thermoelectric cooler, insulation thermal resistance, TIM between thermoelectric cooler layers, and a heatsink on the hot side of the thermoelectric cooler. It is assumed that the thermal mass of the thermoelectric cooler is negligible compared to other thermal masses. The analytical transient solution consists of two exponential eigen functions and hence two time scales (i.e. two eigen values). The analytical solution has been validated with a numerical Runge-Kutta solution. A simple method is explained to combine thermoelectric coolers in series and parallel. The time scales are studied for different parameters and the key parameters for time scale minimization are identified. It is found that the thermoelectric module thermal resistance limits the fastest transient response.

Smart and Cool Home in Malaysia

2011 ◽  
Vol 224 ◽  
pp. 115-119 ◽  
Author(s):  
Ismail Muhammad Azzam ◽  
Abdul Rashid Fahanim
Keyword(s):  
Thermal Comfort ◽  
Heat Sink ◽  
Urban Areas ◽  
Indoor Environment ◽  
Building Materials ◽  
Tropical Climate ◽  
Building Envelope ◽  
Thermal Mass ◽  
Innovative Strategies

Achieving thermal comfort in the tropical climate of Malaysia is always a great challenge for any house designer or builder. Although some practical solutions have been developed over centuries through the slow but constant evolution of indigenous houses such the Malay house, the longhouses in Borneo and the Chinese townhouses in Melaka, their integration into contemporary designs have been hampered by various modern constraints. For instance, building the Malay house in urban areas is deemed unsuitable due to the need for wide land lots and their perceptively fragile building materials that do not allay any security worries. The lack of skilled carpenters for building such a house is also a worsening problem. Hence, new and innovative strategies to achieve thermal comfort for contemporary houses are greatly needed to serve the needs and expectations of an urbanized society. One method that has been studied and proved successful is the Smart and Cool Home system which was first used at a private bungalow in Semenyih, Malaysia. The overarching principle of this system is to reverse the role of the building envelope from being a thermal mass into a heat sink which effectively reduces heat gains and allow the occupants inside to easily adapt to a milder indoor environment. This paper describes this house in detail and provides some understanding of the principles involved.

scholarly journals Producing superhydrophobic/oleophobic coatings on Cultural Heritage building materials

2018 ◽  
Vol 90 (3) ◽  
pp. 551-561 ◽  
Author(s):  
Maria J. Mosquera ◽  
Luis A.M. Carrascosa ◽  
Nabil Badreldin
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Cultural Heritage ◽  
Building Materials ◽  
Contact Angle Hysteresis ◽  
Simple Method ◽  
Cleaning Performance ◽  
Static Contact ◽  
Heritage Building ◽  
Building Surfaces

AbstractWater is the main vehicle of decay agents in Cultural Heritage building materials exposed to weathering. In this work, a simple method to produce superhydrophobic/oleophobic coatings building materials, including under outdoors conditions, has been developed. In addition, a study of the behavior of the developed coatings on different substrates (limestone, granite, concrete and wood) is reported. The addition of 40 nm-SiO2nanoparticles to a fluoroalkylsilane reduces surface energy and produces a Cassie-Baxter surface in all the materials evaluated. It promotes high static contact angle values of around 160°, and a contact angle hysteresis of around 3°, giving rise to repellence. The building surfaces also demonstrate an excellent self-cleaning performance. The coatings maintain the building materials esthetics as required in the Cultural Heritage field. Finally, the coating presents a long-lasting performance due to condensation reactions producing effective grafting to the four building materials evaluated.

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