scholarly journals A mathematical model for predicting the indoor moisture variation by using moisture buffering theory

2021 ◽  
Vol 2069 (1) ◽  
pp. 012036
Author(s):  
Kan Zu ◽  
Menghao Qin
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Indoor Air ◽  
Building Materials ◽  
Air Humidity ◽  
Acceptable Solution ◽  
Moisture Variation ◽  
Buffer Value ◽  
Moisture Buffering ◽  
Moisture Buffer Value

Abstract Indoor air humidity evaluation plays an of great importance role on the thermal comfort and building energy consumption. The utilization of hygroscopic materials as building materials acts on the indoor air humidity by regulating its humidity fluctuations, and then reduces a certain fraction of energy consumption on the air conditioning systems. Based on the Fick’s law, the physical process inside these hygroscopic materials requires the determinations of hygrothermal properties, which signify the extensive and reiterative experiments. While in many building simulation toolboxes, moisture buffering behavior has been evaluated by either simple approximations or complicated heat and mass model. In this case, we developed a mathematical model about the moisture transport with acceptable solution time and accuracy in terms of the moisture buffer value (MBV) theory. Considering that MBV originally represents the moisture buffering capacity of those hygroscopic materials, we did some mathematical deduction about MBVs under different boundary conditions. Then the definition of time-average MBV has been used, and all the required parameters was obtained from the practical MBV test. By comparing the new moisture buffer value model (MBM) with HAMT model, the results indicated that MBM could provide reasonably accurate prediction for indoor moisture variation.

Study of Moisture Buffering in Building Materials with Application of Sorption Kinetics Models

2010 ◽  
Vol 297-301 ◽  
pp. 1232-1237 ◽  
Author(s):  
N.M.M. Ramos ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Building Materials ◽  
Moisture Absorption ◽  
Stationary Process ◽  
Sorption Kinetics ◽  
Temperature Level ◽  
Kinetics Models ◽  
Buffer Value ◽  
Experimental Values ◽  
Moisture Buffering ◽  
Moisture Buffer Value

This work presents experimental values of Moisture Buffer Value (MBV) obtained with three different samples of building materials, using a non-stationary process of moisture absorption. The tests carried out at the laboratory tried to explore the importance of some of the variables that can interfere in the final results, such as materials themselves, temperature level and the use of finishing coatings. The experimental data obtained at 15°C and 23°C were then analyzed using the second order sorption kinetic model. The application of kinetics models to the experimental results was explored and several parameters were retrieved. A proposal for the use of these parameters is presented and its practical use is discussed.

scholarly journals The Effects of Natural Paint on the Moisture Buffering Ability of Paper Plaster

2020 ◽  
Vol 57 (5) ◽  
pp. 51-60
Author(s):  
N. Nutt ◽  
A. Kubjas ◽  
L. Nei ◽  
A. Ruus
Keyword(s):  
Relative Humidity ◽  
Indoor Air ◽  
Waste Paper ◽  
Moisture Permeability ◽  
Daily Variations ◽  
Number Of Layers ◽  
Buffer Value ◽  
Moisture Buffering ◽  
Moisture Buffer Value

AbstractThe scope of the Nordtest method is to evaluate the moisture buffer value (MBV) of materials exposed to indoor air. The test is intended to simulate daily variations with relative humidity (RH) between 75 % during 8 hours and 33 % during 16 hours.The specimens follow a recipe that consists of waste paper, glue and water. Specimens made of paper plaster were covered with different colours.The results of the experiment showed that the type of paint used and the number of layers applied affected the MBV. Natural colours have a better moisture permeability than chemical paints, but the number of natural colour layers affects the MBV. The higher the number of layers, the lower the MBV.

scholarly journals Moisture Buffering of Multilayer Internal Wall Assemblies at the Micro Scale: Experimental Study and Numerical Modelling

2019 ◽  
Vol 9 (16) ◽  
pp. 3438 ◽  
Author(s):  
Dobrosława Kaczorek
Keyword(s):  
Penetration Depth ◽  
Buffering Capacity ◽  
Internal Wall ◽  
Simplified Method ◽  
Buffer Value ◽  
Series Of Experiments ◽  
Overall Performance ◽  
Wall Assembly ◽  
Moisture Buffering ◽  
Moisture Buffer Value

In this paper, a series of experiments assessing the moisture buffer value (MBV) of four internal wall assembly samples made from hygroscopic materials was performed. A modified Nordtest protocol was used. Moisture buffer values of all the investigated wall assemblies, with varying moisture loads in the range of 50% to 80%, showed a moderate moisture buffer value (MBV: 0.5–1.0 (g·m−2·%RH−1)). The results showed that in a wall assembly where the MBV of the whole assembly is lower than the MBV of the outer layers, the moisture-buffering capacity of the inner layer is untapped. Outer layers affect inner layers by changing their moisture-buffering capacity, which in turn changes the overall performance of the whole assembly. In addition, it was observed that if the penetration depth value of the outer layer is greater than its thickness, vapour reaches into the deeper layer and wall assemblies made of layers with materials characterized by a lower value of penetration depth reach steady state more slowly. The WUFI Pro tool was used to compare the simulated and experimental results. Despite the discrepancies between these results, it offers a simplified method, helping designers make decisions about which materials to choose to improve the moisture-buffering effect.

scholarly journals Moisture Buffer Value of Building Materials

2009 ◽  
pp. 33-33-12
Author(s):  
Carsten Rode ◽  
Ruut Peuhkuri ◽  
Berit Time ◽  
Kaisa Svennberg ◽  
Tuomo Ojanen
Keyword(s):  
Building Materials ◽  
Buffer Value ◽  
Moisture Buffer Value

scholarly journals Moisture Buffer Value of Building Materials

2007 ◽  
Vol 4 (5) ◽  
pp. 100369 ◽  
Author(s):  
Carsten Rode ◽  
Ruut Peuhkuri ◽  
Berit Time ◽  
Kaisa Svennberg ◽  
Tuomo Ojanen ◽  
...  
Keyword(s):  
Building Materials ◽  
Buffer Value ◽  
Moisture Buffer Value

scholarly journals Moisture Buffer Value of Composite Material Made of Clay- Sand Plaster and Wastepaper

2020 ◽  
Vol 27 (2) ◽  
pp. 108-115
Author(s):  
Nele Nutt ◽  
Ardo Kubjas
Keyword(s):  
Composite Material ◽  
Relative Humidity ◽  
Indoor Air ◽  
Large Percentage ◽  
Waste Paper ◽  
Daily Variations ◽  
Impressive Result ◽  
Buffer Value ◽  
Moisture Buffer Value

The scope of the Nordtest method is to evaluate the moisture buffer value (MBV) for materials exposed to indoor air. The test is intended to simulate daily variations with relative humidity (RH) of 75% during 8 hours and 33% during 16 hours.Many authors have noted that clay plaster has a very good MBV (Altmäe et al. 2019). Our previous tests have shown that the MBV of clay plaster can be increased by adding paper plaster mixture (Nutt et al. 2020a). The specimen made according to a recipe contains the following: waste paper, glue, clay plaster mixture and water. Eleven paper plaster mixtures with different percentages were used.Test results showed that a large percentage of paper in the plaster increases the MBV. An impressive result, which needs to be studied further, was that the MBV was the highest in the mixture that consisted of 80% paper.

scholarly journals Bake-Out Strategy Considering Energy Consumption for Improvement of Indoor Air Quality in Floor Heating Environments

2018 ◽  
Vol 15 (12) ◽  
pp. 2720 ◽  
Author(s):  
Seonghyun Park ◽  
Janghoo Seo
Keyword(s):  
Energy Consumption ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Building Materials ◽  
Significant Loss ◽  
Computational Fluid Dynamics Analysis ◽  
Heating Energy Consumption ◽  
Floor Heating

Improved quality of life has led to a growing demand for better indoor air quality (IAQ). Buildings are becoming more airtight and insulated in order to minimize energy consumption. The importance of both energy conservation and IAQ improvement has been recognized and addressed by many studies. Bake-out is the process of using indoor heating to remove volatile compounds present in building materials and furnishings so that they can be vented out into the atmosphere. Indiscriminate use of heating to increase the surface temperature of materials during this process can result in significant loss of energy. Therefore, energy-efficient bake-out should be performed by considering both the floor temperature and the emission amount of pollutants. This study aims to investigate an effective and economical bake-out implementation strategy via experimentation and computational fluid dynamics analysis. The results showed weak direct correlation between the heating energy consumption and the amount of pollutants emitted. The study also highlights the passive option of installing sorptive building materials for improving IAQ economically.

scholarly journals The Improvement of Indoor Air Quality in Residential Buildings in Dubai, UAE

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 250
Author(s):  
Chuloh Jung ◽  
Jihad Awad
Keyword(s):  
Computer Simulation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Building Materials ◽  
Field Survey ◽  
Residential Buildings ◽  
Radon Gas ◽  
Volatile Organic ◽  
Residential Projects

Due to unprecedented urbanization, UAE had built many new residential projects with poor choices of material and ventilation. This social phenomenon is leading UAE to Sick Building Syndrome (SBS) faster than any other countries. The Dubai Municipality regulates the indoor air quality with strict stipulation, but the detailed regulations are still insufficient. The objective of this paper is to measure the indoor air quality of new residential projects in Dubai to suggest the improvement of the regulations for indoor air quality. As a methodology, a field survey was conducted to investigate the status of indoor air pollution in residential buildings. Based on the field survey data, lab experiments for building materials were conducted and a computer simulation on radon gas was conducted. The result had shown that radon gas was mainly detected in new townhouses and labor camp houses, and its concentration was found to exceed the standard. Volatile organic solvents (VOCs) and formaldehyde (CH2O) were mainly detected in showhouses and new townhouses, and the concentration distribution was about 10 times higher than that of outdoors. It was proven that emission concentration of radon gas from various building materials were detected, and the order was red clay, gypsum board, and concrete. Volatile organic solvents (VOCs) are mainly detected in oil paints and PVC floor and the radiation amount of all pollutants increased with temperature increase. In computer simulation, it was found that a new townhouse needs a grace period from 20 days to 6 months to lower the radon gas concentration by 2 pCi/L. This study will serve as a basic data to establish more detailed regulation for the building materials and improve the IAQ standards in Dubai.

scholarly journals Crushed Bricks: Demolition Waste as a Sustainable Raw Material for Geopolymers

2021 ◽  
Vol 13 (14) ◽  
pp. 7572
Author(s):  
Gigliola D’Angelo ◽  
Marina Fumo ◽  
Mercedes del Rio Merino ◽  
Ilaria Capasso ◽  
Assunta Campanile ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Building Materials ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Construction Material ◽  
Raw Material ◽  
The European Union ◽  
Total Energy Consumption ◽  
Demolition Waste ◽  
Crushed Brick

Demolition activity plays an important role in the total energy consumption of the construction industry in the European Union. The indiscriminate use of non-renewable raw materials, energy consumption, and unsustainable design has led to a redefinition of the criteria to ensure environmental protection. This article introduces an experimental plan that determines the viability of a new type of construction material, obtained from crushed brick waste, to be introduced into the construction market. The potential of crushed brick waste as a raw material in the production of building precast products, obtained by curing a geopolymeric blend at 60 °C for 3 days, has been exploited. Geopolymers represent an important alternative in reducing emissions and energy consumption, whilst, at the same time, achieving a considerable mechanical performance. The results obtained from this study show that the geopolymers produced from crushed brick were characterized by good properties in terms of open porosity, water absorption, mechanical strength, and surface resistance values when compared to building materials produced using traditional technologies.

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