scholarly journals Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature

2021 ◽  
pp. 1-15
Author(s):  
Mostafa Kazemi ◽  
Luc Courard
Keyword(s):  
Temperature Distribution ◽  
Green Roof ◽  
Weather Conditions ◽  
Drainage Layer ◽  
Ceiling Temperature ◽  
Seasonal Weather

scholarly journals Heat Transfer Measurement within Green Roof with Incinerated Municipal Solid Waste Aggregates

2021 ◽  
Vol 13 (13) ◽  
pp. 7115
Author(s):  
Mostafa Kazemi ◽  
Luc Courard ◽  
Julien Hubert
Keyword(s):  
Heat Transfer ◽  
Heat Resistance ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Green Roof ◽  
Insulation Material ◽  
Drainage Layer ◽  
Roof System ◽  
Substrate Layer ◽  
Significant Difference

A green roof is composed of a substrate and drainage layers which are fixed on insulation material and roof structure. The global heat resistance (Rc) within a green roof is affected by the humidity content of the substrate layer in which the coarse recycled materials can be used. Moreover, the utilization of recycled coarse aggregates such as incinerated municipal solid waste aggregate (IMSWA) for the drainage layer would be a promising solution, increasing the recycling of secondary resources and saving natural resources. Therefore, this paper aims to investigate the heat transfer across green roof systems with a drainage layer of IMSWA and a substrate layer including recycled tiles and bricks in wet and dry states according to ISO-conversion method. Based on the results, water easily flows through the IMSWAs with a size of 7 mm. Meanwhile, the Rc-value of the green roof system with the dry substrate (1.26 m2 K/W) was 1.7 times more than that of the green roof system with the unsaturated substrate (0.735 m2 K/W). This means that the presence of air-spaces in the dry substrate provided more heat resistance, positively contributing to heat transfer decrease, which is also dependent on the drainage effect of IMSWA. In addition, the Rc-value of the dry substrate layer was about twice that of IMSWA as the drainage layer. No significant difference was observed between the Rc-values of the unsaturated substrate layer and the IMSWA layer.

scholarly journals The influence of a green roof drainage layer on retention capacity and leakage quality

2018 ◽  
Vol 77 (12) ◽  
pp. 2886-2895 ◽  
Author(s):  
Anna Baryła ◽  
Agnieszka Karczmarczyk ◽  
Andrzej Brandyk ◽  
Agnieszka Bus
Keyword(s):  
Water Quality ◽  
Green Roof ◽  
Life Sciences ◽  
Meteorological Station ◽  
Runoff Water ◽  
Retention Capacity ◽  
Drainage Layer ◽  
Second Year ◽  
Substrate Moisture ◽  
Leachate Quality

Abstract The aim of the research was to determine the influence of the substrate and different drainage materials on retention capacity and runoff water quality from three green roof containers. Phosphates were chosen as the water quality indicator based on their potential adverse impact on water quality in urban rainwater collectors. The field experiment was conducted at the Warsaw University of Life Sciences Water Center meteorological station in years 2013–2015. In terms of precipitation, the monitoring period covered a wet (+147.1 mm), average (+42.7 mm) and dry (− 66.3 mm) year. Leakage from the containers was recorded when the substrate moisture exceeded 20% and precipitation exceeded 3.5 mm/d for washed gravel, or 5.0 mm/d for a polypropylene mat and expanded clay. Phosphates were observed in leachates from all containers, with higher values observed in the second year of monitoring. As the result of this study, it can be concluded that the polypropylene mat and aggregates create different conditions for the formation of the leachate, in both volumes and its chemistry. The drainage layer made from a polypropylene mat is the most effective in terms of rainwater retention capacity and the resulting leachate quality.

scholarly journals An Experimental Investigation of the External Wind Effects on the Ceiling Temperature Distribution of Fire-Induced Thermal Flow in a Corridor Connected to a Compartment

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1826
Author(s):  
Bei Cao ◽  
Xiaodong Zhou ◽  
Yubiao Huang ◽  
Yuan Zheng ◽  
Kai Ye ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Temperature Distribution ◽  
Wind Velocity ◽  
Shielding Effect ◽  
Temperature Profiles ◽  
Building Structures ◽  
Thermal Flow ◽  
Ceiling Temperature ◽  
Higher Temperature

Fire-induced thermal flow is the greatest threat to trapped people and the heat-resistant quality of building structures. This paper presents an experimental investigation of the effects of external wind on the ceiling temperature distribution of fire-induced thermal flow in a one-sixth scale corridor connected to a compartment. In the experiments, the fire source was placed in the compartment with hot thermal flow spilled into the connected corridor. The heat release rate (HRR) was changed from 10 to 20 kW and the external wind velocity was changed from 0 to 2.09 m/s. The ends of the corridor could be adjusted to be fully or partially open to the environment with dam-boards arranged at the ends of the corridor. An effective corridor HRR, Qcorridor, was defined to account for the amount of the spilled plume into the corridor. Results show that the temperature under the ceiling changed in a non-monotonic way with wind velocity: it first increased and then decreased with wind velocity. It was revealed that the dam-boards at the corridor opening had an evidently shielding effect, leading to higher temperature compared to the fully open environment. Finally, uniform correlations are proposed for predicting the attenuation law of ceiling temperature profiles in corridors for different wind conditions.

scholarly journals A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1411 ◽  
Author(s):  
Peng Zhao ◽  
Zhongyuan Yuan ◽  
Yanping Yuan ◽  
Nanyang Yu ◽  
Tao Yu
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Empirical Equation ◽  
Ventilation System ◽  
Volumetric Flow Rate ◽  
Subway Tunnel ◽  
Smoke Control ◽  
Long Distance ◽  
Tunnel Fire ◽  
Ceiling Temperature

Smoke control is a crucial issue in a long-distance subway tunnel fire, and a two-point extraction ventilation system is an effective way to solve this problem, due to the characteristics of controlling the smoke in a limited area and removing high-temperature and toxic smoke in time. In this study, the ceiling temperature distribution and the critical exhaust volumetric flow rate to control the smoke in the zone between two extraction vents were investigated in a long-distance subway tunnel fire with a two-point extraction ventilation system. Experiments were carried out in a 1/20 reduced-scale tunnel model based on Froude modeling. Factors, including the heat release rate (HRR), the extraction vent length, the internal distance between two extraction vents and exhaust volumetric flow rate, were studied. Smoke temperature below the ceiling, exhaust volumetric flow rate and smoke spreading configurations were measured. The ceiling temperature distribution was analyzed. Meanwhile, an empirical equation was developed to predict the critical exhaust volumetric flow rate based on the one-dimensional theory, experimental phenomenon and the analysis of forces acting at the smoke underneath the extraction vent. The coefficients in the empirical equation were determined by experimental data. Compared with the experimental results, the developed empirical equation can predict the critical exhaust volumetric flow rate well. Research outcomes in this study will be beneficial to the design and application of two-point extraction ventilation system for a long-distance subway tunnel fire.

Observations of the ABL Structures over a Heterogeneous Land Surface during IHOP_2002

2007 ◽  
Vol 8 (2) ◽  
pp. 221-244 ◽  
Author(s):  
Song-Lak Kang ◽  
Kenneth J. Davis ◽  
Margaret LeMone
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Land Surface ◽  
Joint Probability ◽  
Surface Flux ◽  
Weather Conditions ◽  
Surface Heterogeneity ◽  
Small Scale ◽  
Mesoscale Circulations ◽  
Obukhov Length

Abstract This study analyzes data collected by aircraft and surface flux sites over a 60-km north–south-oriented aircraft track for five fair-weather days during the International H2O Project (IHOP_2002) to investigate the atmospheric boundary layer (ABL) structures over a heterogeneous land surface under different background weather conditions. The surface skin temperature distribution over the aircraft track in this case is mostly explained by the soil thermal properties and soil moisture, and corresponds to the observed ABL depths except one day having a weak surface temperature gradient and a weak capping inversion. For the other four days, the blending height of the surface heterogeneity likely exceeds the ABL depth and thus the ABL establishes equilibrium with local surface conditions. Among the four days, two days having relatively small Obukhov lengths are evaluated to show the background weather conditions under which small-scale surface heterogeneity can influence the entire ABL. In fact, on one of these two days, relatively small-scale features of the surface temperature distribution can be seen in the ABL depth distribution. On the two small Obukhov length days multiresolution spectra and joint probability distributions, which are applied to the data collected from repeated low-level aircraft passes, both imply the existence of surface-heterogeneity-generated mesoscale circulations on scales of 10 km or more. Also on these two small Obukhov length days, the vertical profiles of dimensionless variances of velocity, temperature, and moisture show large deviations from the similarity curves, which also imply the existence of mesoscale circulations.

scholarly journals The effects of population density and malnutrition on the dynamics of whooping cough

1998 ◽  
Vol 121 (2) ◽  
pp. 325-334 ◽  
Author(s):  
C. J. DUNCAN ◽  
S. R. DUNCAN ◽  
S. SCOTT
Keyword(s):  
Time Series ◽  
Population Density ◽  
Life Expectancy ◽  
Mathematical Modelling ◽  
19Th Century ◽  
Whooping Cough ◽  
Weather Conditions ◽  
Demographic Characteristics ◽  
The 19Th Century ◽  
Seasonal Weather

Liverpool, a seaport in NW England, suffered severely from lethal infectious diseases in the second half of the 19th century: the population was densely crowded and malnourished and life expectancy was low. Time-series analysis shows that the epidemics of whooping cough (i) had an interepidemic interval of 2·9 years, 1863–85, which lengthened to 3·4 years, 1885–1900 (ii) were strongly coherent with wheat prices (P<0·001) and (iii) also correlated with cycles of seasonal weather conditions. It is suggested from mathematical modelling that the epidemics in this compromised population were maintained (i.e. the system was driven) by an oscillation of malnutrition and by seasonal weather conditions. A model that incorporates both the dynamics of whooping cough and the demographic characteristics of the population is presented. It has been shown to replicate the dynamics of the epidemics and has been used to predict the changes with time of (i) the force of the infection and (ii) the proportion of those infected with whooping cough who died.

Application of Styrofoam in the Elements of Building Constructions

2015 ◽  
Vol 725-726 ◽  
pp. 396-402 ◽  
Author(s):  
Radinko Kostić ◽  
Viktor Pukhkal ◽  
Nikolay Vatin ◽  
Vera Murgul
Keyword(s):  
Temperature Distribution ◽  
Heat Flow ◽  
Weather Conditions ◽  
Building Structures ◽  
Exterior Wall ◽  
Saint Petersburg ◽  
Building Enclosure ◽  
Wall Panels ◽  
Building Elements ◽  
The Way

The article presents the possibilities for the contemporary application of Styrofoam in the elements of building structures. Having in mind that Styrofoam belongs to a group of highly flammable materials, 5 % of combustion retarder - so called "retardant" - needs to be added to the amount when produced for structural building elements. That kind of Styrofoam is called "self-extinguishing" contrary to "normal" that does not contain that substance. The Article also shows the way in which building elements are constructed (external and interfloor construction), made out of Styrofoam using "Plastbau" technology. A possibility to use exterior wall panels ‘Plastbau’ under weather conditions of Saint-Petersburg has been considered. Temperature distribution along a wall’s section as well as a heat flow going through a building enclosure ‘Plastbau’ have been also analyzed herein.

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