Hot Regions Research Articles

Dipole Response of Mesoscale Eddy Formation to Monsoon Transition in the Southeast Tropical Indian Ocean

AbstractThe Southeast Tropical Indian Ocean (SETIO), dominated by the Indian Ocean monsoon, is an important source region for strong mesoscale eddies. To date, the impacts of the Indian Ocean monsoon on mesoscale eddies have not been clarified. Here we report on the dipole response of mesoscale eddy formation to monsoon transition in the SETIO, using satellite and reanalysis data sets. During the summer monsoon season, anticyclonic eddies are mainly concentrated north of 12°S, while cyclonic eddies are south of 12°S. This situation reverses during the winter monsoon season. We attribute this dipole feature to the oceanic perturbations and current shear during the different monsoon periods. A geographical boundary along 12°S aligns with meridional changes in eddy potential energy, which delineates the generation and direction of the newly‐formed eddies. The hot spot region, rich in eddy energy properties, tends to promote eddy formation and endurance during the monsoon periods.

Constructed Wetlands for Municipal Solid Waste Landfill Leachate Treatment with Different Macrophytes in Hot Cimate Regions: A Review

Constructed wetland is a natural, economical and environment friendly option for leachate treatment. The aquatic plants and microorganisms are the main players for the treatment of leachate and are conspicuous favoring feature for any wetland due to their contaminant treatment efficiency. There are several other features which limit or enhance the performance of wetlands. Temperature is one of the factors which influence the performance of any wetland and can improve overall efficiency of the constructed wetland. Deep study of oxygen function reveals that accumulation of oxygen to the liquid or soil of the wetland either by photosynthesis or direct from atmosphere. Organic mailer and nitrification process made possible by transfer of oxygen to rhizosphere through macrophytes and macrophytes grow well in growing season in the presence of sunlight and temperature. The argument is well supported through facts revealed by scientific observations. The natural process of photosynthesis only occurs in the presence of sunlight. Hence main performance of macrophytes depends upon their biomass production and fixation of oxygen to the rhizosphere in growing season, which ultimately enhances the efficiency of wetlands for contaminant removal. This review is to establish the fact that Typha latifolia, Phragmites australis and Scripus Validus are main hydrophytes depict best results in biogeochemical process for contaminant removal from wetlands in hot season except for the Total Suspended Solid (TSS) which does not show considerable difference due to the climate. This fact reveals that the macrophytes are more productive in the warm climate in comparison to cold one. The Typha latifolia, Phragmites australis and Scripus validus are the most common species of macrophytes which are very much affective in contamination removal process especially in temperate or tropical region where climate is above 30oC. The available data of different research papers establishes the fact that wetlands are the low-cost, eco-friendly and efficient solution for majority of contaminants removal. It has also been established that the Tropical and temperate regions enhance efficiency of all parameters up to 10% due to higher temperature.

Digital economy's role in shaping carbon emissions in the construction field: Insights from Chinese cities

Achieving net-zero greenhouse gas emissions in the construction sector is essential to sustainable development policy. Previous studies have ignored the impact of the digital economy on carbon emissions in the construction industry. Using relevant city-level data from China from 2011 to 2021 and employing ArcGIS and Stata software, this study examines the current status of carbon emissions from the construction industry and investigates the impact of the digital economy on these emissions. The findings reveal that (1) from 2011 to 2021, carbon emissions of the construction industry have a pattern of decreasing-increasing-decreasing-increasing across the country. There is an increasing concentration of areas with high and relatively high carbon discharges in Heilongjiang, Jilin, Ningxia, Inner Mongolia, Shanxi, Guangxi, and Guizhou. (2) The standard deviation ellipse indicates the core area of carbon emissions in China's construction industry is moving northeast and becoming more decentralized. (3) Through a series of robustness tests, the digital economy has been proven to effectively reduce carbon emissions from the construction sector in municipal areas. (4) In severely cold regions, mild regions, and high-population-density cities, the digital economy reduces building sector's carbon output. However, it stimulates carbon emissions in the hot summer and cold winter regions. (5) Mechanism tests show that the digital economy reduces China's urban construction carbon emissions by fostering technological progress and green innovation. Urban resilience further strengthens the contribution of the digital economy to reducing carbon discharges in the urban construction sector of China. This article presents empirical evidence demonstrating how the digital economy empowers the construction industry to curtail emissions.

Modeling and performance analysis of a 5MW grid-connected photovoltaic power plant in the hot region of in Salah, Algeria

Modeling and performance analysis of a 5MW grid-connected photovoltaic power plant in the hot region of in Salah, Algeria

Optimizing Split-reduced drip fertigation schemes of Arabica coffee based on soil microcosms, bean yield, quality and flavor in dry-hot region of southwest China

As a characteristic cash crop in Yunnan Province, China, Arabica coffee ranks first in the country in terms of cultivation area and production, but has always suffered from poor soil nutrient management and a lack of scientific basis for fertilization. It is not clear how to improve the soil microecological environment using split-reduced drip fertigation at different reproductive stages of Arabica coffee to improve bean yield and quality. Therefore, a two-year (2020–2022) field experiment was conducted on 5-year-old Arabica coffee trees in a dry-hot region with five split-drip fertigation patterns, F450, F600, F750, F900 and F1050. Using the local conventional fertilization (Fertilizer of 900 kg ha−1 year−1 only in berry expansion, and no fertilization in early flowering and berry ripening) as the control (CK). The effects of different fertilization modes on soil microecological environment, bean yield, nutritional quality and characteristic flavor were studied, and a comprehensive benefit evaluation model to assess bean yield and nutritional quality under different fertilization modes was established. The results showed that F900 significantly increased soil nitrate nitrogen, available phosphorus, available potassium, microbial population and enzyme activities at early flowering and berry ripening stages compared to CK, while F900 reduced soil nitrate nitrogen, available phosphorus and available potassium but increased soil enzyme activity and microbial population at the berry expansion stage. Compared with CK, F450 decreased bean yield, caffeine and chlorogenic acid content by 31.83 %, 23.73 % and 13.48 %, respectively, while F750 increased two-year average yield, raw bean fat, caffeine and chlorogenic acid content by 20.52 %, 12.37 %, 5.48 % and 11.17 %, respectively. The two-year average yield of F600 showed less difference from CK. Marginal yield was positive and then negative with increasing fertilizer application. Dry bean yield decreased at a total fertilizer application of 900 kg ha−1 year−1. Correlation analyses showed a positive correlation between soil microbial environment and nutrient quality of coffee beans, while different correlations were found between nutrients and volatiles at dark and medium roasting levels. Cluster analysis revealed that the relative contents of aldehydes, alcohols, phenols, pyridines, and pyrroles were higher under dark roasted condition, while the relative contents of ketones, esters, acids, and pyrazines were higher under medium roasted condition. Based on the Entropy weight-TOPSIS method, F750 had the highest combined benefits in terms of yield increase and quality improvement, and the total fertilizer application decreased by 16.67 % compared to CK, thus F750 treatment was the most suitable split-drip fertigation strategy for Arabica coffee in the dry-hot region of Yunnan. This study provided a reference for drip fertigation systems of Arabica coffee in dry and hot regions.

Optimal design of multilayer optical thin film structure for smart energy saving applications using needle optimization approach

In this work, a novel design of a one dimensional photonic crystal (1D PC) is investigated. The 1DPC structure is composed of alternating layers of tantalum pentoxide (Ta2O5) and silicon dioxide (Sio2). The proposed 1D PC structure is designed to act as short wave pass (SWP) edge filter that selectively passes light of short wavelengths, while the infrared light is blocked. In this study, Essential Macleod software is used to create the optimal design with the computational support of the needle synthesis technique. By varying the incidence angle of the mean polarized light mode, we can determine the features of the optimal SWP edge filter design, which leads to an important application for this filter. It can shed light on the filter’s suitability as a smart energy saving window coating for hot climate regions. The study includes different hot regions in Saudi Arabia such as Mecca, Riyadh, Dammam, Arar and Alaqiq. They were used as case studies in this research. According to the study of the optimal design of SWP edge filter applied in Mecca, Riyadh, Dammam, Arar and Alaqiq provinces, the light transmittance in the visible region is more than 99% during the summer solstice and more than 96% during the winter solstice. The photonic band gab (PBG) is almost constant during the summer solstice without shifting or decreasing in size whereas in the winter solstice, the PBG shifts toward the short wavelengths and decreases in size by increasing the angle of incidence. This allows an amount of solar energy to enter in winter. Riyadh, Dammam, and Arar provinces experienced a significant increase in solar energy during the winter solstice, more than Mecca and Alaqiq provinces.

Enhancing Building Thermal Inertia: Impact of Surface-to-Volume Ratio on Multi-Layered PCM-Integrated Brick Walls

Abstract In this paper, a numerical study is conducted to investigate the effect of using Phase Change Materials (PCMs) in building bricks to improve the thermal inertia of buildings in hot and dry regions. A numerical model is developed to simulate the heat transfer in a brick with cylindrical holes filled with PCM. The effects of the number, type, and arrangement of PCMs on the thermal performance of the brick are investigated. The results show that the use of PCMs can significantly reduce the heat flux through the brick. The optimal number of PCMs is found to be three layers. The optimal type of PCM for the first layer is n-Eicosane, for the second layer is Paraffin Wax, and for the third layer is n-Octadecane. The enhanced brick configuration, with specific PCM arrangements, reduced total heat flux by up to 71.53% in the simulation period, compared to a brick without PCM.

Studying effect of temperature on the efficiency of solar cells through the interpolation method

The objective of this paper is to present a comparative study between the traditional least squares method 'LSM' and the new method of "Polynomial Interpolation at Different Orders" for extracting the electrical parameters of a silicon solar cell. The focus is on the advantages and disadvantages of each approach. The results indicate that fourth-order interpolation yields the best results, but it is challenging to implement because the J-V function is neither linear nor transcendental. Therefore, we opted for the first-order Piecewise Linear Interpolation 'PLI' in the range where the J-V characteristic is nearly flat, i.e., the interval where the voltage varies from 0 to Vmax. By utilizing the first-order derivative of the function f(J, V) with two variables and MATLAB fzero function, we were able to determine the five critical parameters for our solar cell: the series resistance RS, the shunt resistance RSh, the light-generated current density Jph, the reverse saturation current density J0, and the ideality factor n. We used the Bland-Altman technique to evaluate the comparability between the two methods. The results obtained using this technique show that all the data points lie within the confidence interval. This indicates that the piecewise interpolation method provides J-V characteristic values very similar to those found by the LSM method. The strength of the new method lies in its speed, practicality, and the fact that it does not require initial values for the solar cell parameters. Additionally, it avoids the need to determine the variation intervals for each parameter and the use of complex functions such as the Lambert W function, which is necessary in the LSM method. By applying this method, we examined how the electrical parameters behave when the temperature varies from a cold region (0 °C) to a hot region (50 °C). The analysis of the results obtained by both scientific methods, namely the LSM method and polynomial interpolation, reveals a decrease in cell efficiency from 19.63 to 13.73 %. Similarly, the open-circuit voltage decreases from 0.62 to 0.524 V, and the ideality factor also decreases from 2.2 to 1.54. The current decreases from 39.50 to 34.30 mA/cm2 as the temperature increases from 0 °C to 30 °C, then stabilizes at 34.30 mA/cm2 for temperatures ranging from 30 °C to 50 °C.

Empirical heat transfer correlations of high-pressure transcritical fluids at low Reynolds numbers

Empirical heat transfer correlations serve as indispensable tools for predicting and optimizing the thermal performance of a wide range of engineering devices, like for example in energy conversion and propulsion applications. Although a remarkable number of correlations exist for systems at low (atmospheric) pressures, accurately quantifying heat transfer under high-pressure transcritical conditions poses a notable challenge, especially at low Reynolds numbers due to the scarcity of correlations available in the literature. This difficulty has prompted the widespread use of general empirical correlations, which are inadequate for such flow conditions, and hold significant implications, for instance, in fields like microfluidics technology. In this regard, the aim of this study is to develop novel heat transfer correlations tailored for high-pressure transcritical fluids at relatively low Reynolds numbers. These correlations are derived from a dataset of 18 direct numerical simulations of carbon dioxide confined between differentially heated walls, which induce a transcritical trajectory through the pseudo-boiling region. The correlations are developed for both the cold liquid-like and hot gas-like regions, resulting in a total of 6 correlations that encompass the laminar, transitional, and turbulent flow regimes. In particular, as a function of Reynolds, Prandtl, Eckert and Mach numbers, the proposed empirical correlations provide accurate estimations with relative errors below 8%, which significantly surpass existing literature correlations.

Optimizing Groundnut (Arachis hypogaea L.) Yields: An Effect of Sowing Dates and Planting Densities in India Hot Arid Regions Under a Changing Climate

Optimizing Groundnut (Arachis hypogaea L.) Yields: An Effect of Sowing Dates and Planting Densities in India Hot Arid Regions Under a Changing Climate

Subjective evaluation of thermal comfort of tropically acclimatized subjects in air conditioned, naturally ventilated and radiant cooling environments

The thermal sensation of people is subjective. It depends on the external climatic condition and thermal history of a person. Thermal comfort standards suggest a narrow temperature range to assert an environment as comfortable or otherwise. It is important to evaluate people’s thermal perception in different climatic regions and set comfort limits based on their thermal perception. This study evaluates the thermal perception of subjects in hot and humid climatic regions at higher indoor temperatures and air velocities. Three different thermal environments chosen for the study are air conditioned (AC), naturally ventilated (NV), and radiant cooling (RC) thermal environments. The study shows that more than 80% of subjects voted as comfortable in AC and RC thermal environments for the measured Top and va range of 25.3 – 28.4℃/0.1 – 0.3m/s and 25.9 – 29.1℃/0.1 – 0.9m/s respectively. The findings gathered from the study in NV environment indicate that 68% of subjects opt for the use of table fans over ceiling fans. The subjects' free control of air movement improves their thermal sensation over no control of air movement, indicating that they prefer table fans and free control of air movement. In AC, NV, and RC thermal environments, humidity and air quality remain uncontrolled. In AC and RC thermal environments, less than 20% of subjects voted unacceptable for the humidity sensation and Perceived air quality (PAQ) scales in nearly all the studied experimental conditions. In NV thermal environment, the percentage of subjects voting dissatisfied on the humidity sensation scale and PAQ scale is 30-52% and 26-37%, respectively. This outcome shows that a thermally comfortable environment with air movement improves subjects' humidity sensation and PAQ even when humidity and air quality are unaltered. The study points out that air velocity played a vital role in influencing the thermal sensation, humidity sensation and perceived air quality of subjects in the three studied thermal environments. Further the study shows that with free control of air movement will significantly aid in rising the comfort temperature band of tropically acclimatized subjects. Practical application The study shows the variation in limits of thermal comfort indices such as operative temperature and air velocity for tropically acclimatized subjects in three thermal environments. The same group of subjects participated in the subject study conducted in air conditioned, naturally ventilated and radiant cooling thermal environments. The outcomes indicate that subjects are comfortable at higher indoor temperature and air velocity. Further the outcomes showed that the humidity and air quality sensation of subjects is influenced by the subjects’ thermal sensation and air velocity.

Carbon emissions path of public buildings based on LEAP model in Changsha city (China)

China is currently the world's top carbon emitter due to the acceleration of urbanization, the rapid growth of energy consumption and the rise in carbon emissions, with the construction industry leading the three energy sectors in terms of emission reduction potential. Among the various sectors, the construction industry holds immense potential for emission reduction, with public buildings playing a crucial role. In China, the expansion of public building spaces is closely linked to the pace of urbanization and contributes to a rising share of total building area. Public buildings, characterized by high energy usage, offer a great opportunity for energy conservation and emission reduction. Changsha is experiencing rapid growth and change, and the city is becoming more industrialized and urbanized, which leads to a prominent contradiction between energy supply and demand. There is also great potential for energy conservation and emission reduction in public buildings. Additionally, Changsha is an important node city in the Yangtze River urban agglomeration and the middle reaches of the Yangtze River Economic Belt. It is a typical area that has hot summer and cold winter, thus Changsha is selected as the research case to examine the carbon emission path of public buildings. The primary influencing factors of carbon emissions of public buildings in Changsha City are determined by using the LMDI factor decomposition method addition model. The scenario analysis method is adopted to set the two energy consumption forecast scenarios, which are the baseline scenario and the green scenario. Based on LEAP model and GREAT framework structure, the LEAP prediction model is constructed to predict the carbon emissions of public buildings in Changsha City from 2021 to 2035. The Baseline scenario indicates that while carbon emissions from public buildings in Changsha continue to rise, they are expected to decline starting in 2030. The peak carbon emission of 34.279 million tons of CO2 is predicted for 2032. In contrast, the Green scenario reveals a significantly slower growth rate in carbon emissions from public buildings, with the peak carbon emission projected to reach 27.054 million tons in 2030. This aligns with China's national goal. The findings of this study support the accuracy of the long-term prediction of the model, and offer recommendations for energy conservation and emission reduction in Changsha. This study also provides an example and certain guidance for other provinces and cities that have similar development models and climate conditions. Pertinent development strategies serve as a point of reference for other typical hot summer and cold winter regions.

Reuse of waste rockwool for improving the performance of LC3-based mortars made with natural and recycled aggregates for sustainable building solutions

The objective of this study is to investigate the effect of waste rockwool (RW) addition on the thermo-physical, mechanical, and fire resistance properties of limestone calcined clay cement (LC3)-based mortars. LC3 binder has been produced by replacing 60 wt% of OPC with limestone (LS) powder and metakaolin (MK) at a percentage of LS to MK of 1:2 (wt%). Waste RW was added at various ratios of 1, 3 and 5 % (by weight of binder) into two types of LC3-based mortars made with natural sand (NS) and ferrochrome waste slag (FCS) aggregates with a binder-to-aggregate vol% of 1:3. Upon the addition of 5 wt% of waste RW, significant enhancements of about 19 % and 21 % were obtained for the compressive strength of NS and FCS mortars, respectively, and attributed to the improved physical packing. After exposure to standard fire for 1 h with a maximum applied temperature of 945 °C, residual strengths of about 57.5 % and 63.8 % have been maintained by the sand and FCS-blended LC3 mortars, respectively. Generally, the incorporation of RW led to a slight increase in the thermal conductivity of both types of mortars; however, the FCS-blended LC3 mortar possessed relatively higher increment rates as compared with the sand mortar, which is helpful in improving the thermal performance in hot climate regions. Remarkable improvements in the microstructure characteristics in terms of compactness, uniformity, and interfacial transition zone (ITZ) tightness were attained by RW addition. Lifecycle assessment (LCA) results demonstrated that about 38–45 % lower carbon emission is associated with the designed LC3-based mortars than the conventional OPC mortar.

Design an energy storage system for a 1 MW photovoltaic powerplant based on compressed-gas-refrigeration for buildings cooling and ice production

An energy storage system was designed for a 1 (MW) photovoltaic solar power plant. This power plant is located in a university campus in the hot desert region, which requires continuous cooling of its buildings consists of a large number of classrooms. Due to the desert nature of the region, it was not possible to use conventional energy storage systems based on pumped-hydro; because in considered climate, it is not possible to provide a large volume of water and compensate for the evaporated water. Therefore, an energy storage system based on compressed gas refrigeration was used. The effect of system parameters including the maximum pressure on its performance including COP, total space can be cooled, ice making capacity and also the required volume for high-pressure vessel was studied. The effect of using different gases including air, nitrogen, ammonia, carbon dioxide and argon as the working fluid was studied. Also, the effect of the mixture of nitrogen and carbon dioxide and different molar percentages of them on the performance of the system was studied. The results showed that the designed energy storage system can well supply the cooling load of the university building where the solar power plant is located.

Spatial Differentiation and Influencing Factors of Traditional Villages in Fujian, China: A Watershed Perspective

Watersheds provide a spatial framework for tightly coupling human activities and the natural environment. Investigating the spatial distribution patterns of traditional villages within watersheds is crucial for comprehending their origins and advancing conservation and development efforts. This study employs methods such as the nearest neighbor index, kernel density estimation, spatial auto-correlation analysis, stepwise regression, and geographically weighted regression to explore the watershed characteristics and influential factors governing the spatial differentiation of traditional villages in Fujian Province. The findings indicate that traditional villages in Fujian exhibit an overall clustered distribution within the watershed space, with a tendency to cluster along basin boundaries, primarily concentrated in three hot spot regions. In the remaining small watersheds, the distribution is more balanced. Traditional villages are predominantly located near low-order streams, displaying a distribution pattern along tributaries, while in the Huotongxi river basin, they are more evenly distributed near second-, third-, and fourth-order streams. Relief, annual average temperature, annual average precipitation, arable land, per capita GDP, distance to county-level or higher-grade cities, and the concentration of cultural heritage preservation units are the primary factors affecting the spatial differentiation of traditional villages within watersheds, exhibiting significant spatial heterogeneity. Finally, this study proposes recommendations for the cluster protection and development of traditional villages in watersheds, addressing spatial, cultural, landscape, industrial, and governance aspects.

Global selection appraisal study for heat pump system of electric vehicle based on energetic, economic, and environmental analysis

The development of electric vehicles (EVs) exhibits rapid and remarkable progress nowadays, serving as a crucial route to accomplish the target of mitigating greenhouse gas emissions. As an integral part of the thermal management system oriented toward electric vehicles, the heat pump air conditioning system for electric vehicles is the result of a comprehensive choice that trades off the cooling and heating performance, environmental performance and economic cost. Particularly, different regions around the world suffer varying cooling and heating challenges due to the complicated climatic characteristics. Thus the most suitable refrigerant and system cycle structure may differ. This paper focuses on evaluating both the refrigerants and cycle structures to screen the most suitable choice. According to the climate conditions of different cities, the annual energy consumption, life cycle climate performance, and economic cost of the basic system (Base), two-stage compression system (TSC,IC), and vapor injection (VI) system with CO2, R134a, and R1234yf refrigerants respectively, are quantitatively analyzed and evaluated. Subsequently, through comparative analysis, a comprehensive selection map for heat pump systems in electric vehicles worldwide is developed and the most suitable heat pump air conditioning system for each cites is determined. The results can provide a selection reference and decision-making for the air conditioning system of electric vehicles from regional considerations. It was found that the CO2 HPACVI was recommended for cold regions to meet both environmental and economic requirements. In warm region, the R1234yf HPACBase system was recommended to be used. For regions transitioning from cold to warm climates, the R1234yf HPACVI system was suggested. In hot region, the R1234yf AC system was recommended.

Improve Thermal Performance and comfortable Design of Public Library Located in Middle Eastern Regions Facing Drastic Climate Change

Abstract Public libraries have important functions as information hubs and cultural institutions, drawing a variety of user groups. As user experience, contentment and general productivity are greatly improved by the thermal comfort of interior spaces, libraries are committed to providing suitable temperatures for both human thermal comfort and for preserving books. The standards for the handling and care of library resources established by the International Federation of Library Associations in 1999 specify the need for constant temperature and humidity in the safekeeping of library items. The recommended temperature range for sedentary activities including reading, is 20-22 °C, comfortable for people in cold regions. Hot climates prevalent in Middle Eastern nations, challenges achieving thermal comfort for library visitors. According to ASHRAE Standard 55 (2020), the most comfortable temperature in hot and humid environments is 24°C, +/- 1°C. Three methods were used in this study. First, this study gives an overview of the history of libraries in Middle East regions, and analyses the development of design elements in controlling temperatures and book preservation of this region’s libraries before and after air conditioning. Second, comparative case studies of Qatar National Library and King Fahad Library showcase differing thermal comfort approaches. Third, interviews with the two libraries users and administrators. Interior temperature, design choice and clothing preferences of patrons are examined in relation to thermal comfort in libraries. The results show that public libraries in hot regions often struggle to provide the temperatures needed to give user comfort and preserve books. This study identifies factors and design approaches to improve the thermal comfort and sustainability of Middle Eastern libraries, intersecting quantitative factors (air temperature and flow) with qualitative factors (colour, material finish and architectural and interior design). It exposes tensions between these approaches to book conservation and user comfort, to develop guidelines for effective design strategies in libraries.

Validation of the thermo-chemical approach to modelling of CO2 conversion in sub-atmospheric pressure microwave gas discharges

The CO 2→ CO + 12 O2 conversion experiment [D’Isa et al 2020 Plasma Sources Sci. Technol. 29 105009] has been compared with thermo-chemical calculations. The experiment is a 2.45 GHz plasma torch with a straight channel in the effluent. The 1.5D model of the CO2/CO/O2/O/C mixture without turbulent transport has been applied with plasma acting only as a prescribed heat source. The parameter range covered is the specific energy input (SEI) 0.3–5 eV/molecule at pressure p = 0.9 bar, and SEI = 0.6–2 eV/molecule at p = 0.5, 0.2 bar. The calculated conversion χ is always close to the experimental values. At the same time, the calculated temperatures T deviate significantly from the experiment, especially for p = 0.2 bar. The calculated T were also found to be sensitive with respect to the uncertain model parameters, but χ is not sensitive. The net conversion in the model is driven to a large extent by the radial diffusion of CO and O from the hot core towards the wall and steep radial temperature gradients. The main factor that reduces the energy efficiency is the re-oxidation of CO at the edge of the hot plasma region and downstream. The 1.5D approximation applied has the principle limitation that the impact of a realistic bulk flow field on the chemical process cannot be studied. Hence, the results must be considered preliminary and have to be confirmed with a more elaborate and accurate model of the vortex-stabilized flow inside the reactor.

Architectural Design Recommendations Based on Bioclimatic Features Using Climate Consultant and Mahony Tables Strategies

Abstract The aim of this research is to provide bioclimatic design suggestions to improve the thermal comfort of people in hot and humid climates according to the BWh (hot desert climate) Köppen climate classification. The city of Minia is considered one of Egypt’s hot desert regions. This study considered two main variables to achieve thermal comfort according to air velocity and temperature. To select the best bioclimatic design tactic, the findings are reviewed and plotted on the Climate Consultant (CC) Bioclimatic Chart and the Mahoney Table (MT). The proposed procedures are presented as figures relating to the approaches and are examined independently. We conclude that specific bioclimatic design strategies have been applied through the extensive study presented in this paper for Minia City, which can be exported to other regions with comparable climates. These strategies are practically and effectively considered functional architectural approaches that can improve thermal comfort for people. The two tools CC and MT are compared based on 27 recommended strategies that can be achieved according to the bioclimatic parameters that were studied. They agreed with 30% as good natural ventilation, passive solar heating with a high percentage that reached 10% for each. Where there is a difference of 20 recommendations to 70%, this represents other factors or recommendations such as shading with which it is proposed in MT as well as other parameters.

Chinese raw vermiculite: A potential additive for improving the thermal properties of calcium sulfoaluminate cement-blended mortars for applications in hot regions

Reducing the thermal conductivity (TC) of a cementitious building material can help to slow the rate at which it heats and cools. The present project aims to develop a new construction material with low TC for use in hot regions. The construction material is produced by blending Chinese raw vermiculite (CRV) with calcium sulfoaluminate (CSA) cement in mortar. CSA mortar specimens were cast and tested for a variety of properties, including dry density (σ), void content, ultrasonic pulse velocity (UPV), thermogravimetric variations, microstructure, TC, thermal diffusivity, and specific heat capacity. CSA mortars mixed with CRV had improved workability and σ. However, compared to plain CSA mortar, the compressive strength of the CSA mortars incorporating 60 % and 100 % CRV was reduced by 10 % and 24 %, respectively. This reduction in strength is still acceptable for non-structural applications, and the decrease in strength remains close to that of CSA mortars without CRV. The TC of CSA mortar with 0 % fine aggregate replacement was 1.99 ± 0.17 W/mK, which is 95.07 % higher than when 100 % CRV was used as the fine aggregate replacement. The addition of CRV slows CSA mortar heating by 20 %. The findings confirms CRV's potential as an eco-friendly, energy-efficient construction material.