External Weather Conditions Research Articles

Experimental case study on the effect of the urban morphology on urban microclimate and outdoor thermal comfort

The present study aims at testing the influence of the urban morphology on the external weather conditions and the urban microclimate by treating quantitative aspects of the outdoor thermal comfort. This is based on a site investigation aims at studying the correlation between the geometry of the street, its orientation and the evolution of the physical variables: air temperature (Ta), Mean Radiant Temperature (MRT), Relative Humidity (RH), Wind speed (Ws). The measures were the subject of a campaign carried out in the urban fabric of the ksar of the red village in the wilaya of Biskra in Algeria. The objective is to define the most efficient urban geometry in term of summer thermal comfort by studying the real impacts of the urban form on the solar control and microclimatic conditions. The evaluation of the thermal comfort in these external spaces is carried out by analyzing physiologically equivalent temperature (PET) values calculated by Rayman Pro 2.1 software based on the measured microclimatic parameters.

Experimental case study on the effect of the urban morphology on urban microclimate and outdoor thermal comfort

The present study aims at testing the influence of the urban morphology on the external weather conditions and the urban microclimate by treating quantitative aspects of the outdoor thermal comfort. This is based on a site investigation aims at studying the correlation between the geometry of the street, its orientation and the evolution of the physical variables: air temperature (Ta), Mean Radiant Temperature (MRT), Relative Humidity (RH), Wind speed (Ws).The measures were the subject of a campaign carried out in the urban fabric of the ksar of the red village in the wilaya of Biskra in Algeria. The objective is to define the most efficient urban geometry in term of summer thermal comfort by studying the real impacts of the urban form on the solar control and microclimatic conditions. The evaluation of the thermal comfort in these external spaces is carried out by analyzing physiologically equivalent temperature (PET) values calculated by Rayman Pro 2.1 software based on the measured microclimatic parameters.

Measuring and mitigating overheating risk in solid wall dwellings retrofitted with internal wall insulation

Upgrading the thermal insulation of UK houses to improve wintertime energy efficiency raises concerns about potential summertime overheating risk. To address these concerns, experiments were conducted in a pair of thermally matched, solid walled houses, located in the UK. One of the pair was retrofitted with internal wall insulation, while the other remained uninsulated; both houses were monitored for four weeks during the summer of 2015. Operative temperatures in the living room and main bedroom were observed to be higher in the internally insulated house in comparison to the uninsulated house. The houses were again monitored for a further three weeks with a simple overheating mitigation strategy applied consisting of night ventilation and shading using internal blinds. The data were normalised for variations in external weather conditions using a linear regression model, with the exponentially-weighted outdoor running mean air temperature as the predictor variable of indoor operative temperature. The results showed that the mitigation strategy was effective at reducing the internal temperature in the internally insulated house to a level similar to that observed in the uninsulated house. The marginal increase in overheating risk should not be considered a barrier to the uptake of IWI in this type of house and location, at this time. Shading devices and secure noise attenuating vents for existing dwellings may be needed as part of a package of refurbishment in the future. It could become a requirement within the Building Regulations [1] to reduce overheating risk when retrofitting existing homes.

Experimental and numerical investigations of thermal performance of a Hemp Lime external building insulation

Hemp-concrete is a green material which has become nowadays highly recommended in the construction field. It finds applications as internal or external thermal insulator in wooden frame walls. At wall scale, studies proved that using Hemp-concrete in building envelope can improve indoor hygrothermal comfort. However, at building scale, hemp-concrete is scarcely studied. In that context, a French building in Grand-Est region, Champagne-Ardennes, employing hemp-concrete as external insulator is selected and studied. An apartment is monitored for several months. Indoor temperatures, relative humidities, thermal heat flux as well as external weather conditions are measured using sensors installed inside the apartment and a weather station at the building roof. Measurements underline the hemp-concrete ability to dampen external weather conditions by showing good results for both indoor temperature and relative humidity. Experimental approach is then coupled with a numerical validation at the wall and room scales using SPARK simulation tool. Investigations are conducted on thermal heat flux through the wall, indoor office air temperature, and relative humidity. Results show a good agreement between numerical values and experimental measurements.

Prediction Of Indoor Conditions And Thermal Comfort Using CFD Simulations: A Case Study Based On Experimental Data

In the present paper CFD tool was used for thermal comfort evaluation in natural convection and in transient conditions in a room by setting only the external weather conditions as input parameters. A survey in a classroom at the Department of Engineering, University of Perugia, was carried out and data required for the thermal comfort evaluation and CFD simulation model set up was acquired. The simulation model was validated with experimental data and it was used for the thermal and velocity profiles simulation and for the thermal comfort indexes calculation, according to UNI 7730.

Impact of weather conditions on the results of patch tests in the Tunisian central region

<p class="abstract"><strong>Background:</strong> Several factors can influence the results of patch-tests (PT) such as individual and external factors especially climate ones. The aim of the study was to<strong> </strong>study the impact of meteorological parameters on patch-tests results.</p><p><strong>Methods:</strong> This is a retrospective epidemiological study which concerned all patients of the Tunisian center, who consulted in the Dermato-Allergology Unit of Occupational Medicine Department of Farhat Hached University Hospital-Sousse (Tunisia) over a period of 5 years. All patients were tested by the European Standard Battery allergens (BSE). The eight allergens, most frequently encountered during the study period, were analyzed.</p><p class="abstract">Correlation and regression tests were used to calculate the relation of the patch-tests results with temperature and absolute humidity.<strong></strong></p><p class="abstract"><strong>Results:</strong> During the study period, 5560 patch-tests were analyzed. The results of these patch- tests for most allergens were not significantly influenced by external weather conditions. However, the irritant reactions for cobalt and colophony increased with the cold and dry climate. Some positive reactions to thiuram mix, cobalt and nickel were more frequent with humidity.</p><p class="abstract"><strong>Conclusions:</strong> The results of this current study support those of the literature. The majority of reactions to patch- tests didn’t seem to be influenced by weather conditions.</p>

A Smart Forecasting Approach to District Energy Management

This study presents a model for district-level electricity demand forecasting using a set of Artificial Neural Networks (ANNs) (parallel ANNs) based on current energy loads and social parameters such as occupancy. A comprehensive sensitivity analysis is conducted to select the inputs of the ANN by considering external weather conditions, occupancy type, main income providers’ employment status and related variables for the fuel poverty index. Moreover, a detailed parameter tuning is conducted using various configurations for each individual ANN. The study also demonstrates the strength of the parallel ANN models in different seasons of the years. In the proposed district level energy forecasting model, the training and testing stages of parallel ANNs utilise dataset of a group of six buildings. The aim of each individual ANN is to predict electricity consumption and the aggregated demand in sub-hourly time-steps. The inputs of each ANN are determined using Principal Component Analysis (PCA) and Multiple Regression Analysis (MRA) methods. The accuracy and consistency of ANN predictions are evaluated using Pearson coefficient and average percentage error, and against four seasons: winter, spring, summer, and autumn. The lowest prediction error for the aggregated demand is about 4.51% for winter season and the largest prediction error is found as 8.82% for spring season. The results demonstrate that peak demand can be predicted successfully, and utilised to forecast and provide demand-side flexibility to the aggregators for effective management of district energy systems.

Stochastic assessment of the energy performance of buildings

A building’s energy performance is a complex multi-dimensional metric consisting of a variety of parameters. Presented herein are the results of a stochastic analysis of the factors affecting a building’s energy performance. The analysis is based on the Dwelling Energy Assessment Procedure (DEAP) (amended for cooling loads) and the general guidelines prescribed by the European Energy Performance of Buildings (EPBD) Directive 2010/31/EU. Modifications to the DEAP model are made for investigating the effect of variable external weather conditions on a building’s energy performance, and to incorporate the additional energy requirement for cooling. Subsequently, a stochastic analysis for three dwelling types is performed to assess the impact of 68 factors on the energy performance of buildings, for 12 different regions in Europe. It is concluded that (1) the factors with the greatest impact on energy use are in descending order, the floor area, external weather conditions, dwelling’s envelope u value (roof, window, walls, and floors), the space heating system, ventilation, windows area and walls area; (2) the energy performance of a building follows a lognormal probability distribution function; (3) buildings in colder EU regions exhibit higher energy profiles and higher variability in their energy profiles than those in warmer regions.

Modeling warming predicts a physiological threshold for the extinction of the living fossil frog Calyptocephalella gayi

Global climate change will have a greater impact on ectotherms in tropical and subtropical communities than at higher latitudes, because ambient temperatures are closer to the upper thermal limits of species. Amphibian species are highly dependent on external weather conditions, and the effect of global warming on these has been evaluated recently. The Great Chilean frog (Calyptocephalella gayi) is an endemic, monotypic species and genus whose conservation status is considered Vulnerable because of high extraction pressure for human consumption, lack of regulatory measures and comprehension by its consumers. Their populations have also declined due to the loss and destruction of their habitats. C. gayi has not been considered as an object of physiological study, so this large species is not known as one that can adapt to current environmental changes. In this study we analyze the thermoregulatory capacity and thermal efficiency of C. gayi to determine its potential for climatic adaptation. The results indicate that this species is strictly a thermal-conformer; its thermal efficiency and its ability to withstand high temperatures allow it to sustain itself under a climate change scenario, however, it has thermal constraints that do not allow it to withstand temperatures greater than 30°C. By modeling its ontogenetic conditions mathematically, we project that the larvae are not in danger, although there is a group of around 4% which is very close to 30°C, which is the highest temperature recorded for the species. However, about 40% of subadults and approximately 47% of adult frogs will not survive the change of ~7°C projected for the following 85 years, which will affect future generations.

A11 Towards an integrated evaluation of the effects on health from smoke or toxic gas dispersion in the evacuation of subway tunnels

Background Understanding how subway tunnels perform during accidents or malicious attacks resulting in the release of smoke or hazardous toxins is key in establishing evacuation strategies that reduce the loss of life or effects on public health. During such emergency situation, the natural background air current caused by the air exchange between the station and outside, has an important influence on the dispersion of smoke and/or toxic agents. Over 60% of deaths in fires are caused either wholly or partially by inhalation of smoke or toxic gases. Thus evacuation strategies that provide routes which reduce the exposure time of individuals to a toxic environment could potentially reduce the loss of life or effects on an evacuee's health. The strategy go up and take the nearest exit to the surface might not be the best response. To support this assessment an understanding of; the air flow driving the motion of smoke, its links with internal climatology and external weather conditions and the evacuation capabilities of subway tunnels, is needed. Methods To support this exploration, 3D Computational Fluid Dynamic models have been developed, to validate field measurements and to gain an understanding of the internal airflow momentum and energy transfer capacity of subway stations in relation to external climatic factors and its effect on the dispersion of smoke and/or toxic agents. By integrating results with evacuation simulations, visual diagnostic and predictive tools which display; the background air flow within the subway, the dispersion of smoke and/or toxic substances, the resulting reduction of visibility and the evacuation of pedestrians, are in development to further our understanding in both subway climatology and integrated evacuation strategies. Results Initial results show promising links between external climatic factors, the subway climatology and the ability to predict the dispersal of smoke/toxins. It has also been established that by navigating pedestrians on routes away from smoke and/or toxic dispersion can significantly reduce the number of fatalities and effect on evacuee's health. The possibilities of integrating these findings is allowing for a more integrated assessment to be carried out. Conclusions The study discussed demonstrates that by integrating the datasets mentioned, a greater understanding of the effect subway climatology has on evacuations strategies of subway stations can be understood. It is shown that accessible technology and software, along with methodologies developed, supports the assessment and development of integrated evacuation strategies that reduce the loss of life or effects on public health. Language: en

First Steps to Develop Biomimicry Ideas

Abstract There is urgent need for new building insulation materials or building thermal envelope concepts while it is often economically not feasible to achieve nearly zero energy level for buildings in northern climate. The purpose of this study is to research and create solution for applicable facade system or wall construction itself that has dynamic optical and dynamic properties that will adapt to external weather conditions and will be able to react to different outdoor and indoor temperature and lighting conditions using biomimetic principles avoiding the necessity for additional energy input. The goal of such solution is to gather the energy of Sun in summer for heating in winter.

Climate threats to the earth-built heritage of Scotland

The most significant concentration of surviving vernacular mudwall structures in Scotland is found in and around the town of Errol in the Carse of Gowrie. Mudwall, or cob, is particularly susceptible to climate-related impacts such as water ingress and freeze–thaw cycles. A lack of recognition can exacerbate the effects of these factors significantly. Using two sites as representative case studies, this paper considers the issues typically encountered. The procedures used in monitoring the performance of each building within a regional climate context are outlined. Using climate models and current weather data, the local climatic context within which these structures exist is considered. Climate-related impacts can then be considered for future scenarios. Temperature and humidity data were collected concurrently from targeted areas within the walls of both structures for over a year from April 2012, a period that exhibited a range of extreme weather events in the Carse of Gowrie. The system of datalogging at each structure is discussed and results considered against external weather conditions using decomposed time series statistical analysis. Recommendations are offered considering how an integrated approach to the analysis of historic mudwall structures can be achieved.

Interactions between spray drift and sprayer travel speed in two different apple orchard training systems

Trials were carried out in apple orchards of two different training systems to assess the relationship between spray drift and parameters of spraying with an emphasis on the sprayer’s travel speed when applying different solutions, such as pesticides or fertilizers, onto the apple trees. The assessments were based on the following factors: per cent of spay drift, two sprayers (axial- and radial-fan sprayer), two training systems (super spindle and modified slender spindle), spray droplet size (fine or coarse droplets) and the sprayer’s travel speed (5 vs. 10 km h−1). The studies were conducted in the spring and summer seasons under similar external weather conditions to test any seasonal effects that might occur. In this paper, all tested factors and interactions were found to have a significant effect on the spray drift during spray application. For instance, the increase in sprayer speed reduced the spray drift percentage. Other factors, such as sprayer type (axial fan and radial fan) and tree training system, had an impact on spray drift as well.

Performance evaluation of two solar photovoltaic technologies under atmospheric exposure using artificial neural network models

Experimental results are presented from monitoring the electrical power after exposure to external weather conditions of two different solar modules technologies, one of them a mono-crystalline 55W silicon and the other a flexible organic solar module of 12.4W. During the observation period the temperature, relative humidity, and irradiance were monitored. With these records an artificial neural network model was trained, validated and tested, delivering the electric power based on the three monitored parameters. These models were subjected to a sensitivity analysis with respect to the input variables and from the electrical point of view, a better performance for the organic flexible module was achieved specially under conditions of higher relative humidity, higher temperatures and lower irradiances. Finally this tool helps for prediction of the performance of these photovoltaic technologies at broad different environmental conditions.

Condition Monitoring of Wind Power System With Nonparametric Regression Analysis

Condition monitoring helps reduce the operations and maintenance costs by providing information about the physical condition of wind power systems. This study proposes to use a statistical method for effective condition monitoring. The turbine operation is significantly affected by external weather conditions. We model the wind turbine response as a function of weather variables, using a nonparametric regression method named least squares support vector regression. In practice, online condition monitoring of wind power systems often relies on datasets contaminated with outliers. This study proposes to use a weighted version of least squares support vector regression that provides a formal procedure for removing the outlier effects. We determine the decision boundaries to distinguish faulty conditions from normal conditions by examining the variations in the operational responses that are significantly affected by external weather. The results show that the proposed method effectively detects anomalies.

Training for Environmental Risks in the Black Sea Basin

The Potential Emergency Situations Simulator (PESS) for Constantza Maritime University (CMU) should provide training and practicing of the students or course attendants in choosing the best strategies in a given emergency situation, which is an informational high entropy, multi‐tasking, fast changing environment. The simulator is used for the realistic modeling of a crisis situation and it is useful for both marine officers and emergency situation officials. The simulator will be used as an educational instrument enabling the interactive study of the different emergency situations. It has the aim of training students to efficiently react to emergency situations such as a leak from a ship/chemical plant, fire, poisonous gas emissions, or any other situations that could show a potential danger. The trainee must be provided with realistic information and the response of the model on the actions of the trainee must be in accordance with the real conditions and scientific based. It must be possible to accelerate the simulation speed without loss of information or functionalities. The input of the external weather conditions is a must, as well as the trainee‐oriented graphic interface. It must be possible to change the chemical and physical properties and characteristics of the different polluting agents. The simulator is also used to evaluate the best strategies to be followed in an ongoing crisis. In order to fulfill this aim, the simulation must have the capability to receive data from various sensors, transducers and servers. The courses are designed to accommodate up to six course participants. Each course includes course material such as course manuals and other documents. The courses include hands‐on experience with simulator operations and maintenance. To help the start up of the simulated emergency situations training at Constantza Maritime University, the authors have made a manual which includes some well‐designed exercises with scenarios, initial conditions and relevant documentation. The exercise documentation includes the exercise objectives, exercise guidance, instructor guidance, expected results and all other information to make the exercise successful for an inexperienced instructor.

Effects of different collector’s area on the coupling of a thermosiphon collector and a single zone

The novelty of this paper is the coupling between a thermosiphon collector and a single zone with the following details; a thermosiphon system (TYPE 45) which uses the solar energy as an unlimited renewable energy to produce the heat by using an internal coupling of a flat plate collector and a storage tank in a closed loop realized in TRNSYS. Consequently, the user simply utilizes TYPE 45 as thermosiphon ready to be run, and a single zone (TYPE 19) is a complex type which is designed for residential buildings that can be specified by the user in order to obtain an acceptable heating within a house. The user specified the characteristics of the internal space, external weather conditions, walls, windows, and doors. To facilitate this description, the parameters and inputs for this component are organized in separate table according to a logical structure. According to us, the choice of this model of thermosiphon coupled with a single zone can have multiple interesting engineering applications, in particular ameliorating the mode of the heating in residential buildings. Two flat plate collectors of aperture area of 6 and 8m2 are modeled. The solar fraction of the entire system is used as the optimization parameter. The temperature of the water in the storage tank, the collector’s temperature, the temperature inside and outside the house, the solar fraction for different collector areas and the total energy were also measured in 11h operation in January and 2880h operation in winter. The average solar fraction obtained was 85% and the system could cover all the hot water needs of a house of six people. The maximum auxiliary energy was needed during 11h operation in January and 4months in winter. The results show that by utilizing solar energy, the designed system could provide 40–70% of the hot water demands in winter.

Experimental thermal characterization of a Mediterranean residential building with PCM gypsum board walls

A two-storey typical family house was built in the mid-western part of Greece, comprising a load bearing steel skeleton and dry wall systems. Its walls consist of multiple layers of insulation materials and gypsum plasterboard panels containing Phase Change Materials (PCMs) for thermal energy storage purposes. A detailed matrix of sensors was installed in different locations of all external walls of the house, as well as indoors, in order to provide detailed temperature measurements and thus lead to a thorough depiction of the house's thermal behaviour. In this work, experimental data obtained during the first year of monitoring (2011) are presented. Throughout this particular monitoring period the house purposely remained closed, unoccupied and no energy systems were installed. Hence the presented analysis focuses on the thermal characterization of the house's walling system. Average monthly temperature, decrement factor and time lag values are presented for each room–wall and are discussed with respect to their orientation and exposure to the external weather conditions. Furthermore, measurements conducted on different layers of the living room's east wall aim to examine the influence of PCMs in the wall's thermal response. It is shown that within the adopted conditions (unoccupied house/no energy systems), the thermal mass of the walling system is enhanced during late spring, early summer and autumn, due to the PCM implementation, resulting also in a decrease of the decrement factor by a further 30–40% and an increase on the time lag of approximately 100 min.

Moisture Migration Mechanism in Granite Residual Soil Embankment under the Combined Action of Rainfall and Capillary

Taking the granite residual soil embankment of Fujian Province as an example, this paper investigated the moisture migration mechanism in granite residual soil embankment based on the finite difference technology. The results show that the moisture migration of the shallow layer of the embankment displays up first and down later in dry seasons. In rainy seasons, the negative pressure head of the embankment’s upper soil increases, and range of rainfall variation of the initial period is much sharper than the later period. Meanwhile, at the toe of slope, the rain firstly supplies the groundwater, making it a weak location. After the rain, the contour line of negative pressure head in the upper embankment gradually becomes sparse, and the gradient gradually decreases in the embankment. The fluctuation of negative pressure head on foundation surface decreases with the depth of groundwater. As to the low embankment, the change of the embankment moisture mainly depends on the external weather conditions when the groundwater level is deep and the moisture is mainly affected by groundwater when the groundwater level is shallow.

Numerical Simulation Results and Laws of Transmission Lines Ice-melting

Based on the numerical simulation model of icing, the impact on icing of the current was further investigated. The critical current value with the meteorological conditions of foreign objects, as well as the physical parameters of the aerial cable itself change the law. The calculation results showed that the critical current value depends on the external weather conditions and the aerial cable itself, the physical parameters, and the critical current and the ambient temperature, wind speed, relatively good linear relationship.