↓ Direkt till sidans innehåll
↓ Direkt till sidans sekundära innehåll (sidomenyn)

Träfflista för sökning "WFRF:(Gál Csilla V) "

Sökning: WFRF:(Gál Csilla V)

Resultat 1-31 av 31

Sortera/gruppera träfflistan

Sortering: Träffar per sida:

Numrering	Referens	Omslagsbild	Hitta
1.	Lelovics, Enikő, et al. (författare) Design of an urban monitoring network based on local climate zone mapping and temperature pattern modelling 2014 Ingår i: Climate Research (CR). - : Inter Research. - 0936-577X .- 1616-1572. ; 60:1, s. 51-62 Tidskriftsartikel (refereegranskat)abstract The recently developed Local Climate Zones (LCZ) classification system was initially not designed for mapping, but to classify temperature observation sites. Nevertheless, as a need arose to characterize areas based on their distinct thermal climate, utilizing LCZ classes for mapping was a logical step. The objectives of this study were (1) to develop GIS methods for the calculation of different surface parameters required for LCZ classification; (2) to identify and delineate the LCZ types within the study area using the calculated parameters; and (3) to select representative station sites for an urban monitoring network utilizing both the mapped LCZs and the modelled mean annual temperature surplus pattern in Szeged, Hungary. The study used remotely sensed data, maps and GIS databases of the city and its surroundings. The basic area of calculation was the lot area polygon, consisting of a building and its close vicinity. Adjoining polygons classified with identical or similar parameters were merged to obtain LCZs of appropriate size. As a result, 6 built LCZ types were distinguished in the studied urban area. The temperature pattern in the city was provided by an empirical model. The siting of stations took both the LCZ map and the modelled temperature pattern into account. The lampposts onto which the stations were to be mounted were determined by field surveys. The bias between the temperature pattern interpolated from the 24 stations and the initially estimated distribution by the model was found to be small. LCZ mapping is the first step in the development of urban climate maps (UCMs) that carry information on the spatial distribution and magnitude of the heat stress (thermal loads) and on the ventilation ability (dynamical potential) of different urban areas.
2.	Lelovics, Enikő, et al. (författare) Intra-urban temperature observations in two Central European cities, a summer study 2016 Ingår i: Időjárás. - Budapest, Hungary : Országos Meteorológiai Szolgálat. - 0324-6329. ; 120:3, s. 283-300 Tidskriftsartikel (refereegranskat)abstract This paper presents an urban climatological application of the urban monitoring systems – recently implemented in Szeged, Hungary and Novi Sad, Serbia – using the first set of data collected during the summer of 2014. In order to ensure a representative number and placement of stations, the selection of measurement sites was based on Local Climate Zone (LCZ) maps developed for both cities. Present paper concentrates only on the intra-urban temperature pattern characteristics expressed by the thermal reactions of the different LCZ classes in both cities. The daily temperature indices (e.g., summer days) have the highest values in the densely built up LCZs. The diurnal cycle of surplus temperatures by LCZ classes under anticyclonic weather conditions were found to be similar in the two cities with higher absolute values in the case of Novi Sad. During summer, the diurnal variation of conventional heat island intensity confirms the general knowledge that it remains positive with highest values at night, while negative values occur predominantly during the day.
3.	Gál, Csilla V (författare) A városi tér szerkezete és hatása a mikroklímára [Urban space and structure and its effect on the urban microclimate] 2017 Ingår i: 43. Meteorológiai Tudományos Napok. 2017. November 23-24. Mikro- és mezoskálájú légköri folyamatok modellezése. Az előadások összefoglalói.. - Budapest, Hungary. - 9789639931145 Konferensbidrag (refereegranskat)abstract A városok sajátos éghajlata, a városklíma, a természetes környezethez képest módosult éghajlattal jellemezhető. A klímaparaméterek városi módosulásának hátterében a beépített felszínek megváltozott energiaháztartása áll. Míg a városok éghajlata markánsan elkülönül a környező természetes területek éghajlatától, a városokon belül is jelentős klimatikus különbségek alakulnak ki. Ezen különbségek kialakulására alapvető hatással van a beépítettség foka, valamint a zöld területek részaránya. A városokon belüli éghajlati különbségek tanulmányozása mérések és numerikus szimulációk révén lehetséges. Utóbbiak segítségével széleskörűen tanulmányozható a beépítettség, a városokra jellemző mesterséges anyagok, valamint a városon belül alkalmazott zöld- és kék infrastruktúra elemeinek hatása a kialakuló mikro- és lokális éghajlatra, illetve mindezek hatása a lakosok komfortérzetére. Eme ismeretanyagra alapozva megfogalmazhatók olyan várostervezési irányelvek, melyekkel az éghajlatváltozással kombinálódó városklíma negatív hatásai mérsékelhetőek, s a városlakók számára klimatikus szempontból élhetőbb környezet teremthető.Tanulmányomban Budapest jellemző városi beépítési formáit, s a köztük lévő mikroklimatikus különbségeket vizsgálom numerikus szimulációk útján, különös tekintettel a nyári hőterhelés mérséklésére irányuló várostervezési beavatkozások eredményességére az egyes beépítési formák esetén. Az egyik ilyen beavatkozás az épülethomlokzatok albedójának növelése nagyobb sugárzás-visszaverő képességű anyagok, illetve festékek alkalmazása révén. Egy másik jellemző beavatkozás a zöldterületek részarányának növelése, melyet tanulmányomban a lombkorona borítás értékének változtatásával vizsgálok. A különféle beépítési formák, homlokzat albedók és korona borítottság értékek komplex hatásának feltárására az ENVI-met szimulációs software-t alkalmaztam. Az eredmények alapján elmondható, hogy a megnövekedett albedó következtében a napsugárzásnak kitett homlokzatok hőmérséklete – s ez által az épületek hőterhelése is – csökken. A visszavert sugárzási hányad megnövekedése azonban az épületek között sugárzás többletként jelenik meg, mely többlet a nem módosított albedójú felületek (utak, terek) nagyobb sugárzási terheléséhez és ezáltal a városi határréteg felmelegedéséhez vezet. Ezzel ellentétben, a korona borítottság növelése a városi határrétegben a rövidhullámú sugárzás és a léghőmérséklet csökkenését eredményezi. Mivel ezen tényezők hatása a lakosok komfortérzetét és az épületeket érő hőterhelést is előnyösen befolyásolja, a közterületek fásítása a nyári hőterhelés mérséklésére irányuló várostervezési beavatkozás egyik hatásos eszköze lehet.
4.	Gál, Csilla V (författare) Borrowing ideas : The changing form of metropolitan housing in Budapest 2012 Konferensbidrag (refereegranskat)abstract Capitals often serve as national testing grounds for urban planning, policy and design because of their role representing the state. As such, they not only accommodate local reforms and initiatives, but international concepts and practices as well. A strong reliance on imported ideas characterizes small or late-urbanizing nations, as their limited resources necessitate the adoption of tested examples over uncertain experimentation. In planning history, one can trace the adjustment of existing practices in the accommodation of novel ideas in the development of housing. Located at the crossroads of culture, technology, economy and policy, the design and construction of urban housing reflects the complex interplay of these competing forces.This paper focuses on the history of Budapest's metropolitan housing over the past two centuries. Through a close examination of the development of four characteristic housing types, the article sheds light on the local treatment of these foreign concepts by examining the social, cultural and political challenges that accompanied their introduction.The peculiar courtyard tenement of Budapest became the dominant model of urban housing over the course of the nineteenth century. Although its origin was never discerned, this form was both linked to the Viennese Hof and to the local building tradition. Across Europe, the reformed urban block emerged as an appropriate configuration for metropolitan dwelling at the beginning of the twentieth century. Despite their perceived superiority, only a handful of such residences were built prior to the 1930s due to legal, political and financial challenges. The third form of housing, the Zeilenbau, developed out of the German Siedlungen tradition during the interwar period. Even though the returning Bauhaus students promulgated this concept rather early, it did not gain acceptance until after the Second World War. Then, following the brief Social Realist intermezzo, the model was adjusted to meet the narrowly defined goals of the State. The fourth configuration emerged over the past few decades. Influenced by international trends emphasizing tower-living, this type of housing gained a distinctly local character resulting from height restrictions enforced by the city.The examined cases reveal that the metropolitan housing forms of Budapest are based on imported concepts. Furthermore, the paper demonstrates that the driving force behind the local adjustment of these ideas was not the often romanticized local tradition, but the municipal building code and the economic-political elite.
5.	Gál, Csilla V (författare) Experiencing Urban Climate in the Nation's Capital 2015 Konferensbidrag (populärvet., debatt m.m.)
6.	Gál, Csilla V, et al. (författare) Heat mitigation with shade trees : the role of landscape design and tree parameters in ameliorating summertime heat stress in a Central-European square 2017 Konferensbidrag (refereegranskat)abstract Climate change projections for Central Europe indicate a significant rise in summertime temperatures and an increase in the frequency and severity of extreme heat events. Combined with the peculiar climate of cities—characterized by the Urban Heat Island effect and reduced ventilation due to high building density—climate change is expected to have more pronounced effects in urban environments. Shade trees are demonstrated to be one of the most effective means to mitigate heat stress in cities. However, very few studies have evaluated systematically the impact of different landscape design and tree parameters (e.g. the species selection or the spatial distribution) on the heat mitigation effectiveness of shade trees. This study aims to assess the role of vegetation transmissivity, canopy size and tree distribution in a medium-sized Central-European square. The rectangular Bartók Square, located in the inner city of Szeged (Hungary), was selected as a study area. The numerical simulations were carried out with the radiation model SOLWEIG (v.2015a). The necessary meteorological data, collected on clear and warm summer day, was obtained from a nearby weather station run by the Hungarian Weather Service. The default model was built on the basis of available GIS data and utilized tree related parameters from detailed field measurements (tree location, canopy size and shape, etc.). Crown transmissivity data originated from a preliminary, long-term radiation measurement survey covering the vegetation period. Alternative scenarios were constructed with the following characteristics:1) keeping the original tree layout of the square, the initial tree crown transmissivity of 0.0678 was changed to small (0.0243) and high (0.1328) values;2) keeping the original canopy volume, two additional scenarios were introduced with evenly distributed trees of different crown sizes: that of several small trees and of fewer large ones;3) keeping the original canopy volume and using the same number and size of trees, we assessed the role of tree distribution by introducing a scenario were the trees were arranged along the bounding facades of the square—this scenario was compared to the evenly distributed configuration. In order to evaluate the impact of vegetation, all scenarios are reported in reference to a theoretical, nonvegetated square. Since several studies revealed that mean radiant temperature (Tmrt) plays a key role in summertime heat stress in the European context, this parameter was selected as performance indicator. Tmrt combines the heat effect of all short-and long-wave radiation fluxes reaching the human body. Our results indicate that when shade is provided for the facades only, the nighttime Tmrt surplus nearly disappears. However, while horizontal long-wave radiation fluxes have a greater impact on human thermal comfort due to the different absorption coefficients of the human body (0.7 vs. 0.95 for short and long-wave radiation, respectively), providing shade for the facades only is not a successful daytime heat mitigation strategy in open urban places. Comparing the influence of vegetation transmissivity revealed that low transmissivity species were able to reduce Tmrt by only 2C on average during the day. According to our case study, when transmissivity and canopy volume is kept constant, considerable mean radiant temperature reduction can be achieved by evenly distributed mature trees.
7.	Gál, Csilla V (författare) Mean radiant temperature modeling, A comparative model evaluation 2018 Konferensbidrag (refereegranskat)abstract As a result of the changing climate with trends of rising temperatures and increasing extreme heat events, urban planners and city officials have recently taken a great interest in improving the climate of cities and maintaining comfortable outdoor conditions in spite of these trends.In order to meet the demand for this special knowledge and to deliver scientific assistance, several numerical models have emerged with an aim to assess the microclimate of cities and their influence on human thermal comfort over the course of the past decade. While these tools differ both in the human thermal comfort indices they deliver and in their numerical modeling approach, they all rely on the calculation of mean radiant temperature—the driving parameter of outdoor human thermal comfort. While the assessment of models lags behind the perpetual software updates and releases, the documentation of many such models is also lacking or insufficient. In addition, a great deal of existing validation studies assess clear cut situations where the site is either sunlit or in shade, whereas conditions in the urban environment are generally more complex. Given both the growing importance the outdoor thermal environment of cities and the role played by these tools, reporting on their performance is of high importance.The aim of this study is to assess the ability of several recently emerged or updated microclimate models to reproduce mean radiant temperature (Tmrt) in a complex urban setting. The evaluation is made against field data obtained by integral radiation measurements. Results indicate that most microclimate models underestimate Tmrt both at sunlit locations and at night, whereas in shade Tmrt is generally overestimated. These errors are related to the surface temperature parametrization, the isotropic sky assumption, simplifications in the reflected shortwave radiation calculation and the incorrect representation of a standing person.
8.	Gál, Csilla V, et al. (författare) Mean radiant temperature modeling outdoors : A comparison of three approaches 2020 Konferensbidrag (refereegranskat)abstract As a result of both urbanization and climate change, the thermal environment of cities is deteriorating steadily. Thus, urban planner and city officials are increasingly under the pressure maintain livable environments in cities. The quickest and most economic means to assessing the performance of various urban heat mitigation strategies is via numerical modeling. Owing to these advantages, the approach gained popularity over the past decade, as well as resulted in the proliferation of microclimate models. The driving parameter of outdoor human thermal comfort is radiation, which is accounted for via mean radiant temperature (Tmrt). While this parameter is at the center of most outdoor thermal comfort indices, it is also rather challenging to measure and calculate. Along with the recent emergence of microclimate models, the ways of calculating outdoor Tmrt also multiplied. However, beyond individual model validations, very few studies have attempted to compare the performance of different models. Thus, the aim of this paper is to assess the performance of three microclimate models in estimating Tmrt in the urban environment. The reviewed models are VTUF-3D, the Grasshopper add-ons of Rhinoceros 3D and the latest ENVI-met version utilizing the Indexed View Sphere (IVS) algorithm. The adopted spatial resolution in each model were not identical. In the case of ENVI-met and VTUF-3D, 3 and 5 meter resolutions were used, respectively. The Grasshopper add-on was set to calculate surface temperatures at 6 m resolution and view factors (along with Tmrt) for a denser, 3-meter spatial grid. The model assessment utilized data from a 26-hours-long integral radiation measurement, conducted in Szeged (Hungary). The observations were undertaken along the four bounding facades of Bartók Square during a clear summer day in 2016. According to the preliminary results, ENVI-met performs the best when the observation sites are exposed to direct solar radiation. However, it underestimates Tmrt values by up to 10 ºC when the sites are in shade and during night. In general, both VTUF-3D and the Grasshopper add-on underestimate Tmrt values considerably during sunlit conditions (exceeding 20 ºC at times), but reproduce radiative conditions well at night (with errors remaining below 4 ºC). One reason for the above errors is the way Tmrt is calculate by these models. While Tmrt calculations differ in each model, at the core of their adopted approaches is a Tmrt estimation developed for indoor environments---which was later adopted to outdoors. One of the lingering simplification is the assumption of a seated posture and/or the conceptualization of the human body as a sphere. The other transferred simplification is the assumption of small temperature differences between the surrounding surfaces. These assumptions not only diminish the impact of horizontal fluxes, but also depict a less diverse radiative environment.
9.	Gál, Csilla V (författare) Microclimate assessment of urban block typologies, a simulation approach 2012 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Urban environments are characterized by a diversity of microclimates. To manage this complexity, assessments generally involve a certain kind of simplification: either an areal constriction (e.g. the analysis of distinct urban squares), or a spatial reduction (e.g. the reliance on the urban canyon model). This paper approaches the task at the scale of the urban block. In the analysis of metropolitan urban block typologies, the study adopts Probáld's concept of microclimate assemblages. With the presented approach, the research aims to compliment existing urban microclimate assessments. Utilizing the numerical modelENVI‐met, this paper focuses on the effect of building configurations.
10.	Gál, Csilla V (författare) Modeling mean radiant temperature in outdoor spaces : A comparative numerical simulation and validation study 2018 Konferensbidrag (refereegranskat)abstract Cities are increasingly under pressure to address the challenges of climate change. One of the most pressing and unifying issue in this respect is the maintenance of comfortable outdoor conditions despite rising air temperatures and increasing extreme heat events. As a means to inform urban planner and city officials, the assessment of outdoor thermal comfort conditions—either via numerical modeling or field measurements—have gained popularity over the past decade. While measurements can deliver highly accurate data, they are expensive and time-consuming endeavors that can only inform us about the conditions in an existing environment on a specific day and time of the year. In contrast, numerical modeling allows us to evaluate alternative urban design scenarios as well as to grasp the spatial and temporal variability of outdoor human thermal comfort conditions.Given the advantages of numerical modeling and the increasing computational power of personal computers, several tools have emerged with an aim to assess the microclimate and human thermal comfort impacts of urban planning and design decisions. While these tools differ both in the human thermal comfort indices they deliver and in their numerical modeling approach, they all rely on the calculation of mean radiant temperature, in one way or another. Mean radiant temperature (Tmrt), the driving parameter of human thermal comfort in outdoor spaces, requires the modeling of both short- and long waver radiation fluxes. While different calculation methods exist to deriving this parameter, most models also introduce some kind of numerical simplification to increase computational speed. The multitude of numerical approaches in deriving Tmrt, coupled with the high spatial and temporal variability of this parameter, can result in a range of values delivered by these tools. Given both the growing importance of improving the outdoor thermal environment of cities and the role these tools play in it, reporting on their performance is of high importance.The aim of this study is to assess popular microclimate models in their ability to reproduce the complex radiative environment of cities, as indicated by Tmrt, and to inform to the research and design community about their performance, compared to integral radiation measurement derived filed data. While the documentation of some numerical simulation tools is lacking or incomplete, this paper will nevertheless attempt to shed lights on the reasons behind the disparities in the derived Tmrt values. Initial results indicate that most microclimate models have a tendency to underestimate nighttime Tmrt together with daytime values when the location is exposed to the sun. In contrast, when the locations become shaded, Tmrt values are generally overestimated. In general, these errors indicate issues with surface temperature parametrization and point to the greatest challenge of the numerical simulation community.
11.	Gál, Csilla V, et al. (författare) Modeling mean radiant temperature in outdoor spaces : A comparative numerical simulation and validation study 2020 Ingår i: Urban Climate. - : Elsevier BV. - 2212-0955. ; 32 Tidskriftsartikel (refereegranskat)abstract The parameter governing outdoor human thermal comfort (HTC) on warm, clear-sky days is radiation. Its effect on HTC is accounted for by mean radiant temperature (Tmrt). While Tmrt differences owing to different measurement methods are well established, the impact of different computational approaches have not been systematically evaluated. This study assesses the performance of three microclimate models in their ability to estimate Tmrt values in complex urban environments. The evaluated models are RayMan Pro, SOLWEIG and ENVI-met. The model evaluation encompasses both the comparison of modeled Tmrt values with those derived from observations and model intercomparisons with analyses extending to several radiation terms and parameters that comprise or explain the resultant Tmrt. Results indicate that the models systematically underestimate nighttime Tmrt. SOLWEIG and ENVI-met tend to overestimate Tmrt during prolonged periods of shade and underestimate when the sites are sunlit. RayMan underestimates Tmrt values during most part of the day. The largest Tmrt errors occur at low sun elevations in all three models, mainly as a result of underestimated longwave emitted and shortwave reflected radiation fluxes by the adjacent facades. These errors indicate room for improvement with regards to surface temperature estimation and shortwave reflected radiation calculations in the models.
12.	Gál, Csilla V (författare) Revisiting the urban block in the light of climate change : A case study of Budapest 2014 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Since the beginning of the twentieth century, the urban block configuration of free-standing buildings has been deemed superior to other built forms, as it provided the necessities of modern healthy living: sunlight and fresh air. In light of climate change, the dissertation aims to reevaluate these long held beliefs and to reintroduce microclimate as an urban design consideration. The study takes four metropolitan block typologies of Budapest as cases to clarify the microclimate influence of key urban design parameters by means of a numerical simulation study. The effects of built form, orientation, vegetation and facade properties are evaluated for a typical summer day. The cases are assessed on the basis of diurnal potential air and mean radiant temperatures within the urban canopy layer. Numerical modeling is performed by ENVI-met and analysis is conducted with MATLAB. The findings indicate that built form and vegetation are key factors governing the microclimate. During the day, intraurban cool island develops between dense configurations and in tree-shaded urban canopies. Orientation is decisive in configurations with large open spaces, where east-west alignment corresponds with peak radiant and air temperatures. Apart from albedo, facade properties have little effect on the microclimate. The rise of air temperature with facade albedo is the outcome of canopy floor heating, resulting from the increased ratio of reflected shortwave radiation. A short-term field experiment was conducted in Budapest to complement the numerical simulation study and to evaluate ENVI-met. The measurement campaign utilized six air temperature and humidity loggers. Additionally, wind speed, air temperature and humidity were recorded at the pedestrian level during an anticyclonic period. In courtyards, thermal stratification developed by day with cool island intensities up to 7 C. In the case of open configurations, neither cool island, nor stratification was observed. The comparison of measured and predicted air temperatures revealed the strengths and weaknesses of the numerical model. In general, predicted temperatures had a decreased diurnal range with maximum values systematically underestimated. ENVI-met also failed to reproduce the thermal stratification in courtyards. Despite these shortcomings, the predicted trends and the relative microclimate differences between the configurations agreed with observations reasonably well.
13.	Gál, Csilla V (författare) The effectiveness of shade trees for urban heat mitigation, a comparative numerical simulation study 2016 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract As a result of climate change, many regions are projected to see increases in air temperatures and extreme heat events over the coming decades. Since these trends are expected to exacerbate existing conditions in cites, urban heat mitigation will be one of the key challenges of the twenty-first century. A frequently advocated means of mitigating urban heat is through shade trees. Through the reduction of air and radiative temperatures trees not only improve outdoor human thermal comfort, but also reduce the cooling loads of buildings. This paper investigates the impact of different canopy cover ratios and tree layouts on the urban microclimate. The numerical simulation study utilizes four characteristic dense urban configurations from Budapest (Hungary) to assess the influences of these factors on the effectiveness of shade trees in mitigating urban heat. The study applies ENVI-met for microclimate simulation and MATLAB for the analysis and visualization of the results. Microclimate conditions within the urban canopy layer are examined on the basis of diurnal air and mean radiant temperatures. Preliminary results indicate that the effectiveness of shade trees is the function of the urban configurations' initial thermal performance. Since microclimate improvements by way of trees are primarily achieved through shading, greatest reduction in radiative temperatures is achieved in configurations with large open spaces. In the case of air temperature, increasing the canopy cover increases the added benefit of temperature reduction—indicating that reduced turbulence can in certain cases be beneficial.
14.	Gál, Csilla V (författare) The impact of built form on the urban microclimate at the scale of city blocks 2014 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Following the first oil crisis, Philip Steadman concluded that as a result of the twentieth-century developments in architecture "the means for environmental control within and around buildings, which was formerly achieved through effects of mutual shading, enclosure and wind protection, [were] lost" (Steadman 1975). Nevertheless, subsequent building regulations further strengthened the already prevailing design emphasis on single buildings by introducing energy measures that largely disregarded the effects of the surrounding environment [of the local climate]. While in countries with mild to moderate climates wintertime energy conservation became the primary preoccupation, climate model projections indicate rising temperatures and prolonged heat waves in these parts of the world. As a consequence, architects and planners increasingly find themselves ill equipped to address the challenges of climate change.The aim of this paper is to assess the microclimate performance of built form at the scale of city blocks. The study takes four metropolitan urban block typologies from Budapest as models. The purpose of this analysis is to obtain basic understanding regarding the interaction between built forms and microclimates in general, and to gain knowledge regarding the microclimatic behavior of these existing typologies in particular. The understanding of the performance of these forms is necessary both for developing climate- sensitive design principles and for proposing effective climate mitigation strategies.The comparative numerical simulation study utilizes ENVI-met and MATLAB. The models are compared on the basis of diurnal air temperature, mean radiant temperature and Predicted Mean Vote cycles. The analysis found mean radiant temperature a good indicator of the built form's influence on the canopy layer thermal environment. It is sensitive to directionalities in the model and signals problematic periods and places with high surface and air temperatures. Consequently, mean radian temperature that governs outdoor thermal comfort on warm and hot days is also useful to analyzing and understanding the effects of mutual shading.
15.	Gál, Csilla V (författare) The influence of built form and vegetation on the canopy layer microclimate within urban blocks 2014 Ingår i: Acta Climatologica et Chorologica. - : University of Szeged, Faculty of Sciences. - 1587-5903. ; 47-48, s. 43-52 Tidskriftsartikel (refereegranskat)abstract A numerical simulation study was conducted to reveal the effects of built form on the canopy layer microclimate at the scale of city blocks and to evaluate the role of vegetation in modifying these environments. The study took four metropolitan urban block typologies from Budapest as models and compared their microclimate dynamics with and without vegetation. Microclimate modeling was performed by ENVI-met (Bruse 2011), while MATLAB was utilized for the data analysis. The findings indicate that built form and vegetation are key factors governing the canopy layer microclimate. Their influence is primarily exerted through shading and enclosure.
16.	Gál, Csilla V (författare) The influence of built form on the microclimate within urban blocks 2014 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Urban morphology, that is the characteristic size, shape, orientation and distribution of buildings, plays a significant role in affecting the climate within cities. However, despite computational advances over the past decades, simulation studies investigating the effect of built form on the microclimate generally adopt either the array of cubes or the urban canyon model. What these models leave out are the microclimatic conditions within urban blocks and other complex environments that also constitute spaces of human activity. While the recently developed local climate zone (LCZ) classification system also took urban morphology to delineate ten urban categories, it also conceptualized built form as a cluster of free-standing buildings and therefore failed to account for semi-enclosed spaces. The aim of this study is to assess the effect of built form on the microclimate at the scale of the urban block. Taking the built environment of Budapest as a starting point, the study compares the microclimatic performance of four historic metropolitan urban block typologies. The comparative numerical study focuses on the influence of built form and orientation, and employes both a three- dimensional microclimate model (ENVI-met) and a high-level language for numerical computation and visualization (MATLAB). The presentation will compare the diurnal-cycles of air temperature, mean radiant temperature and Predicted Mean Vote of the four urban block configurations. The insights of this study could facilitate the development of targeted climate change adaptation strategies.
17.	Gál, Csilla V (författare) The influence of facade properties on the canopy layer microclimate within city blocks 2014 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The application of high albedo surfaces and 'cool' materials — characterized by high solar reflectance and emissivity — are often advocated as a means to mitigate the urban heat island (UHI), to decrease indoor temperatures and consequently to reduce cooling loads in warm weather. The frequently described mechanism that links higher surface albedos with lower outdoor temperatures emphasizes the role of decreased surface temperatures in the process. Admittedly, the high albedo approach to UHI mitigation is primarily recommended for roofs, which, compared to roads and facades, have less obstructed sky views. During the day, the higher sky view factor of roofs prevents the trapping of radiation within the urban texture, and ensures a better radiative cooling by night. Nevertheless, the high albedo approach and the application of `cool materials' are increasingly recommended for both urban roads (Akbari, Pomerantz, and Taha 2001; Alchapar, Correa, and Cantón 2014; Santamouris et al. 2012; Santamouris, Synnefa, and Karlessi 2011; Synnefa et al. 2011; Zinzi, Carnielo, and Fasano 2012) and facades (Bougiatioti et al. 2009; Doya, Bozonnet, and Allard 2012; Synnefa, Santamouris, and Apostolakis 2007). The goal of this study is to investigate the role of facade surface properties on the canopy layer microclimate in a dense urban context.
18.	Gál, Csilla V (författare) The influence of shade trees on the canopy layer microclimate within urban blocks : a numerical simulation study 2015 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Over the coming decades, many locatons are predicted to see warmer temperatures and more frequent extreme heat events as a result of climate change. Rising temperatures, coupled with the urban heat island effect, are expected to exacerbate existng conditons in cites. As a consequence, heat mitgaton in urban areas is antcipated be one of the key challenges of the twenty-first century. A frequently advocated means of mitgatng the urban heat island is through shade trees. Through the reducton of air and radiatve temperatures, they also improve the outdoor human thermal comfort and reduce building cooling loads. Utlizing four Hungarian metropolitan block typologies as cases, a numerical simulaton study is carried out to assess the impact of shade trees on the microclimate within urban blocks. The study applied ENVI-met for microclimate simulaton and MATLAB for the analysis and visualizaton of the results. Microclimate conditons within the blocks---with and without trees---are examined on the basis of diurnal air and mean radiant temperatures. Findings indicate that microclimate improvement by way of trees are primarily achieved through shading. The greatest reducton in daytme air and radiatve temperatures is achieved in configuratons with large open spaces, suggestng that effectve heat mitgaton strategies should also consider the interference between the shading of trees and buildings.
19.	Gál, Csilla V (författare) Urban design and building regulation changes in the transformation of the urban block : A design analysis though the lens of urban climatology in Budapest 2011 Ingår i: City Weathers. Konferensbidrag (refereegranskat)abstract Hungary witnessed limited climatic considerations in the practice of architecture and urban planning in the past. The omission of urban climate related issues was — and still is — essentially the outcome of the prevailing technocratic approach. This negligence, coupled with the growth in motor vehicle ownership, changing building design and air-conditioning practices, contributed to the the deterioration of the urban atmospheric environment over the last decades. The efforts to improve dwelling conditions over previous centuries, culminated in several waves of urban design and planning reforms. The outcome of these changing forces was the evolution of the Budapest urban block. During the twentieth century, its development followed the line described by Ernst May (‘from the block to the slab'), only to surpass it with hybrid forms in the twenty-first. This paper, focusing on the transformation of the Budapest urban block, sets forth to provide a historic cross section from the period of the city’s late industrialization to present day. The analysis of this process is facilitated though the identification and use of urban block typologies: each representing distinct urban design and regulatory paradigms. By reviewing the main forces that influenced the emergence of different urban block typologies, and subsequently, presenting an analysis of the resultant configurations, the author aims at introducing climatic considerations into urban design. Downtown urban blocks are at the center of this study, as they represent the most crucial section of the city. These blocks are not only exposed to the highest intensities of the urban heat island effect, but are also facing drear consequences due to the lack of urban green spaces. Because the study aims at addressing urban living and urban environmental concerns, the analysis is focused on existing metropolitan housing models. The first part of the paper presents the evolution of aesthetic, hygienic, structural and other concerns that contributed to the development of Budapest urban block, as well as, identifies the four developed typologies. The second part of the paper presents an analysis by juxtaposing the main regulatory principles and the resultant typologies, in an attempt to pinpoint measures that both effects micro-climate, as well as, are within the control of urban planning, design or architecture. The aim of this analysis is to bring forth the readily available regulatory measures that could become climate- sensitive design guidelines in the future. The outcome of this paper aims to inform policy makers, urban planners, architects and other building professionals regarding the necessity of the inclusion of climate- sensitive design principles into our current design and regulatory practices. In order to extend our understating of this subject -- regarding the casual relationship between urban design parameters and the resultant microclimates --, the author argues for further microclimatic investigations. These subsequent studies will clarify and support the emerging climate-sensitive urban design guidelines, which in turn could ameliorate the existing microclimatic conditions.
20.	Gál, Csilla V (författare) Urban greening and cool surfaces : the effectiveness of climate change adaptation strategies within the context of Budapest 2015 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Regional climate projections for Central and Eastern Europe indicate a rise in summertime temperatures along with an increase in the frequency of warm temperature extremes by the end of the next century. In the case of Hungary, models indicate a 1.7–2.6°C rise in summer temperatures in the near future, and a 3.5–6.0°C increase is projected for the end of the twenty-first century—based on the A1B scenario. Besides rising temperatures, long term projections also signal a 20–40% decrease in summer precipitation in Hungary. In Budapest, the existing urban heat island (UHI) intensity of 4–8°C is expected to make these already adverse projections worse. Since the combined influences of these phenomena will be most pronounced in the densely built and populated areas of the city, identifying effective UHI mitigation and climate change (CC) adaptation strategies for these ares is of primary importance. This paper investigates the impact of cool roofs and pavements along with the influence of different canopy cover ratios on the urban canopy layer (UCL) climate for a summer day, and assesses their impact on human thermal comfort under projected climate conditions at the pedestrian level. The goal is to evaluate the effectiveness of these popular CC adaptation actions and to contribute to the development of a systematic framework for the assessment of UHI mitigation strategies. The study took four dense urban configurations from Budapest—characteristic to most Central European cities—to examine the effectiveness of these approaches. The numerical simulation study utilizes ENVI-met and MATLAB. Preliminary results indicate that the performance of CC adaptation strategies is the function of the configurations' initial thermal performance. Consequently, the starting point of any adaptation proposals should be the evaluation of the initial thermal behavior of the selected focus area, followed by the selection of appropriate strategies—based on both the shortcomings of the initial local or microclimate, and the available opportunities for improvements. This study is a first attempt to quantify key CC adaptation strategies for Budapest. The results of this research will provide feedback to local authorities on the effectiveness of the assessed approaches and foster the articulation of more precise and economic CC adaptation actions and measures.
21.	Gál, Csilla V (författare) Urban weather generation : the intercomparison of three emerging models 2021 Konferensbidrag (refereegranskat)abstract Cities modify the background climate through the surface-atmosphere interaction. This modification is function of urban design features, such as the configuration of buildings and the amount of vegetation. Compared to the undisturbed climate of the region, the climate of cities is characterized by higher temperature and lower wind speed. This modification is especially pronounce in dense urban areas. The climate modification of cities is not static, but varies in space and time. The spatial variations are governed by land use and built form differences, as well as by the presence or absence of green and blue infrastructures. Due to the spatial complexity of cities and the general lack of urban weather station networks in most places, the amount of available urban weather data is limited. As a consequence, planners, engineers and public health professionals can only approximate the climate impact of built environments in their respective fields.Over the past years, several numerical simulation models have emerged that are able to model the influence of built areas on the atmosphere at the local scale and thus, deliver urban weather data for an area of interest. The aim of this study is to assess the performance of three numerical models with an ability to predict site-specific urban air temperature. The evaluated models are the Urban Weather Generator (UWG), the Vertical City Weather Generator (VCWG) and the Surface Urban Energy and Water Balance Scheme (SUEWS). Although the models differ in their scopes, modeling approaches and applications, they all derive the urban weather data from rural observations considering the land use and built form characteristics of the site.The models are evaluated against air temperature measurements from the dense, 13th District of Budapest (Hungary). The field measurement utilized simple air temperature and relative humidity loggers placed in non-aspirated solar radiation screens at four shaded sites. The two week measurement period encompassed a five-day-long anticyclonic period with clear sky and low wind speed. Preliminary results indicate a good general agreement between modeled and observed values with root mean square error below or at 2ºC and index of agreement between 0.92-0.96. During the anticyclonic period most models slightly overestimate the daily maximum and underestimated the daily minimum urban air temperature.
22.	Kántor, Noémi, et al. (författare) Human-biometeorological significance of shading in urban public spaces : Summertime measurements in Pécs, Hungary 2018 Ingår i: Landscape and Urban Planning. - : Elsevier. - 0169-2046 .- 1872-6062. ; 170, s. 241-255 Tidskriftsartikel (refereegranskat)abstract Shading is shown to be one of the most effective strategies to mitigate urban heat stress, especially on a small scale. This paper presents an empirical study investigating the effectiveness of different means of shading—by sun sails and trees—to improve the local thermal environment during the summer. Three different urban settings were investigated through detailed human-biometeorological measurements in the Hungarian city of Pécs. Our study employed the accurate six-directional radiation measurement technique, and calculated Physiological Equivalent Temperature (PET) from the obtained data to assess outdoor thermal conditions. Our results indicate that in open urban squares trees can mitigate heat stress more effectively than low-hanging sun sails, installed right above the head of pedestrians. In the period of 9:00–16:00, the average PET reduction by trees and low sun sails was 9.0 °C and 5.8 °C, respectively. Sun sails, installed at higher elevation to shade an entire street canyon, and mature trees with dense canopy had more pronounced heat stress reduction ability, and were able to reduce the local PET by over 10 °C. Our study demonstrates the importance of detailed small-scale field measurements, the outcomes of which can be incorporated into climate-responsive urban design strategies with ease.
23.	Kántor, Noémi, et al. (författare) Mikroklíma modellezés a városi közterülettervezés szolgálatában [Microclimate modeling at the service of urban public space design] 2017 Ingår i: Meteorológiai Tudományos Napok. 2017. November 23-24. Mikro- és mezoskálájú légköri folyamatok modellezése. Az előadások összefoglalói.. - Budapest, Hungary. - 9789639931145 Konferensbidrag (refereegranskat)abstract Európa lakosságának mintegy kétharmada már most is városi környezetben él, s a városi populáció aránya 2050-re várhatóan 80% fölé fog emelkedni. Mivel a városokra jellemző többlet hőmennyiség, valamint a városok csökkent átszellőzési képessége tovább súlyosbítják a klímaváltozással járó hőmérsékletemelkedést, a – várhatóan egyre gyakoribbá, hosszabbá és intenzívebbé váló – hőhullámok hatásai különösen a városlakók egészségét veszélyeztetik. Ennél fogva a nyári hőség káros következményeinek megelőzése a várostervezés egyik kiemelt feladata. A természet- alapú megoldások (Nature-Based Solutions, NBS) egy újonnan bevezetett fogalom a környezetkutatás és környezet- gazdálkodás területén, mely a klímaváltozással járó kihívások kezelésére természetes tényezőket, illetve folyamatokat ajánl. Ebben a tanulmányban – a négyéves Nature4Cities projekt keretein belül – a fás vegetáció hőstressz-mérséklő kapacitását vettük górcső alá egyrészt terepi mérések, másrészt numerikus szimulációk segítségével.A léghőmérséklet korántsem az egyedüli paraméter az emberi szervezet hőháztartása szempontjából. Sőt, számos humán-biometeorológiai tanulmány rámutatott már a sugárzási viszonyok vezető szerepére a nyári hőterhelés kialakulásában. Éppen ezért tanulmányunkban a biometeorológiai vizsgálatok kulcsparaméterére, az átlagos sugárzási hőmérsékletre (Mean Radiant Temperature, Tmrt), illetve ennek a fás vegetáció általi mérséklésére helyeztük a hangsúlyt.Tanulmányunk első részében három, a város-biometeorológia területén gyakran alkalmazott mikroklíma modellt (RayMan, ENVI-met, SOLWEIG) hasonlítottunk össze a tekintetben, hogy mennyire képesek a Tmrt valós értékeinek szimulálására. A modellellenőrzéshez egy derült égboltviszonyokkal jellemezhető késő nyári nap humán- biometeorológiai méréssorozatának adatait használtuk fel. A 26-órás mérés során a szegedi Bartók Béla tér öt különböző pontján rögzítettük a rövid-, és hosszúhullámú sugárzási mérleg komponenseket, hogy azokból a leghitelesebb biometeorológiai eljárás szerint Tmrt-t számoljunk. A három mikroklíma-modell közül a SOLWEIG szolgáltatta a leghitelesebb eredményeket, így később ezt a modellt használtuk arra, hogy összehasonlítsuk különféle fásítási szcenáriók hőstressz-mérséklő hatását – ugyancsak a szegedi Bartók Béla téri mintaterületen. A szimulációk alapján a lombkorona transzmisszivitásának (sugárzásáteresztő képességének) változtatása kisebb, míg azonos korona-térfogat mellett a lombkorona méretének (több kis fa vs. kevesebb nagyobb fa), valamint a fák területen belüli elrendezésének változtatása (egyenletesen vs. csak az épülethomlokzatok mentén ültetett fák) jelentősebb Tmrt módosítást eredményezett.
24.	Kántor, Noémi, et al. (författare) Relevance of urban trees and sun shades regarding summertime heat stress reduction – a field surveys from Pécs, Hungary 2017 Konferensbidrag (refereegranskat)abstract Mitigating the impact of summertime heat stress became the central issue of climate-conscious urban planning as a result of rising temperatures and continued urbanization trends. Furthermore, recent EU planning directives gave priority to nature-based solutions (NBS) and hence to re-naturing cities. Within the scope of the international Nature4Cities project fostering the use such solution, an inter- and cross-disciplinary research will be done assessing the performance of archetypal NBSs addressing different urban challenges – in this case, heat mitigation in urban environments.The objective of this particular study is to compare the effectiveness of natural and artificial shading solutions (urban trees and sun sails) in reducing summertime heat stress and enhancing outdoor thermal comfort of pedestrians. The Physiological Equivalent Temperature (PET), used as performance indicator in this study, was calculated from field data. The measurement campaign utilizing two human-biometeorological stations recorded pedestrian-level radiant flux densities from six perpendicular directions, air temperature, relative humidity and wind speed on three late-summer days. The daytime measurements were conducted at three different urban settings in Pécs, a medium-size Central-European city.Our research found that mature trees with dense canopy have the highest heat stress reduction potential and could reduce the local PET by up to 10°C. Even though artificial sun sails blocked effectively direct solar exposure, the low-hanging sun sails became the sources of long-wave radiation which made the thermal comfort conditions below them somewhat worse compared to trees. Our study demonstrates the importance of small-scale field measurements, the outcomes of which are directly applicable in the climate-adaptive design of urban spaces.
25.	Kántor, Noémi, et al. (författare) The impact of façade orientation and vegetation on summer heat stress – measurements and simulations from a rectangular Central-European square 2017 Konferensbidrag (refereegranskat)abstract Around three quarter of the European population already lives in urban areas and by 2050 this proportion isexpected to rise over 80%. Since climate change is expected to bring rising temperatures and more frequent heatwaves, mitigating the impact of extreme heat events is one of the most important issues in urban planning. Nature-Based Solutions (NBS) is a recently introduced concept in environmental research and management that promotesnature as a means to address the challenges brought about climate change. Researches of human-biometeorologydemonstrated that radiation heat load, quantified as mean radiant temperature (Tmrt), is the main source ofdaytime heat stress in summer. In European cities—especially in those with dense historic urban cores—carefullyplanned and properly maintained shade trees constitute the most effective NBS for mitigating extreme thermalconditions, while also offering several co-benefits.This study was conducted with the following two aims: (a) to assess the impact of woody vegetation anddifferent façade orientation on the radiation heat load in a complex urban setting; and (b) to evaluate the performanceof SOLWEIG, a radiation model, in reproducing the measured short- and long-wave radiation flux densities.The observation was conducted over a 26-hour long period at the rectangular Bartók Square in Szeged (Hungary)on a clear and warm late-summer day. The investigation utilized two tailor-made human-biometeorologicalstations equipped with rotatable net radiometers. The model–measurement comparison is based on data collectedfrom five locations within the square: from the center and from four sites next to the bordering façades.The measurements confirmed that on clear summer days Tmrt can reach extreme level at exposed locations(65–75C). However, shade trees are able to reduce daytime Tmrt to 30–35C. Shading SE-, S- and SW-facingfaçades and adjacent sidewalks is extremely important for the reduction of pedestrian heat stress and thus, therisk of heat stroke. When a measurement point adjacent to a facade became exposed to direct solar radiation,the radiation load increased significantly due to the additional lateral components—the reflected short-wave andthe emitted long-wave fluxes—emanating from the wall. In this respect, SOLWEIG was unable to reproducethe prolonged heat emitting effect of walls following solar exposure. Additionally, the measurement–modelcomparison revealed minor inconsistencies that originated from the model’s treatment of tree crowns: representingthem as perfectly shaped and homogeneous bodies. Due to this simplification, the observed brief penetrations ofdirect sunbeams through the canopy at most locations were not reproduced.
26.	Kántor, Noémi, et al. (författare) The impact of façade orientation and woody vegetation on summertime heat stress patterns in a Central-European square : comparison of radiation measurements and simulations 2018 Ingår i: Advances in Meteorology. - : Hindawi Publishing Corporation. - 1687-9309 .- 1687-9317. Tidskriftsartikel (refereegranskat)abstract Increasing summertime air temperature deteriorates human health especially in cities where the warming tendency is exacerbated by urban heat island. Human-biometeorological studies shed light on the primary role of radiation conditions in the development of summertime heat stress. However, only a limited number of field investigations have been conducted up to now. Based on a 26-hour long complex radiation measurement this study presents the evolved differences within a medium-sized rectangular square in Szeged, Hungary. Besides assessing the impact of woody vegetation and façade orientation on the radiation heat load, different modeling software (ENVI-met, SOLWEIG, RayMan) are evaluated in reproducing mean radiant temperature (Tmrt).Although daytime Tmrt can reach extreme level at exposed locations (65–75°C) mature shade trees can reduce it to 30–35°C. Nevertheless, shading from buildings adjacent to sidewalks plays also an important role in mitigating pedestrian heat stress. Sidewalks facing to SE, S and SW do not benefit from the shading effect of buildings therefore shading them by trees or artificial shading devices is of high importance. The measurement–model comparison revealed smaller or larger discrepancies that raise awareness on the careful adaptation of any modeling software and on the relevance of fine-resolution field measurements.
27.	Kovács, Attila, et al. (författare) Adjustment of the thermal component of two tourism climatological assessment tools using thermal perception and preference surveys from Hungary 2016 Ingår i: Journal of Theoretical and Applied Climatology. - : Springer Vienna. - 0177-798X .- 1434-4483. ; 125:1-2, s. 113-130 Tidskriftsartikel (refereegranskat)abstract This study introduces new methodological concepts for integrating seasonal subjective thermal assessment patterns of people into the thermal components of two tourism climatological evaluation tools: the Tourism Climatic Index (TCI) and the Climate-Tourism/Transfer-Information-Scheme (CTIS). In the case of the TCI, we replaced the air temperature and relative humidity as the basis of the initial rating system with the physiologically equivalent temperature (PET)—a complex human biometeorological index. This modification improves the TCI’s potential to evaluate the thermal aspects of climate. The major accomplishments of this study are (a) the development of a new, PET-based rating system and its integration into the thermal sub-indices of the TCI and (b) the regionalization of the thermal components of CTIS to reflect both the thermal sensation and preference patterns of people. A 2-year-long (2011–2012) thermal comfort survey conducted in Szeged, Hungary, from spring to autumn was utilized to demonstrate the implementation of the introduced concepts. We found considerable differences between the thermal perception and preference patterns of Hungarians, with additional variations across the evaluated seasons. This paper describes the proposed methodology for the integration of the new seasonal, perception-based, and preference-based PET rating systems into the TCI, and presents the incorporation of new PET thresholds into the CTIS. In order to demonstrate the utility of the modified evaluation tools, we performed case study climate analyses for three Hungarian tourist destinations. The additional adjustments introduced during the course of those analyses include the reduction of TCI’s temporal resolution to 10-day intervals and the exclusion of nocturnal and winter periods from the investigation.
28.	Liu, G, et al. (författare) A review of air filtration technologies for sustainable and healthy building ventilation 2017 Ingår i: Sustainable cities and society. - : Elsevier. - 2210-6707. ; 32, s. 375-396 Tidskriftsartikel (refereegranskat)abstract Urbanization increased population density in cities and consequently leads to severe indoor air pollution. As a result of these trends, the issue of sustainable and healthy indoor environment has received increasing attention. Various air filtration techniques have been adopted to optimize indoor air quality. Air filtration technique can remove air pollutants and effectively alleviate the deterioration of indoor air quality. This paper presents a comprehensive review on the synergistic effect of different air purification technologies, air filtration theory, materials and standards. It evaluated different air filtration technologies by considering factors such as air quality improvement, filtering performance, energy and economic behaviour, thermal comfort and acoustic impact. Current research development of air filtration technologies along with their advantages, limitations and challenges are discussed. This paper aims to drive the future of air filtration technology research and development in achieving sustainable and healthy building ventilation.
29.	Pan, Song, et al. (författare) Cluster analysis for occupant-behavior based electricity load patterns in buildings : a case study in Shanghai residences 2017 Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-3599 .- 1996-8744. ; 10:6, s. 889-898 Tidskriftsartikel (refereegranskat)abstract In building performance simulation, occupant behavior contributes to large uncertainties, which often lead to considerable discrepancies between actual energy consumption and simulation results. This paper aims to extract occupant-behavior related electricity load patterns using classical K-means clustering approach at the initial investigation stage. Smart-metering data from a case study in Shanghai, China, was used for the load pattern analysis. The electricity load patterns of occupants were examined on a daily/weekly/seasonal basis. According to their load patterns, occupants were categorized as (a) white-collar workers, (b) poor or older families and (c) rich or young families. The daily patterns indicated that electricity use was much more random and fluctuated over a wide range. Most households of the monitored communities consumed relatively-low electricity; the characteristic double peak with higher level of consumption in the morning and evening were only apparent in a relatively small subset of residents (mostly white-collar workers). The weekly analysis found that significant load shifting towards weekend days occurred in the poor or old family group. The electricity saving potential was greatest in the white-collar workers and the rich or young family groups. This study concludes with recommendations to stakeholders utilizing our load profiling results. The research provides a rare insight into the electricity-use-related occupant behaviors of Shanghai residents through the case study of two communities. The findings of the study are also presented in a meaningful way so that they can directly aid the decision-making of governments and other stakeholders interested in energy efficiency. The research results are also relevant to the building energy simulation community as they are derived from observations, and thus can have the potential to improve the efficiency and accuracy of numerical simulation results.
30.	Takács, Ágnes, et al. (författare) Radiation conditions at a Central European square in a hot summer day, a case study from Szeged, Hungary 2017 Ingår i: 97th Annual Meeting of the American Meteorological Society (AMS) jointly with the 13th Symposium on the Urban Environment, Seattle, WA. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract In the light of sustained urbanization and rising temperature trends, mitigating the impact of extreme heat events is a pressing urban planning issue. Radiation heat load, quantified as mean radiant temperature (Tmrt), has been identified as the main source of summer heat stress. Several studies ascertained that Tmrt is the key factor driving human thermal comfort in outdoor urban places. Shading that reduces radiation heat load (Tmrt) is the most effective means to mitigate heat stress in outdoor public places, which offer a venue for leisure, recreation and for the social life of residents. Nonetheless, the small-scale thermal conditions of urban places are not only governed by shade trees and greenery, but also by buildings and paved surfaces. The aim of this study is twofold. First, it assesses the impact of differently oriented street facades with varying solar exposure on the human radiation balance at a medium-sized square in a mid-latitude city. Second, it evaluates the performance of popular, freely available microclimate and radiation models in deriving Tmrt values. The well-vegetated, rectangular Bartók square was selected in Szeged, Hungary to calculate various radiation parameters using three numerical simulation models (ENVI-met, SOLWEIG and RayMan). The derived parameters (radiation flux densities from different directions, as well as Tmrt) are compared with corresponding values obtained from detailed on-site measurements. The field data are collected as part of a 24-hour long radiation measurement utilizing the six-directional method, where a set of pyranometers and pyrgeometers are used to record short- and long-wave flux densities from six perpendicular directions (from above, from below as well as from the four cardinal points). The model-measurement comparison is based on hourly data from five locations within the square: from the center and from near the four bordering street facades of the rectangular square. Our initial results indicate that besides direct solar radiation, the temperatures of artificial surfaces (e.i. of building walls and pavements) strongly influences the human radiation balance: the increased temperature of surrounding surfaces increases the amount of emitted long-wave radiation and thus, reduces the amount a person is able to dissipate. Investigations like ours are necessary both for the advancement of our filed in general, and for the development of numerical models in particular. Models are simplifications of reality and thus they introduce a certain degree of idealization: trees are never as perfectly shaped or have a homogeneous crown transmissivity and leaf area index (LAI) in the reality, neither do surface parameters are as uniform as frequently assumed by models. All these differences influence model results to a certain degree. Therefore, the ideal outdoor thermal conditions that practitioners often plan for from behind their desks are likely to be worse in reality. Identifying the strengths and weaknesses of different models and revealing how they compare to reality is essential for both scientists and urban planners, since they all need to understand and acknowledge the limitations of the numerical approach.
31.	Zhang, Xingxing, et al. (författare) A review of urban energy systems at building cluster level incorporating renewable-energy-source (RES) envelope solutions 2018 Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 230, s. 1034-1056 Tidskriftsartikel (refereegranskat)abstract The emergence of renewable-energy-source (RES) envelope solutions, building retrofit requirements and advanced energy technologies brought about challenges to the existing paradigm of urban energy systems. It is envisioned that the building cluster approach—that can maximize the synergies of RES harvesting, building performance, and distributed energy management—will deliver the breakthrough to these challenges. Thus, this paper aims to critically review urban energy systems at the cluster level that incorporate building integrated RES solutions. We begin with defining cluster approach and the associated boundaries. Several factors influencing energy planning at cluster scale are identified, while the most important ones are discussed in detail. The closely reviewed factors include RES envelope solutions, solar energy potential, density of buildings, energy demand, integrated cluster-scale energy systems and energy hub. The examined categories of RES envelope solutions are (i) the solar power, (ii) the solar thermal and (iii) the energy-efficient ones, out of which solar energy is the most prevalent RES. As a result, methods assessing the solar energy potentials of building envelopes are reviewed in detail. Building density and the associated energy use are also identified as key factors since they affect the type and the energy harvesting potentials of RES envelopes. Modelling techniques for building energy demand at cluster level and their coupling with complex integrated energy systems or an energy hub are reviewed in a comprehensive way. In addition, the paper discusses control and operational methods as well as related optimization algorithms for the energy hub concept. Based on the findings of the review, we put forward a matrix of recommendations for cluster-level energy system simulations aiming to maximize the direct and indirect benefits of RES envelope solutions. By reviewing key factors and modelling approaches for characterizing RES-envelope-solutions-based urban energy systems at cluster level, this paper hopes to foster the transition towards more sustainable urban energy systems.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Resultat 1-31 av 31

Avgränsa träffmängd

Typ av publikation: konferensbidrag (20); tidskriftsartikel (10); doktorsavhandling (1)

Typ av innehåll: refereegranskat (21); övrigt vetenskapligt/konstnärligt (9); populärvet., debatt m.m. (1)

Författare/redaktör: Gál, Csilla V (31); Kántor, Noémi (9); Gulyas, Agnes (7); Unger, János (4); Zhang, Xingxing (3); Lelovics, Enikő (2); visa fler...; Chen, X. (1); Liu, L. (1); Xiao, M. (1); Pan, S. (1); Wu, J (1); Liu, G (1); Tang, L. (1); Feng, Tao (1); Widén, Joakim, 1980- (1); Han, Mengjie (1); Wang, Xinru (1); Pan, Song (1); Chen, Liang (1); Nice A., Kerry (1); Land, Peter (1); Gal, Tamas (1); Yan, Da (1); Wu, Jinshun (1); Lovati, Marco (1); Kovács, Attila (1); Savić, Stevan (1); Gál, Tamás Mátyás (1); Milosevic, Dragan (1); Markovic, Vladimir (1); Arsenovic, Daniela (1); Clements-Croome, D (1); Liu, Jiaping (1); Wei, Yixuan (1); Rend, Guangying (1); Yong, Shi (1); Takács, Ágnes (1); Kiss, Márton (1); Vigna, Ilaria (1); visa färre...

Lärosäte: Högskolan Dalarna (31); Uppsala universitet (1)

Språk: Engelska (29); Ungerska (2)

Forskningsämne (UKÄ/SCB): Naturvetenskap (27); Teknik (3); Humaniora (3)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

LIBRIS.kb.se

Stäng

Kopiera och spara länken för att återkomma till aktuell vy