Urban Microclimate Analysis for High Performance Office Buildings

<p>This research explored whether urban microclimate analysis has significant impacts on high-performance office buildings. It studied the effects of detailed three-dimensional urban microclimate modelling on building performance simulation. The feasibility and necessity of developing an urban microclimate simulation system were explored. Currently, individual parameters of urban microclimate are modelled by individual programs. However, there was no individual software that could model airflow, Urban Heat Island (UHI) effects and building energy performance at the same time. A simulation system made it possible to model these features of urban microclimate together. Apart from the reliability of programs, accessibility and compatibility were also important for building a simulation system. The goal of this research was to determine the relative scale of the likely microclimate impacts on energy performance, not to present a system that made a precise estimate of these effects in combination. The scale of the variations of results due to changes of urban microclimate parameters were more significant than the values of the results themselves. This is because the focus of the research was on determining to what degree each parameter made a difference in the building performance. The goal was to determine whether it is necessary to model every urban microclimate parameter when their individual effects are combined. The parameters of urban microclimates included horizontal parameters like urban wind and UHI, and vertical parameters like lapse rate, urban boundary layer. In this research, the urban microclimate was modelled in three dimensions, but the process of urban microclimate modelling was time-consuming. This leaded to one of the central questions of the thesis: is there value in the time spent? How big is the scale of the influence of urban microclimate detailed modelling on the prediction of building performance? Is it worthwhile to model three-dimensional urban microclimates? When there is not enough time to calibrate all parameters, what are the parameters’ priorities? A prototypical high-rise office building was modelled based on the data about high-rise office buildings in London. Firstly, the effects of the horizontal parameters were explored. The UHI has larger effects than urban wind. Secondly, the significance of vertical parameters was also explored. At a lower floor, the influence of the wind speed exponent and the boundary layer thickness on building performance simulation is bigger than that of the air temperature gradient coefficient. However, at a higher floor, the influence of the air temperature gradient coefficient is bigger. Finally, a multilayer modelling method was developed to explore the inconsistent vertical variations. The multilayer model consists of the portion in the Urban Canopy Layer (UCL) and the portion in the Urban Boundary Layer (UBL). The effects of vertical variations increase with the distance between the studied height and the UCL height. The feasibility and necessity of developing the simulation system of urban microclimate detailed modelling were demonstrated in the climate of London. In different climates, is it still necessary? The effects of urban microclimate detailed modelling on windy, continental, and tropical climates were also studied. The necessity of urban microclimate detailed modelling has been demonstrated because the combined effects produced around -25% change in London’s climate and Wellington’ climate at most. In Beijing’s climate the change was around -6% and in Singapore’s climate was 2.2% at most. The UHI has a big impact in moderate and continental climates. In a continental climate, there is a big difference in the monthly thermal load prediction. It helps engineers optimize the design of heating in winter and cooling in summer. The effects of urban wind in a windy climate are bigger than those in other cities. The precision of vertical variations has very limited influence, especially in the tropical climate. The air temperature gradient in a tropical climate changed thermal load prediction a lot. The parameters’ priorities in different climates are different. There is no consistent pattern of one factor being less important than the others across all these climates. Therefore, to model the thermal performance of tall buildings in dense urban environments it is necessary to develop a simulation system that can model the Urban Heat Island, and the differences in 3D of variations of temperature, sun and wind within and above the Urban Canopy Layer. Finally, from the one case study examined, modelling urban microclimate in detail is more important for natural ventilation systems than for HVAC systems. Overall, the simulation system of urban microclimate modelling was developed gradually. It is necessary to develop the simulation system to approach a real urban circumstance. The accuracy of the detailed urban microclimate model depends on the engineers’ requirements. The priority of urban microclimate parameters depends on climatic features.</p>

Urban Microclimate Analysis for High Performance Office Buildings

<p>This research explored whether urban microclimate analysis has significant impacts on high-performance office buildings. It studied the effects of detailed three-dimensional urban microclimate modelling on building performance simulation. The feasibility and necessity of developing an urban microclimate simulation system were explored. Currently, individual parameters of urban microclimate are modelled by individual programs. However, there was no individual software that could model airflow, Urban Heat Island (UHI) effects and building energy performance at the same time. A simulation system made it possible to model these features of urban microclimate together. Apart from the reliability of programs, accessibility and compatibility were also important for building a simulation system. The goal of this research was to determine the relative scale of the likely microclimate impacts on energy performance, not to present a system that made a precise estimate of these effects in combination. The scale of the variations of results due to changes of urban microclimate parameters were more significant than the values of the results themselves. This is because the focus of the research was on determining to what degree each parameter made a difference in the building performance. The goal was to determine whether it is necessary to model every urban microclimate parameter when their individual effects are combined. The parameters of urban microclimates included horizontal parameters like urban wind and UHI, and vertical parameters like lapse rate, urban boundary layer. In this research, the urban microclimate was modelled in three dimensions, but the process of urban microclimate modelling was time-consuming. This leaded to one of the central questions of the thesis: is there value in the time spent? How big is the scale of the influence of urban microclimate detailed modelling on the prediction of building performance? Is it worthwhile to model three-dimensional urban microclimates? When there is not enough time to calibrate all parameters, what are the parameters’ priorities? A prototypical high-rise office building was modelled based on the data about high-rise office buildings in London. Firstly, the effects of the horizontal parameters were explored. The UHI has larger effects than urban wind. Secondly, the significance of vertical parameters was also explored. At a lower floor, the influence of the wind speed exponent and the boundary layer thickness on building performance simulation is bigger than that of the air temperature gradient coefficient. However, at a higher floor, the influence of the air temperature gradient coefficient is bigger. Finally, a multilayer modelling method was developed to explore the inconsistent vertical variations. The multilayer model consists of the portion in the Urban Canopy Layer (UCL) and the portion in the Urban Boundary Layer (UBL). The effects of vertical variations increase with the distance between the studied height and the UCL height. The feasibility and necessity of developing the simulation system of urban microclimate detailed modelling were demonstrated in the climate of London. In different climates, is it still necessary? The effects of urban microclimate detailed modelling on windy, continental, and tropical climates were also studied. The necessity of urban microclimate detailed modelling has been demonstrated because the combined effects produced around -25% change in London’s climate and Wellington’ climate at most. In Beijing’s climate the change was around -6% and in Singapore’s climate was 2.2% at most. The UHI has a big impact in moderate and continental climates. In a continental climate, there is a big difference in the monthly thermal load prediction. It helps engineers optimize the design of heating in winter and cooling in summer. The effects of urban wind in a windy climate are bigger than those in other cities. The precision of vertical variations has very limited influence, especially in the tropical climate. The air temperature gradient in a tropical climate changed thermal load prediction a lot. The parameters’ priorities in different climates are different. There is no consistent pattern of one factor being less important than the others across all these climates. Therefore, to model the thermal performance of tall buildings in dense urban environments it is necessary to develop a simulation system that can model the Urban Heat Island, and the differences in 3D of variations of temperature, sun and wind within and above the Urban Canopy Layer. Finally, from the one case study examined, modelling urban microclimate in detail is more important for natural ventilation systems than for HVAC systems. Overall, the simulation system of urban microclimate modelling was developed gradually. It is necessary to develop the simulation system to approach a real urban circumstance. The accuracy of the detailed urban microclimate model depends on the engineers’ requirements. The priority of urban microclimate parameters depends on climatic features.</p>

Kinematics or Kinetics: Optimum Measurement of the Vertical Variations of the Center of Mass during Gait Initiation

Background: During gait, the braking index represents postural control, and consequently, the risk of falls. Previous studies based their determination of the braking index during the first step on kinetic methods using force platforms, which are highly variable. This study aimed to investigate whether determining the braking index with a kinematic method, through 3D motion capture, provides more precise results. Methods: Fifty participants (20 to 40 years) performed ten trials in natural and fast gait conditions. Their braking index was estimated from their first step simultaneously using a force platform and VICON motion capture system. The reliability of each braking index acquisition method was assessed by intraclass correlation coefficients, standard error measurements, and the minimal detectable change. Results: Both kinetic and kinematic methods allowed good to excellent reliability and similar minimum detectable changes (10%). Conclusion: Estimating the braking index through a kinetic or a kinematic method was highly reliable.

Structural Interpretation of Seismic Data of Mishrif Formation in East Abu-Amoud Field, South-eastern Iraq

The seismic method depends on the nature of the reflected waves from the interfaces between layers, which in turn depends on the density and velocity of the layer, and this is called acoustic impedance. The seismic sections of the East Abu-Amoud field that is located in Missan Province, south-eastern Iraq, were studied and interpreted for updating the structural picture of the major Mishrif Formation for the reservoir in the Abu-amoud field. The Mishrif Formation is rich in petroleum in this area, with an area covering about 820 km2. The seismic interpretation of this study was carried out utilizing the software of Petrel-2017. The horizon was calibrated and defined on the seismic section with well-logs data (well tops, check shot, sonic logs, and density logs) in the interpretations process for identifying the upper and lower boundaries of Mishrif Formation. As well, mapping of two-way time and depth structural maps was carried out, to aid in understanding the lateral and vertical variations and to show the formation of the structural surfaces. The study found that Mishrif thickness increases toward the east, which means that it increases from the Abu-Amoud field in Nasiriyah towards the East Abu-Amoud field in Missan province. The aim of the study is to draw a high-resolution structural image of the East Abu Amoud field in southeast Iraq and to show the types of the existing faults and structures in the study area.

Multiscale nonlinear inversion of gravity data for depth-to-basement estimation via coupled stochastic-deterministic optimization

We have developed a multiscale approach for solving 2D and 3D nonlinear inverse problems of gravity data in estimating the basement topography. The inversion is carried out in two stages in which the long-wavelength features of the basement are first estimated from smoothed gravity data via a stochastic optimization algorithm. The solution of this stage is used as the starting model for a deterministic optimization algorithm to reconstruct the short-wavelength features from the full-spectrum gravity data. The forward problem is capable of handling lateral and vertical variations in the density of sediments. Two cases are considered regarding prior knowledge about the density: (1) The density contrast between sediments at the surface and the underlying basement and its vertical variations are a priori known, and (2) only the density contrast at the surface is known with its vertical gradient to be recovered in the inversion. In the former case, the unknowns of the problem are the depths, whereas in the latter case, they are the depths and density gradients defined individually for each prism. Therefore, the inverse problem is ill-posed and has many local minima. The stochastic optimization algorithm uses a random initial model and estimates a coarse model of the basement topography. By repeating the stochastic inversion, an ensemble of solutions is formed defining an equivalent domain in the model space supposed to be within the neighborhood of the global minimum of which several starting solutions are extracted for the secondary deterministic inversion. The presented methodology has been tested successfully in converging to the global minima in 2D and 3D cases with 50 and 2352 total number of prisms, respectively. Finally, the inversion algorithm is used to calculate the thickness of the sediments in the South Caspian Basin using the EIGEN-6c4 global gravity model.

Spatial Distributions of 226Ra and 228Ra in the Indian and Southern Oceans in 2020 and Their Implications for Unique Currents

We examined the spatial variations in 226Ra and 228Ra concentrations from the surface to a depth of 830 m in the Indian and Southern Oceans during December 2019–January 2020. Notably, 226Ra concentrations at the surface increased sharply from 30°S to 60°S along an ~55°E transect (1.4 to 2.9 mBq/L), exhibiting small vertical variations, while 228Ra became depleted, particularly in the Southern Ocean. These distributions indicated the ocean-scale northward lateral movements of 226Ra-rich and 228Ra-depleted currents originating from the Antarctic Circumpolar Current (ACC). Using 226Ra concentrations, the fractions of the ACC at depths of 0–800 m were estimated to decrease from 0.95 to 0.14 from 60°S to 30°S through 0.56 at 43°S. The fractions in the subantarctic area the western Indian Ocean were higher than those previously reported from the eastern, indicating the preferential transport of the ACC. The fractions obtained were approximately equivalent to those in the western Indian section in the 1970s. This could be attributed to the minimal effects of the southward shift of the polar front due to global warming over the last 40 y, implying no notable changes in soluble material transport systems from the Southern Ocean to southern Indian Ocean.

Advanced Determination of Heat Flow Density on an Example of a West Russian Oil Field

Reliable geothermal data are required for basin and petroleum system modeling. The essential shortcomings of the methods and results of previous geothermal investigations lead to a necessity to reappraise the data on the thermal properties and heat flow. A new, advanced experimental basis was used to provide reliable data on vertical variations in the thermal properties of formation and heat flow for the area surrounding a prospecting borehole drilled through an unconventional hydrocarbon reservoir of the Domanik Formation in the Orenburg region (Russia). Temperature logging was conducted 12.5 months after well drilling. The thermal properties of the rocks were measured with continuous thermal core profiling on all 1699 recovered core samples. Within non-cored intervals, the thermal conductivity of the rocks was determined from well-logging data. The influence of core aging, multiscale heterogeneity and anisotropy, in situ pressure and temperature on the thermal properties of rock was accounted for. The terrestrial heat flow was determined to be 72.6 ± 2.2 mW·m−2—~114% larger than the published average data for the studied area. The experiment presents the first experience of supporting basin modeling in unconventional plays with advanced experimental geothermal investigations.