Outdoor comfort simulation of complex architectural designs: a review of simulation tools from the designer perspective.

The expanding design interest in outdoor comfort design is today supported by a few software tools. Given their different user-friendliness, modelling environments and simulation engines, a rational inquiry is how they are integrated into the digital design flow of architects and urban planners, which may include complex forms developments. Preliminary work is conducted to select architect-friendly tools that support the analysis of urban microclimate. A minimum set of criteria (amongst them the use of 3D models, the capability of calculating Mean Radiant Temperature and visual graphical outputs) led to the pre-selection of CitySim Pro, ENVI-met, Autodesk Thermal CFD, Grasshopper plug-ins Honeybee / Ladybug. The complex modelling experiment is conducted by simulating the outdoor thermal comfort of the space underneath the Rolex Learning Centre in Lausannewith each of the tools above. The paper describes and compares the principles, the procedures and the resources needed to prepare sound models that reduce the time of computation without compromising the quality of results. The potential applicability of tools in design is finally discussed from a user’s point of view. The tools’ capability of creating a 3D complex geometric model, or of importing one from a typical architectural tool, such as Rhino, is studied. Furthermore, it is debated how models can be used in the broader digital environment

Assessing heat-related health risk in Europe via the Universal Thermal Climate Index (UTCI)

In this work the potential of the Universal Thermal Climate Index (UTCI) as a heat-related health risk indicator in Europe is demonstrated. The UTCI is a bioclimate index that uses a multi-node human heat balance model to represent the heat stress induced by meteorological conditions to the human body. Using 38 years of meteorological reanalysis data, UTCI maps were computed to assess the thermal bioclimate of Europe for the summer season. Patterns of heat stress conditions and non-thermal stress regions are identified across Europe. An increase in heat stress up to 1°C is observed during recent decades. Correlation with mortality data from 17 European countries revealed that the relationship between the UTCI and death counts depends on the bioclimate of the country, and death counts increase in conditions of moderate and strong stress, i.e. when UTCI is above 26°C and 32°C. The UTCI’s ability to represent mortality patterns is demonstrated for the 2003 European heatwave. These findings confirm the importance of UTCI as a bioclimatic index that is able to both capture the thermal bioclimatic variability of Europe, and relate such variability with the effects it has on human health

Correlation of urban built form, density and energy performance

In order to optimize the energy consumption in cities and enhance the potential of using renewable energy sources, the form of the city is considered as an influential factor. Numerous indicators have been used to analyse the effect of density and other characteristics of urban form on energy use. The paper presents results of an investigation into the relationships of building energy performance with two important urban density indicators, namely site coverage and volume-area ratio. Generic mathematical model of pavilion urban built form has been developed in order to compare and contrast its land-use/density characteristics with energy performance. Energy analysis has been performed on geometrical models using urban simulation software. The relationship between energy and density indicators are compared by considering an important variables, namely plan depth, cut-off angle and number of storeys. The city of London, representing a temperate climate, is considered as a case study. According to the results, high-rise buildings with deeper plans achieve higher energy efficiency. However, in case of including PV energy generation, low-rise buildings with deeper plans illustrate better total energy performance. Graphical results provide urban planning guidelines that can be used by urban designers, planners and architects to facilitate the most energy-efficient built form density for promoting more sustainable cities

Fractional damping effects on the transient dynamics of the Duffing oscillator

We consider the nonlinear Duffing oscillator in presence of fractional damping which is characteristic in different physical situations. The system is studied with a smaller and larger damping parameter value, that we call the underdamped and overdamped regimes. In both we have studied the relation between the fractional parameter, the amplitude of the oscillations and the times to reach the asymptotic behavior, called asymptotic times. In the overdamped regime, the study shows that, also here, there are oscillations for fractional order derivatives and their amplitudes and asymptotic times can suddenly change for small variations of the fractional parameter. In addition, in this latter regime, a resonant-like behavior can take place for suitable values of the parameters of the system. These results are corroborated by calculating the corresponding Q-factor. We expect that these results can be useful for a better understanding of fractional dynamics and its possible applications as in modeling different kind of materials that normally need complicated damping terms. (c) 2022 Elsevier B.V. All rights reserved

Introducing a hybrid energy-use model at the urban scale: The case study of turin (Italy)

As in the past, the urban morphology plays an important role for the liveability of the city and for both outdoor and indoor human comfort. Nowadays, the relationship between the urban form and energy consumption has been estimated by many researchers, showing how the morphological aspects influence the energy consumption of the buildings, the thermal comfort of the urban spaces and the district air quality. Conversely, in recent urban planning processes, these morphological aspects are undervalued or no more considered. To reinforce their importance, this paper presents an optimization of a previous statistical model made by the complementary use of bottom-up and top-down models to evaluate the energy-use for residential buildings. The average intensity of energy-use data for residential buildings with different age, shape and heated volume has been corrected using the urban energy modelling tool CitySim Pro. This hybrid approach describes how the urban form, the solar exposure of buildings, the outdoor spaces and the material characteristics of urban surfaces impact on the energy performance of buildings. This research analyzed a case-study in the city of Turin (Italy) to quantify the space heating energy-use of residential buildings. To estimate the buildings heating energy-use, the urban energy simulation tool CitySim Pro was used, and the building information model of Turin was validated with the real consumptions data using two years of monitoring data. The results of this research show a direct correlation between the buildings energyuse and the following five urban variables: Building Coverage Ratio, Aspect ratio, Main Orientation of the Streets, Solar factor and albedo coefficients of outdoor surfaces. The building density and the urban canyon phenomenon play an important role, reducing the heating energy-demand in medium density urban contexts. Furthermore, the solar exposure strongly influences energy demands, especially for high buildings density contexts, as well as the presence of green surfaces.The proposed methodology, based on a multivariate compensative approach, can support urban planning to improve the energy sustainability of the cities