Computing Energy Performance of Building Density, Shape and Typology in Urban Context

AbstractThis paper aims to better understand the impact of urban context on building energy consumption. The factors of external shading, shapes generated from zoning ordinances, and local climate are examined concerning three main questions: (1) how density influences building energy consumption generally, (2) how a given density generates alternative building shapes that have different impacts on energy performance, and (3) how different typologies affect the energy-density relationship. To answer them, a series of parametric simulation experiments are conducted based on Martin and March's urban block structure. For more than 14,000 hypothetical models located at the Portland urban grid, the energy consumptions for the purposes of cooling and heating are simulated using AutoCAD script, MATLAB and Energy Plus 8. The results suggest that, different from the common perceptions, building energy consumptions for cooling and heating purposes do not always have a negative relationship with density. Instead, the energy consumption has a negative relationship with density before a turning point, and then the relationship changes to be positive. Also with the same FAR, different building cover ratio and typologies can lead to large variations in energy consumption. By the experiments on different building shapes generated by urban frit, it was found that even with the same typology, the building energy consumption can still vary significantly. Finally, the exploration of climate factors indicates that in both Portland and Atlanta, the findings are similar except that the energy-density relationship is weaker in Atlanta than in Portland

A GIS-based Energy Balance Modeling System for Urban Solar Buildings

AbstractSolar buildings as one type of decentralized renewable energy systems have been widely adopted to reduce carbon emissions. Related policy making faces two questions: how much total solar energy can be produced in a city and what proportion of building energy use can be supplied by the solar power? These questions remain hard to answer because of the lack of appropriate modeling systems, due to the data inconsistency and the limitation of current building energy and solar potential modeling methods in accounting for the urban context influences. This study tries to fill this gap by developing a GIS-based energy balance modeling system for urban solar buildings. This modeling system extends the system boundary from a single building to the urban building system, uses urban-scale data instead of costly survey, adopts widely used GIS-platform, and makes reasonable trade-offs between speed and accuracy. It consists of four major models: the Data Integration model, Urban Building Energy model, Urban Roof Solar Energy model and Energy Balance model. This modeling system is applied to Manhattan as a case study. The results show the spatial and temporal variations of building energy uses, the solar power potentials in the usable roof areas, and the self-supply and surplus ratio of buildings in Manhattan in 2012

Modeling Algae Powered Neighborhood Through GIS and BIM Integration

This paper aims to propose a modeling method for algae powered neighborhoods through GIS-BIM integration. In the first part of the paper, the applicability of different types of algae systems in an urban neighborhood are studied. The various systems of algae provide different strengths and weakness that affect their performance and suitability for given urban scenarios. Through extensive literature review, the variables that affect the performance of the micro-algae in the built environment are identified, with a focus on flat-panel photo bio-reactors and tubular photobioreactors. A previous GIS model for data management, performance analysis and design of the algae systems is reviewed [1], which shows its limitations in managing fine-grained structures and functions of algae systems. A bottom-up BIM approach to deal with these limitations is further explored. The algae-embedded built environment can be modeled in the parametric 3D BIM and Rhinoceros with a set of building parameters for the roof, façade, window to wall ratio, etc. Subsequently, solar exposure on building surfaces, the use of the buildings and their respective façade types would be studied. Parametric 3D models of the buildings allows for faster design modification and the creation of multiple design options. These models can be used to perform energy analysis using the parametric energy analysis tool to check for building energy use intensity (EUI). The bottom-up approach explored in this research design aims to facilitate visualization and analysis of the built environment and gauge the productivity of microalgae. Finally, a platform for BIM –GIS integration and its possibility is explored in this paper. © 2017 The Authors

Spatial Optimization of Residential Urban District - Energy and Water Perspectives

AbstractMany cities around the world have reached a critical situation when it comes to energy and water supply, threatening the urban sustainable development. The aim of this paper is to develop a spatial optimization model for the planning of residential urban districts with special consideration of renewables and water harvesting integration. In particular, the paper analyses the optimal configuration of built environment area, PV area, wind turbines number and relative occupation area, battery and water harvester storage capacities, as a function of electricity and water prices. The optimization model is multi-objective which uses a genetic algorithm to minimize the system life cycle costs, and maximize renewables and water harvesting reliability.The developed model can be used for spatial optimization design of new urban districts. It can also be employed for analyzing the performances of existing urban districts under an energy-water-economic viewpoint.Assuming a built environment area equal to 75% of the total available area, the results show that the reliability of the renewables and water harvesting system cannot exceed the 6475 and 2500 hours/year, respectively. The life cycle costs of integrating renewables and water harvesting into residential districts are mainly sensitive to the battery system specific costs since most of the highest renewables reliabilities are guaranteed through the energy storage system

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Relationships between building characteristics, urban form and building energy use in different local climate zone contexts: An empirical study in Seoul

© 2022 Elsevier B.V.The influence of building context on the relationship between building and its energy use has been attracting attention. However, most studies simply defined building contextual areas as within an arbitrary distance and measured their form with commonly used planning and design indicators. Such an approach often suffers from the lack of justifications on the context area size, confounding effects between indicators, and weak connection between those indicators and urban energy policy. This study uses the local climate zone (LCZ) as buildings’ thermal context area, and investigates the relationship between building characteristics, urban form, and residential building energy use in different LCZ contexts in Seoul, South Korea. A linear mixed model is employed to examine this relationship. Results show that LCZs as different contextual forms not only significantly influence building energy, but also impact the effects of building characteristics on building energy use. The results are further compared to another model with zoning classes, a widely used development control tool in planning, as contextual areas, and find the latter has much smaller influences. The findings suggest a promising application of the LCZ framework in understanding the form-energy relationship in complex urban environments and in energy-oriented urban planning.N

Identifying urban form typology of residential areas in major cities in South Korea using clustering

In South Korea, cities have experienced rapid development, resulting in diverse urban form patterns. While the typology approach has emerged for identifying different patterns for better understanding of urban development, typology studies are still lacking for Korean cities. This study identifies and compares urban form typologies for residential blocks in major Korean cities using clustering. Two cities are analysed which represent distinct regional city characteristics and planning themes in Korea: Seoul and Jeju. In each city, physical form data are collected in the Geographic Information Systems (GIS) format for calculating and analysing residential blocks. Urban form variables and principal components were analysed and used for K-means clustering. The results of clusters are then interpreted as urban form typologies. The identified urban form typologies in the two cities show the similarities and differences of typologies between the cities providing insights in the influences of regional characteristics, such as natural environment, culture, and of the planning patterns on urban form development patterns. The findings provide a better understanding of diverse urban forms in the three cities and their different local identities. The typologies can be utilized as references for urban and policy makers for sustainable planning and design

Surrogate Modeling Strategy for Urban Building Energy Simulation in Early-Stage Urban Design: A Case Study of Energy-Efficient Neighborhood Design in Seoul

This study focuses on developing an efficient surrogate modelling strategy for early-stage urban design, aiding in energy-efficient residential neighborhood design in Seoul. The methodology involves devising a design schema with important design parameters, generating 1,000 random designs via Latin Hypercube Sampling, and simulating each design’s energy use considering microclimate and shadow effects. Polynomial regression is used to develop surrogate models based on those energy simulation results, which is further validated with energy use measurements of real neighborhoods in Seoul. The developed surrogate model can provide quick evaluation of energy use with a moderate level of accuracy for early-stage energy efficient neighborhood design

A Geodesign Method of Human-Energy-Water Interactive Systems for Urban Infrastructure Design: 10KM2 Near-Zero District Project in Shanghai

The grand challenges of climate change demand a new paradigm of urban design that takes the performance of urban systems into account, such as energy and water efficiency. Traditional urban design methods focus on the form-making process and lack performance dimensions. Geodesign is an emerging approach that emphasizes the links between systems thinking, digital technology, and geographic context. This paper presents the research results of the first phase of a larger research collaboration and proposes an extended geodesign method for a district-scale urban design to integrate systems of renewable energy production, energy consumption, and storm water management, as well as a measurement of human experiences in cities. The method incorporates geographic information system (GIS), parametric modeling techniques, and multidisciplinary design optimization (MDO) tools that enable collaborative design decision-making. The method is tested and refined in a test case with the objective of designing a near-zero-energy urban district. Our final method has three characteristics. ① Integrated geodesign and parametric design: It uses a parametric design approach to generate focal-scale district prototypes by means of a custom procedural algorithm, and applies geodesign to evaluate the performances of design proposals. ② A focus on design flow: It elaborates how to define problems, what information is selected, and what criteria are used in making design decisions. ③ Multi-objective optimization: The test case produces indicators from performance modeling and derives principles through a multi-objective computational experiment to inform how the design can be improved. This paper concludes with issues and next steps in modeling urban design and infrastructure systems based on MDO tools. Keywords: Geodesign, Urban design, Urban infrastructure, Energy performance, Iterative process, Multi-objective optimizatio