Conference Program
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Last updated: Saturday, March 9, 2013
Paper Abstracts
Simulating Nonlinear Nano-to-micro Scaled Material Properties and Effects at the Architectural Scale
Simin Wang, Andrew Lucia and Jenny Sabin
The problem of simulating atypical and nonlinear nano-to-micro scaled material properties at the architectural scale is untenable given the complexity of calculating such data using current rendering and simulation platforms. Though existing rendering engines enable the simulation of material optical properties such as angle dependence, transparency, translucency, and color, the unique behavior and scale of many nonlinear nano materials' angular dependence and wavelength filtering properties requires the development of new tooling methods and workflows. eSkin-a project to develop passively responsive building façade systems, frames the larger foundation for this paper, which is narrowly focused upon our catalogue of tools where desired optical properties of nano & micro array structures are first simulated in order to extract angle and wavelength dependent quantitative optical data. Once calculated, these optical properties are then redeployed at the architectural scale utilizing custom written software platforms and algorithms.
The Faraday Pavilion: Activating Bending in the Design and Analysis of an Elastic Gridshell
Paul Nicholas, Elisa Lafuente Hernandez and Christoph Gengnagel
This paper reports the architectural and engineering design, and construction, of The Faraday Pavilion, a GFRP elastic gridshell with an irregular grid topology. Gridshell structures are self-formed through an erection process in which they are elastically deformed, and the prediction and steering of this aspect becomes a central part of both architectural and engineering design processes. While there are existing architectural approaches to determining the geometry of other kinds of form-active structure, as well as new engineering approaches to the simulation of bending active structures, a fast and light-weight design approach to bending active structures is not currently developed. In this paper, we introduce an approach to the architectural design of a bending active structure whereby the shell form and grid topology are determined by simulation. Particular features are that the grid topology is not pre-described, but rather emerges as part of the simulation, and that different calculative models relating to the material, element and structural scales are solved and synthesized by extending the technique of dynamic relaxation. Secondly, the results of this design modelling are provided as the input for a quantitative engineering simulation, where the equilibrium shape and load-bearing capacity of the elastically-bent structure is calculated with a non-linear, three-dimensional finite element model within the FEM-package Sofistik. We compare the advantages and disadvantages of both methods, which while complementary have important differences relating to the interaction with the design of the structure, differences in the definition of supports, connections and elements, the speed of calculation and the magnitude and precision of the results.
Self-Learning Algorithm as a Tool to Perform Adaptive Behaviour in Unpredictable Changing Environments - A Case Study
Elite Sher, Angelos Chronis and Ruairi Glynn
Adaptive architecture is expected to improve buildings' performance and create more efficient building systems. One of the major research areas under this scope is the adaptive behaviour of structural elements according to load distribution. In order to achieve this, current studies develop structures that adapt either by following a database of pre-calculated solutions, or by using massive computation resources for real-time calculations. This study aims to achieve an adaptive behaviour in real time, affected by load distribution, by implementing learning abilities on a case-study. This is done by applying a learning algorithm - Artificial Neural Network (ANN) on a physical prototype. The ANN was trained by an optimised database of finite solutions, which was created by a Genetic Algorithm (GA). Through this method, complex calculations are conducted 'off-line' and the component operates in a 'decision-making' mode in real-time, adapting to a versatile environment while using minimal computational resources. Results show that the case study successfully exhibit self-learning, and acquired the ability to adapt to unpredictable changing forces. This method can be applied over different structural elements (façade elements, canopies, and structural components etc.) to achieve adaptation to other parameters with an unpredictable pattern such as human behaviour or weather conditions.
Choreographic Architecture: Inscribing instructions in an auxetic based material system
Theodoros Themistocleous
This paper presents the development of an SLS 3D-printed auxetic structure actuated to a predefined form by an embedded pneumatic network through an iterative process of feedback between digital simulation and physical testing. This feedback process is critical to the development of a more accurate predictive model and to compose the geometry of the suggested structure. An approach based on the emergence of final structure from the convergence of the behavior of sub-structures has been introduced from the beginning and a methodology based on the analysis and synthesis of the simplest sub-system is the core of this research. The results indicate a promising simulation environment and a novel methodology for the design and fabrication of auxetic structures with embedded pneumatic actuation. This exploratory research suggests a fertile research space within the field of adaptive architecture and kinetic design.
Façade's Apertures Optimization. Integrating Cross Ventilation Performance Analysis In Fluid Dynamics Simulation
Chrysanthi (Sandy) Karagkouni, Ava Fatah gen Schieck, Martha Tsigkari and Angelos Chronis
Performance-oriented design has as a primary aim to in-troduce spaces that achieve acceptable levels of human comfort. Wind-induced airflow plays a significant role in the improving occupants' comfort in a building. This paper explores the extent to which simulation of natural airflow can potentially be a contributing parameter in the concep-tion of performance-aware designs. Testing the natural ventilation performance of a pavil-ion, the study employs Fast Fluid Dynamics simulation. A performance analysis is conducted, whereby an array of automated feedback loops carried out by a genetic algorithm can produce a number of acceptable solutions as regards the optimization of facades' openings. The experimentation conducted proves the ability of the model to yield design instances that fulfill a number of environmental criteria related to airflow and human comfort. In this light, the paper suggests that the aforementioned method can be used as an experimentation platform to influence the direction a designer may take when considering a design proposal.
A Review Of The Brazilian NBR 15575 Standard: Applying The Simulation And Simplified Methods For Evaluating A Social House Thermal Performance
Tassia Helena Teixeira Marques and Karin Maria Soares Chvatal
The new Brazilian ABNT NBR 15575 Standard recommends two methods for analyzing housing thermal performance: a simplified and a computational simulation method. The aim of this paper is to evaluate both methods and the coherence between each other. For this, the thermal performance of a low-cost single-family house was evaluated through the application of the procedures prescribed by the Standard. To accomplish this study, the EnergyPlus software was selected. Comparative analyses of the house with varying envelope U-values and solar absorptance of external walls were performed in order to evaluate the influence of these parameters on the results. The results have shown limitations in the current Standard computational simulation method, due to different aspects: weather files, lack of consideration of passive strategies, and inconsistency with the simplified method. Therefore, this research indicates that there are some aspects to be improved in this Standard, so it could better represent the real thermal performance of social housing in Brazil.
Thermal Reconstruction of a Crime Scene Using Calibrated Simulation
Nathan Brown, Susan Ubbelohde, George Loisos, Santosh Philip and Ibone Santiago
This study utilized energy simulation in support of a forensic pathology time of death analysis for a corpse discovered in a single family residence two years prior to the study. In order to produce an accurate estimate of the interior temperature profile at the time of death, a thermal model was constructed using EnergyPlus and calibrated using environmental monitoring data from the site. The thermal model was able to predict the temperature in the room of interest within 1.4°C (2.5°F) with 90% confidence. This model was then altered to account for known differences between the monitoring period and the period of interest, and used to predict what the temperature profile had been at the time of death. This study adds to a small body of work that compares simulated to measured performance data for unconditioned spaces, which should have a growing relevance as building energy performance simulation (BEPS) tools are used to model passive strategies.
Modeling, Analysis and Simulation of a Form-Found Civic Sculpture for Lower Manhattan
Zak Kostura, Erin Morrow and Ben Urick
Analysis and design of an 8-storey cable net sculpture for a new transit center in Lower Manhattan required its designers to adopt a highly integrated computational approach. This approach combined aspects of structural analysis, form-finding, 3D and parametric modeling to achieve the artistic objectives of the sculptural form while ensuring desired performance of the extensive tensile system. This paper presents an overview of the artistic and functional objectives of the cable net and describes in detail the design approach of the project team, including software integration, nonlinear analysis, geometric modeling, documentation and construction administration. It outlines a partial approach toward performance-based design for a system with strong aesthetic objectives and a collaborative approach to construction administration to manage risk amogst the various stakeholders.
Visualization in 3ds Max for Cell-DEVS models based on Building Information Modeling
Victor Freire, Sixuan Wang and Gabriel Wainer
Building Information Modeling (BIM) increasingly ben-efits from modeling, simulation and visualization tech-niques. 3D visualization can provide a better way to obtain visual simulation results in BIM authoring tools. In this pa-per, we focus on improving interoperability, traceability, re-usability and visibility of 3D visualization. We employ the DEVS (Discrete Event Systems Specification) formalism and its cellular extension Cell-DEVS, providing a method for visualizing Cell-DEVS models based on moving entities. We used this technique to develop a 3ds Max visualization plug-in for Cell-DEVS models based on BIM. This tool can show different animation models and allows designers to fil-ter the building for visibility. We also show two case studies applying this tool for evacuation and occupancy simulation.
Evaluating the Performance Robustness of Fixed and Movable Shading Devices Against Diverse Occupant Behaviours
William O'Brien
Given the diverse operating conditions, weather conditions, space users, and occupant preferences of buildings, it is commonplace to provide occupants with multiple means to adapt their immediate indoor environment. However, numerous studies have shown that occupants sub-optimally use such controls to improve comfort during times of significant discomfort, but are much more passive when the source of discomfort is alleviated. Occupant-related building performance simulation (BPS) models continue to use very simple and rigid rules when a building's performance is predicted, despite the topic's complexity. This is likely an artifact of envelope load-dominated buildings, whose energy use is mostly dependent on their ability to isolate the indoor environment. But as envelopes and HVAC become more efficient, occupants are playing an increasingly important role on building performance; especially for highly efficient building (e.g., net-zero energy buildings). Traditionally the associated uncertainty of these effects has been excused for the designer and isolated during design by focusing on energy performance relative to a reference building. This paper proposes a method using a combination of probabilistic occupant models and explicit models of adaptive comfort to gain an improved understanding of robust building design. Results of an example of yield 45% lighting energy savings if a fixed shading device is present.
Simulating the Sensing of Building Occupancy
Simon Breslav, Rhys Goldstein, Ben Doherty, Dan Rumery and Azam Khan
Accurate building occupancy information can be beneficial in minimizing energy use by improving the intelligence of a Building Automation System (BAS) and helping designers predict the effect of different design options on occupant behavior. However, current occupancy measurements are quite inaccurate due to limitations in sensing technology and the resulting discrepancies between sensor data and what actually happens. In this paper we explore the use of simulation to model occupant behavior in combination with motion sensors to be able to study the relationship between known and measured occupant behavior. An extensible occupancy model, influenced by computational cognitive science and implemented using established modeling conventions is presented along with a simple experiment comparing the effects of different sensor density levels.
Development of Discrete Event System Specification (DEVS) Building Performance Models for Building Energy Design
H. Burak Gunay, William O'Brien, Rhys Goldstein, Simon Breslav and Azam Khan
The discrete event system specification (DEVS) is a formalism for describing simulation models in a modular fashion. In this study, it is exploited by forming submodels that allow different professions involved in the building design process to work independently to create an integrated model. These submodels are the building, the HVAC system, and the occupant. In this study, a coupled DEVS building energy model of a generic office space is presented to demonstrate the viability of the DEVS formalism for BPS based design. Results indicate that the DEVS formalism is a promising way to improve poor interoperability between models of different domains involved in building performance simulations.
City Information Modeling (CIM) and Urbanism: Blocks, connections, Territories, People and Situations
Todor Stojanovski
The urban theory is voluminous body of knowledge. There is a kaleidoscope of urban definitions and standpoints, but there are no tools that capture the variegated viewpoints and representations in urbanism. In this article I look at different urban theories, discourses and representations in architecture, sociology, geography, economy, transportation, computer science in order to conceptualize city information modeling (CIM). CIM is conceived and discussed as a system of blocks with dynamic relations or connections that define and redefine territories. The urban life today is a sequence of temporally inhabited and interconnected spaces, movable or fixed. The connections between spaces inspire or inhibit contacts and interactions between people. They bend times and continuously shape and reshape spaces, sociabilities and situations. In architecture there was an evolution from computer-aided design (CAD) to building information modeling (BIM), but in urbanism, where the geographic information systems (GIS) dominate, there is no such analogy.
A Study of the Relationship between Urban Form and Environmental Performance for Three Urban Block Typologies of Paris
Ji Zhang
This study explores the relationship between urban form and environmental performance by analyzing three representative urban street block typologies proposed for Paris through her urban history. The performances of these typologies in terms of daylight potential, annual insolation, exposure to the sky, and potential to produce urban heat islands were simulated and compared. The implications of the results in 1) the importance of appropriate performance indicators to be used in comparative studies, and 2) the relationship between urban form, density, and environmental performance were discussed.
End-node Approach for Pedestrian Flow Simulation
Hiroshi Ota
Studies on urban networks mostly focus on street systems, such as streets as links and junctions as nodes. This paper proposes the evaluation model with "building-nodes", to examine how buildings may contribute to the whole urban network. Firstly, by evaluating the total floor area of building nodes in the calculation process of betweenness centrality, the paper proposes the "potential pedestrian flow" which has acceptable correlation coefficient with the pedestrian flow in the actual street network. Secondly, the paper explores the approach to regard urban network as a queueing network where "end-node congestion controls" are possible. For the general understanding of the methodology, the simulation in this paper principally focuses on the effect of changes in building clusters, which elements are all defined as end-nodes, and the advantage of the change in decentralized clusters was confirmed.
Designing-In Performance: Cloud based Simulation and Multidisciplinary Design Solution Space Search
Shih-Hsin (Eve) Lin and David Gerber
This research is built upon a previously established multidisciplinary design optimization (MDO) framework and further explores the impact of this framework on the early stages of design. Specifically, this paper addresses the potential of introducing a cloud-based approach to tackle geometrically complex design problems and to facilitate early stage design exploration. To address these interests two experiment sets are presented and then discussed in the context of the application of cloud-based computing. First, is a hypothetical scenario possessing complex geometry to understand how the existing established framework assists in the exploration of complex geometric design problems. Second, is a pedagogical benchmark case allowing for the observation of the human versus automated decision making process. By comparing these processes the impact of the established MDO approach on "designing-in performance" and the potential impact of applying cloud-based computing to the MDO framework can be revealed and discussed.
From Statistical to Diagrammatic Geo-Spatial & Time Based Data Visualization Through Parametric Modeling
Ming Tang, Chris Auffery and Mingming Lu
The paper describes experiential learning outcomes in the application of geospatial data to generate diagrammatic representations. It also focuses on models and animations used in engineering, architecture and urban planning to visualize specific urban issues such as urban health, education, crime, and air pollution, as they are currently being confronted in major cities such as Cincinnati. The paper discusses how to reconstruct geospatial and time-based data into various representations. It describes the process of visualizing and representing databases with emerging parametric modeling and animation tools. Starting with statistical data, parametric design tools are used to decode and recode the social, cultural, economic and environmental complexity within the parametric equation. Computational tools for architects and urban designers such as Geographic Information Systems (GIS), Excel, Maya, Rhino and Grasshopper plugin are used to build platforms that allow parametric control of the rendered outcome.
Integrated Design in the Simulation Process
Martha Tsigkari, Angelos Chronis, Sam Conrad Joyce, Adam Davis, Shuai Feng and Francis Aish
During the past decade the construction industry has been witnessing a constant shift in the way it operates. The advances of technology have made possible the adaptation of a more direct, performance-driven design approach based on multi-objective -- and sometimes contradicting -- criteria of environmental, structural, economic and aesthetic impact. As a consequence, the various teams of consultants involved in the process no longer inform it consecutively, forcing various changes at different stages of the design. Instead, building projects increasingly comprise numerous design issues that can be delegated to small groupings of architects, engineers, and consultants to be resolved simultaneously, in parallel. In the light of this new status quo, the significance of new customized simulation tools and interfaces, capable of providing near real-time feedback and driven by multiple input criteria, looms as a potential game changer to the industry. This paper outlines the advances implemented by the authors to support these new integrated workflows.
Building Simulation Weather Forecast Files for Model-Based Predictive Control
José A. Candanedo, Éric Paradis and Meli Stylianou
Model-Based Predictive Control (MPC) has received significant attention in recent years as a tool for load management in buildings. MPC is based on predicting the response of a system based on knowledge of future inputs, such as weather and occupancy. Despite the availability of online weather forecasts, there is a lack of software tools enabling the use of weather forecast information in building modelling. This paper describes a "proof of concept" approach to the creation of EnergyPlus Weather (EPW) files containing weather forecast information. These EPW files, updated at periodic intervals, also contain up to date recorded measurements, thus permitting to establish initial conditions by applying "warm up" simulations. The combination of recorded data and expected weather allows the use of these files in predictive control. This approach can be readily reproduced for different weather file formats and other locations.
How Hot Can the University Campus Get in 2050? Environmental Simulation of Climate Change Scenarios at an Urban Neighbourhood Scale
Chengzhi Peng and Amr Elwan
Based on the results from simulating a case study neighborhood design to be built in New Cairo, Egypt, a conceptual framework and an environmental simulation work-flow towards Climate Change Conscious Urban Neighborhood Design (C3UND) is proposed. Coupling neighborhood outdoor and building indoor simulations, the C3UND work-flow is further applied to a neighborhood site at the Sheffield University campus in England with weather data representing 2010s and 2050s. We describe how the ENVI-met platform can be applied to contextualize Ecotect building simulations, taking into account the present day as well as future simulated urban micro-climatic conditions. This study suggests that environmental simulation of climate change scenarios at an urban neighborhood scale is currently achievable but not without considerable gaps. The lessons learned and areas for further research are discussed.
Improving Building Performance at Urban Scale with a Framework for Real-time Data Sharing
Xiufeng Pang, Tianzhen Hong and Mary Ann Piette
This paper describes work in progress toward an urban-scale system aiming to reduce energy use in neighboring buildings by providing three components: a database for accessing past and present weather data from high quality weather stations; a network for communicating energy-saving strategies between building owners; and a set of modeling tools for real-time building energy simulation.
Isomorphic City: A Customizable Future Scenario
Susannah Dickinson, David Gonzalez and Kyle Szostek
This paper discusses a future city design and research project for Tucson, Arizona, USA. The project, Isomorphic City, set in the year 2087 develops a truly customizable and ever-adapting computational approach to the existing built environment. Part of the challenge was to design digital methodologies that could simulate this scenario in as live a way as possible, incorporating real-time, live data into the equation, ranging from environmental criteria to social media information. Form was the result of inputted parameters verses the making of form in a traditional object-like fashion. The project anticipates a shift of simulating the urban condition with a rule based set of criteria to a more human agent-based approach based on collective intelligence and social behaviour patterns.
A Collaborative Multi-touch, Multi-Display, Urban Futures Tool
Michael van der Laan, Ronald Kellett, Cynthia Girling, Maged Senbel and Tao Su
Recent technological advances in multi-touch, multi-display computing interfaces and networking software have enabled the integration of all three roles into a single collaborative work space. This paper describes the development of one such application focused at carrying out complex urban design exercises through simple, transparent, and interactive means. Constructed through a federated system architecture, the system connects three independent applications: Google Earth, a Building Information Model (BIM) database, and an Indicators Dashboard (ID). The goal of this work is to provide a diverse group of stakeholders with a better understanding of the environmental impact and tradeoffs associated with a range in potential urban futures.
Solutions for Scalability in Building Information Modeling and Simulation-Based Design
Sixuan Wang, Gabriel Wainer, Rhys Goldstein and Azam Khan
Simulation-based design can enable a number of advanced architectural and engineering applications such as energy modeling, occupant behavior prediction, or structural integrity analysis. To help make simulation-based design practical, scalability in terms of data and computation is needed. By using a Model-Driven Architecture (MDA) approach together with the RISE (RESTful Interoperability Simulation Environment) web interface, a generic scalable simulation design framework is presented. In our system, Building Information Modeling (BIM) data is represented in the Industry Foundation Classes (IFC) open standard from which Domain Specific Models (DSM) may be extracted for particular applications. The open RISE interface to a DEVS (Discrete Event System Specification) simulation provides computational scalability. We present a case study in which our system is applied to an evacuation model of a multi-floor building. We also show a 3D visualization of the simulation results to support further decision making. By enabling designers to extract information automatically from IFC and run simulations remotely, this kind of scalable system makes simulation a viable part of the design process.
Evaluation of Indoor Climate in Low Energy Houses
Liesbeth Staepels, Griet Verbeeck, Staf Roels, Liesje Van Gelder and Geert Bauwens
The aim of the EU EPBD is to realize lower energy consumption in buildings, without neglecting the indoor climate, which can be specified as thermal comfort and indoor air quality. The research analysed 70 recently built dwellings in Flanders, Belgium, ranging from standard execution over low energy up to even energy positive houses. A monitoring campaign was set up to evaluate the indoor environment quality, both during winter and summer period. Both in winter and summer, the temperature is mostly within comfort boundaries. However, in better insulated dwellings the mean temperature is generally somewhat higher and the deviation is smaller whereas on warm days the temperature can rise uncomfortably in both living room and bedroom. CO2 and humidity measurements show good to reasonably good indoor air quality, independently from the type of ventilation system.
HubPod: Integrating Acoustic Simulation In Architectural Design Workflows
Brady Peters, Jane Burry, Nicholas Williams, and Daniel Davis
This paper reports on research that seeks to integrate acoustic simulation into an architectural design workflow. The goal of this research is to develop rapid and accessible workflows for architects that allow them not only to tune the acoustic performance of designs at the scale of the room, but also at the level of the geometry and materiality of the surface. The project that serves as the test case is the HubPod, a semi-enclosed meeting room situated within an open working environment. As this study builds on previous research which investigates the acoustic properties of hyperboloid surface geometry, the main drivers for design were both the acoustic performance as well as the complex geometric and fabrication constraints involved with setting out and constructing the hyperboloid geometry. This paper focusses specifically on the integration of the acoustic simulation. Four design workflows were developed: two of these allowed for the investigation the acoustic performance of the room using acoustic simulation software; the other two allowed for the measurement and visualisation of the acoustic performance the surface using custom-written scripts to calculate and visualise sound scattering. This paper will present some of the data produced by these simulations, and reflect on the value of the different workflows and simulation methods to this architecture project.
Data Mining Using ANN for Finding the Effects of Building Structure on Thermal Comfort Parameters
Lubaid Ahmed and Abdolreza Abhari
The main objective of this work is to use artificial neural network for data mining in the thermal comfort data of a building environment datasets collected by wireless sensor network. Currently there are many research activities trying to use data mining methods to find data patterns in the machine generated data (i.e., big data). The data collected in this work are composed of temperature, humidity and air flow values of 4th floor of the educational building. The main goal of this research is to find the effects of building structure design on the collected parameters. This will help to answer the questions regarding to change the structure design and examine the effects on thermal comfort parameters in a building.
A Generalised Event Driven Framework For Building Occupancy
Gandherva Gunathilak, Aiswarya Prasannakumar, Negin Nazarian and Homa Naeimi
Building occupancy is very important for building energy simulation and research, however generating an occupancy model that is closer to the real world occupancy patterns is a very challenging task. In this paper, we have proposed a generalized event driven framework for the simulation of building occupancy. Real humans work together in groups and their presence is affected by events. So, the proposed model incorporates the concept of events and groups. Unlike the existing building occupancy models which were based on Markov chain, the proposed framework is fully event driven and group based which makes it closer to reality. The proposed model develops a generalized framework which will be able to simulate the occupancy patterns for any building be it an office, lab or even a house.
Simulation for Planning Passenger and Freight Transportation System Projects
Beth Kulick
Transportation projects, such as those for maritime ports, airports, passenger rail and freight rail are typically large investments and they can be a complex system that includes multiple modes, new technologies, operating concepts, and operators. These projects are initiated by metropolitan planning organizations, city port authorities, and statewide department of transportation agencies and others. Architectural or engineering services firms are often contracted to assist with the project planning steps. The planning processes include evaluating and ranking alternatives with subjective and quantitative criteria. Additionally, as projects evolve, there is a need to gain stakeholder approval and conduct environmental impact reviews. Simulation modeling provides a unique and flexible framework to assist with concept development, stakeholder consensus building, and public approval during environmental impact reviews. Modeling provides the ability to quantify concept performance differences between alternatives and demonstrate that a concept provides operational sustainability for each of the stakeholders and modal flows. This paper describes several transportation planning projects and how simulation modeling can provide quantitative performance metrics to support the planning processes to enable the project to move towards advanced design and engineering stages.
Preliminary Results of Model Predictive Control of Shading Systems
Brent Huchuk, William O'Brien and Cynthia Cruickshank
Shades in buildings are widely installed and are an effective technique for managing solar gains and occupant comfort. A model of a typical office space located in Ottawa, Ontario has been created and the model was developed for analysis under variable conditions. Analysis has resulted in the generation of an advanced reactive system facilitated by the use of the energy management system (EMS) built within EnergyPlus along with a predictive control system optimized for the minimizing of the energy demand by the office space. The approach to optimization is done through the use of a basic model predictive control facilitated by the use of MATLAB (Mathworks 2011) and EnergyPlus (DOE 2012). The predictive system at this stage is delivering reductions of 5% during shoulder season over its reactive counterpart but this work is still on-going.