Testing and application of the computer model ‘SIMULEX’

A number of computer models for the evacuation of buildings have been produced in recent years. These models typically use a system known as ‘network-node’ modelling, which makes a number of large assumptions concerning human motion. Methods used in the software package ‘SIMULEX’ differ from the traditional methods of assessing motion in terms of average parameters and ‘flow rates’. The most significant feature of the model is the geometrically accurate simulation of the evacuation movement of each individual person from a building space. The algorithms which achieve this movement are not based on any standard method of evacuation modelling, so it is important to assess how realistic the algorithms prove to be, and also to investigate the performance of the system as a whole.This paper describes a series of tests in which SIMULEX models the movement of a large group of people through a number of exits of different widths. The maximum sustainable flow rates that were achieved in the tests are presented and compared to data from different sources. The application of SIMULEX to the proposed design of a large commercial store is also discussed.     

Examples of Groundwater Modelling in Environmental Assessment Studies

The development of groundwater modelling techniques is reviewed, from analogue and early digital models to current commercial software packages. The parallel development of the application of groundwater modelling as a tool for evaluating the impact of developments and structures on hydrogeological systems is also examined. Formerly, new model programs were written for each application, requiring that the user had programming skills as well as hydrogeological expertise, and model development periods were measured in months or years. Now, a knowledge of the program details is not necessarily a prerequisite for a satisfactory model, which may be designed, constructed, calibrated and used in days or weeks. However, a thorough understanding of the conceptual model underlying a software package, and of the numerical methods used to generate the output, is as important as ever. Examples are given in the paper of the exploitation of commercial packages to produce rapid assessments of the impact on groundwater of proposed mineral workings and similar developments.     

Effect of 2D modelling of thermal bridges on the energy performance of buildings: Numerical application on the Matisse apartment

This paper describes the modelling approach used to accurately evaluate the effect of thermal bridges on the energy performance of buildings. The heat transfers in the intersections of walls were initially modelled in Sisley software. These models were then reduced and integrated in Clim 2000. The simulation results were compared against the models obtained from thermal regulation values. For standard wall configurations, it was seen that the detailed modelling of heat transfers provides an additional accuracy of about 5% in terms of the evaluation of the building’s heat losses.     

Nitrification Trials at Dunnswood Sewage-Treatment Works and Process Modelling Using WRc STOAT

The paper describes an experimental programme on an existing full-scale plant to demonstrate the conditions which are necessary to achieve nitrification. The programme was guided by parallel computer modelling of the plant using the WRc STOAT simulation package. Nitrification was successfully achieved, and the studies and computer modelling indicated how the plant should be extended to provide year-round nitrification. The effect of storm flows on effluent quality was assessed for each process option. The effluent quality consent of 5 mg/l ammoniacal nitrogen as a 95 percentile was achieved, and there was a significant improvement in river water quality with respect to ammoniacal nitrogen.     

Retail impact analysis with loosely coupled GIS and a spreadsheet

This paper describes an innovative computer‐based system, GIS‐SHOP, for providing low‐cost decision support for retail impact analysis. The system implements a loosely coupled approach to urban modelling using a widely available, low‐cost desktop geographic information system (GIS) and an electronic spreadsheet to develop a gravity‐model‐based retail shopping model. The paper begins by reviewing the power—and limitations—of the current generation of GIS for planning and the need to extend this technology to develop more powerful planning support systems (PSS). It then describes the GIS‐SHOP model which uses ESRI's ArcView® 2.1 and Microsoft's Excel^® 5.0 together to provide analytic and display capabilities which are available in neither package alone. The paper concludes by considering the advantages and disadvantages of this loosely coupled modelling strategy.     

Modelling of heated composite floor slabs with reference to the Cardington experiments

This paper describes a method of modelling composite floor slabs in fire conditions using a stress-resultant approach. The FEAST suite, which consists of two main computer programs is described. The first, SRAS, is designed to model the behaviour of arbitrary orthotropic plate sections at elevated temperatures. The second program, FEAI, interfaces with the finite element package ABAQUS, allowing realistic models of the behaviour of whole structures in fire conditions to be obtained. The paper describes how SRAS was used to analyse the floor slab of the Cardington fire tests and results showing the behaviour of the slab under a variety of loading conditions are presented. The suitability of FEAI as a key component in the analysis of redundant structures under fire conditions is briefly demonstrated.     

Evolution and validation of a thermal probe model

This article describes the progress on the modelling of a thermal probe apparatus for in situ measurement of the thermal properties of construction materials, using the commercial heat transfer simulation program Voltra. The article describes the evolution from a model representing a theoretical line source to a model representing a two-dimensional elementary thermal probe. The new model uses a more dense spatial grid. The results of simulations modelling a solid stainless steel probe, and a stainless steel shell filled with glass inserted into stabilized water (agar), glycerine with fibre, toothpaste and polytetrafluoroethylene (PTFE) are described. These models are validated using data obtained through recent laboratory studies; continuity with the earlier work is demonstrated. Comparison of simulation results with experimental data confirms that percentage errors for conductivity and diffusivity are lowest for the model of the glass-filled probe.     

Visualization in environmental management: beyond the buzz word

Environmental management is a scientifically and procedurally complex task requiring the involvement of a range of disciplines. Increasingly this process is being rendered more tractable through the application of geographic information systems (GIS) technology. When such systems are effectively integrated with biophysical modelling software a spatial decision support system can be achieved. The outputs of such a system are often in the form of visualizations, i.e. a sequence of graphics (perhaps of unit length and possibly including text), designed to meet specific communication objectives. This paper describes general requirements for the design of visualizations.     

Energy efficiency and solar energy in European office buildings: a mid-career education initiative

This EC ALTENER programme project sought to develop an integrated package of teaching materials on solar energy and energy efficiency in office buildings. The ultimate audience is a multi-disciplinary one, including architects, building services engineers, building economists and building energy managers. The project focused on mid-career education and the primary audience targeted by the project consists of the organisers and instructors of mid-career courses for these four professions in the 15 EU member states. The paper describes the process undertaken by the four collaborating organisations, and the resulting educational material. The package includes eight technical modules, with four exemplar case studies, one of which covers the refurbishment of an existing building, and a training software program. Finally, the package also includes four instructor’s modules, one for each of the four target audiences.     

Principles and practical aspects of an automatic calibration procedure for urban rainfall-runoff models

Automatic methods for model calibration take advantage of the speed and power of computers, while being objective and relatively easy to implement. This paper presents the principles of automatic calibration applicable for urban rainfall-runoff modelling. The automatic scheme was developed by modifying the computer code of the MOUSE software package to include the shuffled complex evolution optimization algorithm with appropriate objective functions. The kinematic wave model was applied for the surface runoff computation. The output of the rainfall-runoff modelling was used to design a sedimentation basin. The practical aspects of applying automatic calibration results using different objectives are elaborated. It is clearly demonstrated that the proposed automatic scheme can be applied in urban water engineering design.     

An approach to the optimum thermal design of office buildings

The paper describes a method for determining a thermal design for an office building which minimizes the sum of initial costs and running costs discounted over the life of the building whilst satisfying constraints deriving from technological and comfort requirements.A thermal model of an office building is described in terms of heat supply and heat losses and some ingenious features of the modelling are presented. Costing techniques for heating and insulating the building are also described. An optimization algorithm based on geometric programming is then applied to the thermal model and typical results are presented. The importance of sensitivity analyses of the results is stressed.     

Web application for thermal comfort visualization and calculation according to ASHRAE Standard 55

Thermal comfort is one of the fundamental aspects of indoor environmental quality and it is strongly related to occupant satisfaction and energy use in buildings. This paper describes a new web application for thermal comfort visualization and calculation according to ASHRAE Standard 55-2013. Compared to existing software, the web application is free, cross-platform, and provides a visual and highly interactive accurate representation of the comfort zone. Its main features are: dynamic visualization of the comfort zone on psychrometric, temperature-relative humidity, and adaptive charts; new implementation of the Elevated Air Speed model; local thermal discomfort assessment; compliance document automation for LEED thermal comfort credits; metabolic activity and clothing insulation tables and dynamic models; and compliance with the standard. The tool can be used by architects, engineers, building operators, educators, and students.     

An Integrated ComDuter Model to Aid the Planning of Concrete Structures

Abstract: This paper describes the general architecture of a prototypical micro CAD-based integrated model being developed at Southborough University to aid the planning of in-situ concrete structures. The model is based on the coupling of two low cost and powerful project management (Artemis 2000) and computer aided design systems (AutoCAD 10) through an intermediary package (dBase IV). The main aim of this model is automate the planning process of in-situ concrete structures, particularly the generation of network plans, using data generated by CAD systems. The model functional specifications (i.e., modeling, drafting, quantities and materials scheduling, time analysis, cost analysis, and reporting) were established after a thorough review of current planning models, a detailed questionnaire survey conducted amongst the main UK and USA contractors on the current status of planning techniques and information technology applications, and a detailed study of the various problems facing CAD-based models. This model consists of three individual sub-systems: modelling, data transfer and planning. The integration of these individual sub-systems has been achieved on an IBM PS/2 MODEL 70. This enables the generation of network plans in the AutoCAD package (modelling subsystem) which are then automatically transferred (data transfer sub-system) to the Artemis system for time and cost analyses (planning sub-system). This paper outlines the work done so far and illustrates the proposed concept with a simplified case study.     

State Space Analysis of Dynamic Closed Loop Environmental Systems

Structured, generalised, digital modelling and simulation software tools that enable engineers to more easily produce formalised, documented and transferable software for prediction of thermal performance and energy use in buildings are described. The basis for these tools is modern state-space analysis techniques that cast modelling equations into a vector-matrix form ideally suited for digital computation. An automated building modelling capability generates detailed and simplified models directly from building plans through use of a library of construction element models (walls, floors, etc.). A user-oriented program interface enables interconnection of the building model with other component models selected from a library of HVAC equipment. controls, internal load schedules, and weather data to construct a closed-loop system simulation. Theoretical considerations for the modelling methodologies implemented in these tools are discussed, along with techniques to systematically reduce the modelling complexity and simulation costs without loss of accuracy. Plans to implement the simulation tools on a minicomputer with an array processor are overviewed.     

Dynamic thermal CFD simulation of a typical office by efficient transient solution methods

This paper describes the evolution and application of an efficient dynamic thermal modelling (DTM) procedure, developed within computational fluid dynamics (CFD). The results of a case study to simulate the dynamic thermal conditions within a typical office space using the novel DTM–CFD procedure are reported. The main area of investigation was the ability to account for the time-varying thermal response of building fabrics to internal and external ambient conditions and the consequential effect on the air inside the enclosure. The proposed DTM–CFD procedure utilised a transient time-varying grid schedule, ‘Freeze-Flow’ and ‘Boundary Freeze’ techniques. ‘Freeze Flow’ paused the solution of all governing equations of fluid flow, except temperature; while ‘Boundary Freeze’ froze temperatures at boundaries of the CFD model whilst solving all equations in the flow domain. The DTM–CFD procedure provides the potential for solving the problem of generating large quantities of data, whilst effectively and accurately modelling heat transfer through the building fabric and internal air simultaneously using CFD alone. An assessment of the performance of the DTM–CFD procedure was made through inter-model comparisons with fully transient CFD solutions. The procedure was successful in providing more detailed dynamic thermal simulations than would have otherwise been obtainable from a DTM and more efficiently (simulation time) than a CFD model.     

火灾中考虑整体性的钢梁破坏形态研究

1990年英国broadgate火灾之后,结构整体性以及由于温度而在整体结构中产生的附加应力得到了人们的重视。处于整体结构中的梁的破坏形态与单个构件的梁的破坏形态有较大差别,当考虑梁的悬链线效应时其抗火承载力明显提高。文章采用大型通用有限元程序ANSYS,对T.C.HLiu所做试验进行了验证,表明了有限元计算悬链线效应的可靠性,同时通过计算分析,提出了处于整体结构中钢梁在火灾中破坏的5个阶段,并给出了钢结构防火的概念设计建议。     

Development of an office tenant electricity use model and its application for right-sizing HVAC equipment

As a consequence of considerable uncertainty about occupancy, occupant behaviour, and the corresponding effect on thermal loads in buildings, it is difficult to correctly size heating, ventilation, and air-conditioning (HVAC) equipment. Mechanical engineers avoid liability of potential under-capacity and corresponding thermal discomfort by making conservative assumptions about occupants. Meanwhile, there has been a surge in research on characterizing occupants through increasingly advanced modelling approaches to support building performance simulation, but these have focused on agent-based models representing individual occupants, which may be impractical for building-level HVAC equipment sizing. This paper describes the development of a data-driven stochastic tenant model using 15 months of data from 17 independent commercial tenants. The model is implemented in EnergyPlus to examine its potential for an improved HVAC equipment-sizing procedure. The results show: the standard schedules are reasonable though conservative; oversizing equipment does not greatly improve comfort; and the tremendous importance of modelling inter-tenant diversity.     

A comparison of a FLOW3D based fire field model with experimental room fire data

This paper describes the application of a fire field model based on the FLOW3D CFD software to the simulation of fire induced flows in domestic sized rooms. Several scenarios are examined consisting of various sized fires, fire locations and door sizes. Comparisons are based on upper-layer room temperatures, mass fluxes in and out of the fire compartment and door-way vertical and horizontal temperature and velocity profiles. For most cases the model agrees reasonably well with the observed trends, however the results suggest that significant mesh refinement is required to produce results in quantitative agreement with experimental results. A close examination of the horizontal door-way velocity profiles highlights the need for careful modelling and experimental practices in this region.     

多排孔混凝土空心砌块热工参数计算方法研究

《民用建筑热工设计规范》仅给出单一材料的热工计算参数,对于多排孔混凝土空心砌块并没有给出可选的热工参数。文章采用复合材料划分孔道的办法计算多排孔混凝土砌块的平均导热系数和平均蓄热系数,为这类材料在节能设计中的应用提供必要的参数,利于多排孔混凝土空心砌块的推广。     

HV－STAR软件包的开发与应用

着重介绍了ＨＶ－ＳＴＡＲＣＡＤ软件包的开发与应用，指出了目前在暖通专业工程设计软件开发和应用过程中普遍存在的几个问题并提出了建议。