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The Definition Of Bim Information Technology Essay

The aim of the project is to do an energy analysis of a building using Building Information Modeling. Understanding BIM will be the first step in this project. It has to be well analysed and its uses and concepts have to be studied in detail. Various BIM compatible software packages such as Revit, SketchUp and also energy plus will be studied during the course of the project.

A 3D building model will be developed using existing graphical interface. Data model is to integrated to some existing energy analysis softwares to perform energy analysis.

“Building Information Modelling is digital representation of physical and functional characteristics of a facility creating a shared knowledge resource for information about it forming a reliable basis for decisions during its life cycle, from earliest conception to demolition.”[1]

 As defined by Autodesk is:

“The creation and use of coordinated, internally consistent,computable information about a building project in design and construction. This concept has changed the way industry professionals worldwide think about how technology can be applied to building design, construction, and management.”[2]

What is BIM? http://www.skyscraperpicture.com/dusseldorf03.JPG

The term ‘‘BIM’’ was framed by Autodesk in he year 2002 as an innovative new approach to design, construction and management. BIM means building information modelling. This is building design methodology by which various engineers working in a project can coordinate easily by working under a same platform and exchange information seamlessly.

Quest for BIM:

In a project, there are many communication gaps between the various engineers such as structural engineer, architect, construction engineers and owner. This is because each engineer works with their own software(structural engineer uses a design software while an architect uses an architectural software) so when changes are made in structural design it becomes difficult and time consuming for the architectural engineer also to implement the same change and also increases the chances of errors. So this demands for a methodology which has a common platform for all the engineering disciplines to work on and which will creates a link between all of them. So this methodology is called Building Information modelling. This concept is not new to the construction industry because the three dimensional capability of the BIM has been a dream for the construction industry.

BIM diagram

“Most design practice today, rests to the left of the first red line. In the CAD zone of the diagram the computer is used to automate the drawing board in that it works with lines and shapes and text blocks to produce traditional looking drawings which are conceptually no different from those of the drawing board. This is Phase zero. In the next phase, levels move into the third dimension and the potential for more sophisticated manipulation to help both the design and interpretation processes increase significantly. Within this phase the term 3D can be used for the creation of useful drawn views in three dimensions enabling functions such as services/structure clash detection to achieve some degree of reliable automation.

A BIM system can of course produce drawings but is no longer based on lines, shapes and text boxes but on data sets that describe Today CAD is no longer based on lines, shapes and text boxes but on data sets that describe objects virtually, as they will be physically handled by operatives, trades-people, specialists, and even machines and robots. The most pressing demand is true interoperability and the capability for proper integration allowing the inputs of the various professionals and specialist to come together”. [Mark Bew and Mervyn Richards][3]

“A research study, performed by Kathleen Liston of Stanford University, revealed that paper-based presentations demanded 40% of time spent at project meetings describing the .who, what, where, when, and how of the project, 20% explaining the rationale of the decisions made, and 30% evaluating goals to be sure project requirements are being met (Sawyer, 2005). Only 10% of time remained for the decision-making phase, where predictive questions like .What happens if we did this? could be asked and pondered (Sawyer, 2005). Better information delivery through the use of the 3D model, combined with schedule and budget information, could end having to sort through countless papers and increase the productive thinking time to 50%. An added benefit is that alternatives, changes, or adjustments could be discussed at the project meeting without having to return to the topic at another time just to present it.”[4]

BIM features:

BIM-Diagram

The most striking feature of BIM is that it has the whole life cycle of the building from the initial design to the completion. All the changes made during the cycle is automatically coordinated to all the disciplines and the final product will be accurate. So this helps in saving a lot time making the work easier, effective and also reducing the errors due to miscommunication. This leads to sustainable design. By making use of BIM, engineers can spend lot of time on design work and various other ideas than wasting time in making corrections thereby increasing the efficiency. BIM also decreases the risks of losing information when it is passed from one engineer to another .

According to Jim Jacobi (2006), principal of Water P. Moore : “Building information modelling significantly improves the quality and accuracy of the information that we push downstream. Our constructions documents are created directly from structure models, if that

model is correct, then the drawings are automatically correct. As result, we can able to spend a lot less time producing documentation and more time up front modelling the structure.”

Building information model had all the deatails of the building. The details being details of the project site, type of meterials to be used, Electical details, Energy consumption etc. The BIM model starts with the information from the clients initially followed by the geometry based on the requirements unlike the traditional method. So this method used is totally different from the traditional method which is followed now.

The concept of BIM is to create a virtual model of the building before it is actually being constructed so as to have a digital representation of it and so the designers can work on it and simulate and analyze the impacts to avoid wastage of time and to save time.

“Building Information modelling gives an access to following information on the following phases of the Project

• In the design phase—design, schedule, and budget information\

• In the construction phase—quality, schedule, and cost information

• In the management phase—performance, utilization, and financial information.”[2]

The ability of BIM to have an update of all the information in an intergrated environment Gives the Architects, Engineers and owners the overall vision of the project and thereby improving the quality of the work and also saving time.Since BIM runs through whole life cycle of the building it has an impact on all fields of the building industry. Everyone in the construction industry will have an advantage over this.The architect will have a smooth progression from conception to completion and the construction engineer has more efficient

way of working as he uses integrated modelling for design, analysis, coordination and documentation.

BIM is not a software or a technology, it is a concept and it requires suitable technology to implement it. There are so many software packages available but they are all in their unique format. There requires a date model which can support various packages so as to exchange the data from one discipline to another. It means it needs a common database for all disciplines to work without which BIM is just a concept and cannot be implemented.

IFC( Industry Foundation Classes) is a solution for this. IFC is a building data model which is widely used. There are so many other data models like Autodesk Revit, Bentley Architecture etc which are very popular in the industry. IFC is non- proprietary data model while the others mentioned above are proprietary i.e the engineers and architects have to pay to exchange their building information.

IFC is an open data model created by buildingSMART for interoperability in building industry and it is not controlled by single or group of vendors. Since its non proprietary engineers and architect can pass their information without paying. IFC is the most commonly used interoperability tool for building information model.

People using BIM will save money,time, reduced errors and increase in efficiency. However, many companies have taken a wait and watch attitude about BIM, looking for evidence for return n investment it entails.

Energy Analysis:

Everyone consume considerable amount of energy every day. All the day to day activities requires energy which implies to construction industry as well. In today’s world all the cities are flooded with buildings . That is the place where we spend most of the time. Buildings consume about 40% of energy and energy consumption is the main cause of green house gases. The more energy efficient buildings, the more good for people.

According to International Energy Agency “ Energy efficient buildings, industrial processes and transportation could reduce the world’s energy needs in 2050 by one third, and help controlling global emissions of green house gases.” During the last 30 years building sector has increased its energy consumption more than any other sector. So constructing more green buildings can reduce the energy consumption from civil industry. A green building is one which uses less water, optimises energy efficiency, conserves natural resources, generates less waste and provides healthier spaces for occupants, as compared to a conventional building. It encompasses concern for energy efficiency, environment, water conservation, use of recycled products and renewable energy. Green building helps in reducing the operation energy cost from day one and also gives various benefits like reduction in water cost, safety benefits and healthy life.

Energy problem has become a major problem for all the countries and they are taking various steps to promote green buildings. Government have started giving ratings to green building. In the United States Leadership in Energy and Environmental Design (LEED) is used to rate the green buildings which is the most prevalent rating system used by those accruing green building certification. And also various other countries have started their own rating system like BREEAM in United Kingdom.

There were so many energy analysis tools available to design energy efficient buildings but they were not used effectively as they were used in the later stages of the construction. If the energy analysis was made in the later stages of the construction and if there were some changes to be made in the design of the building, it was not possible as the construction is already in progress. So this was a hurdle to create energy efficient buildings. But in BIM initially virtual design is made before the actual construction. So it is possible to make an energy analysis on that so that changes can be made in the initial stages itself which will be automatically coordinated as everyone work on a same database So with the help of BIM, energy efficient buildings can be constructed.

BIM and Energy Analysis:

“In a perfect world, energy simulations and design tools would be so well integrated that each time an architect moved a wall, added a window, or changed a lighting specification, the building’s predicted energy performance would be updated and displayed instantly. With that sort of real-time feedback, designers would quickly become skilled at optimizing the energy performance of their designs, and new buildings would be rapidly approaching carbon neutrality. Along the way, other aspects of a building, such as how well it uses daylight, how procuring its material will affect the planet, and even how much it will cost to build, could be similarly tracked and optimized. And all of this would be done while sharing a design seamlessly across disciplines.” [ Nadav malin]

This world is not arrived yet but in future this can be achieved. Thanks to the concept of BIM. Although it is very expensive to implement BIM, designers and contractors are very keen to adopt BIM as it can reduce errors, cost and saves lot of time. This can result in Green Building.

BIM offers the capability to assess energy analysis in the earlier stages of the design. The energy analysis can be done with the energy tools available. For many years there are many energy simulation software tools available but the energy analysis is done late in the design when other important design features cannot be changed. The ability to model energy decisions early in the design process, and then choose the best alternative, is not fully exploited due to the difficulty and expense of modeling the building and energy systems after the design is complete. Many vendors provide several tools to conduct energy analysis with the data from BIM

Stand alone energy analysis tools:

These tools are available in the industry for many years but it is time consuming and costly process because the building model from the BIM tool have to be recreated for energy analysis. Hence this is a very time consuming process and are mostly used late in the design process for documenting energy decisions.

Industry Foundation Class( IFC)

IFC was found to be a solution to export the BIM data into energy analysis tool. The export was successful but there were some limitations in this process.

Current BIM models do not contain all the information necessary for energy modeling.

The export to IFC may lose some important energy related building data.

Several researches are being conducted by vendors and organisations such as International Alliance for Interoperability (IAI) and National Building Information Modelling Standard (NBIMS) to slove the above issues.

To improve the interoperability between the project design teams, the heating, the ventilating and air-conditioning (HVAC) has adopted Green Building XML (gbXML) file format. Several of the leading BIM applications enable users to create BIM output in the gbXML format (including Autodesk, Graphisoft, Bentley Systems, Elite Software, ECOTECT and GeoPraxis).

Green Building Studio, a web-based service that works with a gbXML file exported from

various BIM applications, uses the building information to perform an energy evaluation

with established tools such as DOE-2, eQuest, and EnergyPlus. Its “Design Alternatives” feature quickly analyzes the building to determine which option is the most energy-efficient by demonstrating various changes to the building design such as orientation, glazing options, envelope constructions, lighting, and HVAC.

According to Richard Grulich, chief of the Architectural Branch at Huntsville

Engineering and Support Center, “One of my greatest design experiences has been our

introduction to BIM. Our first BIM design for a medium size child care center is affording

a unique opportunity to incorporate early LEED planning into the three-dimensional

model. The working drawing aspect of BIM also identifies quantities and cost

projections. The missing component is an energy analysis tool that can be used when

the building envelope is developed within the first three weeks of the project. Testing

different geometries, orientation and envelope insulation scenarios will save time and design rework costs”.

Energy Plus:

Energy Plus is a program which does energy anlaysis and thermal load simulation. Based on the clients description of the building, Energy plus models heating, cooling, lighting, ventilating, other energy flows and water of buildings. Energy plus has evolved from BLAST and DOE-2 programs. BLAST (Building Loads Analysis and System Thermodynamics) and DOE–2 were both developed and released in the late 1970s and early 1980s as energy and load simulation tools to reduce the building energy consumption in the early 1970’s energy crisis. Some of the features of energy plus are:

Integrated, simultaneous solution where the building response and the primary and

secondary systems are tightly coupled (iteration performed when necessary)

Sub-hourly, user-definable time steps for the interaction between the thermal zones

and the environment; variable time steps for interactions between the thermal zones and

the HVAC systems (automatically varied to ensure solution stability)

ASCII text based weather, input, and output files that include hourly or sub-hourly

environmental conditions, and standard and user definable reports, respectively

Heat balance based solution technique for building thermal loads that allows for

simultaneous calculation of radiant and convective effects at both in the interior and

exterior surface during each time step

Transient heat conduction through building elements such as walls, roofs, floors, etc.

using conduction transfer functions

Improved ground heat transfer modeling through links to three-dimensional finite

difference ground models and simplified analytical techniques

Combined heat and mass transfer model that accounts for moisture

adsorption/desorption either as a layer-by-layer integration into the conduction

transfer functions or as an effective moisture penetration depth model (EMPD)

Thermal comfort models based on activity, inside dry bulb, humidity, etc.

Anisotropic sky model for improved calculation of diffuse solar on tilted surfaces

EnergyPlus is not a user interface it is a simulation engine around which a third-party interface can be wrapped. EnergyPlus is not an architect or design engineer replacement. It does not check input, verify the acceptability or range of various parameters (expect for a limited number of very basic checks), or attempt to interpret the results. While many GUI programs assist the user in fine-tuning and correcting input mistakes, EnergyPlus still operates under the “garbage in, garbage out” standard. Engineers and architects will always be a vital part of the design and thermal engineering process.

The basic simulation concept in EnergyPlus is integrated simulation (loads systems and plant simulation within the same time unit). Its internal data model consists of object and their parameters, but does not represent a fully object oriented architecture. Its architecture itself is completely modular, which facilitates addition of new modules and functionalities, some of EnergyPlus modules are still in development, with more to come.” (Nadav Malin, 2007, Building Information Modeling and Green Design)

http://apps1.eere.energy.gov/buildings/energyplus/images/screen_shot_idf_editor.jpg

However energy plus is stand alone simulation program without a user friendly graphical interface. A number of graphical interfaces are available and of one such is Open studio for google sketchUp. Open Studio is a free plug in for google sketchUp 3D drawing program which makes it easy to create and edit the building geometry in energy plus input files. OpenStudio was created by the National Renewable Energy Laboratory for the U.S. Department of Energy.

 “A lot of designers prefer SketchUp early on because it’s such a facile tool,” noted Chris Leary, AIA, of KlingStubbins.

Designed to integrate with the SketchUp environment, the plugin allows you to use the standard SketchUp tools to create and edit EnergyPlus zones and surfaces. You can explore your EnergyPlus input files by using all of the native SketchUp 3D capabilities to view the geometry from any vantage point, apply different rendering styles, and perform shadowing

studies. The plugin allows you to mix EnergyPlus simulation content with decorative content such as background images, landscaping, people, and architectural finish details—all within the same SketchUp model.

“I could imagine that SketchUp would be a pretty good interface for making an EnergyPlus model,” said Kevin Pratt, director of research at KieranTimberlake.

The plugin adds the building energy simulation capabilities of EnergyPlus to the SketchUp environment. You can launch an EnergyPlus simulation of the model you are working on and view the results without leaving SketchUp.

Screenshot from EnergyPlus with OpenStudio. In the center of the screen is a large graphical display of the building being designed in EnergyPlus. The 3-story building is designed like an H, and color-coded.

 

“A smart team working on sustainable design will start looking at energy models before even designing the building,” noted Guttman, adding, “They may do a lot of analysis on preliminary, pre-architectural models.”

PROJECT PROPOSAL:

To create a 3D building model using SketchUp

Integrate the 3D building model into energy plus using existing sketch up plug in

Analyse the building for energy using Energy plus and study the result.

CONCLUSION:

WORK PLAN

Activity

Week

1

2

3

4

5

6

7

8

9

10

11

12

13

Literature review

 

To Learn how to use SketchUp

To learn how to use Energy plus

Create a 3D model by using SketchUp

Integrate the model into Energy plus

Run Energy plus to make energy analysis and study result

Write the final report for dissertation

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