The objective of building simulation is to predict, at the design stage, aspects of a building's performance such as its thermal, lighting and structural behavior. It involves developing mathematical models to represent the physical process occurring within the built environment. Typical of system applications are include energy analysis system, lighting analysis systems, HVAC systems, structural analysis systems and are usually used by building services engineers during the design stage. All construction professionals need to appreciate their importance in ensuring the quality of building design.
Based on one case study ( construction project ), highlight the significant building simulation to construction industry and how it's being applied during design stage.
Simulation means to create certain conditions that exist in real life using computers, models and others. Building simulation means that prediction by the building services engineer during design stage consist of energy analysis, lighting and HVAC system. Building Simulation also refers to the process of dynamically analysis a building's energy performance through the use of software simulation and computer model techniques. It involves the calculation of thermal loads and energy consumption of the building in order to determine its energy flows and characteristics. It is important to simulate accurately during design stage for the performance of that building.
This stage can help building services engineer evaluate few alternative design solution to reach optimum design and also comply with building regulations requirements. To design analysis and simulation, the first things that must focus on the use of such application as part of the normal performance assessment process during detailing building systems in the later stage of design. In contrast to the earlier applications, the applications in this phase are complex and usually operated by technical domain specialist. The design should consider areas of application and existing software alternatives, some of the issues concerning their use and exchange, integration methods and general concerns relating to collaboration. These stages conclude by examining the special use of analysis and simulation models that explore innovative applications of new technologies, materials, controls or other systems to buildings. It is importance to note that such experimental architecture generally requires specialized tools and configurations.
The process of Building Simulation has the following objectives:
To optimized the use of resources
To minimized building life cycle cost
To ensure a comfortable indoor environment
Analysis / simulation software
The early stages of the design process are where most of the important decisions impacting on building environmental performance are made. Designers need analysis software that quickly provides answers to questions about lighting, air-conditioner, overheating, natural ventilation and others. As design development proceeds, details concerning the building's various systems must be determined in order to validate earlier estimates and to specify the systems for bidding, fabrication, and installation. This detailing involves a wide range of technical information. All building must satisfy structural, environmental conditioning, fresh water distribution and waste water removal, fire retardances, communications and others basic functions. While each of these capabilities and the systems required to support them maybe have been identified earlier, their specification for conformance to codes, certifications and client objective required more detailed definition. In addition, the spaces in a building are also systems circulation and access, systems of organizational functions support by the spatial configuration. Tools for analysis of these systems are also coming into use.
Role of Building services engineering on design simulation
Building services engineering is the engineering of the internal environment and environmental impact of a building. It essentially brings buildings and structures to life. Building services engineers are responsible for the design, installation, operations and monitoring of the mechanical, electrical and public health systems required for the safe, comfortable and environmentally friendly operation of modern buildings.
INTRODUCTION TO CASE STUDY
To complete our task, we had chose Auditorium Bandaraya at Dewan Bandaraya Kuala Lumpur, Menara DBKL 1, Jalan Raja Laut. The Auditorium situated at the right of entrance or main lobby. Auditorium DBKL was recently refurbished and reopened to host various events in the heart of Kuala Lumpur. Dewan Bandaraya Kuala Lumpur or Kuala Lumpur City Hall (DBKL) is a local authority which administrates Kuala Lumpur city centre and other areas in the Federal Territory of Kuala Lumpur. There are two DBKL main headquarters which are DBKL headquarters at Jalan Raja Laut and Menara DBKL 3 at Jalan Raja Abdullah. This agency was formerly known as Majlis Bandaran Kuala Lumpur or Kuala Lumpur Municipal Council. When Kuala Lumpur granted its city status on 1 February 1972. The name changes to Dewan Bandaraya Kuala Lumpur or Kuala Lumpur City Hall (DBKL). And two years later, it became the Federal Territory of Malaysia on 1 February 1974.
SIGNIFICANCE OF BUILDING SIMULATION IN CONSTRUCTION INDUSTRY
Building simulation is very importance task. This is because of its importance to maintain all the services in specific building. Clients or owner of that building in construction industry have their own desire and want their building can give value of money. Then, they want their building to look in good visually, high of aesthetic value, to be safe structurally, to provide comfortable living environment. They also want the building less of maintenance that means must use quality goods and services. The simulation must be operate perfectly and always in good condition. Hence, the designer should design the simulation perfectly because of the importance the simulation to the building.
The significance of building simulation was on design stages in construction. The development of dynamic building simulation programs has resulted in high levels of modeling capability. This enables simulation experts to provide building designers with quality information in areas where they previously had to rely on experience , use simplified calculation methods or apply rules of thumbs. Building simulation was used during design which is on scheme design, detailed design and production of information. To establish a holistic design approach with simulation having an input at all stages it was necessary to determine the design approach of the architecture practice used a test bed. Different design objectives and scope can be observed in the different building design stages. The aim was to identify for the different stages key parameters that are part of the designer's consideration.
On the scheme design stage, purpose of the work is to determine the general approach to the layout, design and construction in order to obtain authoritative approval of the client on the outline proposals. The project brief will be fully developed and detailed proposals will be made and compiled, generally in a "Stage D" report. The application for full development control approval will be made at this point. For the simulation, the outline design stage proposal was approved by the client is now taken to a more detailed level. Tangible material produced can include site layout, planning and spatial arrangements, elevation treatment, construction and environmental systems. Simulation will focus on problem areas or on typical building sections. In terms of environmental simulation this stage can be seen as a load reduction stage with the designers having more time available to spend on certain issues. Simulation parameters also relate more to the building envelope ( glazing properties and ventilation rates ).
While on the detailed design stage, Completion of the brief with decisions made on the planning arrangement, appearance, construction method, outline specification and cost of the project. All approvals will be obtained at this stage, including for Building Regulations. In effect, during this Stage final proposals are developed for the Project sufficient for co-ordination of all its components and elements to realize the construction and now the approved scheme design solution is worked through in detail. Detailed design drawings are produced for co-ordinating structure, services and specialist installation. Internal spaces may be detailed to include fittings, equipment and finishes. At this design stage, the application of simulation relates mainly to engineering issues and it will be experts using the tool. They will use simulation for purposes such as designing a natural ventilation strategy ( sizing openings, establishing control strategies, confirming minimum and maximum air flow ) or to model other building services applications such as chilled construction systems or air-conditioning systems.
On production information stage, final decisions taken on every matter related to design, specification, construction and cost. For a traditional procurement process, production information is first prepared in sufficient detail to enable a tender or tenders to be obtained. Any further production information required under the building contract to complete the information for construction is then prepared. All statutory approvals should be obtained by the end of this phase. On this stage all the designer on simulation had choose what the design they want use and tools/software for the building application and services such as lighting, sound and air-conditioner.
LIGHTING ANALYSIS SYSTEMS
Comprehensive lighting design requires consideration of the amount of functional light provided, the energy consumed, as well as the aesthetic impact supplied by the lighting system. Some buildings, like surgical centers and sports facilities, are primarily concerned with providing the appropriate amount of light for the associated task. Some buildings, like warehouses and office buildings , are primarily concerned with saving money through the energy efficiency of the lighting system. Other buildings, like casinos and theatres, are primarily concerned with enhancing the appearance and emotional impact of architecture through lighting systems. For our task, Auditorium bandaraya's light must be considered on two types of lighting whereas light for the hall and the stage.
Therefore, it is important that the sciences of light production and luminaire photometrics are balanced with the artistic application of light as a medium in our built environment. These electrical lighting systems should also consider the impacts of, and ideally be integrated with, dayHYPERLINK "http://en.wikipedia.org/wiki/Daylighting" lighting systems. Factors involved in lighting design are essentially the same as those discussed above in energy conservation analysis. For simple installations, hand-calculations based on tabular data can be used to provide an acceptable lighting design. More critical or optimized designs now routinely use mathematical modeling on a computer.
Lighting of stage
Modern stage lighting is a flexible tool in the production of theatre, dance, opera and other performance arts. Several different types of stage lighting instruments are used in the pursuit of the various principles or goals of lighting. Stage lighting has grown considerably in recent years partially due to improved technical equipment and a higher interest from young people.
Stage lighting has several functions, although to allow for artistic effect, no hard and fast rules can ever be applied. The functions of lighting include:
Illumination: The simple ability to see what is occurring on stage. Any lighting design will be ineffective if the viewers cannot see the characters, unless this is the explicit intent.
Revelation of form: Altering the perception of shapes onstage, particularly three-dimensional stage elements.
Focus: Directing the audience's attention to an area of the stage or distracting them from another.
Mood: Setting the tone of a scene. Harsh red light has a totally different effect than soft lavender light.
Location and time of day: Establishing or altering position in time and space. Blues can suggest night time while orange and red can suggest a sunrise or sunset. Use of gobos to project sky scene, moon etc.
Projection/stage elements: Lighting may be used to project scenery or to act as scenery onstage.
Plot(script): A lighting event may trigger or advance the action onstage.
Composition: Lighting may be used to show only the areas of the stage which the designer wants the audience to see, and to "paint a picture".HYPERLINK "http://en.wikipedia.org/wiki/Stage_lighting#cite_note-1"
While Lighting Design is an art form, and thus no one way is the only way, there is a modern movement that simply states that the Lighting Design helps to create the environment in which the action take place while supporting the style of the piece. "Mood" is arguable while the environment is essential
Design stages for lighting
For setting up the lighting system in the Auditorium DBKL, firstly it based on the environment of the event that usually takes place at the auditorium. Most of the commercial events such as theatre, concert and dance usually take place here. 12- 20 lighting fixtures were installed in this auditorium. At the above of stage, it use PAR 56 lamp that has 300W and PAR 64 with 1000W. For the above audience, this auditorium uses Philips and Osrem lamps with 25W. There are 7 lamps in a line and there are 4 lines above the audience. The light distances to the stage range is 50 feet. Besides, there are also additional lighting fixtures used such as emergency lights. The emergency lights are installed at the left and right sides of the auditorium. There are 6 overall. The emergency lights are also installed at the risers of the staircase. This auditorium only installed the main lighting system needed for any events, as for the additional, like spot lights and flood lights, the organizer of the events will provide it by themselves.
Advantages of the design
The lighting systems installed by the lighting designers give advantages such as :-
It provide illumination
It can suggest mood for the performers and audience
Emphasize in shape and textures
Allow audience's to focus at the area they want
As a supplement for the general lighting
Provide specific lighting effects
Provide sense of time and place
Software for lighting
This is a list of Lighting Design software for use in analyzing photoHYPERLINK "http://en.wikipedia.org/wiki/Photometrics" metrics, BIM (Building Information Modeling), and 3D modeling. The software is typically used by importing the structural design via CAD files. Then lighting elements are inserted. And finally, the lighting objects are associated with a photometry via IES files. The photometry of a light fixture describes the way it distributes its light into space. Once this process is completed, the illuminant and luminance produced by each fixture in the space can be calculated. The output is typically a diagram indicating these by means of colors or numbers. This typically is the goal of technical photometry software. In marketing and higher-level design, 3D photometric analysis is useful to give a graphical output of a proposed design.
While lighting simulation based on computational fluid dynamics ( CFD ) had their own particular data needs. Computational fluid dynamics (CFD) is one of the branches of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows.
Computers are used to perform the millions of calculations required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. Even with high-speed supercomputers only approximate solutions can be achieved in many cases. Ongoing research, however, may yield software that improves the accuracy and speed of complex simulation scenarios such as transonic or turbulent flows. Initial validation of such software is often performed using a wind tunnel with the final validation coming in flight tests.
This is the first step in building and analyzing a flow model. It includes building the model within a computer-aided design (CAD) package, creating and applying a suitable computational mesh, and entering the flow boundary conditions and fluid materials properties. We supply our customers with preprocessing tools such as GAMBIT, THYPERLINK "http://www.fluent.com/software/tgrid/index.htm"-Grid and G/Turbo as standard. But, we also have very good filters to nearly every other third-party preprocessing tool available in the market today.
The design consideration for any air conditioning system depends largely on its application. It is a known fact that auditorium is high occupancy (persons per square feet) areas. Consequently, the fresh air requirement is high in order to dilute the CO² concentration. High occupancy also leads to a greater amount of latent load emitted by the human beings. All these considerations need to be factored into by the designers while calculating the air conditioning load. The inside design condition is as per ASHRAE standard for human comfort.
Another important criterion is the noise and vibration control. The desired Noise Criteria (NC) varies with the type and quality of the facility. The need for noise control is important in auditoriums. In most cases, sound and vibration control is required both, for mechanical equipment and the air distribution system.
Generally, the seating area of auditorium is isolated from the exterior by lobbies, corridors, etc. In the seating area, people generally remain in one place throughout the show or talk on the stage. A good air distribution system ensures that air reaches the entire seating area without creating drafts and noise. There are multiple options of locating the supply air ducting and return air (ducted or otherwise). The most common and possibly the best method is to locate the supply air duct at the ceiling level and distribute the air uniformly through ceiling diffusers, the design of which will depend on the height at which duct is located. The return air can be located below the seat and ducted back to the air handling unit room through trenches in the floor. This layout of air distribution would ensure uniform distribution of air without draft and noise. In a low noise requirement, it is advisable to acoustically line the supply and return air duct completely with fibre glass wool of adequate thickness.
Another alternative is to locate the supply air duct along the sidewalls of the hall. The duct can be concealed in boxing and the supply air grilles can be either continuous or conventional. The grille is to be designed for adequate throw so that air reaches even the central portion of the seating area.
However, very large halls require larger throw from the sidewalls. In such installations, selection of the grille is very important to meet the throw requirement. Generally, this results in a high air discharge velocity leading to noise as well as draft. Therefore, it is recommended that supply air throw should be designed for a maximum of 30 ft throw from the side and to ensure it reaches the central portion of the hall, the return air should be collected below the seat. Another alternative to take the return air is directly below the stage, and this method is quite commonly followed.
Location of mechanical equipment such as Chillers, Air Handling Units, and Pumps etc. is quite critical, particularly, where low noises criteria is a key requirement. It is advisable to have the air conditioning plant room and the air handling unit room in a separate area, which is structurally isolated from the auditorium. The locational constraints sometimes force us to accept an air handling unit room within the same structure as that of the Auditorium and sometimes very near the Auditorium.
It is essential to ensure, that in such installations, the air handling unit (AHU) is mounted on correctly selected vibration isolators and the chilled water pipe is provided with a flexible connection to avoid transmission of vibrations to the structure. It is preferable to have AHU fans of backward-curved type and the bearing of nylon pillow block. A double-skin type of AHU is always preferred for low noise application. It is important to acoustically line the walls of the AHU room. Sound attenuators should be provided both in the supply air duct as well as return air path. Wherever return air is not ducted, it is recommended to have the return air attenuator on the return air opening of the Auditorium wall.
In order to increase cooling capacity, we can simplified that heating, ventilating, and air-conditioning (HVAC) systems for auditorium spaces are sized and zoned to accommodate varying internal loads, which are a function of audience sizes, performance lighting loads, and projection equipment.
Particularly, air handling unit (AHUs) with increased cooling capacity should be zoned separately for the auditorium lobby, projection stage, stage areas, and audience seating areas. Also, the auditorium typically has a separate AHU constant volume with modulated temperature control for ventilation. The recommended system for distribution of HVAC in auditorium space is ducted supply through floor vents with ducted ceiling return air vents in auditorium and lobby. In other spaces, ducted ceiling supply with return air ceiling plenum is recommended. There should be transfer ducts at all acoustically rated partitions.
Software of HVAC systems
The heat generated from the air-conditioning equipment or other thermal loads is distributed throughout a room by a three-dimensional airflow. This three-dimensional airflow creates a three-dimensional heat distribution in a room. To better understand building performance, we must integrate this spatial distribution into building simulations. Thus, three-dimensional computational fluid dynamics (CFD) analysis is necessary in design process because most conventional building energy simulations still employ a temperature that is averaged across the space of a room. However, usually only a few cases of CFD analyses are executable in real design process because of the large computational load they require.
This is a new and simplified method:
To calculate heat transport phenomena in rooms based on a few cases of CFD analysis and to integrate data into a nodal analysis.
To calculate an indoor environment, including the spatial distribution of temperature, with a computational load that is much lighter than it is in a simulation using CFD alone.
More reliable method than the conventional simulation in term of precision, which assumes the perfect mixing of heat in a room.
To simulate the control of air conditioning.
Ordinarily, the reproduction of the phenomena shown in the calculation examples requires substantial manpower and costly computing resources for experimentation or CFD analysis. With our calculation method, it is possible to reproduce the same calculation results in a very short time with a computer. We checked the potential to the practical use through a verification calculation with CFD analysis.
All the above principle and concept can be applied in our case study, Auditorium Bandaraya DBKL Menara 1, which has centralized air conditioning equipment. A computerized HVAC system connected to geothermal wells and threaded via plastic pipes throughout the wall system removes heat from the southern planes or cold from the northern planes. This innovative and original approach to an internally distributed sustainable mechanical system is unprecedented in its original conception.
Central Handling Unit
Central air handling units have a number of advantages as compared to unit ventilators and heat pumps serving individual rooms. They are:
Quieter, and therefore more likely to be turned on or left on.
Less drafty due to multiple supplies and a return that is away from occupants.
Better at controlling humidity and condensed moisture drainage.
Easier to maintain due to reduced number of components and few units to access.
More space around units and can be accessed without interfering.
Space for higher efficiency air filters, and more surface area.
Made of heavier duty components.
Less likely to have quantity of outdoor air supply inadvertently reduced.
In the DBKL Auditorium, the sound system was set up as such the audiences will get the maximum volume, within the range of human hearing. It was set up so that people can listen without having to concentrate on the music played, but also not too loud that can make the ears ache. The arrangements of the speakers in the auditorium are as follows:
A couple of main speaker are at the front, each are at the left and right of the stage, near the audiences front chairs.
A few speakers are placed on the ceiling, above the audience chairs, near the lightings and the air-conditional ventilations. This is to ensure that the audiences at the back will also get the maximum volume.
However, to protect the sound from escaping to the outside of the auditorium, the designers choose to make the wall from acoustic material. Not only will this trap the sounds from escaping, it also help not to carry outside sound from entering the auditorium.
Building simulation is currently not an integrated element of the design process. However, because of the complexity of the design process and the advanced technologies now applied in the building industry would be very desirable. Integrating modeling would raise awareness of energy and environmental issues and give it an adequate status in design decision making. Different design objectives and scopes can be observed in the different building design stages. Research was undertaken to identify for each design stage key parameters pertaining to energy and environmental performance that could be addressed by simulation. The concept develop is based on the use of one simulation program throughout the design process to ensure continuity between the different design stages.
Building services engineer should design and simulate the building accurately because it is very costly to re-design or to fix any design defect after the building was constructed. All the problems can be identified and solved during the design of the building performance. There are some typical of systems application includes in the building simulation so a variety methods have been develop to predict the simulation and performance in that systems application such as lighting, HVAC systems and others. The simulation system involves complex and needs some mathematical models to represent the physical process occurring within the built environment, it was not feasible to carry them out before computers were used. Since the building engineering application have been develop, it can help the designer to evaluate alternatives design solutions in order to get the best performance of the building and also achieve the optimum design whereas can save cost and client can get their value for money.