Monday, September 21, 2009

Computer Modeling Simulation

Although computer simulation in building is a main key for the study of energy efficiency in buildings first thing to consider is understand the definition of the computer simulation. Computer simulation is create a model of a theoretical physical system, complete this model on a digital computer program, analyze the output, compare the result and finally choose the best option which can give the most efficient result.

Inside the overall task of simulation there are three main sub-fields such as “model design, model execution and model analysis.” Simulation has a principle of leaning by practicing. To learn about the system is better to first build a model then operate this model. The use of simulation is an activity that is as natural as a child who role plays. Children understand the world around them by simulating. The majority of their connections with other people, animals, objects and their environment are based on learn by practice as well as make a mistake and gain experience. For instance they don’t know by pouring the sugar on the table they can build a sugar cone until they experience it. It is an opportunity that nature gave them to use their natural ability to learn during process. As an adult some of these childlike manners are lost during the time but it brings back to us through computer simulation design. In fact computer simulation is the electronic equivalent of role playing and it serves to drive synthetic environments and virtual worlds.

Simulation and modeling can be directly use as a design tool for any type of building and it has become essential part of many designs. It is a powerful and significant tool because offers a way to understand and explore different alternatives in design, plans and/or policies. Also it is less expensive, time-consuming and more practical to work with. Main advantage of simulation is before a building constructed it will allow the designers to optimize the energy use and efficiency of the building. During the design process designers have a chance to ask different question about the project like What if? Or how about this instead of that? These questions give them the opportunity to make changes as much as they want instead of changing the actual system.

In addition, for the exciting structures simulation could become a very helpful tool with the urge to improve efficiency of the buildings. Designers can model exciting building and try to optimize the energy use by varying different parameters in the structure such as window location, insulation materials, materials used for shading, lighting system, HVAC and air conditioning. Designers can monitor or measurer the impact of these changes on the overall energy efficiency and recommend changes to be implemented in the structure. With the recent development in the analysis and design tools modelers are able to correlate the simulation results with data collected from the actual structure. This has filled the gap between analyses and experiment.

Modeling process is a connection between designer, computer model, input data, and output result. Since many aspects of models need a fair conclusion designer and the model should be strongly connected to each other. As an example in the design process designer make an individual decision about which data is essential to use, how much detail need to be involved during the process and how to make the model more efficient and useful for public. In each particular project designer take time and effort to understand and recognize the limitation inherent in the model formulation, identify the errors, make a correction in details, calculation their response and obtain the best result.

Each model is generally designed for the specific project because in each project designer build the model based on the information and data on that specific situation and condition which is not similar to other circumstance. Sometimes the final result is not what a designer expected and it is fixable by comparison between simulation results. Also designer can check the result in different programs to get the most reasonable answer. After comparing the result in the simulation process designer need to replaced the exciting program to the better program if “better data is existing, more precise or more revealing analysis is performed on the data and an alternative formulation data provides as much insight with as much precision and more efficiently (lower data requirement or faster computational speed)”.

In the simulation programs the level of details of a model is a subject to concern. The model is worked based on variety detail and existing data which is really important in the modeling. Different programs give an opportunity to designers to add different type of detail during modeling but they should consider how much and what sort of detail they need to put in. Adding up the incorrect details to the process will change the numbers in the report and the result will not be practical at the end. The inclusion of extra detail can mislead the people because in some cases it shows that model is too expensive to use or need too much data requirement. Another duty of designer is collect all available data for the project because model can not create an outstanding result if data information does not exist or it is not completed. Also need to remember that if data were updated during the time of the design process it is a designer responsibility to replace or update the old information with new data.

Design process in meaning is similar to the meaning of investigation during design. If two designers attack a same challenge although they would naturally start from different points and process by dissimilar way they reach the same conclusion at the end. But during the design process both designers need to consider the all options such as R values, insulation, and door and window area and building construction.

Model should not be similar to a container that we just add information into it. The value of the model is dependent on the quality of the data, the way of designer using it and the amount of the details. It is good to remember that in design process first requirement for modelers is patient because sometimes the result of the work is disappointing and designers need to redo the all process of the design, add additional data to the program or compare data’s to get a better result. In general designers have three source of difficulty during their design process including:” experimental error (or noise), confusion of correlation with causation and complexity of the effects studies.”

If modelers consider some basic principles in modeling they make the design process simpler. “Model simple, think complicated” which means model doesn’t need to be as complicated as actuality and designers can think complex during process and have a simple final model. It seems little bit confusing because knowing how much simple or complicated the model needs to be is not an easy option to manage and some experience would be helpful. “Start small and add” is a second principle. The third principle is “dividing and conquers, avoid super large models”. As Pidd – professor of management science in the management school of Lancaster University- recommended in his paper, this is a common advice given to all modeler who is trying to understand how a complicated system operates. Designer should be stay away from falling in love with data and try to be realistic about them is another principle. The last principle for designers is “model building may feel like modeling through. “

Simulation system design in each project is developed by different alternative. In passive solar system simulations are developed by conduction, convection, and radiation relationship which describe the heat flow rate occurring in a building. In simulation some loads are more complicated to estimate than others. For instance, cooling load in passive solar system is more difficult loads to estimate compare to heating loads on both small (hourly) and large (annually) scale. The reason is “first, the difference between indoor and outdoor air temperature is typically smaller in cooling application so that the effect of solar radiation absorption on building surfaces is significant. Second, the ambient temperature may oscillate around the desired indoor temperature causing building thermal capacitance effects to be important. Third, the significant portion of the cooling load may result from the removal of water vapor from the air.”

In computer simulation it is really difficult to control the all parts of the design process and no matter how sophisticated a computer model becomes many limitation remains and they arise from the numbers of aspects. The mathematical imperfection that exits in the solution process, the difficulty of accurately modeling impacts and the rough calculation of complex modeling structure are some example of these limitation computers modeling in the building design process.

Design tool for building generally is classified as simulation or correlations. Simulations provide information on system performance over short (hourly) intervals of time. Correlations offer estimate of long term (monthly or annual). One of the best ways to establish a most excellent building design is to use simulation directly as a design tool. With a correct formulated simulation program and sufficient meteorological data every thing can be estimated and predicted. Simulation programs have a big variety in design field and they are available to community to use. However architect, engineers, designers and others who need to use the modeling program are more comfortable to use some programs that give them more options to play around during the design process, simpler to use, user friendly with more economical price.

Simulation programmers provide several suggestions to new designers to help them to accomplish a better design in the less period of the time. Planning a high-quality of process is as important as a planning a computer design. The model produced should be documented and maintained and be available to all designers to compare the result with each other and use the best available option. Superior contact with other designer is required because understanding and communication would develop across design group boundaries. Be cautious about each small detail which is involved in the design process since wrong number can lead the result to the wrong direction. The design should be carefully "partitioned" in the design process since it is easier to manage for later design groups. Even if it is possible for a small group of people to design and build out the entire project at the architectural level it is not possible at later levels of design.

Tuesday, September 15, 2009

HVAC

The question is what HVAC is and why as an architect we need to be familiar with this system. Basically HVAC stands for Heating, Ventilation, and Air Conditioning and it is essentially heating and cooling systems in the building.

Choose the HVAC is the first priority in building system and use the right one which is size-appropriate to the building type is really important because achieve the high level of efficiency and human comfort is a main key in buildings. In addition, maintenance service and set up the accurate system, volume of the system not simple task for designers and architect. For example use the heating system which is too large or too small for the residential project will give an inefficient system that cost more money in long term of period. Also big air conditioner will make an uncomfortable climate inside the building plus extra cost to run. It is even more important for commercial building such as museum, aquarium, office building and skyscrapers because base on the size of the users of the building HVAC system have to be energy efficient and functional and it is also has to offer a healthy and safe place to consumers.

The main job of HVAC system is to control room humidity and temperature. Since the uncomfortable place can influence people’s abilities successful control of those factors will minimize health related problems. High humidity reduces strength in human body which typically causes tiredness as well as “hypothermia, heat stroke, and hyperpyrexia”.

HVAC system has different jobs. Heating job is important in maintaining room temperature especially during colder climate. There are two different type of heating system such as local and central. Central more frequently used because it is economical and safe. Ventilation job is the process of changing air in public or private spaces. It manages temperature and eliminates humidity, smoke, dust, extra heat and bacteria. It let carbon dioxide to go out and oxygen to get inside and make sure the air is circulating and people are getting fresh and clean air. The air-conditioning system and refrigeration job is managed the both heat and ventilation. It works base on the proccess of radiation, convection, and conduction. It means by removing the heat from the area make the place more pleasant for indoor user.

LEED

LEED or The Leadership in Energy and Environmental Design is a global standard green building certification system which offers a new standard for environment friendly and sustainable design. It developed by the U.S. Green Building Council (USGBC) in United States at 1994 and provides a service to architects, engineers, developers, building owners and other industry leaders. It is also covers the building design, construction, operations and maintenance solutions. LEED has a different certification standard such as new construction and major renovation projects, existing building operations, commercial interiors projects, core and shell projects, homes and neighborhood development.

Comparing LEED certified building to other building which built base on building code; LEED regularly use resources more efficiently than others and frequently offers more eco friendly option to environment. Building types in LEED are includes offices, retail and service establishments, institutional buildings such as libraries, schools, museums and religious institutions and also hotels and residential buildings. LEED system provides the service to all 50 states of the United States and 91 countries and more than 40.000 projects are contributing.

LEED service works base on points. In face, “there are 100 possible base points plus 6 points for innovation in design and 4 points for regional priority”. Some of the categories are sustainable site 26 possible points, water efficiency 5 points, materials and resources 14 points, indoor environmental quality 15 points. Also each section divided by smaller option. For instance sustainable site has some option such as construction activity pollution prevention plan which is required, site selection 1 point, storm water manegment 2 points, reduse heat island 2 points, light pollution reduction 1 point and etc… By adding points building can be qualify for four special level of certification including Certified - 40-49 points, Silver - 50-59 points, Gold - 60-79 points, Platinum - 80 points and above. It is really user friendly service and after submitting an application online with documents and requirements consumer pay registration and certification fees and certification is going to process and decided by the Green Building Council.

Buildings including residential and commercial are account for 40% of energy usage and CO2 emissions and designing an eco friendly building is necessarily in our decade. Thus it brings a big responsibility to architects and other people who are involved in building industry. By having a good standard certification system architects could achieve their goals which is using less energy, water efficiency, greenhouse gas emissions reduction, CO2 emissions reduction and gaining healthier environment for all community.

ENERGY STAR

It is a worldwide standard program which created by United State Department of Energy and United State Environmental Protection Agency. This program is planned to recognize and promote energy efficiency of products, reduce greenhouse gas emission, reduce global warming gases, protect the environment, save money and energy for consumers around the world. This standard start working at 1992 in the United State by labeled computer and monitor and then they extended their service by labeling the additional office products, residential and commercial heating equipment, residential air conditioning, home electronics, and lighting products. Since the success of this program in United State was more than community expected, numerous European countries decided to adopt it as well. Due to the research any equipment which meets the standard and gain Energy Star Logo can save 20% to 30% on energy usages on average.

The Energy Star designed to use for residential, industrial and commercial. In fact using the service for residential can save at least a third on families’ energy bill and also for business can create twice the saving. For example last year Americans saved $19 billion on their utility bills plus improved home comfort. In addition they gained even more benefits such as tax credit from state and federal, avoid greenhouse gas emissions and protect the environment. ENERGY STAR could effectively delivered energy to businesses, owners, designers and organization and saved money for them. Also influenced companies to use more efficient product such as fluorescent lighting, LED lighting (Light Emitting Diode) and low standby energy use. Fluorescent lighting uses 70% less energy than other lights and lasts up to more than ten times longer than normal incandescent lights.

One of the popular services of Energy Star is for entertainment sector. Probably we never imagine that saving energy will be a possibility when we go to museums, theater, stadium or convention center. ES has online tools and resources for entertainment industry and guides them to greener environment. Quick Reference Guide to Benchmarking, Webinars, and news articles about managing energy and being green are some of their tools. St. Louis Cardinals’ Busch Stadium and Virginia Beach Convention Center are two good examples of this service.

In the last decade energy prices turn to be a hot topic and a main alarm for community and also finding a trustable standard was not easy. Energy building by labeling equipment with better performance for each business and organization could open a new chapter in energy efficiency and cost savings. It brought a better product for better world.

Sustinable design...

01. The First Law of Thermodynamics is energy into the system = useful energy which is delivered + wasted energy. Energy efficiency is useful energy out divided by energy input. By achieve a bigger number from this calculation we increase our efficiency. For example by using a compacts fluorescents bulb in the house we can increase the efficiency

02. Buildings consume over 40% of the total energy and it is growing fast than we can imagine, this number by 2030 will enlarge to 55%. Current model for home use 190 thousand joules per square meter and the best prototype is 11 thousand joules per square meter which can make a big deference in saving energy. Most primary energy uses in US are lighting (for commercial sector 25.2% and residential sector 6.8%) and space heating and water heating (for residential sector 39.8%, 16.9% and commercial sector 32.4%).But climate make a big difference. For example in Phoenix area air conditioning has a bigger number compare to space heating. Data from US department of energy and Hunn Chapter 01.

03. ENERGY STAR Program is a program which “voluntary labeling program designed to identify and promote energy-efficient products in order to achieve long-lasting market transformation.” It is cover the entire building sector like office equipment, residential, new homes, commercial buildings, major appliances, home electronics, windows and also residential and commercial lighting.

04. LEED Green Building Rating System which is a national standard for sustainable buildings. It is Some LEED certification standards are New construction and major renovation projects (NC), Existing building operations (EB), Commercial interiors projects (CI), Core and shell projects (CS), Homes (H) and Neighborhood development (ND)

05. Simulation Programs is a building thermal simulation which allows us to model a building before or after renovations. Also give a chance to architects and designers to try different energy alternatives, compare them and use the best option. It is more economical and less time consuming.

06. HVAC = Heating, Ventilating and Air Conditioning. HVAC systems help to control the climate and humidity and keep dwellers comfortable by regulating the temperature and air flow.

Climate change motivation...

Climate change bring different question to peoples mind. What is the definition of the climate change? Is it the certain countries inaccuracy? What is the responcibility of the public? And how individuals can help? Although climate change is not a short term change and it happened over periods of time that range from decades to millions of years in current decade is become a huge intricate for the world. Some people even believe that climate change like global warming is out of control and no one has power to change the fact.

The climate-change motivation is have a discussion in three things. First “human fossil fuel burning causes carbon dioxide concentrations to rise, Second carbon dioxide is a greenhouse gas and third increasing the greenhouse effect increases average global temperatures (and has many other effects).”

Carbon dioxide was rising during the time (1000AD to the present) but after the Industrial Revolution from (1800AD to 2000AD) the increase rate has been exponential. It started increasing when James Watt introduced his steam engine to the society. At the same time British coal production started to go up as well. Coal production was used to create iron, to build and power transportation system like ships and locomotive and to heat up houses. The usage of the coal production was growing extraordinarily. For example in the 30 years from 1769 to 1800, yearly use of coal production doubled and then in 1830 it had doubled again and then in 20 years later doubled again and still continues. It was not just happening in England, in other countries same thing was starting after industrial revolution. In producing CO2 emissions oil production is slightly less effective than the coal.

Since people were successful by doubling or tripling CO2 concentration lot of things will be changed in the future. First increasing the intensity of the sun by 2%, second global temperature goes up almost 3 ◦C. third “the Greenland icecap would gradually melt, and, over a period of few 100 years, sea-level would rise by about 7 meters.” The last and not least is changing the ecosystem for humans, animals and plants.

Why it is important to use numbers in planning and policy debate?

Planning and policy debate is basically attached to the numbers and often questions can make a better explanation by numbers. When people are not aware of the amount of energy they use in a day the influence of using extra energy in the community will be harder to recognize for them. In addition by numbers they will have a better view of the amount of the each energy source in surrounding and the cost of it. One of our goals is decrease energy consumption in the world and to achieve this target it is better to use simple and acceptable numbers.

Simple numbers are more understandable, memorable and easier to compare information together. Apply the adjective instead of numbers will confuse public about reality. For example use “huge” as an alternative of actual amount. Using the acceptable number is as important as using simple numbers. Employ a huge number especially when it is not necessarily can be meaningless to the public. For example “American buys 2.6 billion napkin boxes per year” is not inform people but “Switching your gas and electricity supplier could save you up to $340 a year” is more real and practical.

Since sometimes numbers are selected to impress, change the fact, arguments or scare people instead of educating them using number when it is not a need can bring distrust to community. For instance in a climate when public don’t pay attention to numbers mass communication media such as news papers, radio and companies can provide wrong information.

Different questions about renewable energy, climate change, dioxide pollution and energy crisis are easier to explain with numbers. Some questions are: can people make a difference in the energy crisis by biking or walking instead of driving a car? How much energy efficiency will increase by using fluorescent lighting and LED lighting (Light Emitting Diode) instead of regular lighting? How much carbon dioxide pollution will reduce by changing our life style to advanced technology like hybrid car?