Bim Unit-03 Student Workbook 2011 FINAL

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Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design

Contents Unit Overview.....................................................................................................................3!

Key Concepts.................................................................................................................3!Lesson Roadmap ...........................................................................................................7!Software Tools and Requirements.................................................................................7!Suggested Resources....................................................................................................8!

Lesson 1: Passive Design...............................................................................................11!Lesson Overview..........................................................................................................11!Learning Objectives .....................................................................................................12!Suggested Exercises ...................................................................................................13!Assessment..................................................................................................................16!Key Terms....................................................................................................................17!

Lesson 2: Material Properties and Energy Impact........................................................18!Lesson Overview..........................................................................................................18!Learning Objectives .....................................................................................................20!Suggested Exercises ...................................................................................................20!Assessment..................................................................................................................22!Key Terms....................................................................................................................23!

Lesson 3: Water Use and Collection..............................................................................24!Lesson Overview..........................................................................................................24!Learning Objectives .....................................................................................................25!Suggested Exercises ...................................................................................................25!Assessment..................................................................................................................28!Key Terms....................................................................................................................29!

Lesson 4: Power Use and Generation ...........................................................................30!Lesson Overview..........................................................................................................30!Learning Objectives .....................................................................................................32!Suggested Exercises ...................................................................................................32!Assessment..................................................................................................................34!

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Key Terms....................................................................................................................35!Lesson 5: Daylighting......................................................................................................36!

Learning Objectives .....................................................................................................38!Suggested Exercises ...................................................................................................38!Assessment..................................................................................................................41!Key Terms....................................................................................................................42!

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Unit Overview Key Concepts Green building design is an approach to designing buildings that focuses on sustainability and the long-term environmental impacts of our design decisions.

People use terms such as green and environmentally friendly in many ways. There is no precise definition and a lot of confusion about what being green really means. The term has evolved to encompass a broad range of strategies, all motivated by the common thread of improving the sustainability of our built environment.

The World Commission on the Environment and Development offered this definition in 1987 to succinctly describe the guiding principle that motivates sustainable design:

Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs.

This definition still rings just as true today, more than 20 years later.

Motivation

Buildings play a huge role in annual fuel and energy consumption, as well as greenhouse gas emissions. In the United States, buildings consume 39 percent of the annual energy and 68 percent of the annual electricity. Buildings are also responsible for emitting 38 percent of the carbon dioxide, 49 percent of the sulfur dioxide, and 25 percent of the nitrogen oxides found in the air. Furthermore, buildings consume a substantial amount of water, depleting yet another valuable natural resource.

As a long-term goal, green building design aims to create sustainable, self-sufficient structures by using resources wisely and minimizing environmental impacts. By improving the design of buildings with this goal in mind, we can make significant improvements in our overall resource use and environmental friendliness. Throughout the entire lifecycle of a structure, green design aims to reduce resource consumption and minimize emissions and waste.

Green Design Strategies

Many strategies can be employed to improve the sustainability of our building designs. There is no single best approach, but the steps typically include:

Consider the passive architectural design featuresincluding building placement and orientation, massing and form, and the placement of windows and openingsto promote daylighting and natural heating and cooling.

Design the building envelope using materials that minimize energy waste and help to lower the carbon footprint.

Improve the efficiency of the active building systemsincluding lighting and power, heating and cooling, and water supply and wasteto minimize the demand for external resources.

Use innovative strategies to incorporate renewable and sustainable energy and water resources wherever possible and to reduce reliance on external sources.

Some popular approaches include:

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Selecting a sustainable site

Promoting alternate forms of transportation

Using water-efficient landscaping

Reusing wastewater

Harvesting rainwater

Using on-site renewable energy

Using local materials

Using rapidly renewable materials

Using system controls (for example, sensors)

Increasing ventilation

daylighting

While efficiency and sustainability are the main goals of green design, it is important not to forget the human aspects of a building. When designing a structure, there must be a balance between being environmentally friendly and being usable and comfortable.

Establishing a Green Design Goal

As design teams choose alternative green strategies, it is important to explicitly establish their goals and prioritize them. The goals selected can lead to very different design decisions.

One way to approach this challenge is to first decide what measures will be used to evaluate the effectiveness of an alternative:

Economic impact and estimated monetary savings

Environmental impact and estimated resources savings

Reductions in the size of the carbon footprint

Others

Then the team can establish the target levels of reduction for each of the measures selected to:

Reduce consumption to a target percentage below a baseline level.

Minimize impacts or offsetting them to have a net-zero impact.

Eliminate all dependence on external resources and going off the grid.

Any of these levels would be an example of a sustainable design and a net improvement compared to conventional designs. For this reason, we typically evaluate sustainability in relative, rather than absolute terms.

LEED

The United States Green Building Council (USGBC) created a green building rating system to help promote sustainable building practices. This system is known as LEED, an acronym that stands for the Leadership in Energy and Environmental Design.

The LEED rating system, which defines standards for measuring how green a building is, encourages building designers, contractors, building owners, and product manufacturers to use sustainable practices by providing recognition for exemplary performance. It has

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also raised consumer and public awareness of good green design, which in turn encourages all participants to consider sustainability issues as design decisions are made.

Using the LEED rating system, buildings are judged and awarded points for these major categories. The evaluation system was changed in 2009, expanding the credits available in several categories and recalibrating the points required for each level of certification.

Category Points Available (Pre-2009)

Points Available (Post-2009)

Sustainable Sites 14 26

Water Efficiency 5 10

Energy and Atmosphere 17 35

Materials and Resources 13 14

Indoor Environmental Quality 15 15

Innovation and Design 5 6

Regional Priority N/A 4

Total 69 110

The following table lists the specific credits in each category and the points available per the 2009 changes:

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Based on the number of points or credits achieved, buildings are awarded a level of certification:

Certification Points Required (Pre-2009)

Points Required (Post-2009)

Certified 2632 4049

Silver 3338 5059

Gold 3951 6079

Platinum 52+ 80+

To supplement the materials provided in this curriculum, consider inviting local design professionals to your classroom to present case studies and share their experiences and insights from working with the LEED criteria and evaluation system. For example, consider:

How their project team used the LEED process and the design strategies in the design of a local building.

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How the target level of LEED certification was selected for the project.

Which LEED credits were selected as design criteria and how the measured improvements were achieved.

Providing real-world case studies of local building projects will heighten student interest and greatly improve the effectiveness and impact of the curriculum materials presented.

Lesson Roadmap In this unit, you will learn how to design and evaluate green design measures by exploring:

Passive Design

Building orientation

Building massing and shape

Architectural featureswindow placement, roof overhangs, and shading features

Building Envelope

Thermal properties of building materials

Thermal transfer

Thermal comfort

Water Use and Collection

Estimating the water demand baseline

Improving efficiency through plumbing fixtures

Offsetting water use through net-zero measures

Power Use and Generation

Estimating the electrical demand baseline

Improving electrical efficiency through fixtures and controls

Offsetting power use through net-zero measures

Payback period

Daylighting

Analyzing daylighting levels provided through architectural features in the building model

Implementing daylighting design strategies

Software Tools and Requirements To complete the exercises in this unit, you should download the following software programs and install them on you computer and register for the following services:

Download Autodesk Ecotect Analysis software from the Autodesk Education Community website.

Access Autodesk Green Building Studio web-based energy analysis service from the Autodesk Education Community website and create an account.

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Download the Autodesk Green Building Studio Client software from the Green Building Studio web service page to upload building models and designs for analysis.

gbXML: Green Building XML Schema

The gbXML Scema was designed to transfer essential information contained within a building information model. This information includes items such as walls, windows, and room areas, and excludes superfluous items such as furniture, stairs, and appliances.

This format allows for a consistent way to share information between Autodesk Revit products and other software tools that adopt the schema. In the following unit, we will be saving our models as gbXML (green building extensible markup language) files in order to transfer data into Ecotect Analysis and Green Building Studio.

Autodesk Green Building Studio

Green Building Studio is a web-based service for use in evaluating the environmental impact of your building design and design alternatives. While the program accounts for location-specific weather data, and reports the amounts of resources used, it is also strongly influenced by economic impact. Tools used by Green Building Studio enable you to assess:

Energy and carbon results Water usage data Photovoltaic potential Daylighting results Design alternatives

The results in Green Building Studio are often reported in monetary terms that reflect the local costs of utilities.

Autodesk Ecotect Analysis

Ecotect Analysis is a software tool that evaluates the performance of your model based on climate and environmental factors. Ecotect Analysis can import gbXML files of your model and runs them against location-specific weather data. Tools used by Ecotect Analysis enable you to assess:

Whole building energy analyses Thermal performance Solar radiation Daylighting Shadows and reflections

Ecotect Analysis typically uses data visualization devices such as grids, shaded models, and color schemes to convey the results of the analyses performed. The results are often presented in a form that reflects scientific measures and quantities, rather than monetary measures.

Suggested Resources

Climate

National Solar Radiation Database rredc.nrel.gov/solar/old_data/nsrdb/tmy2/

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Weatherbase www.weatherbase.com

Western Regional Climate Center www.wrcc.dri.edu

Photovoltaic Panels

National Renewable Energy Laboratory nrel.gov

Solar Expert www.solarexpert.com/instroof5.html

National Renewable Energy Laboratory nrel.gov/rredc/pvwatts/

Thermal Properties of Building Materials

Colorado Energy www.coloradoenergy.org/procorner/stuff/r-values.htm

Sizes www.sizes.com/units/rvalue.htm

House-Energy www.house-energy.com/Insulation/R-value-insulation.htm

Energy and Power Consumption

US Department of Energy www.energysavers.gov/your_home/appliances/index.cfm/mytopic=10040

Energy Star www.energystar.gov/index.cfm?c=products.pr_find_es_products

Whole Building Design Guide www.wbdg.org/design/minimize_consumption.php

Water Use and Consumption

Environmental Protection Agency www.epa.gov/watersense/water_efficiency/what_you_can_do.html

Mother Earth News www.motherearthnews.com/Green-Homes/2006-08-01/Half-the-Water-Twice-the-Flush.aspx

uSwitch www.uswitch.com/water/how-much-water-use

LEED Rating System

United States Green Building Council www.usgbc.org

LEED Ratings www.usgbc.org/DisplayPage.aspx?CategoryID=19

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Power Score Card www.powerscorecard.org/reduce_energy.cfm

Autodesk Revit Architecture

Autodesk Revit Architecture 2011 User Assistance docs.autodesk.com/REVIT/2011/ENU/landing.html

Autodesk Revit Architecture Services & Support Center usa.autodesk.com/adsk/servlet/ps/index?siteID=123112&id=2956546&linkID=9243099

Autodesk Revit Architecture 2011 Tutorials usa.autodesk.com/adsk/servlet/item?siteID=123112&id=14844953&linkID=9243097

BIM Curriculum Materials and Support

Autodesk BIM for Architecture, Engineering, and Construction Management 2011 Curriculum students.autodesk.com/ama/orig/bim2010/start.htm

BIM Curriculum Support and Discussion http://www.bimtopia.com/bimcurriculum.html


Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design Lesson 1: Passive Design

Lesson 1: Passive Design Lesson Overview A good starting point for any green building design is to look at the passive features of the design:

The building placement and orientation on the site

The massing and shape of the building

The architectural features of the building, such as the placement of windows and shading features

These passive design features are inherent to the architectural design, materials choices, and configuration of the building. Decisions made when these features are designed determine the requirements for the active systemsincluding heating and cooling, power, and waterthat will be added to the building to meet the needs of its occupants.

A guiding principle is that passive features should be designed to maximize the positive benefits of the local climate and sunlightfor example, capturing sunlight as a heating and daylighting sourceand minimize the potentially negative effects, such as adding to the loads on the cooling system.

Some of the factors that should be considered as part of the passive design include:

Placement of the building on the site. What parts of the site are most desirable and why? What parts of the site should not be built upon?

Orientation of the building relative to the sun. The location of windows relative to the suns path can have significant impacts on the heating and cooling loads throughout the year.

The location of adjacent and surrounding buildings. Will other buildings cast shadows over certain parts of the site, rendering certain areas more or less desirable?

Access to buildings on the site. Consider where roads and entrances will be located and the impact on the users of the building.

Terrain and topography. Is the site evenly graded, or are some areas steeper with an uneven ground surface? Are there trees, vegetation, or natural design features on the site that should be preserved?

Views. Are there any particular views that occupants of the building will want to enjoy?

Building Orientation

The orientation of a building and its design features relative to the suns path can have a significant impact on the performance of the building and the comfort of its users.

As with many design decisions, choosing the best building orientation involves tradeoffs. If we orient a building to maximize the use of sunlight, we can improve daylighting and

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reduce the consumption of electricity for lighting. But the impact of increasing the solar radiation captured through the windows must also be considered. In cold weather months, this solar radiation can have positive benefits and help to heat the building. But in hot weather months, this solar radiation adds to the cooling loads and increases the power used by the cooling system.

Since the location of the sun in the sky changes throughout the year (and varies based on latitude), there is no single best answer. Analyses can be performed to determine the effects of a buildings orientation at various times through the year, and an overall optimum can be found that considers the positive and negative effects throughout the year.

Building Massing and Shape

The overall massing and shape of a building can also have significant effects on resource use. As we consider various options for enclosing the desired area or volume of built space, the relationship between the overall length, width, and height of the building determine the size and shape of the building envelope. For example:

Long, linear buildings provide lots of wall surfaces that can be used for windows to improve daylighting and reduce the need for artificial lighting. But these wall surfaces are also exposed to the temperature extremes of the external environment and will increase the heating and cooling loads.

Tall, skinny buildings also provide lots of wall surfaces relative to the area enclosed. Daylighting can be maximized, but these buildings often have the greatest heating and cooling requirements.

Compact buildings (with relatively similar lengths, widths, and heights) minimize the area of the building envelope relative to the volume enclosed. They tend to be very efficient from a heating and cooling perspective, but artificial lighting must be provided for interior spaces where daylighting is not sufficient.

Windows, Overhangs, and Shading

Optimizing the placement of windows is essential for good passive design. Well-placed windows provide daylighting (which helps reduce reliance of artificial lights that consume electricity) and an opportunity to capture solar radiation (which can help heat the building in cold weather months). But these benefits must be balanced with the effect of the additional cooling load created by the captured solar radiation during hot weather months.

To maximize the benefits of windows and minimize the negative effects, it is essential to design shading featuresfor example, roof overhangs, shutters or canopies, or brises soleilsthat will admit sun light during when it is beneficial, but block sunlight when it is not needed or desired.

Learning Objectives After completing this lesson, you will be able to:

Understand the importance of considering passive design features as a first step in the green design process.

Explore the effect of climate and solar orientation on building energy use.

Evaluate and estimate the impact of alternative massing strategies and building shapes on energy use.

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Understand the principles for designing and testing the effectiveness of roof overhangs and sun shading devices.

Suggested Exercises

Exercise 3.1.1: Finding the Optimum Building Orientation

In this exercise, you will learn how to:

Prepare BIM models for energy analysis.

Export model geometry using the gbXML file format.

Import gbXML model data into analysis tools, such as Autodesk Ecotect Analysis software and Autodesk Green Building Studio web service.

Use the Ecotect Analysis weather tool to find the optimum building orientation based on solar effects.

Use Green Building Studio design alternatives to determine the optimum orientation based on energy use.

Video Tutorial

Unit3_Lesson1_Tutorial1.mp4

Student Exercise

Unit3_Lesson1_Exercise1_Start.rvt

Find the optimum building orientation for this BIM model of a typical classroom unit using the Autodesk Ecotect Analysis weather tool. For this analysis, assume the school will be located in Detroit, Michigan.

Use Green Building Studio to determine the optimum orientation for the same classroom building and location to minimize the total annual energy cost. Create several design alternatives to evaluate the impact of rotating the BIM model by 15-degree increments.

Repeat these two analyses to find the optimum orientation recommended by each tool if the classroom is located in Phoenix, Arizona.

Figure 3.1.1. Weather tool showing the optimum orientation of a structure

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Figure 3.1.2. Using design alternatives in Green Building Studio to evaluate the total annual energy cost for different building orientations

Exercise 3.1.2: Comparing Massing and Shape Alternatives


Use simple BIM models to evaluate the energy use of different building massing and shape alternatives.

Use Green Building Studio to estimate the total annual energy use for each alternative.

Explore the impacts of different massing strategies on fuel use versus electricity use.

Video Tutorial


Student Exercise


Use Green Building Studio to analyze a third massing and shape alternative with the same floor area and number of classrooms configured as a two-story building. Compare the total annual energy cost as well as the fuel use and electricity use to the two alternatives explored in the tutorial. For this analysis, assume the school will be located in Detroit, Michigan.

Repeat the analysis of all three alternatives to evaluate the fuel use and electricity use tradeoffs if the school is located in Phoenix, Arizona.

Figure 3.1.3. Comparison of two BIM models with similar area but different shapes

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Figure 3.1.4. Energy use comparison in Green Building Studio for two building shape alternatives

Exercise 3.1.3: Designing Architectural Shading Features


Use Autodesk Revit software to evaluate the impact of sun and shadows on a building design.

Design and evaluate architectural features to optimize the use of sunlight throughout the year.

Estimate potential energy savings of proposed design features using Green Building Studio.

Video Tutorial


Student Exercise


For the given BIM model of a typical classroom layout, explore roof overhang and shading design options to optimize the use of sunlight throughout the yearallowing sunlight to warm the room during the winter, but blocking the sunlight during the warm summer months. For this analysis, assume the classroom is located in Detroit, Michigan.

Export your proposed new design as a gbXML file for analysis in Green Building Studio. Analyze the energy used by your new design and compare the results to the estimate for the earlier version of building (analyzed in exercise 3.1.1.).

Figure 3.1.5. Using shadows to evaluate shading design options

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Figure 3.1.6. Typical classroom unit with sunpath and shadows displayed

Assessment

Building Orientation

What measures does Ecotect Analysis evaluate to determine the optimum building orientation?

Does Green Building Studio consider the same measures?

Why does the optimum building orientation change based on the project location and local climate conditions?

Building Mass and Shape

How does changing the building shape and massing affect the estimate of total energy used and the distribution between fuel and electricity consumed?

Does changing the project location affect the best building shape?

Window Placement, Roof Overhangs, and Shading Features

How would your strategy for placing windows and designing shading features change based on local climate conditions?

What types of architectural shading features can be used to control sunlight?

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Key Terms The following key terms were used in this lesson:

Key Term Definition

Passive Design The technique of placing, orienting, and massing a building to optimize the use of the sun and climate to provide natural lighting, heating, and ventilation.

Optimum Building Orientation

The orientation (rotation relative to north) that maximizes the desired effect:

In Ecotect Analysis, the orientation that best balances the heat captured from solar radiation during colder months of the year with the additional cooling loads created during hotter months.

In Green Building Studio, the orientation that provides the lowest total annual energy cost (considering the cost of fuel for heating and electricity for cooling).

Building Massing The overall shape of a building, considering the length, width, and height. These factors determine the amount of space enclosed by the building and the surface area of the building envelope.

Shading Device An architectural, passive, or natural design feature used to block direct sunlight.


Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design Lesson 2: Material Properties and Energy Impact

Lesson 2: Material Properties and Energy Impact Lesson Overview In this lesson, you explore the impact of a buildings material properties on energy consumption. Choosing materials that minimize the energy consumed is an essential step in green building design.

You will learn about two key properties of building materialsthe R-value and the U-valueand explore how the choices they specify for the walls, roofs, and windows that comprise the building envelope affect the predicted annual energy costs for operating the building.


A building materials ability to resist the transfer of heat (or insulate) is often described through a single numberthe R-value.

The R-value is a measure of thermal resistance. Materials or assemblies with higher R-values are better insulators and help to moderate the effect of changes in outside temperature.

R-values are computed as the ratio of the temperature difference across an insulator to the heat that flows through that material, and the values for most typical building materials are readily available in reference books and online tables.

R-values are often given per unit of material thickness. So if a material is described as having an R-value of 1.0 per inch (25 mm), and a wall made solely from this material is 5-inches thick (0.13 m), the R-value for that wall would be 5.0 (1.0 per inch x 5 inches). More often, R-values are defined for entire wall assemblies.

U-value is the name of another property that is used to describe the thermal performance of building materials that are more conductive (less resistive) to transferring heat, such as windows and skylights.

While the R-value measures a materials resistance to transfer heat, the U-value does the inverseit describes a materials ability to transfer heat (U-value = 1 / R-value).

Materials or assemblies with higher U-values are better conductors. When comparing U-values for different window or wall types, lower numbers indicate better insulators that transfer less heat per unit of thickness.

Thermal Transfer

We can estimate the amount of heat that will be transferred between the interior and exterior of a building by considering:

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The thermal characteristics of each of the surfaces and assemblies that make up the building envelope.

The temperature differences between the interior and exterior of the building for the project location at different times of the day and throughout the year.

The range of temperatures that occupants of the building will consider to be comfortable during the times that it is being used.

Using this estimate, we can compute the amount of energy that will need to be consumed to heat and cool the building and the associated total energy cost.

Thermal Comfort

While energy efficiency is an important green design goal, it is important to balance this with the comfort of the occupants and users of the building. If a buildings users perceive the environment as too hot or too cold, they will be unhappy and unsatisfied with the design.

The issue of thermal comfort is complexdepending on a number of factors that all impact the perception of the usersand subjective. No two humans are exactly alike in their preferences. Some of the factors that affect the perception of comfort include:

Environmental factorsfor example, air temperature, radiant temperature, air velocity, and humidity

Personal factorsfor example, clothing worn and personal metabolism

Analysis tools such as Autodesk Ecotect Analysis softwares weather tool provide calculators that help assess the environmental factors for a given design and location and explore the ways that changing one affects the other. These tools, however, do not take personal factors into consideration.

Many different measures can be used to describe thermal comfort, calculating the thermal stresses on users of a space and translating those stresses into a number. The measures available in Ecotect Analysis include:

Predicted mean vote (PMV)a single digit number that estimates the average rating that would be given if a large group of people were asked about the comfort of a space. It ranges from +3 (for hot) to 0 (for neutral) to -3 (for cold).

Predicted percentage dissatisfied (PPD)a predicted percentage of people who would be dissatisfied with the comfort. As PMV increase or decreases (indicating that most people are feeling too hot or too cold), PPD also increases. Unlike PMV, which estimates the average rating given by a large group of people, PPD indicates the range of the individual responses.

Using PMV and PPD, we can quickly evaluate the impact of design decisions and get simple measures that consider the combined effect of many different thermal comfort factors. Although these measure are useful for evaluating the overall comfort of a space, other local factors that affect human comfort should also be considered, including:

Radiant temperature and vertical air temperature differences

Floor surface temperature

Cyclic variations in temperature

Drafts

Factors such as the heat or cold radiated through a window or the glare created by direct sunlight can make spaces uncomfortable or unacceptable.

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Understand the importance of considering materials properties as part of a green design process.

Describe how the thermal properties of the building materials and assemblies are quantified and reported.

Specify building materials and their thermal properties for elements in a BIM model.

Evaluate the energy use impact of building material alternatives.

Understand how thermal comfort settings affect energy use.

Suggested Exercises

Exercise 3.2.1: Evaluating the Impact of Material Thermal Properties


Specify building materials for wall and roof surfaces in Autodesk Green Building Studio software as a service (SaaS).

Create design alternatives to evaluate the energy use impact of different wall types.

Analyze and compare building materials choices that affect estimated energy costs.

Video Tutorial


Student Exercise


Using the classroom unit model analyzed in the tutorial, create design alternatives to explore the energy use impacts of using windows with different U-values.

Create additional design alternatives to explore the impact of using roof assemblies with different R-values.

Figure 3.2.1. Creating design alternatives to compare potential wall assemblies

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Analyze the estimates for the different wall, window, and roof alternatives. Then create design alternatives to evaluate the differences between systems combining the worst-performing the best-performing alternatives.

Exercise 3.2.2: Designing for Thermal Comfort


Define thermal zones, and specify the number of occupants, time of use, and heating and cooling system properties.

Use the Ecotect Analysis data grid to analyze the thermal comfort of regions within a space.

Estimate the energy resources required to maintain a rooms temperature within the comfort range.

Analyze and comparing the impacts of changing building material properties.

Assess the energy use impact of changing the limits of the comfort range.

Video Tutorial


Student Exercise


Explore the effect of specifying different window materials on the thermal comfort and resource consumption analyses. Compare these results to the baseline casethe initial materials choices in the Ecotect Analysis model.

Perform similar analyses to test the impact of specifying different roof materials. Compare these results to the baseline case.

Investigate the effects of changing the limits of the comfort range specified for the thermal zone. Raise the upper limit of the comfort range (allowing the zone to become warmer before cooling begins). Then run the resource usage analysis and compare the results.

Perform a similar analysis by decreasing the lower limit of the comfort range (allowing the zone to become colder before heating begins) and compare the results.

Figure 3.2.2. Analyzing thermal comfort in Ecotect Analysis

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Figure 3.2.3. Daily energy use (measured in pounds of CO2) due to heating and cooling to maintain temperatures within the comfort range

Assessment


How is the R-value computed for a wall composed of many layers?

If a layer of a wall assembly is made of two materials (for example, the core layer of many wood-framed walls includes wooden studs at 16 inches (0.40 m) on center and insulation between the studs), how is the R-value determined?

Does the location of the insulating materials affect the overall thermal performance of a wall or roof assembly?

How does the ratio of window area to wall area in the building envelope affect the energy consumed? As the percentage of window area increases, what typically happens to the energy consumed?

What is the relationship between changes in R-values (or U-values) and the energy consumption? Is it linear?

Can the results of analyzing a single classroom unit be extrapolated to estimate values for an entire school campus? Why or why not?

Thermal Comfort

How does the number of occupants, their activity level, and the time of use affect the heating and cooling required in a thermal zone?

Why does changing the upper or lower limit of the thermal comfort range have such a big impact on energy consumption? What determines how much you can raise or lower the limits?

How can the Ecotect Analysis thermal analysis be used to help specify the type and size of a heating and cooling system?

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Key Term Definition

R-value A measure of thermal resistance, or insulation. Larger R-values provide greater thermal resistance. In the United States, this measure is often used to describe insulative properties of solid assemblies, such as walls and roofs.

U-value The inverse of the R-value, the U-value measures thermal conductancehow much heat transfers through a material or assembly. In the United States, U-values are typically used to describe the thermal properties of windows and skylights. Around the world, U-values are also used to describe the thermal properties of solid assemblies (rather than R-values).

Thermal Zone A building area or group of rooms that will be treated as a single unit for heating and cooling analysis and design. Each thermal zone can have its own use properties (such as number of occupants, type of use, and time of use) and heating and cooling system.

Thermal Comfort Range

The range of temperatures that is considered acceptable for users of a space. When the temperature dips below the bottom of the range, heating devices are used to warm the space. When the temperature climbs above the top of the range, cooling devices are used to bring the temperature down.

Predicted Mean Vote (PMV)

A measure of thermal comfort that predicts what a large group of people would say about the temperatures being experienced within a space. It is typically measured on a scale from +3 (people feel hot) to -3 (people feel cold).

Predicted Percent Dissatisfied (PPD)

A measure of thermal comfort that predicts the percentage of people in a space that would be dissatisfied with the temperature they are feeling in that environment.


Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design Lesson 3: Water Use and Collection

Lesson 3: Water Use and Collection Lesson Overview In this lesson, you learn how to estimate the amount of water a buildings users and fixtures will consume and the percentage of this water demand that can be met sustainably by collecting rainwater.

Using a school campus composed of classroom units designed in the previous lessons as an example, you use the tools in Autodesk Green Building Studio software to estimate the water demand by considering the usage patterns and the fixture efficiency.

Next, they explore the potential for using an example of a net-zero measurerainwater harvestingto collect water to offset the water consumed by the users and fixtures.

Finally, student evaluate the potential for earning LEED points for by reducing water consumption through improved fixture efficiency as well as net-zero measures and recommend a strategy that balances these various design options.

Estimating the Water Demand Baseline

We can use the tools in Green Building Studio to estimate the total water demand created by the usage patterns and performance characteristics of the fixtures in our building model. We can start by considering the water used by each of the plumbing fixtures, then tabulate the data to estimate the total water demand.

The water used by each of the plumbing fixtures depends on several factors:

The flow characteristics of the fixturethe amount of water consumed by each use.

The usage patternthe estimated number of uses based on the number of building occupants, the building area provided, and the building type (for example, office versus school). Weekday usage is often quite different than weekend usage, especially for buildings that are used primarily on weekdays (such as schools).

Plumbing Fixture Efficiency

Most plumbing fixture manufacturers have introduced high-performance, low-flow versions of their products that allow you to create more efficient, sustainable designs. So as you place plumbing components in your model, you can consider and specify the types of fixtures to be used:

Standard fixtures that meet the minimum requirements specified by the applicable building codes

High-performance, low-flow fixtures that exceed the minimum requirements and reduce water use.

While high-performance fixtures may be more expensive to purchase, the additional investment is typically recovered quickly through their improved efficiency.

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Offsetting Water Use Through Net-Zero Measures

After reducing the estimated water use of a building through improved efficiency (for example, using high-performance fixtures), we can further reduce the water that will be needed from local utilities by finding ways to collect or reuse water on-site.

An effective strategy for locations and climates with significant rainfall is to collect and use rainwater to meet a part of the demand. Rainwater is often:

Collected on roof surfaces

Diverted to filtration systems and storage tanks

Pumped to supply the water used by some plumbing fixtures

Other net-zero strategies to consider include:

Use greywater systems to recycle water that can be used to flush sanitary fixtures or irrigate the landscaping.

Plant native vegetation that does not require irrigation.

Install waterless fixtures.

Many design teams set a design goal of meeting a specific percentage of a buildings estimated water demand through renewable sources, such as rainwater collection. Using the results of iterative analyses, design teams can decide on the optimal amount of rainwater collection area and compare the effects of various alternatives to meet their design goals.


Understand the importance of considering water use and innovative water reuse features as part of the green design process.

Estimate the water demand created by typical plumbing fixtures.

Explore the effect of using high-performance, low-flow fixtures on reducing water use.

Investigate the impact of using innovating water reuse and net-zero strategies for offsetting and reducing water demand on utilities.

Understand the LEED credits available for incorporating water efficiency measures in designs.

Suggested Exercises

Exercise 3.3.1: Estimating a Demand Baseline and Improving Efficiency


Use Green Building Studio to estimate the plumbing fixture requirements and water use based on building size and type.

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Adjust the fixture estimates to match the actual numbers placed in the BIM model.

Evaluate the water use impact of specifying high-efficiency plumbing fixtures.

Determine the LEED points available for different levels of water use reduction.

Video Tutorial


Student Exercise


Explore the impact of improving the efficiency of the plumbing fixtures specified on reducing water use.

Determine which plumbing fixtures should be changed to reduce indoor water use by 20 percent and earn 1 LEED point.

Investigate whether it is possible to reduce indoor water use by 30 percent (and earn another LEED point) by the efficiency of additional fixtures.

Figure 3.3.2. Indoor plumbing fixture summary in Green Building Studio

Figure 3.3.1. Specifying plumbing fixtures in restrooms

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Exercise 3.3.2: Offsetting Water Use Through Net-Zero Measures


Use Green Building Studio to explore the impact of net-zero measures that use innovative strategies to reduce dependence on water from utilities.

Estimate the water use reductions available through greywater reclamation.

Explore the potential reduction available through rainwater harvesting.

Determine the LEED points available by using these net-zero measures.

Video Tutorial


Student Exercise


Evaluate the feasibility of using rainwater harvesting to further reduce water consumption and maximize LEED water efficiency points.

Create an Autodesk Revit schedule to tabulate the total roof area available on the school campus.

Use Green Building Studio to determine the rainwater harvesting area required to collect enough water to reduce water consumption by 50 percent and earn one LEED point for Innovative Wastewater Technologies.

Continue working with Green Building Studio to determine the rainwater harvesting area required to reduce water consumption by 100 percent and earn a second LEED point for exemplary performance in Innovative Wastewater Technologies.

Determine which roof surfaces in the BIM model are the best candidates for rainwater collection to provide the needed rainwater harvesting area.

Figure 3.3.3. Specifying net-zero measures in Green Building Studio

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Figure 3.3.4. Summary of LEED Water Efficiency Credits in Green Building Studio

Assessment

Improving Plumbing Fixture Efficiency

What are the advantages and disadvantages of using high-efficiency plumbing fixtures? Are they more costly to purchase? To install?

What high-performance fixture options are available for:

o Toilets? o Urinals? o Showers? o Lavatory Sinks?

How can automatic sensors (for example, on lavatory sink faucets) be used to reduce water use?

Net-Zero Measures

What types of plumbing fixtures produce greywater?

What applications can greywater be used for?

What changes are required to plumbing systems to collect and use greywater?

What other net-zero sources of water (besides rainwater collection) can be used in climates where rainwater is not plentiful?

If the roof surface available is not sufficient to meet the rainwater harvesting area required, what other strategies can be used for collecting rainwater?

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Key Term Definition

Demand Baseline The estimated water usage when using fixtures that meet the standard building code minimal requirements.

Net-zero Measures Innovative design strategies that reduce the amount of water that must be supplied by local utilities. These measures can include collecting water from on-site sources as well as designing features and specifying systems that do not require off-site water.

Greywater Recyclable water collected from sinks, showers, washing machines, and fixtures that do not introduce any sanitary waste. Greywater is typically used for irrigation as well as flushing toilets and urinals.

Rainwater Harvesting Collecting, storing, and using the rainwater that naturally falls on a building or site. Rainwater harvesting is an example of a net-zero measure, using water from an on-site source (that would otherwise be wasted) to reduce the water consumed from local utilities.


Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design Lesson 4: Power Use and Generation

Lesson 4: Power Use and Generation Lesson Overview In this lesson, you learn how to evaluate the amount of energy used in a building and the amount of renewable power that can be generated on-site using photovoltaic (PV) panels on its roof (or in other locations on-site).

Using the school campus from the previous lesson as an example, you use the tools in Autodesk Green Building Studio software to estimate the energy needed to supply the electrical demands of the lighting fixtures, appliances, and other building equipment.

Then they explore the impact of reducing electrical demand by improving the efficiency of lighting fixtures and mechanical equipment as well as using controls to reduce waste.

Using this estimate of the energy demand as a target, they will then explore ways to determine the total area of PV panels required to meet all or a portion of that demand, focusing on payback analysis and the economic tradeoffs.

Estimating the Electrical Demand Baseline

We can use the tools in Green Building Studio to estimate the total electrical demand created by the usage patterns and performance characteristics of the electrical lights, appliances, and equipment in our building model. We can specify the:

Lighting power densitya measure of the amount of power used to provide lighting per square foot of a building that provides a convenient way to describe the overall efficiency of the lighting system (before the actual lighting fixtures are specified).

Controlsautomated timers and sensors used to reduce unnecessary power consumption by turning off lights when sufficient daylighting is available or when a room is not occupied.

HVAC systemthe type of heating, ventilating, and air-conditioning system that will be used and its efficiency.

While these three measures do not provide a completely accurate model of the power use in the design, they do reflect the characteristics of the major power demands and are sufficient for calculating a quick estimate of the power use for our building type and square footage.

Improving Efficiency

You can explore the effects of changing the lighting power density, the control systems installed, and the characteristics of the HVAC system to quickly assess the potential energy use impacts of using:

High-efficiency lighting fixtures, such as compact fluorescent lights (CFLs) and LED lights.

Automated timers, occupancy sensors, and daylighting sensors.

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Alternate heating, ventilating, and cooling systems with varying efficiencies.

Using high-efficiency fixtures and controls typically has a positive effect of reducing electrical consumption at a low cost. While the fixtures and controls may be more expensive to purchase, the additional investment is typically recovered quickly through their improved efficiency.

The effects of changing the HVAC system are subtler and must be considered carefully. Changing to systems that use a different mix of electrical power and fuel can bring economic savings (if, for example, fuel is less expensive than electricity) but actually have negative environmental effects (by creating a bigger carbon footprint).

Offsetting Power Use Through Net-Zero Measures

Photovoltaic (PV) panels are an excellent source for generating renewable electrical power.

The roof surfaces of a building often provide the best unobstructed views of the sun, so photovoltaic systems are typically placed there. Factors to consider when designing roofs for solar use include:

Roof areagreater roof area generally provides more potential for placing photovoltaic panels. But each roof surface must be evaluated independently, because the actual power that can be generated will depend upon the direction and slope of the panels.

Roof slope or panel tiltpanels are typically places to minimize the incident angle with the sun and maximize the current generated. The optimum slope or tilt depends on the project locations latitude.

Orientationpanels typically placed to face the direction that maximizes the amount of current that can be generated.

The amount of power that can be generated by PV panels also depends on a number of other factors:

Insolationa measure of the solar energy available at specific geographic locations in the world.

Panel efficiencya rating that describes the percentage of the available solar energy that can be converted into useful power by a specific type of PV panel.

The power-generating potential of PV panels can be calculated in several different ways. The photovoltaic analysis tools in Green Building Studios perform these calculations and assess the photovoltaic potential of every external surface of the building model and report that potential, so you can choose which surfaces are the best candidates for panel installation.

Payback Period

Often it is not feasible or advisabledue to space and budgetary limitationsto supply 100 percent of the estimated energy demand by generating power through renewal means, such as PV panels.

If the cost of installing panels on a surface exceeds the expected values of the savings that will be realized by reducing power consumption, then it does not make economic sense to do so. To assist with evaluating which surfaces should be used, Green Building Studios calculates a payback periodthe period of time required to recover the initial investment through the annual savings that will be realized through the operating life of the systemfor each potential surface. You can enter a desired payback period based on

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your economic objectives (for example, 50 years), and the tool will highlight the surfaces that can be used to meet this objective.

Other noneconomic factors can also enter into design decisions about which surfaces to use. For example, the design team may want to achieve a specific level of power reduction to earn LEED points. Or one of the buildings design requirements may be net-zero energythat is, the building can provide all of its own power requirements and essentially be off the grid. In these cases, design teams can override the recommendations made based on the payback period and analyze the power-generating potential of all surfaces, regardless of cost.


Understand the importance of considering power use and innovative power-generation features as part of the green design process.

Estimate the electrical demand created by typical lighting fixtures and other building loads.

Explore the effect of using high-efficiency lighting fixtures and controls on reducing power use.

Investigate the impact of using photovoltaic panels to generate power and reduce demand on utilities.

Understand the LEED credits available for incorporating power efficiency and alternative power-generation measures in designs.

Suggested Exercises

Exercise 3.4.1: Estimating a Demand Baseline and Improving Efficiency


Use Green Building Studio to estimate annual electrical use based on building size and type.

Evaluate the electrical end use impact of specifying high-efficiency lighting fixtures, controls, and HVAC systems.

Use design alternatives to compare strategies for reducing electrical use.

Determine the LEED points available for different levels of power use reduction.

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Video Tutorial


Student Exercise


Create design alternatives in Green Building Studio to explore the effects of different strategies for reducing electric use.

Compare the potential reduction available through specifying different lighting power densities.

Explore the potential reduction available through different lighting controls.

Investigate the potential reduction achievable using different HVAC systems choices.

Exercise 3.4.2: Offsetting Power Use Through Net-Zero Measures


Evaluate the photovoltaic potential of building surfaces by considering the solar energy available at the project location as well as the orientation and tilt of each of the surfaces.

Determine which surfaces of a building are worthwhile candidates for photovoltaic panels by considering the payback period required to offset the cost of installing the panels.

Calculate the LEED points available by using photovoltaic panels to generate power on-site and reduce reliance on utilities.

Figure 3.4.1. Exploring annual electric and fuel use estimates in Green Building Studio

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Video Tutorial


Student Exercise


Using the data presented in Figure 3.4.3 and electrical end-use computed in Green Building Studio, determine the amount of baseline energy that must be obtained from renewable sources (such as photovoltaic generation) to obtain 4 LEED points.

Use the photovoltaic analysis tools in Green Building Studio to explore the effect of changing the desired payback period on the number of surfaces and total area recommended for photovoltaic panels.

Determine the length of the payback period that will be required to recover the cost of installing the area of photovoltaic panels required to provide enough on-site renewable energy to earn 4 LEED points.

Determine the length of the payback required to recover the cost of installing enough photovoltaic panels to earn 7 LEED points.

Create a new run in Green Building Studio to explore how these answers change if the project is located in Phoenix, Arizona (a very sunny climate), rather than Detroit, Michigan.

Figure 3.4.3. LEED points for providing on-site renewable energy

Assessment

Improving Power Efficiency

What strategies can be used to reduce the power density of a building? How do lighting controls and sensors work to reduce energy demand?

Figure 3.4.2. Example of a photovoltaic potential

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How can you encourage a buildings users to become active participants in reducing power demand?

Photovoltaic Generation

Why is payback used as a driving consideration in determining how much photovoltaic panel area to provide? Why not cover the entire available area with panels?

What are the primary factors that determine the payback period for installing photovoltaic panels? How can changes in the values assumed affect the results of our payback analysis?


Key Term Definition

Lighting Power Density A measure of the amount of power used to provide lighting per square foot of a building. This provides a convenient way to describe the overall efficiency of the lighting system (which can be used before the actual lighting fixtures are specified).

Controls Switches, timers, and sensors used to turn lights and appliances on and off. Automated controls (as opposed to manual switches) are used to reduce unnecessary power consumption by turning off lights when sufficient daylighting is available or when a room is not occupied.

Insolation A measure of the solar energy available at specific geographic locations in the world.

Photovoltaic Potential An assessment of the energy saving potential of photovoltaic panels that considers the energy that can be produced by panels versus the cost of installing them.

In Green Building Studio, it is expressed as the annual energy savings predicted from installing photovoltaic panels whose cost can be recovered within a maximum payback period.

Payback Period The number of years required to recover the initial investment in a photovoltaic system through the annual savings that will be realized through the operating life of the system.


Autodesk BIM Curriculum 2011 Student Workbook Unit 3: Green Building Design Lesson 5: Daylighting

Lesson 5: Daylighting Daylighting is a measure of the amount of natural light from the sky or reflected off surfaces in the external environment that is experienced inside a space. It is typically captured through windows, skylights, and other glazed openings; daylighting strategies must be carefully designed to gain the maximum benefits of the illuminance available at the project location.

Using daylighting effectively is an important feature of sustainable design because natural lighting can help make the building less reliant on the electrical power typically consumed by artificial lighting, which can reduce the total building energy costs by as much as one-third. Good daylighting design can also help to create a visually stimulating and productive environment, which benefits all of the buildings occupants and users.

Benefits of Daylighting

Daylighting has the potential to significantly improve a buildings lifecycle cost, increase the productivity of occupants and users, and reduce the buildings operating costs and emissions:

Improved lifecycle costinstalling dimmable ballasts, fixtures and controls to adjust artificial lighting based on daylighting typically adds a small incremental one-time installation cost (estimated at $0.50 to $0.75 per square foot [$5.38 to $8.06 per square meter] of occupied space), but can result in an estimated annual savings of $0.05 to $0.20 per square foot [$0.56 to $2.15 per square meter] (measured in 1997 dollars). This brings a very significant savings over the lifecycle of the building.

Increased user productivityresearch results show that daylight enlivens a space, increases user satisfaction and visual comfort, and leads to improved performance and productivity.

Reduced emissionsusing daylight helps to reduce the use of electrical power for lighting and cooling, thereby reducing greenhouse gas production and slowing fossil fuel depletion.

Reduced operating costsartificial lighting typically accounts for 35 to 50 percent of the total electrical energy consumption in commercial buildings. It also generates waste heat, which adds to the loads on the buildings HVAC system. Reducing electric lighting through the use of daylighting strategies can directly reduce the energy needed to cool a building by an estimated 10 to 20 percent.

Daylighting Design Goals

Proper daylighting design requires careful balancing many considerations, including heat gain and loss, glare control, and variations in daylight availability. Successful daylighting designs typically consider:

Window sizing, placement, and spacing

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Glazing material selection

Shading devices to reduce glare and excessive contrast

Light reflecting devices and features to enhance light capture and bounce light to locations where needed

Color and reflectance of interior finishes

Location and design of interior partitions and potential light blockers

To qualify for LEED certification, a buildings design must also provide a minimum glazing factor of 2 percent in a minimum of 75 percent of all regularly occupied areas.

Recommended Daylighting Levels

The Illuminating Engineering Society of North America publishes an industry-standard method for determining recommended illuminance levels (expressed in units of footcandles, or fc) for various tasks. The amount of daylighting required in a room depends on the tasks being performed there. The following are some generally accepted lighting-level recommendations:

Task Recommended

Footcandles

High contrast (ink, soft lead) 50 - 75 - 100 Drafting

Low contrast (hard lead) 100 - 150 - 200

Simple 20 - 30 - 50

Moderate 50 - 75 - 100

Inspection

Difficult 100 - 150 - 200

Machine Work Medium, grinding, and so on 50 - 75 - 100

Materials Handling Picking, packing, wrapping, labeling 20 - 30 - 50

Lobby, corridor, waiting area 10 - 15 - 20

Toilets, restrooms 10 - 15 - 20

Other

Teller stations, ticket counters 50 - 75 - 100

General 20 - 30 - 50

Soft pencil (#2), pen, good copies, keyboards, > 8-point type 20 - 30 - 50

Reading

Hard pencil (#3), phone books, poor copies, < 8-point type 50 - 75 - 100

Schools Science laboratories 50 - 75 - 100

Inactive 5 - 7.5 - 10

Active, large items 10 - 15 - 20

Storage

Active, small items 20 - 30 - 50

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Daylighting Design Strategies

Design strategies that can be explored to improve daylighting include:

Increase the perimeter daylight zonesextend the perimeter footprint and wall area to maximize the potential for usable daylighting area.

Provide daylight penetrations high in a spacelocating windows high on a wall (for example, clerestory windows) or in the roof (for example, skylights) brings in light that can penetrate deeper into a space and reduces the likelihood of excessive brightness and glare.

Reflect daylight within a space to increase room brightnessusing properly designed light shelves, designers can improve the overall room brightness while decreasing excessive brightness at the window.

Slope ceilings to direct more light into a spacesloping ceilings away from the windows and glazing area helps increase the brightness of the ceiling and brings daylight further into the space.

Avoid direct sunlight and excessive brightness on critical visual tasksdirect sunlight and excessive brightness in the vicinity of critical visual tasks can create user discomfort and poor visibility.

Filter and soften daylightusing curtains, shades, louvers, natural vegetation or other light filtering devices reduces the harshness of direct light and helps to distribute it more evenly.

Effective daylighting design also depends on the orientation of the building surfaces being designed and the position of the sun. The appropriate combination of daylighting strategies typically varies based on the sunlighting experienced on each building face. For example, light shelves that are typically very effective on south elevations are often ineffective on the east or west elevations of buildings.


Understand measures of daylighting, such as daylight factors, daylighting levels, and overall light levels.

Analyze and estimate the daylighting levels provided in a design.

Add or remove design features in order to improve daylighting and assess their impact.

Understand the minimum requirements for daylighting levels that must be provided for LEED certification of a building.

Suggested Exercises

Exercise 3.5.1: Analyzing the Daylighting Provided in a Design


Use the Autodesk Ecotect Analysis grid to calculate the daylighting levels at various locations within a design.

Set daylighting analysis assumptions to create an accurate estimate.

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Compare different types of lighting level analyses and the information they provide.

Video Tutorial


Student Exercise


Use the Ecotect Analysis grid tool to perform an analysis to estimate the daylighting factors (as a percentage) provided at various locations on the balcony level of the library.

Repeat the analysis to estimate the daylighting level (in footcandles) provided at the balcony level.

Identify especially dark and bright locations to be improved through design measures in the next exercise.

Figure 3.5.2. Autodesk Ecotect Analysis grid showing daylighting values at loft level in school library

Figure 3.5.1. Autodesk Ecotect Analysis surface model of school library building

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Exercise 3.5.2: Adding Design Features to Improve Daylighting


Model architectural features to improve the daylighting conditions within a space.

Increase daylighting through window and skylight placement.

Decrease daylighting through shading.

Analyze the effectiveness of proposed design changes.

Video Tutorial


Student Exercise


Use Autodesk Revit Architecture software to add design features (for example, windows, skylights, and shading) to improve the daylighting on the second floor level of the library building.

Try to increase the daylighting in the southeast corner of the balcony to provide natural light sufficient for a reading or study area.

Try to reduce the daylighting levels in the southwest corner to minimize the glare on computer screens in a planned cluster area.

Export the revised model as a gbXML file and open it in Ecotect Analysis. Then repeat the daylighting analysis performed in the last exercise and compare the results to assess the effectiveness of your design changes.

Figure 3.5.3. View of the results of a daylighting analysis in Ecotect Analysis

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Figure 3.5.4. Analysis grid showing effect of new daylighting design improvements

Assessment

Analyzing the Daylighting Provided in a Design

Is it beneficial to have even daylighting across an entire room? When might darker or lighter areas be more advantages?

What is the essential difference between daylight factor and daylighting levels? How are they related?

What characteristics of a space, besides the total glazing area and window placement, have the biggest impact on daylighting levels?

Adding Design Features to Improve Daylighting

Are there times when daylighting should be reduced? What kind of design features can be used for these applications?

What types of interior design features can be used to disperse and reflect light?

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Key Term Definition

Sky Illuminance A measure of the skys brightness. Illuminance is the total amount of light coming from the sky based on a projects location and sky conditions. The sky illuminance is not affected by project orientation.

Design Sky Illuminance The sky illuminance level that is exceeded 85 percent of the time between the hours of 9 a.m. and 5 p.m. throughout the working year. This is a conservative design value for daylighting analysis.

Daylight Factor The amount of daylight at a location measured as a percentage of the design sky illuminance.

Daylighting Level The intensity of daylight at a location measured in footcandles. Appropriate levels are defined by the intended uses of each space.


Autodesk, Ecotect, Green Building Studio, and Revit, are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and/or other countries. All other brand names, product names, or trademarks belong to their respective holders. Autodesk reserves the right to alter product and services offerings, and specifications and pricing at any time without notice, and is not responsible for typographical or graphical errors that may appear in this document. 2010 Autodesk, Inc. All rights reserved.

Documents

Bim Unit-03 Student Workbook 2011 FINAL