For Quiz 3 and Final Exam

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1 For Quiz 3 and Final Exam Final Exam Times: Section 001(10:10am) Monday May 8 th 10:15am 12:15pm Section 002 (11:15am) Wednesday May 10 th 10:15am 12:15pm Urban Heat Islands (UHI) An Urban Heat Island (UHI) is created around a metropolitan area, where the central urban area s land cover (concrete, pavement, metal, etc.) absorb and retain more heat from the sun than those land covers of the surrounding countryside (grass, trees, dirt, etc.) 1

2 Normal distribution of solar radiation 2

3 The electromagnetic spectrum Solar radiation Ranges from long to short wave, but is largely shorter wave Includes visible light 3

4 Solar and earth radiation Solar radiation is (1) reflected By aerosols and gas molecules in the atmosphere back into space Aerosol Noun. Physical Chemistry. a system of colloidal particles dispersed in a gas; smoke or fog. By water and solid earth on the ground back into either the atmosphere or into space Albedo measures an object s reflectivity, expressed as a percentage of the radiation received by the object that is reflected Surface albedos vary considerably 4

5 Albedo (reflectivity) Solar radiation is (2) scattered By atmospheric aerosols and gas molecules to elsewhere in the atmosphere A greater concentration of larger aerosols results in more scattering Short wave radiation tends to scatter more Blue sky and an orange red sky both result from scattering of visible light radiation 5

6 Solar radiation is (3) absorbed By aerosols and gases in the atmosphere By water and solid objects on the ground Absorption results in the transfer of heat energy to the object with which the radiation comes into contact Urban Heat Islands (UHI) An Urban Heat Island (UHI) is created around a metropolitan area, where the central urban area s land cover (concrete, pavement, metal, etc.) absorb and retain more heat from the sun than those land covers of the surrounding countryside (grass, trees, dirt, etc.) 6

7 Normal distribution of solar radiation 7

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9 Albedo (reflectivity) 9

10 Urban Heat Islands (UHI) An Urban Heat Island (UHI) is created around a metropolitan area, where the central urban area s land cover (concrete, pavement, metal, etc.) absorb and retain more heat from the sun than those land covers of the surrounding countryside (grass, trees, dirt, etc.) UHI Mitigation Remember: Mitigation means, to lessen the severity of something By increasing vegetative cover and by using construction materials that have similar energy absorption properties as the natural world, we can reduce UHI There are four main strategies to UHI Mitigation: Increasing tree and vegetative cover Installing green roofs Installing cool mainly reflective roofs, and Using cool pavement material 10

11 (UHI) Mitigation Strategies Vegetative cover Trees and other plants help cool the environment, making vegetation a simple and effective way to reduce urban heat islands Trees and vegetation lower surface and air temperatures by providing shade Shaded surfaces, for example, may be F cooler than the peak temperatures of unshaded materials Trees and vegetation are most useful as a mitigation strategy when planted in strategic locations around buildings or to shade pavement in parking lots and on streets Additional Benefits of increasing vegetative cover in urban environments: Reduced energy use: Trees and vegetation that directly shade buildings decrease demand for air conditioning Improved air quality and lower greenhouse gas emissions: By reducing energy demand, trees and vegetation decrease the production of associated air pollution and greenhouse gas emissions Enhanced stormwater management and water quality: Vegetation reduces runoff and improves water quality by absorbing and filtering rainwater Reduced pavement maintenance: Tree shade can slow deterioration of street pavement, decreasing the amount of maintenance needed Improved quality of life: Trees and vegetation provide aesthetic value, habitat for many species, and can reduce noise (UHI) Mitigation Strategies Green Roofs A green roof, or rooftop garden, is a vegetative layer grown on a rooftop Green roofs provide shade and remove heat from the air reducing temperatures of the roof surface and the surrounding air On hot summer days, the surface temperature of a green roof can be cooler than the air temperature, whereas the surface of a conventional rooftop can be up to 90 F (50 C) warmer Additional Benefits of using Green Roofs Reduced energy use: Green roofs absorb heat and insulate buildings, reducing energy needed for cooling and heating Reduced air pollution and greenhouse gas emissions: By lowering air conditioning demand, green roofs can decrease the production of associated air pollution and greenhouse gas emissions. Vegetation can also remove air pollutants. Improved human health and comfort: Green roofs, by reducing heat transfer through the building roof, can improve indoor comfort and lower heat stress associated with heat waves Enhanced stormwater management and water quality: Green roofs can reduce and slow stormwater runoff in the urban environment; they also filter pollutants from rainfall Improved quality of life: Green roofs can provide aesthetic value and habitat for many species. 11

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13 (UHI) Mitigation Strategies Cool Roofs A high solar reflectance or albedo is the most important characteristic of a cool roof as it helps to reflect sunlight and heat away from a building, reducing roof temperatures A high thermal emittance also plays a role, particularly in climates that are warm and sunny Together, these properties help roofs to absorb less heat and stay up to F (28 33 C) cooler than conventional materials during peak summer weather Additional Benefits of using Cool Roofs Reduced energy use: A cool roof transfers less heat to the building below, so the building stays cooler and uses less energy for air conditioning Reduced air pollution and greenhouse gas emissions: By lowering energy use, cool roofs decrease the production of associated air pollution and greenhouse gas emissions Improved human health and comfort: Cool roofs can reduce air temperatures inside buildings with and without air conditioning, helping to prevent heat related illnesses and deaths 13

14 Urban Heat Islands (UHI) Impact example As shown in this example from New Orleans, electrical load can increase steadily once temperatures begin to exceed about F (20 25 C) This is an effect in cities that rely on air conditioning 14

15 (UHI) Mitigation Strategies Cool Pavements Cool pavements currently refers to paving materials that reflect more solar energy, enhance water evaporation, or have been otherwise modified to remain cooler than conventional pavements Cool pavements can be created with existing paving technologies (such as asphalt and concrete) as well as newer approaches such as the use of coatings or grass paving Additional Benefits of using Cool Pavements: Reduced stormwater runoff and improved water quality: Permeable pavements can allow stormwater to soak into the pavement and soil, reducing runoff and filtering pollutants Lower tire noise: The open pores of permeable pavements can reduce tire noise by two to eight decibels and keep noise levels below 75 decibels Enhanced safety: Permeable roadway pavements can improve safety by reducing water spray from moving vehicles and increasing traction through better water drainage Improved local comfort: Cool pavements in parking lots or other areas where people congregate or children play can provide a more comfortable environment 15

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18 Dallas Texas, Trinity River Greenway (Conceptualization) Columbus Ohio, Scoito Mile River Front Park (Conceptualization) 18

19 Qian'an Sanlihe Greenway Qian'an City, Hebei Province, China Embedded Energy Energy consumption in buildings occurs in five (5) phases: 1. The energy used in the manufacturing of the building materials This is called Embedded energy 2. The energy used to transport materials to building sites This is called Grey energy 3. The energy used in the actual construction of the building This is called Induced energy 4. The energy consumed in running the building once occupied This is called Operational energy 5. The energy consumed in the demolition process Concrete, aluminum and steel are among the materials with the highest Embedded energy content This is called Demolition energy Embedded Energy consumption can be reduced by using different building materials 19

20 Green Ranking and Rating Systems 1. Energy Star 2. LEED (Leadership in Energy & Environmental Design) 3. HERS (Home Energy Rating System) ENERGY Star sponsored by the US Govt. ENERGY STAR certified new homes are designed and built to standards well above most other homes on the market today They deliver energy efficiency savings of up to 30 percent when compared to typical new homes Requirements set by the U.S. Environmental Protection Agency (EPA) A new home that has earned the ENERGY STAR label has undergone a process of inspections, testing, and verification to meet strict delivering better quality, better comfort, and better durability 20

21 About ENERGY Star The ENERGY STAR program was established by EPA in 1992, under the authority of the Clean Air Act Section 103(g). Section103(g) of the Clean Air Act directs the Administrator to "conduct a basic engineering research and technology program to develop, evaluate, and demonstrate non regulatory strategies and technologies for reducing air pollution." In 2005, Congress enacted the Energy Policy Act. Section 131 of the Act amends Section 324 (42 USC 6294) of the Energy Policy and Conservation Act, and "established at the Department of Energy and the Environmental Protection Agency a voluntary program to identify and promote energy efficient products and buildings in order to reduce energy consumption, improve energy security, and reduce pollution through voluntary labeling of or other forms of communication about products and buildings that meet the highest energy efficiency standards." 21

22 LEED (Leadership in Energy & Environmental Design) sponsored by the U.S. Green Building Council (private sector) is a rating system that encourages innovative and established approaches to constructing the built environment LEED is a program that provides third party verification of green buildings Energy efficiency and environmental sensitivity are the defining attributes to a LEED certified homes LEED is a certification system for buildings and a professional credential that affirms your advanced knowledge in green building as well as expertise in a particular LEED rating system LEED Credentials (Professional) LEED Green Associate demonstrates a solid, current understanding of green building principles and practices LEED AP Building Design + Construction for professional with expertise in design and construction LEED AP Operations for professionals implementing sustainable practices through enhanced operations and maintenance LEED AP Interior Design for professionals in the design, construction and improvement of commercial interiors and tenant spaces that offer a healthy, sustainable and productive work environment LEED AP Homes for professionals involved in the design and construction of healthy, durable homes that use fewer resources and produce less waste LEED AP Neighborhood Development for professionals participating in the planning, design and development of sustainable, pedestrian friendly neighborhoods 22

23 LEED Rating Systems (Buildings) Rating systems are groups of requirements for projects that want to achieve LEED certification. Projects earn points to satisfy green building requirements Within each of the LEED credit categories, projects must satisfy prerequisites and earn points The number of points the project earns determines its level of LEED certification LEED Rating Systems (Buildings) Rating systems are groups of requirements for projects that want to achieve LEED certification. Additional LEED for Homes credit categories Projects earn points to satisfy green building requirements Within each of the LEED credit categories, projects must satisfy prerequisites and earn points Additional LEED for Homes credit categories The number of points the project earns determines its level of LEED certification Two Bonus Credit Categories 23

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25 Top 10 U.S. Cities Ranked By Total Number of LEED Projects as of 5/4/

26 Home Energy Rating System (HERS) Developed by the Residential Energy Services Network (RESNET) The HERS Index is the industry standard by which a home s energy efficiency is measured Government agencies that recognize the HERS Index Department of Energy (DOE), Department of Housing and Urban Development (HUD) and the Environmental Protection Agency (EPA) Home Energy Rating System (HERS) The HERS Calculations require us to think about energy in different conceptual ways, and requires us to identify what specific purposes we use energy for Legend: E=energy consumption, wh=water heating, la=lights and some appliances, PE=purchased energy (fraction) Legend: PE=purchased energy, E= energy 26

27 Home Energy Rating System (HERS) FILMS: The Making Room For Cities Paradigm The Compact Integrated and Connected Cities Paradigm 27

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30 The Contemporary Megacity 30

31 Developing cities and their host countries are growing in size and population in nearly all regions of the world, but most notably in Asia, then South America Real Estate firms develop the most up to date analysis of urban happenings around the globe This graphic shows the difference between global rural/urban populations and each areas contribution to global GDP Clearly most of the 54% of global GDP is originating from 23 megacities and the next tier (megacities inwaiting) of 577 middleweights as the firm calls them 31

32 Growing Emerging Market Cities Require Investment to Build Capacity The world s new urban consumers will have an impact far beyond sales of goods and services to be successful, cities will need to invest heavily in infrastructure. Three types of infrastructure has been identified as crucial: 1) Buildings/floor space By 2050, cities will need to construct floor space equivalent to 85 percent of all of today's existing urban residential and commercial stock. 2) Municipal water service Urban municipal water demand may rise by 80 billion cubic meters, equivalent to more than 20 times the water consumption of New York today and 40% above today s urban global level. 3) Container capacity of ports The capacity of ports to handle global container traffic needs to rise by more than 2.5 times from today s level to meet rising consumer demand for products across the globe. This graphic shows how there is no direct relationship between the growth in population and the growth in economies in megacities In most cases, populations are growing far more rapidly than the cities economies What problems can you see from this relationship in the near future? What does this mean for the USA? 32

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