Senior Design Project for UNO. Design of the International Studies Building: An Environmental Analysis

Transcription

1 Senior Design Project for UNO Design of the International Studies Building: An Environmental Analysis

2 Design Intent Implement Passive & Active design strategies in order to make the building: More Energy Efficient Use Less Water Provide Cleaner Indoor Air

3 Passive Strategies Let Nature do the work for you By conforming the building to its surrounding environment, and using the resources that are provided to the designer, a certain portion of the heating, cooling, ventilating, and lighting can be provided by the natural environment.

4 Active Strategies Using Mechanical Equipment to provide a building with its heating, cooling, ventilating, and lighting needs.

5 Energy Efficiency High rate of thermal resistance for the Building s Envelope (walls, floors, roof, doors, and windows) High rate of performance for the building s mechanical equipment.

6 Indoor Air Quality To make a healthier & cleaner environment for the occupants of the building.

7 End Goal of Design Intent To make a more energy efficient building To create a cleaner, healthier outdoor and indoor environment.

8 International Studies Building at UNO Located in New Orleans, which is subjected to intense summer heat and high relative humidity, and due to its location near the equator, receives a lot of solar radiation. And finally, the building layout, is such that the building is short, stocky and contains many partitions within the structure. Due to these factors, how do you decide which design strategy to use?

9 Passive Design Strategies The building requires the use of a lot less energy by implementing a few passive design strategies: 1. modern insulation 2. a green roof 3. reflective, exterior paint 4. Modern windows and doors 5. Water Vapor Retarder

10 Active Design Strategies Then the remaining active strategies can provide the building with the necessary heating, cooling, ventilating, and lighting. And not cause large energy deficiencies: 1. High Performing Heating and Cooling System 2. Indoor Air Heat Exchangers 3. Solar Photovoltaic Cells 4. Water Efficient Toilets & Sinks 5. High Efficiency Lighting

11 Design an Air-Tight, Thermally Resistant Building Envelope In order to understand how to construct a thermally resistant envelope, it is important to understand the mechanics of heat transfer.

12 3 Methods of Heat Transfer Convection is either the passage of cool air around an hot object, and the air will thus be heated and the object cooled or vice versa, the passage of hot air around a cool object, and the air will be cooled and the object heated. Conduction when there is a temperature difference between two objects, and they come into physical contact, heat is transmitted through the objects Radiation When light waves hit and penetrate an object, heat is transferred to the object.

13 Building Envelope Reflect Radiation Thermally resistant to conduction Limit the infiltration of hot air Limit the infiltration of hot, humid air.

14 Reflect Radiation Through the use of heat reflecting paint, (Thermoseal): Reflects over 80% of incident radiation Both the color and the properties of the material make it a good reflector of radiant energy. For instance, the color white typically absorbs only 30% of solar radiation, while black absorbs nearly 90%. Through the use of a green roof: the most effective energy reduction method being provision of shade to prevent the solar energy actually reaching the roof surface.

15 Thermally Resistant to Conduction By means of effectively insulating the building, heat is less able to transfer from the exterior of the wall to the interior of the wall. Extruded Polysterene is rigid foam board with an R Value of 5 per inch. It is also water resistance, (vapor retarder) so humid air will not be able to travel through the wall and latent heat (heat from moisture) to be transferred to the interior as well.

16 Thermally Resistant to Conduction Another way of effectively insulating the building is improving window quality Double-Glazed Clear Window U value =.49 VT =.57 Air Leakage =.37 cfm/ft

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19 Reducing Air Infiltration By means of insulation, joint sealants (caulking all potential areas for leakage), and the use of better windows and doors.

20 Reducing Humid Air Infiltration Waterproof Foam Insulation Also including a drainage plane installed just inside the exterior wall (tar paper) that will prevent moist air from flowing through the insulation. This causes both latent heat transfer to the interior, and it also causes mold formation in the interior of the wall.

21 Heat Gain Gains from many sources: Through Roof & Walls Through Glass From Outdoor Air From People From Lights From Equipment And From Latent Heat

22 Summer Condition in New Orleans Design Outdoor temperature around 91 degrees Solar Heat Gain Factor of 276 Btu/h*ft² for June 21 st at 12 noon, when the angle of incidence of the sun is nearly horizontal ** will explain this factor on next slide

23 Sol Air Temperature Sol Air Temp = [t + (α * I)/3] - 7 Sol Air Temp is the surface temperature of an object depending on the absorption rate of an object, and solar heat factor which is based from the angle of incidence of the sun. t = design outdoor air temperature α = absorption rate I = Solar Factor

24 Calculation of Heat Gain Through Roof & Walls Q = U * A * DETD Q = rate of heat gain U = the inverse of the total resistance for the entire assembly A = area of the assembly for which you are calculating the heat gain DETD = Design Equivalent Temperature Difference, which is based from the type of structure you are calculating, and the design outdoor temperature.

25 Calculation of U Value R Value U = 1/ R For instance, for the roof, U = 1/38.5 =.025 Inside Air Film.68 Gypsum Board.45 Expanded 5/in = 30 Polystrene(6 ) Steel Deck.05 Concrete Slab.2 Green Roof(6 ) 1.2/in =7.2 Total 38.5

26 Calculation of Heat Gain Through Roof and Walls So, once you have the U-value for the entire assembly, go back to the equation Q= U*A*DETD In this example, U = 1/R =.025 A = 132*140 = 18400ft² DETD (from the manual) = 35 So, Q =.9415 Btu/h*ft²

27 Heat Gain Through Glass Q= A * DCLF (Cooling Load Factor) Values for DCLF are acquired in a manual. The value is dependent on the type of glass, and the difference between indoor and outdoor temperature.

28 Gains From Outdoor Air To get gains from outdoor air, you need to break up the heat gain into two categories: 1. Gains from infiltration 2. Gains from ventilation

29 Gains From Outdoor Air Gains from infiltration are computed: Q=A*infiltration factor A=exposed area of leak Infiltration factor: standard value found in table Gains from ventilation are computed: Q=V*ventilation factor V= volume of incoming air Ventilation factor = standard value found in table

30 Gains from People, Lights, and Equipment These values are all determined by the size and function of the building, such as whether the building is a classroom, or is a factory, etc..

31 Gains From Latent Heat Latent Heat Gain is usually computed as a certain percentage of total sensible heat gain, depending on the climate and location of the structure. A minimum of 10% and a maximum of 30% are usually recommended.

32 Total All Heat Gains and Size HVAC Equipment Once all heat gains are computed for the summer, the necessary cooling equipment can be determined. And a very similar but much easier procedure is done for the winter in order to determine the heat loss through the building envelope, which helps determine the necessary size of the heating equipment.

33 Indoor Air Quality Water Efficient Tech Lighting Due to Time Constraints, I will not go into the particulars of each segments design.

34 Questions? Thank You For Your Time David Fuselier