Final Report – Porchdog House 48-733 Environmental Performance Simulation Xinxin Hu, Phillip Kuehne, David Suchoza, Victor Acevedo
Overall Abstract Solar, Visual, Thermal and Power Generation Studies of Porchdog House are conducted and analyzed integrated with multi-valent environmental design strategies into the early stages of performative architectures. This work explores the state-of-the-art architectural design & research oriented environmental performance simulation & visualization tools, methods and techniques (based on the algorithmic/parametric modeling ecosystem of RHINOGrasshopper-DIVA-ArchSIM-Ladybug-Honeybee programs).
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Table of Contents Overall Abstract .............................................................................................................................1
I. Climate Data and Site Strategies ......................................................................................... 4 Abstract .........................................................................................................................................4 1.1 Numeric Weather and Climate Analysis ....................................................................................5 1.2 2D and 3D Visualizations ..........................................................................................................7 1.3 Wind Rose and Wind Speed Analysis....................................................................................... 11 2.1 Solar Energy Density (SED) Effect on Building Orientation ........................................................ 12 3.1 Solar Energy Density (SED) Surface Comparison....................................................................... 25 4.1 Sun-Path Diagramming with Shadow Ranges .......................................................................... 32 6. Environmentally Responsive Landscape Design ......................................................................... 34 6.1 Static Shading Device.............................................................................................................. 35 7.1 Solar Fan Development........................................................................................................... 41
II. Visual Performance ......................................................................................................... 43 Abstract ....................................................................................................................................... 43 1.1 Visual Performance Alternatives and Unit Space ..................................................................... 44 2.1 Unaltered Living Room ........................................................................................................... 46 2.2 Alternative 1 – Local Shading .................................................................................................. 47 2.2 Alternative 1 – Local Shading .................................................................................................. 49 2.3 Alternative 2 – WWR and Light Shelf ....................................................................................... 50 2.4 Visual Acuity I Summary ......................................................................................................... 51 3.1 Unaltered Living Room ........................................................................................................... 52 3.2 Alternative 1 – Local Shading .................................................................................................. 55 3.3 Alternative 2 – WWR and Light Shelf ....................................................................................... 58 3.4 Visual Acuity II Summary ........................................................................................................ 60 4.1 Visual Comfort Introduction ................................................................................................... 61 4.2 Luminous Renderings and Unified Glare Rating (UGR) ............................................................. 62 4.3 Luminous Contrast and Visual Comfort Probability (VCP) ......................................................... 67 4.4 False Color and Daylight Glare Probability (DGP) ..................................................................... 71 4.4 Visual Comfort Summary ........................................................................................................ 75 5.1 Climate-Based Daylighting Evaluations: Unaltered Living Room ............................................... 76 5.2 Alternative 1 – Local Shading .................................................................................................. 80 5.3 Alternative 2 – WWR and Light Shelf ....................................................................................... 83 5.4 Climate-Based Daylight Summary ........................................................................................... 86
III. Thermal Performance ..................................................................................................... 87 Abstract ....................................................................................................................................... 87 1.0 Climate of Biloxi ..................................................................................................................... 89 1.1 Defining Thermal Zones .......................................................................................................... 91 1.2 Baseline Thermal Zone Properties ........................................................................................... 91 1.3 Alternative Properties ............................................................................................................ 93 2.1 Extreme Hot and Cold Week Temperature Analysis ................................................................. 99 2.2 Annual Operative Temperature Analysis ............................................................................... 112 2.3 Conclusion ........................................................................................................................... 114 2.4 Hourly Heat Gain/Loss: Occupants ........................................................................................ 115 2.5 Hourly Heat Gain/Loss: Electric Light Energy ......................................................................... 115 2.6 Hourly Heat Gain/Loss: Electric Equipment Energy ................................................................ 116
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2.7 Hourly Heat Gain/Loss: Window Transmitted Solar Radiation ................................................ 117 2.8 Hourly Heat Gain/Loss: Opaque Surface Conduction.............................................................. 118 2.9 Hourly Heat Gain/Loss: Infiltration........................................................................................ 119 2.10 Hourly Heat Gain/Loss: Total Ideal Loads Heating/Cooling Energy ........................................ 120 2.11 Hourly Heat Gain/Loss: Conclusion...................................................................................... 121 3.1 Heating & Cooling Energy Consumption: Baseline ................................................................. 122 3.2 Heating & Cooling Energy Consumption: ALT1 – Envelope Assembly Improvement ................ 124 3.3 Heating & Cooling Energy Consumption: ALT2 – Photo-Sensor Controlled Dimming ............... 126 3.4 Heating & Cooling Energy Consumption: ALT3 – Local Shading............................................... 128 3.5 Heating & Cooling Energy Consumption: ALT4 – Mixed-Mode Natural Ventilation ................. 131 3.5 Heating & Cooling Energy Consumption: Conclusion ............................................................. 134
IV. Power Generation ........................................................................................................ 135 1.1 Photovoltaic Design .............................................................................................................. 135 1.2 Photovoltaic Orientation Analysis ......................................................................................... 136 1.3 PV Array System ................................................................................................................... 137 1.4 PV Electrical Model (Ladybug) ............................................................................................... 138
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I. Climate Data and Site Strategies Abstract Environmentally responsive design requires a comprehensive understanding of climatic conditions at the project site to be able to assess the most effective solutions. This initial analysis of the climate data and site conditions sets the stage for more detailed analysis of visual and thermal performance in subsequent chapters. Located in climate zone 2A, Biloxi, MS is a relatively moderate cooling dominated climate with 1401 CDD and 975 HDD at 18.3°C. Prevailing winds come from the northeast and 70% of the year the outdoor drybulb temperature is within +/- 8°C of an acceptable temperature setpoint of 21°C. Studying how much solar radiation hits building surfaces is a critical component to understanding the impact of massing and orientation on a building’s heating and cooling strategy. The Porchdog house is oriented east/west in the long dimension with large windows (~55% WWR) on the east and west facades. Analysis of the solar energy density grid indicate the low slope roof and south-facing façade receive a majority of the incident solar radiation throughout the year – approx. 1650 W/m2 and 1050 W/m2 respectively. Seasonally, the south façade receives more solar radiation in the winter than in summer because of the lower, more normal angle of the sun relative to the vertical façade. Adding static shading devices can effectively block solar radiation during portions of the year where it would otherwise increase indoor solar heat gain during the cooling season. The dimensions of a shading device are the function of the window geometry and timeframe when solar radiation is undesirable. Adding static shading reduced the average annual solar energy density on a selected south-facing window from 1050 W/m2 to 539 W/m2 (48%). Additionally, shadow analysis can be helpful if working in a jurisdiction where access to daylight is required. This approach can also be applied at an urban scale using the solar fan tool. Climate and solar radiation analyses are critically important to the preliminary stages of the formation of a building or urban fabric.
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1.1 Numeric Weather and Climate Analysis In this assignment, the building case our group was assigned is the Porchdog house located in Biloxi, Mississippi. The data below displays detailed weather info for the location of the house.
Table 1.1 Weather Data
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Figure 1.2 Grasshopper Script displaying extracting EPW climate/location data above
Figure 1.3 Grasshopper Script displaying extracting EPW wind/global radiation data above
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1.2 2D and 3D Visualizations Biloxi, Mississippi is located in the Southeastern United States along the shore of the Gulf of Mexico. Due to its location, this climate tends to be more hot and humid when compared to the rest of the country. Temperatures tend to stay in the higher range, barely dipping below freezing. As a result, this climate is too hot and humid to be comfortable.
Figure 1.4 Yearly Dry Bulb Temperatures (°C) above, Relative humidity throughout the year (%) below
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Figure 1.5 Yearly Dry Bulb Temperatures (°C) upper left, Relative humidity throughout the year (%) lower right
Figure 1.4 & 1.5 above shows the temperature and relative humidity values throughout the year, but the 3D view allows us to see the range that these values can have in a single day or hour.
Figure 1.6 Yearly Dry Bulb Temperatures (°C) above, Relative humidity throughout the year (%) below
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Figure 1.7 Yearly Dry Bulb Temperatures (°C) above, Relative humidity throughout the year (%) below
Figures 1.6 & 1.7 above show the conditions when natural ventilation is optimal. These conditions are when the outdoor temperature is between 21 - 27°C and the relative humidity is between 30 – 50%. The only times of the year where it is relatively comfortable and natural means of ventilation can be used are during sparse times between late February to early June and late September to early November. The times all happen to be during midday as the this is when the humidity levels are not too high. In general, relative humidity levels over the course of the year tend to be lower during the midday as temperatures are higher, causing the air’s capacity to hold more water to increase. Most of the year has unfavorable conditions for natural ventilation and outdoor activity, so the use of mechanical systems is encouraged with periodic times where you can open a window.
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Figure 1.8 Grasshopper Script for displaying comfort levels throughout the year and determining best times to use natural ventilation above
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1.3 Wind Rose and Wind Speed Analysis
Figure 1.9
The wind rose above shows that the prevailing winds are coming from the Northeast. The winds from the Northeast and South are the most frequent while the winds from the North/Northwest are the strongest. The wind speeds were calculated from a height of 5 meters, approximately the midway height of the building.
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2.1 Solar Energy Density (SED) Effect on Building Orientation
Figure 3.1 Southern Annual Solar Radiation Perspective – Base Orientation
Figure 3.2 Northern Annual Solar Radiation Perspective – Base Orientation
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Figure 3.3 Northwest Summer Solar Radiation Perspective– Base Orientation
Figure 3.4 Northeast Summer Solar Radiation Perspective – Base Orientation
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Figure 3.5 Southern Winter Solar Radiation Perspective – Base Orientation
Figure 3.6 Northern Winter Solar Radiation Perspective – Base Orientation
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The first rotation of the building on the site was a turning it from having it perpendicular to north and south and turned it 60˚ towards to the north. The thought behind this was that the building would receive more northern daylight in the six big windows in the afternoon.
Figure 3.7 Southeast Annual Solar Radiation Perspective - 60˚ turn
Figure 3.8 Northwest Annual Solar Radiation Perspective – 60˚ turn
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Figure 3.9 Southeast Summer Solar Radiation Perspective- 60Ëš turn
Figure 3.10 Northwest Summer Solar Radiation Perspective - 60Ëš turn
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Figure 3.11 Southeast Winter Solar Radiation Perspective – 60˚ turn
Figure 3.12 Northwest Winter Solar Radiation Perspective - 60˚ turn
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The next alternate orientation was rotating the building 180Ëš. So, the building is totally flipped on the site, and we wanted to see if doing this would change the amount of radiation on the east and west elevations. It was also changed to be able to have bigger windows on the west side for natural ventilation. After running the simulation, I did realize it is not too smart to place a lot of glazing on the west side of the building.
Figure 3.13 South Annual Solar Radiation Perspective - 180Ëš turn
You can also see in figure 3.13 the red in the lower corner of the southern wall. This is actually solar radiation protection from the one tree I hide in the view to see the building. Like I was saying earlier this section that the site context can help use protect the building. In the image you can also realize that the tress around the building are deciduous trees, because with the annual simulation you can see that it helps shade in the summer. Then the tree will drop the leaves at the end of the growing season so then it will not help protect the solar radiation in the winter time.
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Figure 3.14 North Annual Solar Radiation Perspective - 180˚ turn
Figure 3.15 South Summer Solar Radiation Perspective - 180˚ turn
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Figure 3.17 North Summer Solar Radiation Perspective - 180Ëš turn
Figure 3.18 South Winter Solar Radiation Perspective - 180Ëš trun
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Figure 3.19 North Winter Solar Radiation Perspective- 180Ëš turn
Our final iteration for the building orientation was rotation the building to the right towards southeast on a 45Ëš. When rotating this I was thinking of the east and west glazing and trying to maybe control the amount of direct sunlight onto the glazing, With the rotation it would maybe get less solar radiation to help with heat and gain and heat loss on both east and west side the building. It just hard to justify rotating the building with not having a lot of site context to shade or not shade the building.
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Figure 3.20 South Annual Solar Radiation Perspective- 45˚ turn
Figure 3.21 North Annual Solar Radiation Perspective - 45˚ turn
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Figure 3.22 South Summer Solar Radiation Perspective - 45Ëš turn
Figure 3.23 North Summer Solar Radiation Perspective - 45Ëš turn
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Figure 3.24 South Winter Solar Radiation Perspective - 45Ëš turn
Figure 3.25 North Winter Solar Radiation Perspective - 45Ëš turn
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3.1 Solar Energy Density (SED) Surface Comparison In the SED comparison there was a simulation for an annual sun path through the year in Biloxi, Mississippi. There was also a seasonal comparison between the winter and summer sun paths. You can see with the simulation imagery that the solar radiation on the building.
Figure 4.1 East Annual Solar Radiation Elevation
Figure 4.2 West Annual Solar Radiation Elevation
The annual solar radiation looks like the sun overheats the surface of the building but there is not the much coverage from the site context around the building. I would say once the two trees around the building are bigger it will help with the amount of direct sun to the roof, south and west side of the building. In figure 4.3 it shows the south side of the building is getting over 1000 kWh/m2 of annual solar radiation and if the site would have some more site context it could help with the impact on the southern side of the building.
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Figure 4.3 South Annual Solar Radiation Perspective
Figure 4.4 North Annual Solar Radiation Elevation
Figure 4.5 South Annual Solar Radiation Elevation
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Figure 4.6 Northern Annual Solar Radiation Perspective
The Winter solar radiation has a low impact of the exterior of the building. With this building being located in Mississippi it gets a reasonable amount of solar radiation for the sun being lower in the sun.
Figure 4.8 West Winter Solar Radiation Elevation
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Figure 4.9 East Winter Solar Radiation Elevation
Figure 4.10 Southern Winter Solar Radiation Perspective
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Figure 4.11 Northern Winter Solar Radiation Perspective
Figure 4.12 South Winter Solar Radiation Elevation
Figure 4.13 North Winter Solar Radiation Elevation
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Figure 4.14 East Summer Solar Radiation Elevation
Figure 4.15 West Summer Solar Radiation Elevation
Figure 4.16 Southern Summer Solar Radiation Perspective
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Figure 4. 17 South Summer Solar Radiation Elevation
4.18 North Summer Solar Radiation Elevation
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4.1 Sun-Path Diagramming with Shadow Ranges To construct sun path diagrams with shadow ranges throughout the year, four specific days have been chosen to show the sun path and the shadow area changing process. The sun path diagram and the shadow ranges are shown separately because the Rhino I use has some trouble showing them in one view point.
Figure 4.1 Winter Solstice (Dec. 21)
Figure 4.2 Spring Equinox(Mar.21)
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Figure 4.3 Summer Solstice (Jun. 21)
Figure 4.4 Autumn Equinox (Sep. 21)
From the images above, the highest sun angle (83°) is at the summer solstice on 12:00pm Jun 21 and the lowest sun angle (1.36°) is at the winter solstice on 7am Dec 21. Because Biloxi located at the north part of the earth and the sun moves to the south part of the earth in winter where the sun location is at the lowest position.
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6. Environmentally Responsive Landscape Design In order to help landscape designer to avoid the ground plane at the vicinity of the building case that receive less than 6-hours of direct sunlight between 9am and 3pm on Dec 21(winter solstice), a sunlight hours analysis is conducted by ladybug. From the result given in the Figure 3.1, 77% of the site(5720m2) receives less than 6-hour of direct sunlight between 9am to 3pm, which is also shown in the Figure 6.1. And 13% of site (76.7m2) receives enough 6-hour of direct sunlight between 9am to 3am. The total site area is 7459m2. The shadow area is the land receives less than 6 hours direct sunlight including the land shaded by the buildings.
Figure 6.1 Sunlight Hours Analysis Output
Figure 6.2 Sunlight Hours Analysis Visualization
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6.1 Static Shading Device A solar fan was generated for each window to determine the geometry needed to shade the windows during the time of year when solar radiation hitting the glazing surface would be undesirable. As mentioned above, the spring and fall equinoxes were used as cutoff dates whereby the glazing surfaces are shaded during the warmer half of the year between those dates. At these cutoff dates, the south faรงade experiences solar exposure from approx. 6:30 until 18:00 and so the altitude angle varies from the low point at these times and the high point slightly before 12:00. Figure 6.1 illustrates the solar fan volume for each window and the responsive shading geometries designed to block solar exposure during this time of year. Each shading geometry is different because each window is a different size and the shading is generated as a function of the window dimensions and solar angles during the specified timeframe. For example, the shading device is longer and deeper when the window is taller and the opposite is true for shorter windows. See elevation views below.
Figure 6.1 Solar Fan Static Shading Cutoff Zones
Figure 6.2 Static Shading Cutoff Angles
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The Porchdog House has four south-facing punched windows of varying proportions as seen in Figure 6.1 above. To design effective static shading devices, critical solar angles are important to study as well as the date range (or shading period) in which the shading devices will block the sun when direct solar on glazed portions of the thermal envelope are least desirable. Generally, the effective shading period in the northern hemisphere is from Spring Equinox (March, 21) to Fall Equinox (September, 21). However, a more accurate date range can be extracted from weather data files by analyzing the intersection points of the annual HDD and CDD curves. When the HDD curve is greater than CDD, it means the climate has shifted from cooling demand to heating demand, thus eliminating the need to prevent solar gain. Figure 6.4 below illustrates the cutoff dates on the graph but further investigation is needed to determine the actual coordinate location.
Figure 6.3 First Frost Day
Figure 6.4 HDD and CDD Curves
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Figures 6.5 – 6.7 show a detailed elevation view of the fixed shading design. The annual SED shown in Figure 6.5 below represents a 48% average reduction in SED as compared to the same window without fixed shading. Also, the design limitations of this shading design are evident by comparing the 122 kWh/m2 value in Figure 6.6 to 282 kWh/m2 in Figure 6.7. This comparison indicates the shading is more effective in the summer under cooling demand conditions than it is in winter. This result achieves the design intent of the shading device given the cutoff dates described above.
Figure 6.5 Annual SED - Elevation Detail at South-Facing Window (values in kWh/m2)
Figure 6.6 Summer SED - Elevation Detail at South-Facing Window (values in kWh/m2)
Figure 6.7 Winter SED - Elevation Detail at South-Facing Window (values in kWh/m2)
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Figures 6.8 – 6.9 illustrate several Solar Energy Density (SED) values on the south façade at different time intervals. It is clear the south façade experiences more solar exposure in winter than in the summer. The values noted below are solar energy density (kWh/m2).
Figure 6.8 Annual SED w/o Shading (south view)
Figure 6.9 Annual SED w/ Shading (south view)
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Figure 6.10 Summer SED w/o Shading (south view)
Figure 6.11 Summer SED w/ Shading (south view)
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Figure 6.12 Winter SED w/o Shading (south view)
Figure 6.13 Winter SED w/ Shading (south view)
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7.1 Solar Fan Development Figures 7.1 & 7.2 below illustrate the before and after conditions of the solar fan study. A significant portion of the playground site (represented by the colored analysis grid) is shaded between the cutoff dates in the spring and fall. The cutoff dates were determined by the average date of first frost (FF) in the fall and the average date of last frost (LF) in the spring. The values noted below are average annual solar energy densities (kWh/m2) for the entire playground site.
Figure 7.1 Existing Urban Massing Annual SED
Figure 7.2 Modified Urban Massing Annual SED
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The solar fan represents the spatial volume inside which there should not be any obstructions to satisfy the desired amount of solar radiation. In this analysis, it was determined the entire playground area was to receive a minimum of 6 hours of sunlight for the time of year between the First Frost Day and Last Frost Day. Figure 7.2 illustrates how the surrounding urban massing was modified to achieve the required amount of daylight. The surfaces highlighted in red were trimmed from the original massing. The increase in average solar energy density from Figure 7.1 to 7.2 indicates the success of the modified massing. Furthermore, the modified geometry in Figure 7.2 illustrates which direction most sunlight comes from during the growing season. In this study, the solar fan geometry and modified urban context reveal most sunlight is coming from the south and west. This is also indicated by the site areas receiving less solar energy in Figure 7.1.
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II. Visual Performance Abstract The Porchdog House has large expanses of glazing on the east/west facades and only small windows to the north and south. The living room was selected as the unit space for the visual performance analysis because it includes both east and south facades and is a frequently-used space in the home. Three simulation alternatives were used to investigate visual performance metrics including visual acuity, daylight autonomy, daylight illuminance, annual daylight exposure and visual comfort. The results of the visual comfort analysis highlight the challenge of shielding spaces from direct sunlight in the east/west direction. In this orientation, neither horizontal or vertical shading are completely effective for blocking direct sunlight. Instead, the most successful strategy for mitigating glare for east-facing glazing appears to be diffusion as it produced the highest visual comfort probability (VCP) and lowest unified glare index (UGP). This strategy will effectively scatter the direct light and still allow visible transmittance throughout the day. One caveat to this approach is that views are blocked and this should be balanced against biophilic benefits of a visible connection to nature. The baseline design performed adequately for daylight illuminance in the space, but could be improved upon. Installing shading devices helped improve the morning performance as the downfall of the original design are the huge Eastern windows letting in so much light causing high amount of glare. However, the amount of shading added to the south and eastfacing windows reduced afternoon daylight illuminance to unacceptably low levels. Alternative 2 dealt with adding windows to the southern faรงade and a light shelf. This design worked well in terms of the distribution of illuminance and reducing contrast in the space. The analysis of spatial daylight autonomy (sDA) and annual solar exposure (ASE) further highlight the balance between shading and visual performance. When shading was added to the south and east windows, it resulted in a decrease in sDA and ASE, indicating a increased reliance on artificial lighting. Adding light shelf helped achieve a more uniform illuminance distribution. To further reduce ASE, some strategies could be implemented including reduced visual transmittance, adding solar film as a shading device or decrease WWR at east faรงade and so on. Finally, baseline case will be chosen as the best case since it fulfills 55% limit of sDA and has higher UDI.
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1.1 Visual Performance Alternatives and Unit Space The baseline model in Figure 1.1 and consists of the typical building envelope with no shading devices on the exterior glazing. The unit space chosen for analysis was the living room as it is a central space in the home and has exterior glazing facing both east and south. Alternative 1 in Figure 1.2 below looks at local shading devices on the south and east glazing. Vertical shading was proposed for the east and horizontal glazing on the south. Alternative 2 in Figure 1.3 below looks at increasing the WWR on the south façade and adding a light shelf with horizontal static shading below the light shelf.
Figure 1.1 – Baseline Model
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Figure 1.2 – Alternative 1
Figure 1.3 – Alternative 2
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2.1 Unaltered Living Room
The grid-based daylight factor showed how far the sunlight truly travels into the space through the giant north facing windows. In the image above the amount of daylight on the surface is to high for the living room. With the average daylight factor being 10.66 it is high for the average percentage for a residential living space. This can help with the electricity bill, because during the daylight hours you will not need much electric lighting in the room. Only place the electric lighting that might need to be turned on will be towards the south facade of the building.
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2.2 Alternative 1 – Local Shading
The grid-based daylight factor showed how far the sunlight truly travels into the space through the giant east facing windows. In the image above the amount of daylight on the surface is larger than the daylight limits in a residential living room. You can see in figure 2.1.1 that a good goal to reach for in a residential living room is 1.5 % of the room is lit by daylight. The mean daylight factor for our living is 5.34 lux per square. So, compared to limits of daylight factor percentage we are getting on average a higher percentage of daylight per area. The grid is also offset 0.9 m off the ground to simulate the daylight factor on the surfaces that you will be working on. You can see in figure 2.2 that you should not place anything to work on to close the glazing, because you will have to deal with the glare and overheating being so close the glazing. The spacing of the grid is .2 m away from each other and trying get a good resolution of the daylight factor that is represented in the above figure. With looking at the simulation of the unaltered room the only lighting you might need would be deeper in the room near the west façade.
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Figure 2.1.1 Daylight Factor Limits
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2.2 Alternative 1 – Local Shading
Figure 2.2 Local Shanding Alternative
This grid-based daylight factor here is using local shading on the East façade of the building to control the amount of direct daylight into the living room. When adding the local shading devices to the glazing it helped reduce the mean daylight factor to 3.24 lux per square and you can see that in Figure 2.2.1. Adding the local shading to the east and south glazing we are able to see the amount of daylight in the room go down. Just adding the shading devices, we went from 5.35 lux per square to 3.24 lux per square and that is a big jump. Every square in the figure is .2 m big and you can see that shading devices allow will help you with the amount of daylight into the living room. Even with adding the shading you can use a light material on the floor to be able to bounce the light farther into the space. This grid-based image is also offset from the floor 0.9 m so you imagine that is the height of your work surface.
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Figure 2.2.1 Local Shading Alternative Grasshopper Script
2.3 Alternative 2 – WWR and Light Shelf
Figure 2.3 WWR and Light Shelf Alternative
This grid-based daylight factor with the WWR and light shelf didn’t take care of the daylight factor well. It is a good idea to have a good WWR, but the east facade already gives enough daylight into the east side of the building. Adding more window towards the south might 50
not be the ideal motion but placing them closer to the back might give the opportunity to get the maximum amount of daylight through the whole space. When running it in the script you can see in figure 2.3.1 that the mean daylight factor is 5.49 lux per square. Looking back at both the original base room and the local shading this alternative is the just ideal at all.
Figure 2.3.1 WWR and Light Shelf Alternative Grasshopper Script
2.4 Visual Acuity I Summary Overall, the east facade gives the building most of the daylight they would need when the sun is on that side of the building. With looking at the three different alternatives the local shading does the best job with giving the space an even amount of daylight with controlling the bad direct sunlight that we don’t want to have. It gives the best results with 3.24 lux per square which gets the closest to the 1.5 % daylight limit for a residential living room. Merging both the WWR and light shelfs with the local shading I think could make the perfect match. You would be able to get enough light through the whole space throughout the day. This might allow for minimal electric lighting as well. Also, moving the south glazing back away from the east facade to separate the daylighting on the east side. The sun is not always going to be on the east side of the building all day and year. So electric lighting might need to be used when the sun is setting in the afternoon and night time.
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3.1 Unaltered Living Room The room chosen for the Visual Acuity Evaluations was the living room as this is the space most likely to be occupied the most, thus making it the main space in the house. The Grid spacing for the analysis is 0.2 meters while the offset is 0.8 meters. The sky conditions chosen was a CIE Clear Sky with sun model and the ground is set with a 0.2 reflectance. These settings were applied to each of the grid-based illuminance simulations in this section of the report.
Figure 2.A.1 Grid-Based Daylight Illumination for March 21st at 9am
63% of the floor area was between 300 lux and 3000 lux with an average of about 8783 lux. The lux values greatly vary from a low of 0 lux to a high of 47410 lux
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Figure 2.A.2 Grid-Based Daylight Illumination for March 21st at 3pm
64% of the floor area was between 300 lux and 3000 lux with an average of about 523 lux. The lux values greatly vary from a low of 0 lux to a high of 4709 lux
Figure 2.A.3 Grid-Based Daylight Illumination for September 21st at 9am
67% of the floor area was between 300 lux and 3000 lux with an average of about 7924 lux. The lux values greatly vary from a low of 0 lux to a high of 48465 lux
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Figure 2.A.4 Grid-Based Daylight Illumination for September 21st at 3pm
62% of the floor area was between 300 lux and 3000 lux with an average of about 504 lux. The lux values greatly vary from a low of 0 lux to a high of 4700 lux
Grid-based illumination factor shows the sunlight coming into the room and bouncing off the surfaces. This is an important factor to consider as interior surfaces have different reflective qualities and can impact the amount of glare inside. Also, the orientation and size of windows can impact the amount of light entering, thus impacting the amount of light that is illuminated/reflecting off of surfaces. There needs to be a good amount of glare as too little would make the space dark inside, while too much would cause discomfort and make it hard to see. During the 9 am simulations, the sun is still towards the Southeast and not in its’s peak altitude, causing concentrated light to enter on both the Southern and Eastern facades. Due to the sun not being positioned high in the sky, the light is able to travel deeper in the space causing more areas of reflection/glare. The size of the windows also has a big impact as the light can penetrate deep in the space in the morning hours because the largest windows are located on the Eastern façade. During the 3 pm simulations, the sun is located towards the Southwest, reducing the impact of glare and solar penetration on the Eastern façade. There is still a small concentration of glare/illuminance coming in from the southern window.
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3.2 Alternative 1 – Local Shading
Figure 2.B.1 Grid-Based Daylight Illumination with Local Shading for March 21st at 9am
65% of the floor area was between 300 lux and 3000 lux with an average of about 4514 lux. The lux values greatly vary from a low of 153 lux to a high of 40808 lux
Figure 2.B.2 Grid-Based Daylight Illumination with Local Shading for March 21st at 3pm
47% of the floor area was between 300 lux and 3000 lux with an average of about 288 lux. The lux values greatly vary from a low of 43 lux to a high of 4491 lux
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Figure 2.B.3 Grid-Based Daylight Illumination with Local Shading for September 21st at 9am
67% of the floor area was between 300 lux and 3000 lux with an average of about 3716 lux. The lux values greatly vary from a low of 130 lux to a high of 42388 lux
Figure 2.B.4 Grid-Based Daylight Illumination with Local Shading for September 21st at 3pm
62% of the floor area was between 300 lux and 3000 lux with an average of about 283 lux. The lux values greatly vary from a low of 38 lux to a high of 4462 lux
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The addition of local shading devices on the windows did help to reduce the high levels of glare and the overall illumination of the space. This had a positive impact on the morning sun as the high levels of illuminance were reduced while the darker areas were more evenly lit. The afternoon sun was negatively impacted as these numbers were not high to begin with and were reduced even more. Although the glare on the eastern faรงade was greatly taken care of, the illuminance levels in the rest of the room dipped below the minimum acceptable amount of 300 lux.
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3.3 Alternative 2 – WWR and Light Shelf
Figure 2.C.1 Grid-Based Daylight Illumination with WWR and Light Shelf for March 21 st at 9am
73% of the floor area was between 300 lux and 3000 lux with an average of about 9126 lux. The lux values greatly vary from a low of 230 lux to a high of 47548 lux
Figure 2.C.2 Grid-Based Daylight Illumination with WWR and Light Shelf for March 21 st at 3pm
74% of the floor area was between 300 lux and 3000 lux with an average of about 622 lux. The lux values greatly vary from a low of 141 lux to a high of 4593 lux
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Figure 2.C.3 Grid-Based Daylight Illumination with WWR and Light Shelf for September 21 st at 9am
71% of the floor area was between 300 lux and 3000 lux with an average of about 8309 lux. The lux values greatly vary from a low of 235 lux to a high of 48407 lux
Figure 2.C.4 Grid-Based Daylight Illumination with WWR and Light Shelf for September 21 st at 3pm
72% of the floor area was between 300 lux and 3000 lux with an average of about 589 lux. The lux values greatly vary from a low of 131 lux to a high of 4480 lux The addition of the light shelf and WWR helped bring in more light overall into the space. This light is better than the direct light that was entering the space in the original design as this light is diffused by the light shelf, reducing contrast/glare. The lower lux values increased while the lower values decreased, creating a more pleasant space. 59
3.4 Visual Acuity II Summary
Figure 3.4 Table Showing the Percentage of the Living Room with Acceptable Illuminance Levels (between 300 lux and 3,000 lux)
The original design did fine overall in the amount of illuminance in the space, but could be improved upon. The first alternative dealt with installing shading devices which helped improve the morning performance as the downfall of the original design are the huge Eastern windows letting in so much light causing high amount of glare. The problem with this alternative is that the amount of illuminance is greatly reduce in the afternoon which causes levels to be unacceptably low. The second alternative dealt with adding windows to the southern faรงade and a light shelf. This design worked well in terms of the distribution of illuminance and reducing contrast in the space. The percentage of the room with the acceptable range increased but the high amount of glare/illuminance levels still exist on the Eastern side. The combination of both alternatives would produce a better result. The reason for this is that the shading devices on the eastern faรงade would reduce the high illuminance values coming in in the morning, the light shelf to the south would diffuse light and lessen the contrast/glare, while the increased WWR on the southern faรงade would help balance the below average values with an increase in light.
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4.1 Visual Comfort Introduction Visual comfort will be analyzed using three metrics: UGR, VCP and DGP. These three metrics will be analyzed for three dates throughout the year These three metrics will be analyzed for four model variations. In addition to the three models outlined in the abstract, a fourth model was developed to explore another strategy for effectively improving visual comfort. In each variation, the orientation of the space is constant, where the east exterior wall contains a large expanse of glazing, making the morning hours the most critical time of day effecting visual comfort. The results in the subsequent sections will be compared to the following glare thresholds in Table 4.1 below. Table 4.1 - Glare Thresholds Glare Thresholds UGR
VCP
DGP
< 13
80 - 100
< 0.35
Perceptible Glare
13 -22
60 -80
0.35 - 0.40
Disturbing Glare
22 - 28
40 - 60
0.40 - 0.45
Intolerable Glare
> 28
< 40
> 0.45
Imperceptible Glare
Table 4.2 - Baseline Results Baseline Date 3/21/18 6/21/18 12/21/18
Time
UGR
VCP
9:00
25.3
10.1
DGP 0.3
15:00
25.1
11.4
0.24
9:00
24.9
12.2
0.27
15:00
25.1
11
0.24
9:00
25.3
13.7
0.29
15:00
24.6
21.3
0.23
Table 4.3 - Alternative 1 Results Alternative 1 Date 3/21/18 6/21/18 12/21/18
Time
UGR
VCP
DGP
9:00
25.6
12.3
0.27
15:00
24.1
26
0.23
9:00
24.6
14.4
0.26
15:00
24.1
25.4
0.23
9:00
26.6
12.2
0.25
15:00
23.9
28.7
0.21
Table 4.4 - Alternative 2 Results Alternative 2 Date 3/21/18 6/21/18 12/21/18
Time
UGR
VCP
DGP
9:00
25.1
17
0.31
15:00
26.3
14.6
0.25
9:00
25.2
15.6
0.29
15:00
26.1
14.9
0.25
9:00
26.1
16
0.31
15:00
25.8
15.7
0.24
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Table 4.5 - Translucent Screen Results East Translucent Screen Date 3/21/18 6/21/18 12/21/18
Time
UGR
VCP
DGP
9:00
24
18.6
0.24
15:00
19.5
46.4
0.07
9:00
23.7
34.5
0.24
15:00
19
49.8
0.06
9:00
23.1
28.2
0.23
15:00
21
53.8
0.05
Figure 4.1 Translucent Screens
The translucent screen material has a visual transmittance of 20%, meaning only 20% of the visible light is transmitted through the material. This can be a more effective strategy for glare control on east/west facades than fixed shading because of the dynamic way the sun moves across those sides of the building.
4.2 Luminous Renderings and Unified Glare Rating (UGR) The luminous renderings shown below in Figures 4.4 â&#x20AC;&#x201C; 4.6 compare each of the model alternatives. As expected, visual discomfort is more apparent at 9am than 3pm because the east-facing glazing receives direct sunlight. There is also a direct correlation between morning and afternoon glare performance as well as performance across the three dates. Overall, the performance rank is as follows (best to worst): Translucent Screen, Alternative 1, Baseline, Alternative 2.
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UGR values range from 13 to 28 with lower values indicating less glare and higher visual comfort. Figures 4.2 and 4.3 below compare the UGR values from all alternatives at 9am and 3pm. It is clear from these charts that the morning direct sunlight is a persistent challenge for visual comfort. Without designing dynamic shading, it would be quite difficult to achieve both high levels of visual comfort and daylight autonomy. UGR levels remain in the Disturbing Glare category for all models at 9am but the Translucent Screens model shows a sizeable improvement at 3pm and jumps up a category to Perceptible Glare. These results highlight the effectiveness of diffusely scattering light as opposed to trying to block it entirely for some portion of the day/year.
Figure 4.2 â&#x20AC;&#x201C; UGR at 9am
Figure 4.3 â&#x20AC;&#x201C; UGR at 3pm
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Figure 4.4 - March 21 Luminous Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.5 - June 21 Luminous Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.6- December 21 Luminous Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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4.3 Luminous Contrast and Visual Comfort Probability (VCP) The target range for VCP is > 60 which was not achieved by any of the models. The comparison between models in Figures 4.7 and 4.8 below shows that vertical shading on the east façade (Alternative 1) was not effective for increasing the VCP. In general, the performance ranking for VCP is as follows (best to worst): Translucent Screen, Alternative 1, Alternative 2, Baseline. Figures 4.7 and 4.8 indicate that visual comfort improved slightly with Alternative 2 as compared to the baseline. The additional luminance from the increased south WWR and light shelf increased the room’s overall brightness, thus decreasing contrast and glare. The Translucent Screen performed the best both at 9am and 3pm and was the only alternative to approach the acceptable VCP range. Note also in Figure 4.11 that the luminous contrast on the east façade is the most extreme in the winter because the sun is low in the sky. During the winter solstice, even the shading below the light shelf in Alternative 2 is not effective at blocking direct sunlight because of the low altitude angle.
Figure 4.7 – VCP at 9am
Figure 4.8 – VCP at 3pm
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Figure 4.9 - March 21 Luminous Contrast (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.10 - June 21 Luminous Contrast (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.11 - December 21 Luminous Contrast (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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4.4 False Color and Daylight Glare Probability (DGP) Unlike UGR and VCP, the lower the value of DGP, the better and the target range for DGP is < 0.40. The performance rank of all models is as follows (best to worst): Translucent Screen, Alternative 1, Baseline, Alternative 2. Although the overall performance across each alternative follows the same pattern as the results from UGR and VCP above, one important distinction here is that the DGP values for all models are categorized as Imperceptible Glare per Table 4.1. Similar results can also be seen from the DGP readout in the top left corner of each simulation view where the DGP values are always listed as Imperceptible. From Figures 4.14 – 4.16 it’s apparent that Alternative 1 reduces the luminance of the space throughout the year but interestingly, this doesn’t seem to translate into any meaningful reduction in glare. Perhaps this could be because of the reflection bouncing off of the white vertical shading and also because the shading doesn’t block all direct sunlight.
Figure 4.12 – DGP at 9am
Figure 4.13 – DGP at 3pm
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Figure 4.14 - March 21 False Color Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.15 - June 21 False Color Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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Figure 4.16 - December 21 False Color Renderings (col L to R: 9AM, 3PM) (row T to B: Baseline, Alt 1, Alt 2, Translucent Screen)
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4.4 Visual Comfort Summary The results of the visual comfort analysis highlight the challenge of shielding spaces from direct sunlight in the east/west direction. Neither horizontal or vertical shading are completely effective for blocking direct sunlight. Instead, the most successful strategy for mitigating glare for east-facing glazing appears to be diffusion. This strategy will effectively scatter the direct light and still allow visible transmittance throughout the day. One caveat to this approach is that views are blocked and this should be balanced against biophilic benefits of a visible connection to nature.
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5.1 Climate-Based Daylighting Evaluations: Unaltered Living Room Climate-based daylight performance simulation was conducted in Diva-Grasshopper. Spatial Daylight Autonomy, Annual Sunlight Exposure and Useful Daylight Illuminance were calculated to analyze the daylight performance. •
Basic Simulation Information: 1. The analysis grid surface is at 0.2*0.2 m and placed 0.8 m above the finished floor surface as the desk level. 2. Occupancy Schedule: in the simulation, 8am to 6pm schedule was applied since there is no available residential schedules for simulation. And other schedules are not appropriate for daylight performance analysis. 3. Building Materials Assignment:
•
Performance Metrics: 1. sDA≥55%, spatial daylight autonomy is the percentage of floor space in which a minimum light level can be met completely for some proportion of regular operating hours by natural light. In this simulation study, we investigated the percentage of the floor area that receives at least 300 lux only from daylight for at least 50% of the annual occupied hours in a year, where 300 lux is the minimum physical lighting 76
requirement that has to be maintained so that certain visual tasks can be performed comfortably by the working occupant. 55% is the minimum sDA criteria for well daylit spaces out of the total floor area of living room. 2. ASE1000lux-250hrs≤10%, ASE stands for annual sunlight exposure that is the percentage of space in which the light level from direct sun alone exceeds a predefined threshold for some quantity of hours in a year. In the simulation study, we used the 1000 lux as the minimum illuminance threshold causing overheating and glare problems and 250 hours as the minimum occupied hours annually. 10% is the maximum ASE criteria to prevent negative effects including thermal discomfort and glare. 3. UDI: useful daylight illuminance [%] is the times when indoor daylight levels are useful for the occupants form the point of visual comfort. Useful means that indoor conditions are neither too dark nor too light. Daylight illuminance should larger than 100 lux and smaller than 2000 lux. •
Simulation Output
Figure 4.A.0 sDA, ASE & UDI output of unaltered Living Room
According to Figure 4.A.0, the spatial daylight autonomy is 58.9% which means 58.9% of the floor surface could receive 300 lux in time period of at least 50% of occupied hours. As shown in Figure 4.A.1, the floor area nearby the east window and south window receives enough daylight at daytime. But the surface at north and west part of the room is not well daylit because of the furniture and no window openings on North façade and west façade.
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Figure 4.A.1 Daylight Autonomy
Figure 4.A.2 Useful Daylight Illuminance
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Figure 4.A.3 Annual Sunlight Exposure
According to Figure 4.A.0, the useful daylight illuminance is 64% which means 64% of the work plane could receive useful daylight level between 100 lux and 2000 lux. From the Figure 4.A.2, the room is well daylit and illuminance distribution is uniform. The annual sunlight exposure is 46% meaning that 46% of the floor area receiving at least 1000lux only from daylight for at least 250 hours of the annual occupied hours annually. Corresponding to the Figure 4.A.2 and 4.A.1, the floor area that nearby the window receives excessive daylight and it may cause thermal discomfort and glare. This is due to large window area allowing excessive direct sun into the room and no daylighting redirecting facilities to illuminate the inner room.
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5.2 Alternative 1 â&#x20AC;&#x201C; Local Shading In this alternative 1, we added local shading on the glazing part. Vertical fins and overhangs were installed on east and south glazing parts respectively. After adding shading devices, sDA, ASE and UDI all dropped down. Although Annual sunlight exposure becomes better, daylight autonomy and useful daylight illuminance decreases which means less floor area receives useful and enough daylight throughout the year as shown in Figure 4.B.0.
Figure 4.B.0 sDA, ASE & UDI level of alternative 1 local shading simulation
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Figure 4.B.1 Daylight Autonomy of alternative 1 East & West shading
From Figure 4.B.1, inner grid surface that are nor well daylit due to the distance from the east and south glazing.
Figure 4.B.2 Useful Daylight Illuminance of alternative 1 East & West shading
The northwest part of the grid surface are not well daylit and receives less than 100 lux according to Figure 4.B.2 and Figure 4.B.3.
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Figure 4.B.3 Annual Sunlight Exposure of alternative 1 East & West shading
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5.3 Alternative 2 â&#x20AC;&#x201C; WWR and Light Shelf In alternative 2, more glazing is added on south façade and a light shelf is added to redirect daylight into north and west part of the room. According to the simulation result shown in Figure 4.C.0, daylight autonomy level and useful daylight illuminance increase a little bit while annual sunlight exposure also increases at the same time. The east part of the studied grid surface was exposed to excessive sunlight due to large east glazing area with no shading devices shown in Figure 4.C.2 and Figure 4.C.1. For useful daylight illuminance, it increased from 64 to 65 based on 4.A. So there is no much difference for the difference. But comparing Figure 4.B.2 and Figure 4.C.3, adding light shelf could make the illuminance distribution more uniform in north and west part of the studied grid surface.
Figure 4.C.0 sDA, ASE and UDI outputs of alternative 2
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Figure 4.C.1 Daylight Autonomy for revised WWR and installed Light Shelf
Figure 4.C.2 Annual Sunlight Exposure for revised WWR and installed Light Shelf
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Figure 4.C.3 Useful Daylight Illuminance for revised WWR and installed Light Shelf
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5.4 Climate-Based Daylight Summary Baseline Unaltered Living Room sDA300lux-50% 58 (%) ASE1000lux-250hrs 46 (%) UDI (%) 64
Alternative 1 Alternative 2 Alternative 3 With East With West & Alternated WWR Shading East Shading and Light Shelf 42.2
38
64
32.2
29
50
40
57
65
One more alternative (Alternative 1) was created for only applying vertical fins on west shading to get enough daylight from the south glazing. The result is shown in Figure 4.D.1. Daylight autonomy was better than applying both shading on west and east glazing while ASE and UDI are worse.
Figure 4.D.1 sDA, ASE and UDI output of Alternative 1 – Local Shading
To summarize, all alternatives and baseline don’t fulfil the requirement of 10% limit of annual sunlight exposure. And only alternative 3 and baseline fulfil the sDA requirement of 55%. When shading is added, illuminance level dropped down so that sDA and ASE decreases while UDI depends on the area that receives larger than 100 lux and smaller than 2000lux. Adding light shelf do help more uniform illuminance distribution. To further reduce ASE, some strategies could be implemented including reduce visual transmittance, adding solar film as a shading device or decrease WWR at east façade and so on. Finally, baseline case will be chosen as the best case since it fulfills 55% limit of sDA and have higher UDI.
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III. Thermal Performance Abstract Detailed building envelope properties, internal loads and mechanical systems were investigated in this chapter. The Porchdog House was first parsed into thermal zones which were defined according to space use type and orientation. Several spaces were categorized as unconditioned because of their transient functions. Four simulation alternatives were generated to explore a range of environmental criteria and their impacts on thermal performance. -
ALT 1: Envelope Assembly Improvements ALT 2: Photo-Sensor Controlled Dimming ALT 3: Local Shading ALT 4: Mixed-Mode Natural Ventilation
Different strategies were explored in each of the simulation alternatives for mitigating heat gain & loss at different times of day. Increasing the U-value of the exterior wall, roof and exterior floor assemblies in ALT 1 showed the most success in mitigating heating loads for most analysis metrics. An observable effect of photo-sensor dimming controls (ALT 2) was only apparent on the lighting energy loads. While dimming controls significantly reduced electric lighting energy during the daytime, its effectiveness is limited for residential application as the house is scheduled to use much less lighting during periods of solar availability because of residential occupancy patterns. ALT 3 (shading) had a noticeable impact on reducing solar transmittance as expected but its detrimental effect on heating energy loads underscores the balance between advantageous thermal heat gain in the winter and unfavorable heat gain in the summer. Greater benefit from natural ventilation was expected based on preliminary analysis comparing unconditioned indoor space in the summer to naturally ventilated space. However, benefits of natural ventilation were not noticeable in the hourly design day charts, only in the energy consumption results. Natural ventilation can be a promising way to mitigate heat gain in the summer but further investigation is needed to understand how best to synchronize the mechanical systems. Energy consumption results showed the most efficient way to reduce energy use is to increase the building envelope U-value, including wall, roof, floor and glazing. Mixed-mode ventilation is also a good strategy to reduce the EUI. Natural ventilation is a sustainable way to cool down the house while mechanical ventilation could be a backup option when the outdoor air temperature is outside the comfort range. Shading devices and dimming control had little effect on HVAC energy consumption but dimming control could save energy on electricity consumption even though this is not counted for this analysis. For the further investigation, more energy efficient strategies could be experimented and simulated such as geothermal pump system and change of WWR ratio.
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1.0 Climate of Biloxi The building case our group was assigned is the Porchdog house located in Biloxi, Mississippi. The data below displays detailed weather info for the location of the house. Table 1.0.1 Weather Data
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Figure 1.0.2 Dry Bulb Temperature Distribution in Biloxi
Figure 1.0.3 Monthly Diurnal Averages
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1.1 Defining Thermal Zones The house is divided into (5) thermal zones as shown in Figure 1.1below. The entire first floor is a single thermal zone, including the double-height dining area on the west side of the house. The primary strategy for thermal zoning was to address thermal stratification between the floors aided by the open stair. The first and second floors also have different functions implying different schedules– overnight on the second floor and daytime on the first floor. While the team applied the same occupancy schedules to all zones, we thought it was important to zone the second floor bedrooms separately given their varying orientations and solar exposure too. Finally, the second floor bathroom and circulation space were also zoned separately as unconditioned spaces.
Figure 1.1
Figure 1.2
Zone 1 was used where the assignment asked to analyze only one thermal zone. See Figure 1.2 above.
1.2 Baseline Thermal Zone Properties The baseline zone properties are outlined in Tables 1.1 – 1.5 below. These parameters were applied to all simulation alternatives initially and any deviations from the baseline parameters are outlined in the following section (1.C). A custom residential occupancy schedule was developed to reflect a typical single-family home use pattern – heavier occupancy in the morning and evening with lighter occupancy during the middle of the day. The occupant load was determined conservatively assuming (2) people per bedroom – with a total of (4) people in the house. Custom materials and assemblies were generated to more accurately represent the intended/actual construction. The Archsim method for defining custom materials and assemblies is not clear about common assembly thermal characteristics such as outside and inside air films as well as air gaps within an assembly. Additionally, it wasn’t clear whether the layering order of an assembly was being considered (i.e. outside to inside or
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vice versa). To work around this uncertainty, air films and air gaps were omitted from the assembly definitions and in lieu of their presence, the insulation thickness was adjusted accordingly to match the U-values listed in Table 1.5 as closely as possible. Table 1.1
Table 1.2
Table 1.3
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Table 1.4
1.3 Alternative Properties In addition to the baseline, four simulation alternatives were analyzed for this report and are described below. Continuous dimming was used for ALT 2. - ALT 1: Envelope Assembly Improvements - ALT 2: Photo-Sensor Controlled Dimming - ALT 3: Local Shading - ALT 4: Mixed-Mode Natural Ventilation Figure 1.7 below describes the envelope modifications made for ALT 1. Target insulation Rvalues for ALT 1 were determined to exceed those prescribed in IECC 2018 (Table R402.1.2) for climate zone 5A. IECC prescribes R-20 for wood-framed walls and R-49 for ceiling but R-30 and R-60 were used respectively for ALT 1.
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Table 1.5
For ALT 3, local shading was added to the south and east-facing glazing as shown in Figure 1.3.
Figure 1.3
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A mixed-mode natural ventilation system was designed for ALT 4. Separate custom availability schedules were developed for heating, cooling, mechanical ventilation and natural ventilation so as to synchronize each mode and avoid overlapping schedules. Refer to Figures 1.9 â&#x20AC;&#x201C; 1.14 below for natural ventilation parameters and custom schedules.
Figure 1.9
The windows highlighted in Figure 1.9 above were considered the primary natural ventilation apertures for the house because of their high/low placement on the facades and thus were assigned a high operable area ratio of 75%. The remaining windows were assigned an operable area ratio of 25%. Table 1.6
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Figure 1.10
The CBE Thermal Comfort Tool was used to determine the adaptive comfort range for the cooling season during which natural ventilation could be utilized. Figure 1.10 above shows the adaptive comfort range of 24°C - 29°C superimposed on the hourly temperature chart to illustrate the effectiveness of natural ventilation for reducing the cooling load while achieving thermal comfort. The input parameters used to produce the adaptive comfort range are as follows: • Method: Adaptive • Operative Temperature: 26°C (cooling setpoint) • Prevailing Mean Outdoor Temp: 27.8°C The prevailing mean outdoor temperature was generated from the EPW weather file and computed as the monthly dry bulb temperature for the warmest month of the year.
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Figure 1.11
This analysis in Figure 1.11 was used as a preliminary study to assess the effectiveness of natural ventilation in this climate (zone 2A). Natural ventilation can be an effective strategy to mitigate cooling demand during the warmest parts of the year as indicated by the significant reduction in zone operative temperature when natural ventilation is utilized. Natural ventilation is particularly effective early and late in the day when the operative temperature falls within the comfort zone. The zone operative temperature still exceeds the comfort zone during the daytime, even with natural ventilation. Humidity is also an important factor to consider for this climate and the custom schedules developed below in Figures 1.12 â&#x20AC;&#x201C; 1.15 restrict the natural ventilation schedule so as not to invite very moist air into the house for the sake of sensible cooling.
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Figure 1.12 Natural Ventilation Availability Schedule
•
Availability Rules: <= 26°C AND > 20°C
Figure 1.13 Mechanical Ventilation Availability Schedule
•
Availability Rules: > 26°C OR <= 20°C
Figure 1.14 Cooling Availability Schedule
•
Availability Rules: > 26°C
Figure 1.15 Heating Availability Schedule
• Availability Rules: <= 20°C The custom schedules above were developed for a mixed-mode natural ventilation design alternative for thermal performance analysis. There are two pairs of complimentary schedules above: Figures 1.12 / 1.13 and 1.14 / 1.15. The heating and cooling availability schedules ensure that the house is conditioned during times when the outdoor dry bulb temperature is outside the dead band temperatures, while natural ventilation is defined to be in use when the outdoor DBT is within the dead band and RH is no more than 70%. Mechanical ventilation is available anytime the temperature is outside the dead band, which is the combination of both the heating and cooling availability schedules. The combination of each schedule ensures no overlap in natural/mechanical ventilation or heating/cooling schedules.
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2.1 Extreme Hot and Cold Week Temperature Analysis For this section of the report, we are assuming that heating and cooling, humidity controls and mechanical ventilation are turned off. This allows us to evaluate the design of the house and how it works in terms of dealing with extreme climatic heat and cold. By having a good design that remains within a comfortable temperature throughout the year, the need for other means of conditioning could be reduces, reducing the energy use of the building.
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Figure 2.1
Figure 2.2 During the extreme heat week, temperatures are warmer than comfortable and partially overlap with those of comfortable levels. The air tends to be very humid with a minimum of 50% and a maximum of 100%.
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Figure 2.3
Figure 2.4 During the extreme cold week, temperatures are far too low and not remotely close to comfortable levels. Also the air has some level of moisture in it.
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Figure 2.5
Figure 2.6
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The two charts above show the indoor hourly temperature fluctuations within the house in its current built condition, no alterations made. As shown above, the circulation, smaller bedroom and bathroom are all very linear and donâ&#x20AC;&#x2122;t deviate too much away from 38 degrees Celsius over the course of the extreme heat week and a small deviation from 8 degrees Celsius on December 23rd of the cold week. The master bedroom and first floor zone have larger floorplates and have façades facing multiple orientations, making them more likely to resemble the temperature shifts outside. This is clearly shown above as the orange (master bedroom) and grey (first floor zone) lines shift in temperature about the same time as the blue (Environment) temperature shifts.
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Figure 2.7
Figure 2.8
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The two charts above show the indoor hourly temperature fluctuations within the house with a change in the assembly materials. As shown above, the circulation, smaller bedroom and bathroom are all very linear and donâ&#x20AC;&#x2122;t deviate too much over the course of the extreme heat week like in the original design of the house, but there is a shift in the extreme cold week for these spaces. Unlike the original design of the house, these spaces are slightly warmer overall in the extreme cold week but also show and overall warming over the course of the week. The master bedroom and first floor zone still have temperature shifts similar to that of the original design, but these shifts have been significantly mitigated.
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Figure 2.9
Figure 2.10
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The two charts above show the indoor hourly temperature fluctuations within the house with the addition of dimming features. As shown above, the temperatures within the circulation, smaller bedroom and bathroom are all very linear and donâ&#x20AC;&#x2122;t deviate too much over the course of the extreme heat week like in the original design of the house. The master bedroom and first floor zone also still have temperature shifts similar to that of the original design. The reason for this is that controlling dimming impacts the lighting loads within the house. The problem with this is that this building is a residential building which means the loads are skin dominated and not internally dominated, meaning that the change in assembly has a far greater impact than something as miniscule as changing the operation of lights.
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Figure 2.11
Figure 2.12
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The two charts above show the indoor hourly temperature fluctuations within the house with the addition of shading devices. As shown above, the temperatures within all the zones are pretty much similar to that of the original. The reason for this is that the original design has small windows on the south faรงade meaning that the amount of heat coming in from these in the summer as a result of sun is not substantial. The change can barely be seen on the graph as this design change does nothing about the heat being transferred through the faรงade which is where the main problem lies.
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Figure 2.13
Figure 2.14
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The two charts above show the indoor hourly temperature fluctuations within the house with natural selection year round. As shown above, the temperatures within the circulation, smaller bedroom and bathroom actually deviate more over the course of the extreme heat week than it did in the original design of the house. This is because the temperature and humidity in this climate have very low comfort levels and by opening up the house to natural ventilation, these uncomfortable conditions are being allowed directly into the house. The master bedroom and first floor zone still have temperature shifts similar to that of the original design, but the performance of the house as a whole is actually in a more uncomfortable state than the original design.
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2.2 Annual Operative Temperature Analysis
Figure 2.15
Figure 2.16
The two psychrometric charts above shows the annual summary of comfort for Biloxi, Mississippi. The climate tends to be too hot or too cold to be comfortable. The winters tend to have a more evenly distribution of moisture while the summers tend to be very humid with high heat.
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2.3 Conclusion The design change that had the greatest impact on the thermal performance of the building without any means of conditioning is the alternative where the assembly changes. This had a major impact in the performance and temperature of the spaces as increasing the R value and reduced the amount of heat transfer between the indoors and outdoors. The temperatures in the master bedroom and first floor zone did fluctuate during large temperature shifts, but the amount of variation in indoor temperature was mitigated compared to the other strategies/leaving the building as is.
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2.4 Hourly Heat Gain/Loss: Occupants Occupant heating energy remained constant because the same occupancy schedule was used for all alternatives and for both winter and summer design days. The heating energy shown in Figure 2.3.1 below indicates that when the house is least occupied during the middle of the day, the heating energy is lowest. Because the climate in Biloxi, MS is somewhat balanced (HDD/CDD) and the occupant density is relatively low, the occupant heating energy generally doesnâ&#x20AC;&#x2122;t have an appreciable effect on heat gain/loss.
Figure 2.4.1
2.5 Hourly Heat Gain/Loss: Electric Light Energy Electric light energy was only effected by ALT 3 where photo-sensor controlled dimming was added to all thermal zones. The dimming controls were slightly more effective in the summer moths as opposed to the winter, probably due to the extended daylight hours. Electric light energy was unchanged for the other alternatives compared to the baseline because there was no change in how the lights were controlled. The custom occupancy schedule was used for lighting but moving forward, a separate schedule should be developed for lighting to reflect lights turned off overnight but because this change would also happen in the baseline, there would be no net change in electric light energy.
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Figure 2.3.2
Figure 2.3.3
2.6 Hourly Heat Gain/Loss: Electric Equipment Energy Electric equipment energy remained constant for all alternatives and the summer and winter design days because the custom occupancy schedule was used for equipment control.
Figure 2.3.4
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2.7 Hourly Heat Gain/Loss: Window Transmitted Solar Radiation ALT 1 (envelope) and ALT 3 (shading) had the biggest impact on window transmitted solar radiation. Referring to Figures 2.3.5 & 2.3.6 below, the most effective strategy for mitigating solar radiation gain & loss at the windows was the selection of low-e glazing. The coating effectively blocks excessive solar gain in July and January and reduces the peak transmitted solar radiation by 1/3 - from 6 kWh to 2 kWh. The east and west elevations of the house have a much higher WWR than the north and south. As a result, the hourly solar radiation curves take on an “M” shape with the two peaks aligning with the times of day where the east and west elevations are seeing the most solar exposure. Both in summer and winter, the window transmitted solar radiation reaches approx. 6 kWh during early morning and late afternoon. From Figures 2.3.5 & 2.3.6, we can also understand the effectiveness of the ALT 3 vertical shading as it reduces the transmitted solar radiation in summer and winter from 6 kWh to 4.5 kWh and 2 kWh respectively. Intuitively, the sun travels on a higher path in the summer and so east/west vertical shading is not as effective than when the sun travels on a more horizontal path across a façade. Also note that the ALT 3 curve is typically higher in the afternoon because, even with the existing shading overhang, the west façade still receives solar exposure when the sun is low.
Figure 2.3.5
Figure 2.3.6
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2.8 Hourly Heat Gain/Loss: Opaque Surface Conduction The baseline and ALT 4 (natural ventilation) simulation produced nearly identical opaque surface conduction results but there are several notable observations related to other alternatives. First, ALT 1 (envelope) showed the most significant reduction surface conduction in both seasons but most effectively in winter. For example, the peak opaque surface conduction reaches only 2 kWh in the summer but up to 4.5 kWh in the winter. The increased thermal resistance for the exterior wall, roof and floor surfaces outlined in Table 1.5 is effective for reducing conduction heat gain/loss. Second, ALT 3 (shading) reduced the morning peak conduction heat loss from 4.5 kWh to 3 kWh most likely an effect of reducing the solar heat gain in winter. By blocking sunlight in the morning, the thermal zone temperature delta between inside and outside surfaces is reduced. The less effective shading overhang on the west side of the house is ineffective at reducing winter solar heat gain and so the conduction loss remains the same as the baseline. Third, ALT 2 (dimming) produces a slight increase in peak heat gain/loss in the evening due (1 kWh in winter) to the more efficient management of electric lighting and consequently heat gain therefrom. Finally, the overall conduction profiles differ significantly between summer and winter. In summer, the flat heat gain conduction most of the day is attributed to the unit space being located on the first floor and buffered by the second floor spaces.
Figure 2.3.7
Figure 2.3.8
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2.9 Hourly Heat Gain/Loss: Infiltration Infiltration heat gain/loss was relatively unchanged across all alternatives. Generally, the summer infiltration gain spikes in early morning when the sun rises and then gradually dissipates beginning in the afternoon and finding the low shortly before sunrise. Winter infiltration is slightly steadier with the peak coinciding with the coldest part of the night, just before sunrise and the low point in the late afternoon. Since air movement is dependent, in part, on temperature differential, it makes sense that the winter infiltration high point coincides with the time of day most likely to have the greatest temperature differential between inside and outside. The ALT 4 (natural ventilation) schedule indicates a significant drop in infiltration heat gain energy in the overnight hours. This might be explained by the use of natural ventilation overnight essentially helping to cool the building in the summer. A curious observation is that the ALT 4 curve doesnâ&#x20AC;&#x2122;t otherwise deviate from the baseline. Further investigation is needed.
Figure 2.3.9
Figure 2.3.10
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2.10 Hourly Heat Gain/Loss: Total Ideal Loads Heating/Cooling Energy Biloxi is a relatively balanced climate but is more driven by cooling loads. ALT 1 (envelope) is most effective at mitigating cooling energy loads, cutting them in half during the daytime. ALT 3 (shading) had only a marginal effect on reducing cooling load and its effectiveness was limited to the morning. This can be related to the comments made in Chapter III, Section 6.1 regarding the vertical shading on the east faรงade. From the heating energy loads profile in Figure 2.3.12, it is evident that solar exposure in this climate can mitigate nearly all of the daytime heating energy loads. Again, the peak heating energy load occurs just before sunrise and is the lowest in the morning and afternoon when the east and west facades are experiencing the most solar exposure. In some ways, this chart is a mirror image of Figure 2.3.5, indicating that inverse relationship between heating energy loads and solar radiation. Similar to the cooling season, ALT 1 performs the best during the heating season as well, highlighting the effectiveness of increased thermal resistance. Finally, the effective east vertical shading in ALT 3 resulted in increased winter heating energy loads in the morning as the interior space no longer benefited from solar radiation.
Figure 3.11
Figure 3.12
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2.11 Hourly Heat Gain/Loss: Conclusion Different strategies were explored in each of the simulation alternatives for mitigating heat gain & loss at different times of day. Increasing the U-value of the exterior wall, roof and exterior floor assemblies in ALT 1 showed the most success in mitigating heating loads for most analysis metrics. An observable effect of photo-sensor dimming controls (ALT 2) was only apparent on the lighting energy loads. While dimming controls significantly reduced electric lighting energy during the daytime, its effectiveness is limited for residential application as the house is scheduled to use much less lighting during periods of solar availability because of residential occupancy patterns. ALT 3 (shading) had a noticeable impact on reducing solar transmittance as expected but its detrimental effect on heating energy loads underscores the balance between advantageous thermal heat gain in the winter and unfavorable heat gain in the summer. Greater benefit from natural ventilation was expected based on preliminary analysis done comparing unconditioned indoor space in the summer to naturally ventilated space. However, benefits of natural ventilation were not noticeable in the hourly design day charts. Natural ventilation could be a promising way to mitigate heat gain in the summer but further investigation is needed to understand how best to synchronize the mechanical systems.
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3.1 Heating & Cooling Energy Consumption: Baseline
Figure 4.A.1 Conditioning Settings and Occupancy Schedule
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Heating and Cooling set point temperature is 21°C and 26°C respectively. Heating, Cooling and Mechanical Ventilation also depends on occupancy schedule created. Infiltration rate is 0.33 ACH. Figure 4.A.1 shows the conditioning setting and occupancy schedule created. We also need to consider HVAC efficiency (Thermal Efficiency=0.8, Cooling COP=6). Annual Heating Annual Cooling EUI(kWh/m2) 120.9669/0.8=151 83.65788/6=13.94 Total EUI(kWh/m2) 164.64 Table 4.A.1 EUI of the Base case
Table 4.A.1 above shows the EUI for heating and cooling energy consumption of the baseline case.
Figure 4.A.2 Cumulative Heating & Cooling loads for individual zones
Figure 4.A.2 shows the mapping of the cumulative heating and cooling loads for each zone. Green means unconditioned zones and yellow means less heating and cooling loads. Master bedroom has the highest heating and cooling load because the thermal zone has very large window area comparing to the yellow thermal zone. The heating and cooling load of first floor zone is the second large one since the heat gain through window area is large although the shading device on west side.
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Figure 4.A.3 Monthly Heating & Cooling Energy Consumption
Figure 4.A.4 Monthly Heating & Cooling Energy Consumption
Figure 4.A.3 and Figure 4.A.4 show the monthly heating and cooling energy consumption for all thermal zones. The heating cooling energy consumption is
3.2 Heating & Cooling Energy Consumption: ALT1 â&#x20AC;&#x201C; Envelope Assembly Improvement Annual Heating Annual Cooling EUI(kWh/m2) 69.81635/0.8=87.28 52.18078/6=8.70 Total EUI(kWh/m2) 95.98 EUI Reduction -42% Table 4.B.1 EUI for the Alternative 1
Table 4.B.1 below shows the EUI for heating and cooling energy consumption of the baseline case. After improving U-value of wall, roof and exterior floor as well as adding low-e coating 124
for all glazing, the EUI reduction is significantly high â&#x20AC;&#x201D; 42%. Due to increased thermal insulation effect, heat gain and heat loss decreased from the envelope. Cooling energy reduced each month in winter and heating energy reduce each month in summer.
Figure 4.B.1 Cumulative Heating & Cooling loads for individual zones
In the Figure 4.B.1, we can see that the mapping of the cumulative heating and cooling loads are similar with the baseline case.
Figure 4.B.2 Monthly Heating & Cooling Energy Consumption
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Figure 4.B.3 Monthly Heating & Cooling Energy Consumption Baseline vs ALT1
Figure 4.B.4 Monthly Cooling Energy Consumption Baseline vs ALT1
From Figure 4.B.2, Figure 4.B.4 and Figure 4.B.3, both cooling and heating energy consumptions are reduced due to enhanced thermal mass property. Envelope thermal property had significant impact on heat transmission.
3.3 Heating & Cooling Energy Consumption: ALT2 â&#x20AC;&#x201C; Photo-Sensor Controlled Dimming Annual Heating Annual Cooling EUI(kWh/m2) 124.7206/0.8=156 78.36937/6=13 Total EUI(kWh/m2) 169 EUI Reduction +2.6% Table 4.C.1 EUI for the Alternative 2
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As Table 4.C.1 shows, EUI does not change much while heating EUI increases and cooling EUI decreases compared to baseline case after adding dimming control for electrical lighting appliances. The reason of increase of heating EUI is that electrical lighting appliances do emit heat waves in winter season and it helps heat the space. However, the dimming control will reduce the heat emission from the lighting devices. In summer, cooling demand is reduced due to less heat emission from the lighting devices. But this is a residential house where occupants will normally in home at late night or early evening where daylighting is not so strong and dimming control will not affect the heating and cooling consumption due to the occupancy schedule.
Figure 4.C.1 Mapping of cumulative heating & cooling energy consumption
From Figure 4.C.1, the mapping of the cumulative heating and cooling energy consumption is similar to baseline case.
Figure 4.C.2 Heating and Cooling Energy Consumption
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Figure 4.C.3 Monthly Heating Energy Consumption Comparison Baseline vs ALT2
Figure 4.C.4 Monthly Cooling Energy Consumption Baseline vs ALT2
From Figure 4.C.2, Figure 4.C.3 and Figure 4.C.4, the heating energy increases and cooling energy decreases when dimming control is on. And the cooling energy decreases a lot.
3.4 Heating & Cooling Energy Consumption: ALT3 â&#x20AC;&#x201C; Local Shading Annual Heating EUI(kWh/m2) 133.7449/0.8=167.18 Total EUI(kWh/m2) EUI Reduction
Annual Cooling 63.75625/6=10.63 177.81 +8%
Table 4.D.1 EUI for the Alternative 3
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Table 4.D.1 shows that EUI increases by 8% and it indicates that energy usage is not strongly related to solar radiation gain or loss. In alternative 4, vertical fins are added to the east glazing and overhang are added to the south and north glazing area as shown in Figure 4.D.1. The annual cumulative energy load mapping is similar to baseline case.
Figure 4.D.2 Mapping of the cumulative heating and cooling energy
Figure 4.D.3 Heating and Cooling Energy Consumption
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Figure 4.D.3 Monthly Heating Energy Comparison Baseline vs ALT3
Figure 4.D.4 Monthly Cooling Energy Comparison Baseline vs ALT3
From Figure 4.D.2, Figure 4.D.3 and Figure 4.D.4, the heating energy increases and cooling energy decreases when adding the shading devices. And the cooling energy decreases a lot that could compensate the increase of the heating energy annually. The reason why heating energy increases is that shading device blocked some direct solar radiation in daytime and thermal zones need more energy to be heated. Controversially, the room needs less energy to cool down the house.
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3.5 Heating & Cooling Energy Consumption: ALT4 – Mixed-Mode Natural Ventilation
Figure 4.E.1 Mixed Mode Natural Ventilation Setting (left) Figure 4.E.2 Different Schedules for Heating, Cooling, Mechanical Ventilation and Natural Ventilation (right)
In alternative 4, mixed mode ventilation system is adopted, and natural ventilation is adopted when the outdoor air temperature is between 21°C and 26°C. New ventilation schedules are created shown in Figure 4.E.2 for natural ventilation and mechanical ventilation. For natural ventilation, the house utilize the east and west glazing opening and the buoyance driven flow to cool down or heat up the house as indicate in Figure 4.E.1. Annual Heating EUI(kWh/m2) 111.2814/0.8=139 Total EUI(kWh/m2) EUI Reduction
Annual Cooling 56.51973=9.42 148.42 -10%
Table 4.E.1 EUI for ALT4
Table 4.E.1 shows that the EUI reduction is 10% because the house located at Biloxi that has a cooling dominate weather condition.
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Figure 4.E.3 Mapping of cumulative energy loads
The annual cumulative energy load mapping is different than baseline case. The yellow areaâ&#x20AC;&#x2122;s annual energy load is much smaller than master bedroomâ&#x20AC;&#x2122;s energy load comparing to other alternatives and baseline case.
Figure 4.E.4 Monthly Heating and Cooling Energy Consumption
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Figure 4.E.5 Monthly Heating Energy Comparison Baseline vs ALT4
Figure 4.E.6 Monthly Cooling Energy Comparison Baseline vs ALT4
From Figure 4.E.4, Figure 4.E.5 and Figure 4.E.6, monthly heating energy slightly decreases, and monthly cooling energy decreases when mix mode ventilation is adopted. The reason is that natural ventilation cools down the house when the outdoor air temperature is smaller than indoor set-point temperature where no energy is consumed for natural ventilation. But natural ventilation is not effective for monthly heating energy reduction.
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3.5 Heating & Cooling Energy Consumption: Conclusion Baseline
Heating (kWh) 151 Cooling (kWh) 13.94 Total EUI 164.94 (kWh/m2) EUI Change
ALT1Improved Assembly 87.28 8.7
ALT2-Dimming
ALT3-Shading
ALT4-Natural Ventilation
156 13
167.18 10.63
139 9.42
95.78
169
177.81
148.42
-41%
+2%
+8%
-10%
Table 2 EUI Comparison
To conclude, the most energy efficient design is to increase U value of building envelope including wall, roof, floor and glazing. Mix mode ventilation is also a good strategy to reduce EUI, natural ventilation is a sustainable way to cool down the house where mechanical ventilation could be a backup option when the outdoor air temperature is high. Shading devices and dimming control has little effect on HVAC energy consumption. And alternative 2 and alternative 3 even increased the energy consumption. But dimming control could save energy on electricity consumption which is not shown in heating and cooling energy part. For the further investigation, more energy efficient strategies could be experimented and simulated such as geothermal pump system and change of WWR ratio.
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IV. Power Generation 1.1 Photovoltaic Design In this section, a radiation calla dome was constructed by ladybug and the maximum radiation point is shown in the figure 2.2. For fixed PC panels, the best vertical/tilt angle is 30° and the best horizontal angle is 180°. And the maximum cumulative annual solar radiation at the optimal position is 1805.73kWh/m2.
Figure 1.1 Radiation calla dome Output
Figure 1.2 Radiation calla dome for Keesler
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1.2 Photovoltaic Orientation Analysis N W
E S
Our building on the site is facing the south so we are facing our panels south with an optimal angle of 22.5 degrees. With using the panel given to use and a 14.2% efficiency and with our location being in Mississippi with have a low tilt for the panels and high amount of sunlight through the year.
Figure 1.2 Tilt and Orientation Factor
This image is representing what is the optimal roof pitch for the panels in the location of the building. Also, adding the optimal azimuth angle for the panels on the roof which I said was 22.5 degrees.
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Figure 1.2.1 Tilt and Orientation Calculator Grasshopper Script
The image above is the grasshopper script to show the Tilt and Orientation calculation for the location of the building. The script shows all the optimal information to the panels for the roof.
1.3 PV Array System
Figure 1.2.2 PV Array
Here you can see the layout of the PV array system on the roof of the building. Here I placed the arrays away from the side of the roof and spread them apart from each other 1.2 m between. The PV array is 5 x 4 panles, making it a total of 20 panels. The are facing the south receiving as much sun as possible. With a efficinecy of 14.2 % and the panels are 31.9 inches wide abd 63.4 inches tall.
Figure 1.2.3 PV Array Model
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You can see here in in the figure that all of the panels are fit on th roof and are not getting blocked by the other panels or the landscape around the building.
1.4 PV Electrical Model (Ladybug)
Figure 1.2.5 Solar PV Model (Ladybug Script)
I have placed all 20 pv panels on the roof as one coninous array. I did run the simulation again and did get a total amount of AC of energy on the PV array which was 304 kWh.
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