Passive Architectural Design
Passive design features are inherent to the architectural design, material choice, and configuration of the building. Passive design should maximize the positive benefits of the local climate (for example, capturing the sunlight for natural lighting and heating) and minimize the negative effects such as adding loads to the amount of cooling needed.
BUILDING MASSING AND ORIENTATION
"Massing" refers to the overall shape of the building (tall or short, long and thin, more cutouts or more solid. Successful massing uses the general shape and size of the building to maximize free energy from the environment (i.e. the sun and wind) and minimize the amount of energy loads that will require more active design systems.
The orientation of the building along with the design features that relate to the sun path can have a significant impact on the building performance as well as the comfort of its users. Orientation is simply what sides of the building are facing what degree of cardinal direction. Thinking about which directions the windows face on the building will admit sunlight when it is beneficial but block it when it is not desired or needed.
Considering both massing and orientation together, the design can determine how much surface area is exposed to sunlight at particular times of the day. Successful applications of passive design start with decisions made early on in the design process.
PASSIVE COOLING
Passive cooling design include strategies like natural ventilation, air cooling, and shades to reduce the need for mechanical cooling on hot days as well as maintain thermal comfort.
Natural ventilation takes advantage of outside air movement and pressure differences to provide movement of fresh air without the use of mechanical fans. The simple act of opening a window can provide immediate cooling effects. Placing an operable window at a higher point on the wall allows hot air to be pushed out.
Sometimes a space can get too hot for natural ventilation to have an impact on the indoor air comfort. A thermal mass can help passively regulate and maintain thermal comfort in these instances. "Night purge ventilation" keeps windows and other passive ventilation means closed during the day and then open at night to flush the heat out. Instead, during the day, the thermal mass absorbs and stores the incoming heat throughout the course of the day and at night slowly radiates its heat into the space to keep temperature consistent and to avoid large temperature swings that would strain the use of mechanical heating and cooling systems.
BUILDING MASSING AND ORIENTATION
"Massing" refers to the overall shape of the building (tall or short, long and thin, more cutouts or more solid. Successful massing uses the general shape and size of the building to maximize free energy from the environment (i.e. the sun and wind) and minimize the amount of energy loads that will require more active design systems.
The orientation of the building along with the design features that relate to the sun path can have a significant impact on the building performance as well as the comfort of its users. Orientation is simply what sides of the building are facing what degree of cardinal direction. Thinking about which directions the windows face on the building will admit sunlight when it is beneficial but block it when it is not desired or needed.
Considering both massing and orientation together, the design can determine how much surface area is exposed to sunlight at particular times of the day. Successful applications of passive design start with decisions made early on in the design process.
PASSIVE COOLING
Passive cooling design include strategies like natural ventilation, air cooling, and shades to reduce the need for mechanical cooling on hot days as well as maintain thermal comfort.
Natural ventilation takes advantage of outside air movement and pressure differences to provide movement of fresh air without the use of mechanical fans. The simple act of opening a window can provide immediate cooling effects. Placing an operable window at a higher point on the wall allows hot air to be pushed out.
Sometimes a space can get too hot for natural ventilation to have an impact on the indoor air comfort. A thermal mass can help passively regulate and maintain thermal comfort in these instances. "Night purge ventilation" keeps windows and other passive ventilation means closed during the day and then open at night to flush the heat out. Instead, during the day, the thermal mass absorbs and stores the incoming heat throughout the course of the day and at night slowly radiates its heat into the space to keep temperature consistent and to avoid large temperature swings that would strain the use of mechanical heating and cooling systems.
Words of Advice from an Architect: Liz Cordill
Liz Ann Cordill is a registered architect and is LEED certified. LEED (Leaders in Energy and Environmental Design) stands for green building leadership. When approaching her with our goals and design intent, she gave us some insight on the practicality of designing sustainably.
"There are so many high end and new technologies that are 'green' and 'sustainable' but you also have to consider how reasonable it is to apply these expensive new inventions in practice. While everyone wants to go green, do they really want to spend hundreds or thousands of dollars to do it?"
Cordill guided us in a more refined direction and suggested we think modularly. Modules can easily be reassembled, transported, and reused. Items and materials are sold in modules, so if we could think about the practicality of using certain materials that would be a good start for us. She also gave us projects to look at to learn and be inspire. Low cost living and sustainable housing have great potential of going hand in hand.
Our Design: An Energy Conscious Living Unit
![Picture](/uploads/4/3/9/2/43920657/1418261503.png)
We felt the amount of space people live in now is largely unnecessary which is not sustainable in its own way. Ultimately, the overall dimensions of 25'x25' is intended for 2 people to live comfortably within their means. Within these dimensions we can fit a full bathroom, a small kitchen, 2 desks, 2 beds, a built in storage unit with 2 closets, as well as a porch along the south exterior.
For our living unit to be as energy efficient as possible, it had to begin with the incorporation of passive design. The orientation of the living unit puts the solid wall facing West. In Houston, the West side receives the most sunlight and therefore has the most heat gain. Putting a completely solid wall on this side eliminates any excess and unnecessary heat from coming into the living space from the West. The South and East facades are completely made of glass. This is initially a design aesthetic decision, but the incorporation of other passive structures balances out the concern of how much sunlight is coming in. The south windows are actually inset 4 feet to create a porch at the entrance as well as to allow the roof to overhang. An overhang on the south facade is optimal for Houston because this will provide shade from the high summer sun but let in heat when the winter sun is low in the sky and when more heat is desired. There are operable windows on the south facade and the north facade so that, if needed, air can naturally ventilate through the living space. Horizontal louvers are also incorporated into the design to provide not only extra shading for the south and east sides, but also privacy to the bedroom located at the east of the living unit.
For our living unit to be as energy efficient as possible, it had to begin with the incorporation of passive design. The orientation of the living unit puts the solid wall facing West. In Houston, the West side receives the most sunlight and therefore has the most heat gain. Putting a completely solid wall on this side eliminates any excess and unnecessary heat from coming into the living space from the West. The South and East facades are completely made of glass. This is initially a design aesthetic decision, but the incorporation of other passive structures balances out the concern of how much sunlight is coming in. The south windows are actually inset 4 feet to create a porch at the entrance as well as to allow the roof to overhang. An overhang on the south facade is optimal for Houston because this will provide shade from the high summer sun but let in heat when the winter sun is low in the sky and when more heat is desired. There are operable windows on the south facade and the north facade so that, if needed, air can naturally ventilate through the living space. Horizontal louvers are also incorporated into the design to provide not only extra shading for the south and east sides, but also privacy to the bedroom located at the east of the living unit.
Sources:
http://bimcurriculum.autodesk.com/lesson/lesson-1-passive-design
http://sustainabilityworkshop.autodesk.com/buildings/building-massing-orientation
http://sustainabilityworkshop.autodesk.com/buildings/apertures-cooling
http://sustainabilityworkshop.autodesk.com/buildings/night-purge-ventilation
http://www.usgbc.org/leed
Discussion with Liz Cordill
Model built by Christine Nguyen and Tonya Sok
Sketches and drawings made my Christine Nguyen and Tonya Sok
http://bimcurriculum.autodesk.com/lesson/lesson-1-passive-design
http://sustainabilityworkshop.autodesk.com/buildings/building-massing-orientation
http://sustainabilityworkshop.autodesk.com/buildings/apertures-cooling
http://sustainabilityworkshop.autodesk.com/buildings/night-purge-ventilation
http://www.usgbc.org/leed
Discussion with Liz Cordill
Model built by Christine Nguyen and Tonya Sok
Sketches and drawings made my Christine Nguyen and Tonya Sok