While planning on getting a passive sustainable design for my home, I had to research the goals to know what I was getting. I found a few of the goals and the advantages of adopting a passive sustainable design for my home.
So, what is the goal of passive sustainable design? A passive sustainable design optimizes the location while achieving the right orientation for each building. This creates the right shading, and with the help of a thermal mass, it can take charge of the elements. During summer, the design brings in cool air, and during intense winters, it introduces the solar gains.
If you want to know about the passive sustainable design for your home, you should check it out. However, in this post, I would show you how to use this for even your commercial buildings.
The Goals of a Passive Sustainable Design
Passive sustainable design has a few goals it has set out to achieve when it comes to housing structures. This helps both you and the environment all at the same time. In this section, you would have a glimpse of what it entails to adopt a passive sustainable design.
Here are the goals of a Passive Sustainable Design:
- Getting a good location for your home
This is a crucial part of achieving a sustainable design in your home, as the location’s climate affects the whole process. For example, in Australia, every part of the eight varying climate zones has its peculiarities, which would determine how their design responds.
So, to achieve this goal, you would need to identify the climate in the zone and grasp and understand the principles of thermal comfort to get the design right. Some places have intense climate conditions, but passive sustainable design can handle all that with ease.
- Achieving the right orientation
This relates to the position in which the home is placed in the location or site. The orientation is used to fully optimize the climate’s characteristics, which includes the cooling breezes and sunlight. But, there are places where the living areas are made to face north, which helps maximize certain elements in the area.
It ensures that your home gains the right amount of sun exposure even in the winter seasons. This also ensures that in summer, the walls and windows receive enough coverage and shade. With this, there would be a great account of the seasonal variations that the sun may take and the angle and kind of winds in the area. In the longer scheme of things, this can help create a more comfortable home and makes it also cost-effective.
- Creating sufficient shading
Another important goal of passive sustainable design is achieving the right amount of shading. This is important because, with this, the house and other outdoor spaces would require it when dealing with intense summer temperatures. In the long run, this would promote comfort and conserve energy in the home.
There are a few things that could be used in achieving this. They are:
- Awnings.
- Shutters.
- Eaves.
- Pergolas.
- Plants.
With these few accessories, you can block up to ninety percent of the heat generated from direct contact with sunlight. The good thing is, it can be as much heat as you would get with a single radiator bar over one square meter in your area.
Yet, you mustn’t create a blockage that would affect the winter sun too. Winter comes with a cold breeze, and you would need every help you can get, even if it is from the sun. So, I would suggest that you calculate the sun angles in your location and then create a respective shading amount.
- Maximizing the building layout
When developing a sustainable passive design, the entire building layout’s entirety has to provide maximum comfort while in use. This has to do with areas like the rooms as well as the outdoor spaces around the site. This simply entails that the main living areas, like the dining, family room, and living room, should face the sun all day.
There must be some sort of horizontal shading that you could rely upon when dealing with intense summers to achieve this. But, it should still have a promising solar gain during winter. This is majorly guaranteed when the area is facing the north in the Southern Hemisphere or south in the Northern Hemisphere.
Moving on, when it comes to your kitchen areas or where you have your breakfast, it is only ideal that they are facing the east region. The goal of this is to provide sufficient morning light that you would love while ensuring solar gains at the same time. It also feeds you with cool afternoons that comes in handy when you need to prepare your meals.
For rooms that are placed to face the west, the goal is to have good afternoon daylight. Still, the downside is that during intense summers, these areas are prone to overheating.
Those areas facing the south on the Southern Hemisphere or the north in the Northern Hemisphere are originally designed for minimal or no heat gain and still offer substandard natural light.
- Initiating a thermal mass
Regarding thermal mass, this is solely the ability for a component to take in and store heat energy. When altering the temperature of high-density materials like bricks, concrete, tiles, etc. a commendable mass of heat energy is required. This is what is referred to as thermal mass in passive sustainable design. For low weight materials like timber and co, a low thermal mass is required.
When the thermal mass is adequately utilized, the indoor temperatures would be affected by averaging even the most intense temperatures. This has proven useful when there is a bit of disparity between the day and night temperatures that exist outside.
However, it is equally important that you note that the thermal mass does not substitute for insulation. Instead, all it does for you is to contain and then redistribute the heat at a more friendly temperature. Insulation on its end totally prevents the inflow or outflow of heat in the building.
For example, building a home in Texas with a myriad of high plains can host a wide range of temperature altercation. Here, thermal mass sets in and regulates this abnormally, making it more comfortable to live in such a location.
- Free flow of natural ventilation
Passive sustainable design is one that tries to take advantage of the natural forces of the wind to feed the building with sufficient fresh air. Consequentially, fresh air helps in eliminating a few unwanted things in the building. They may include any foul smell in the building, provide the required oxygen for perspiration, and improve thermal comfort.
Depending on the building in question, the design and approach to natural ventilation would take a distinct turn. There are a few things that could affect this, and they are:
- The local climate in the area.
- The level of interior spaces in the building.
- The size of the whole building.
- How is each opening placed in the building?
With these taken into consideration, you can have the right amount of fresh air coming into the building per time.
- Optimizing the window design
Originally, windows and doors are tasked with providing light, clean air, and the right outdoor view. Yet they could pose a problem in the house, as they most times serve as a source of heat loss during cold winters and unwarranted heat gain during intense summers.
It is estimated that when a window or any opening as such is not well optimized, that could pose a great problem. It could allow you to lose as much as forty percent of the home’s heating energy. When it regards heat gain, it causes about eighty-seven percent of heat loss during winters.
Therefore, with this sustainable design, the window’s thermal performance is optimized for comfort. With a newly installed smart window design, you would be cutting down on the gas your greenhouse emits as well as your regular energy costs.
But, three major things are considered when designing an optimized passive window. They are:
- Location of the building.
- Size of the building.
- Glazing systems.
Once you can have all of this in place, then you can have an optimized window design for your home. I would suggest that you take note of these and create the right condition in your home.
- Getting the Building Insulation
Since insulation serves as a barricade against heat flow, then it is a crucial part of your passive design. The aim of this is to keep the home warm and protect from the cold breeze it comes with. It also serves as an effective way of keeping the place cool when it’s summertime.
The level and amount of insulation needed in your residence depend on your location’s climatic condition. What you also aim to achieve with insulation also is pivotal to selecting the level of insulation.
You may have to strongly consider the seasons and how intense they can be when it comes to temperature variation. If you necessarily have to keep heat out, you may need less if the location is prone to hot temperatures. If the area is naturally hot then, then you may need less insulation and so on.
It also comes in useful when you require help taken care of your moisture problem or just need soundproofing. But all of these are attained when you combine both insulations as well as other passive design options to get optimum results.
For example, if the building is not adequately sheltered, then insulation becomes more of a problem. When heat is built up and held in the house by insulation, then it could cause the ‘oven effect.’ This is when the room is stuffy as a result of excess heat.
- Making use of the skylights
Even in passive design, the skylights are a great source of inspiration when handling the building. Over time, it has served as a reliable source of natural light and when used in place of windows. They are estimated to take in up to three times the natural light of regular vertical windows and yet created a better source of natural ventilation.
Choosing to use skylights is a reasonable alternative when you have to deal with a restricted size of windows. This could be the case when you are trying to keep the whole place private, so you would just opt for skylights instead.
Aside from how effective the skylights can be, it is also aesthetically pleasing as it gives the building a different look. The goal of passive designs is to create an effective yet comfortable system that would serve a purpose in your home at a reduced cost.
How Does Passive Sustainable Design Work In a Local Area?
A passive sustainable design responds to the local area climate and the site’s condition to provide comfort to the user. It also takes charge of the health condition with the help of optimal energy use.
The passive sustainable design achieves this with the help of free but renewable energy sources like the wind and the sun. They consequentially provide the user with household cooling, heating, ventilation, and even lighting. This takes out the need for mechanical cooling or heating systems.
Passive systems design can optimize any form of discrepancy in the building temperature. It can also improve the indoor air quality and make the home more moisture-free and comfortable to live in. The design reduces energy usage and the impact of this energy on the environment as a whole, like greenhouse gas emissions.
For places like New Zealand, a well-optimized passive solar home design can produce a comfortable internal temperature between 18°C and 25°C. All of this is done while the cost of running is brought to the barest minimum all through the year.
Even though there are restricted amounts of information pertaining to the benefits of a resale when it comes to such houses, there is undeniable evidence that internationally these kinds of better performing houses go for only a premium price and even sell a lot faster than regular buildings.
Statistically, some studies show that homes built with a passive sustainable design or green labels go for as much as an extra four to ten percent. This is a rough estimate, but it shows how well they are valued in the market.
Over the last decade and even more, the interest in passive designs has skyrocketed as a result of a movement. This movement aims at achieving a more resource-efficient building that is good for the environment and yet more comfortable for use. This is one good case of a win-win situation when it comes to housing.
Strategies to be used in the Passive Sustainable Design
To achieve the goals of Passive Sustainable Design, some strategies can be followed. With these strategies, you can finally have a functional Passive Sustainable Design in your building. These strategies are important, and they should be considered if you want to have a passive design in your home.
So, check them out:
Passive Heating:
A great strategy is to capitalize on solar radiation and retain the internal heat gains to create a passive sustainable system. There are only a few elements that are required to perform this function. Once they are put into consideration, then you can make use of this strategy in your building.
They are:
- Building shape
- Orientation
- Double facades and Buffer spaces
- Operable external shading
- Accurate space planning
- High-performance windows (clear, Low-E)
- Low window to wall area ratio (N/E)
- High window to wall area ratio (S/W)
- High-performance insulation
- Minimized infiltration
- Mixed-mode heat recovery ventilation (HRV)
- Thermal mass
With this, you can make optimum use of passive heating in your home.
Passive ventilation system:
This strategy makes use of the natural flow of air in and out of the location and building. It brings the outdoor air into the indoor space and reduces the cost of ventilation. Buoyancy and wind triggered by a difference in the air temperature can help create varying air pressure all through the occupied spaces.
This simply means you can use fresh air in place of venting systems.
For you to achieve this, you would need to get a few natural ventilation elements. The following are, therefore, advisable to achieve this:
- Operatable windows
- Double facades and Buffer spaces.
- Proper orientation.
- Conscious architectural features
- Openings to corridors and between otherwise different spaces.
- Central lobbies and atria.
- Wind towers
Passive Cooling System:
These systems help the building stop overheating by shielding solar gains and taking out internal heat gains. This strategy can be used by storing excess heat in the thermal mass and makes use of cooling outdoor air for ventilation.
Here the sun is optimized during the season of intense winter cold conditions. The wind is also made use to cool off the space when there are intense summer heats.
There are a few elements that would help this strategy, and they include the following:
- Thermal mass
- Fixed/operable external shading
- Earth-tempering ducts
- Nocturnal cooling
- Stacked windows
- Passive ventilation
- Passive evaporative cooling
With the help of a nocturnal cooling system, an overnight natural ventilation system to take out heat accumulated in your home during the day. This helps you in flushing out the air while cooling the warm building mass or building.
Daylighting:
This strategy makes use of the natural daylight in your location to light up the building. With this, there would be a reduction in the need for electric lighting or any artificial source of light. The idea of daylighting is to create enough light in the room with the sunlight. For example, the house can be facing the north in Australia because that is where the sun comes in from during the day.
So, with this daylighting strategy, you could also reduce the cost of using artificial lighting conditions in your home.
When it comes to the elements required, there are few needed.
They include:
- Space planning
- High ceilings paired with upright windows
- Light shelves
- Clerestories
- Skylights and light tubes
- Interior surface colors and finishes
- Window size and placement (window to wall area ratio)
Applying the strategies
Though the Passive Sustainable Design has been most talked about to work for a residential building over the years, it has become more than that. They now function for both residential and commercial buildings, and here is how they do that.
Going commercial:
Commercial buildings are designed differently from the regular buildings that are for residential purposes. They would require a higher level of internal heat gains from the lighting down to the equipment, and the vents take more than use and a different occupancy trend.
When it has to do with commercial buildings, there is a lot to benefit from passive cooling. However, if you consider a climate like Vancouver, the design must balance the cooling system and the heating systems.
There are specific approaches that are you would need to apply when going commercial, and they include:
- The careful but detailed construction of high performing insulation systems. This is applicable in the envelope with a reduced amount of thermal bridging, which consists of roofs and walls.
- They could also maximize the solar gain control system by getting high performing windows with minimal shading coefficient. It could be tinted or reflective and require high performing windows with a minimal level of e-coating in combination with functional external shading. This would help maximize the solar gains during winters and shield the solar gains during hot summers.
- Here the window to wall area ratio is reduced to less than fifty percent.
- There is also a need for double facades with functional shading elements and working windows to function as thermal buffer spaces. It could also pre-heat the air in the ventilator for winter seasons and well as block any unwarranted solar gain. In the end, it creates natural ventilation during the summer seasons.
- Creating a building shape and mass that would help foster natural ventilation as well as easy daylighting. This is ideally done with ventilation towers and central atria.
- Using a thermal mass on the inside of the insulation could be placed in various areas of the building. You could place them on the floors, external walls, and any adjoin walls like the party units.
- They also need a passive cooling system like the nocturnal ventilation system. This would help in pre-cooling the building when the summer heat comes by maximizing the ventilation air intake. These are located in cool areas in the building and then distributed to other parts with earth tubes’ help.
- Lastly, you can go commercial by making use of air and moisture tight envelopes.
Going Residential:
In some markets like the Vancouver market, many residential buildings are constructed of high and medium-rise towers. These residential homes have a night-time occupancy level and do not offer equal heat gains except with intermittent cooking. This would contribute to heating-dominant residential energy in a place like Vancouver.
The specific approach for the total energy performance of the residential buildings entails:
- A carefully laid out and detailed high performing insulation in the envelope creates a minimal thermal mass level. This would cover as much as the exterior walls and roofs in your home.
- It creates a clear and low energy consuming system through the use of high performing windows. It also combines a functional external shading system to shield the solar gains during intense summer gains. It also takes in solar gains when you are battling intense winter seasons.
- Uncontrolled and controlled buffer spaces that are not occupied frequently cover the space’s perimeter. This is combined with functional windows that create natural ventilation from the outside to even interior spaces when you need it to be.
- Using a thermal mass on the inside of the insulation could be located in various areas. It would go on the floors, external walls, and adjoining walls like the party walls.
- It makes use of a simple and more mobile form.
- Making use of air and moisture tight envelopes.
- You could also use mixed-mode ventilation with the help of HRV during winter seasons and the passive ventilation all through the remaining year.
It is important to note that any residential building that has a window-to-wall ratio that is way more than fifty percent would find it difficult to achieve high energy performance.
With all these considered, you can select the right passive sustainable design for both a residential building and commercial building.
Final words
The passive sustainable design is an option available for your residential buildings. It offers so much in terms of getting the environmental properties of your location optimized. With this optimization, you can have more cost-efficient and operable houses, yet your comfort is not compromised.
Good news, they don’t only function for residential buildings as it has been over the years. With research and detailing, you can now have a passive sustainable design that functions in your commercial buildings. Offices, malls, and others in this category can now run at a lower cost than regular.
