I'm trying to learn about shading buildings, and in the books I've read, they always talk about the North, West, East and South side but never the Northwest, Northeast, Southwest, Southeast side.
Climate is tropical savanna
Latitude is 14
What i know so far
North/South horizontal shading device
East/West Block if possible, Vertical + horizontal shading device
I like to ask for some advice on what to do with these sides (NW,NE,SE,SW)?
Do i based this on the North/South or the East/West?
TIA!
go do it
Feb 20, 17 2:39 am
what does tia mean?
pleiades
Feb 20, 17 3:00 am
hi go do it, TIA means thanks in advance
Volunteer
Feb 21, 17 8:17 am
Well, in the summertime the sun sets in the northwest after reaching a high azimuth to the south at noon, and in the winter in the southwest after reaching a low azimuth to the south at noon, but the variations at 14 degrees of latitude are not all that great. The most critical need for shade would be in the summer, when the sun is at noon (due south but high in the sky) until about 4 or 5 pm when it is still southwest or even due west and lower in the sky. Typically you would not be that concerned with a low setting summertime sun finally slipping below the horizon to the northwest, and I don't think you would be that concerned with a morning sun at least from a prospect of the building becoming uncomfortably hot.
Wood Guy
Feb 21, 17 9:35 am
Pleiades, do you understand the path the sun takes as it moves through the sky? I ask honestly; many people do not really understand how this works.
I would treat the SE and SW the same as a south-facing wall, with a horizontal shading device sized to limit insolation during the summer months. Vertical shading devices (typically sliding screens) also work but are not as common as awning structures (e.g., brise soleils).
As Volunteer implied, the NE and NW sun is low on the horizon and its rays have to travel through more atmosphere, so they are not as strong as the mid-day sun.
If the building is over-glazed you can still get morning overheating with NE, E or SE-facing glass, and you can definitely get a blast of unwanted heat on any west-facing glass. Because the sun is low in the sky on the east and west, overhead (horizontal) screening devices don't work unless they are really deep, like a porch, so for low-energy buildings it's important to not overglaze the east and west.
randomised
Feb 21, 17 11:24 am
Just to get a feel of the sun path, check out SunCalc for your location and fiddle with the times, my guess is Manila Philippines...
pleiades
Feb 21, 17 10:05 pm
@ Volunteer
Thank you for your help! sorry for beginner questions.
How did you know the variations at 14 degrees are not great?
"The most critical need for shade would be in the summer, when the sun is at noon (due south but high in the sky) until about 4 or 5 pm when it is still southwest or even due west and lower in the sky"
That sentence is amazing! can you tell me how to do something that?
@ Wood Guy I have some idea, but not sure if its correct though, What i know so far , please do correct me if I'm wrong,
On the northern hemisphere,
Dec 21 Winter Solstice (Winter) - The sun path is on the south, sunrise at SE, sunset at SW Mar 21 Equinox - The sun path is still on the south going to the north, sunrise at E, sunset at W June 21 Summer Solstice (Summertime) - The sun path is on the north, sunrise at NE, sunset at NW Sept 21 Equinox - The sun path has gone back down to the south, sunrise at E, sunset at W
Is that what you meant with the question "do you understand the path the sun takes as it moves through the sky?"
Thanks for the advice, I will use horizontal shading device for the SE,SW, and limit glazing on the NE,E,SE,W sides
A little off topic, I dont understant these brise soleils, in the pictures with brise soleils, I can see a combination of vertical/horizontal louvers/overhang, it seems like an egg-crate shading, how can you tell if its a brise soleils?
@ randomised
Thank you for the Suncalc app, you are correct in the location Just a question in the suncalc app, is the yellow part in between the white part the heated are of the sun?
@ all sorry for the beginner questions, I'm trying to self-learn this because I think this is really important. do you have any recommended books? especially for tropical savanna building design or general knowledge. or any software to understand this much better.
TIA all!
randomised
Feb 22, 17 6:40 am
The yellow part is just an indication of the sun path I suppose, giving it the idea of height on a 2-dimensional map.
Wood Guy
Feb 22, 17 9:56 am
Pleiades, that is correct. The closer you are to the equator, the less difference there is in the sun's position seasonally--both in terms of how far to the north or south of true east or west it rises and sets, and how high the sun is above the horizon. You might find this page helpful: http://www.builditsolar.com/SiteSurvey/site_survey.htm. There is a lot of great information on that site, which has been around a long time.
I see what you mean about searching for brise soleil images. This is what I meant, and how I do horizontal shading devices.
JLC-1
Feb 22, 17 10:24 am
that's a beautiful house, should have shopped the ac unit out of the picture.
Wood Guy
Feb 22, 17 10:32 am
Thanks; I wasn't the architect, this was: http://www.johngordonarch.com/houses-1/. I worked for the Passive House panelizing company that built it (http://www.ecocor.us/projects/eastview-passivhaus). (I was involved in all of the detailing, including the brise soleils.) Nothing wrong with a nicely placed, high performance air source heat pump, in my opinion, but I agree it would look cleaner without it. It's on the side of a mountain overlooking the ocean, far from any other houses, so nobody will actually see the outdoor unit.
JLC-1
Feb 22, 17 10:38 am
I was going to ask how that roof drained, but the picture just answered it.
pleiades
Feb 22, 17 8:51 pm
@ randomised
Thanks for the info, what do you usually use the solar path for?
@ Wood Guy
Thank you, but I think I still don't fully understand the sun path,
The part "how high the sun is above the horizon" is that the altitude of the sun?
I'm going to study the link, thank you for that, I have to make some time reading it slowly, some are new to me. can I contact you privately if I can't understand something?
Does the term brise soleil can be any shading device like the overhang in your picture?
Thats a very modern building, I like those type of design, the contrast of the wood overhang and the wood porch detail to the white panelized wall is good.
Is the picture showing the south side of the building? for solar heating i guess.
Thats the first time I saw a heat pump, It looks like a split type air condition unit.
TIA all!
randomised
Feb 23, 17 3:13 am
I don't consciously use sun path studies, I mostly apply the principles subconsciously.
pleiades
Feb 23, 17 4:47 am
can you share any principles you always use?
randomised
Feb 23, 17 9:30 am
Knowing where the sun rises, how it travels and where it sets, that's all basically.
Very easy to double check in programs like sketchup, if you give the project the correct geolocation you can do simple tests adjusting date and time of your project and see the shadows etc.
pleiades
Feb 23, 17 11:22 pm
Thank you for the tip, I will learn how to do that in sketchup.
Volunteer
Feb 23, 17 8:57 am
Pleiades, I think you are getting the compass points for the rising and setting points of the sun confused with the angular position of the sun at midday. At noon on the summer solstice in Manila the sun is at 81 degrees (with 90 degrees being straight up) and in winter it is at 52 degrees. Face south and put your arm almost straight up for a good approximation of the summer sun height on noon on the summer solstice, and a little more than 45 degrees from the horizon for the position of the sun at noon on the winter solstice position.
pleiades
Feb 23, 17 11:23 pm
yes, i still don't fully understand this,
I checked your quote " At noon on the summer solstice in Manila the sun is at 81 degrees (with 90 degrees being straight up) and in winter it is at 52 degrees." and you're spot on!
With the question How did you know the variations at 14 degrees are not great?
The answer is the variation in the altitude is smallI took all the altitude at 12:00PM Day 21st
Month | Altitude
1 | 55.19
2 | 64
3 | 75.67
4 | 87
5 | 84
6 | 81
7 | 84
8 | 87.48
9 | 75
10 | 64
11 | 55
12 | 51
How do you use the altitude in your design?
Face south and put your arm almost straight up for a good approximation of the summer sun height on noon on the summer solstice, and a little more than 45 degrees from the horizon for the position of the sun at noon on the winter solstice position.
I will test that out later!
Wood Guy
Feb 23, 17 9:44 am
Pleiades,
The part "how high the sun is above the horizon" is that the altitude of the sun?
Yes, that is one correct term; another is elevation angle. Both are confusing because altitude and elevation have other meanings. At mid-day, from where you're standing, if you face the sun and draw a line to the horizon, and another line to the sun, the angle between those lines is the solar altitude or elevation angle. At the summer solstice, the angle will be greatest, and at the winter solstice the angle will be least. Where I am at 44° latitude, the angles are 69° in summer and 22° in winter--quite a difference! Where you are the numbers will be closer together, and closer to 90°.
I'm going to study the link, thank you for that, I have to make some time reading it slowly, some are new to me. can I contact you privately if I can't understand something?
Yes, you can contact me through my profile here, but the discussion may interest others so I would suggest keeping it public. There's no shame in asking questions if you don't understand something. Many architects do not fully understand the significance of solar orientation and the sun's path through the sky. I work in a cold climate and primarily design homes that use 10-20% as much energy as a standard, code-built home, so I have to pay close attention to such details.
Does the term brise soleil can be any shading device like the overhang in your picture?
Yes, brise soleil is just French for sun breaker. There are other terms that serve the same purpose. Awning roof, awning structure, pent roof, sun baffle, or sun-shading-device can all be used for the horizontal structure. Vertical screens are often moveable and called shutters or sliding shutters.
Thats a very modern building, I like those type of design, the contrast of the wood overhang and the wood porch detail to the white panelized wall is good.
Yes, the original design was more traditional but the client came to us to use our system of building super energy efficient homes with a relatively low budget. The budget dictated removing all ornament, which we did in conjunction with the architect. In normal construction roof overhangs serve a purpose, but our system is designed so they are not necessary.
Is the picture showing the south side of the building? for solar heating i guess.
The long side of the building actually faces east-south-east to best fit its location. There is more glazing on the east than ideal for lowest energy use, but with the views from the site we had to make that sacrifice. It's not certified but meets the requirements for the international Passive House association for low-energy buildings. With those houses you don't want too much glazing on the south because it will overheat, even in a cold climate. On the coldest day of the year, the house pictured can be heated comfortably with a standard hair dryer (or other 1500 watt device.) If the heat was never turned on, even in our climate which can reach -20°F (~-30°C) the house will never drop below 50°F (10°C).
Thats the first time I saw a heat pump, It looks like a split type air condition unit.
Yes, the technology is the same, but essentially run in reverse it functions as a super efficient heat source. Efficiency of electric heating units is measured in COP (coefficient of performance). These units have a COP of about 3.0, meaning for every unit of energy put in, you get three units of energy out. The COP drops somewhat in very cold weather but remains much more efficient than other heat sources.
pleiades
Feb 23, 17 11:21 pm
At the summer solstice, the angle will be greatest, and at the winter solstice the angle will be least. Where I am at 44° latitude, the angles are 69° in summer and 22° in winter--quite a difference! Where you are the numbers will be closer together, and closer to 90°.
I see now, when your farther away the equator, the sun's altitude variation is greater.
Yes, you can contact me through my profile here, but the discussion may interest others so I would suggest keeping it public.
Thank you very much sir Wood Guy,
Many architects do not fully understand the significance of solar orientation and the sun's path through the sky. I work in a cold climate and primarily design homes that use 10-20% as much energy as a standard, code-built home, so I have to pay close attention to such details
I really thought architecture is just about the built forms based on what i see on the internet, did not know its actually part of earth's processes.
Thats impressive, you must know a lot about the wind, heat flows, pollutions. I want to know what you know. do you have any recommended books to learn it from?
Yes, brise soleil is just French for sun breaker. There are other terms that serve the same purpose. Awning roof, awning structure, pent roof, sun baffle, or sun-shading-device can all be used for the horizontal structure. Vertical screens are often moveable and called shutters or sliding shutters.
I see, I will use brise soleil in describing shading device now, it sounds exquisite.
Yes, the original design was more traditional but the client came to us to use our system of building super energy efficient homes with a relatively low budget. The budget dictated removing all ornament, which we did in conjunction with the architect. In normal construction roof overhangs serve a purpose, but our system is designed so they are not necessary.
The Ecocor house is pretty impressive, most of the concepts in the book i read is applied there. How long does an Ecocor house can be built compared to a typical concrete house?
Overhangs are used for shading, to keep for heat coming in thru windows for hot climates, Removing the overhang must mean the Ecocor house can withstand the heat from the sun from coming in the house?
The long side of the building actually faces east-south-east to best fit its location. There is more glazing on the east than ideal for lowest energy use, but with the views from the site we had to make that sacrifice. It's not certified but meets the requirements for the international Passive House association for low-energy buildings. With those houses you don't want too much glazing on the south because it will overheat, even in a cold climate. On the coldest day of the year, the house pictured can be heated comfortably with a standard hair dryer (or other 1500 watt device.) If the heat was never turned on, even in our climate which can reach -20°F (~-30°C) the house will never drop below 50°F (10°C).
The view of the morning sunrise must be amazing there. Im going to check the International Passive House association website. Is that the same as ASHRAE?
The south can overheat in cold climate? In what I read they recommend using the south side for passive heating in cold climates, is that wrong?
In Tropical savanna climate like in manila, if i add glazing to the south side with overhangs, do you think it will overheat?
Thats pretty impressive, I dont understand why not all houses/buildings should be built like that.
Yes, the technology is the same, but essentially run in reverse it functions as a super efficient heat source. Efficiency of electric heating units is measured in COP (coefficient of performance). These units have a COP of about 3.0, meaning for every unit of energy put in, you get three units of energy out. The COP drops somewhat in very cold weather but remains much more efficient than other heat sources
Thank you for the information, is it more energy-intensive to heat or cool a building?
TIA!
Wood Guy
Feb 24, 17 11:09 am
I really thought architecture is just about the built forms based on what i see on the internet, did not know its actually part of earth's processes.
Many architects are amazing artists who focus on the form and let others worry about making the building habitable. Others are more technically oriented but not so good with aesthetics. I try to balance both aspects.
Thats impressive, you must know a lot about the wind, heat flows, pollutions. I want to know what you know. do you have any recommended books to learn it from?
I can't think of a specific, comprehensive book, but you might find these sites helpful in learning more about building science, which is the comprehensive term:
Im going to check the International Passive House association website. Is that the same as ASHRAE?
No, the Passive House Association (http://passiv.de/en/), based in Germany, is focused on specific, low energy metrics. ASHRAE (https://www.ashrae.org/) is a U.S. organization that covers all building types.
The south can overheat in cold climate? In what I read they recommend using the south side for passive heating in cold climates, is that wrong?
In the past, the thought was to add a lot of glass on the south to gain heat. Unfortunately that often leads to too much heat gain, even in cold climates, and associated heat loss at night or on cold, cloudy days because windows aren't very good at holding heat in the building. The current approach is to optimize glazing so you get some free solar energy, but more attention is placed on building an airtight, well-insulated structure. Thousands of built homes have shown the the latter approach uses less energy and provides more comfort.
In Tropical savanna climate like in manila, if i add glazing to the south side with overhangs, do you think it will overheat?
If the overhangs block the sun's rays during the hotter parts of the year, they will not contribute to overheating. Here's an image that shows the idea (mainly the top story):
The size of the overhang depends on the solar elevation angle where you are. Based on the chart you posted above, I would start with the line from the sun to the house at 75° from the ground, and make sure your shading device blocks the sun's rays at that angle.
Thats pretty impressive, I dont understand why not all houses/buildings should be built like that.
I agree, and in my opinion all new homes should be built to the Passive House standard or very close to it. Anything less is laziness, a lack of understanding of the impact building energy use has on the environment, or a lack of care for the environment.
pleiades
Feb 25, 17 9:18 pm
Thank you for the great advice, and the link references, there is too much information there. I still have a long way to go.
No, the Passive House Association (http:passiv.de/en/), based in Germany, is focused on specific, low energy metrics. ASHRAE (https://www.ashrae.org/) is a U.S. organization that covers all building types.//
Is the Passive House Association applicable in other countries?
In the past, the thought was to add a lot of glass on the south to gain heat. Unfortunately that often leads to too much heat gain, even in cold climates, and associated heat loss at night or on cold, cloudy days because windows aren't very good at holding heat in the building. The current approach is to optimize glazing so you get some free solar energy, but more attention is placed on building an airtight, well-insulated structure. Thousands of built homes have shown the the latter approach uses less energy and provides more comfort.
I see, maybe this is also based on the climate of the site? I read in tropical climate you cannot make the building airtight because it might lead to too high humidity?
It makes sense because you cannot control heat gain but can control the building.
If the overhangs block the sun's rays during the hotter parts of the year, they will not contribute to overheating. Here's an image that shows the idea (mainly the top story):
Thanks for the diagram, I need to research overhang design,
Just a question, i noticed that the sun's altitude is used often like in overhang design and shading design, but the sun's azimuth is not, Is there any use for azimuth in building design?
The size of the overhang depends on the solar elevation angle where you are. Based on the chart you posted above, I would start with the line from the sun to the house at 75° from the ground, and make sure your shading device blocks the sun's rays at that angle.
the 75 degree is the month of september, is that right?
I agree, and in my opinion all new homes should be built to the Passive House standard or very close to it. Anything less is laziness, a lack of understanding of the impact building energy use has on the environment, or a lack of care for the environment.
I will focus my research here, it gives architecture more meaning.
TIA!
Wood Guy
Feb 26, 17 10:46 am
Is the Passive House Association applicable in other countries?
Wood Guy
Feb 26, 17 11:23 am
Bummer, I had a long edit that didn't take.
Wood Guy
Feb 26, 17 11:33 am
Is the Passive House Association applicable in other countries?
Yes, it’s popular throughout Europe and gaining ground in the US and Canada, and more recently China and other non-western countries. It’s still a niche market, meaning that although most architects have heard of it at this point, very few are practicing, but it’s influencing architecture everywhere to varying degrees.
I see, maybe this is also based on the climate of the site? I read in tropical climate you cannot make the building airtight because it might lead to too high humidity?
Yes, every climate has its own set of variables. There is an important difference between air tightness and water vapor control. It’s always a good idea to control air flow through building assemblies, but you always need to control water vapor movement. Understanding the difference between the two is the most important element of building science.
Just a question, i noticed that the sun's altitude is used often like in overhang design and shading design, but the sun's azimuth is not, Is there any use for azimuth in building design?
True, in a heating-dominated climate like mine, we are mainly worried about blocking just the worst of the sun’s rays. In your climate you will also want to block the sun as azimuth angles other than 180° (South) and when the sun is at solar elevation angles lower than the summer solstice. That’s why I recommended 75° as a starting point; it would provide shade for roughly six months of the year. You would need to do an energy model to understand the full implications of the overhang design.
pleiades
Feb 27, 17 7:50 pm
Bummer, I had a long edit that didn't take.
I have experienced that also, what I do now is use notepad to write the replies. this way I can easily paste it again in case the internet connection get lost.
Yes, every climate has its own set of variables. There is an important difference between air tightness and water vapor control. It’s always a good idea to control air flow through building assemblies, but you always need to control water vapor movement. Understanding the difference between the two is the most important element of building science.
Thank you for the many advice, I will next study how water vapor moves into building and its effects on the buildings. I'm going to try to get the book that you recommended.
True, in a heating-dominated climate like mine, we are mainly worried about blocking just the worst of the sun’s rays. In your climate you will also want to block the sun as azimuth angles other than 180° (South) and when the sun is at solar elevation angles lower than the summer solstice. That’s why I recommended 75° as a starting point; it would provide shade for roughly six months of the year. You would need to do an energy model to understand the full implications of the overhang design.
Thank you for the advice, I understand the 75 degrees will block sun from april to september, but I'm still going to check it further.
What someone else said about using Sketchup is also great advice--Sketchup is free, and you can locate your building accurately on the globe and see how the shadows change over the course of the day and year. I highly recommend giving it a try.
For energy modeling, I primarily use the PHPP--the Passive House Planning Package, which is extremely thorough and accurate. It's expensive and requires a lot of training, though. For quick studies I use BeOpt, a free resource from the US government (https://beopt.nrel.gov/). It takes a little getting used to and is not perfectly accurate but it does a pretty good job.
pleiades
Feb 28, 17 7:57 pm
Thank you very much Wood Guy! I've learned a lot on this thread. I greatly appreciate all the advice you've given me! Thank you again!
Wood Guy
Feb 25, 17 2:48 pm
Pleiades, I forgot to answer this: is it more energy-intensive to heat or cool a building?
In depends mostly on location. Basically you choose a comfortable interior temperature (65°F/18°C is standard though there are arguments for using higher temperatures) and compare that to the total amount of heat or cooling needed over the course of the year, called heating degree days and cooling degree days. Where I am we have about 8000 heating degree days and 600 cooling degree days, so efficiency of heating equipment is much more significant than that of cooling equipment. Your heating degree days are probably very low, and your cooling degree days much higher, so efficiency of cooling equipment is more important for you.
It gets more complicated, because cooling equipment also has to deal with moisture in the air, there are many fuels that can be used, different up-front equipment costs and different amounts of effort needed for maintenance. Speaking strictly from a physics point of view, it takes the same amount of energy to raise or lower the temperature of a given volume of material by the same amount. However, because of how the equipment works, in reality it takes more energy to cool (and dehumidify) air than it does to heat it.
randomised
Feb 26, 17 12:49 pm
A well designed building around the 14th degree latitude should not require any heating or cooling at all. The invention of the AC made for lazy designers and unsustainable, cheap to build yet expensive to climatise, architecture. Maybe look into old local/(sub)tropical vernacular architecture for truly sustainable solutions that you can borrow from and stay away from the AC!
pleiades
Feb 27, 17 7:57 pm
Thanks for the tips, I'm beginning to appreciate the old architecture here when I understand the science behind it.
Do you have any recommended books or reference to learn more from?
TIA!
Wood Guy
Feb 28, 17 9:12 am
I've never been that far south myself, but have friends who travel around the Pacific basin as nomads. When they come home, they always talk about how hot and humid it is there most of the time. So while I agree with you that lower energy use is better, and that traditional building design incorporated lots of passive cooling strategies, I don't think it's realistic to expect mechanical-free design in today's world--especially in cities.
pleiades
Feb 28, 17 7:40 pm
That could be a psychological factor.
I think a balance of passive and active design is the key.
Helo everyone!
I'm trying to learn about shading buildings, and in the books I've read, they always talk about the North, West, East and South side but never the Northwest, Northeast, Southwest, Southeast side.
Climate is tropical savanna
Latitude is 14
What i know so far
North/South horizontal shading device
East/West Block if possible, Vertical + horizontal shading device
I like to ask for some advice on what to do with these sides (NW,NE,SE,SW)?
Do i based this on the North/South or the East/West?
TIA!
what does tia mean?
hi go do it, TIA means thanks in advance
Well, in the summertime the sun sets in the northwest after reaching a high azimuth to the south at noon, and in the winter in the southwest after reaching a low azimuth to the south at noon, but the variations at 14 degrees of latitude are not all that great. The most critical need for shade would be in the summer, when the sun is at noon (due south but high in the sky) until about 4 or 5 pm when it is still southwest or even due west and lower in the sky. Typically you would not be that concerned with a low setting summertime sun finally slipping below the horizon to the northwest, and I don't think you would be that concerned with a morning sun at least from a prospect of the building becoming uncomfortably hot.
Pleiades, do you understand the path the sun takes as it moves through the sky? I ask honestly; many people do not really understand how this works.
I would treat the SE and SW the same as a south-facing wall, with a horizontal shading device sized to limit insolation during the summer months. Vertical shading devices (typically sliding screens) also work but are not as common as awning structures (e.g., brise soleils).
As Volunteer implied, the NE and NW sun is low on the horizon and its rays have to travel through more atmosphere, so they are not as strong as the mid-day sun.
If the building is over-glazed you can still get morning overheating with NE, E or SE-facing glass, and you can definitely get a blast of unwanted heat on any west-facing glass. Because the sun is low in the sky on the east and west, overhead (horizontal) screening devices don't work unless they are really deep, like a porch, so for low-energy buildings it's important to not overglaze the east and west.
Just to get a feel of the sun path, check out SunCalc for your location and fiddle with the times, my guess is Manila Philippines...
@ Volunteer
Thank you for your help! sorry for beginner questions.
How did you know the variations at 14 degrees are not great?
"The most critical need for shade would be in the summer, when the sun is at noon (due south but high in the sky) until about 4 or 5 pm when it is still southwest or even due west and lower in the sky"
That sentence is amazing! can you tell me how to do something that?
@ Wood Guy
I have some idea, but not sure if its correct though,
What i know so far , please do correct me if I'm wrong,
On the northern hemisphere,
Dec 21 Winter Solstice (Winter) - The sun path is on the south, sunrise at SE, sunset at SW
Mar 21 Equinox - The sun path is still on the south going to the north, sunrise at E, sunset at W
June 21 Summer Solstice (Summertime) - The sun path is on the north, sunrise at NE, sunset at NW
Sept 21 Equinox - The sun path has gone back down to the south, sunrise at E, sunset at W
Is that what you meant with the question "do you understand the path the sun takes as it moves through the sky?"
Thanks for the advice, I will use horizontal shading device for the SE,SW, and limit glazing on the NE,E,SE,W sides
A little off topic, I dont understant these brise soleils, in the pictures with brise soleils, I can see a combination of vertical/horizontal louvers/overhang, it seems like an egg-crate shading, how can you tell if its a brise soleils?
@ randomised
Thank you for the Suncalc app, you are correct in the location
Just a question in the suncalc app, is the yellow part in between the white part the heated are of the sun?
@ all
sorry for the beginner questions, I'm trying to self-learn this because I think this is really important.
do you have any recommended books? especially for tropical savanna building design or general knowledge.
or any software to understand this much better.
TIA all!
The yellow part is just an indication of the sun path I suppose, giving it the idea of height on a 2-dimensional map.
Pleiades, that is correct. The closer you are to the equator, the less difference there is in the sun's position seasonally--both in terms of how far to the north or south of true east or west it rises and sets, and how high the sun is above the horizon. You might find this page helpful: http://www.builditsolar.com/SiteSurvey/site_survey.htm. There is a lot of great information on that site, which has been around a long time.
I see what you mean about searching for brise soleil images. This is what I meant, and how I do horizontal shading devices.
that's a beautiful house, should have shopped the ac unit out of the picture.
Thanks; I wasn't the architect, this was: http://www.johngordonarch.com/houses-1/. I worked for the Passive House panelizing company that built it (http://www.ecocor.us/projects/eastview-passivhaus). (I was involved in all of the detailing, including the brise soleils.) Nothing wrong with a nicely placed, high performance air source heat pump, in my opinion, but I agree it would look cleaner without it. It's on the side of a mountain overlooking the ocean, far from any other houses, so nobody will actually see the outdoor unit.
I was going to ask how that roof drained, but the picture just answered it.
@ randomised
Thanks for the info, what do you usually use the solar path for?
@ Wood Guy
Thank you, but I think I still don't fully understand the sun path,
The part "how high the sun is above the horizon"
is that the altitude of the sun?
I'm going to study the link, thank you for that, I have to make some time reading it slowly, some are new to me.
can I contact you privately if I can't understand something?
Does the term brise soleil can be any shading device like the overhang in your picture?
Thats a very modern building, I like those type of design, the contrast of the wood overhang and the wood porch detail to the white panelized wall is good.
Is the picture showing the south side of the building? for solar heating i guess.
Thats the first time I saw a heat pump, It looks like a split type air condition unit.
TIA all!
I don't consciously use sun path studies, I mostly apply the principles subconsciously.
can you share any principles you always use?
Knowing where the sun rises, how it travels and where it sets, that's all basically.
Very easy to double check in programs like sketchup, if you give the project the correct geolocation you can do simple tests adjusting date and time of your project and see the shadows etc.
Thank you for the tip, I will learn how to do that in sketchup.
Pleiades, I think you are getting the compass points for the rising and setting points of the sun confused with the angular position of the sun at midday. At noon on the summer solstice in Manila the sun is at 81 degrees (with 90 degrees being straight up) and in winter it is at 52 degrees. Face south and put your arm almost straight up for a good approximation of the summer sun height on noon on the summer solstice, and a little more than 45 degrees from the horizon for the position of the sun at noon on the winter solstice position.
yes, i still don't fully understand this,
I checked your quote " At noon on the summer solstice in Manila the sun is at 81 degrees (with 90 degrees being straight up) and in winter it is at 52 degrees." and you're spot on!
http://www.sunearthtools.com/dp/tools/pos_sun.php
Summer
Winter
With the question How did you know the variations at 14 degrees are not great?
The answer is the variation in the altitude is smallI took all the altitude at 12:00PM Day 21st
Month | Altitude
1 | 55.19
2 | 64
3 | 75.67
4 | 87
5 | 84
6 | 81
7 | 84
8 | 87.48
9 | 75
10 | 64
11 | 55
12 | 51
How do you use the altitude in your design?
Face south and put your arm almost straight up for a good approximation of the summer sun height on noon on the summer solstice, and a little more than 45 degrees from the horizon for the position of the sun at noon on the winter solstice position.
I will test that out later!
Pleiades,
The part "how high the sun is above the horizon"
is that the altitude of the sun?
Yes, that is one correct term; another is elevation angle. Both are confusing because altitude and elevation have other meanings. At mid-day, from where you're standing, if you face the sun and draw a line to the horizon, and another line to the sun, the angle between those lines is the solar altitude or elevation angle. At the summer solstice, the angle will be greatest, and at the winter solstice the angle will be least. Where I am at 44° latitude, the angles are 69° in summer and 22° in winter--quite a difference! Where you are the numbers will be closer together, and closer to 90°.
I'm going to study the link, thank you for that, I have to make some time reading it slowly, some are new to me.
can I contact you privately if I can't understand something?
Yes, you can contact me through my profile here, but the discussion may interest others so I would suggest keeping it public. There's no shame in asking questions if you don't understand something. Many architects do not fully understand the significance of solar orientation and the sun's path through the sky. I work in a cold climate and primarily design homes that use 10-20% as much energy as a standard, code-built home, so I have to pay close attention to such details.
Does the term brise soleil can be any shading device like the overhang in your picture?
Yes, brise soleil is just French for sun breaker. There are other terms that serve the same purpose. Awning roof, awning structure, pent roof, sun baffle, or sun-shading-device can all be used for the horizontal structure. Vertical screens are often moveable and called shutters or sliding shutters.
Thats a very modern building, I like those type of design, the contrast of the wood overhang and the wood porch detail to the white panelized wall is good.
Yes, the original design was more traditional but the client came to us to use our system of building super energy efficient homes with a relatively low budget. The budget dictated removing all ornament, which we did in conjunction with the architect. In normal construction roof overhangs serve a purpose, but our system is designed so they are not necessary.
Is the picture showing the south side of the building? for solar heating i guess.
The long side of the building actually faces east-south-east to best fit its location. There is more glazing on the east than ideal for lowest energy use, but with the views from the site we had to make that sacrifice. It's not certified but meets the requirements for the international Passive House association for low-energy buildings. With those houses you don't want too much glazing on the south because it will overheat, even in a cold climate. On the coldest day of the year, the house pictured can be heated comfortably with a standard hair dryer (or other 1500 watt device.) If the heat was never turned on, even in our climate which can reach -20°F (~-30°C) the house will never drop below 50°F (10°C).
Thats the first time I saw a heat pump, It looks like a split type air condition unit.
Yes, the technology is the same, but essentially run in reverse it functions as a super efficient heat source. Efficiency of electric heating units is measured in COP (coefficient of performance). These units have a COP of about 3.0, meaning for every unit of energy put in, you get three units of energy out. The COP drops somewhat in very cold weather but remains much more efficient than other heat sources.
At the summer solstice, the angle will be greatest, and at the winter solstice the angle will be least. Where I am at 44° latitude, the angles are 69° in summer and 22° in winter--quite a difference! Where you are the numbers will be closer together, and closer to 90°.
I see now, when your farther away the equator, the sun's altitude variation is greater.
Yes, you can contact me through my profile here, but the discussion may interest others so I would suggest keeping it public.
Thank you very much sir Wood Guy,
Many architects do not fully understand the significance of solar orientation and the sun's path through the sky. I work in a cold climate and primarily design homes that use 10-20% as much energy as a standard, code-built home, so I have to pay close attention to such details
I really thought architecture is just about the built forms based on what i see on the internet, did not know its actually part of earth's processes.
Thats impressive, you must know a lot about the wind, heat flows, pollutions. I want to know what you know. do you have any recommended books to learn it from?
Yes, brise soleil is just French for sun breaker. There are other terms that serve the same purpose. Awning roof, awning structure, pent roof, sun baffle, or sun-shading-device can all be used for the horizontal structure. Vertical screens are often moveable and called shutters or sliding shutters.
I see, I will use brise soleil in describing shading device now, it sounds exquisite.
Yes, the original design was more traditional but the client came to us to use our system of building super energy efficient homes with a relatively low budget. The budget dictated removing all ornament, which we did in conjunction with the architect. In normal construction roof overhangs serve a purpose, but our system is designed so they are not necessary.
The Ecocor house is pretty impressive, most of the concepts in the book i read is applied there. How long does an Ecocor house can be built compared to a typical concrete house?
Overhangs are used for shading, to keep for heat coming in thru windows for hot climates, Removing the overhang must mean the Ecocor house can withstand the heat from the sun from coming in the house?
The long side of the building actually faces east-south-east to best fit its location. There is more glazing on the east than ideal for lowest energy use, but with the views from the site we had to make that sacrifice. It's not certified but meets the requirements for the international Passive House association for low-energy buildings. With those houses you don't want too much glazing on the south because it will overheat, even in a cold climate. On the coldest day of the year, the house pictured can be heated comfortably with a standard hair dryer (or other 1500 watt device.) If the heat was never turned on, even in our climate which can reach -20°F (~-30°C) the house will never drop below 50°F (10°C).
The view of the morning sunrise must be amazing there.
Im going to check the International Passive House association website. Is that the same as ASHRAE?
The south can overheat in cold climate? In what I read they recommend using the south side for passive heating in cold climates, is that wrong?
In Tropical savanna climate like in manila, if i add glazing to the south side with overhangs, do you think it will overheat?
Thats pretty impressive, I dont understand why not all houses/buildings should be built like that.
Yes, the technology is the same, but essentially run in reverse it functions as a super efficient heat source. Efficiency of electric heating units is measured in COP (coefficient of performance). These units have a COP of about 3.0, meaning for every unit of energy put in, you get three units of energy out. The COP drops somewhat in very cold weather but remains much more efficient than other heat sources
Thank you for the information, is it more energy-intensive to heat or cool a building?
TIA!
I really thought architecture is just about the built forms based on what i see on the internet, did not know its actually part of earth's processes.
Many architects are amazing artists who focus on the form and let others worry about making the building habitable. Others are more technically oriented but not so good with aesthetics. I try to balance both aspects.
Thats impressive, you must know a lot about the wind, heat flows, pollutions. I want to know what you know. do you have any recommended books to learn it from?
I can't think of a specific, comprehensive book, but you might find these sites helpful in learning more about building science, which is the comprehensive term:
https://buildingscience.com/
http://www.greenbuildingadvisor.com/
http://www.finehomebuilding.com/
Im going to check the International Passive House association website. Is that the same as ASHRAE?
No, the Passive House Association (http://passiv.de/en/), based in Germany, is focused on specific, low energy metrics. ASHRAE (https://www.ashrae.org/) is a U.S. organization that covers all building types.
The south can overheat in cold climate? In what I read they recommend using the south side for passive heating in cold climates, is that wrong?
In the past, the thought was to add a lot of glass on the south to gain heat. Unfortunately that often leads to too much heat gain, even in cold climates, and associated heat loss at night or on cold, cloudy days because windows aren't very good at holding heat in the building. The current approach is to optimize glazing so you get some free solar energy, but more attention is placed on building an airtight, well-insulated structure. Thousands of built homes have shown the the latter approach uses less energy and provides more comfort.
In Tropical savanna climate like in manila, if i add glazing to the south side with overhangs, do you think it will overheat?
If the overhangs block the sun's rays during the hotter parts of the year, they will not contribute to overheating. Here's an image that shows the idea (mainly the top story):
The size of the overhang depends on the solar elevation angle where you are. Based on the chart you posted above, I would start with the line from the sun to the house at 75° from the ground, and make sure your shading device blocks the sun's rays at that angle.
Thats pretty impressive, I dont understand why not all houses/buildings should be built like that.
I agree, and in my opinion all new homes should be built to the Passive House standard or very close to it. Anything less is laziness, a lack of understanding of the impact building energy use has on the environment, or a lack of care for the environment.
Thank you for the great advice, and the link references, there is too much information there. I still have a long way to go.
No, the Passive House Association (http:passiv.de/en/), based in Germany, is focused on specific, low energy metrics. ASHRAE (https://www.ashrae.org/) is a U.S. organization that covers all building types.//
Is the Passive House Association applicable in other countries?
In the past, the thought was to add a lot of glass on the south to gain heat. Unfortunately that often leads to too much heat gain, even in cold climates, and associated heat loss at night or on cold, cloudy days because windows aren't very good at holding heat in the building. The current approach is to optimize glazing so you get some free solar energy, but more attention is placed on building an airtight, well-insulated structure. Thousands of built homes have shown the the latter approach uses less energy and provides more comfort.
I see, maybe this is also based on the climate of the site? I read in tropical climate you cannot make the building airtight because it might lead to too high humidity?
It makes sense because you cannot control heat gain but can control the building.
If the overhangs block the sun's rays during the hotter parts of the year, they will not contribute to overheating. Here's an image that shows the idea (mainly the top story):
Thanks for the diagram, I need to research overhang design,
Just a question, i noticed that the sun's altitude is used often like in overhang design and shading design, but the sun's azimuth is not, Is there any use for azimuth in building design?
The size of the overhang depends on the solar elevation angle where you are. Based on the chart you posted above, I would start with the line from the sun to the house at 75° from the ground, and make sure your shading device blocks the sun's rays at that angle.
the 75 degree is the month of september, is that right?
I agree, and in my opinion all new homes should be built to the Passive House standard or very close to it. Anything less is laziness, a lack of understanding of the impact building energy use has on the environment, or a lack of care for the environment.
I will focus my research here, it gives architecture more meaning.
TIA!
Is the Passive House Association applicable in other countries?
Bummer, I had a long edit that didn't take.
Is the Passive House Association applicable in other countries?
Yes, it’s popular throughout Europe and gaining ground in the US and Canada, and more recently China and other non-western countries. It’s still a niche market, meaning that although most architects have heard of it at this point, very few are practicing, but it’s influencing architecture everywhere to varying degrees.
I see, maybe this is also based on the climate of the site? I read in tropical climate you cannot make the building airtight because it might lead to too high humidity?
Yes, every climate has its own set of variables. There is an important difference between air tightness and water vapor control. It’s always a good idea to control air flow through building assemblies, but you always need to control water vapor movement. Understanding the difference between the two is the most important element of building science.
You asked earlier about books. This one is thorough: https://www.amazon.com/Water-Buildings-Architects-Guide-Moisture/dp/0471468509. Most of it will be too advanced for you right now but it’s not too early to start learning the principles.
Just a question, i noticed that the sun's altitude is used often like in overhang design and shading design, but the sun's azimuth is not, Is there any use for azimuth in building design?
True, in a heating-dominated climate like mine, we are mainly worried about blocking just the worst of the sun’s rays. In your climate you will also want to block the sun as azimuth angles other than 180° (South) and when the sun is at solar elevation angles lower than the summer solstice. That’s why I recommended 75° as a starting point; it would provide shade for roughly six months of the year. You would need to do an energy model to understand the full implications of the overhang design.
Bummer, I had a long edit that didn't take.
I have experienced that also, what I do now is use notepad to write the replies. this way I can easily paste it again in case the internet connection get lost.
Yes, every climate has its own set of variables. There is an important difference between air tightness and water vapor control. It’s always a good idea to control air flow through building assemblies, but you always need to control water vapor movement. Understanding the difference between the two is the most important element of building science.
You asked earlier about books. This one is thorough: https:www.amazon.com/Water-Buildings-Architects-Guide-Moisture/dp/0471468509. Most of it will be too advanced for you right now but it’s not too early to start learning the principles.//
Thank you for the many advice, I will next study how water vapor moves into building and its effects on the buildings.
I'm going to try to get the book that you recommended.
True, in a heating-dominated climate like mine, we are mainly worried about blocking just the worst of the sun’s rays. In your climate you will also want to block the sun as azimuth angles other than 180° (South) and when the sun is at solar elevation angles lower than the summer solstice. That’s why I recommended 75° as a starting point; it would provide shade for roughly six months of the year. You would need to do an energy model to understand the full implications of the overhang design.
Thank you for the advice, I understand the 75 degrees will block sun from april to september, but I'm still going to check it further.
Found this website, maybe other will find it useful to overhang design
http://susdesign.com/tools.php
What software do you use for energy modeling?
That's a good tool for overhang design.
What someone else said about using Sketchup is also great advice--Sketchup is free, and you can locate your building accurately on the globe and see how the shadows change over the course of the day and year. I highly recommend giving it a try.
For energy modeling, I primarily use the PHPP--the Passive House Planning Package, which is extremely thorough and accurate. It's expensive and requires a lot of training, though. For quick studies I use BeOpt, a free resource from the US government (https://beopt.nrel.gov/). It takes a little getting used to and is not perfectly accurate but it does a pretty good job.
Thank you very much Wood Guy! I've learned a lot on this thread. I greatly appreciate all the advice you've given me! Thank you again!
Pleiades, I forgot to answer this: is it more energy-intensive to heat or cool a building?
In depends mostly on location. Basically you choose a comfortable interior temperature (65°F/18°C is standard though there are arguments for using higher temperatures) and compare that to the total amount of heat or cooling needed over the course of the year, called heating degree days and cooling degree days. Where I am we have about 8000 heating degree days and 600 cooling degree days, so efficiency of heating equipment is much more significant than that of cooling equipment. Your heating degree days are probably very low, and your cooling degree days much higher, so efficiency of cooling equipment is more important for you.
It gets more complicated, because cooling equipment also has to deal with moisture in the air, there are many fuels that can be used, different up-front equipment costs and different amounts of effort needed for maintenance. Speaking strictly from a physics point of view, it takes the same amount of energy to raise or lower the temperature of a given volume of material by the same amount. However, because of how the equipment works, in reality it takes more energy to cool (and dehumidify) air than it does to heat it.
A well designed building around the 14th degree latitude should not require any heating or cooling at all. The invention of the AC made for lazy designers and unsustainable, cheap to build yet expensive to climatise, architecture. Maybe look into old local/(sub)tropical vernacular architecture for truly sustainable solutions that you can borrow from and stay away from the AC!
Thanks for the tips, I'm beginning to appreciate the old architecture here when I understand the science behind it.
Do you have any recommended books or reference to learn more from?
TIA!
I've never been that far south myself, but have friends who travel around the Pacific basin as nomads. When they come home, they always talk about how hot and humid it is there most of the time. So while I agree with you that lower energy use is better, and that traditional building design incorporated lots of passive cooling strategies, I don't think it's realistic to expect mechanical-free design in today's world--especially in cities.
That could be a psychological factor.
I think a balance of passive and active design is the key.