Building Cool; passive cooling architecture

[WhiteLotusLane]

The absolute strength of this forum are the topics that completely cover a particular subject, often started by an expert on the topic at hand.

So without further ado.. let me state that sadly I'm not that expert. However the topic in the title is something that I am very interested in, so I hope the real craftsmen stand up and submit their 2 saleung's worth.

Rationale: Thailand can be one of the hottest and most humid places on earth, yet you often see new buildings going up with airconditioning in mind (or, nothing in mind) rather than building 'sensibly', taking advantage of natural ways to lower the temperature so that no (or less) air-conditioning is needed. Such houses would make healthier, more comfortable places, and as electricity costs aren't going down, chances are you will notice the difference month after month in reduced electricity costs.

The only things I can contribute at this point are some good links on the topic, that deal with the various (and very different) strategies that can be implemented.

I'd like to do this one all the way from the very beginning: selecting a plot of land to build on and positioning the house, and take it all the way to the end to the final placement of any mechanical cooling equipment.

Perhaps you have some pictures/examples of houses that either get this right, or get it horribly wrong.. Both would be educational.

Links:

Your Home Technical Manual - 1.0 Passive Design Introduction
(Aussie government site on 'Design for Lifestyle and the future')

Passive Cooling Techniques
('Build it solar' -- passive cooling)

[Marmite the Dog]

There's a condo being built on Sukhumvit 23 with passive cooling in mind. Shite name though (as ever).

Wind Sukhumvit 23

Also, I know someone who has just built a place in Hua Hin with a passively cooled living room. Not sure if it works though.

[WhiteLotusLane]

The Regent Cha Am (in between Cha Am and Hua Hin) would be an example; their lobby is completely open on two sides, with one side facing the sea. It's incredibly breezy.

Rooms however don't benefit in the same way, as they face on to an enclosed internal garden, where air doesn't really flow.

[blackgang]

But even at best, there is only so much you can do with a building to keep it cool inside if the air temp outside is so hot and humid, that means keeping what air you have cooled away from air that is 100 degrees and 90% humidity.
Cabo San Lucas is just such a place that is about the same latitude as is here, but is close to the cool pacific ocean and completely surrounded by sea. ambient temp there will be 83, while at my house it is 103 with same humidity.
So I have to run my aircons to find the cool temps, and insulation and a tighter construction to keep the artifically cooled and dried air away from the outside air.
even there if you are in direct sunlight you will cook while in the shade the air feels cool.

Insulation is the only thing that will do any good where the air is so hot.

[Sir Burr]

If you look at houses build in the tropics, no matter what country, they have certain characteristics that are the same that aid in cooling.
Firstly, they are usually on stilts. This stops conduction of heat from the ground.
Secondly, they have very large eaves. This stops the sun shining on the walls.
Thirdly, they have taller than average ceilings. What hot air does accumulate, rises to above head height.
Fourthly, they have steep, large volume rooves. This sheds rain quickly and the roof has too much air in it to heat up too much.
Fifthly, the roof is ventilated, so that there is always an airflow. This ensures that the air in the roof is always cool.

[WhiteLotusLane]

Thailand is a bit on the boundary though.. Especially upcountry to the North and North East. During much of the year there, it isn't all THAT humid, so a breeze could actually do some good there.

Of course a combination is also possible, with parts of the house being high mass & loads of insulation with perhaps a small airconditioner for the hot season, and other parts of the house with a more 'open' and breezy layout.

[Marmite the Dog]

Also, many are constructed from wood, which is much cooler than concrete and small windows.

[buad hai]

I tried to do this with my house in Saipan. It was wood. It was on stilts. It had a very high roof with clerestory windows across the top for ventilation. It had shaded porch all around and was strategically placed to catch the breeze. It had ceiling fans. It had reflective insulation in the walls and roof. It had trees all around that shaded the ground and directed the breeze to the house.

But, there were just too damn many days with zero breeze and near 100% humidity. As Blackgang points out, there's only so much you can do.

When I added on a building with a couple of bedrooms I built it out of concrete, put two inches of foam insulation in the roof slab and air conned the beast. Where do you think we spent our time? Hint: It wasn't in the passively cooled part of the house.

[blackgang]

They have a new type house for hot country home in Mexico anymore, Building a lot of them up at Puerta Penyasca[sp] Northern sea of cortez, hot sumbitch and little breeze, and a few other places.
A slab with positioned single rebars sticking up, shoved down over these is 6 or 8 inch 4'x8' sheets of solid styrofoam, hooks every so ofter to hold wall sheets, formed prestressed concrete rafter roof beams into which 8 or 10" sheets of styrofoam are fitted, the roof is covered with 1 1/2 inch of special concrete, and windows of thermopane with vinyl sash and doors are fitted, the walls are stuccoed well inside and out, one small aircon, like living in a walkin freezer with windows.
Fast, cheap construction and nothing to rot or feed bugs.

[DrAndy]

If you look at my house thread, you can see that I have tried to build it with coolness in mind.

as mentioned above, it is on stilts, made of wood, has a high roof with clitoris (hah) windows at the top, decent sized eaves etc etc

The main house also faces north, so the kitchen and toilets, the concrete part, face the sun

when we have been in the upstairs, it seems very cool, especially when the cool wind comes off the damp rice fields, very nice. It stays as cool as down under the house, unlike my house in Chiang Mai, where the upper part gets too hot even with all the shutters open.

In addition, I have used some insulating foil under the tiles.

[El Gibbon]

If you look at houses build in the tropics, no matter what country, they have certain characteristics that are the same that aid in cooling.
Firstly, they are usually on stilts. This stops conduction of heat from the ground.
Secondly, they have very large eaves. This stops the sun shining on the walls.
Thirdly, they have taller than average ceilings. What hot air does accumulate, rises to above head height.
Fourthly, they have steep, large volume rooves. This sheds rain quickly and the roof has too much air in it to heat up too much.
Fifthly, the roof is ventilated, so that there is always an airflow. This ensures that the air in the roof is always cool.

Some time ago I posted a link and article re. some public housing that had been proposed for Bangkok. Can't find it now and didn't keep a copy. One of the main considerations was the overall orientation of the building. The long sides should be positioned to take advantage of whatever natural air flow there is. In Thailand (in general terms) that means that the long axis should be in the North South direction.

The idea being that a total air exchange is much faster along the short axis than the long one. If you note, especially in the areas below Bangkok, where monsoon winds are prevelant in either of the directions depending on the season, older buildings are generally set up like this.

Pretty basic idea but one often overlooked when situating a building to live in. More often than not the 'view' from the area most lived in takes priority.

E. G.

[WhiteLotusLane]

The long sides should be positioned to take advantage of whatever natural air flow there is. In Thailand (in general terms) that means that the long axis should be in the North South direction.

Ah.. interesting.. However that also means that the length of the house is exposed to the sun in the morning and afternoon. I've read websites that say you should position the length of the house East-West, so the surface exposed to the afternoon sun is smallest.

I guess even before buying land and picking a part to build on it would be good to check where the wind (if any) is coming from in every season.

[WhiteLotusLane]

I tried to do this with my house in Saipan. It was wood. It was on stilts. It had a very high roof with clerestory windows across the top for ventilation. It had shaded porch all around and was strategically placed to catch the breeze. It had ceiling fans. It had reflective insulation in the walls and roof. It had trees all around that shaded the ground and directed the breeze to the house.

But, there were just too damn many days with zero breeze and near 100% humidity. As Blackgang points out, there's only so much you can do.

When I added on a building with a couple of bedrooms I built it out of concrete, put two inches of foam insulation in the roof slab and air conned the beast. Where do you think we spent our time? Hint: It wasn't in the passively cooled part of the house.

Thanks.. So I think it would be a good strategy to do both.. After all it's not super hot and humid in Thailand all of the time, just some of the time, especially up-country North and North East.

One more thing though, in two storey buildings it seems the lower floor remains cooler than upstairs. Often there would be a tile floor that's just wonderfully cool.

So you could go with a heavy, shielded & insulated lower part away from the sun with possibly even a small airconditioner in there because the strategy is 'keep cool as long as possible'. Then separately there is an elevated, lighter & breezier part that will warm up quicker from the outside air, but in the afternoon will also cool down real quick with a breeze blowing through, perhaps rain, etc.

[peterpan]

They have a new type house for hot country home in Mexico anymore, Building a lot of them up at Puerta Penyasca[sp] Northern sea of cortez, hot sumbitch and little breeze, and a few other places.
A slab with positioned single rebars sticking up, shoved down over these is 6 or 8 inch 4'x8' sheets of solid styrofoam, hooks every so ofter to hold wall sheets, formed prestressed concrete rafter roof beams into which 8 or 10" sheets of styrofoam are fitted, the roof is covered with 1 1/2 inch of special concrete, and windows of thermopane with vinyl sash and doors are fitted, the walls are stuccoed well inside and out, one small aircon, like living in a walkin freezer with windows.
Fast, cheap construction and nothing to rot or feed bugs.

I don't know why they don't use more of this style of materials here. I built a Styrofoam house in NZ 25 years ago, Concrete sprayed over chicken wire which was attached to the Styro. The house was conventionally framed inside to which plaster board was attached. House is up on hill over looking the sea in Auckland so high wind loadings and no problems with the structure.
It was 3 stories high and open design to promote fast circulation within the structure. Great place, didn't ever need cooling or heating.

[everglaze]

can one buy 6-8 inch 4X8 styro sheets in thailand and how much?

I would like to build a second home and the styro looks like the best
option.

[blackgang]

It is just a little more than the styro sheets, there are plans and special fittings and then there are plans for the making of the roof rafter beams, in fact I think they were sold with the kit already finished.
I have friends living on Baja and will ask if they can get a set of the info plans and promo stuff and scan it or send me the name of the co.
I did look some when we were going to build, but ya know Thai, I am married to one..
As far as I know about E.W. orientation, in the northern USA we always built with the living room facing south.
In the summer the sun comes up in the northern part and away from the living room, in the winter the sun will shine in the windows furnishing warmth and light most of the day.
East-West here has something to do with Buda and the bad shit, I ain't figured it out yet, but I do know that there ain't gonna be no Thai with his head west while sleeping.

[buad hai]

Some years ago there was a product marketed in the US called "W Panel". This was a two inch thick sheet of foam within a cage of reinforcing hardware cloth. The idea was to build the entire house out of this stuff and then spray concrete (gunite) on the assembled foam panels. A guy was doing this on Saipan, but the gunite machine broke and then he went broke. I bought some of the panels to embed in the roof of the concrete section of my house. It worked fine. The few houses he managed to finish held up well and were very inexpensive to cool.

Have a look here:

Green Sandwich Technologies

[Sir Burr]

You don't have to use styroform (fire-hazard?) or, any kind of insulating materials if you get the design right.

[El Gibbon]

The long sides should be positioned to take advantage of whatever natural air flow there is. In Thailand (in general terms) that means that the long axis should be in the North South direction.

Ah.. interesting.. However that also means that the length of the house is exposed to the sun in the morning and afternoon. I've read websites that say you should position the length of the house East-West, so the surface exposed to the afternoon sun is smallest.

I guess even before buying land and picking a part to build on it would be good to check where the wind (if any) is coming from in every season.

Check out the 2nd item in the OP. Large/long eaves... will keep most of the mid day sun off of the long walls.

The orientation is in addition to the items listed in the OP.

E. G.

[Ban Saray]

Orientation - Thais will not sleep east west, but then you design rooms to suit.
I am building a square house orienation doesn't matter, but window loaction does. I'm on stilts on a hill, plenty of breeze as I'm near the beach.
Timber walls, gypsum interior, all walls will be foamed or insulated with batts.
Roof, use terra cotta tiles, foam sprayed, then ceiling lined with more batts.
Large roofed veranda - 6 metres - on west side to take in sunset and beach view
Trees selected to offer shade at roof level and allow wind through and under house.
I don't need air-con.
But as a soon as I get neighbours I'm sure they will stuff all of this up with brick monoliths.

[WhiteLotusLane]

Orientation - Thais will not sleep east west, but then you design rooms to suit.

I just found out that Northerners apparently don't sleep North-South, with their head pointing North. This is exclusively for dead bodies, who ARE positioned with their head pointing North.

Sady the only wall in the main bedroom that has enough flat space to put a bed against is a North facing wall. So a compromise was reached, we put the bed up against the wall as usual, however we sleep West-East in it.

[Dougal]

The bungalow I live in has no roof insulation and only vents under the eaves. The walls are 4cm cinder block with aluminium frame black glass windows. I have no A/C. With doors and windows open the best temperature I can achieve at the moment is 35c.

My new house is built with 20cm thermal block. Foil under the eaves and foil backed ceiling plasterboard. PVC framed windows with black glass. The roof is vented and in the living area the ceiling is pitched half cathedral with roof vents.

With all windows and doors closed the internal temperature is 31c.

[Marmite the Dog]

Someone's nicked your settee as well mate.

[Dougal]

^ That's my roller blading room.

[Thetyim]

^ Looks nice. What's the white bit in the ceiling ?