Showing posts with label building shading. Show all posts
Showing posts with label building shading. Show all posts

Wednesday, August 17, 2016

Good and bad shading in Bangkok fashion area

These two examples of east-facing condos in one of Bangkok's most fashionable districts show different attention to thermal detail that has great impact on interior comfort.

The first building is an older expensive building with an impressive street level facade but little upper floor protection against strong morning sun. As you can see many of the rooms have no provision for shading. Interior curtains will rapidly rise to 40 degrees or more soon after sunrise, subsequently transferring by convection alone 100 watts or more per square meter of window into the interior air. If as it appears the entire wall or most of it is glass, it will take all the cooling an air conditioner can provide to offset morning warming. This makes for highly uncomfortable conditions especially if the room is a bedroom.

People who buy units like this are impressed by views. But in truth once they occupy the place they realize that they actually don't care for the glare and lack of privacy so they leave the curtains closed all or much of the time, leaving the room with no natural light. This irrational consumer behavior is exemplified by the old American advertising saying, "they buy the sizzle, not the steak."

The second building is a more utilitarian modern design with smaller east-facing windows. The building long axis is roughly east-west so the views from the units are north and south, and the sun strikes the living space windows at a sharp angle -- less exposed area and higher reflection coefficients (for glass). Note however that some of the northerly windows have no shading from decks. With the early sun now at this time of year (August) well to the north of the long axis of the building (the building axis is 102 deg east, not 90 deg) significant heating will occur in the early morning hours in those rooms or spaces. Other windows, probably the living areas, are well shaded by being recessed. I will show this in another entry, using my own building as an example backed up by Netatmo weather station data.

The showroom near street level strikes me as a solar oven. Sometimes tinted glass is used to attempt to mitigate this solar heating but it should be remembered that dark glass absorbs solar heat. The glass itself gets hot, and this heat, or a significant amount of it, is convected into the interior.