The hot season broken by moisture

Mid-May dawn: with the coming of rainy and cloudy weather, the back of the hot season seems to be broken, with dawn temperatures below 30 degC (86F) in my downtown neighborhood. At the peak of the hot weather a couple of weeks back they were consistently over 30. 

Notice the 28-30 temps downtown and the 27 or so further out including the Don Muang airport area where our long-term records are. This agrees with my previous study indicating a 2-3 deg "heat island effect" in the Sukhumvit area.

Afternoon Bangkok sun blasts glassy condos

In an earlier post we showed how anyone seeking a "view condo" pays the penalty of terrible heat either in the morning (east facing) or afternoon (west facing). Curtains, blinds, or dark glass don't help much, they just heat up to 50 deg C (130F) and act like ski-cabin radiators. Ugh! Few of us think of this when we buy a condo, we are charmed by views which become minor considerations after we occupy a condo for a few weeks.

Be warned! Air conditioning does not alleviate this radiant heat problem!

Netatmo shows local heat island effect in Bangkok

This is a mix of select data showing you local differences in dawn temperature. On the recent right side you can see several sources superimposed. My condo Netatmo outside temp (brown) is the highest, probably because of all the walls and concrete that surround the sensor. The yellow points from the Planetorium are very similar, suggesting that the Sukhumvit area overall has a generally elevated temperature probably from urban heat island effects, about +3 C degrees heating.

Red points are Don Muang data, for which I have long term data, and green points from Korat, higher elevation and upcountry, generally 2-3 deg lower than Bangkok. The new airport at Souvanaphoum is also a little lower than Don Muang; it's further out of town.

Notice how last year the morning low at Don Muang was over 30 for several days. No such days this year at Don Muang, so last year's peak was a little worse, because the rains came a little later. (Sukhumvit area is this year is over 30, only because of +3 deg heat island effect). I had earlier expected this year to be worse by comparison, but that was before I realized that my Netatmo local readings were boosted by urban heat island warming.

If I want to estimate Don Muang dawn temperature from my Netatmo data I should subtract 3 deg. These corrected values are also plotted here shown as blue points.

So we have just now this week hit the probable high point in discomfort for 2017. To me it was suffocating. I found myself turning on the aircon all the time. My pub mate Al, exactly my age: "I never complained about the heatt here before, but this year it really hit me." We both thank clouds and rain that are now pulling the dawn temperature down into the mid 20s.

But even now today I am turning on aircon on arriving home at the end of the day, after 6 pm.

Glass condos: good way to throw away money and suffer at the same time

So when you buy a west or worse east facing condo with those big glass walls that are fashionable now in Bangkok (Wow! Look at that view!) you don't think of the expense and years of misery you are taking on. But let's start with my glass door to a small veranda exposed this month to morning sun from about 8 to 11 am. Here are the calcs for refrigeration capacity and expense. A sunny morning heats the curtains to about 50 C, which then serve the same function as hot water radiators. To offset this added heat I need a dedicated 26000 BTU split air conditioner unit, it barely provides the needed 10 kw of cooling power (2.6 kw electric power). So maybe you need two such units for this small room?

But you have plenty of money, so problem solved!

No, not at all. When you look at that curtain on waking up, you are looking not at a 25 degree cooled wall, but at a 50C heating panel, and though the room air may be 25 C, you are feeling that blast of radiant heat, as unwelcome on your face and body as it might be welcome in a northern ski lodge.

I will claim that it is not possible to live comfortably in such an environment, being driven from bed every morning because of solar heating via windows, regardless of air conditioning and curtains, blinds, etc which do little to prevent heating in the room, especially radiant heating from interior window coverings (or tinted windows). But anyone who has ever parked a closed car in the sun knows this already!