Thai comfort II (the mysterious orient)

Ron: So Dah, do you think Thai people feel the heat the same as fahlang? Sometimes when I feel very hot my girlfriend also says "very hot" too.

Dah: Thai people say "Oh very hot" but just start the conversation, that all. It not about real hot. Actually it not bother them. It just the way it is. After you born it like this, no one can change. Even you go to hospital and doctor there make mistake, you have to think maybe I do bad last life, that's why I get. In America if someone do something bad, you have to sue him to get something back. But in Thai they think maybe last life I do something bad to them.

Ron: I see. But Jack told me last few days you were complaining about the heat at night. Were you just making conversation?

Dah: No, it about the flea, that bug, I don't know if flea or not. It bother me. Not the heat.

A long way from home

I grew up in New England.

The summers, especially the "Dog Days of August" were sultry; the fall was crisp and delicious, and then the "frost was on the pumpkin" and the rains came and then the howling "Nor' Easter" storms that closed all schools, we heard the good news on the radio in the morning. Serious businessmen like my father trekked through the drifts to work anyway, never missed a day.

Boston as always thought the best of itself and everyone said that the vigorating seasons were what made people alert and industrious, compared, for example, to Mexico, where everyone slept away the day, and Havana, God knows what they did down there. But then you'd think about that, whatever they did do down there, maybe it wouldn't be so bad after all, the warm wind on the Malecon and the bar lights twinkling and one night when I finally went there to see what was going on I went into one the bars and there was a juke box playing Nat King Cole and a couple of girls sitting at the bar and...well that's another story. The funny thing is, my father, the serious busibnessman, once had a Cuban girlfriend. But this was the tropics, people ran away to places like that, it was hot and sticky and sweating far into the night, the weather just did things to you. Made you irresponsible.

But getting back to Boston, as soon as the days that my mother called the "dog days of August" were over, bright and sparkling September came along and I walked to school kicking the yellow and orange maple leaves. I loved that weather, the smell of those leaves burning in the fall. Halloween was just around the corner, and then soon enough the "frost would be on the pumpkin."

But all of that was half century ago at latitude 42, and aside from my nightly film festival of dreams of those sparkling times and those Kodachrome neighborhoods, my days now, and probably all my future days, will be at a very different latitude, latitude 13. Think Djibouti, or Cape Verde, or the Marshall Islands, or who knows where in Africa.


Now I live a long way from home.

Think heat.

Think humidity.

Or think Bangkok, Thailand, where I am writing this entry, waiting for the sun to go down, then I'm going out into this traffic you see here, and do some things I'll discuss later in this blog.

Enter humidity

My mother called it "sticky", and it's a subject that we've been avoiding here, hoping that the weather would just stay cool enough. But when the Don Muang temp hits 29.5 as it did the last couple of nights we just can't seem to convect and radiate that heat away, and the dreaded sweat begins to bubble from our pores and we have to get our hard little pillow, however full of mold it may be (according to our faithful correspondent wch). The other day I took a wet washcloth out on the deck in the shade with a nice breeze and let it dry a bit. It was ten inches square and after an hour it had lost 8 grams of moisture, that's about 5 watts of cooling power, equivalent to 80 watts per square meter.

Depends on wind and humidity, you're thinking, so here's a formula to figure it for whatever you like:

Evaporation in tropics, grams
E=(25+19*V)*(30*(1-RH)/3.6/1000)*A*T
E=evaporation, grams
V=wind, m/s
RH=relative humidity
A=area, sm
T=time, sec

And here is a handy little graph of that formula:

Now you might have the same problem that I do here, because when I try to find a rate of 80 watts per square meter on this grpah, I don't. So maybe I'm a lousy experimentalist, or the formula, which is supposed to be for open pan evaporation, doesn't work for wet washcloths. I'll have to look into it. But what you can see in general here is what you know already, that is, when you begin to sweat to the point where half of your boys is soaked, and you're in a good breeze on a hot dryish day, you get a lot of cooling power, enough to take care of the 200 watts or so that you generate when excercising.

Are the Thai really different?

For some years academics have been debating whether thermal comfort varies among different enthnicities, with the balance of opinion seeming to shift in these days of multicultural pride toward discoveries of ethnic difference. A recent study by a Thai professor at the excellent Silpakorn University follows thsi view by concluding, based on a field survey of many Thai people in their own settings, that Thai prefer much warmer and more humid environments than fahlang. Based on my experience giving bedtime thermal comfort questionnaires to my girlfriend (is that why she is mad at me?), I half believe this, and when I read the paper by the professor I knew that I was supposed to believe it without question.

You saw the Olgyay chart in the last posting here, and now you can see the results of the survey here.

Do you believe it?

I've superimposed the zone of favored conditions for Thai people on top of the Olgyay bioclimatic zone diagram shown last post. Do you think the Thai are most comfortable in their ordinary lives and activities at a temperature of 30 and RH of 80 percent? The warmer days and nights of last month (April 2007)? This is certainly enough to make me miserable.

I wonder. I have some methodological issues with the research, but I'm going to give you the link to the paper below so you can make up your own mind. We'll talk more about his later, meanwhile I look forward to your views.

http://www.unige.ch/cuepe/html/plea2006/Vol2/PLEA2006_PAPER842.pdf

Hungarian attack on US hegemony

The reader has been introduced to the famous Carrier psychrometric chart which will be easly recognized as an attempt to confuse and perplex ordinary people with the goal of herding them like sheep into the corrals of air conditioning salesmen. Air conditioning engineers, whomever they may be, love this Carrier chart with its arcane title, its Cal Tech terminology ("enthalpy", etc). Internationals hate it because it is just one more attempt to foist American hegemony on the world. Architects despair at knowing which is up and which is down and which is sideways on the chart, the French hate it because it spelled the death of Scientific French as surely as McDonalds has proven to be Vichy regime of French cuisine, and Freudians consider "psychrometric" an invasion of their stranglehold on epistemology.

Along comes this Hungarian, Victor Olgyay, and saves us by making another kind of thermal comfort chart, as shown above. Notice that it is written in Spanish, so it will not be understand by Americans. I've plotted a couple months of Bangkok weather on it, so you can see how justified you are in just turning on the fan and relaxing, because you are at the limite de trabajo while still safe from a golpe de color.

Banish unsightly necksweat!

One of the thermal challenges in hot-season Bangkok is sleeping comfortably without air conditioning between bedtime and about 2 am, when things finally begin to cool off. With temperatures remaining in the low 30s, the body cannot pass off its 100 watts of heat to the environment by convection, especially if one is sleeping on a fahlang-style mattress and using a fahlang-style pillow. So sweat begins, and soon enough you are lying on a disgusting wet pillow that is hard to dry. Your head, with its ample blood supply, becomes especially sweaty.

It never would have occurred to me, even after watching the natives, but a guy on Soi Cowboy told me that fahlangs are overly attached to their sleeping apparatus, fluffy pillows and soft mattresses, but the fact was that in a few nights they could get used to the local way, hard pillows and sleeping on concrete was no serious inconveneince once you got used to it.

So I replaced the fahlang pillow for a few nights with this smaller hard thing. He was right, I was more comfortable the first night, with air circulating nicely around my neck. Assuming that I am evaporating half a can of Singh every hour, 90 grams at 2500 joules per gram heat of vaporization, I'm picking up 60 watts of cooling. Good for my blood pressure, too!

Next challenge: go all the way, sleep on a wooden pallet which is the Thai tradition.