Carrier's Magic Chart

Air Conditioning engineers trace the decline of US-French relations to the popularity of the chart which was invented by the American patron saint of aircon, Willis H. Carrier. Carrier's so-called psychrometric chart replaced the beloved French Mollier diagram, marking the end of French superiority in science. Sigmund Freud was fascinated by the chart, which he mistakenly thought quantified the human psyche (misreading psychrometrics as psychometrics). However, after discovering his mistake he thought it soounded like a good idea anyway, and went on to develop his concepts wherein he substituted libidinous pressures (The "Id") for vapor pressures.

For those readers who are seeking a little more rigorous discussion of Bangkok weather, I am taking a break from roofs and such to put the recent weather, which we see here as red and green points, in the context of the Carrier chart (basics of which you can look up in Wikipedia if you are really curious).

What I do here is trace the natural history of a cubic meter of Bangkok air which you might find around, say, Benjasiri Park at 6 am when folks are out there doing Tai-Chi and aerobics. The moisture, temperature, dew point, and enthalpy of the air at 6 am is shown as the starting point of the day's oddyssey. The wet bulb temp, ie the temperature of all those dewy flowers across the street at Villa supermarket, is about 24 C, and the enthalpy (ie energy) is a little over 70 KJ per cubic meter. With a relative humidity of about 80 percent, those joggers are going to start to sweat pretty quickly.

It always struck me as curious that the Bangkok air does not change its energy content much over the day, by afternoon it's a lot hotter but a little drier so energy is much the same. But look what happens to that air if it is lucky enough to get sucked up in the Emporium air con engines which blast off at about 10 am. This air will be cooled down to its saturation point (ie the dew point) and then with further cooling dump about half of it's moisture, so that the nice icy feeling you get when you go into the mall is your own dear sweat getting sucked up by this dry hungry air. It's not the air that's so cold, it's your own vaporizing sweat!

We can look ahead with delicious dread at the daily cycle at the peak of the hot season in early May, shown in red away up on the diagram. For all those Buddhists out there, lots more suffering to come!

The colored zones on the chart are so-called comfort zones, green where everyone is happy, yellow where some fahlng experts say folks in "undeveloped" tropical countries should be happy (so they don't use so much of that fuel meant to fire up big SUVs). Everyone is unhappy in the red zone.

Nice going, Emporium, I think we'll all go shopping!