You probably don't want to place your Netatmo outdoor module where it will get direct sun. This yellow anomaly below is caused by direct morning sun for and hour or two on the outdoor module, and probably to a lesser degree from heating of the dark brown soil on which the module is set in this case.
Poor location! Better put the module out of the sun and on a less heat absorbing surface.
Are Bangkok and other tropical cities on a path to heat doom? New Netatmo-acquired data from the front lines of global warming, and new ideas on how to live with it -- even without air conditioning.
Friday, March 24, 2017
Tuesday, March 21, 2017
Radiant heat: invisible but deadly
On a warm afternoon with full sun a darkish thin surface (such as a metal roof or a tile roof) heats up to 50 degrees C or more, with the heat being almost immediately transferred undiminished to the underside, as you can see from the temp reading of the underside of this rubberized canvas tent which is supposed to provide cooling shade, but really provides heating shade, which will radiate on the order of (52-32)*5=100 watts per square meter to your head, plus perhaps as much again convected to the air below. Not as bad as the 700 watt sun, you might say, but not comfortable either – and suffocating if the underside of the roof is not radically ventilated. So next time you are sitting under one of these tents at a Thai wedding or funeral, be warned -- it's the heat, not your emotions, that is causing you to feel like you are going to faint.
Here is an excerpt from the manual of the Australian company Bluescope Steel who make (and promote) steel roofing in Thailand. This indicates a reduction in heat transmission through thin roofs (steel, cement tile, etc) if they have foil insulation, properly installed (air space above and below foil, and foil with shiny side down.) For a dark roof, the thermal transmission is said to drop from 165 to 22 watts, almost 90 percent. But I can say from my own experience that there are many qualifications to this supposed effectiveness of thin foil, more specifically that bubble-backed foil that comes in rolls, to be discussed later with a real example.
Sunday, March 19, 2017
Hot Season brings miserable hot wet wind from the sea
Much like the Texas Gulf, onshore hot season wind smothers Bangkok with heat and humidity. Even at the coolest time of the day the saturated air from the gulf to the south is close to 29C (surface sea temp, red), so sweat at body temperature will provide little cooling.
Saturday, March 11, 2017
Old time hot days in Boston
From the free download chapter |
Friday, March 10, 2017
My Thai wife in her bedroom not minding 29 C (84F)
Generally I have not put much credibility on theories of racial differences for thermal comfort. My Thai wife's comments, sweat thresholds, and complaints are very close to my own. But as the hot season closes this year in I notice that I am turning on the aircon every night when the temp hits about 29 C (84F). She is not. Be interesting to see when she does.
Wednesday, March 8, 2017
My Netatmo readying for the coming blast of heat
With seriously high temperatures last week forcing me to turn on the aircon for sleeping, I ready my Netatmo system for the expected record blast of heat next month.
Hot season relentlessly moving in. New records for Bangkok?
@Netatmo @dickmeehan Checking out my Netatmo gear for the coming heat. Perfect performance to date, looking forward to recording rich data in and outside my Bangkok condo tropicalcool.com
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