Cooling Options, Part One

Cooling Options, Part One

After I brainstormed a list of cooling options, it appeared to me that they fall into three broad categories – the environment that surrounds you, personal habits that can be adopted, and methods of cooling the body itself. Somewhat like moving from a macro to a micro scale.

Broadly speaking, the environmental category has much to do with your shelter choice. The first is geography. If you hate heat and humidity, you may not want to live in the Southeast US. Likewise, if you detest any kind of heat, both the Southwest and Midwest are probably poor settlement choices. I choose to live in the more northern latitudes in large part (but not entirely) due to an aversion to heat. Higher altitudes also have the same general effect. (There is a conversion between altitude and latitude, but I don't have the specific numbers off-hand. A quick Google search indicates one potential conversion rate is 1000' of altitude is equivalent to 300 miles of latitude, but don't bank on that without further research.) Such a move need not even be permanent – many people migrate seasonally. Retired “snowbirds” are usually the first to come to mind, but it wasn't all that many decades ago that mother would take the children to a summer house during the school break, with father joining them on the weekend. Many American Indian tribes had similar seasonal nomadic tendencies – summer fishing camps and winter hunting grounds. (This is one of the countless reasons Indian reservations were a foolish concept.)

In a permanent residence, cooling considerations used to be, and still can be, critical design elements. The courtyards of the Middle East and Mediterranean are designed to provide open yet shaded areas. The decorative grillwork on windows allowed light to enter, while limiting direct solar gain. Thick masonry walls changed temperature much more slowly than thin modern ones. Sometimes this can backfire however, as seen in Chicago's brick bungalows. Once they heat up, they tend to stay hot, leading to unnecessary deaths during periodic heat waves. Another building options is sizing the roof overhang or installing shade canopies. The main house of the property I live on uses a couple of these techniques – the thick concrete block walls resist penetration of summer heat, while the roof overhand was calculated to block the high summer sun while inviting entry of the low winter sun. There is a drawback to this fixed system, however – the concept of Thermal Lag.

Thermal lag refers to the time delay between insolation (basically sun penetration) and temperature change. We see this in the summer, when the sun reaches its maximum in June (my apologies to those in the Southern Hemisphere) but the temperatures don't reach their maximum until July or August. The same thing happens in the winter – the solar minimum is in December, but the general temperatures keep dropping into January and February. A fixed solar-blocking system can easily be calculated to limit July and August's insolation, but with the effect of also blocking April and May's, spring months where the additional solar influence may be desired. This is where adjustable systems may be preferred instead, canvas awnings for instance. These I have no experience with.

The daily, as well as annual, changes can be utilized as well. Opening up the house at night, encouraging cooling evening breezes, then closing the house during the day to retain the milder air. This is most effective in areas with significant day and night temperature changes. I'm always surprised more people don't do this, but it does require more awareness and action than simply setting an AC thermostat. I for one enjoy taking an active role in my environmental management, of feeling aware and connected to the world around me.