Beat the Heat

Every summer I Google my way through every variety of heat-relief so far invented, searching for the magic bullet i.e. the super-cheap way to have the house cold enough to use as a meat warehouse. There are some clever suggestions out there. For example this year I tried bubble wrap double glazing, which cost next to nothing and has turned the front room, normally a fair approximation to a furnace, into something almost pleasant. You just spray mist a bit of water onto the window, and the bubble wrap sticks right to it, and stays there. And then it just peels off if you want to remove it, and you can re-use it for years. 

But this year while sampling the goodies online, it occurred to me that maybe if you change your point of view, in the literal spatial sense, this problem takes on a completely different look. (I'm leaving out for now the option of self-hypnotising yourself to feel deliciously cool. Quite a simple thing to do actually.) One technique many use is to soak a t-shirt in cold water, wring it out and then wear it. Synthetic fabric works better if you're bothered about clinging. This works amazingly well, and it's little wonder - you're cooling directly on your body. 

So last night I was sitting working, enjoying the cooling t-shirt, and it suddenly occurred to me that maybe the whole idea of 'air conditioning' is a bit arse-end about. The whole assumption, of the need to condition the air, is a peculiar one. In most cases it's actually just us that we want to keep cool, we couldn't care less if the books on the shelves, or the ceiling, or the lounge is bathing in cool air. But we use huge amounts of energy cooling the whole shebang, every last cubic millimetre of the room. Would we take a completely different approach to the heat if we narrowed right down to what it is we actually want - to keep us cool? Just us, that small, tiny fraction of the volume of the room. 

This is what the wet t-shirt does (yes yes, cheap jokes to be had here by the wheelbarrow-load). You can supplement it with a wet bandana draped around the neck, and/or more wet cloth on the wrists, or even soaking your feet in a bucket of cold water. All of it cools you dramatically, is simple to do and uses no energy, and very little water. Heck, just run the bath full of cold water and dip in and out of it during the day, when you start to feel the heat. Leave the same water in there, unlike normally the fact that it might lose heat is actually a bonus. 

More generally I wonder if the whole thermodynamic cycle approach we take to heating and cooling (see an earlier entry about Serres) is unnecessarily wasteful. It sort of assumes that heat is the opposite of cold, and expends huge amounts of energy changing one into the other and back again. We live thermodynamic lives, not just in our heating and cooling but in the booms and busts of economies and psychologies (manias, depressions). We're addicted to that cycle (the Carnot cycle, if you want to look into it in detail). Take a look at vortex tubes while you're at it for a glimpse of something quite different - the ancients made the vortex the centre of their rejection of the thermodynamic cycle, but we didn't understand why for a long time. We still don't fully, and the fact these are portrayed here as brilliant but 'inefficient' says to me that we're only scratching the surface of what's really going on.