
After of weeks of cloudy days and sporadic rain showers, we are in a heat wave. While we have air conditioning, it’s a bit of a to do. There is an independent, rollaway device with a large hose that you pop out the window; it cools and takes the warm air out. Good for one room. We air out the apartment in the early morning, but not too long. We watch for mosquitoes, and have set up mosquito traps. We also have room fans. So I cannot really complain too much. I had thought that the thick stone walls would help keep things cool, but on the 4th floor, its not working as well as on lower floors. The best place to hang out and cool down is a church.
I was wondering whether I could use the room fan and apply evaporative cooling concept to help lower the temperature in the room. The basic idea is when water evaporates, it absorbs heat from its surroundings. This is because converting liquid water into vapor requires energy — that energy is drawn from the environment in the form of heat, which lowers the temperature of the surrounding air. Similar to sweating, the moisture on your skin evaporates and cools you down.
I had read about how ancient Egyptians had used this idea. Using wet reeds and cloths in a doorway or window, the hot dry air would pass through it and water would evaporate and cool the air. They also had leaking pots, that would slowly leak water on the wall, as well as had servants fanning water vessels to increase the airflow over the wet surface, enhancing evaporation.
Modern evaporative coolers or ‘swamp coolers’ work on the same principle. They are less energy demanding, cost effective. I remember trying to understand this when years ago, the swamp cooler at work years ago failed, and the tech was trying to explain to me why.
Evaporative cooling works best in dry, heat. Unfortunately, I think it’s too humid here.
In humid climates , circulating the air and removing the heat works better. Raised floors with circulation underneath, shade, cross-ventilation seem to work better – and of course, air conditioning. There is something called desiccant cooling; essentially a silica gel-like thing pulls the moisture out of the air, then evaporative cooling is used.
Hope this heat wave doesn’t last too long, or I’ll be in church a lot.















