Green Architecture: Using Water to Cool Your House
Somebody sent me this article about a man in Albuquerque whose property is nearly sustainable. His philosophy is to work with nature, not against it, and I am completely in agreement with that. I think we get ourselves into more trouble by manipulating the elements and forces around us. If we are living with the planet, as my Soils Science teacher said 33 years ago, we’d struggle less, accomplish more, save resources, and cut our energy bills.
I love everything about Paul Lusk’s property, from the reed-filled marsh for treating wastewater (I wanted to do this when I bought my house 15 years ago!), the conveniently placed compost pile, and his homemade electric truck. But I especially like the way he cools his house.
This is not a new idea to me. Here in the arid desert, mobile homes are best cooled with swamp coolers. The dry outside air is pulled through a mechanism filled with water, which adds moisture to the air, which is then blown into the house. The best way to get a swamp cooler to work is to leave a window cracked open to create a convective flow. Aside from an adobe home, a swamp-cooled trailer is one of the coolest buildings I’ve ever been in!
If you grew up in the southwest desert in the 1950s (or maybe your parents did!), you are probably familiar with the water bag for cooling cars. This is the same principle. A bag of water was hung on the grill of a car. When the car was moving, the hot desert air was pulled through the water, and the cool air kept the engine from overheating.
Greenhouses also utilize evaporative cooling. There is a pad or series of pads on one end, and water is pumped into them. A fan on the opposite end of the greenhouse vents hot air out, and in the process, pulls outside air from across the wet pads. The water cools the air as it enters the greenhouse, dropping temperatures by at least 10º.
The cooling tower
Paul Lusk, who taught architecture at the University of New Mexico, used the evaporative cooling concept for his home by building a cooling tower. It is a tall, square chimney, and the top section has water-absorbing pads on all four sides. Hot air from the house rises up the tower, the water cools the air by adding moisture to it, and then the heavy, humid, cool air drops back into the house.
Warm air rises, because it is lighter than cool air, so naturally the cool air sinks back down the tower. It is a constant cycle of air movement and cooling. You have to have some way to cool your house in central and southern New Mexico, because temperatures hover in the high 90s and low 100s most of the summer. I’m sure most houses in Albuquerque have air conditioning, but Lusk does not!
Water can also be used in more humid and tropical climates. A large water feature, such as a pond or swimming pool, can be placed next to the home in the path of the prevailing winds. The cool, moist air over the pool would be carried into the lower level of the house. Hot indoor air would be vented out high windows (hot air rises, remember?) and replace by the cool air. Think about it. Coastal homes or those on lakes are always cooler than landlocked homes.
Apply evaporative cooling to your next remodel
Think of using water to naturally cool your home next time you build or when you remodel. Like Lusk says, engage with your environment, be responsible with resources, and improve the system as a natural consequence.