Evaporative Coolers, and making your own cool air

Last year there was a popular posting about making your own air conditioner. The idea was to run pipes through a bowl of cold water (perhaps with ice), and weave the pipes inside a normal house fan. Turn on the fan and it blows across the pipes exchanging heat and cold, cooling the air, and voila your house is cool. I started to try the idea myself, wasn't able to get it to work, and I even tried a different version with hanging a cloth in a bowl of water.

A similar idea is the swamp cooler, or evaporative cooler. This is something which does work, in certain climates, and is quite popular in desert areas. It's the same idea, evaporation of water cools air and you can harness that to cool a house.

I live in Silicon Valley, and have bought a low end evaporative cooler, and found that it works fairly well.

I want to go over the principles and resources available on the Internet.

Evaporative cooler (Wikipedia): Gives a good overview of the several types of evaporative coolers. They clearly say the system works best in dry climates, and only so-so in moderately dry climates.

Evaporative Coolers: Whole-house cooling in arid regions at a low first cost Has another in-depth survey of this cooling technique. An advantage they mention is the ability to cool without using refrigerants such as chlorofluorcarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), that can harm the ozone layer. They have another page on two stage evaporative coolers. In the first stage of a two-stage cooler, warm air is pre-cooled indirectly without adding humidity ... In the direct stage, the precooled air passes through a water-soaked pad and picks up humidity as it cools. Because the air supply to the second stage evaporator is pre-cooled, less humidity is added to the air

The Energy Efficiency and Renewable Energy Consumers Guide has another good overview of evaporative cooling. As does the Phoenix city government.

Home Energy Magazine has a more technical article, that includes a U.S. map showing the likely areas where evaporative cooling would be best. And there's another at lbl.gov.

Air Conditioning: "We're cooking our planet to refrigerate the diminishing part that's still habitable"

In The deluded world of air conditioning William Saletan offers a very interesting perspective. "We're cooking our planet to refrigerate the diminishing part that's still habitable".

When you air condition a building you're taking heat that's inside the building and moving it outside. That's what an air conditioner is, a heat pump. The fluids that go through an air conditioning system? They're the medium through which heat is exchanged, or rather pumped, from one place to another.

And, when we pump heat outdoors that costs energy. The energy used comes from somewhere, most likely through burning natural gas. So when we run an air conditioner and pump energy outside, that natural gas that's burned to make the electricity emits carbon into the atmosphere, which then in turn increases the greenhouse and global warming effect.

Air conditioners hasten global warming. So it's a fools journey to run an air conditioner because when you do it's just tightening a noose around your neck. Unfortunately the tightening of that noose is happening slowly enough that it's hard to connect the air conditioner with the global warming.

And, it's not just air conditioners. It's the whole range of gadgets that use electricity or gasoline. Want to clean up the fallen leaves in your yard? Are you going to get out a rake, or use a leaf blower? Want to go grocery shopping? Are you going to drive a Hummer or a Geo Metro or a Neighborhood Electric Vehicle (NEV) or a bicycle? When your teenager turns 16 do they get a car immediately? Do you know what a "phantom electrical load" is?

In this hot summer air conditioning is a, er, hot topic. There are some alternatives to consider. But something I wonder about is, just how the heck did our ancestors survive without air conditioners?

Why do we have to use air conditioners when there are thousands of years of human experience that could show us how to live without air conditioning in the first place?

For example, there are herbal ways to cool down. Ways that do not require refridgeration or air conditioning.

In the Middle East Sekanjabin (?sp?) is a traditional drink. It's main active ingredients are mint and sugar. Both are known to herbalists as cooling substances that, when ingested, will act to cool the body.

How can you prove this to yourself? Let me offer a simple test from Healing with the Herbs of Life. First take a sprig of fresh mint, crush it up, and pop it in your mouth. Doesn't your mouth feel cool? Take a breath in and out. Cool?

Now take some cinnamon, just a dab, and put it in your mouth. Hot?

Mint is a cooling herb, while cinnamon is a heating herb. Healing with the Herbs of Life goes into this in extensive detail from the perspective of Chinese Medicine. But the concepts are known to herbalists of all societies.

Another example of how the thousands of years of human experience can show us how to cool our living quarters without air conditioning. A few years ago I visited some friends who own some land in the Sierra Nevada mountains. It was mid-summer, on a hot day. On their land is an old one-room schoolhouse that sits out in the direct sun all day long. However, the inside of that schoolhouse remains cool all day long. How? Thick walls. Similarly in California there are many old buildings left from the Spanish. These are "adobe" buildings and the main feature is the thick walls.

Thick walls mean good insulation. You might think insulation only helps keep heat inside. Actually what insulation does is impede the flow of heat. So the heat outside the building has a harder time getting inside the better the insulation.

Another alternative to air conditioning is offered by the plant kingdom. Plant trees around your house, trees that are large enough to shade the roof. The trees will keep the heat from hitting your house in the first place. If you live in a place that that gets real cold in the winter, then you want trees that shed their leaves in the fall. That way in the winter the branches are bare and the sun will reach your house to provide some heat.

Reference: The Deluded World of Air Conditioning

Other air conditioning alternatives

As I mentioned in Make your own air conditioner, I want to minimize my power use. So I'm looking at alternatives to buying another window sized air conditioner (especially as none of the stores have any in stock).

One alternative I saw was to drape a cloth in a bowl of water, and blow air over the cloth with a fan. The evaporation is supposed to make the air cool. I tried this, and it didn't make any effect.

The one thing I do find helpful is to have fans blowing air directly over my body, and to have fans blowing air in from the outside. This combination makes life bearable except in the hottest of times.

Another thing which helps is to enlist the aid of the trees. Trees naturally do the evaporative cooling effect, because that's what their function is. Trees draw water out of the ground and perspire the water through their leaves. If you sit under a tree you're in an evaporative cooling zone.

The opposite kind of zone is, unfortunately, what our cities are tending to build for us. Namely, the long stretches of asphalt. Consider, what color is the most absorptive of heat? Black. What color is asphalt? Black. Why, oh why, are asphalt parking lots to hot? It's because they're black. Do you think that perhaps the abundance of asphalt parking lots in cities might contribute to the heat in cities? Yes, they do, and U.S. government scientists did study this very issue several years ago. So why do cities like to continue supporting the installation of asphalt parking lots? HeckifIknow..!!!

There is also the swamp cooler. Swamp coolers are widely used in the desert areas, and work best with dry climates. In the SF Bay Area our humidity hovers around 50%, which is the top end of the claimed humidity range where these work. Swamp coolers work by evaporating water, so of course the more readily the water evaporates the better the cooling action. I have ordered a swamp cooler and hopefully it will arrive next week.

Make your own air conditioner

It's been hot the last few days. In St. Louis severe storms knocked out power over most of the city. In general the U.S. has had a real serious heat wave, and in England they've set another all time high temperature record. In the SF Bay Area it's been very hot for this area.

Since my interest is to see how I can live comfortably while keeping my power use minimized ... I don't have an air conditioner in my house, and instead rely on fans and one window-sized air conditioner. Okay, it's more accurate to say the house doesn't have central air conditioning. For the most part I'm uncomfortable but it's not unbearable. But I think I'm being more accomodating to the weather than my neighbors, many of whom have central air conditioning cranked to the max.

Cranking the air conditioning to the max may seem like it's helping you, but in the big picture it's only making the heat worse. The higher power draw required by having the AC maxed means the power plants are running at maximum capacity. Indeed there have been day after day where the power producers have been at emergency production levels, barely able to meet the demand with the generating capacity. That high power production use directly turns into higher levels of pollution, because most of the power plants are burning fossil fuels. Higher pollution levels mean higher degrees of global warming and heating.

Make Your Own Air Conditioner and PETE'S HOMEMADE AIR CONDITIONER and How to build a $30 air conditioner and GEOFF'S ORIGINAL HOMEMADE AIR CONDITIONING cover a low-cost low-energy-required alternative.

The idea is ultra simple. You get a cooler of ice water, and a submersible pump. Attach the pump to a hose arrangement where the hose is woven through a fan, and then direct the hose back into the cooler. Turn on the pump and the fan. The result will be to pump cold water through piping over which you're blowing air. The air should cool down while going over the piping.

It's simple enough, and inexpensive to put together. One of the pages claimed a cost of $30.

I've acquired the required parts and will be putting it together later to see how well it works. To make ice water, I've bought some of those freezable blue blocks. The plan is to freeze them, and put them in a cooler with some water. I have a submersible pump I bought to make a water fountain several years ago. For tubing I bought some plastic tubing at the pet store, and intend to, if this works out, buy some brass tubing for the heat exchanger.

The first experiment was to hook the pump to the tubing. Unfortunately the pump is not powerful enough to make water go up very high above itself. The tubing is three feet long, and the pump is unable to get the water to go the full length of the tubing if it is stretched straight up. But if you have the tubing coiled just above the pump, then water goes through just fine.

It's hot ... here's how to cool off w/o using lots of energy

We're having a heck of a heat wave this summer. I live in the SF Bay Area and the temperatures are moderated a bit by the ocean. But yesterday it was over 100 where I live, which is an outrageous temperature. I know, I know, 100 isn't so outrageous in other parts of the U.S. but in the SF Bay Area our climate is highly moderated by the ocean. Usually severe winter or summer weather is but a rumor we hear about from friends in other parts of the country.

And I was reading that England is also seeing 100 degree weather. That they were expected to set an all time high temperature. And that it's the second time in the last three years that England is recording an all time high temperature.

Anybody doubt about Global Warming?

Anyway ... this is supposed to be about keeping cool. One reason I wanted to live in the SF Bay Area is the climate. I read in a "Places Rated" book that here in the Bay Area we have a low percentage of air conditioners installed in houses. Obviously that's climate related, and any place that doesn't have the people using air conditioning has got to be relatively cool in the summer.

And, indeed, that's what we have. Usually we have moderate temperatures in the summer with only a few days where we wish we had air conditioners.

Here's a few ideas I've collected about keeping cool without using a lot of power. Air conditioners use a lot of power, and if you want to live sustainably it's worth considering other ways of keeping cool without using air conditioning.

Attic fans work to exhaust hot air from your attic. The attic is like global warming on a miniature scale. Your roof is probably black color and is probably exposed to the sun, and therefore absorbs heat that's transmitted into the attic. The attic then sends that heat into the house. But an attic fan turns on when the temperature is high, draws the air out of the attic, reducing that effect.

Keep the windows open at night when it's cool, use fans to draw air into the house at night, and then shut the windows during the day. The idea is to capture cool air and keep it as long as you can during the day.

wiki how has some tips on keeping cool

For example .. aim a fan so it blows over the top of a bucket of ice. This will work better when the humidity is low. It's a similar idea to the swamp coolers they use in the desert.

Take a cool shower .. cover yourself with a cool cloth .. wear socks that have been soaked in cool water ..

The general idea is to use evaporative cooling.