Arizona’s new heat officer said Friday that he is working with local governments and nonprofit groups to open more cooling centers and ensure homes have working air conditioners in a more unified effort to prevent another ghastly toll of heat-related deaths this summer.
That’s not air conditioning, at all.
That’s evaporative cooling, and it’s been used for hundreds of years in cultures worldwide to help reduce heat. Adding humidity into dry air naturally reduces the heat index. It’s not supposed to make it to the ground, the entire point is for it to evaporate and increase ambient humidity in the air.
It’s extremely energy efficient, but is limited to very dry environments. Above about 30% ambient humidity it quickly stops being effective at cooling the air, and at around 60% ambient humidity it’s just no longer noticeable. So for a desert area, it is an ideal, cheap and easy way to cool an area.
There are evaporative systems designed for homes and businesses that use the same principle. A box with an opening on one side for airflow, a large wet pad and a fan combined with ducting, will cool an entire home. It uses remarkably little water, and power only to run a simple pump to keep the pad wet and the fan spinning. It uses a fraction of the power and air conditioner uses and is a lot more effective when humidity is low.
For most of the summer an air conditioner isn’t even needed to cool a home. Central ducting with an evaporative cooler will work for 90% of the summer. Only during the monsoons where the humidity is too high for it to be effective is an AC system really necessary.
Source: I live in AZ and my home has both an evaporative cooler and an air conditioner.
Yup. Evaporative cooling was popular in AZ before electricity was available. In the late 1800s to early 1900s there were many homes and building with cooling towers on them. People would hang wet sheets across them and the cooling effect would create a current as it fell down the tower which would on turn create more draft across the cooling cloth.
Do you have separate discrete units to pull that off? Or are they both tied into the same air circulation system?
Discrete units but both attached to the same ductwork.
Since A/C needs to operate on a closed system there’s a one-way damper just below the Evaporative cooler where it attached to the duct work. The evaporative cooler on the other hand works best in an open system, so you can direct airflow best by opening windows in rooms that need more cooling.
Two separate controls as well. The A/C is attached to a standard thermostat. The Evaporative cooler is simple by comparison, just a manual knob with Off, High Fan, Low Fan, High Cool, Low Cool, and Pump only. The last three run the pump to keep the pad wet.
At night, Low Fan might be all that’s needed even in the summer, just moving air. The cooler moves A LOT more air around the house than the A/C does since it has a massive spinning drum fan and an open airflow system.
That’s a clever arrangement! Thanks for sharing. I’m in Colorado and we get dry enough that evaporative cooling is effective, but home came with AC, which means everything just gets dry and you static shock all your electronics to death as your power bill spins up to infinity. I never considered that one could have a dual system to switch between. What is your temperature differential with the evap operational? 20 degrees or so?
Yeah about 15-20 normally, but can get up around 30 around peak summer with zero humidity. Above about 100 outside though it just can’t keep up and the AC is needed even with low humidity.
So basically above 100 and above about 40% or so humidity, the AC is needed, otherwise the evap cools better and is a lot cheaper to run.
I meant “like” as in similar to, not as a filler word. I know they’re not air conditioners. I was likening the design for descriptive purposes for people who live in less arid regions. It was especially surprising to see them aimed outdoors when I visited. When I asked a shop attendant about them, he said they were to keep tourists from passing out because they drink too much alcohol and not enough water. Haha