The whole US is currently experiencing a massive heat wave, but we seem to be getting more than our fair share of it down here in Texas. The heat in our shop’s been almost unbearable as the outdoor temps have rised to over 100 degrees F every day this week. (We even hit 106 one day.) We went in search of a way to take the hurt out of the heat and ended up trying out one of AdobeAir’s Mobile MasterCool series portable evaporative coolers.
All coolers work by transferring the energy from the hot air to somewhere else or converting it to some other less-annoying form. In normal household A/C units, a coolant such as Freon is used in a closed system, sapping the energy from hot inlet air to evaporate the coolant, then releasing the heat outdoors as the coolant re-condenses.
Evaporative coolers — or “swamp” coolers as you may have heard them called — work on the basic principle of cooling by the evaporation of water. Evaporative coolers are very simple machines. They consist of a fan which draws hot inlet air through an “evaporative pad” — a piece of porous material which is constantly soaked with water via a pump and reservoir. Energy is removed from the hot air as it evaporates the water.
As with all coolers, the heat must go somewhere. Unlike closed-system Freon-based units where the heat is “moved” to another location, evaporative coolers simply blow out the resulting water vapor along with the cooled air.
This leads to the basic limitation of evaporative coolers: the source (inlet) air must be dry enough (low enough in humidity) to allow for evaporation. If the water in the evaporative pad can’t evaporate, no cooling occurs.
This means that the more humid the air is around the cooler, the less cooling it’ll provide. If you live in a very humid area such as Florida or Houston, you’re going to see far less performance from an evaporative cooler than you will if you were to live in, say, Arizona. It also means that you can’t use an evaporative cooler in a sealed-off environment. As the cooler operates, it’ll continue to add humidity to the air until the air is too humid to allow evaporation — at which point it’ll cease to cool.
With this in mind, read on to take a look at the MasterCool MMB12 — one of AdobeAir’s mobile “spot” coolers.
Continue reading »