Portable Evaporative Coolers (known simply as air coolers) are designed to cool larger areas where conventional portable air conditioning is either not suitable or is financially impractical, not least because they use only a tenth of the power of a refrigerative portable air conditioner. They are best used in workshops, warehouses, large shops and department stores. Indeed, they are ideal for any work space with good natural ventilation such as open doors and windows, whereas refrigerative units can only be used in a “closed air” environment. Evaporative Coolers operate on the very basic scientific principle of sucking ambient air through a wet filter (the filter in the case of air coolers is a purpose-made honeycomb structured pad) and the temperature of that air once it has passed through the filter is dramatically lowered. The actual temperature drop is dependant upon how humid the air in the room to be cooled is.
The large tanks in the air coolers are filled with water and an internal pump draws the water to the top of the filter pads keeping them totally saturated. The fan sucks air through the pads, lowering the temperature in the process.
The concept of evaporative cooling was first discovered by the Romans. They used to hang wet blankets over the roofs of their houses and when the wind blew through the blankets it significantly cooled down their homes. Modern-day air coolers work on a more advanced version of this exact same principle!
Many people do not realise the effectiveness of just cooling with water and the energy savings of evaporative cooling over refrigeration cooling simply can't be ignored. Perhaps the best way of describing how evaporative cooling works is by imagining yourself standing on the beach with the breeze blowing across the water. The air collects moisture which then hits your body giving that nice ‘sea breeze’ feeling. Or, when you come out of a swimming pool on a hot day you immediately feel cold before towelling off. This is simply the water on your body evaporating and a by-product of evaporation is cooling. Evaporative Coolers have very powerful fans so please be mindful of this when choosing which model is best for you. They are unsuitable for offices, unless you enjoy the sight of your most important papers flying around the office!