|Brazilian Volvo N10 with an evaporative cooler. The black box behind the side ladder is a water reservoir, while the roof-mounted white one is the evaporative unit.|
Basically, there are very few options for those who don't consider getting rid of some sort of cooling device in their vehicles. An option which already went quite mainstream is evaporative cooling, which got favored by many truck drivers in South America (most notably Brazil, Argentina and Uruguay) due to the ability to remain operating after the engine shutdown, since it doesn't rely on an engine-driven compressor to perform its duty. Actually, has no compressor at all... Its operation is all-electric, but it doesn't put a significantly greater charge over the electric system than a simple forced-ventilation device would do...
|Evaporative coolers are cheap and easy to retrofit even into older vehicles, such as this Mercedes-Benz L-1113|
Another advantage is the purchase cost of an automotive evaporative cooler (often quoted in the United States and Canada as "swamp cooler"), which is on average more than 2 times cheaper than a regular air-conditioneer. Depending on the size of the vehicle's cab, the cost advantage can get even more favorable for evaporative cooling...
|Brazilian Volkswagen Transporter (Kombi) fitted with 2 evaporative units: cheaper than an air-conditioneer and doesn't overload the underpowered 1.4L EA-111 flexfuel engine...|
The operative principles are also different: an average air-conditioneer works thru the compression of a gas which circulates inside a set of metallic serpentines, leading to a partial condensation of the air humidity inside the refrigerated compartment, and subsequently the condensed water gets expelled to the outside. It's worth to note the dried air is often pointed as a source of respiratory nuisance. Meanwhile, an evaporative cooler has water directly sprayed into the air. The water ends up evaporating due to the heat absortion. A set of texturized filters avoid any ocurrence of dripping, in spite of the increasement on the air humidity.
|This coach, fitted with air-conditioneer, has sealed windows, avoiding the passengers to keep them open.|
In spite of the purchase and maintenance costs advantage, evaporative cooling has only two major disadvantages: its efficiency slightly decreased when the ambient relative air humidity is already high, and it can't provide heating autonomously. But after a detailed case study, pointing out the pros and cons of the operational scenarioes, evaporative cooling can be revealed as the best option for many customers.