Advantages of evaporative cooling in cash-transit vans

Brazilian armored cash-transit van, based in a local derivative of the Mercedes-Benz Vario, with 2 roof-mounted evaporative coolers

Evaporative cooling, altough having its effectiveness more restricted when the air natural humidity goes higher, still has some advantages that makes it figure as a good way to improve thermal comfort in vehicles when a regular air-conditioner is either expensive or hard to set properly. Currently, in Brazil, it's even more popular for some special applications such as cash-transit vans than a conventional air-conditioner, mostly because of the fuel savings it can provide.

The roof-mounted conventional air-conditioner in this cash-transit van (Volkswagen frame with AutoLife body) takes more space than a set of 2 evaporative coolers, requires an amount of engine power to operate and is also heavier.

Taking this operational scenario for a case study, we might remember the effects of extreme temperatures in the health of the operators: during the summer, the internal temperature of a cash-transit van can easily reach 50°C/122F, and the poor air renewal inside the cabin ends up leading to phisycal and mental fatigue, blood pressure alterations, skin allergies, eyes dryness and respiratory distress. Meanwhile a regular air-conditioner requires the engine on to activate the compressor, evaporative coolers (also referred to as "swamp-coolers") can operate as stand-alone units in electric power only, and some are programmable to pre-set a comfortable working environment for the crew.

Even the Spanish-based Prosegur, one of the world-leading cash-transit companies, runs evaporative cooling on its Brazilian fleet, also extending the benefits of this setup to some of its other South-American branches, most notably in Peru and Uruguay

The maintenance of an automotive evaporative cooling device is also easier to perform, requiring basically the water fill-ups (more frequent than recharging the refrigerant gas of an A/C, but still an easier and safer procedure), periodic replacement of the humidifier filters (usually at each 3 months) and eventually the replacement of the fan electric motor or its brushes. But since the roof-mounted evaporative coolers are more self-contained, access to the components for the preventive maintenance is quicker, leading to a reduced time to be spent with these procedures, while an A/C requires sealing tests for leaks with an UV reagent for visual contrast, compressor driving belt and electromechanical clutch pack replacements, and in extreme situations may even require the dashboard to be disassembled.

Comparing to a regular air-conditioner, the effect of an evaporative cooling setup over the fuel consumption is more negligible, not just due to its ligther weight increasement but also due to the lower mechanical load, since it doesn't require an engine-driven compressor. Instead of using a synthetic gas, it uses only water as the cooling fluid, which also reflects as an environmental benefit since the most usual refrigerant gas commercially available is HFC-134, also known as R-134a, ranked among the so-called greenhouse gases and with a lifespan longer than carbon dioxide when released in the atmosphere. And meanwhile R-134a requires an energy expense to be manufactured, evaporative coolers can use rainwater.

The Brink's Company uses rainwater collectors in all its Brazilian branches

4-cylinder Diesel engines: the best response to the claim for better fuel-efficiency in trucks

We all know Americans love trucks, and they also have their loyal enthusiasts in export markets. A good example is the Cadillac Escalade EXT, which offers a good balance of luxury and heavy-duty capabilities. There is, however, a significative downside regarding those vehicles: the fuel-efficiency is compromised by their size and weight..

Usually, massive V8 gassers, or eventually flexfuel, are the most usual engine option for an American full-size truck, altough other options could also provide a fair performance with improvements to the fuel savings. I can't deny my favorite choice are Diesel engines, due to their higher thermal efficiency, adaptability to alternative fuels, and also because they're cool too. With the right gear ratio selection, even some 4-cylinder turbodiesels, with a displacement considerably below the 6.2L of the currently-offered V8, can be a good match to an Escalade while not feeling underpowered at all.

Many commercial trucks with a GVWR that often doubles the Escalade, such as the Isuzu NPR, are available with engines ranging from 3.0L to 5.2L, and still leave a good safety margin for towing in case of engine swap...

It's worth to remember the technical evolution regarding Diesel emissions aftertreatment, which can lead to an end to the misconceptions pointing these engines as "filthy". At the long run, they're even cleaner than a comparable gasoline-electric hybrid driveline, not just due to the lower energy spent to manufacture a Diesel engine but also the lower amount of raw materials in opposition to a complete hybrid setup with the electric motor, additional electronic controllers and the traction battery pack.

Mercedes-Benz 240D: features one of the most dependable engines ever made, but had its limitations regarding performance and acoustic comfort

Another feature that evolved significantly in the 4-cylinder Diesels is the acoustic comfort. A good example is Mercedes-Benz: its earlier Diesels still used to clatter a little even tough the indirect injection makes it less noisy, and also used to feel quite underpowered comparing to a gasser in spite of the increased fuel-efficiency. But nowadays, with turbocharging and advanced electronic engine management, even the flagship S-Class is available with a 2.1L 4-banger Diesel. The common-rail injection, due to the multiple jets for every injection cycle, improves the sound deadening and also makes the engine run smoothier.

Often, the unavailability of Diesel versions for some SUVs, like the Chevrolet Suburban, is pointed as a prejudice to increase their global presence, altough some enthusiasts claim that only a huge V8 can lead to the genuine American "soul" into them. That perception of the amount of cylinders as a premium feature is quite dumb, since it also increases the internal frictions inside the engine, decreasing its efficiency...

GMC 6-100/6-150: Brazilian equivalent of the 3500HD

However, even when there is a Diesel engine available for an American truck, it's usually bigger than it's really necessary for many operators. Okay, it can be cool to have a massive Diesel V8, but often a 4-cylinder can already get the job done. For example, the GMT400 trucks had the IDI boat-anchor 6.5L V8 turbodiesel available in North America, meanwhile its Brazilian counterparts were available with a 4.0L 4-cylinder Maxion S4T and a 6-cylinder MWM Sprint 6.07 TCA, both featuring direct injection. Not every truck buyer requires a torque amount greater than what a gasser V8 is able to provide, but the RPM bands of a Diesel are desirable even if it's a 4-cylinder, like in a walk-thru van.

Nowadays, it's no surprise that 4-cylinder turbodiesels are getting an increased popularity even among the hot-rodding folks, most notably the Cummins 4BT, which can develop over 200hp for relatively cheap but, altough these power figures can sound unimpressive, the high torque and the lower fuel consumption than a comparable gasser are a premium.

In many markets, 4-cylinder turbodiesels nearly eliminated 6-cylinder and V8 gasser trucks. One of the most notable cases is the Land Rover Defender. It was available with the Rover 3.9L V8 gasser until '97, and after the demise of this engine there were versions fitted with the BMW M52 2.8L straight-6 catering to the South African market until 2000. Since then, however, there is no gasser Defender and, after the demise of the 2.5L Td5 (5-cylinder turbodiesel) in 2007 due to emissions regulations, the only engines available for the Defender were 4-cylinder turbodiesels shared with the Ford Transit van, being a 2.4L until 2012 when a 2.2L replaced it also for emissions-related reasons.

In Brazil, for example, in '97 the Ford F-1000, local equivalent to the F-250, was available with a 2.5L Maxion HSD in a 2WD version, altough it was phased out for the following year. The 300cu.in. (4.9L) straight-6 was available for the 2WD F-1000, but wasn't so popular. In the 4WD F-1000, the 4.3L MWM X10 was the only option, mostly favored for its ruggedness in harsh environments.

In a worldwide base, 4-cylinder Diesel engines have been regarded as an effective balance between capability and fuel-efficiency. Even in special applications, such as ambulances.

Mercedes-Benz 710, Brazilian latest equivalent to the European Vario: its latest version was fitted with a 4.0L OM-364LA 4-cylinder turbodiesel, which torque rating is insignificantly lower than a Vortec 5300

After all, there's no need to be afraid of a 4-banger Diesel, it won't make a full-size cutaway van less reliable or an Escalade less luxurious.

Is it worthwhile to have an utility trailer?

In many circumstances, an average light-duty car is not enought in matter of cargo volume without compromises to the passenger space, but not everybody is willing to get a truck or could afford to deal with its higher operational cost to be used only a few times at its full capabilities (or at least closer to that).

Then, an utility trailer can be considered a viable alternative to deal with unfrequent hauling needs due to its versatility, but it's important to also consider its effects over the handling and the maintenance cost. It's not unusual for trailers with a gross weight until 700kg to not feature brakes, and to be fitted with live-axle leaf-spring suspension (often without shocks) and small 13" tyres, cheaper to replace that truck tyres.

Even considering the cost of the tyres for both the trailer and a compact car, it can remain cheaper than a set of 4 truck tyres.

Utility trailers, altough not classified as a vehicle, are usually required to have their own title and license plate.

Another favorable argument to an utility trailer is when the load can damage the pickup bed. It's particularly more critical in a modern coupé-utility, such as the Chevrolet Tornado/Montana/Opel Corsa Utility, which unibody layout makes harder to replace the body panels without compromising the structural integrity.

It's also important to consider the extra loads over the pulling vehicle's stock brakes, engine and driveline. Common-sense is recommended to ensure the trailer wouldn't compromise too much the overall safety and the durability of the vehicle, which could turn the budget aspect less favorable.

When it starts to become overkill, the problem is deeper than the anticipated replacement of tyres and brake pads, even the transmission can be severely damaged in a light-duty vehicle depending on the trailer's gross weight and the terrain conditions. A bloke who sells fresh coconut water at one of the parks of my hometown told me he once ruined the transmission of a Fiat Uno hauling coconuts with a trailer, since it had to retain lower gears with the engine at higher revvings for longer periods due to the excessive load...

So, as long as the limitations of the towing vehicle are respected, an utility trailer can be a cost-effective way to conciliate hauling capacity with money savings that a truck couldn't provide.

Evaporative cooling: a low-budget yet energy-efficient way to improve thermal comfort in motor vehicles

The cost added by an air-conditioneer to an automobile goes beyond the retail price. During the vehicle's lifetime, the comfort charges its fare. Apart from the usual increasement on the fuel consumption, since usually the compressor is driven by the vehicle's own engine, also sacrificing the performance in certain occasions (most notably in vehicles with smaller engines, of course), a regular air-conditionner for automotive applications also implies a few more procedures to the maintenance routine, due to items such as belts and pulleys required to drive the compressor, and eventually some recharges of the refrigeration gas. A few decades ago, the most usual refrigeration gas was the CFC (Chlorine - Fluor - Carbide), also known as Freon, which is regarded as an environmentally-harmful compound due to its effect to the ozone layer, and there are still some older vehicles operating with this gas instead of the HFC-134a currently prevalent.

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

Considering some special applications such as hybrid-electric vehicles, like the Toyota Prius and the Chevrolet Volt, developed under a specific goal on energy-saving, the evaporative cooling is even more worthwhile. Due to the air-conditioneer of those models getting an electric-driven compressor, allowing it to remain operating when the internal-combustion engine is off, the loads at the electric system are significantly increased. An evaporative cooler has a lower energy expense, which seems to make more sense regarding a "clean" vehicle...

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.

It's also worth to remember that a regular air-conditioneer has its efficiency decreased when there is too much external air flow entering, while an evaporative cooler actually works more effectively when there is some external air flow. This ends up leading to some advantages for this setup, due to the health benefits of a higher ratio of air renovation inside the vehicle.

Brazilian metropolitan transit articulated bus, with a 210hp engine. Too underpowered for its size and weight, but even though a regular air-conditioneer wouldn't be the most suitable solution, it's not so hard to retrofit an evaporative cooling setup. The most usual evaporative units can easily bolt into the roof hatches...

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.

Motorcycles: the most environmentally-suitable vehicles for Diesel-haters

Motorcycles are a kind of love-or-hate thing, usually bashed for the absence of comfort features or weather protection for the user, and lack of cargo space, making them unpractical to haul bigger objects. Their low fuel consumption can become appealing for people who hate Diesel-fueled cars, alongside the hybrids. But, considering the environmental aspect, the motorcycles make way more sense than a hybrid econobox, i.e. a Toyota Prius.

One of the main arguments towards hybrids, apart from the "motorcycle-like" lower fuel consumption comparing to an average non-hybrid econobox, was related to the permission to use it in HOV lanes even when the driver was forever alone. This benefit, which led to a massive amount of hybrids in places like Los Angeles, came to an end recently, since they don't qualify for alternative-fueled vehicle incentives anymore, altough it's still valid for motorcycles. Considering the lesser space taken at the road surface by a motorcycle proportionally to the passengers capacity, they also make more sense in matter of traffic jam reductions.

No matter if it's a tiny Lambretta or a big Harley-Davidson, the size-to-occupation density is higher, so less space is taken at the road surface for each person transported by them instead of a Prius.

Even an old-school motorcycle with a simple carburettor-fed engine can still get better mileage than a hybrid car, altough nowadays the electronic fuel injection becomes prevalent.

Another aspect to consider is the amount of raw materials involved in the manufacturing of the whole vehicle, replacement parts (i.e. tyres, lamps, spark plugs, coils and cables, shock absorbers, friction material for clutch and brakes, among others) and other products needed to keep the vehicle operating properly, such as lube oils and greases, no matter if the car is a subcompact such as the Chevrolet Spark or if the fuel consumption is not so much more advantageous for the motorcycle, it's still usually more efficient from the factory to the end-of-life disposal.

A specific application where motorcycles can show other advantages is recreational off-roading: dirt-bikes are usually even more compact and lighter than a road-legal one, which increases their maneuverability in tight spaces where a Jeep would be too big to pass safely.

The lower weight also copes to reducing the risk of getting stuck in a mud pit, and is also easier to recover if gets stuck. Environmentally-wise, apart from the lesser amount of fuel and lube oils, motorcycles generate a lower pressure over the soil, in spite of the smaller contact surface due to narrower tyres. Basically, assuming that the contact with the nature is an essential part of recreational off-roading, the only disadvantage of motorcycles in this application is the lesser capacity to carry passengers, tools and replacement parts (and also a grill, charcoal, some beef and beer for a tailgate party) comparing to a 4WD.

After all, motorcycles have been a good answer to the demand for fuel-efficiency and an overall low running cost.