It’s no problem to shut down the diesel while waiting in line at the terminal and the temperature is moderate. It saves a bit of fuel and they say it’s good for Mother Nature.
However, you’re not as likely to shut down on a 38 C day.
Those high temperatures can hit you at seeding time, spraying, harvest or when hauling grain. And when it does, your factory installed air conditioner takes preference over pinching a few fuel pennies or saving a polar bear you’ve never seen.
The Polar Cab is designed to keep you cool on a scorching day when your diesel is turned off. If you’re on the combine with a full tank and it’s a while and a half before the grain cart will arrive, you can shut the engine down and keep the cab cool for as long as two hours. It’s the same deal in the sprayer waiting for the water truck or sitting in the seeding tractor waiting for the tender truck.
The Webasto Polar Cab is a self-contained AC unit. All it requires from the vehicle is a 24-volt plug to charge the internal battery that operates the entire stand-alone cooling plant.
It can be moved from vehicle to vehicle, wherever cool cab air is needed. Yes, that means you can bring it along in your camper so you can get some sleep in those suffering summer nights at the lake.
Polar Cab provides a cooling capacity of 7,000 BTU per hour without drawing on the implement’s engine or electrical system. The 24-volt variable speed compressor gets its energy from the vehicle’s charging system. The internal Webasto battery is charged every time the diesel is run.
The AC unit can be mounted on the cab roof or the cab floor.
The floor mount model would be easier to move than the roof model. Weight is approximately 92 pounds.
“The units are about the size of a loaf of bread, so either unit is easily installed. The Polar Cab is not integrated into the vehicle’s OEM AC system,” said Webasto spokesperson Rick Ashley, adding that the key is how to hold the cold.
“The system uses a unique thermal storage method. Inside the storage core is a series of aluminum micro-channels, which route liquid refrigerant around a graphite substrate that is infused with water. The water turns to ice.
“This substrate in the Polar Cab is highly efficient at storing cold. The ice remains in the frozen state for a very long time, up to eight hours. So you can turn off the diesel engine and the stored cold is transferred into the cab for cooling, allowing operators to leave their engine off and maintain cool cabin temperatures.”
Albrecht Otte, Wabasto’s engineer on the project, said the system depends on doing everything just right and keeping the size small.
“We have very efficient insulation,” Otte said.
“We keep the ice block frozen up to eight hours, even when it’s 110 F (43 C) outside and we leave the truck in the sun. In these eight hour trials, the ice block diminishes by only 10 percent of its capacity.”
He said that even if the truck sits in the sun at 43 C for 16 hours, it still has enough ice capacity to cool the cab for half an hour.
“One set of aluminum micro channels carries a very cold glycol/water refrigerant mix through the core. The core is a graphite foam matrix. It contains straight water, like a sponge. We use graphite foam because if we made our ice block in a solid container, it would rupture when it expands from freezing. Holding the water in this foam prevents it from bursting the container.
“The second set of aluminum micro channels carries cold glycol/water refrigerant from the frozen ice block out to the heat exchanger in the cab. It has a temperature just above freezing. The fan circulates this cold air.”
Arctic Start is another new system from Webasto. Heating systems for starting diesels in cold weather have been around for decades. They pre-heat engines and the cab and warm the fluids.
Webasto said its new Arctic Start Thermo Pro 50 is more compact and lighter in weight with high altitude capabilities at 7,200 feet. It’s designed to provide quick engine pre-heat even in extremely cold conditions with 17,000 BTU per hour heating power.
The larger Thermo Pro 90 also has the Arctic Start feature with automatic altitude adjustment up to 11,000 feet and 31,000 BTU per hour of heating power.
The Polar Cab and Arctic Start units can be bought as aftermarket items or ordered as OEM from some manufacturers.