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Capstone Turbine working with Kenworth and Peterbilt on heavy-duty microturbine range-extended trucks

Capstone Turbine Corporation is working with domestic heavy duty truck manufacturers Kenworth and Peterbilt to demonstrate Class 7 and Class 8 microturbine range extended series hybrid trucks.

During the recent Hybrid Truck User’s Forum in Baltimore Maryland, it was announced that both Kenworth and Peterbilt are working with Capstone to demonstrate Class 7 and Class 8 microturbine range extended series hybrid trucks using Capstone’s CARB certified C65 microturbines. Both vehicles are concept trucks intended to quantify the performance, efficiency, and economic benefits of a microturbine-based series hybrid solution.

The Kenworth truck is operational and is currently running on the company’s test track in Washington state, and the Peterbilt truck is being assembled.

Comments

HarveyD

Will micro turbine go the 1,000,000 miles as current diesels do? Since weight is not so critical on heavy trucks, high efficiency diesel gensets could do a longer lasting job?

Nick Lyons

Surely these would not make sense for long-haul applications, where LNG makes a lot more sense as a replacement for diesel. They must be targeting in-city, short haul duty cycles. I like micro-turbines as range extenders (clean burning, light weight). Cost is an issue, which is perhaps why they are looking at commercial vehicles.

Nick Lyons

Surely these would not make sense for long-haul applications, where LNG makes a lot more sense as a replacement for diesel. They must be targeting in-city, short haul duty cycles. I like micro-turbines as range extenders (clean burning, light weight). Cost is an issue, which is perhaps why they are looking at commercial vehicles.

David Freeman

@Nick - this is perfect for long-haul applications. As long as the AVERAGE power consumption <65kW, the turbine will charge the batteries for acceleration and mountain-climbing. Capstone can use either diesel or NG, so it's just a matter of changing the fuel system. What you need to compare is the capital cost of the turbine+batteries plus lifetime fuel costs to the capital cost of a diesel/NG engine plus lifetime fuel costs.

@HarveyD - Capstone turbines are rated for 45000 hours life. Assuming no idling (battery is used for that) and average speed of 60m/h, expected lifetime is 2.7 million miles. Granted, that's 45000 hours in CHP applications (stable, environmentally isolated environment), so that could come down a bit. Still, I'd say it's likely they'll reach a million miles lifetime.

Henry Gibson

For over ten years, I have been following the progress of the Capstone micro-turbines. The 30 kW units were the first. Then the 60 Kw units came next followed by the 65 kW units. Now 200 kW units are available. All units have self actuated air bearings, so no lubricating oil is needed. None of the units use liquid cooling or radiators, so no coolant fluid is needed. The smaller sizes can be fitted with equipment so that the exhaust is more free of smog producing chemicals than the intake air, so little or no exhaust treatment is needed.

It is intended that diesel fuel be able to be burned in many such Capstone turbine vehicles as it has been burned for about ten years in Capstone powered buses, and there is no reason that a mix of fuel could not be used. Burners could be built that could burn either gasoline or diesel or biodiesel or pure vegetable oil or ethanol or methanol or a mix without any physical changes because there is no octane or cetane requirement for the fuel. Liquid propane or butane combustion may also be used in such vehicles with the proper tanks.

Liquid natural gas requires special vacuum insulated Dewar flasks, but it is now possible for any refueling stop that has a connection to a natural gas pipeline to liquify its own natural gas fuel just as it was possible for them to provide compressed natural gas fuel.

Capstone turbines have only one moving part in contrast to the hundreds of parts in engines, and there is no air bearing wear at all during operation and little wear only during turbine stops and starts, so even several stops during a day do not result in much wear. Air filters need to be changed every 8000 hours in stationary operation and perhaps more often in on road operation, but 8000 hours is 400,000 miles at fifty miles per hour.

For not entirely unimaginable reasons, the Capstone turbines are much more expensive than diesel engines with many more parts, but diesel engines have been being made for about 100 years. The maintenance costs of the diesels usually make the turbines cost less in the long run.

ZEBRA batteries were used in some of the Capstone energized buses, and they or the equivalent GE Durathon units should be used in these hybrid tractors. The large batteries will provide the air-conditioning and heating loads during the required rest stops so no idling losses exist. The hottest possible outside air can be used to cool these batteries as they are used to store and deliver new and regenerated energy. The battery heat can also be used for cab and cargo heating.

Stationary Capstone turbines are frequently fitted with exhaust heat recovery for co-generation of heat or organic Rankine turbo-generators for more electrical output, and Capstone will eventually have such units available for moving vehicles. They could even have a welded hermetic version with their gas bearing technology that has a life of over ten years.

Professor Roger Waller of DLM could even design a steam engine for the trailers that would use the turbine exhaust heat in a boiler to provide steam to the trailer wheel steam engine or just a small steam turbine. Livio Dante Porta's boiler water treatment would allow the boiler to be kept clean and useful for over ten years with the worst water available at refueling stations.

..HG..

Roger Pham

I'm wondering about the economics of the whole thing: How can the Capstone micro turbine at 30% peak thermal efficiency competes with big turbodiesel at 45% peak thermal efficiency? Or there has been a major improvement in microturbine efficiency?
Is the foil bearing spinning at ~100,000rpm capable of withstanding the repeated road shocks of an 18-wheeler truck? Stationary application and aircraft are not subjected to the same degree of shocks.
Is 65 kW sufficient for an 80,000-lb vehicle? Is this number flat-rated like in aircraft, whereby it can maintain the same 65 kW power even on a very hot day at 7,000-ft altitude?

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