ConstructionWorX DIGITAL
Flywheel Energy Storage and H2-ICE for Off-Highway Machinery PUNCH Flybrid, a leading producer of mobile flywheel energy storage solutions, looks at innovations in energy storage systems. PUNCH Flybrid has launched production of its 600 Series Energy Storage system, for use with a range of off-highway construction machinery ranging from excavators to dynamically operated diesel and gas generators. The high-power density and durability of a flywheel energy storage system makes it ideally suited to the duty cycles and usage patterns typically observed on such machines. Long operational hours, with frequent high-power events, pose degradation and thermal challenges for other energy storage solutions such as batteries and super-capacitors. The flywheel captures energy that would normally be wasted when a machine decelerates to a stop or when, for example, the boom on an excavator is lowered, and deploys this energy on the next working cycle. This can be used to assist the prime power unit of the vehicle to either reduce its fuel consumption or increase its productivity.
Flywheel Technology At the heart of the 600 series system, is a patented flywheel design capable of over 80,000hrs of operation, with no degradation in performance. A key feature of PUNCH Flybrid’s flywheel technology is its vacuum seal design which allows the flywheel to run in a vacuum for maximum efficiency, while simultaneously allowing for a shaft type power take-off. This means that the flywheel can be integrated into a machine in different ways, electrically when coupled to an electric motor, mechanically via a transmission or hydraulically when connected to a hydrostatic pump. The flywheel module is constructed from materials and techniques widely adopted in the automotive industry making it efficient to produce, is ultra-reliable and also gives the flywheel a low embedded CO2 figure allowing the machine to achieve even greater CO2 savings.
18 JUNE 2021
H2-ICE for heavy duty vehicles While the passenger car market is moving rapidly towards increased levels of vehicle electrification as a means of reducing CO2 emissions, the requirement of heavy and expensive batteries makes this inefficient for heavy vehicles with large energy requirements such as those in the construction industry. For these types of vehicles, hydrogen offers a more sustainable and cost-effective decarbonisation route. Recent years have seen renewed interest in H2-fuelled ICEs as alternatives to fuel cells. Fuel cells tend to have a higher peak efficiency at low loads but the efficiency rapidly deteriorates in the mid to high load regime. The efficiency of an ICE, on the other hand, peaks and plateaus at the mid to higher loads. As a result, for machines predominantly operated at high loads, the efficiency of an H2 ICE is in fact comparable to that of a fuel cell. Moreover, extensive work by PUNCH Torino who are currently in the advanced stages of developing a H2-fuelled ICE, shows that for hybridised machines the engine operation can be more easily constrained to the optimal region. When combined with their lower initial purchase cost, this places H2-fuelled ICEs very favourably in terms of Total Cost of Ownership (TCO). Additionally, H2-fuelled ICEs can leverage an already existing production infrastructure, servicing network and skilled workforce.
