Solution’s Advantages and Impact
Efficiency. A kinematics analysis of our Phase I EMCP design demonstrates that 17W of power is required to manipulate the pitch of a 21” fan’s blades generating 20,000 cfm (presenting a power draw of 21kW for spin control). As compared to a hydraulically-controlled pitch fan from Flexxaire (primarily targeted at agricultural applications), our pitch-actuation mechanism draws 1/12th the power of Flexxaire’s solution which was measured in a bench test to require a nominal 200W power draw (with excursions as high as 720W) for pitch control alone. EMCP will not need frequent injection of energy to maintain blade pitch at a fixed position as may be required for hydraulic pitch actuation (depending on the state of repair of the oil distribution box).
Having considered the efficiency of the pitch actuation, the overall efficiencies of varied pitch then depend on how aggressively the fan/propeller’s speed is changed. For instance, Sukup, a manufacturer of manually adjusted agricultural fans, found that every 2˚ change in blade pitch would result in approximately an 8-10 amp drop in current draw. Also, consider Allan Bradley’s (ABB) case study of augmenting fixed-speed fans with variable speed drives (VSD) without the benefits of pitch control. In this stuck-in-first-gear-like scenario, ABB found that changing a UK power plant’s 200 kW fan to variable speed operation resulted in a yearly energy savings of 1,000,000 kWh with a payback period on up-front investment of 16 months; a similar change to a Finish pulp mill’s 1,370kW fan generated savings of nearly 376,000 kWh/year with better pressure control; changing an industrial power plant’s inlet guides vanes to VSD for its forced-draft fan resulted in energy savings of 482,000 kWh/year with better pressure control from varying loads, reduced maintenance from soft start and more efficient combustion; Abbot Power uses of VSDs resulted in energy savings of $63,000 per year and reduced maintenance and hardware costs of $10,000 per year with a payback period of 24 months. ABB stated a general expected reduction in power draw, from speed control alone, of a factor of 1/8.
The magnitude of these savings begs the question, what could pitch control possibly add? Similarly, for applications already “benefiting” from hydraulic pitch control, why would one switch to EMCP? Wärtisilä provides a powerful suggestive answer in a case study for the Motor Vessel Henricke. Wärtisilä replaced an existing aged analogue control system “which controls a combination of propeller pitch deflection” and shaft speed along with new blades to replace 1-year old blades that had experienced heavy cavitation from the prop’s inefficient operation. The new hardware and a more sophisticated control system enabled the MV Henricke to save 800 liters of fuel in a 24-hour sailing period which can aggregate to approximately 170,000 liters of fuel per annum assuming 210 days per year of sailing. If such savings can be experienced by upgrading old hydraulics with new technology still dependent on hydraulics, the potential for EMCP becomes much more promising.
Our own power-draw analysis, as well as that of ABB, does not necessarily consider overall system efficiency. We consider the effect of fan power draw alone and have not as yet generated technical analysis on the overall impact of maintaining continuous air flow on engine and electronic systems efficiency. When analyzed through simulation, this work is sophisticated and labor intense – while onboard system measurement seems more appropriate for Phase II/III.
Cool Mechatronics is submitting a “Commercial Solutions Offering” under the “Artificial Intelligence in Power Management Systems” in which we plan to develop a digital twin of a military fighting vehicle’s coolant sources and sinks to be combined with algorithms that adapt to the vehicle’s in-situ operating duty in the context of ambient temperature permitting use of adaptive control algorithms which will help keep cooling optimal and efficient. Anticipations of cooling demands will optimize EMCP’s power saving potential by running the fan at the lowest speed possible with optimized pitch – instead of maximum fan operation given an after-the-fact thermal event (colloquially, “fool-in-the-shower reactivity).