Flywheel Kinetic Energy Recovery Vacuum Pumping
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Solution Overview
Problem
Kinetic energy recovery systems with flywheels in vacuum enclosures face inefficiencies due to high frictional losses at high rotational speeds, which are mitigated by evacuation but require energy for pumping, reducing the energy that can be recovered and returned to the vehicle.
Innovation Solution
A kinetic energy recovery system utilizing a scroll vacuum pumping arrangement with a second vacuum enclosure providing backing pressure, allowing for periodic evacuation to maintain reduced pressure, thereby reducing the energy required for pumping and minimizing frictional losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the flywheel is located in a vacuum enclosure to reduce frictional losses, then efficiency is improved, but energy is consumed by the vacuum pump
Solution Approach 1:
The vacuum pump operates periodically rather than continuously. The system includes a vacuum pump that evacuates the vacuum enclosure at specific intervals (e.g., when the flywheel speed drops below a threshold or at predetermined times), rather than running constantly. This periodic operation reduces the energy consumption of the vacuum pump while maintaining the vacuum environment needed to minimize frictional losses during critical phases of flywheel operation.
Solution Approach 2:
The system changes the pressure parameter dynamically based on operational conditions. A pressure sensor monitors the pressure inside the vacuum enclosure and provides feedback to control the vacuum pump operation. When pressure rises above a predetermined threshold, the pump activates to restore the vacuum; when pressure is adequate, the pump stops. This dynamic parameter adjustment optimizes the balance between maintaining low friction and minimizing pump energy consumption.
2Quantity of substance
If the flywheel rotates at high angular velocity to store sufficient energy, then energy storage capacity is improved, but frictional resistance increases
Solution Approach 1:
The flywheel operates in a vacuum enclosure that creates an inert environment free from air resistance. By evacuating the enclosure to maintain vacuum conditions, the system eliminates frictional resistance from air molecules that would otherwise act on the high-speed rotating flywheel. This allows the flywheel to rotate at high angular velocities (e.g., 100,000 rpm) needed for sufficient energy storage while minimizing energy losses to friction.
3Loss of energy
If a vacuum pump is used to evacuate the enclosure, then friction is reduced, but device complexity increases
Solution Approach 1:
The system incorporates sensors and control mechanisms that enable it to automatically monitor and maintain its own vacuum environment without external intervention. A pressure sensor detects pressure changes inside the vacuum enclosure and triggers the vacuum pump only when needed, allowing the system to self-regulate and maintain optimal operating conditions while minimizing the operational burden and complexity of the vacuum pumping arrangement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves efficient energy recovery and storage with reduced energy consumption by using a scroll vacuum pumping arrangement and a secondary vacuum enclosure to maintain a backing pressure, enhancing the overall efficiency of the kinetic energy recovery process.
Implementation Method 1
a scroll vacuum pumping arrangement having an inlet arranged to be in fluid communication with an outlet of the first vacuum enclosure for evacuating the first vacuum enclosure
Implementation Method 2
a second vacuum enclosure having an inlet in fluid communication with an exhaust of the scroll pumping arrangement and arranged to be maintained at a pressure less than atmosphere for reducing the pressure at the exhaust of the scroll pumping arrangement
Implementation Method 3
Energy is stored by increased rotational speed of the flywheel. The energy stored is proportional to the moment of inertia and the square of the angular velocity
Implementation Method 4
At these high velocities, frictional resistance between a flywheel and ambient air generates large heat losses which decrease the efficiency of the recovery system. Therefore, the flywheel is located in a vacuum enclosure which is evacuated by a vacuum pump to reduce friction between the flywheel and the surrounding air
Data Source
Figure 1~2
Figure 3~4
AI summary
An improved kinetic energy recovery and/or storage system for vehicles or other devices employing kinetic energy recovery systems comprising a flywheel supported for rotation in a first vacuum enclosure for receiving energy from and dissipating energy to one or more parts of a vehicle; a scroll vacuum pumping arrangement having an inlet arranged to be in fluid communication with an outlet of the first vacuum enclosure for evacuating the first vacuum enclosure; a second vacuum enclosure having an inlet in fluid communication with an exhaust of the scroll pumping arrangement and arranged to be maintained at a pressure less than atmosphere for reducing the pressure at the exhaust of the scroll pumping arrangement, the second vacuum enclosure comprising an outlet through which gas can be pumped periodically for maintaining the second vacuum enclosure at a pressure less than atmosphere.