Turboexpander Mechanical Coupling for ORC Waste Heat Recovery
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Solution Overview
Problem
Current combined systems for mechanical drive applications using Organic Rankine Cycles (ORCs) are complex and inefficient due to the need for multiple electric machines and variable frequency drivers, which negatively impact overall conversion efficiency and increase costs.
Innovation Solution
A power converting system incorporating a turboexpander with a variable-speed mechanical coupling to a rotating load, utilizing waste heat from a gas turbine system, and featuring a variable inlet guide vane system for controlling flow rate and pressure, allowing for efficient start-up and speed control of the rotating load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple electric machines and variable frequency drivers are used in the combined system, then the rotating load can be controlled at variable speeds, but the overall conversion efficiency decreases and system complexity increases
Solution Approach 1:
The patent extracts and eliminates the electric machines and variable frequency drivers from the combined system. By directly mechanically coupling the turboexpander to the rotating load, the system removes the intermediate conversion steps (mechanical-to-electrical-to-mechanical), thereby reducing complexity while maintaining variable speed control through direct mechanical means
Solution Approach 2:
The patent replaces the electrical control system (electric machines and variable frequency drivers) with a direct mechanical coupling system. The turboexpander is mechanically connected to the rotating load, allowing direct transmission of mechanical power and enabling speed control through mechanical means rather than electrical conversion
2Adaptability or versatility
If multiple electric machines are used for power conversion, then flexible power transmission is achieved, but the overall conversion efficiency decreases due to multiple conversion steps
Solution Approach 1:
The patent extracts the intermediate electric conversion components from the power transmission path. By eliminating the electric machines, the system removes the inefficient mechanical-to-electrical-to-mechanical conversion steps, achieving direct mechanical power transmission from the turboexpander to the rotating load, thereby reducing energy losses
Solution Approach 2:
The patent establishes continuous mechanical power transmission from the turboexpander directly to the rotating load. This eliminates the discontinuous conversion cycles inherent in electric machine systems, maintaining continuous useful mechanical action and minimizing energy losses during power transmission
3Ease of operation
If electric machines and variable frequency drivers are incorporated, then precise speed control is achieved, but system costs increase
Solution Approach 1:
The patent extracts and removes the expensive electric machines and variable frequency drivers from the system. By using direct mechanical coupling, the system achieves speed control through simpler, more cost-effective mechanical means, thereby reducing overall system costs while maintaining operational control
Solution Approach 2:
The patent replaces expensive, complex electric control components with simpler, more economical mechanical coupling elements. The direct mechanical connection uses less costly components that can be manufactured more easily, reducing the overall system cost while achieving the necessary speed control functionality
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
This configuration simplifies the system, enhances efficiency by directly coupling mechanical power from the turboexpander to the rotating load, and reduces complexity and costs by eliminating the need for multiple electric machines and variable frequency drivers.
Implementation Method 1
A source of waste heat and an Organic Rankine Cycle (ORC) system, comprised of at least a turboexpander... Hot, pressurized working fluid expands in the turboexpander and mechanical power is generated thereby
Implementation Method 2
featuring a variable inlet guide vane system for controlling flow rate and pressure
Implementation Method 3
a variable-speed mechanical coupling between the turboexpander and the rotating load... The mechanical power is used to drive an output shaft of the turboexpander. The turboexpander output shaft is mechanically coupled via the variable-speed mechanical coupling to the driven shaft of the rotating load
Data Source
AI summary
A power converting system is described, comprising a source of waste heat and an organic Rankine cycle system. The organic Rankine cycle system in turn comprises at least a turboexpander, at least a rotating load mechanically coupled to the turboexpander and driven thereby, and a variable-speed mechanical coupling between the turboexpander and the rotating load.