ORC Expansion Machine Injection Control
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Solution Overview
Problem
The integration of Organic Rankine Cycle (ORC) systems with external processes lacks rotational speed control, leading to inefficiencies and potential system damage due to fixed volume ratios and uncontrolled pressure levels, which results in reduced cost-effectiveness and increased risk of exceeding maximum permissible temperatures and pressures.
Innovation Solution
The introduction of a first and second supply apparatus with actuatable throttle elements allows for dynamic control of the expansion ratio and temperature, enabling the injection of preheated working medium into the expansion machine, and a controllable recirculation apparatus to stabilize mass flows, coupled with an optional external drive train for rotational control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the expansion machine is directly coupled to external processes without a transmission, then compactness and cost are improved, but rotational speed control is lost
Solution Approach 1:
The system uses the external process itself to drive the feed pump, eliminating the need for separate motor drives and transmissions. The expansion machine directly couples to the external process, and the feed pump is driven by the same external process, creating a self-sufficient system without additional transmission components.
2Ease of manufacture
If the expansion machine is directly coupled to external processes without a transmission, then cost is improved, but rotational speed control is lost
Solution Approach 1:
The external process provides the driving force for both the expansion machine and feed pump, eliminating the need for separate motors and transmissions. This self-service arrangement reduces component count, manufacturing complexity, and overall system cost while maintaining operational capability.
3Productivity
If superheating is increased, then efficiency is improved, but component temperature limits are exceeded
Solution Approach 1:
The system applies partial superheating rather than excessive superheating. The superheater provides just enough superheat to improve expansion efficiency while keeping the temperature within the maximum permissible limits of the expansion machine components, avoiding the harmful effects of overheating.
4Adaptability or versatility
If a variable volume ratio is implemented by variable inlet or outlet window, then expansion control is improved, but device complexity and cost increase
Solution Approach 1:
The system controls expansion by changing the mass flow rate parameter rather than modifying the physical geometry of the expansion machine. By adjusting the mass flow of the working medium through the feed pump and supply apparatus, the system achieves variable expansion effects without complex mechanical modifications to the expansion machine structure.
5Power
If mass flow is increased, then power output is improved, but evaporation completeness is reduced
Solution Approach 1:
The system dynamically adjusts the mass flow rate based on evaporation conditions. The feed pump and supply apparatus can vary the mass flow of preheated working medium to match the evaporation capacity of the evaporator, ensuring complete evaporation while optimizing power output. This dynamic control prevents liquid carryover into the expansion machine.
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 solution reduces superheating, adapts the expansion ratio dynamically, prevents excessive pressures, and stabilizes mass flows, enhancing efficiency and safety while maintaining compactness and cost-effectiveness by allowing rapid control of live steam temperature and volume ratios.
Implementation Method 1
a preheater (10) for preheating a working medium
Implementation Method 2
an evaporator (20) for evaporating and possibly superheating a first mass flow of the preheated working medium
Implementation Method 3
an expansion machine (30) for expanding the evaporated and superheated first mass flow of the working medium
Implementation Method 4
a condenser (60) for condensing and optionally subcooling the working medium exiting at the outlet
Data Source
AI summary
The invention relates to a thermodynamic cycle device, in particular an ORC device, comprising a preheater for preheating a working medium; an evaporator for evaporating and superheating a first mass flow of the preheated working medium; an expansion machine for expanding the evaporated and superheated first mass flow of the working medium; a condenser for condensing the working medium exiting the expansion machine; a feed pump for pumping condensed working medium to the preheater; and a first supply apparatus for supplying a second mass flow of the preheated working medium to the partially expanded first mass flow of the working medium in the expansion machine. The invention further relates to a corresponding method.