Cascaded ORC Plant with Partializable Turbines for Variable Thermal Loads
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Solution Overview
Problem
Current Organic Rankine Cycle (ORC) systems are limited by thermal power availability, temperature levels, and variability in thermal load, making them inflexible and inefficient in adapting to different operating conditions, with low electrical power output due to high molecular weight fluids and limited flowrates.
Innovation Solution
A cascaded ORC system with partializable turbines and multiple organic fluids operating at different pressure and temperature levels, where each fluid's condensation causes evaporation of the next, maximizing energy recovery and maintaining constant turbine revolutions per minute through hydraulic devices, and incorporating heat-accumulation and energy-integration means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high molecular weight organic fluids are used in ORC systems, then the thermal efficiency is improved, but the electrical power output is reduced due to limited flowrates
Solution Approach 1:
The system divides the ORC cycle into multiple cascaded stages, each using a different organic fluid optimized for its specific temperature and pressure range. This segmentation allows each stage to operate at optimal conditions, recovering heat more completely while maintaining acceptable flowrates for electrical power generation.
Solution Approach 2:
The invention changes the operating parameters (temperature, pressure, fluid type) for each cascaded stage to match the heat source characteristics. By adjusting these parameters across stages, the system maximizes both thermal efficiency and electrical power output rather than being constrained by a single fluid's limitations.
2Loss of energy
If ORC systems are designed for specific operating conditions, then the thermal efficiency is optimized, but the adaptability to different operating conditions is reduced
Solution Approach 1:
The cascaded ORC system design provides multi-functionality by accommodating various heat source temperatures and flow rates through its multiple stages. Each stage can be configured to handle different operating conditions, making the overall system universally applicable to diverse industrial waste heat sources without requiring complete redesign.
Solution Approach 2:
The system incorporates dynamic control mechanisms that allow adjustment of fluid flow distribution across stages based on actual operating conditions. This dynamic capability enables the system to adapt to varying thermal loads and heat source characteristics while maintaining optimal efficiency at each stage.
3Adaptability or versatility
If the thermal load is variable in time, then the flexibility is improved, but the stability of thermal power availability is reduced
Solution Approach 1:
The cascaded system structure ensures continuous heat recovery by routing the exhaust from one stage directly to the next stage's evaporator. This continuous action eliminates idle time between stages and maintains stable thermal power availability even when the overall thermal load varies, as each stage operates continuously within its optimized parameter range.
Data Source
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AI summary
A plant for the production of energy that is based upon the organic Rankine cycle (ORC). The plant comprises a first ORC system, comprising a first organic operating fluid circulating, in sequence, between a first evaporator in conditions of heat exchange with a heat source, a first expansion stage in a turbine operatively connected to a generator, a first evaporator/condenser, and a first pump for recirculating said first organic operating fluid to said first evaporator. Said turbine is a partializable turbine and comprises means for partializing the incoming flowrate of said organic operating fluids, said means being designed to partialize said incoming flowrate to keep the r.p.m. of said turbine constant.