Volumetric Expander with Regulated Valve for Rankine Cycle
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Solution Overview
Problem
Existing Rankine cycle systems are inefficient for harnessing medium/low temperature thermal sources due to high costs, maintenance requirements, and sensitivity to fluid flow and rotation speed variations, making them unsuitable for small-scale applications with variable thermal supplies.
Innovation Solution
A closed Rankine cycle plant incorporating a volumetric expander with a rotative valve and regulation device, which allows for efficient conversion of thermal power to electric power with reduced complexity and maintenance needs, using a working fluid that can operate effectively across a range of conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam turbines are used for heat recovery, then power generation efficiency is improved, but device complexity and maintenance requirements increase significantly
Solution Approach 1:
The patent replaces expensive, complex steam turbines with simpler, more robust expanders that have fewer moving parts and lower maintenance requirements. These expanders are designed to be more durable and less sensitive to operational variations, effectively substituting high-maintenance equipment with lower-maintenance alternatives while maintaining acceptable efficiency levels for small-scale applications.
Solution Approach 2:
The patent substitutes traditional mechanical steam turbine systems with alternative expander mechanisms that operate on different mechanical principles. These expanders use simpler mechanical designs with reduced component counts, eliminating the need for complex control systems and frequent maintenance while still achieving effective power generation from low-to-medium temperature heat sources.
2Power
If steam turbines are used for heat recovery, then power generation capability is improved, but sensitivity to flow rate and rotation speed variations worsens
Solution Approach 1:
The patent employs expanders with dynamic operational characteristics that allow them to adapt to varying flow rates and thermal inputs. The expander design incorporates adjustable parameters and flexible operating ranges that enable the system to maintain stable performance despite fluctuations in heat supply, unlike rigid steam turbines that require precise operating conditions.
Solution Approach 2:
The patent utilizes expanders whose performance characteristics can be adjusted through parameter changes such as clearance volumes, compression ratios, and operating pressures. This allows the system to optimize performance across a range of thermal inputs and flow rates, providing versatility for small-scale and variable heat recovery applications without the sensitivity issues inherent in steam turbine systems.
3Productivity
If steam turbines are used for heat recovery, then efficiency at optimal conditions is improved, but cost increases significantly
Solution Approach 1:
The patent replaces costly steam turbine equipment with more affordable expander systems that are cheaper to manufacture, install, and maintain. These alternative expanders use simpler construction methods and fewer expensive components, making heat recovery economically viable for small-scale and distributed applications where steam turbines would be prohibitively expensive.
4Power
If steam turbines are used for heat recovery, then power generation capability is improved, but maintenance frequency increases
Solution Approach 1:
The patent substitutes steam turbines with expander systems that have inherently higher reliability and lower maintenance needs. These expanders are designed with fewer wear-prone parts, simpler sealing requirements, and greater tolerance to operational variations, resulting in reduced maintenance frequency and improved overall system reliability for continuous power generation operations.
Data Source
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AI summary
Closed cycle plant (1), particularly a Rankine cycle plant, for converting thermal power into mechanical and/or electric power, comprising: a closed circuit (2) inside which a working fluid circulates according to a predetermined circulation direction, a volumetric expander (4) configured to receive at the inlet the working fluid at the gaseous state. The volumetric expander (4) comprises: a jacket (5) having an inlet (8) and an outlet (9) respectively suitable for enabling to introduce and discharge the working fluid, an active element (6) housed in said jacket and suitable for defining, in cooperation with said jacket (5), a variable volume expansion chamber (7), a main shaft (11) associated to the active element (6) and configured to rotatively move around an axis, a valve (10) active on the inlet and outlet of the jacket (5), and configured to selectively open and close the inlet and outlet to enable at least one condition of introducing, one condition of expanding and one condition of discharging the working fluid from said expansion chamber (7), an electric or mechanical power generator (12) connected to the main shaft (11). The valve (10) comprises an regulation device (14) configured to enable to vary at least one of the following parameters: the duration of the introduction condition, the maximum through cross- section of the inlet (8).