Channel Flow Boiler Heat to Mechanical Energy Conversion
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Solution Overview
Problem
Conventional Rankine cycle engines have low exergetic efficiencies, especially at low temperatures, due to significant energy losses in pumping the working fluid and inherent losses associated with pool boiling processes, limiting their ability to effectively convert low-grade heat into mechanical energy.
Innovation Solution
A device and method that utilize a channel flow boiler to generate a liquid-gas mixture, which is then expanded in an expansion device, with the option to supply heat to the mixture, allowing for approximately isothermal expansion and conversion of internal and kinetic energy into mechanical energy, reducing energy losses and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a classical Rankine cycle is used with discrete components (boiler, expander, condenser, pump), then the system can convert heat into mechanical energy, but significant energy losses occur due to pumping work and pool boiling inefficiencies
Solution Approach 1:
The patent merges the boiler and expander into a single integrated device where the working fluid is heated in channels and directly expands to drive a movable element. This eliminates the need for separate discrete components and reduces energy losses by maintaining continuous flow and eliminating the pumping step required in classical Rankine cycles.
Solution Approach 2:
The patent extracts the pump component from the classical Rankine cycle by utilizing the natural expansion and phase change of the working fluid within the integrated device. The working fluid is heated and expands directly to drive the movable element without requiring external pumping, thereby eliminating the energy losses associated with pumping work.
2Loss of energy
If steam entry temperatures are limited by material properties (565°C), then the equipment can operate reliably, but the theoretical Carnot efficiency (63%) is not achieved due to actual efficiency limitations (42%)
Solution Approach 1:
The patent changes the operating parameters by using an integrated channel flow design that allows for more efficient heat transfer and expansion. The working fluid is heated directly in channels and expands to drive the movable element, achieving higher exergetic efficiency by minimizing temperature gradients and heat losses compared to conventional steam engines operating at 565°C.
3Volume of stationary object
If organic working fluids are used in ORC engines at lower pressures and temperatures, then device size ratios can be maintained, but exergetic efficiencies remain low compared to the Carnot limit
Solution Approach 1:
The patent merges the heating and expansion processes into a single integrated device with internal channels. The working fluid is heated within the device's channels and directly expands to drive the movable element, eliminating the need for separate external components. This integration maintains compact device size while significantly improving exergetic efficiency by minimizing heat losses and maintaining continuous flow.
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 approach enhances the conversion of heat into mechanical energy by minimizing energy losses and maintaining kinetic energy, achieving higher efficiencies compared to traditional Rankine cycle engines, particularly at lower temperatures.
Implementation Method 1
a channel flow boiler having at least one channel adapted to heat a working fluid for generating a liquid-gas mixture
Implementation Method 2
an expansion device adapted to expand the liquid-gas mixture... the method is operated as a thermodynamic cycle such that the expansion of the liquid-gas mixture is approximately isothermal
Data Source
AI summary
A device for converting heat into mechanical energy is disclosed. The device includes a channel flow boiler having at least one channel adapted to heat a working fluid for generating a liquid-gas mixture; an expansion device adapted to expand the liquid-gas mixture; and a movable element arranged such that the expanding liquid-gas mixture at least partially converts an internal and/or kinetic energy of the liquid-gas mixture into mechanical energy associated with the movable element; wherein the channel flow boiler and/or the expansion device is adapted to supply heat to the liquid-gas mixture.