Thermal Extraction System Using Pulsating Supercritical Fluid
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Solution Overview
Problem
Conventional methods are inefficient in converting low-grade thermal energy, ranging from 34° F. to 210° F., into useful products like electricity or mechanical work, as it is too low for conventional Rankine cycles to utilize effectively.
Innovation Solution
A process utilizing a liquid or supercritical working fluid, such as R134a or CO2, in a thermal circuit where the fluid is compressed, heated within a heat exchanger, and then expanded through an expander to generate work, without complete phase change, allowing for the extraction of thermal energy from sources like waste heat, geothermal, and natural water bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional Rankine cycle or vapor cycles are used to generate useful energy from thermal sources, then the system can operate at higher temperatures, but it cannot effectively utilize low-grade thermal energy in the range of 34°F to 210°F
Solution Approach 1:
The invention changes the working fluid parameters by using organic fluids, refrigerants, or CO2 that can operate effectively at low temperatures (34°F to 210°F). The fluid is compressed to high pressure while remaining liquid, then heated at constant volume to generate high pressure that drives the expander, enabling productive energy generation from low-grade thermal sources that conventional cycles cannot utilize.
2Use of energy by moving object
If complete phase change to vapor is achieved in the heat exchanger, then more thermal energy can be extracted, but the system complexity and control difficulty increase significantly
Solution Approach 1:
The invention applies partial phase change rather than complete vaporization. The working fluid is heated at constant volume in the heat exchanger, causing partial phase change (about 5% to 50% or less expansion) that generates sufficient pressure for expander operation without requiring complete vaporization. This reduces control complexity while maintaining effective energy conversion.
3Stress or pressure
If the working fluid is heated at constant pressure in a conventional heat exchanger, then heat transfer is simplified, but the pressure increase is insufficient to drive the expander effectively
Solution Approach 1:
The working fluid is pre-compressed to high pressure while in liquid state before entering the heat exchanger. This preliminary compression enables the fluid to absorb thermal energy at constant volume and generate even higher pressure through thermal expansion, creating sufficient pressure differential to drive the expander effectively without requiring complex high-pressure heat exchanger designs.
4Loss of energy
If low-grade thermal energy from waste heat sources is utilized, then energy waste is reduced, but the available temperature range is too low for conventional energy conversion systems
Solution Approach 1:
The invention converts waste heat from low-grade thermal sources (34°F to 210°F) into useful mechanical work and electricity. By using organic working fluids that can operate at these low temperatures and implementing constant volume heating with subsequent expansion, the system transforms previously unusable waste heat into beneficial energy output, reducing energy loss while accommodating the limited temperature range.
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 method effectively converts low-grade thermal energy into useful work or electricity with improved efficiency, utilizing a pulsating flow to maximize power output and thermal efficiency, even from sources that conventional systems cannot utilize.
Implementation Method 1
Heat from a thermal source, for example as collection fluid in the form of exhaust gases from combustion, or as a collection liquid heated from the thermal source, is flowed through the other side of the heat exchanger such that a transfer of thermal energy from the collection fluid or collection liquid into the working fluid takes places
Implementation Method 2
The outlet valve on the heat exchanger is then opened allowing the heated and high pressure working fluid to enter one or more expanders (for example, piston or rotary) where expansion is allowed to take place. As the working fluid expands in the expander, useful work is extracted to an output shaft
Data Source
AI summary
A process and system of extracting useful work or electricity from a thermal source, wherein heat energy from the thermal source is used in the form of a heated collection fluid; a first side of a heat exchanger is filled with a liquid or supercritical working fluid; fluid flow out of the first side of the heat exchanger is closed such that a fixed volume of the working fluid is maintained in the first side; the heated collection fluid flowed through a second side of the heat exchanger that is adjacent to the first side to affect a transfer of heat from the heated collection fluid to the fixed volume of the working fluid to raise its temperature and pressure; the pressurized working fluid is released from the first side of the heat exchanger upon the working fluid reaching a threshold state; a flow of the pressurized working fluid is directed to an expander capable of converting the kinetic energy of the pressurized working fluid into useful work or electricity; and the foregoing steps are repeated. A plurality of such operably coupled heat exchangers may be used in a manner such that the timing of the pressurized working fluid from each heat exchanger to the expander is offset.