Heat Exchanger Fan Speed Control for Compressor Inlet Pressure
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Solution Overview
Problem
Existing heat engine systems face challenges in controlling the pressure of the working fluid at the inlet of the main compressor, which affects efficiency and requires large storage tanks and high-flowrate pumps, increasing complexity and costs.
Innovation Solution
A heat engine system with a control system and heat exchanger assembly that modulates the rotational speed of fans to adjust the pressure of the working fluid, using a heat exchanger assembly with gas-cooled heat exchangers and fans to direct a cooling medium, thereby controlling the thermodynamic quality and density of the working fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump and storage tank are used to control working fluid pressure at the compressor inlet, then pressure control is achieved, but system footprint and device complexity increase due to large storage tanks and high-flowrate pumps
Solution Approach 1:
The invention extracts and eliminates the storage tank from the system by using the condenser to directly control working fluid pressure through condensation. The condenser serves dual functions: heat rejection and pressure control, removing the need for separate storage infrastructure.
Solution Approach 2:
The condenser is designed to perform multiple functions simultaneously: it acts as both a heat rejection device and a pressure control mechanism. By controlling the condensation rate through cooling medium flow rate adjustments, the system uses a single component for both thermal management and pressure regulation.
2Reliability
If a high-flowrate pump is used to control working fluid pressure, then pressure control is achieved, but startup time and operating costs increase
Solution Approach 1:
The invention replaces the mechanical pump-based pressure control system with a thermal-based control mechanism. Instead of using mechanical energy to force fluid flow and control pressure, the system uses thermal condensation processes regulated by cooling medium flow rate to achieve pressure control.
Solution Approach 2:
The system uses the working fluid's own condensation process to control its pressure. The condensing working fluid naturally regulates pressure at the compressor inlet without requiring external pumping action, allowing the system to be self-regulating.
3Reliability
If a high-flowrate pump is used to control working fluid pressure, then pressure control is achieved, but operating and maintenance costs increase
Solution Approach 1:
The invention removes the high-flowrate pump from the system architecture, eliminating the capital cost of purchasing and installing such equipment as well as the ongoing operating and maintenance costs associated with high-power pumping systems.
Solution Approach 2:
The system uses low-cost cooling medium circulation instead of expensive high-flowrate pumping. The cooling fans and heat exchanger represent a more economical approach compared to high-power pump systems, reducing both capital expenditure and operational costs.
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 reduces the system footprint, enhances efficiency in transforming thermal energy to mechanical and electrical energy, and simplifies startup processes by eliminating the need for large storage tanks and high-flowrate pumps.
Implementation Method 1
The heat exchanger assembly may include a plurality of gas-cooled heat exchangers configured to transfer thermal energy from the working fluid to a cooling medium
Implementation Method 2
The plurality of fans may be configured to direct the cooling medium into contact with the plurality of gas-cooled heat exchangers
Data Source
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AI summary
Systems and methods are provided for controlling the pressure of a working fluid at an inlet of a main pressurization device of a heat engine system. The heat engine system may include a control system and a working fluid circuit including a waste heat exchanger, an expansion device, a recuperator, a main pressurization device, and a heat exchanger assembly. The heat exchanger assembly may include a plurality of gas-cooled heat exchangers configured to transfer thermal energy from the working fluid to a cooling medium, a plurality of fans configured to direct the cooling medium into contact with the gas-cooled heat exchangers, and a plurality of drivers, each driver configured to drive a respective fan. The control system may be communicatively coupled to the heat exchanger assembly and configured to modulate a rotational speed of at least one fan to regulate a pressure of the working fluid at the inlet.