Economizer Pressure Control in Vapor Compression Compressors
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Solution Overview
Problem
Conventional vapor compression systems lack independent control over economizer operating pressure and flow rate, leading to inefficient operation and design constraints, especially when introducing gaseous refrigerant from flash tanks into single-stage compressors.
Innovation Solution
A controller system that monitors and adjusts the economizer operating pressure and flow rate through a control algorithm, allowing for independent control of the economizer circuit and enabling efficient operation by managing the pressure between the evaporator and condenser pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an economizer circuit with flash tank is added to vapor compression system, then cooling capacity and system efficiency are improved, but device complexity and control difficulty increase
Solution Approach 1:
The patent implements a controller that continuously monitors economizer operating pressure and adjusts the economizer expansion device accordingly. This feedback control mechanism automatically maintains optimal operating conditions, resolving the control difficulty introduced by the flash tank economizer circuit while preserving the cooling capacity benefits.
2Ease of operation
If economizer operating pressure is dictated by overall system conditions, then system operation is simplified, but independent control of economizer pressure and flow rate is lost
Solution Approach 1:
The patent introduces a dynamic control system that can independently adjust economizer operating pressure and flow rate based on varying system conditions. The controller modifies expansion device positioning in real-time, enabling the economizer circuit to adapt to different operating scenarios while maintaining overall system coordination.
Solution Approach 2:
The controller uses feedback from pressure sensors to automatically regulate economizer operating pressure, providing independent control capability while maintaining simplified operation through automated adjustment rather than manual intervention.
3Adaptability or versatility
If gaseous refrigerant from flash tank is introduced to single-stage compressor, then economizer circuit functionality is achieved, but compressor performance and reliability deteriorate
Solution Approach 1:
The controller monitors economizer operating pressure and adjusts the expansion device to ensure that the amount and pressure of gaseous refrigerant returned to the compressor remain within safe operating parameters, preventing compressor damage while maintaining economizer functionality.
Solution Approach 2:
The system dynamically adjusts economizer operating pressure and refrigerant flow parameters to optimize the balance between economizer performance and compressor protection, ensuring reliable operation when integrating flash tank economizer with single-stage compressor.
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 solution enhances the efficiency and flexibility of vapor compression systems by allowing independent control of the economizer circuit, improving cooling capacity and overall system performance.
Implementation Method 1
a first expansion device can expand the refrigerant from condenser pressure to an intermediate pressure between condenser pressure and evaporator pressure, resulting in the flashing of some of the refrigerant to a vapor
Implementation Method 2
refrigerant gas compressed by a compressor and passed to a condenser where it exchanges heat with another fluid, for example, air or water, and is condensed to a liquid
Implementation Method 3
the refrigerant exchanges heat with another fluid, for example, air or water, and is condensed to a liquid
Implementation Method 4
the refrigerant exchanges heat with another fluid, for example, air or water, and is evaporated to a gas
Implementation Method 5
the refrigerant exchanges heat with another fluid, for example, air or water, and is evaporated to a gas
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A method and system for controlling operation of a vapor compression system (13) includes monitoring at least one component condition of the system (13), comparing a predetermined setpoint to the at least one component condition, and loading or unloading at least one of a first compressor (18) or a second compressor (20) of the system (13) in response to the comparison of the predetermined setpoint to the at least one component condition.