Dynamic liquid receiver and control strategy
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Solution Overview
Problem
Refrigeration circuits with fixed liquid receiver filling settings face inefficiencies across different operating conditions and loads, requiring a compromise in efficiency across various parts of the operating map.
Innovation Solution
A dynamic liquid receiver system with a controller that adjusts the refrigerant charge based on measured subcooling values and operating modes, using inlet and outlet valves to regulate the working fluid quantity, allowing for optimized efficiency at both full-load and part-load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed receiver filling setting is used, then the system can maintain adequate efficiency across different parts of the operating map, but efficiency under specific operating conditions must be sacrificed
Solution Approach 1:
The patent implements a dynamic receiver filling system that adjusts the refrigerant charge level in the liquid receiver based on real-time operating conditions. The controller monitors parameters such as cooling load, outdoor temperature, and system pressure, then dynamically modifies the receiver filling percentage accordingly. This dynamic adjustment allows the system to optimize energy efficiency across varying operating conditions rather than being constrained by a fixed filling setting, directly resolving the contradiction between adaptability and energy efficiency.
2Productivity
If the refrigerant charge in the receiver is maintained at a fixed level, then the system structure remains simple, but efficiency cannot be optimized for both full-load and part-load conditions
Solution Approach 1:
The patent employs a feedback control mechanism where the controller continuously monitors system operating parameters including cooling load, outdoor temperature, and refrigerant pressures. Based on this feedback information, the controller dynamically adjusts the receiver filling level to optimize system efficiency. This feedback-driven approach enables the system to adapt to changing conditions and optimize performance across both full-load and part-load operations, while the control logic manages the complexity through systematic decision-making algorithms.
3Adaptability or versatility
If a fixed receiver filling setting is used, then the device complexity is low, but the operating map for the refrigeration system is limited
Solution Approach 1:
The patent transforms the static receiver filling approach into a dynamic system that can adapt to a broader range of operating conditions. By implementing dynamic adjustment of the receiver filling level based on real-time monitoring of cooling load, outdoor temperature, and system pressures, the system expands its effective operating map. This dynamic capability allows the refrigeration system to maintain optimal performance across diverse conditions including varying loads and ambient temperatures, thereby increasing operational versatility without requiring fundamentally different system architectures.
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 enables more efficient operation by dynamically adjusting the refrigerant charge, enhancing the system's performance across the operating map and improving efficiency in various modes.
Implementation Method 1
The first heat exchanger is configured to exchange heat between a working fluid in the fluid circuit and a first process fluid, the second heat exchanger is configured to exchange heat between the working fluid and a second process fluid, and the third heat exchanger is configured to exchange heat with ambient air
Implementation Method 2
a compressor
Implementation Method 3
an expander
Implementation Method 4
The controller is configured to determine a target quantity of working fluid to be stored in the dynamic receiver based on a measured liquid line subcooling value and a subcooling threshold value
Data Source
AI summary
A dynamic receiver is included in parallel to an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The dynamic receiver allows control of the refrigerant charge of the HVACR system to respond to different operating conditions. The dynamic receiver can be filled or emptied in response to the subcooling observed in the HVACR system compared to desired subcooling for various operating modes. The HVACR system can include a line directly conveying working fluid from compressor discharge to the dynamic receiver to allow emptying of the dynamic receiver to be assisted by injection of the compressor discharge.