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 in a refrigeration circuit, controlled by a controller that adjusts the refrigerant charge based on measured subcooling values and operating modes, using inlet and outlet valves and a compressor discharge injection valve to regulate the working fluid quantity in the dynamic receiver.
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 compressor discharge temperature, suction pressure, and ambient conditions to dynamically modify the receiver filling degree, thereby adapting to different operating modes (full-load, part-load, transient) and eliminating the need for fixed filling compromises
Solution Approach 2:
The system employs feedback control mechanisms where sensors continuously monitor system performance parameters and feed this information to the controller. The controller processes this feedback and adjusts the receiver filling accordingly, creating a closed-loop system that optimizes efficiency across the entire operating map by responding to actual system conditions rather than relying on predetermined fixed settings
2Adaptability or versatility
If the refrigerant charge in the receiver is maintained at a fixed level, then the receiver structure can be simplified, but the operating map for the refrigeration system is limited
Solution Approach 1:
The dynamic receiver filling system serves multiple functions simultaneously: it optimizes system efficiency across different operating conditions, extends the viable operating map, provides transient response improvement, and maintains stability during load variations. This multi-functional approach justifies the added control complexity by delivering comprehensive system performance benefits that a simple fixed-level receiver cannot achieve
3Productivity
If dynamic control of refrigerant charge is implemented, then efficiency under both full-load and part-load conditions can be optimized, but the control system complexity increases
Solution Approach 1:
The system optimizes performance by dynamically changing key parameters including receiver filling degree, refrigerant charge level, and valve positioning based on operating conditions. The controller adjusts these parameters in real-time to maximize system efficiency across the full operating range, from full-load to part-load conditions, thereby achieving productivity improvement through controlled parameter variation
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 allows for more efficient operation by dynamically selecting optimal conditions for both full-load and part-load scenarios, expanding the operating map of the refrigeration system.
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
Figure 1A
Figure 1B
Figure 1C
AI summary
There is described a heating, ventilation, air conditioning, and refrigeration (HVACR) system 100, comprising a fluid circuit including: a compressor 102; a first heat exchanger 106; an expander 118; a second heat exchanger 110; characterized in that the HVACR system includes: a dynamic receiver 120, the dynamic receiver in parallel with the expander with respect to the fluid circuit; an inlet valve 122 positioned directly upstream of the dynamic receiver, the inlet valve downstream of the first heat exchanger and upstream of the second heat exchanger with respect to the fluid circuit; and an outlet valve 124 positioned directly downstream of the dynamic receiver, the outlet valve downstream of the first heat exchanger and upstream of the second heat exchanger with respect to the fluid circuit; and a controller 132 configured to control the inlet valve and the outlet valve, wherein 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, and when a quantity of working fluid stored in the dynamic receiver exceeds the target quantity, the controller is configured to reduce the quantity of working fluid stored in the dynamic receiver by opening the outlet valve until the target quantity of working fluid is stored in the dynamic receiver.