Refrigerant Buffer Tank Control for Variable Charge Cooling
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Solution Overview
Problem
Traditional refrigeration systems have a fixed refrigerant charge level, which is sub-optimal for varying operating conditions, leading to inefficiencies and reduced performance over time, as they cannot adjust refrigerant levels dynamically to match changing conditions.
Innovation Solution
A refrigeration system utilizing a buffer tank and controllable valves to vary refrigerant charge levels in the main refrigeration circuit based on sub-cooling measurements, allowing for efficient adjustments during changes in operating conditions and maintaining optimal performance by transferring refrigerant between the main circuit and the buffer tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed refrigerant charge level is used in traditional refrigeration systems, then the system structure is simple, but the system efficiency decreases under varying operating conditions
Solution Approach 1:
The patent applies dynamics by transforming the fixed refrigerant charge system into a dynamic adjustable system. A buffer tank is introduced to store additional refrigerant, and a control system with sensors and valves dynamically adjusts the refrigerant charge level in the main circuit based on real-time operating conditions such as temperature, pressure, and humidity, enabling the system to adapt efficiently to varying conditions without excessive structural complexity
Solution Approach 2:
The patent implements parameter changes by modifying the refrigerant charge level parameter dynamically. The control system monitors operating parameters and adjusts the refrigerant mass in the main circuit by transferring refrigerant between the buffer tank and main circuit, thereby optimizing system efficiency across different operating conditions through parameter variation rather than structural redesign
2Quantity of substance
If the refrigerant charge level is increased to improve cooling capacity, then the cooling capacity increases, but the system robustness decreases over time as refrigerant charge is depleted
Solution Approach 1:
The patent applies preliminary action by pre-storing additional refrigerant in the buffer tank before it is needed. This allows the system to quickly replenish refrigerant in the main circuit if depletion occurs, maintaining robustness without requiring a permanently oversized charge that would compromise efficiency. The buffer tank acts as a pre-prepared reservoir for emergency or extended operation
Solution Approach 2:
The buffer tank serves as an intermediary between the refrigerant supply and the main refrigeration circuit. It decouples the main circuit from direct refrigerant depletion issues by providing a buffer reservoir that can supply refrigerant when needed, thereby protecting the main circuit's operational reliability without requiring the main circuit to contain excessive refrigerant that would reduce efficiency
3Ease of operation
If traditional closed refrigeration circuits are used, then the system is simple to operate, but the refrigerant charge level cannot be adjusted for varying operating conditions
Solution Approach 1:
The patent implements self-service by enabling the refrigeration system to automatically adjust its own refrigerant charge level without external intervention. Sensors monitor operating conditions and trigger the control system to automatically transfer refrigerant between the buffer tank and main circuit as needed, maintaining optimal charge levels autonomously while preserving operational simplicity for the user
Solution Approach 2:
The patent applies feedback by implementing a closed-loop control system that continuously monitors operating parameters (temperature, pressure, humidity) and uses this feedback to automatically adjust the refrigerant charge level. The control system receives feedback from sensors and modulates refrigerant transfer accordingly, enabling adaptability while maintaining ease of operation through automation
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 efficiency, enlarges the operating envelope, and extends the system's robustness by dynamically adjusting refrigerant charge levels, ensuring optimal performance across different conditions and reducing maintenance needs.
Implementation Method 1
When a refrigerant pressure in the buffer tank is lower or higher than a refrigerant pressure in the main refrigeration circuit then opening the respective valve will allow for transfer of refrigerant fluid to or from the buffer tank
Implementation Method 2
the cooling of the refrigerant fluid is done via a heat rejection heat exchanger rejecting heat to the atmosphere and the heating of the refrigerant fluid is done via a heat absorbing heat exchanger that absorbs heat from an object to be cooled
Implementation Method 3
refrigeration or heating can be provided by a refrigeration system making use of the refrigeration cycle, in which a refrigerant fluid is compressed, cooled, expanded and then heated
Implementation Method 4
in which a refrigerant fluid is compressed, cooled, expanded and then heated
Data Source
Figure 1~2
AI summary
A refrigeration system comprises a main refrigeration circuit for holding refrigerant fluid, the main refrigeration circuit including: a compression device 12, a heat rejecting heat exchanger 14, an expansion device 18 and a heat absorbing heat exchanger 16. In addition, the refrigeration system includes a buffer tank 20 attached to the main refrigeration circuit, with valves 22, 24 for controlling flow of refrigerant fluid between the main refrigeration circuit and the buffer tank 20. The refrigeration system is arranged such that the valves 22, 24 are controlled to transfer refrigerant fluid between the main refrigeration circuit and the buffer tank 20 based on a measure of sub-cooling in the main refrigeration circuit. Via the use of a buffer tank 20 and controllable valves 22, 24 it becomes possible to vary the refrigerant charge level of the main refrigeration circuit in order to allow for increased efficiency during changes in operating conditions, as well as increased refrigerant capacity, the potential to enlarge the operating envelope of the refrigerant system, and other enhancements including greater robustness over time as refrigerant charge is depleted.