Refrigeration Cycle Bypass Flow Control for Continuous Heat Exchange
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses face challenges in continuously controlling the heat exchange capacity of the heat source side heat exchanger, particularly when the supply amount of the object to be heat exchanged cannot be continuously controlled from maximum to zero, leading to inefficiencies and the need for increased numbers of heat exchangers and solenoid valves.
Innovation Solution
A refrigeration cycle apparatus that utilizes a bypass piping system with a flow control device to distribute refrigerant and adjust the flow rate, allowing continuous control of the heat exchange capacity without increasing the number of heat exchangers, by distributing refrigerant in the bypass piping and varying the flow rate during stage transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple heat exchangers connected in parallel with multiple solenoid valves are used to control heat exchange capacity in stages, then the heat exchange capacity can be controlled in discrete stages, but the control cannot be continuous and the device complexity increases
Solution Approach 1:
The heat source side heat exchanger is divided into multiple independent heat exchangers connected in parallel, each capable of being independently controlled by solenoid valves. This segmentation allows discrete stage control of heat exchange capacity while maintaining a manageable system structure.
Solution Approach 2:
A flow control device is introduced to dynamically adjust the refrigerant flow rate in real-time, enabling continuous control of heat exchange capacity. This dynamic adjustment complements the discrete stage control of individual heat exchangers, achieving seamless capacity modulation without requiring excessive numbers of components.
2Adaptability or versatility
If the number of heat exchangers is increased to achieve continuous control, then the heat exchange capacity control range is improved, but the device complexity and number of solenoid valves increase
Solution Approach 1:
The flow control device serves multiple functions: it continuously adjusts refrigerant flow rate, bridges capacity gaps between discrete heat exchanger stages, and enables seamless transition between different capacity levels. This multi-functionality allows achieving continuous control with a limited number of heat exchangers and solenoid valves.
Solution Approach 2:
The system controls heat exchange capacity by changing multiple parameters: the on/off state of individual heat exchangers via solenoid valves, and the refrigerant flow rate via the flow control device. This multi-parameter control approach expands the effective control range without proportionally increasing the number of physical components.
3Device complexity
If discrete stage control is used without bypass piping, then the system structure is simpler, but the minimum capacity in high-capacity stages cannot be smaller than the maximum capacity in low-capacity stages
Solution Approach 1:
The bypass piping is pre-configured to provide an alternative refrigerant flow path that bypasses one or more heat exchangers. This preliminary structural arrangement enables the flow control device to adjust refrigerant flow rate independently, allowing the minimum capacity of a high-capacity stage to be reduced below the maximum capacity of a low-capacity stage, thus achieving continuous control.
Solution Approach 2:
The bypass piping acts as an intermediary element that decouples the refrigerant flow from the discrete heat exchanger stages. By providing this intermediate path, the system can smoothly transition between capacity levels, eliminating the discontinuity inherent in discrete stage control while maintaining relatively simple system structure.
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
Enables continuous control of the heat exchange capacity, ensuring that the minimum capacity in high-capacity stages is smaller than the maximum capacity in low-capacity stages, without increasing the number of heat exchangers, thus improving operational efficiency and reducing the need for additional solenoid valves.
Implementation Method 1
distributing refrigerant in the bypass piping and by continuously increasing or decreasing the flow rate of the refrigerant that is flowing in the bypass piping with a flow control device
Implementation Method 2
heat exchange is carried out in the first heat exchanger 24
Data Source
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AI summary
To obtain a refrigeration cycle apparatus that is capable of improving continuity of control of a heat exchange capacity of a heat source side heat exchanger. A refrigeration cycle apparatus (an air-conditioning apparatus) including a heat source side heat exchanger 3 having a first heat exchanger 24 and a second heat exchanger 25 connected in parallel; an air-sending device 18 that supplies air, which is an object to be heat exchanged in the first heat exchanger 24 and the second heat exchanger 25, in a variable manner. The refrigeration cycle apparatus further including solenoid valves 3a to 3d that each opens and closes a refrigerant passage of the first heat exchanger 24 and the second heat exchanger 25, a third refrigerant circuit 23 that is parallelly connected to the first heat exchanger 24 and the second heat exchanger 25, and a flow control valve 40 that controls the flow rate of the refrigerant flowing in the third refrigerant circuit 23.