Refrigerant Flow Path Switching for Heat Exchanger Capacity Control
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Solution Overview
Problem
Conventional air conditioners fail to control the capacity of the heat exchanger effectively during high-outside-temperature heating, low-outside-temperature cooling, and low-capacity cooling/heating operations, leading to inefficiencies and potential compressor start-stop issues.
Innovation Solution
A refrigeration cycle apparatus featuring a compressor, flow path switching device, first and second heat exchangers, and a flow path changing device that allows for switching between series and parallel connections of the heat exchangers to control refrigerant flow, enabling adaptive heat exchanger capacity management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two unit flow paths are connected in series during cooling operation and in parallel during heating operation, then the basic cooling and heating functions are achieved, but the heat exchanger capacity cannot be controlled during high-outside-temperature heating, low-outside-temperature cooling, and low-capacity operations
Solution Approach 1:
The first heat exchanger is divided into two independent flow paths (first flow path and second flow path), each capable of being controlled separately. This segmentation allows the system to adjust the effective heat exchange capacity by selectively opening or closing specific flow paths, thereby resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The patent introduces dynamic control capabilities through expansion valves (first expansion valve and second expansion valve) that can independently regulate refrigerant flow in each flow path. This dynamic adjustment enables the heat exchanger capacity to adapt to varying operating conditions such as high-outside-temperature heating and low-capacity operations, while maintaining a relatively simple fixed structural configuration.
2Reliability
If the heat exchanger capacity is fixed, then the device structure remains simple, but the compressor experiences frequent start-stop operations during varying operational conditions
Solution Approach 1:
By segmenting the heat exchanger into controllable flow paths with independent expansion valves, the system can modulate heat exchange capacity to match compressor output, preventing compressor short-cycling and improving operational reliability without requiring an overly complex control system.
Solution Approach 2:
The patent changes the operational parameters of the heat exchanger by controlling refrigerant flow distribution through multiple expansion valves. This allows continuous adjustment of heat exchange capacity to match varying compressor outputs, ensuring stable compressor operation across different operating conditions.
3Temperature
If the heat exchanger capacity is increased to handle high-outside-temperature heating, then the system can maintain heating performance, but the system becomes inefficient during low-capacity cooling/heating operations
Solution Approach 1:
The segmented flow path structure with independent control allows the system to activate only the necessary heat exchange capacity for each operating condition. During low-capacity operations, only one flow path may be active, reducing energy waste. During high-outside-temperature heating, both flow paths can be activated to maintain adequate heating performance.
Solution Approach 2:
The system employs partial action by selectively activating one or two flow paths based on heating or cooling demands. This avoids the energy inefficiency of using full heat exchanger capacity when only partial capacity is needed, while ensuring sufficient capacity is available when required for high-outside-temperature heating.
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 configuration allows for efficient control of the heat exchanger capacity, improving performance during varied operational conditions, reducing compressor start-stop frequency, and expanding the operating range of the air conditioner.
Implementation Method 1
a compressor (1) which compresses refrigerant
Implementation Method 2
a first heat exchanger (4) having a first heat exchange unit (4a) and a second heat exchange unit (4b)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A refrigeration cycle apparatus includes a compressor (1), a flow path switching device (2), a first heat exchanger (4) having a first heat exchange unit (4a) and a second heat exchange unit (4b), a flow path changing device (10), a first expansion valve (8a), and a second heat exchanger (9). The flow path switching device is configured to switch flow of the refrigerant compressed by the compressor between flow to the first heat exchanger and flow to the second heat exchanger. The flow path changing device is configured to switch flow of the refrigerant among flow successively through the first heat exchange unit and the second heat exchange unit, flow in parallel through the first heat exchange unit and the second heat exchange unit, and flow through any one of the first heat exchange unit and the second heat exchange unit. This allows the flow path changing device to switch between the first heat exchange unit and the second heat exchange unit, controlling the capacity of the first heat exchanger. Thus, the capacity of the heat exchanger can be controlled in accordance with the operation during high-outside-temperature heating, low-outside-temperature cooling, and low-capacity cooling/heating.