Refrigeration device
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Solution Overview
Problem
The utilization-side expansion valve in refrigeration apparatuses, when configured as a temperature-sensitive expansion valve, cannot be optionally regulated, leading to inconsistent refrigerant flow between the liquid interconnecting pipe and the utilization-side heat exchanger, which hinders defrosting operations.
Innovation Solution
Incorporating a bypass pipe and a switching mechanism that allows the refrigerant to bypass the temperature-sensitive utilization-side expansion valve, enabling optional flow between the liquid interconnecting pipe and the utilization-side heat exchanger, and a controller to manage the switching mechanism during defrosting to ensure efficient defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a temperature sensitive expansion valve is used, then the valve opening is automatically regulated according to temperature, but the valve cannot be optionally regulated and refrigerant flow cannot be controlled for defrosting operations
Solution Approach 1:
The refrigerant flow path is segmented into two separate channels: a main channel through the temperature-sensitive expansion valve for normal cooling operation, and a bypass channel for defrosting operation. This segmentation allows the system to independently control refrigerant flow for different operational modes without interfering with each other.
Solution Approach 2:
A four-way switching valve acts as an intermediary device that directs refrigerant flow between the main channel and bypass channel. This mediator enables the system to switch between automatic temperature-regulated flow and optional defrosting flow, resolving the contradiction between automatic regulation and optional control.
2Reliability
If the expansion valve opening is fixed by temperature sensitivity, then automatic temperature control is achieved, but refrigerant cannot flow from gas interconnecting pipe to liquid interconnecting pipe via heat exchanger during defrosting
Solution Approach 1:
The system dynamically switches between two operational states: during cooling operation, the four-way valve directs refrigerant through the temperature-sensitive expansion valve for automatic temperature control; during defrosting operation, the valve redirects refrigerant through the bypass channel, allowing high-temperature refrigerant to flow from the gas interconnecting pipe through the heat exchanger to the liquid interconnecting pipe.
3Adaptability or versatility
If a bypass channel is added for defrosting, then defrosting capability is improved, but device complexity increases
Solution Approach 1:
The four-way switching valve, originally designed for directional control in heat pump systems, is utilized for dual purposes: controlling refrigerant flow direction during cooling/heating modes and enabling bypass flow during defrosting mode. This multi-functionality reduces the need for additional dedicated defrosting components, thereby limiting the increase in device complexity.
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 effective defrosting of the utilization-side heat exchanger using high-temperature and high-pressure refrigerant, accelerating the defrosting process and maintaining refrigerant flow rates, while preventing leaks.
Implementation Method 1
a temperature sensitive utilization-side expansion valve (53)
Implementation Method 2
the refrigerant absorbs heat from inside air in the utilization-side heat exchanger to evaporate
Implementation Method 3
the refrigerant absorbs heat from inside air in the utilization-side heat exchanger
Implementation Method 4
the refrigerant dissipates heat in the utilization-side heat exchanger to condense
Implementation Method 5
the refrigerant dissipates heat in the utilization-side heat exchanger
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A utilization-side unit (12) includes a utilization-side heat exchanger (51) and an expansion valve circuit portion (52). The expansion valve circuit portion (52) includes: a temperature sensitive utilization-side expansion valve (53); a main pipe (60) allowing a refrigerant to flow between the utilization-side expansion valve (51) and the liquid interconnecting pipe (13) via the utilization-side expansion valve (53); a bypass pipe (70) allowing the refrigerant to bypass the main pipe (60) and flow between the utilization-side heat exchanger (51) and the liquid interconnecting pipe (13); and a switching mechanism (54) switching each of the main pipe (60) and the bypass pipe (70) between an open state and a closed state.