Refrigeration Cycle Valve Control for Compressor Heating and Defrost
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Solution Overview
Problem
Existing air-conditioning systems face issues with refrigerant accumulation and power loss due to insufficient heating during compressor stoppage, and hot-water heaters experience water stagnation and freezing during defrosting operations, with no prior solutions addressing these problems effectively.
Innovation Solution
A refrigeration cycle device with a first and second solenoid valve, a four-way valve, outdoor and indoor heat exchangers, and a controller that manages the flow of refrigerant to prevent accumulation and seize the drive shaft by controlling the solenoid valves and heating the compressor shell, ensuring efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater is disposed along the outer periphery of a compressor to heat refrigerant and prevent refrigerant accumulation, then refrigerant retention is prevented, but power loss due to overheating occurs and sufficient heat may not be supplied
Solution Approach 1:
A heat transfer tube is introduced as an intermediary element inside the compressor cylinder, allowing direct heat transfer from the heater to the refrigerant without requiring the heater to be in direct contact with the refrigerant or compressor housing. This mediator enables efficient thermal coupling while preventing overheating of surrounding components.
Solution Approach 2:
The heating method transitions from external peripheral heating to internal direct heating through the heat transfer tube, changing the temperature distribution parameters within the compressor. This allows precise control of heating intensity and location, ensuring sufficient heat supply to the refrigerant while avoiding excessive temperature rise in other areas.
2Reliability
If backflow prevention mechanisms and flow blocking mechanisms are added to block refrigerant flow toward the compressor, then refrigerant accumulation is prevented, but device complexity increases
Solution Approach 1:
The invention extracts and eliminates the need for separate backflow prevention mechanisms and flow blocking mechanisms by integrating their functionality into the existing solenoid valve control system. The solenoid valve, already present for refrigerant flow control, is repurposed to also prevent refrigerant accumulation during compressor stoppage, thereby removing redundant components.
Solution Approach 2:
The solenoid valve is given multiple functions: it controls refrigerant flow during normal operation and simultaneously prevents refrigerant accumulation during compressor stoppage. This multi-functionality eliminates the need for dedicated backflow prevention and flow blocking mechanisms, reducing device complexity while maintaining reliability.
3Reliability
If water is circulated in the water heat exchanger during defrosting operation to prevent freezing, then water freezing is prevented, but water stagnation occurs in passages and freezing may still occur when water temperature drops to 0°C
Solution Approach 1:
Instead of continuous water circulation, the invention implements periodic water circulation during defrosting operation. Water is circulated at specific intervals and for specific durations, which is sufficient to prevent freezing in most passages while allowing brief stagnation periods that minimize energy consumption and reduce the risk of freezing in critical areas.
Solution Approach 2:
The system performs preliminary heating of water before circulation during defrosting operation, ensuring water temperature remains above freezing point. This preliminary action prevents water from reaching 0°C in stagnant passages, eliminating the freezing risk while allowing more flexible circulation control.
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
Prevents refrigerant retention and compressor malfunction while reducing power consumption by effectively managing refrigerant flow and heating, thereby enhancing energy efficiency and preventing water freezing in heat exchangers.
Implementation Method 1
heating means for heating a shell of the compressor
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A refrigeration cycle device includes a first refrigerant passage in which a compressor, a first solenoid valve, a four-way valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator are sequentially connected through pipes; a second refrigerant passage in which a second solenoid valve and a water refrigerant heat exchanger are sequentially connected to a pipe that connects a portion of a pipe between the compressor and the first solenoid valve to the pressure reducing device; heating means for heating a shell of the compressor; and a controller that performs control so as to close the first solenoid valve and the second solenoid valve in association with an operation of the compressor being stopped and so as to open the first solenoid valve when the heating means heats the compressor.