Refrigeration cycle apparatus
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Solution Overview
Problem
Existing air-conditioning apparatuses face reliability issues due to liquid refrigerant suction by the compressor, leading to inefficient oil return and two-layer separation, especially at low temperatures, which complicates the accumulator structure and installation.
Innovation Solution
A refrigeration cycle apparatus with a liquid-level sensing device and controller that adjusts the compressor suction based on the liquid level in the accumulator, reducing suction when the level is high to prevent liquid return and improve start-up characteristics without increasing the accumulator's complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot gas bypass is introduced into the bottom of the tank to improve oil return efficiency, then compressor reliability is improved, but the accumulator structure becomes complex and installation becomes complicated
Solution Approach 1:
The patent extracts the hot gas injection function from the accumulator structure itself and relocates it to the refrigerant circuit. By introducing a hot gas injection valve and control mechanism in the refrigerant circuit, the accumulator can maintain its simple tank structure while still achieving the beneficial effect of hot gas injection for oil return.
Solution Approach 2:
The patent introduces a hot gas injection valve as an intermediary component in the refrigerant circuit to mediate the hot gas delivery to the accumulator. This intermediary mechanism allows hot gas to be injected into the accumulator bottom without requiring direct structural integration, thus maintaining simplicity while achieving the desired oil return effect.
2Reliability
If a bypass is added to introduce hot gas into the accumulator bottom, then liquid return to compressor is reduced, but the device complexity increases
Solution Approach 1:
The patent makes the refrigerant circuit universal by enabling it to perform both the primary refrigeration function and the secondary hot gas injection function. The hot gas injection valve and control mechanism allow the refrigerant circuit to serve dual purposes, eliminating the need for separate dedicated structures and reducing overall device complexity.
Solution Approach 2:
The patent merges the hot gas injection function with the existing refrigerant circuit components. By combining these functions through strategic placement of the hot gas injection valve and control mechanisms within the refrigerant circuit, the system achieves compressor protection without adding separate independent systems, thus reducing overall complexity.
3Ease of manufacture
If the accumulator tank structure is simplified, then ease of manufacture and installation is improved, but the ability to efficiently return oil to compressor is reduced
Solution Approach 1:
The patent replaces the mechanical structural complexity (bypass pipes, injection holes in the tank) with a controllable valve mechanism in the refrigerant circuit. This substitution allows the accumulator tank to remain structurally simple and easy to manufacture, while the electronically controlled hot gas injection valve provides precise control over the oil return process.
Solution Approach 2:
The patent utilizes parameter changes in the refrigerant circuit (temperature, pressure, flow rate) to achieve oil return control. By monitoring and adjusting these parameters through the control mechanism, the system can efficiently manage oil return without requiring complex structural modifications to the accumulator tank, thus maintaining ease of manufacture.
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 compressor reliability and start-up efficiency by reducing liquid return and two-layer separation, maintaining system performance without complicating the accumulator's structure.
Implementation Method 1
a liquid-level sensing device (15) provided to the accumulator (14) and configured to sense a liquid level of the liquid refrigerant stored in the accumulator (14)
Implementation Method 2
in a case in which the liquid level sensed by the liquid-level sensing device (15) is higher than a threshold, the controller (3) performs a limiting operation of reducing an amount of suction of the gas refrigerant that is sucked from the accumulator (14) into the compressor (11)
Data Source
AI summary
A refrigeration cycle apparatus includes a refrigerant circuit in which a compressor, a first heat exchanger, a first expansion device, a second expansion device, and a second heat exchanger are connected by refrigerant pipes and through which refrigerant circulates, an accumulator provided to the refrigerant circuit, formed to store liquid refrigerant, and from which gas refrigerant is caused to be sucked into the compressor, a liquid-level sensing device provided to the accumulator and sensing a liquid level of the liquid refrigerant stored in the accumulator, and a controller performs, in a case in which the liquid level sensed by the liquid-level sensing device is higher than a threshold, a limiting operation of reducing an amount of suction of the gas refrigerant that is sucked from the accumulator into the compressor and, in a case in which the liquid level is lower than or equal to the threshold, a normal operation.