Refrigeration cycle apparatus
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Solution Overview
Problem
The provision of an accumulator in refrigeration cycle apparatuses suppresses liquid compression but deteriorates the oil return property, reducing the reliability of the compressor and decreasing the degree of suction dryness.
Innovation Solution
Incorporating a refrigerant circuit with a compressor, first and second heat exchangers, a decompressing apparatus, an accumulator, and a heating unit that includes a third heat exchanger to perform heat exchange between refrigerant streams, thereby improving oil return and maintaining compressor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an accumulator is provided in the refrigerant circuit, then liquid compression is suppressed, but oil return property from the accumulator is deteriorated
Solution Approach 1:
A heating unit is introduced as an intermediary component between the accumulator and compressor. This heating unit heats the refrigerant before it enters the compressor, improving oil return property without compromising the accumulator's liquid compression prevention function. The heating unit acts as a mediator that resolves the contradiction by adding a new component that addresses the oil return issue while preserving the accumulator's protective role.
2Reliability
If an accumulator is provided in the refrigerant circuit, then liquid compression is suppressed, but degree of suction dryness of the compressor is decreased
Solution Approach 1:
The heating unit serves as a mediator that heats the refrigerant between the accumulator and compressor inlet. This heating process increases the degree of suction dryness by evaporating any remaining liquid refrigerant, thereby improving compressor performance while maintaining the accumulator's function of preventing liquid compression.
Solution Approach 2:
The temperature parameter of the refrigerant is changed by introducing the heating unit. By heating the refrigerant to a higher temperature before it enters the compressor, the refrigerant's state is altered from potentially wet to dry, thus improving compressor performance without sacrificing the reliability benefits of the accumulator.
3Reliability
If an accumulator is provided in the refrigerant circuit, then liquid compression is suppressed, but surplus refrigerant stays in the accumulator
Solution Approach 1:
The heating unit performs a preliminary action by heating the refrigerant before it enters the compressor. This pre-heating causes surplus refrigerant in the accumulator to be vaporized and converted to gas phase, reducing the amount of liquid refrigerant remaining in the accumulator while maintaining the protective function against liquid compression.
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
The solution effectively avoids liquid compression in the compressor, enhances the oil return property, and improves the reliability and performance of the refrigeration cycle apparatus.
Implementation Method 1
a heating unit configured to heat the refrigerant that returns from the accumulator to the compressor, using the refrigerant that has passed through the first heat exchanger
Data Source
AI summary
A refrigeration cycle apparatus includes: a refrigerant circuit including a compressor, a first heat exchanger, a first decompressing apparatus, a second heat exchanger, and an accumulator; and a heating unit. In the refrigerant circuit, refrigerant circulates in order of the compressor, the first heat exchanger, the first decompressing apparatus, the second heat exchanger, and the accumulator. The heating unit is configured to heat the refrigerant that returns from the accumulator to the compressor, using the refrigerant that has passed through the first heat exchanger. Preferably, the heating unit includes a third heat exchanger configured to perform heat exchange between the refrigerant running toward the first decompressing apparatus after having passed through the first heat exchanger and the refrigerant running toward the compressor after having passed through the accumulator.