External Expansion Valve Layout for Quieter Indoor Air Conditioners
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Solution Overview
Problem
Air conditioning apparatuses with liquid pressure adjusting expansion valves experience noise issues due to refrigerant flowing in a gas-liquid two-phase state, which increases noise levels in the indoor unit.
Innovation Solution
The introduction of an external expansion valve in the liquid refrigerant connection pipe to reduce the pressure of the refrigerant further, minimizing noise by relocating the noise source away from the indoor unit or using sound deadening materials, and strategically positioning the external expansion valve to reduce noise transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a liquid pressure adjusting expansion valve is provided in the outdoor liquid refrigerant pipe to reduce refrigerant pressure to a gas-liquid two-phase state, then refrigerant circulation efficiency is improved, but noise from the indoor unit increases due to two-phase refrigerant flowing through the indoor expansion valve
Solution Approach 1:
The patent divides the pressure reduction process into two separate stages: first, the liquid pressure adjusting expansion valve in the outdoor unit reduces pressure to create two-phase refrigerant; second, an additional expansion valve in the liquid refrigerant connection pipe further reduces pressure. This segmentation allows the noisy two-phase flow to occur in the outdoor unit rather than the indoor unit, resolving the noise problem while maintaining refrigeration efficiency.
Solution Approach 2:
The patent extracts the noise-generating function (pressure reduction of two-phase refrigerant) from the indoor unit and relocates it to the liquid refrigerant connection pipe. By placing an expansion valve in the connection pipe between the outdoor and indoor units, the harmful noise-generating process is separated from the indoor environment, eliminating the noise source from the indoor unit while preserving the necessary refrigerant pressure adjustment.
2Object-generated harmful factors
If an external expansion valve is added to the liquid refrigerant connection pipe to further reduce refrigerant pressure, then noise from the indoor unit is reduced, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary component (expansion valve in the liquid refrigerant connection pipe) that mediates between the outdoor unit's liquid pressure adjusting expansion valve and the indoor unit. This intermediary performs the additional pressure reduction needed to eliminate indoor noise, acting as a bridge that transfers the noise-generating function away from the indoor unit while maintaining system functionality.
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 effectively reduces noise from the indoor unit by managing the pressure reduction of the refrigerant in the gas-liquid two-phase state, either through external expansion valves or sound deadening materials, thereby minimizing noise transmission to the indoor unit.
Implementation Method 1
a liquid pressure adjusting expansion valve that reduces the pressure of refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state
Implementation Method 2
providing the sound deadening material on the expansion valve in the liquid refrigerant connection pipe
Data Source
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AI summary
To reduce noise coming from an indoor unit in an air conditioning apparatus that has an outdoor unit that has a compressor and an outdoor heat exchanger, the indoor unit that has an indoor heat exchanger, and a liquid refrigerant connection pipe and a gas refrigerant connection pipe that interconnect both units and in which a liquid pressure adjusting expansion valve that reduces a pressure of a refrigerant flowing through the liquid refrigerant connection pipe in such a way that the refrigerant is in a gas-liquid two-phase state is provided in an outdoor liquid refrigerant pipe that interconnects the liquid-side end of the outdoor heat exchanger and the liquid refrigerant connection pipe. An external expansion valve unit (4a, 4b) having an external expansion valve (71a, 71b) that further reduces the pressure of the refrigerant whose pressure has been reduced in the liquid pressure adjusting expansion valve (26) is provided in the outdoor liquid refrigerant pipe (34).