Heat source unit and refrigeration cycle apparatus
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Solution Overview
Problem
The use of refrigerants containing at least 1,2-difluoroethylene in refrigeration cycle apparatuses poses a risk of damage to existing connection pipes due to pressure exceeding their withstanding limits, as existing systems are not designed to handle these refrigerants effectively.
Innovation Solution
Designing a heat source unit with a compressor and heat source-side heat exchanger, connected via a connection pipe, where the refrigerant used is at least 1,2-difluoroethylene, and setting the design pressure of the heat source unit lower than 1.5 times the design pressure of the connection pipe to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a refrigerant containing 1,2-difluoroethylene is used to achieve low GWP, then global warming potential is reduced, but the operating pressure may exceed the withstanding pressure of existing connection pipes causing damage
Solution Approach 1:
The patent changes the pressure parameter by designing the heat source unit with a design pressure lower than 1.5 times the design pressure of the connection pipe. This parameter adjustment ensures that the operating pressure remains within the safe withstanding pressure of existing connection pipes while still using low-GWP refrigerants containing 1,2-difluoroethylene
2Adaptability or versatility
If existing connection pipes are used with new low-GWP refrigerants, then system compatibility is maintained, but the pipes may be damaged due to excessive pressure
Solution Approach 1:
The patent adjusts the pressure parameter by setting the heat source unit's design pressure to be less than 1.5 times the connection pipe's design pressure. This allows the system to use various low-GWP refrigerants (maintaining adaptability) while controlling the operating pressure to prevent pipe damage
Solution Approach 2:
The patent applies beforehand cushioning by designing the heat source unit with a pressure limit that is lower than the connection pipe's withstanding pressure (specifically, design pressure < 1.5 × pipe design pressure). This creates a safety margin before the pipe's pressure limit is reached, preventing damage even when using high-pressure low-GWP refrigerants
3Reliability
If the design pressure of the heat source unit is reduced to protect connection pipes, then pipe damage is prevented, but system performance may be limited
Solution Approach 1:
The patent optimizes the pressure parameter by setting the heat source unit's design pressure to be lower than 1.5 times the connection pipe's design pressure. This balanced parameter setting protects connection pipes from damage while maintaining sufficient system performance for refrigeration and heat pump operations
Data Source
AI summary
A heat source unit and a refrigeration cycle apparatus that are able to reduce damage to a connection pipe when a refrigerant containing at least 1,2-difluoroethylene is used are provided. An outdoor unit (20) that is connected via a liquid-side connection pipe (6) and a gas-side connection pipe (5) to an indoor unit (30) including an indoor heat exchanger (31) and that is a component of an air conditioner (1) includes a compressor (21) and an outdoor heat exchanger (23). A refrigerant containing at least 1,2-difluoroethylene is used as a refrigerant. A design pressure of the outdoor unit (20) is lower than 1.5 times a design pressure of each of the liquid-side connection pipe (6) and the gas-side connection pipe (5).