Refrigerant cycle system and method
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Solution Overview
Problem
Existing refrigerant cycle systems lack a systematic approach to arrange refrigerant shut-off units effectively, particularly when multiple utilization-side units are involved, which can lead to unsafe refrigerant concentrations in case of leakage.
Innovation Solution
A method to determine and fix the length and internal volume of connection pipes in a refrigerant cycle system based on the capabilities of multiple utilization-side units, using tables to restrict pipe lengths and ensure safe refrigerant concentration limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant shut-off unit is disposed close to the utilization-side unit group, then the response time for blocking refrigerant leakage is improved, but the arrangement flexibility and installation freedom are reduced
Solution Approach 1:
The patent changes the parameter of connection pipe length from a fixed constraint to a calculated value based on refrigerant volume. By establishing a maximum allowable length Lmax derived from the refrigerant volume V and safety concentration C, the system allows flexible shut-off unit placement while ensuring safety. This transforms the rigid spatial constraint into a calculable parameter that balances both reliability and adaptability.
2Ease of manufacture
If the connection pipe length is increased to provide installation flexibility, then the ease of installation is improved, but the refrigerant accumulation risk increases
Solution Approach 1:
The patent applies preliminary action by calculating and establishing the maximum connection pipe length Lmax before actual installation. Using the formula Lmax = (V × C) / (π × d²/4), the system pre-determines the safe pipe length based on refrigerant volume, safety concentration requirements, and pipe diameter. This preliminary calculation ensures that installation flexibility is achieved without compromising safety, as the length constraint is set in advance to prevent flammable refrigerant accumulation.
3Quantity of substance
If the connection pipe internal volume is reduced to minimize refrigerant quantity, then the refrigerant leakage amount is reduced, but the pipe dimensions are constrained
Solution Approach 1:
The patent transforms the pipe dimension selection from a fixed specification choice to a flexible parameter set by the safety requirements. The internal volume is controlled through the calculated maximum length Lmax and selected diameter d, where the product (Lmax × π × d²/4) equals the allowable refrigerant volume. This allows engineers to select different pipe diameters and corresponding lengths while maintaining the same safety-equivalent refrigerant volume, thus preserving adaptability while minimizing refrigerant quantity.
Data Source
AI summary
An air conditioning apparatus includes utilization-side units each including a first refrigerant circuit, a heat source-side unit including a second refrigerant circuit, a connection pipe group, and a relay unit. The relay unit is disposed between the first refrigerant circuit and the second refrigerant circuit, and blocks a flammable refrigerant flowing through the connection pipe group. The utilization-side units are disposed in a utilization-side unit group that is a group of two or more utilization-side units. The relay unit blocks a flow of the refrigerant between the first refrigerant circuit and the second refrigerant circuit. The connection pipe group connects the first refrigerant circuit and the refrigerant shut-off unit. The connection pipe group has one or both of a length and an internal volume, which is fixed based on information on capabilities of the two utilization-side units.