Multi-Indoor Air Conditioner Leak Isolation for Faster Pump-Down
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Solution Overview
Problem
In air conditioners with multiple indoor heat exchangers connected in parallel and an outdoor heat exchanger in series, the pump-down operation to collect refrigerant after a leak detection takes longer due to the need to isolate and collect refrigerant from all indoor units simultaneously.
Innovation Solution
The air conditioner includes separate leak detectors and isolators for each indoor unit, allowing the controller to isolate and collect refrigerant from only the leaking unit while keeping others connected, thereby reducing the overall collection time by isolating non-leaking units from the refrigerant circuit during the pump-down operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant collection is performed from all indoor heat exchangers in parallel connection, then complete refrigerant recovery is achieved, but the pump-down operation time is excessively long
Solution Approach 1:
The patent divides the refrigerant collection process into separate segments for each indoor heat exchanger. Instead of collecting refrigerant from all indoor units simultaneously, the system performs collection operations sequentially for each segmented indoor unit, reducing the overall pump-down time while ensuring complete refrigerant recovery from the leaking unit.
Solution Approach 2:
The patent implements dynamic control of isolation valves based on real-time leak detection results. The system dynamically adjusts which indoor heat exchangers are isolated and which remain connected to the refrigerant circuit, optimizing the pump-down operation by collecting refrigerant only from units that require it rather than isolating all indoor units.
2Loss of substance
If all indoor heat exchangers are isolated during pump-down operation, then refrigerant collection is thorough, but the operation time increases significantly
Solution Approach 1:
The patent applies local quality control by isolating only the specific indoor heat exchanger where a leak is detected, rather than isolating all indoor units uniformly. This localized approach ensures thorough refrigerant collection from the leaking unit while maintaining normal operation and shorter pump-down time for non-leaking units.
Solution Approach 2:
The system dynamically determines which indoor heat exchangers require isolation based on leak detection results. The isolation valves are controlled dynamically to match the actual leak location, optimizing both refrigerant recovery completeness and pump-down operation time by avoiding unnecessary isolation of healthy units.
Data Source
AI summary
An air conditioner that includes a refrigerant circuit connecting a plurality of indoor heat exchangers in parallel and is able to complete collection of refrigerant to the side of an outdoor heat exchanger in a shorter time when the refrigerant has leaked at any indoor heat exchanger is provided. Thus, in the air conditioner according to the present invention, when refrigerant leak is detected by a refrigerant leak sensor provided in an indoor unit and refrigerant leak is not detected by a refrigerant leak sensor provided in an indoor unit, an indoor LEV and a cutoff valve are closed to isolate an indoor heat exchanger of the indoor unit from the refrigerant circuit in a refrigerant pump-down operation. When refrigerant leak is detected by the refrigerant leak sensor and refrigerant leak is not detected by the refrigerant leak sensor, an indoor LEV and a cutoff valve are closed.