Air Conditioner Refrigerant Amount Estimation During Operation
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Solution Overview
Problem
It is challenging to estimate the remaining refrigerant amount in a refrigerant circuit of an air conditioner when it is actually operating, as achieving the default state required by existing methods is difficult.
Innovation Solution
The air conditioner includes a refrigerant circuit with an acquisition unit, storage unit, estimation model, detection unit, and control unit that regularly acquires and stores operating state quantities, detects stability conditions, and estimates the refrigerant amount using these quantities through regression models during cooling and heating operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the default state (super-cooled liquid refrigerant only) is used for refrigerant amount estimation, then the estimation method is simple, but it is difficult to achieve this state during actual operation
Solution Approach 1:
The patent changes the parameters used for estimation from requiring a specific refrigerant state (super-cooled liquid only) to using multiple operating state quantities (temperatures, pressures, flow rates) that can be measured during normal operation. This allows the estimation method to work under various operating conditions without needing to force the system into a specific state.
Solution Approach 2:
The patent transitions from a static estimation approach (requiring a fixed default state) to a dynamic approach that continuously monitors multiple operating parameters and adapts the estimation based on current system conditions. This enables accurate estimation during actual operation where conditions constantly change.
2Measurement precision
If multiple operating state quantities are collected and stability conditions are detected, then the refrigerant amount estimation accuracy is improved, but the system complexity increases
Solution Approach 1:
The control unit already performs these measurement and processing functions as part of normal air conditioner operation. The system uses its existing sensors and control capabilities to collect operating state quantities and detect stability conditions, rather than adding dedicated hardware for refrigerant estimation. This leverages the system's self-monitoring capabilities.
Solution Approach 2:
The control unit serves multiple functions: it controls the air conditioner operation, monitors operating parameters for control decisions, and now also performs refrigerant amount estimation. By making the control unit multi-functional, the patent avoids adding separate dedicated systems while improving estimation accuracy.
3Productivity
If operating state quantities are acquired during actual operation, then the refrigerant amount can be estimated in real operation, but the stability conditions are harder to maintain
Solution Approach 1:
The patent implements periodic detection of stability conditions and periodic updating of refrigerant amount estimates. Rather than requiring continuous perfect stability, the system checks stability at regular intervals and performs estimation when conditions are favorable, accommodating the dynamic nature of actual operation while maintaining estimation accuracy.
Solution Approach 2:
The patent detects multiple types of stability conditions (first stability condition and second stability condition) and uses whichever is satisfied. By providing multiple stability criteria, the system increases the probability that at least one condition will be met during operation, ensuring continuous estimation capability even when individual conditions are hard to maintain.
Data Source
AI summary
An air conditioner includes a refrigerant circuit that is formed by connecting an indoor unit to an outdoor unit, where the circuit is filled with a predetermined amount of a refrigerant. The conditioner includes an obtainer that regularly acquires an operating state quantity at a time of air conditioning operation, a storage that stores therein the quantity that is acquired, a model that estimates a refrigerant remaining amount in the circuit by using the quantity, a detector that detects one of a first quantity being an operating state quantity in a state in which the circuit meets a first condition and a second quantity being an operating state quantity in a state in which the circuit meets a second condition that is different from the first condition, and a controller that estimates the remaining refrigerant amount in the circuit by using the model and the detected quantity.