Air-conditioning apparatus and method of controlling the same
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Solution Overview
Problem
The degree of discharge superheat of compressors in air-conditioning apparatuses varies based on accumulator specifications, refrigerant type, and operational conditions, making it necessary to accurately grasp refrigerant amounts for effective liquid equalization control, which is challenging due to differing compressor thresholds.
Innovation Solution
An air-conditioning apparatus with a refrigerant amount calculation unit, a refrigerant differential amount calculation unit, and a liquid equalization control unit that calculates and controls the differential refrigerant amounts across multiple heat source apparatuses to equalize refrigerant accumulation, independent of compressor discharge superheat and refrigerant type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid equalization control is performed using compressor discharge superheat as a control target, then the control can be implemented, but the control accuracy deteriorates because different thresholds are required for different compressors based on their specifications and operating conditions
Solution Approach 1:
The patent introduces an accumulator as an intermediary component between the compressor and the rest of the refrigerant system. The accumulator accumulates refrigerant and provides a stable reference point for measurement. By measuring the temperature difference between the accumulator outlet and the compressor suction port, the system obtains an accurate indication of refrigerant amount without being affected by compressor-specific variations, thus resolving the contradiction between ease of control implementation and measurement accuracy.
2Adaptability or versatility
If different threshold values are set for each compressor based on specifications and operating conditions, then control can be adapted to different conditions, but the system complexity increases
Solution Approach 1:
The patent creates a universal control method that works for all compressors regardless of their specific specifications. The accumulator-based measurement system provides a standardized reference point that eliminates the need for compressor-specific threshold calibration. The same control algorithm and threshold values can be applied universally across different compressor types and operating conditions, thereby reducing system complexity while maintaining adaptability.
Data Source
AI summary
An air-conditioning apparatus including heat source apparatuses each including a compressor and an accumulator includes: a refrigerant amount calculation unit that calculates an amount of the refrigerant accumulated in the accumulator in one of the heat source apparatuses that is to be controlled; a refrigerant differential amount calculation unit configured to calculate, when the number of the heat source apparatuses is two, a differential amount between the calculated amount and an amount of the refrigerant in the accumulator in the other heat source apparatus, and calculate, when the number of the heat source apparatuses is three or more, a differential amount between the calculated amount of the refrigerant and an average amount of amounts of the refrigerant accumulated in the accumulators in the heat source apparatuses; and a liquid equalization control unit that controls the heat source apparatus to be controlled, based on the calculated differential amount.