Air conditioner, control method, and non-transitory computer-readable recording medium
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Solution Overview
Problem
Conventional air conditioners face the risk of refrigerating machine oil depletion during intermittent operations due to prolonged low compressor frequencies, leading to reliability issues, especially in highly airtight or insulated rooms where heating or cooling capacity fluctuations cause frequent starts and stops, resulting in insufficient oil concentration and evaporation.
Innovation Solution
An air conditioner system with an operation frequency detector, time measurer, stop counter, and operation controller to detect low frequency operations, count stop times, and perform a recovery operation to restore oil concentration by increasing compressor frequency when certain conditions are met, such as stop counts exceeding a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor operates at low frequency for a long time, then energy consumption is reduced, but the refrigerating machine oil return performance deteriorates and oil concentration becomes insufficient
Solution Approach 1:
The control device performs preliminary action by detecting when the compressor operates at low frequency for a predetermined time or when stop frequency exceeds a threshold, and proactively increases the compressor frequency before oil concentration becomes critically low. This preventive approach ensures oil return performance is maintained while allowing extended low-frequency operation for energy savings.
2Reliability
If the compressor frequency is increased to improve oil return performance, then oil concentration is recovered, but energy consumption increases and comfort deteriorates due to frequent high-frequency operations
Solution Approach 1:
The system dynamically adjusts compressor frequency based on real-time operating conditions. Instead of maintaining constantly high frequency, the control device only increases frequency when oil return performance deteriorates (detected through operation time or stop frequency criteria), and returns to low frequency afterward. This dynamic adjustment recovers oil concentration while minimizing energy consumption and maintaining comfort.
3Reliability
If the compressor frequency is increased to improve oil return performance, then oil concentration is recovered, but user comfort deteriorates due to noticeable high-frequency operations
Solution Approach 1:
The control device dynamically increases compressor frequency only when necessary (when low-frequency operation time exceeds threshold or stop frequency is high), maintaining low frequency during normal operation for user comfort. The frequency adjustment is temporary and targeted, recovering oil return performance without causing noticeable discomfort from frequent or prolonged high-frequency operations.
Data Source
AI summary
An air conditioner has a refrigeration cycle in which a refrigerant circulates through a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger which are connected by pipes. The air conditioner includes: an operation frequency detector configured to detect an operation frequency of the compressor; an operation time measurer configured to, based on the operation frequency, measure a continuous time for which a low frequency operation in which the operation frequency of the compressor is equal to or lower than a reference frequency is continuously performed; a stop counter configured to, based on the continuous time, count a stop number of times the compressor is stopped without the continuous time continuing longer than a reference time; and an operation controller configured to, based on the stop number of times, perform a recovery operation that recovers a concentration of a refrigerating machine oil sealed inside the compressor.