Protection method and device for high-temperature prevention during heating and refrigerant shortage during heating, and air conditioning system
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Solution Overview
Problem
Existing air conditioning systems face challenges in preventing high-temperature damage and refrigerant shortages during heating, particularly in fixed-frequency systems without indoor and outdoor unit communication, leading to inaccurate high-temperature prevention and potential misoperation.
Innovation Solution
A method and device that detect outdoor ambient temperature, exhaust temperature, and fan current in real-time to determine if high-temperature prevention is needed, using compensation temperatures to accurately assess the indoor unit's temperature state without communication, and differentiate between high-temperature prevention and refrigerant shortages, ensuring timely entry into high-temperature prevention mode and reporting faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outdoor fan is stopped intermittently to actively unload during heating in high-temperature environment, then the compressor is protected from excessive pressure, but the system complexity increases due to the need for indoor-outdoor unit communication to control the outdoor fan
Solution Approach 1:
The patent extracts the high-temperature prevention control function from the indoor-unit mainboard and relocates it to the outdoor-unit mainboard. This allows the outdoor fan to be controlled directly based on exhaust temperature detection without requiring communication with the indoor unit, thereby maintaining compressor protection while eliminating the need for complex communication systems in fixed-frequency air conditioners.
2Ease of operation
If the indoor heat exchanger temperature is used as the main control factor for high-temperature prevention, then the control is simple, but the accuracy of high-temperature prevention determination is insufficient leading to delayed response and potential compressor damage
Solution Approach 1:
The patent replaces the mechanical/physical measurement approach (directly measuring indoor heat exchanger temperature) with an indirect inference approach. The outdoor-unit mainboard infers the indoor heat exchanger temperature by detecting the exhaust temperature of the compressor and applying a compensation algorithm based on the temperature difference between outdoor ambient temperature and compressor exhaust temperature. This substitution maintains control simplicity while significantly improving the accuracy and timeliness of high-temperature prevention determination.
3Speed
If the exhaust temperature is used to determine high-temperature prevention, then the response is timely, but refrigerant shortage cannot be distinguished from high-temperature conditions leading to misoperation
Solution Approach 1:
The patent segments the exhaust temperature threshold into two distinct levels: a first threshold for high-temperature prevention and a second threshold for refrigerant shortage protection. When the exhaust temperature exceeds the first threshold, the system enters high-temperature prevention mode by controlling the outdoor fan. When the exhaust temperature exceeds the higher second threshold, the system determines refrigerant shortage and triggers fault protection by stopping the compressor. This segmentation allows the system to respond timely to temperature changes while accurately distinguishing between different fault conditions, preventing misoperation.
Data Source
AI summary
The present invention provides a protection method and device for high-temperature prevention during heating and refrigerant shortage during heating of an air conditioning system. The method comprises: in a heating mode, starting an outdoor fan, and detecting an outdoor ambient temperature, an exhaust temperature of a compressor, a fan current of the outdoor fan and an operating duration of the outdoor fan in real time; when the operating duration is greater than a first preset duration, comparing whether the sum of the exhaust and a compensation temperatures is greater than a first preset temperature and whether the fan current is greater than a preset current value; if yes, controlling the outdoor fan to stop operating and an indoor unit to operate normally.