Compressor Pressure Ratio Control for Low-Temperature Heating
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Solution Overview
Problem
Air conditioning systems face damage due to prolonged operation at high pressure ratios, which can occur in low-temperature heating environments, leading to unsafe compressor operation.
Innovation Solution
A pressure ratio control method that adjusts the compressor's output level-by-level by acquiring actual pressure ratios and shifting levels based on preset ratios to maintain the compressor within a safe operating range, preventing long-term operation at high pressure ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor operates at high output in low-temperature heating environment, then the cooling/heating effect is improved, but the pressure ratio becomes excessively high causing compressor damage
Solution Approach 1:
The control device continuously monitors the pressure ratio between compressor discharge and suction sides, and automatically adjusts compressor output based on feedback signals. When pressure ratio exceeds preset thresholds, the system reduces compressor capacity level-by-level until the pressure ratio returns to the safe operating range, thereby preventing compressor damage while maintaining productivity.
Solution Approach 2:
The compressor operates with dynamically adjustable output levels rather than fixed capacity. The system provides multiple compression levels (first, second, third levels) that can be switched in real-time based on operating conditions. This dynamic adjustment allows the compressor to adapt its output to match system requirements while maintaining safe pressure ratios.
2Reliability
If the compressor output is reduced to maintain safe pressure ratio, then compressor reliability is improved, but the cooling/heating capacity decreases
Solution Approach 1:
The system applies partial action by reducing compressor output only to the extent necessary to maintain safe pressure ratios, rather than shutting down completely. The multi-level compression capability allows the compressor to operate at reduced but still productive levels (second or third levels), maintaining adequate cooling/heating capacity while ensuring reliability.
Solution Approach 2:
The dynamic multi-level compression system allows flexible adjustment between different output levels. When pressure ratio is normal, the compressor operates at high output (first level) for maximum productivity. When pressure ratio approaches dangerous levels, the system dynamically transitions to lower levels (second or third), balancing reliability requirements with continued productive operation.
Data Source
AI summary
Disclosed are an air conditioning system and its pressure ratio control method and device. The method includes: acquiring an actual pressure ratio of the compressor every preset time period in operation of the air conditioning system; judging whether the actual pressure ratio is greater than or equal to the first pressure ratio corresponding to a current level; controlling the compressor to downshift one level for operation if the actual pressure ratio is greater than or equal to the first pressure ratio corresponding to the current level; further judging whether the actual pressure ratio is less than the second pressure ratio corresponding to the current level if the actual pressure ratio is less than the first pressure ratio corresponding to the current level; and controlling the compressor to upshift one level for operation if the actual pressure ratio is less than the second pressure ratio corresponding to the current level.