Compressor Operating Limit Adjustment for Rapid Refrigerant Cooldown
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Solution Overview
Problem
Refrigerant systems often shut down when operating near or above safe limits, leading to inefficiencies and potential damage, especially during rapid cooldowns or high ambient temperature conditions, resulting in issues like food spoilage or discomfort in climate-controlled spaces.
Innovation Solution
A method and control system that allows temporary alteration or elimination of safe operating limits for compressors, enabling operation beyond predefined limits for short periods, either manually or automatically, based on sensed conditions, to facilitate rapid temperature changes without immediate shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor operates above safe discharge temperature or pressure limits, then rapid cooldown of refrigerated container or conditioned space can be achieved, but compressor damage may occur
Solution Approach 1:
The patent applies dynamics by making the safe operating limits adjustable rather than fixed. The control system dynamically modifies the discharge temperature and pressure limits based on operating conditions such as ambient temperature, condensing temperature, and whether a pulldown mode is active. This allows the system to temporarily operate above traditional safe limits during rapid cooldown while maintaining safety under normal conditions.
Solution Approach 2:
The patent changes the parameters of safe operating limits based on environmental and operational conditions. Specifically, the discharge temperature limit and discharge pressure limit are modified as functions of ambient temperature, condensing temperature, and pulldown mode status. This enables the system to adapt the safety thresholds to match the actual risk profile of different operating scenarios.
2Productivity
If the compressor operates near safe limits during high ambient temperature conditions, then cooling efficiency improves, but system shutdown may occur leading to food spoilage or discomfort
Solution Approach 1:
The control system dynamically adjusts the discharge temperature and pressure limits based on ambient temperature conditions. During high ambient temperature operations, the system raises the safe operating limits to prevent unnecessary shutdowns, allowing the compressor to continue operating efficiently even under stressed conditions. This dynamic adjustment prevents system downtime and associated losses.
3Reliability
If traditional fixed safe operating limits are enforced, then compressor protection is ensured, but system flexibility and adaptability to different operating conditions deteriorates
Solution Approach 1:
The patent transforms fixed safe operating limits into dynamic, condition-dependent limits. The control system continuously monitors ambient temperature, condensing temperature, and operational mode to determine appropriate limit values. This dynamic approach maintains compressor protection while adapting to various operating scenarios including high ambient temperature, rapid cooldown, and normal steady-state operation.
Solution Approach 2:
The safe discharge temperature and pressure parameters are changed based on operating conditions. The system calculates modified limits as functions of ambient temperature, condensing temperature, and pulldown mode. This parameter adaptation allows the system to maintain reliability while achieving flexibility across different operational environments.
Data Source
AI summary
A refrigerant system includes a compressor that has safe operating limits that are also built into a refrigerant system control to protect the compressor. Under certain conditions, these safe operational limits may be changed to allow the compressor to operate beyond the safety limits at least for a period of time.