Staging active cooling start-up
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Solution Overview
Problem
Multi-compressor air conditioning systems take a substantial amount of time to initiate operation under high load conditions, delaying the matching of interior region temperature to the set point due to sequential compressor staging without immediate knowledge of temperature drop upon activation.
Innovation Solution
The Optimum Stage-Up Algorithm, or Fast Compressor Start (FCS) process, estimates the number of compressor stages needed based on sensed temperatures and other variables, allowing simultaneous or staggered initiation of compressors to quickly meet cooling demands while avoiding electrical overload, thus reducing the time to reach the temperature set point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If compressors are staged individually and sequentially to control indoor supply air temperature, then the system maintains stable temperature control, but the time required to reach the temperature set point increases substantially under high load conditions
Solution Approach 1:
The controller performs preliminary calculation of the cooling load and predicts the number of compressors needed before actually starting them. This advance planning allows the system to bypass the traditional sequential one-at-a-time startup approach and instead prepare a staged sequence that can rapidly bring multiple compressors online in an optimized order, significantly reducing the time to reach the temperature set point while maintaining stable temperature control throughout the process
Solution Approach 2:
The system dynamically adjusts the compressor startup sequence based on real-time conditions including the calculated cooling load, ambient temperature, and system capabilities. Rather than following a fixed sequential pattern, the controller optimizes the startup sequence dynamically, allowing compressors to be staged in a manner that balances rapid cooling achievement with electrical load management and temperature stability requirements
2Loss of time
If all compressors are activated simultaneously to meet high cooling demand, then the time to reach temperature set point is minimized, but electrical overload may occur
Solution Approach 1:
The controller segments the compressor startup process into multiple stages based on the calculated cooling load. Instead of simultaneous activation or simple sequential startup, the system divides compressors into groups that will be activated in an optimized sequence. This segmentation allows the system to distribute the electrical load across time while still achieving rapid cooling response, preventing electrical overload while minimizing the time to reach the temperature set point
Solution Approach 2:
The system uses feedback from temperature sensors and load calculations to continuously monitor the cooling progress and adjust the compressor startup sequence in real-time. This feedback mechanism allows the controller to optimize the startup process dynamically, bringing compressors online in a sequence that responds to actual cooling needs while maintaining electrical system reliability and achieving the temperature set point as quickly as possible
Data Source
AI summary
A novel process for activating available compressors in multiple compressor air conditioning systems, using an Optimum Stage-Up Process. This process is programmed into a controller as an algorithm, to provide a process for fast compressor start. This process shortens the time to initiate operation of compressors in a multi-compressor air conditioning system required to meet the demand call under any load condition, and hence shortens the time required for the actual sensed interior region air temperature to reach the interior region temperature set point. The Optimum Stage-up Algorithm estimates the number of compressor stages or steps that must be initiated, based on sensed or measured values, to meet the demand at any load condition. These measured values include the sensed temperature of the interior region being cooled, which is compared to the temperature set point of this interior region as well as measured mixed air temperature and supply air temperature.