Control mechanism for climate control unit with multiple stages
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Solution Overview
Problem
Climate-control systems with fixed-speed compressors often cycle frequently and struggle to match varying load demands due to their inability to adjust capacity in response to changing ambient and indoor conditions.
Innovation Solution
A climate-control system featuring a variable-capacity compressor that adjusts its stages based on outdoor and return air temperature slopes, indoor humidity, and space temperature differences, using sensors and a controller to dynamically modulate compressor capacity and fan speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed-speed compressor is used, then the system structure is simple, but the compressor cycles frequently and cannot match varying load demands
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed-speed compressor to a variable-capacity compressor that can dynamically adjust its operating speed and capacity. The compressor now operates across multiple stages (first stage, second stage, third stage) allowing it to adapt to varying load demands. This dynamic adjustment capability matches the compressor output to the actual cooling/heating requirements, reducing frequent cycling and improving operational stability while maintaining reasonable structural complexity through electronic control.
2Device complexity
If a fixed-speed compressor is used, then the device complexity is low, but the energy efficiency deteriorates due to frequent cycling
Solution Approach 1:
The patent implements feedback control by using temperature sensors (outdoor ambient temperature sensor, return air temperature sensor) to continuously monitor system conditions and feed this information back to the controller. The controller adjusts the compressor stage based on the temperature slope and system load demands, creating a closed-loop control system. This feedback mechanism enables the compressor to operate at optimal capacity levels, reducing energy waste from frequent on/off cycling and improving overall energy efficiency.
Solution Approach 2:
The variable-capacity compressor dynamically adjusts its operating speed and capacity based on real-time system conditions. By modulating the compressor output across multiple stages rather than operating at fixed high speed and cycling on/off, the system reduces energy consumption. The dynamic adjustment allows the compressor to match output to actual load requirements, eliminating the energy waste associated with frequent startup and shutdown cycles.
3Device complexity
If a fixed-speed compressor is used, then the manufacturing cost is low, but the adaptability to changing conditions deteriorates
Solution Approach 1:
The patent applies dynamics by enabling the compressor to operate across multiple capacity stages (first stage, second stage, third stage) rather than at a single fixed speed. The controller selectively commands different compressor stages based on outdoor ambient temperature, return air temperature slope, and space temperature differences. This dynamic adaptability allows the system to efficiently handle varying load demands, from part-load to full-load conditions, improving versatility while maintaining reasonable system complexity through electronic control.
Solution Approach 2:
The patent implements parameter changes by varying the compressor operating parameters (speed, capacity stage) based on changing environmental and operational conditions. The controller monitors temperature parameters and adjusts the compressor stage accordingly, changing the system's operating point to match load demands. This parameter adjustment capability enhances adaptability to different outdoor temperatures and indoor load conditions while maintaining a relatively simple compressor hardware design.
Data Source
AI summary
A climate-control system includes a variable-capacity compressor. An outdoor ambient temperature sensor indicates a temperature of the outdoor ambient air. A return air temperature sensor indicates a temperature of the return air in the system. A controller commands a startup compressor stage based on the temperature from the outdoor ambient temperature sensor and commands a running compressor stage based on a time-based slope of the temperature from the return air temperature sensor and the startup compressor stage.