System and method of controlling a variable-capacity compressor
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Solution Overview
Problem
Climate-control systems, such as heat-pump and refrigeration systems, face inefficiencies in energy usage due to the inability to dynamically adjust compressor capacity based on varying outdoor air temperatures and thermal loads, leading to suboptimal heating and cooling performance.
Innovation Solution
A climate-control system with a variable-capacity compressor and a control module that switches between low and high capacity modes based on demand signals, outdoor air temperature data, and air temperature slopes, using lookup tables to determine runtime settings and account for relative humidity and thermal loads, allowing for adaptive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor operates in high capacity mode continuously, then the heating or cooling speed is improved, but the energy efficiency deteriorates
Solution Approach 1:
The compressor capacity is made dynamic by switching between first and second capacity modes based on real-time monitoring of outdoor air temperature and temperature slope. The control module adjusts compressor operation from static fixed-capacity to dynamic variable-capacity, optimizing the balance between heating/cooling speed and energy efficiency according to environmental conditions.
Solution Approach 2:
The system changes the operational parameters of the compressor by switching between different capacity modes. The control module monitors outdoor air temperature and its rate of change, then adjusts the compressor capacity parameter accordingly - using high capacity mode when temperature changes rapidly and low capacity mode when conditions are stable, thereby optimizing energy efficiency while maintaining adequate heating or cooling performance.
2Use of energy by moving object
If the compressor operates in low capacity mode to save energy, then the energy efficiency is improved, but the heating or cooling speed deteriorates
Solution Approach 1:
The system dynamically adjusts compressor capacity based on environmental conditions. When outdoor air temperature is stable (low temperature slope), the compressor operates in low capacity mode to maximize energy efficiency. When temperature changes rapidly (high temperature slope), the system automatically switches to high capacity mode to ensure adequate heating or cooling speed, thus dynamically balancing energy efficiency and performance speed.
Solution Approach 2:
The control module changes the compressor capacity parameter in response to monitored temperature conditions. By switching between capacity modes based on outdoor air temperature and its rate of change, the system optimizes the parameter setting to achieve energy efficiency during stable conditions while maintaining the capability for high-speed operation when environmental conditions require rapid response.
3Device complexity
If the compressor capacity is fixed, then the device complexity is reduced, but the adaptability to varying environmental conditions deteriorates
Solution Approach 1:
The compressor control system transitions from static fixed-capacity operation to dynamic variable-capacity operation. The control module monitors outdoor air temperature and temperature slope, then dynamically switches between first and second capacity modes. This dynamic approach enhances adaptability to varying environmental conditions while maintaining relatively simple control logic based on temperature threshold comparisons.
Data Source
AI summary
A climate-control system may include a variable-capacity compressor unit and a control module controlling the compressor unit. The compressor unit may be operable in a first capacity mode and in a second capacity mode that is higher than the first capacity mode. The control module may be configured to switch the compressor unit among a shutdown state, the first capacity mode and the second capacity mode based on a demand signal and outdoor-air-temperature data.