Variable-Capacity Compressor Control for Shutdown-Aware Energy Savings
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Solution Overview
Problem
Climate-control systems, such as heat-pump and air conditioning systems, face inefficiencies in energy usage due to the inability to dynamically adjust compressor capacity based on demand and shutdown frequency, 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 the number of shutdowns within a predetermined time period, adjusting the low-capacity runtime threshold accordingly, and allowing user override for high-demand situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor operates in high-capacity mode to quickly meet heating or cooling demand, then the heating or cooling speed is improved, but energy consumption increases
Solution Approach 1:
The compressor capacity is made dynamic by switching between high-capacity and low-capacity modes based on real-time operating conditions. The control module monitors runtime thresholds and demand signals to dynamically adjust compressor capacity, allowing the system to quickly meet initial heating/cooling demands while conserving energy during maintenance phases.
Solution Approach 2:
The system changes the operational parameter of compressor capacity by switching between discrete capacity modes. The control module adjusts the capacity parameter based on runtime thresholds and demand signals, enabling the compressor to operate at high capacity when needed and low capacity for energy efficiency during prolonged operation.
2Use of energy by moving object
If the compressor frequently switches to shutdown state to conserve energy, then energy usage is reduced, but system reliability deteriorates
Solution Approach 1:
The control module implements preliminary action by monitoring runtime thresholds before shutdown occurs. When the low-capacity runtime threshold is exceeded, the system proactively transitions to high-capacity mode or prevents shutdown, ensuring the compressor remains operational and reliable while still managing energy consumption during normal operation.
Solution Approach 2:
The system uses feedback from runtime monitoring and demand signals to control shutdown decisions. The control module continuously tracks compressor runtime and compares it against thresholds, using this feedback to determine when to allow shutdown versus when to maintain operation, thereby balancing energy savings with system reliability.
3Use of energy by moving object
If the compressor operates in low-capacity mode to optimize energy efficiency, then energy efficiency is improved, but heating or cooling performance deteriorates
Solution Approach 1:
The compressor capacity is dynamically adjusted based on real-time system needs. The control module switches between low-capacity and high-capacity modes depending on whether the system is in a maintenance phase or experiencing high demand, ensuring optimal energy efficiency during steady-state operation while maintaining adequate performance during peak loading conditions.
Solution Approach 2:
The system employs periodic action by alternating between low-capacity operation for energy efficiency and high-capacity operation when demand requires. The control module uses runtime thresholds and demand signals to periodically switch capacity modes, allowing the system to achieve good energy efficiency over time while still meeting heating and cooling performance requirements when needed.
Data Source
AI summary
A climate-control system is provided that includes a variable-capacity compressor unit and a control module controlling the compressor unit. The compressor unit is 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 a number of times that the compressor unit has been switched into the shutdown state within a predetermined time period.