Controlling compressor operation
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Solution Overview
Problem
Compressor surge occurs when the mass flow rate is low, leading to violent oscillations and hardware damage, which is a risk in vapour-compression cycles due to insufficient fluid compression, especially during low-demand operations.
Innovation Solution
Implementing a capacity modulation mode in the compressor operation, alternating between idle and high-speed modes to maintain the target temperature within a predetermined range, using processing circuitry to adjust compressor speed and avoid surge conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mass flow rate through the compressor is reduced to meet low heating or cooling demand, then the heating or cooling rate matches the demand, but the compressor operates in or close to surge conditions causing violent oscillations and hardware damage
Solution Approach 1:
The compressor operates in a capacity modulation mode where it periodically switches between a first speed (lower mass flow rate) and a second speed (higher mass flow rate). This periodic action allows the compressor to meet low heating or cooling demand while preventing sustained operation in surge conditions, thereby maintaining both productivity match and operational reliability
Solution Approach 2:
The compressor speed is made dynamic through capacity modulation, allowing it to adapt between two speeds based on operating conditions. This dynamic adjustment enables the system to respond to varying demand while avoiding the static low-speed surge region, resolving the contradiction between matching demand and maintaining stability
2Use of energy by moving object
If the compressor operates at low mass flow rate to match low demand, then energy consumption is reduced, but compressor surge occurs leading to violent oscillations
Solution Approach 1:
The compressor alternates between low-speed and high-speed operation in a periodic capacity modulation cycle. During low-demand periods, it briefly operates at first speed to match demand, then switches to second speed to prevent surge, thereby reducing overall energy consumption while eliminating harmful surge oscillations
Solution Approach 2:
The system converts the potential harm of surge oscillations into a beneficial control strategy by using periodic high-speed operation to prevent surge. The brief high-speed excursions, which would normally be wasteful, become a protective mechanism that eliminates harmful oscillations while maintaining acceptable energy consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Maintains the target temperature of the region being heated or cooled within a narrow range while preventing compressor surge, ensuring stable operation and preventing hardware damage.
Implementation Method 1
compress the refrigerant fluid, increasing the temperature and pressure thereof
Implementation Method 2
the temperature of the region to be heated or cooled is maintained to within a predetermined range of the target temperature
Data Source
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AI summary
Disclosed is processing circuitry for controlling the operation of a fluid compressor device configured to compress refrigerant vapour as part of a vapour-compression cycle to achieve a target temperature of a region to be heated or cooled. The processing circuitry is configured to obtain target temperature data indicating the target temperature to be achieved in the region to be heated or cooled, obtain temperature data indicating a temperature of the region to be heated or cooled; and obtain compressor data indicating a compressor parameter associated with the operation of the fluid compressor device. The processing circuitry is configured to determine, based on the compressor data, whether the fluid compressor device is approaching a surge state. If it is determined that the fluid compressor device is approaching the surge state, the processing circuitry is configured to cause the fluid compressor device to operate in a capacity modulation mode according to which the compressor speed is modulated between two speeds such that, in the capacity modulation mode, the temperature of the region to be heated or cooled is maintained to within a predetermined range of the target temperature.