Compressor Suction Valve PWM With Parallel Pressure Regulation
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Solution Overview
Problem
Existing refrigerant systems using pulse width modulation for suction valves face inefficiencies due to inability to maintain suction pressure at the lowest acceptable level across all operating conditions, leading to potential corona discharge, motor overheating, and reduced efficiency.
Innovation Solution
A pressure regulating valve is installed in parallel with the pulse width modulating valve to maintain a minimum acceptable pressure above 0.5 psia in the compressor shell by allowing limited refrigerant flow when low pressures are sensed, preventing detrimental effects while ensuring efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the suction valve is closed to reduce capacity using pulse width modulation, then the pressure inside the compressor shell drops to increase operational efficiency, but the pressure may drop below the minimum predetermined level causing corona discharge and motor overheating
Solution Approach 1:
A pressure regulating valve is introduced as an intermediary component in parallel with the pulse width modulating valve. This intermediary valve actively regulates the suction pressure by opening to allow refrigerant flow when pressure drops below the minimum level, preventing corona discharge and motor overheating while enabling the main valve to operate at fully closed positions for maximum efficiency.
2Reliability
If a leaky pulse width modulating valve or bypass loop with small opening is used to maintain minimum pressure, then the pressure remains above the minimum level, but the pressure becomes too high for some operating conditions leading to lower system efficiency
Solution Approach 1:
The pressure regulating valve replaces the static small opening with a dynamic, controllable valve that can adjust its opening degree based on real-time pressure conditions. This dynamic regulation allows the system to maintain minimum pressure when needed while avoiding excessive pressure buildup, optimizing efficiency across varying operating conditions.
Solution Approach 2:
The pressure regulating valve operates based on feedback from the suction pressure conditions. When pressure drops below the minimum level, the valve opens to allow refrigerant flow; when pressure is adequate, the valve remains closed. This feedback mechanism enables precise pressure control that adapts to changing system conditions.
3Loss of energy
If the suction pressure is maintained at the lowest possible level for all operating conditions, then system efficiency is maximized, but corona discharge and motor overheating occur when pressure drops below the minimum level
Solution Approach 1:
The pressure regulating valve provides preliminary protective action by monitoring and maintaining suction pressure above the minimum level before harmful effects like corona discharge and motor overheating can occur. This preventive mechanism allows the pulse width modulating valve to operate at fully closed positions for maximum efficiency without risking damage to the compressor.
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
The solution effectively maintains suction pressure above the minimum acceptable level, preventing corona discharge and motor overheating, while optimizing system efficiency across varying operating conditions.
Implementation Method 1
A pressure regulating valve is installed in parallel with the pulse width modulating valve to maintain a minimum acceptable pressure above 0.5 psia in the compressor shell by allowing limited refrigerant flow when low pressures are sensed
Implementation Method 2
The pulse width modulation control is provided for that suction valve. The pulse width modulation control is operable to rapidly cycle the valve between opened and closed positions (states) to change the capacity of the refrigerant system
Implementation Method 3
A compressor is associated with a refrigerant system... the compressor will consume less power for the same delivered capacity if the pressure inside the compressor shell within the suction region is reduced to the lowest possible value
Data Source
AI summary
A pulse width modulation control is provided for a suction valve on a suction line, delivering refrigerant into a housing shell of a compressor. When the suction valve is closed, the pressure within the housing shell can become very low. Thus, a pressure regulator valve is included within the refrigerant system to selectively deliver a limited amount of refrigerant into the housing shell when the suction valve is closed. The delivery of this limited amount of refrigerant ensures that a specified pressure is maintained within the housing shell to achieve the most efficient operation while at the same time preventing problems associated with damage to electrical terminals, motor overheating and excessive discharge temperature.