Compressor Bypass Pressure Control in Low-Load Air Conditioners
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air conditioners face inefficiencies and reliability issues during low-load operations due to abnormal pressure fluctuations, leading to compressor overload and oil formation, which are not effectively managed by existing frequency control methods.
Innovation Solution
The air conditioner employs a dual-compressor system with parallel oil separators, a supercooling heat-exchanger, and adjustable bypass and injection valves to control refrigerant flow, allowing for fuzzy control of compressor frequency and pressure adjustment through a bypass passage to maintain optimal operation pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor operates at the lowest frequency to control high pressure, then energy consumption is reduced, but the compressor reliability deteriorates due to oil formation and operating out of range
Solution Approach 1:
A bypass passage is introduced as an intermediary path that allows refrigerant to flow directly from the condenser to the gas/liquid separator, bypassing the compressor. This mediator enables pressure control without requiring the compressor to operate at extremely low frequencies, thus maintaining compressor reliability while achieving energy savings.
Solution Approach 2:
The refrigerant flow path is segmented into multiple independent paths: the main path through the compressor and the bypass path directly from condenser to gas/liquid separator. This segmentation allows independent control of refrigerant flow through each path, enabling the system to maintain compressor operation within reliable frequency ranges while controlling system pressure.
2Stress or pressure
If the compressor operates at lowest frequency to maintain target pressure, then high pressure control is improved, but the compressor operates out of operable range causing deterioration
Solution Approach 1:
The bypass passage acts as an intermediary pressure control mechanism that relieves the compressor from the burden of maintaining target pressure alone. By providing an alternative refrigerant flow path, the bypass system directly controls high pressure without requiring the compressor to operate at the edge of its operable range.
Solution Approach 2:
The control unit continuously monitors high pressure and dynamically adjusts the bypass valve opening degree based on feedback from pressure sensors. This closed-loop feedback control enables precise pressure regulation while keeping the compressor operating frequency within the reliable operable range, preventing oil formation and other reliability issues.
3Reliability
If a bypass passage is added to control pressure, then compressor reliability is improved, but device complexity increases
Solution Approach 1:
The bypass passage is designed to serve multiple functions: pressure control, refrigerant flow regulation, and compressor protection. By making this single structural component multi-functional, the patent reduces the need for additional separate devices, thereby limiting the increase in overall system complexity while achieving reliability improvements.
4Stress or pressure
If the bypass valve opening degree is increased to reduce high pressure, then pressure control is improved, but refrigerant circulation efficiency decreases
Solution Approach 1:
The bypass valve opening degree is dynamically adjusted based on real-time pressure conditions and operational requirements. The control unit optimizes the valve position to achieve the minimum necessary bypass flow for pressure control, thereby maintaining refrigerant circulation efficiency while effectively managing high pressure. This dynamic adjustment prevents excessive bypass flow that would reduce system productivity.
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
This solution improves compressor operation efficiency and reliability by reducing energy loss and maintaining optimal pressures during low-load conditions, preventing compressor overload and oil formation.
Implementation Method 1
a supercooling heat-exchanger
Implementation Method 2
a gas/liquid separator to separate a gaseous refrigerant to introduce the separated gaseous refrigerant into the compressor
Implementation Method 3
a compressor to compress a refrigerant
Implementation Method 4
an outdoor heat-exchanger provided in an outdoor unit or device may serve as a condenser, and an indoor heat-exchanger provided in an indoor unit or device may serve as an evaporator
Data Source
AI summary
An air conditioner and a method of controlling an air conditioner are provided. The method of controlling an air conditioner may include determining whether a low-load condition is satisfied on the basis of a number of indoor devices or a temperature of external air, performing a low-load operation of a compressor at a predetermined frequency when the low-load condition is satisfied, detecting whether an operation pressure is out of a target pressure value or range while the low-load operation is performed, and bypassing a refrigerant from the compressor to a gas/liquid separator via an injection passage when the operation pressure is out of the target pressure value or range.