One method to mitigate vibration and sound level in heat pump chiller with evi function
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Solution Overview
Problem
Current refrigeration systems using air-supplying enthalpy-increasing compressors experience significant vibration and noise due to pressure fluctuations across check valves, which affect the service life of components and operational efficiency.
Innovation Solution
A heat pump system incorporating a pressure balance branch that connects the air supply branch to the low-pressure gas-phase side of the major heat exchange loop, allowing medium-pressure refrigerant to be exported and reused, thereby eliminating pressure differences and reducing valve vibration and noise. This configuration includes a major heat exchange loop with a compressor, flow-path switching valve, condenser, throttling elements, and an evaporator, along with an air supply branch and pressure balance branch to manage refrigerant flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is used to prevent refrigerant backflow in the air supply branch, then refrigerant flow control is improved, but valve vibration and noise increase due to pressure fluctuations
Solution Approach 1:
A pressure balance branch is introduced as an intermediary pathway between the air supply branch and the evaporator outlet. This mediator allows pressure equalization across the check valve by providing an alternative flow path for refrigerant, thereby reducing the pressure differential that causes valve vibration and noise while maintaining the check valve's flow control function.
Solution Approach 2:
The refrigerant flow path is segmented into multiple branches: the main air supply branch with the check valve, and the pressure balance branch connected to the evaporator outlet. This segmentation allows independent pressure management in each branch, reducing the harmful pressure fluctuations affecting the check valve while preserving its flow control reliability.
2Reliability
If the air supply branch is turned off during refrigeration mode to prevent backflow, then refrigerant flow direction is controlled, but medium-pressure refrigerant accumulates causing pressure imbalance
Solution Approach 1:
The pressure balance branch acts as a mediator that connects the closed air supply branch to the low-pressure zone at the evaporator outlet. When the air supply branch is closed during refrigeration mode, this intermediary pathway provides a pressure relief route, allowing medium-pressure refrigerant to equalize with low-pressure refrigerant and preventing pressure imbalance.
Solution Approach 2:
The pressure balance branch is pre-configured to activate automatically when the air supply branch closes. It provides preliminary pressure equalization before significant pressure buildup occurs, preventing the harmful effects of pressure imbalance without requiring active control intervention.
3Reliability
If medium-pressure refrigerant is blocked in the air supply branch, then backflow is prevented, but vibration and noise cause reduced service life of components
Solution Approach 1:
The pressure balance branch serves as a pressure equalization mediator that reduces the magnitude of pressure fluctuations across the check valve. By providing an alternative pathway for pressure relief, it maintains the backflow prevention function while minimizing the vibration and noise that would otherwise reduce component service life.
Solution Approach 2:
The medium-pressure refrigerant that would otherwise cause harmful vibrations is redirected through the pressure balance branch to the evaporator outlet. This converts the harmful pressure buildup into a beneficial pressure equalization process, maintaining backflow prevention while eliminating the damaging vibrations and extending component service life.
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 reduces valve vibration and noise, improves the degree of superheat for the compressor, and enhances the heating mode performance by ensuring that medium-pressure refrigerant is properly managed, leading to a more reliable and efficient operation.
Implementation Method 1
a pressure balance branch, which is connected from the air supply branch at the upstream of the switch valve to a low-pressure gas-phase refrigerant side of the major heat exchange loop
Implementation Method 2
the refrigerant, after being compressed by a compressor, flowing through a flow direction switching valve to an evaporator for condensation and heat dissipation
Implementation Method 3
the refrigerant being throttled by a first throttling element, being evaporated at a condenser for heat absorption
Implementation Method 4
the refrigerant, after being throttled by a second throttling element, flowing through the economizer and exchanging heat with the refrigerant flowing from the evaporator to the economizer
Data Source
AI summary
A heat pump system and a control method thereof. The heat pump system includes: a major heat exchange loop (100), including at least one compressor (110), a flow-path switching valve (120), a condenser (130), a first throttling element (140), an economizer (150), and an evaporator (160) that are connected sequentially to form a loop; and an air supply branch (200), which is connected from a flow path between the first throttling element and the economizer to an air supply inlet of the compressor, the air supply branch being provided with a switch valve (231) for preventing a gas-phase refrigerant from flowing back; where a pressure balance branch (300) is further included, which is connected from the air supply branch at the upstream of the switch valve to a low-pressure gas-phase refrigerant side of the major heat exchange loop.